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NSDL National Science Digital Library
This site, created by Pamela J. W. Gore at Georgia Perimeter College, provides a concise explanation of the geologic principles of radiometric dating. Students can learn about the fundamentals of half lives, isotopes, and dating minerals. There are also descriptions of how Carbon-14 and Fission Track dating work.
Gore, Pamela J.
NSDL National Science Digital Library
The first website (1), created by Pamela J. W. Gore at Georgia Perimeter College, provides a concise explanation of the geologic principles of radiometric dating. Students can learn about the fundamentals of half lives, isotopes, and dating minerals. Secondly, the Museum Victoria offers a useful overview of radioactive decay of Potassium-40 and Carbon-14 (2). The website discusses the benefits of isotopes for the research interests of geologists and physicists. Next, Dr. Ben Waggoner at the University of Central Arkansas provides an online educational slide show discussing the assumptions, objections, and accuracy of radiometric dating (3). With an abundance of figures and images, visitors can learn about dateable materials, decay principles, and more. The fourth website, developed by Professor Stephen A. Nelson at Tulane University, provides a detailed mathematical explanation of the principles of radiometric dating (4). Users can view the data utilized for the corrections and can access the on-line form of CALIB, which converts radiocarbon ages to calendar years. The sixth website describes the Scottish Universities Research and Reactor Centre's work utilizing luminescence and radiocarbon dating (6). Through this expansive website, visitors can learn about the centre's many research projects including radioactive contamination, isotope geology, and environmental gamma spectrometry. Next, the North Carolina State University provides a fun, educational activity about radioactive isotope decay (7). Students can learn about the half lives of elements with the use of only candy, bags, and graph paper. Lastly, the University of North Carolina - Chapel Hill chemistry department discusses five different types of radioactive decay (8). After examining the numerous equations, students can test their dating skills by solving the practice problems.
Tulane University: Radiometric Dating
NSDL National Science Digital Library
The fourth website, developed by Professor Stephen A. Nelson at Tulane University, provides a detailed mathematical explanation of the principles of radiometric dating. The site is divided into sections which include: Principles of Radiometric Dating; The Rb/Sr System; The U, Th, Pb System; and The Age of the Earth. Other dating methods are covered briefly as well, such as potassium argon (K-Ar) dating and carbon-14. Professor Nelson concludes with a description of other users of isotopes.
Nelson, Stephen A.
ERIC Educational Resources Information Center
Discusses the accuracy of dating methods and creationist arguments that radiometric dating does not work. Explains the Manson meteorite impact and the Pierre shale, the ages of meteorites, the K-T tektites, and dating the Mount Vesuvius eruption. (Author/YDS)
Dalrymple, G. Brent
Estimation of Sediment Rates and Life of Sagar Lake Using Radiometric Dating Techniques
Sagar Lake is situated in the middle of the Sagar City in the Vindhyan terrain of Bundelkhand region of India at an elevation\\u000a of 517�m above mean sea level. The lake surface area and volume are 145?�?104�m2 and 389?�?104�m3 at full tank level. Sedimentation rates and pattern in the lake have been estimated using 137Cs and 210Pb radiometric dating techniques.
Surjeet Singh; L. N. Thakural; Bhishma Kumar
The method of dating rocks and minerals is known as geochronology. Although in principle this term could be applied to estimation of relative ages according to traditional geological observation, it is nowadays usually restricted to the quantitative measurement of geological time using the constant-rate natural process of radioactive decay. 14C dating is a technique based on measuring the residual radioactivity
R J Pankhurst
NASA Astrophysics Data System (ADS)
The method of dating rocks and minerals is known as geochronology. Although in principle this term could be applied to estimation of relative ages according to traditional geological observation, it is nowadays usually restricted to the quantitative measurement of geological time using the constant-rate natural process of radioactive decay. 14C dating is a technique based on measuring the residual radioactivity of this isotope which decays exponentially from the time of death of organisms which extract it from the atmosphere (e.g. when a living tree becomes simply 'wood'). The halflife of this decay is only 5600 years. Even using pre-concentration techniques and highly sensitive detectors, the practical range of the dating method does not extend back beyond about 100000 years-a period utterly insignificant in terms of the geological evolution of the Earth, which extends over the past 4500 million years. For geological dating one requires naturally occurring elements with much longer halflives. Most of the handful of appropriate decay schemes are listed. Most of the parent elements are rare metal constituents in the bulk chemical composition of the Earth. For such 'trace' elements it is generally convenient to express their concentration in natural materials in parts per million by weight (ppm) and even in the one case of a fairly common element (potassium) only a very small proportion occurs as the radioactive 40K. Also, some of the halflives are very long, even by geological reckoning, so that the actual level of natural radioactivity is rarely more than a few disintegrations per minute per gram.
Pankhurst, R. J.
Radiometric Dating in Geology.
ERIC Educational Resources Information Center
Described are several aspects and methods of quantitatively measuring geologic time using a constant-rate natural process of radioactive decay. Topics include half lives and decay constants, radiogenic growth, potassium-argon dating, rubidium-strontium dating, and the role of geochronology in support of geological exploration. (DS)
Pankhurst, R. J.
Use of radiometric (Cs137, Pb210), geomorphic, and stratigraphic techniques to date recent oxbow sediments in the rio puerco drainage Grants uranium region, New Mexico
In the absence of historic geochemical baseline data for the Grants uranium region, environmental changes resulting from uranium\\u000a mine-mill activities can be determined only by indirect methods. A methodology for determining the age of recent sediments\\u000a in streams draining the region has been established based on combined geomorphic, stratigraphic, and radiometric dating techniques.\\u000a Because clayrich sediments retain possible radionuclides and
Carl J. Popp; John W. Hawley; David W. Love; Michael Dehn
Topic in Depth - Radiometric Dating
NSDL National Science Digital Library
There have been many modern scientific pushes to discover the age of natural and human-made artifacts and this folder describes some of them. Carbon-14 and Potassium Argon dating are just a few covered here in lesson plans, lectures, and overviews.
Use of radiometric (Cs-137, Pb-210), geomorphic, and stratigraphic techniques to date recent oxbow sediments in the Rio Puerco drainage Grants uranium region, New Mexico
In the absence of historic geochemical baseline data for the Grants uranium region, environmental changes resulting from uranium mine-mill activities can be determined only by indirect methods. A methodology for determining the age of recent sediments in streams draining the region has been established based on combined geomorphic, stratigraphic, and radiometric dating techniques. Because clay-rich sediments retain possible radionuclides and heavy metals derived from mineralization and mined sources, sample sites which contain fine-grained deposits that both predate and postdate mine-mill activity were located in abandoned-channel segments (oxbows) of major streams draining the eastern Grants uranium region. Aerial photographs (and derivative maps) taken between 1935 and 1971 provided the historical and geomorphic documentation of approximate dates of oxbow formation and ages of alluvial fills in the abandoned-channel segments. Pits were dug at these oxbow sites to determine stratigraphy and composition of the deposits. Samples collected from pit walls and auger holes below the pits were subjected to radiometric analysis by gamma ray spectrometry for the artificial radionuclide Cs-137 and the natural radionuclide Pb-210 as well as other U-238 and Th-232 daughters. Because of the dynamic nature of the system, absolute dating with Cs-137 was not possible but samples could be dated as either pre- or post-1950. The 1950 date is important because it marked the beginning of the uranium exploitation in the region. The Pb-210 dating was not possible because background Pb-210 was very high relative to fallout Pb-210.
Popp, C.J.; Dehn, M. (New Mexico Inst. of Mining and Tech., Socorro (United States)); Hawley, J.W.; Love, D.W. (New Mexico Bureau of Mines and Mineral Resources, Socorro (United States))
Lunar highland stratigraphy and radiometric dating
The relevance of lunar highland rock ages to highland and basin stratigraphy is discussed. It is found that radiometric age data for highland rocks do not in any simple way reflect the time of excavation of the major circular basins from which they are believed to originate. Instead, many rocks are of a more local origin and, moreover, radiometric clocks
P. Horn; T. Kirsten
Radiometric dating of sediment records in European mountain lakes
Sediment cores from seven European mountain lakes collected as part of a study of palaeolimnogical records of climate change (the MOLAR project) were dated radiometrically by 210Pb. In spite of the remote locations, only one site recorded more or less uni- form sediment accumulation throughout the past 150 years. At three further sites the 210Pb record indicated uniform sedimentation up
Peter G. APPLEBY
Radiometric dating of the Siloam Tunnel, Jerusalem
The historical credibility of texts from the Bible is often debated when compared with Iron Age archaeological finds (refs . 1, 2 and references therein). Modern scientific methods may, in principle, be used to independently date structures that seem to be mentioned in the biblical text, to evaluate its historical authenticity. In reality, however, this approach is extremely difficult because
Amos Frumkin; Aryeh Shimron; Jeff Rosenbaum
Radiometric and tephroanalysis dating of recent Ionian Sea cores
Summary��An accurate dating of recent Ionian Sea sediment cores has been performed by the210Pb radiometric method and by a detailed tephroanalysis. The markers of the historical volcanic eruptions which occurred in\\u000a the Campanian area (Vesuvius, Phlegrean Fields, Ischia) during the last two millenia have been identified along the cores.\\u000a Among the others, the famous Plinian Vesuvius eruption of 79 AD,
G. Bonino; G. Cini Castagnoli; E. Callegari; Guang-Mei Zhu
Radiometric 81Kr dating identifies 120,000-year-old ice at Taylor Glacier, Antarctica.
We present successful (81)Kr-Kr radiometric dating of ancient polar ice. Krypton was extracted from the air bubbles in four ?350-kg polar ice samples from Taylor Glacier in the McMurdo Dry Valleys, Antarctica, and dated using Atom Trap Trace Analysis (ATTA). The (81)Kr radiometric ages agree with independent age estimates obtained from stratigraphic dating techniques with a mean absolute age offset of 6 � 2.5 ka. Our experimental methods and sampling strategy are validated by (i) (85)Kr and (39)Ar analyses that show the samples to be free of modern air contamination and (ii) air content measurements that show the ice did not experience gas loss. We estimate the error in the (81)Kr ages due to past geomagnetic variability to be below 3 ka. We show that ice from the previous interglacial period (Marine Isotope Stage 5e, 130-115 ka before present) can be found in abundance near the surface of Taylor Glacier. Our study paves the way for reliable radiometric dating of ancient ice in blue ice areas and margin sites where large samples are available, greatly enhancing their scientific value as archives of old ice and meteorites. At present, ATTA (81)Kr analysis requires a 40-80-kg ice sample; as sample requirements continue to decrease, (81)Kr dating of ice cores is a future possibility. PMID:24753606
Buizert, Christo; Baggenstos, Daniel; Jiang, Wei; Purtschert, Roland; Petrenko, Vasilii V; Lu, Zheng-Tian; M�ller, Peter; Kuhl, Tanner; Lee, James; Severinghaus, Jeffrey P; Brook, Edward J
Radiometric 81Kr dating identifies 120,000 year old ice at Taylor Glacier, Antarctica (Invited)
NASA Astrophysics Data System (ADS)
Ice cores from the Greenland and Antarctic ice sheets provide highly resolved, well-dated climate records of past polar temperatures, atmospheric composition and aerosol loading up to 800 ka before present. In addition to deep ice cores, old ice can also be found at ice margin sites and blue ice areas (BIAs) where it is exposed due to local ice dynamics and ablation. BIAs have great potential for paleoclimate studies, as large quantities of old ice are available at the surface where it can be sampled with relative ease. Determining the age of the ablating ice is the main difficulty in using BIAs for climate reconstructions. There is significant scientific interest in obtaining glacial ice dating beyond 800ka, as such an archive would extend the ice core record further back in time; such old ice can potentially be found in Antarctic BIAs such as the Allan Hills site, providing a strong impetus to developing reliable (absolute) dating tools for glacial ice. 81Kr is naturally produced in the upper atmosphere by cosmic ray interactions with the stable isotopes of Kr. The long half-life (229 ka) of 81Kr allows for radiometric dating in the 50 ka - 1.5 Ma age range, well past the reach of radiocarbon dating. Recent technological advances in Atom Trace Trap Analysis (ATTA) have reduced sample requirements to 40-80 kg of ice, which can realistically be obtained from BIAs and ice margins. We present the first successful 81Kr-Kr radiometric dating of ancient polar ice. Krypton was extracted from the air bubbles in four ~350 kg polar ice samples from Taylor Glacier in the McMurdo Dry Valleys, Antarctica, and dated using ATTA. The 81Kr radiometric ages agree with independent age estimates obtained from stratigraphic dating techniques with a root mean square offset of 6.5 ka. Our experimental methods and sampling strategy are validated by 1) 85Kr and 39Ar analyses that show the samples to be free of modern air contamination, and 2) air content measurements that show the ice did not experience gas loss. We estimate the error in the 81Kr ages due to past geomagnetic variability to be below 3 ka. We show that ice from the Eemian interglacial period (130-115ka BP) can be found in abundance near the surface of Taylor Glacier. Our study paves the way for reliable radiometric dating of ancient ice in blue ice areas and margin sites, greatly enhancing their scientific value as archives of old ice and meteorites. As sample requirements continue to decrease, 81Kr dating of ice cores is a future possibility.
Buizert, C.; Baggenstos, D.; Jiang, W.; Purtschert, R.; Petrenko, V. V.; Lu, Z.; M�ller, P.; Kuhl, T.; Lee, J.; Severinghaus, J. P.; Brook, E.
Paleomagnetic stratigraphy and radiometric dating of the pliocene volcanic rocks of Aegina, Greece
The island of Aegma includes some of the oldest volcanic rocks in the south Hellenic Arc previous radiometric dates range\\u000a from 3.87 to 4.4 Ma. The volcanic sequence is divided into nine units on the basis of field relations, petrography and geochemistry,\\u000a and the characteristic paleomagnetic polarity of each unit has been determined. Two new radiometric dates (2.1 and 3.9
G. Pe-Piper; D. J. W. Piper; P. H. Reynolds
Radiometric dating of brittle fault rocks; illite polytype age analysis and application to the Spanish Pyrenees
A variety of approaches have been available to indirectly date the timing of deformation and motion on faults, but few approaches for direct, radiometric dating of shallow crustal fault rocks were available until recently. The growing recognition of clay neomineralization at low temperatures in many fault rocks, particularly the 1Md illite polytype, allows the successful application of Ar dating to
B. A. van der Pluijm; S. H. Haines
How Old Is It? How Do We Know? A Review of Dating Methods� Part One: Relative Dating, Absolute Dating, and Non-radiometric Dating Methods
Davis A. Young The essential ideas behind the major methods for assessing the relative ages of geological and archeological materials and events are reviewed. These include the principles of original horizontality, superposition, inclusion, cross-cutting relations, and cross-dating by index fossils (biological succession) or artifacts. Some general principles of absolute dating are intro- duced, and, as representatives of non-radiometric methods, tree-ring,
Davis A. Young
The Blake geomagnetic excursion recorded in a radiometrically dated speleothem
NASA Astrophysics Data System (ADS)
One of the most important developments in geomagnetism has been the recognition of polarity excursions of the Earth's magnetic field. Accurate timing of the excursions is a key point for understanding the geodynamo process and for magnetostratigraphic correlation. One of the best-known excursions is the Blake geomagnetic episode, which occurred during marine isotope stage MIS 5, but its morphology and age remain controversial. Here we show, for the first time, the Blake excursion recorded in a stalagmite which was dated using the uranium-series disequilibrium techniques. The characteristic remanent magnetisation is carried by fine-grained magnetite. The event is documented by two reversed intervals (B1 and B2). The age of the event is estimated to be between 116.5�0.7 kyr BP and 112.0�1.9 kyr BP, slightly younger (�3-4 kyr) than recent estimations from sedimentary records dated by astronomical tuning. Low values of relative palaeointensity during the Blake episode are estimated, but a relative maximum in the palaeofield intensity coeval with the complete reversal during the B2 interval was observed. Duration of the Blake geomagnetic excursion is 4.5 kyr, two times lower than single excursions and slightly higher than the estimated diffusion time for the inner core (�3 kyr).
Osete, Mar�a-Luisa; Mart�n-Chivelet, Javier; Rossi, Carlos; Edwards, R. Lawrence; Egli, Ramon; Mu�oz-Garc�a, M. Bel�n; Wang, Xianfeng; Pav�n-Carrasco, F. Javier; Heller, Friedrich
Radiometric Dating by Alpha Spectrometry on Uranium Series Nuclides.
National Technical Information Service (NTIS)
This thesis describes the analytical and technical procedures that are required for routine application of both the (sup 230 Th) (sup 234) U disequilibrium dating method for peat and the (sup 210) Pb dating method for lake sediments. Its principal aim is ...
A. Wijk
Radiometric Dating of the United Kingdom SWAP Sites
Measurements of 210Pb by direct gamma assay have been used to date sediment cores from Surface Water Acidification Project (SWAP) study sites in the U.K. The results were checked against additional dating evidence from the artificial fallout isotopes 137Cs and 241Am. At one of the sites, Devoke Water in Cumbria, the 137Cs and 241Am data were crucial in identifying a
P. G. Appleby; N. Richardson; P. J. Nolan; F. Oldfield
Radiometric dating of lake sediments from Signy Island (maritime Antarctic): evidence of recent climatic change
Sediment cores from three lakes (Moss, Sombre and Heywood) in the maritime Antarctic (Signy Island, South Orkney Islands) have been successfully dated radiometrically by210Pb and137Cs. The core inventories of both fallout radionuclides are an order of magnitude higher than that which can be supported by the direct atmospheric flux at this latitude. The elevated values may be explained by fallout
P. G. Appleby; V. J. Jones; J. C. Ellis-Evans
14C-AMS at the Leibniz-Labor: radiometric dating and isotope research
The Leibniz-Labor was founded to provide radiometric dating services using AMS and measured over 15000 samples and 26800 targets up to September 2002. Research and development have primarily been directed at improving the efficiency and reliability of AMS measurements, optimising existing sample preparation procedures for AMS and developing new ones. The standard chemical pre-treatment of organic radiocarbon samples produces often
Pieter M Grootes; Marie-Jos�e Nadeau; Anke Rieck
Radiometric dating of time of thrusting in the disturbed belt of Montana
Mesozoic sedimentary rocks overridden by thrust plates in the disturbed belt of northwestern Montana have been metamorphosed by burial beneath these plates. Bentonite in the Cretaceous section has been converted to potash bentonite by this metamorphism, allowing radiometric dating of the emplacement of the thrust plates by the K-Ar method. Ages determined thus far range from 72 to 56 m.y.
Janet Hoffman; John Hower; James L. Aronson
Radiometric dating of sedimentary rocks: the application of diagenetic xenotime geochronology
Recent advances in the field of geochronology have led to a greater understanding of the scale and duration of geological processes. It is currently possible to date igneous and metamorphic rocks by a variety of radiometric methods to within a million years, but establishing the depositional age of sedimentary rocks has remained exceedingly difficult. The problem is most pronounced for
Birger Rasmussen
In situ radiometric dating on Mars: Investigation of the feasibility of KAr dating using flight-type mass and X-ray spectrometers
The absolute chronology of Mars is poorly known and, as a consequence, a key science aim is to perform accurate radiometric dating of martian geological materials. The scientific benefits of in situ radiometric dating are significant and arguably of most importance is the calibration of the martian cratering rate, similar to what has been achieved for the Moon, to reduce
D. L. Talboys; S. Barber; J. C. Bridges; S. P. Kelley; D. Pullan; A. B. Verchovsky; G. Butcher; A. Fazel; G. W. Fraser; C. T. Pillinger; M. R. Sims; I. P. Wright
Radiometric dating of sediment records from mountain lakes in the Tatra Mountains
Sediment cores from nine different lakes in the Tatra Mountains, collected as part of the EU funded AL:PE, MOLAR and EMERGE\\u000a projects investigating natural environmental records stored in remote mountain lake sediment sequences, were dated radiometrically\\u000a by 210Pb and 137Cs. At five sites, D?ugi Staw G?sienicowy and Zielony Staw G?sienicowy on the Polish side of the Tatra Mountains and Starolesnianske
Peter G. Appleby; Gayane T. Piliposian
Calibrating Late Quaternary terrestrial climate signals: radiometrically dated pollen evidence from the southern Sierra Nevada, USA
We constructed a radiometrically calibrated proxy record of Late Pleistocene and Holocene climate change exceeding 230,000yr duration, using pollen profiles from two cores taken through age-equivalent dry lakes�one core having greater age control (via 230Th alpha mass-spectrometry) and the other having greater stratigraphic completeness. The better dated of these two serial pollen records (Searles Lake) served as a reference section
Ronald J. Litwin; Joseph P. Smoot; Nancy J. Durika; George I. Smith
New radiometric dating of water management features at the prehistoric Purr�n Dam Complex, Tehuac�n Valley, Puebla, M�xico
Recent investigations at the prehistoric Purr�n Dam Complex in the Tehuac�n Valley of southern Puebla, M�xico applied radiometric dating to more securely date the complex. Ceramic-based dating in the 1960?s placed the Dam's origin to the Formative Period. While Formative Period origins are widely accepted, the chronology lacks resolution and direct dates. Samples from impounded sediments behind the dam and
Michael J. Aiuvalasit; James A. Neely; Mark D. Bateman
Calibrating Late Quaternary terrestrial climate signals: radiometrically dated pollen evidence from the southern Sierra Nevada, USA
We constructed a radiometrically calibrated proxy record of Late Pleistocene and Holocene climate change exceeding 230,000 yr duration, using pollen profiles from two cores taken through age-equivalent dry lakes - one core having greater age control (via 230Th alpha mass-spectrometry) and the other having greater stratigraphic completeness. The better dated of these two serial pollen records (Searles Lake) served as a reference section for improving the effective radiometric age control in a nearby and more complete pollen record (Owens Lake) because they: (1) are situated ~90 km apart in the same drainage system (on, and immediately leeward of, the eastern flank of the Sierra Nevada), and (2) preserved strikingly similar pollen profiles and concordant sequences of sedimentological changes. Pollen assemblages from both lakes are well preserved and diverse, and document serial changes in Late Pleistocene and Holocene plant zone distribution and composition in the westernmost Great Basin; they consist of taxa now inhabiting montane forest, woodland, steppe, and desert-scrub environments. The studied core intervals are interpreted here to be the terrestrial equivalent of marine ?18O stages 1 through 9; these pollen profiles now appear to be among the best radiometrically dated Late Pleistocene records of terrestrial climate change known.
Litwin, Ronald J.; Smoot, Joseph P.; Durika, Nancy J.; Smith, George I.
Radiometric Dating and Heavy Metal Content of A Recent Sediment Core from Lake Trenntsee in Northeastern Germany
A sediment core from Lake Trenntsee in northeastern Germany was dated radiometrically to gain a chronology of the observed depth profiles of heavy metal concentration. The chronology was based on gammaspectrometric measurements of fallout nuclides and Pb dating. Fallout from the Chernobyl reactor accident could be distinguished from the one of nuclear bomb testing by means of Cs data and
A. Suckow; H. E. G�bler
Dating techniques in archaeology and paleoanthropology
Archaeologists have an increasing array of physical dating methods at their disposal. R.E. Taylor of the University of California discusses available techniques, recent advances in radiocarbon dating, and current developments in radiocalcium dating.
Taylor, R.E.
Radiometric Dating of Ochoan (Permian) Evaporites, WIPP (Waste Isolation Pilot Plant) Site, Delaware Basin, New Mexico, USA.
National Technical Information Service (NTIS)
We have attempted radiometric dating of halide-sulfate salts and clay minerals from the Delaware Basin, New Mexico, USA, as part of geochemical study of the stability of the evaporite sequence at the WIPP (Waste Isolation Pilot Plant - a US DOE facilty) s...
D. G. Brookins S. J. Lambert
Statistical techniques applied to aerial radiometric surveys (STAARS): time series analysis of airborne radiometric data. National Uranium Resource Evaluation
Airborne radiometric data are often used in reconnaissance for minerals with radiologic isotopes present. The US Department of Energy, through the National Uranium Resource Evaluation (NURE) program, has conducted extensive airborne radiometric surveys over parts of the United States to assist in the location of potentially profitable mineral deposits. In this paper techniques useful in the analysis of these survey data are presented. This paper presents the concept of linearly certain point processes. This concept unifies and extends several previously published models for airborne radiometric data. The concept of filtering a point process together with the model for the process can then be used to derive the matched filter to optimally extract the ground level concentration information from the airborne data. Several additional topics are also discussed. The first is how the airborne data may be used to enhance design of ground-based experiments and measurements. Next, concepts of multivariate time series are developed to show how several energy bands can be optimally used to estimate the concentration of a single isotope using time series regression methods. Finally, time series principal components are used to gain better signal-to-noise properties than are typically obtained with the use of traditional principal components.
Davis, H.T.
Radiometric dating of Ochoan (Permian) evaporites, WIPP (Waste Isolation Pilot Plant) site, Delaware Basin, New Mexico, USA
We have attempted radiometric dating of halide-sulfate salts and clay minerals from the Delaware Basin, New Mexico, USA, as part of geochemical study of the stability of the evaporite sequence at the WIPP (Waste Isolation Pilot Plant - a US DOE facilty) site. We undertook this dating to determine: (1) primary age of evaporite genesis or time(s) of recrystallization; (2) if previously undated evaporite minerals (leonite, polyhalite, kieserite) give useful data; and (3) if the detrital clay minerals have been radiometrically reset at any time following their incorporation into the evaporite medium. We have shown earlier that polyhalites can indeed be successfully dated by the K-Ar method, and once corrections are applied for admixed halide minerals, dates of 210-230 Ma for the Delaware Basin are obtained. Rb-Sr isochrons from early stage sylvites-polyhalites- anhydrites yield 220 +- 10 Ma, even when some sylvites yield lower K-Ar dates due to loss of *40-Ar. K-Ar dates on leonites and kieserities are also low due to *40-Ar loss, but their Rb-Sr dates are higher. Detrital clay minerals from the Delaware Basin collectively yield a highly scattered isochron (390 +- 77 Ma), but samples from a local area, such as the WIPP Site, give a much better age of 428 +- 7 Ma. These dates show that the interaction between the clay minerals and the evaporitic brines was insufficient to reset the clay minerals Rb-Sr systematics. In a related study, we note that a dike emplaced into the evaporite at 34 Ma had only very limited effect on the intruded rocks; contact phenomena were all within 2 m of the dike. All of our geochemical (radio-metric and trace element) studies of the WIPP site argue for preservation of the isotopic and chemical integrity of the major minerals for the past 200 Ma.
Brookins, D.G.; Lambert, S.J.
Radiometrically determined dates and sedimentation rates for recent sediments in nine North African wetland lakes (the CASSARINA Project)
Sediment cores were collected from nine wetland lakes in Morocco, Tunisia and Egypt for the CASSARINA project investigating environmental change in Northern African wetlands. The cores were dated radiometrically by using natural (210Pb) and artificial (137Cs and 241Am) radionuclides. At sites in Morocco and Tunisia with mean annual rainfall totals ranging from 500�1000 mm yr-1, fallout records were generally satisfactory
P. G. Appleby; H. H. Birks; R. J. Flower; N. Rose; S. M. Peglar; M. Ramdani; M. M. Kra�em; A. A. Fathi
Radiometric dating (210Pb, 137Cs, 241Am) of recent ombrotrophic peat accumulation and evidence for changes in mass balance
The paper summarizes and evaluates the results of 210Pb, 137Cs and 241Am analysis on 37 recent ombrotrophic peat profiles. From these and previously published data, it is concluded that radiometric measurements alone cannot be relied on to give an accurate chronology of peat accumulation. Where constrained by profiles of 241Am activity in the upper part and one or more pollen-dated
F. Oldfield; N. Richardson; P. G. Appleby
Radiometric dating of the type-site for Homo heidelbergensis at Mauer, Germany
The Mauer mandible, holotype of Homo heidelbergensis, was found in 1907 in fluvial sands deposited by the Neckar River 10 km southeast of Heidelberg, Germany. The fossil is an important key to understanding early human occupation of Europe north of the Alps. Given the associated mammal fauna and the geological context, the find layer has been placed in the early Middle Pleistocene, but confirmatory chronometric evidence has hitherto been missing. Here we show that two independent techniques, the combined electron spin resonance/U-series method used with mammal teeth and infrared radiofluorescence applied to sand grains, date the type-site of Homo heidelbergensis at Mauer to 609 � 40 ka. This result demonstrates that the mandible is the oldest hominin fossil reported to date from central and northern Europe and raises questions concerning the phyletic relationship of Homo heidelbergensis to more ancient populations documented from southern Europe and in Africa. We address the paleoanthropological significance of the Mauer jaw in light of this dating evidence.
Wagner, Gunther A.; Krbetschek, Matthias; Degering, Detlev; Bahain, Jean-Jacques; Shao, Qingfeng; Falgueres, Christophe; Voinchet, Pierre; Dolo, Jean-Michel; Garcia, Tristan; Rightmire, G. Philip
Radiometric dating of the Earlier Stone Age sequence in excavation I at Wonderwerk Cave, South Africa: preliminary results.
We present here the results of 44 paleomagnetic measurements, and single cosmogenic burial and optically stimulated luminescence ages for the Earlier Stone Age deposits from Wonderwerk Cave, Northern Cape, South Africa. The resulting paleomagnetic sequence: N>R>N>R>N constrains the Earlier Stone Age strata in this part of the site to between approximately 0.78-1.96 Ma. A single cosmogenic date of approximately 2.0 Ma from the base of the section offers some corroboration for the paleomagnetic sequence. Preliminary results indicate that the small lithic assemblage from the basal stratum may contain an Oldowan facies. This is overlain by several strata containing Acheulean industries. The preliminary radiometric dates reported here place the onset of the Acheulean at this site to approximately 1.6 Ma, which is roughly contemporaneous with that of East Africa. PMID:18501953
Chazan, Michael; Ron, Hagai; Matmon, Ari; Porat, Naomi; Goldberg, Paul; Yates, Royden; Avery, Margaret; Sumner, Alexandra; Horwitz, Liora Kolska
Artifact correction and absolute radiometric calibration techniques employed in the Landsat 7 image assessment system
The Landsat-7 Image Assessment System (IAS), part of the Landsat-7 Ground System, will calibrate and evaluate the radiometric and geometric performance of the Enhanced Thematic Mapper Plus (ETM +) instrument. The IAS incorporates new instrument radiometric artifact correction and absolute radiometric calibration techniques which overcome some limitations to calibration accuracy inherent in historical calibration methods. Knowledge of ETM + instrument characteristics gleaned from analysis of archival Thematic Mapper in-flight data and from ETM + prelaunch tests allow the determination and quantification of the sources of instrument artifacts. This a priori knowledge will be utilized in IAS algorithms designed to minimize the effects of the noise sources before calibration, in both ETM + image and calibration data.
Boncyk, Wayne, C.; Markham, Brian, L.; Barker, John, L.; Helder, Dennis
Geochronological correlation of the main coal interval in Brazilian Lower Permian: Radiometric dating of tonstein and calibration of biostratigraphic framework
NASA Astrophysics Data System (ADS)
The radiometric age of 291 � 1.2 Ma obtained through single-crystal zircon U-Pb ages (Sensitive High Resolution Ion MicroProbe - SHRIMP II) of tonsteins from the Le�o-Buti� Coalfield, southern Paran� Basin (Rio Grande do Sul state), associated with previous SHRIMP II radiometric data obtained from tonsteins from the western (Candiota Coalfield) and eastern (Faxinal and Le�o-Buti� coalfields) borders of the basin indicate that the mean age of the main peat-forming interval is 291.0 � 1.3 Ma. In a regional context, the mean age represents a consistent geochronological correlation for the uppermost and more important coal seams in southern Brazilian coalfields, but this assumption does not establish an ash fall origin from a single volcanic event. According to the International Stratigraphic Chart, the interval is dated as middle Sakmarian. The coal palynofloras are included in the Protohaploxypinus goraiensis Subzone within the palynostratigraphic framework for the Brazilian Paran� Basin. Formal relationships are also established with the Glossopteris-Rhodeopteridium Zone within the phytostratigraphic chart for the Lower Permian of southern Brazilian Paran� Basin.
Simas, Margarete Wagner; Guerra-Sommer, Margot; Cazzulo-Klepzig, Miriam; Menegat, Rualdo; Schneider Santos, Jo�o Orestes; Fonseca Ferreira, Jos� Alcides; Degani-Schmidt, Isabela
Towards a Stacked 1 Ma-year Radiometrically Dated Palaeoclimate Record From Italian Speleothems
Stable isotope patterns from precisely dated Late Pleistocene speleothems from Corchia Cave (Italy) record orbital- and millennial-scale variations in North Atlantic circulation. Recent developments in uranium-lead (U- Pb) dating make it possible to extend the speleothem record from this cave beyond 0.5 Ma. The cave's speleothems are ideal for U-Pb dating because of their low detrital content, high uranium concentrations
R. Drysdale; J. Hellstrom; W. Jon; I. Couchoud; G. Zanchetta; C. Spoetl; A. Fallick; A. Greig; I. Isola
New UPb radiometric dates of the Bear Mountain intrusive complex, Klamath Mountains, California
New, high-precision U-Pb titanite (sphene) and zircon dates from five samples of the Bear Mountain intrusive complex establish the timing and duration of magma- tism. The oldest, magmatic date (150.5 � 0.6 Ma) comes from dark-colored titanite from a biotite-hornblende tonalite that is part of a composite pluton that intrudes the Blue Ridge ultramafic-gabbroic intrusion. Pale titanite and zircon from
Kevin R. Chamberlain; Arthur W. Snoke; Calvin G. Barnes; Jonathan C. Bushey
Radiometric Dating of Ignimbrite from Inner Mongolia Provides no Indication of a Post-Middle Jurassic Age for the Daohugou Beds
Lacustrine deposits exposed at Daohugou, Inner Mongolia, China, have yielded superbly preserved vertebrate fossils. The fossil beds were first misinterpreted as of Early Cretaceous age, based on alleged occurrences of key fossils of the Jehol Biota. Compelling evidence revealed by more rigorous research involving regional biostratigraphy, radiometric dating, and paleontology supports the Middle Jurassic age of the fossil beds. Despite
GAO Ke-Qin; REN Dong
Radiometric dating of Tasmanian speleothems - evidence of cave evolution and climatic change
Th\\/U dates on Tasmanian speleothems enable preliminary estimates to be made of ages and rates of evolution of Tasmanian karst caves. Occurrence of speleothem deposition has varied markedly in time, the highest abundance being associated with marine isotope stages 1 and 5. Rates of growth of from 21 to 79 mm\\/ka have been determined for four equilibrium diameter stalagmites, some
A. Goede; R. S. Harmon
Radiometric dating of quaternary deposits and the hominid mandible of lake banyolas, Spain
We report results of U-series analyses of the travertine matrix surrounding the Banyolas mandible that indicate an age of 45??4 ka bp. The mandible, an archaic hominid fossil generally deemed of mid-Pleistocene age, was recovered from a travertine matrix in 1887. Similar analyses on 21 travertine samples from quarries near the discovery site yield coherent U-series dates in correct stratigraphic order, ranging from 44 ka bp to 117 ka bp. Isotopic composition of these samples and the mandible matrix show no evidence of open system behaviour. Coherent isotopic results from adjacent quarries support the validity of the date on the mandible travertine, and we conclude the mandible is much younger than previously believed. ?? 1991.
Julia, R.; Bischoff, J. L.
Teaching radioactive decay & radiometric dating: an analog activity based on fluid dynamics
NSDL National Science Digital Library
A fluid flowing from an upper beaker into a lower beaker (shampoo in this case) behaves mathematically identically to radioactive decay, mimicking the exponential decay process, dependent on the amount of fluid in the upper beaker (representing the amount of parent isotopes) and the size of the hole in the beaker (representing the decay constant). Students measure the fluid depth with time for several "runs" with varied conditions, then graph their results, create decay equations, manipulate these equations and use them to "date" another experiment. They then apply their new understanding to make predictions regarding complications involved in the decay process and its use in dating (such as daughter loss). Developed by Lily Claiborne and Calvin Miller.
Grundstrom, Erika
Antiquity of man in America indicated by radiometric dates on the Yuha burial site
MUCH evidence suggests that man was present in the Western Hemisphere before 12,000 yr ago, but the case has remained less than conclusive1. In some situations, the geological age of the site is reasonably well established but the association or nature of the artefacts is questionable2,3. In other cases, museum specimens of human bones dated by radiocarbon analysis of collagen
James L. Bischoff; Richard Merriam; W. MORLIN CHILDERS; REINER PROTSCH
Direct Radiometric Dating of Hydrocarbon Deposits Using Rhenium-Osmium Isotopes
Rhenium-osmium (Re-Os) data from migrated hydrocarbons establish the timing of petroleum emplacement for the giant oil sand deposits of Alberta, Canada, at 112 +\\/- 5.3 million years ago. This date does not support models that invoke oil generation and migration for these deposits in the Late Cretaceous. Most Re-Os data from a variety of deposits within the giant hydrocarbon system
David Selby; Robert A. Creaser
Radiometric dates for the Middle Palaeolithic sequence of Payre (Ard�che, France)
The archaeological site of Payre (France) yielded Middle Palaeolithic layers with Neanderthal remains, which are partly bracketed by two stalagmitic flowstones. To obtain a precise chronological framework for the human occupation and the faunal remains of this site, several dating methods were used: uranium-series (U-series by alpha spectrometry and TIMS) and electron spin resonance (ESR) on stalagmitic flowstones, combined ESR\\/U-series
H. Valladas; N. Mercier; L. K. Ayliffe; C. Falgu�res; J.-J. Bahain; J.-M. Dolo; L. Froget; J.-L. Joron; H. Masaoudi; J.-L. Reyss; M.-H. Moncel
Potential drug targets for Mycobacterium avium defined by radiometric drug-inhibitor combination techniques.
Previously established radiometric techniques were used to assess the effectiveness of combined antimicrobial drug-inhibitory drug (drug-inhibitor) treatment on two clinical isolates of the Mycobacterium avium complex representing three colony variants: smooth opaque (dome) (SmO), smooth transparent (SmT), and rough (Rg). All variants were identified as members of the M. avium complex; however, only the SmT colony type of strain 373 possessed characteristic serovar-specific glycopeptidolipid (GPL) antigens. MICs, determined radiometrically, of drugs with the potential to inhibit the biosynthesis of GPL antigens or other cell envelope constituents were similar for all strains. These drugs included cerulenin, N-carbamyl-DL-phenylalanine, N-carbamyl-L-isoleucine, trans-cinnamic acid, ethambutol, 1-fluoro-1-deoxy-beta-D-glucose, 2-deoxy-D-glucose, and m-fluoro-phenylalanine. The MICs of the antimicrobial drugs amikacin, sparfloxacin, and clarithromycin varied, but overall the MICs for the SmO variant were the lowest. Radiometric assessment of drug-inhibitor combinations by using established x/y determinations revealed enhanced activity when either ethambutol or cerulenin were used in combination with all antimicrobial agents for all variants except the Rg variant of strain 424, for which ethambutol was not effective. Enhanced activity with amino acid analogs was observed with the Rg colony variants of strains 373 and 424. Two potential sites for drug targeting were identified: fatty acid synthesis, for all strains assayed, and peptide biosynthesis, particularly for Rg colony variants that possess previously identified phenylalanine-containing lipopeptides as potential targets for future drug development. Images
Rastogi, N; Goh, K S; Wright, E L; Barrow, W W
Geochronological data from the Faxinal coal succession, southern Paran� Basin, Brazil: A preliminary approach combining radiometric UPb dating and palynostratigraphy
A radiometric zircon age of 285.4�8.6Ma (IDTIMS U-Pb) is reported from a tonstein layer interbedded with coal seams in the Faxinal coalfield, Rio Grande do Sul, Brazil. Calibration of palynostratigraphic data with the absolute age shows that the coal depositional interval in the southern Paran� Basin is constrained to the Sakmarian. Consequently, the basal Gondwana sequence in the southern part
Margot Guerra-Sommer; Miriam Cazzulo-Klepzig; Rualdo Menegat; Milton Luiz Laquintinie Formoso; Miguel �ngelo Stipp Basei; Eduardo Guimar�es Barboza; Margarete Wagner Simas
Lamprophyre dyke suites from western Tasmania, their radiometric dating and the age of thrust faulting in the Point Hibbs area
Six radiometric age determinations from minettes in lamprophyre dyke suites from western Tasmania give Late Devonian ages (range: 366�377 Ma; weighted average 373.4�14.1 Ma). In the Point Hibbs area this result tightly constrains the age of a significant period of northwestward?directed thrust faulting which postdated the Lower Devonian (Pragian) Point Hibbs Formation but predated the dykes. This period of faulting
M. P. McClenaghan; D. B. Seymour; I. M. Villa
Transferring radiometric dating of the last interglacial sea level high stand to marine and ice core records
In order to derive a radiometric age marker for the end of the penultimate glacial�interglacial transition, we compiled published U-series isotope measurements on corals from the period extending from stage 6 to the middle of the last interglacial, and computed the corresponding open-system ages using Thompson et al. model (Thompson, W.G., Spiegelman, M.W., Goldstein, S.L., Speed, R.C., An open-system model
C. Waelbroeck; N. Frank; J. Jouzel; F. Parrenin; V. Masson-Delmotte; D. Genty
Direct radiometric dating of the Devonian-Mississippian time-scale boundary using the Re-Os black shale geochronometer
Many Phanerozoic time-scale boundaries are characterized by oceanic anoxia and mass extinction events with the deposition of black shale. The Re-Os isotope system in black shale can be used to provide depositional ages for these rocks, thus yielding direct radiometric ages for time-scale boundaries. We demonstrate that the Re-Os black shale geochronometer can yield precise ages useful for time-scale research
David Selby; Robert A. Creaser
Remote sensing of row crop structure and component temperatures using directional radiometric temperatures and inversion techniques
NASA Technical Reports Server (NTRS)
A physically based sensor response model of a row crop was used as the mathematical framework from which several inversion strategies were tested for extracting row structure information and component temperatures using a series of sensor view angles. The technique was evaluated on ground-based radiometric thermal infrared data of a cotton row crop that covered 48 percent of the ground in the vertical projection. The results showed that the accuracies of the predicted row heights and widths, vegetation temperatures, and soil temperatures of the cotton row crop were on the order of 5 cm, 1 deg, and 2 deg C, respectively. The inversion techniques can be applied to directional sensor data from aircraft platforms and even space platforms if the effects of atmospheric absorption and emission can be corrected. In theory, such inversion techniques can be applied to a wide variety of vegetation types and thus can have significant implications for remote sensing research and applications in disciplines that deal with incomplete vegetation canopies.
Kimes, D. S.
Statistical Techniques Applied to Aerial Radiometric Surveys (STAARS): Cluster Analysis. National Uranium Resource Evaluation.
National Technical Information Service (NTIS)
One objective of the aerial radiometric surveys flown as part of the US Department of Energy's National Uranium Resource Evaluation (NURE) program was to ascertain the regional distribution of near-surface radioelement abundances. Some method for identify...
F. L. Pirkle N. K. Stablein J. A. Howell G. W. Wecksung B. S. Duran
Clinical laboratory comparison of lysis-centrifugation and BACTEC radiometric blood culture techniques.
The lysis-centrifugation technique (ISOLATOR; E. I. du Pont de Nemours & Co., Wilmington, Del.) and the radiometric blood culture technique (BACTEC; Johnston Laboratories, Inc., Cockeysville, Md.) were compared on 1,000 blood cultures. A total of 16 ml of blood was distributed: 8 ml into an ISOLATOR 7.5 microbial tube and 4 ml each into BACTEC 7C and 8B bottles. The concentrate from the ISOLATOR tubes was inoculated under a laminar-flow hood onto two sheep blood agar plates (one incubated in CO2 and one incubated anaerobically), one chocolate agar plate, and one brain heart infusion agar plate. Of 91 blood specimens obtained that yielded clinically significant organisms, 52 were positive by both systems, 27 were positive by the ISOLATOR system only, and 12 were positive by the BACTEC system only. From the positive blood specimens, 97 clinically significant organisms were isolated: 57 by both systems, 27 by the ISOLATOR system only, and 13 by the BACTEC system only. Of the 57 organisms detected by both systems, 28 were detected simultaneously, 13 were detected earlier by the ISOLATOR system, and 16 were detected earlier by the BACTEC system. Isolated colonies were obtained earlier by the ISOLATOR system in 40 cases and by the BACTEC system in 5 cases. Organisms determined to be contaminants by thorough chart review were isolated from 138 ISOLATOR tubes. In 98 instances, these were represented by one colony of Staphylococcus epidermidis, alpha-hemolytic streptococci, or diphtheroids. The ability to determine CFU per milliliter with the ISOLATOR system did not help differentiate clinically significant organisms from contaminants. PMID:6358246
McLaughlin, J C; Hamilton, P; Scholes, J V; Bartlett, R C
Clinical laboratory comparison of lysis-centrifugation and BACTEC radiometric blood culture techniques.
The lysis-centrifugation technique (ISOLATOR; E. I. du Pont de Nemours & Co., Wilmington, Del.) and the radiometric blood culture technique (BACTEC; Johnston Laboratories, Inc., Cockeysville, Md.) were compared on 1,000 blood cultures. A total of 16 ml of blood was distributed: 8 ml into an ISOLATOR 7.5 microbial tube and 4 ml each into BACTEC 7C and 8B bottles. The concentrate from the ISOLATOR tubes was inoculated under a laminar-flow hood onto two sheep blood agar plates (one incubated in CO2 and one incubated anaerobically), one chocolate agar plate, and one brain heart infusion agar plate. Of 91 blood specimens obtained that yielded clinically significant organisms, 52 were positive by both systems, 27 were positive by the ISOLATOR system only, and 12 were positive by the BACTEC system only. From the positive blood specimens, 97 clinically significant organisms were isolated: 57 by both systems, 27 by the ISOLATOR system only, and 13 by the BACTEC system only. Of the 57 organisms detected by both systems, 28 were detected simultaneously, 13 were detected earlier by the ISOLATOR system, and 16 were detected earlier by the BACTEC system. Isolated colonies were obtained earlier by the ISOLATOR system in 40 cases and by the BACTEC system in 5 cases. Organisms determined to be contaminants by thorough chart review were isolated from 138 ISOLATOR tubes. In 98 instances, these were represented by one colony of Staphylococcus epidermidis, alpha-hemolytic streptococci, or diphtheroids. The ability to determine CFU per milliliter with the ISOLATOR system did not help differentiate clinically significant organisms from contaminants.
McLaughlin, J C; Hamilton, P; Scholes, J V; Bartlett, R C
Multi-method radiometric dating of volcano-sedimentary layers from northern Italy: Age and duration of the Priabonian stage
A comparison between conventional K-Ar (biotite) ages and fission track (zircon and apatite) and U-Pb (zircon) ages obtained from stratigraphically well-constrained Priabonian (Late Eocene) volcano-sedimentary deposits of northern Italy is presented. Two sections at Priabona (one level) and Possagno (two levels) were dated. The application of fission track dating appears fruitful for obtaining reasonably precise (+\\/-4 to 5% 2sigma errors)
G. S. Odin; V. Barbin; A. J. Hurford; H. Baadsgaard; B. Galbrun; P.-Y. Gillot
Surface dating of bricks, an application of luminescence techniques
NASA Astrophysics Data System (ADS)
Luminescence techniques are a powerful tool to date archaeological ceramic materials and geological sediments. Thermoluminescence (TL) is widely used for bricks dating to reconstruct the chronology of urban complexes and the development of human cultures. However, it can sometimes be inconclusive, since TL assesses the firing period of bricks, which can be reused, even several centuries later. This problem can be circumvented using a dating technique based on a resetting event different from the last heating. OSL (Optically Stimulated Luminescence) exploits the last light exposition of the brick surface, which resets the light-sensitive electron traps until the surface is definitely shielded by mortar and superimposed bricks. This advanced application (surface dating) has been successfully attempted on rocks, marble and stone artifacts, but not yet on bricks. A recent conservation campaign at the Certosa di Pavia gave the opportunity to sample some bricks belonging to a XVII century collapsed wall, still tied to their mortars. This was an advantageous condition to test this technique, comparing the dating results with precise historical data. This attempt gave satisfactory results, allowing to identify bricks surely reused and to fully confirm that the edification of the perimetral wall occurred at the end of XVII century.
Galli, Anna; Martini, Marco; Maspero, Francesco; Panzeri, Laura; Sibilia, Emanuela
Radiometric correction procedure study
NASA Technical Reports Server (NTRS)
A comparison of MSS radiometric processing techniques identified as a preferred radiometric processing technique a procedure which equalizes the mean and standard deviation of detector-specific histograms of uncalibrated scene data. Evaluation of MSS calibration data demonstrated that the relationship between detector responses is essentially linear over the range of intensities typically observed in MSS data, and that the calibration wedge data possess a high degree of temporal stability. An analysis of the preferred radiometric processing technique showed that it could be incorporated into the MDP-MSS system without a major redesign of the system, and with minimal impact on system throughput.
Colby, C.; Sands, R.; Murphrey, S.
The Sima de los Huesos Hominids Date to Beyond U\\/Th Equilibrium (>350 kyr) and Perhaps to 400�500 kyr: New Radiometric Dates
The Sima de los Huesos site of the Atapuerca complex near Burgos, Spain contains the skeletal remains of at least 28 individuals in a mud breccia underlying an accumulation of the Middle Pleistocene cave bear (U. deningeri). Earlier dating estimates of 200 to 320kyr were based on U-series and ESR methods applied to bones, made inaccurate by unquantifiable uranium cycling.
James L. Bischoff; Donald D. Shamp; Arantza Aramburu; Juan Luis Arsuaga; Eudald Carbonell; J. M. Bermudez de Castro
Radiometric dates of uplifted marine fauna in Greece: Implications for the interpretation of recent earthquake and tectonic histories using lithophagid dates
In AD 365 a great (Mw>8) earthquake lifted up western Crete, exposing a shoreline encrusted by marine organisms, and up to 10m of marine substrate beneath it. Radiocarbon ages determined for corals and bryozoans exposed between the paleo-shoreline and present sea level are consistent, within measurement error, with each other and with the date of the earthquake. But radiocarbon ages
B. Shaw; J. A. Jackson; T. F. G. Higham; P. C. England; A. L. Thomas
Radiometric dates of uplifted marine fauna in Greece: Implications for the interpretation of recent earthquake and tectonic histories using lithophagid dates
In AD 365 a great (Mw > 8) earthquake lifted up western Crete, exposing a shoreline encrusted by marine organisms, and up to 10 m of marine substrate beneath it. Radiocarbon ages determined for corals and bryozoans exposed between the paleo-shoreline and present sea level are consistent, within measurement error, with each other and with the date of the earthquake.
B. Shaw; J. A. Jackson; T. F. G. Higham; P. C. England; A. L. Thomas
Initial Radiometric Calibration of the AWiFS using Vicarious Calibration Techniques
NASA Technical Reports Server (NTRS)
NASA SSC maintains four ASD FieldSpec FR spectroradiometers: 1) Laboratory transfer radiometers; 2) Ground surface reflectance for V&V field collection activities. Radiometric Calibration consists of a NIST-calibrated integrating sphere which serves as a source with known spectral radiance. Spectral Calibration consists of a laser and pen lamp illumination of integrating sphere. Environmental Testing includes temperature stability tests performed in environmental chamber.
Pagnutti, Mary; Thome, Kurtis; Aaron, David; Leigh, Larry
The Sima de los Huesos hominids date to beyond U/Th equilibrium (>350 kyr) and perhaps to 400-500 kyr: New radiometric dates
The Sima de los Huesos site of the Atapuerca complex near Burgos, Spain contains the skeletal remains of at least 28 individuals in a mud breccia underlying an accumulation of the Middle Pleistocene cave bear (U. deningeri). Earlier dating estimates of 200 to 320 kyr were based on U-series and ESR methods applied to bones, made inaccurate by unquantifiable uranium cycling. We report here on a new discovery within the Sima de los Huesos of human bones stratigraphically underlying an in situ speleothem. U-series analyses of the speleothem shows the lower part to be at isotopic U/Th equilibrium, translating to a firm lower limit of 350 kyr for the SH hominids. Finite dates on the upper part suggest a speleothem growth rate of c. 1 cm/32 kyr. This rate, along with paleontological constraints, place the likely age of the hominids in the interval of 400 to 600 kyr. ?? 2002 Elsevier Science Ltd. All rights reserved.
Bischoff, J. L.; Shamp, D. D.; Aramburu, A.; Arsuaga, J. L.; Carbonell, E.; Bermudez, de, Castro, J. M.
Radiometric Calibration of the AWiFS Using Vicarious Calibration Techniques
NASA Technical Reports Server (NTRS)
A radiometric calibration assessment of the AWiFS (Advanced Wide Field Sensor) on the Indian Remote Sensing Resourcesat-1 satellite was performed by the NASA Applied Research & Technology Project Office (formerly the Applied Sciences Directorate) at the John C. Stennis Space Center. A reflectance-based vicarious calibration approach, requiring ground-based measurements coincident with satellite acquisitions and radiative transfer calculations, was used to estimate at-sensor radiance. The AWiFS is a 4-band, multispectral, moderate-resolution (60 m) imaging sensor that operates in the visible through short-wave infrared spectrum and is currently being considered as a Landsat-like alternative. Several study sites near the Stennis Space Center that attempted to span the dynamic range of the sensor were employed. Satellite at-sensor radiance values were compared to those estimated to determine the sensor's radiometric accuracy. The results of this evaluation provide the user community with an independent assessment of the radiometric accuracy of AWiFS image products, which are commercially available through GeoEye. These results are an extension of an independent assessment made by the University of Arizona Remote Sensing Group, the South Dakota State University Satellite Calibration Group & Image Processing Lab, and the NASA Applied Sciences Directorate at the John C. Stennis Space Center the previous year.
Pagnutti, Mary; Holekamp, Kara
Ground-based radiometric calibration of the Landsat 8 Operational Land Imager (OLI) using in situ techniques
NASA Astrophysics Data System (ADS)
Landsat 8 was successfully launched from Vandenberg Air Force Base in California on 11 February 2013, and was placed into the orbit previously occupied by Landsat 5. Landsat 8 is the latest platform in the 40-year history of the Landsat series of satellites, and it contains two instruments that operate in the solar-reflective and the thermal infrared regimes. The Operational Land Imager (OLI) is a pushbroom sensor that contains eight multispectral bands ranging from 400-2300 nm, and one panchromatic band. The spatial resolution of the multispectral bands is 30 m, which is similar to previous Landsat sensors, and the panchromatic band has a 15-m spatial resolution, which is also similar to previous Landsat sensors. The 12-bit radiometric resolution of OLI improves upon the 8-bit resolution of the Enhanced Thematic Mapper Plus (ETM+) onboard Landsat 7. An important requirement for the Landsat program is the long-term radiometric continuity of its sensors. Ground-based vicarious techniques have been used for over 20 years to determine the absolute radiometric calibration of sensors that encompass a wide variety of spectral and spatial characteristics. This work presents the early radiometric calibration results of Landsat 8 OLI that were obtained using the traditional reflectance-based approach. University of Arizona personnel used five sites in Arizona, California, and Nevada to collect ground-based data. In addition, a unique set of in situ data were collected in March 2013, when Landsat 7 and Landsat 8 were observing the same site within minutes of each other. The tandem overfly schedule occurred while Landsat 8 was shifting to the WRS-2 orbital grid, and lasted only a few days. The ground-based data also include results obtained using the University of Arizona's Radiometric Calibration Test Site (RadCaTS), which is an automated suite of instruments located at Railroad Valley, Nevada. The results presented in this work include a comparison to the L1T at-sensor spectral radiance and the top-of-atmosphere reflectance, both of which are standard products available from the US Geological Survey.
Czapla-Myers, J.
Radiometric dating of sediment cores from a hydrothermal vent zone off Milos Island in the Aegean Sea
Sediment cores from a hydrothermal vent zone off Milos Island in the Aegean Sea were dated using the 210Pb method. The average unsupported 210Pb inventory in the cores was calculated to be 3256 Bq m?2. The corresponding mean annual 210Pb flux of 105 Bq m?2 year?1 is comparable to estimates of the atmospheric flux given in the literature. 210Pb fluxes
Aysun Ugur; Juan-Carlos Miquel; Scott W. Fowler; Peter Appleby
Radiometric dating of the Earlier Stone Age sequence in Excavation I at Wonderwerk Cave, South Africa: preliminary results
We present here the results of 44 paleomagnetic measurements, and single cosmogenic burial and optically stimulated luminescence ages for the Earlier Stone Age deposits from Wonderwerk Cave, Northern Cape, South Africa. The resulting paleomagnetic sequence: N>R>N>R>N constrains the Earlier Stone Age strata in this part of the site to between ?0.78�1.96Ma. A single cosmogenic date of ?2.0Ma from the base
Michael Chazan; Hagai Ron; Ari Matmon; Naomi Porat; Paul Goldberg; Royden Yates; Margaret Avery; Alexandra Sumner; Liora Kolska Horwitz
Uranium and thorium isotopes in minerals from the � Cetara � Serrara Fontana � tuff (Ischia Island, Italy) � A tentative radiometric dating
A cineritic level, which appears very interesting from a chronostratigraphic point of view because it is found throughout\\u000a the eastern Mediterranean Sea, has been related to the Cetara � Serrara Fontana tuff formation (Ischia Island, Italy)\\u000a by previous authors who estimated the age of this cineritic level to be about 25,000 years.\\u000a \\u000a A direct dating of the Cetara � Serrara
M. C. Delitala; C. Federici; A. Taddeucci
Modeling the Neutral-Atmosphere Propagation Delay in Radiometric Space Techniques
NASA Astrophysics Data System (ADS)
The propagation delay induced by the electrically-neutral atmosphere has been recognized as the most problematic modeling error for radiometric space geodetic techniques. A mismodeling of this propagation delay affects significantly the height component of position and constitutes therefore a matter of concern in space-geodesy applications, such as sea-level monitoring, postglacial rebound measurement, earthquake-hazard mitigation, and tectonic-plate-margin deformation studies. The neutral-atmosphere propagation delay is commonly considered as composed of two components: a ``hydrostatic'' component, due essentially to the dry gases of the atmosphere, and a ``non-hydrostatic'' component, due to water vapor. Each one can be described as the product of the delay at the zenith and a mapping function, which models the elevation angle dependence of the propagation delay. This dissertation discusses primarily the accuracy of zenith delay prediction models and mapping functions found in the scientific literature. This performance evaluation is based on a comparison against 32,467 benchmark values, obtained by ray tracing one-year's worth of radiosonde profiles from 50 stations distributed worldwide, and comprised different phases: ray-tracing accuracy assessment, model development, and model accuracy assessment. We have studied the sensitivity of the ray-tracing technique to the choice of physical models, processing strategies, and radiosonde instrumentation accuracy. We have concluded that errors in ray tracing can amount to a few centimetres, under special circumstances, but they largely average out for each station's time series of profiles. In order to optimize the performance of the models, we have established databases of the temperature-profile parameters using 50 additional sites, for a total of 100 radiosonde stations. Based on these large databases, we have developed models for lapse rate and tropopause height determination, which have improved significantly the performance of models using the information. From our model assessment we have concluded that the hydrostatic component of the zenith delay can be predicted with sub-millimeter accuracy, using the Saastamoinen model, provided accurate measurements of surface total pressure are available. The zenith non-hydrostatic component is much more difficult to predict from surface meteorological data or site dependent parameters, and the best models show values of root-mean-square (rms) scatter about the mean of a few centimetres in the zenith direction. Notwithstanding the large number of mapping functions we have analyzed, only a small group meet the high standards of modern space geodetic data analysis: Ifadis, Lanyi, MTT, and NMF. For the total number of radiosonde stations analyzed, none of the mapping functions revealed themselves to be superior for all elevation angles. For elevation angles above 15 degrees, Lanyi, MTT, and NMF yield identical mean biases and the best total error performances. At lower elevation angles, Ifadis and NMF are clearly superior. As regards the rms scatter about the mean, Ifadis performs the best for an elevation angles, followed closely by Lanyi.
Mendes, Virgilio De Brito
New twist on dating: radiocarbon dating techniques applied to air pollution studies
This paper deals with the problem of urban air pollution and to what extent it is caused by the burning of fossil fuels at factories or in cars, and to what extent it is due to the breathing processes of trees or the burning of natural fuels like wood. With the use of radiocarbon dating techniques the distinction between the pollutants can be made. The article describes the design of the gas proportional counter used to measure the extremely small samples of carbon in polluted air. (KRM)
Porter, G.
Inspection of an end quenched plain steel Jominy bar with photothermal radiometric techniques
NASA Astrophysics Data System (ADS)
The effect of the cooling rate on hardness and thermal conductivity in a metallurgical Jominy bar made of AISI 1018 steel, by means of a water end-quenched heat treatment process without diffusion-controlled case depth, is studied with photothermal radiometry (PTR). It is concluded that our two PTR techniques, common-mode rejection demodulation (CMRD) and conventional 50% duty-cycle square-wave frequency scan, are sensitive to low hardness values and gradients, unlike the high values all previous photothermal studies have dealt with to-date. Both PTR methods have yielded an anti-correlation between thermal conductivity and microhardness in this case as in previous cases with heat-treated and diffusion-controlled case depth profiles. It is shown that the cooling rate strongly affects both hardness and thermal conductivity in the Jominy-bar heat-treating process.
Liu, Y.; Baddour, N.; Mandelis, A.; Wang, C.
Chronology of Anthropogenic Heavy-Metal Fluxes and Pb Isotope Ratios Derived from Radiometrically Dated Lake Sediments in Northern Germany
Anthropogenic inventories and fluxes of Pb, Zn, Cu, and Sninto the sediments of two lakes, a drinking water reservoir(Neum�hler See) and an urban lake (Ziegelsee), both in ornear Schwerin, Germany, were investigated. A simplefreeze-coring technique was used for reproducible samplingof undisturbed surface sediments. Sediment chronology wasestablished for Ziegelsee by gamma spectrometry of thenuclides 134Cs, 137Cs, 241Am, 214Pb,214Bi and 210Pb; bioturbation
Hans-Eike G�bler; Axel Suckow
A comparison of radiometric correction techniques in the evaluation of the relationship between LST and NDVI in Landsat imagery.
Atmospheric corrections for multi-temporal optical satellite images are necessary, especially in change detection analyses, such as normalized difference vegetation index (NDVI) rationing. Abrupt change detection analysis using remote-sensing techniques requires radiometric congruity and atmospheric correction to monitor terrestrial surfaces over time. Two atmospheric correction methods were used for this study: relative radiometric normalization and the simplified method for atmospheric correction (SMAC) in the solar spectrum. A multi-temporal data set consisting of two sets of Landsat images from the period between 1991 and 2002 of Penang Island, Malaysia, was used to compare NDVI maps, which were generated using the proposed atmospheric correction methods. Land surface temperature (LST) was retrieved using ATCOR3_T in PCI Geomatica 10.1 image processing software. Linear regression analysis was utilized to analyze the relationship between NDVI and LST. This study reveals that both of the proposed atmospheric correction methods yielded high accuracy through examination of the linear correlation coefficients. To check for the accuracy of the equation obtained through linear regression analysis for every single satellite image, 20 points were randomly chosen. The results showed that the SMAC method yielded a constant value (in terms of error) to predict the NDVI value from linear regression analysis-derived equation. The errors (average) from both proposed atmospheric correction methods were less than 10%. PMID:21755424
Tan, Kok Chooi; Lim, Hwee San; Matjafri, Mohd Zubir; Abdullah, Khiruddin
Statistical techniques applied to aerial radiometric surveys (STAARS): principal components analysis user's manual. [NURE program
A Principal Components Analysis (PCA) has been written to aid in the interpretation of multivariate aerial radiometric data collected by the US Department of Energy (DOE) under the National Uranium Resource Evaluation (NURE) program. The variations exhibited by these data have been reduced and classified into a number of linear combinations by using the PCA program. The PCA program then generates histograms and outlier maps of the individual variates. Black and white plots can be made on a Calcomp plotter by the application of follow-up programs. All programs referred to in this guide were written for a DEC-10. From this analysis a geologist may begin to interpret the data structure. Insight into geological processes underlying the data may be obtained.
Koch, C.D.; Pirkle, F.L.; Schmidt, J.S.
Application of paleomagnetic techniques for dating hydrocarbon migration events
Establishing a relationship between hydrocarbon migration and the precipitation of authigenic magnetite is important for the development of a method to date hydrocarbon migration using paleomagnetic techniques. Important evidence for the relationship comes from a study of light and dark-banded calcite speleothems that occur in Ordovician limestones in southern Oklahoma. The speleothems are Permian in age, based on interbedded fossils. The dark bands contain primary fluid inclusions filled with hydrocarbons that are not extensively biograded. They also possess over an order of magnitude stronger magnetization than light bands. Paleomagnetic and rock magnetic data indicate that the magnetization in the dark bands was acquired during the Early Permian and resides in magnetite. Spheres, interpreted to be authigenic magnetite, are also found in magnetic extracts from the dark calcite. The results from the light and dark bands suggest that chemical conditions created by the hydrocarbons caused precipitation of authigenic magnetite and acquisition of the associated chemical remanent magnetization.
Elmore, R.D.
Evolution of the geomagnetic field prior to the Matuyama-Brunhes transition: radiometric dating of a 820 ka excursion at La Palma
NASA Astrophysics Data System (ADS)
We present Cassignol technique K-Ar dating of lava flows from La Palma (Canary Islands, Spain) that bracket the Matuyama-Brunhes transition. An age of 821 +/- 13 ka obtained for a transitionally magnetized flow (LS118) provides the first volcanic evidence for a geomagnetic excursion occurring about 40 kyr prior to the transition. This interval has been successfully correlated with intensity minima present in high-resolution deep-sea records before the Matuyama-Brunhes transition. This study, along with the growing number of well-dated excursions reported for the Brunhes and Matuyama Chrons, shows that the occurrence of excursions is a common feature of the evolution of the geomagnetic field during stable polarity intervals. However, the presence of two successive excursional states within 40 kyr prior to the actual reversal, conjugated with moderate averaged palaeointensity in this interval as deduced from deep-sea records, could suggest that favorable conditions for the reversal to occur existed since about 820 ka. The present study highlights the importance of detailed chronological constraints for our understanding of the transition of the geomagnetic field from a stable polarity to a reversal state.
Quidelleur, X.; Carlut, J.; Gillot, P.-Y.; Soler, V.
Sun Photometer Laser and Lamp Based Radiometric Calibrations; Comparison with the Langley Technique and Implications on Remote Sensing
NASA Astrophysics Data System (ADS)
Satellite-based remote sensing of the earth is a valuable data source for biological and oceanic studies. However when using remote sensing, it is necessary to correct the measured signal for atmospheric effects. As aerosols play a major role in atmospheric scattering, correcting algorithms based on Aerosol Optical Thickness (AOT) data have been developed to describe the scattering of radiation by aerosols. AOT data are collected by filter radiometers measuring the solar irradiance. The AOT is then retrieved applying the Beer-Bouger-Lambert Law to those measurements. Two radiometers, called Satellite Validation for Marine Biology and Aerosol Determination (SimbadA), were calibrated in this study. These instruments measure the upwelling radiance from the ocean as well as the solar irradiance, providing information on both marine reflectance and AOT. The goals of this study were to calibrate the radiometers using independent methods, evaluate the uncertainties for each method, and assess the influence of the results in terms of the science requirements. The radiometers were calibrated in irradiance and radiance mode using a monochromatic, laser-illuminated integrating sphere, in radiance mode using two different lamp-illuminated integrating spheres, and in irradiance mode using the Langley technique. First, a limited characterization of the instrument was conducted. The instrument's temporal stability and its spectral out-of-band response were evaluated. The instrument was then calibrated in radiance mode using a laser-illuminated integrating sphere that overfilled its field of view (FOV). The absolute radiance responsivity from this calibration was compared to results from measurements of two calibrated lamp illuminated spheres. The first comparison, with the NIST portable radiometric source (NPR), was a validation as good agreement between the two methods has been reported in previous studies. The second comparison was with the Hardy sphere from the Goddard Space Flight Center (GSFC) of the National Aeronautics and Space Administration (NASA). In this comparison the NASA radiance scale was compared to NIST's. A disagreement was observed and will be discussed. Finally, an absolute irradiance responsivity calibration was performed with the laser based facility using a small integrating sphere that underfilled the instrument's FOV. This was done in order to do a comparison with the Langley technique, which is based on irradiance measurements. Using the absolute spectral responsivity obtained with the laser based calibration and a solar irradiance spectrum, the expected Top of the Atmosphere signal (V0) was determined and compared with the V0 obtained from the Langley calibration. Results will be presented and implications for derived AOT discussed.
Souaidia, N.; Pietras, C.; Brown, S. W.; Lykke, K. R.; Frouin, R.; Deschamps, P.; Fargion, G.; Johnson, B. C.
Teaching the Mathematics of Radioactive Dating.
ERIC Educational Resources Information Center
Describes a method used to teach the concept of radiometric dating using mathematical equations. Explores the lack of information in textbooks on how to solve radiometric dating problems using mathematical concepts. (SAH)
Shea, James H.
(25143) Itokawa: The power of radiometric techniques for the interpretation of remote thermal observations in the light of the Hayabusa rendezvous results*
NASA Astrophysics Data System (ADS)
The near-Earth asteroid (25143) Itokawa was characterized in great detail by the Japanese Hayabusa mission. We revisited the available thermal observations in the light of the true asteroid properties with the goal of evaluating the possibilities and limitations of thermal model techniques. In total, we used 25 published ground-based mid-infrared photometric observations and five so far unpublished measurements from the Japanese infrared astronomical satellite AKARI in combination with improved H-G values (absolute magnitude and slope parameter). Our thermophysical model (TPM) approach allowed us to determine correctly the sense of rotation, to estimate the thermal inertia and to derive robust effective size and albedo values by only using a simple spherical shape model. A more complex shape model, derived from light-curve inversion techniques, improved the quality of the predictions considerably and made the interpretation of the thermal light curve possible. The radiometrically derived effective diameter value agrees within 2% with the true Itokawa size value. The combination of our TPM and the final (25143) Itokawa in-situ shape model was then used as a benchmark for deriving and testing radiometric solutions. The consolidated value for the surface-averaged thermal inertia is ? = 700 � 200 J m-2 s-0.5 K-1. We found that even the high-resolution shape models still require additional small-scale roughness in order to explain the disk-integrated infrared measurements. Our description of the thermal effects as a function of wavelengths, phase angle, and rotational phase facilitates the planning of crucial thermal observations for sophisticated characterization of small bodies, including other potentially hazardous asteroids. Our analysis shows the power of radiometric techniques to derive the size, albedo, thermal inertia, and also spin-axis orientation from small sets of measurements at thermal infrared wavelengths.
M�ller, Thomas G.; Hasegawa, Sunao; Usui, Fumihiko
Radiometric dating of granitic rocks from the Central Bohemian Plutonic Complex (Czech Republic): constraints on the chronology of thermal and tectonic events along the Moldanubian-Barrandian boundary
Single-zircon dating by step-wise evaporation has established that successive granitic intrusions were emplaced in the Central Bohemian Plutonic Complex (CBPC) during a short time span of about 10 Ma. In agreement with field data, the Po��ry trondhjemite, emplaced early at 351 �11 Ma and subcontemporaneously with the S�zava granodiorite dated at 349 �12 Ma, was followed by the Blatn� granodiorite
Franti�ek V. Holub; Alain Cocherie; Philippe Rossi
Monitoring of pesticide residues in Riyadh dates by SFE, MSE, SFC, and GC techniques
In the present work, simple and rapid extraction and analysis techniques of insecticide (OCPs, OPPs, pyrethroids), fungicide, acaricide, and herbicide residues in three cultivars� of date fruits viz., Khalas, Sukkari, Nabout Seif and their seeds have been applied. The date cultivars were collected from eight local markets of Riyadh, KSA. The extraction of pesticide residues from the three varieties of
Mohamed H. EL-Saeid; Saleh A. AL-Dosari
Simplified Vicarious Radiometric Calibration
NASA Technical Reports Server (NTRS)
A measurement-based radiance estimation approach for vicarious radiometric calibration of spaceborne multispectral remote sensing systems has been developed. This simplified process eliminates the use of radiative transfer codes and reduces the number of atmospheric assumptions required to perform sensor calibrations. Like prior approaches, the simplified method involves the collection of ground truth data coincident with the overpass of the remote sensing system being calibrated, but this approach differs from the prior techniques in both the nature of the data collected and the manner in which the data are processed. In traditional vicarious radiometric calibration, ground truth data are gathered using ground-viewing spectroradiometers and one or more sun photometer( s), among other instruments, located at a ground target area. The measured data from the ground-based instruments are used in radiative transfer models to estimate the top-of-atmosphere (TOA) target radiances at the time of satellite overpass. These TOA radiances are compared with the satellite sensor readings to radiometrically calibrate the sensor. Traditional vicarious radiometric calibration methods require that an atmospheric model be defined such that the ground-based observations of solar transmission and diffuse-to-global ratios are in close agreement with the radiative transfer code estimation of these parameters. This process is labor-intensive and complex, and can be prone to errors. The errors can be compounded because of approximations in the model and inaccurate assumptions about the radiative coupling between the atmosphere and the terrain. The errors can increase the uncertainty of the TOA radiance estimates used to perform the radiometric calibration. In comparison, the simplified approach does not use atmospheric radiative transfer models and involves fewer assumptions concerning the radiative transfer properties of the atmosphere. This new technique uses two neighboring uniform ground target areas having different reflectance values. The target areas can be natural or artificial and must be large enough to minimize adjacent-pixel contamination effects. The radiative coupling between the atmosphere and the terrain needs to be approximately the same for the two targets. This condition can be met for relatively uniform backgrounds when the distance between the targets is within a few hundred meters. For each target area, the radiance leaving the ground in the direction of the satellite is measured with a radiometrically calibrated spectroradiometer. Using the radiance measurements from the two targets, atmospheric adjacency and atmospheric scattering effects can be subtracted, thereby eliminating many assumptions about the atmosphere and the radiative interaction between the atmosphere and the terrain. In addition, the radiometrically calibrated spectroradiometer can be used with a known reflectance target to estimate atmospheric transmission and diffuse- to-global ratios without the need for ancillary sun photometers. Several comparisons between the simplified method and traditional techniques were found to agree within a few percent. Hence, the simplified method reduces the overall complexity of performing vicarious calibrations and can serve as a method for validating traditional radiative transfer models
Stanley, Thomas; Ryan, Robert; Holekamp, Kara; Pagnutti, Mary
Range and effectiveness of the unspiked K-Ar technique constrained by cross calibration with 40Ar-39Ar dated quaternary lavas
NASA Astrophysics Data System (ADS)
The unspiked K-Ar dating method ("Cassignol" technique) can distinguish very small amounts of 40Ar* in late Quaternary lavas. Nevertheless, this particular technique, which is a sensitive and rapid dating method, relies on the basic assumptions of the 40K-40Ar chronometer. The Achilles' tendon of the method is that we cannot verify the isotopic composition of the initial argon trapped in the samples. In other terms, we must assume that, at the time of formation, the 40Ar-36Ar ratio of the sample was the modern atmospheric value (295.5). A direct comparison between the magnetic polarity of some dated samples and their radiometric ages, using the APTS reference framework, demonstrates that some unaltered groundmass samples may give erroneously old ages. These overestimations, for the most part, probably reflect excess argon. This problem is obvious for some lavas on Gran Canaria which recorded the Reunion event. In the same island, several K-Ar ages which are coherent with the magnetic polarity of the samples coincide with magnetic reversals or event boundaries. However, the inconsistencies observed between some samples and the APTS, suggest that these age determinations must be considered carefully, if they are to be used to update the GPTS. Combined K-Ar and 40Ar-39Ar experiments on multiple subsamples of groundmass separated from individual basaltic lava flows facilitates a comparison of the two techniques and provides examples of the complementary information provided by each. These experiments also confirm the effectiveness of the two techniques to date key events such as geomagnetic field reversals and climatic changes. Examples of our results from Quaternary lavas of Fuerteventura, Gran Canaria and from Patagonia, will demonstrate the effectiveness of this combined approach.
Guillou, H.; Scaillet, S.; Singer, B.; Perez Torrado, F. J.; Carracedo, J. C.
Luminescence dating of archaeometallurgical slag: use of the SAR technique for determination of the burial dose
NASA Astrophysics Data System (ADS)
The potential of using luminescence techniques to date metallurgical slag of archaeological origin has been investigated. Slag is an important residue from the metal smelting process and there is no technique currently available to directly date it. An attempt has been made to apply an optically stimulated luminescence (OSL) single-aliquot technique using quartz extracted from the slag matrix. A single-aliquot regeneration technique was used and preliminary results are encouraging in spite of problems encountered in the determination of the equivalent dose ( De) and apparent underestimation of the preliminary dates obtained. The results presented here were obtained from measurements on copper and iron slag from archaeological sites in Britain and Greece.
Gautier, Anna??g
NASA Technical Reports Server (NTRS)
TES is an infrared Fourier transform spectrometer on board the EOS-Aura spacecraft launched July 15, 2004. Improvements to the radiometric calibration and consequent assessment of radiometric accuracy have been on-going since launch.
Worden, H.; Sarkissian, E.; Bowman, K.; Fisher, B.; Rider, D.; Aumann, H. H.; Apolinski, M.; Debaca, R. C.; Gluck, S.; Madatyan, M.; McDuffie, J.; Tremblay, D.; Shephard, M.; Cady-Pereira, K.; Tobin, D.; Revercomb, H.
Who's on First: A Relative Dating Activity
NSDL National Science Digital Library
In this activity, students are introduced to sequencing and geologic time through relative dating techniques. Students begin by categorizing cards of nonsense words, then move on to cards with pictures of fossils. Once students begin to grasp "relative" dating, they can extend their knowledge of geologic time by exploring radiometric dating and developing a timeline of Earth's history. There is a teacher's guide to this activity with background information and templates to use for teaching about relative dating. There are also objectives, materials, procedure, and questions.
Assessing soil erosion and control factors by radiometric technique in the source region of the Yellow River, Tibetan Plateau
NASA Astrophysics Data System (ADS)
Measurements of 137Cs concentration in soils were made in a representative catchment to quantify erosion rates and identify the main factors involved in the erosion in the source region of the Yellow River in the Tibetan Plateau. In order to estimate erosion rates in terms of the main factors affecting soil loss, samples were collected taking into account the slope and vegetation cover along six selected transects within the Dari County catchment. The reference inventory for the area was established at a stable, well-preserved, site of small thickness (value of 2324 Bq�m- 2). All the sampling sites had been eroded and 137Cs inventories varied widely in the topsoil (14.87-25.56 Bq�kg- 1). The effective soil loss values were also highly variable (11.03-28.35 t�km- 1�yr- 1) in line with the vegetation cover change. The radiometric approach was useful in quantifying soil erosion rates and examining patterns of soil movement.
Wang, Yibo; Niu, Fujun; Wu, Qingbai; Gao, Zeyong
Radiometric ages of Tennessee rocks
This report compiles and summarizes all known radiometric age determinations based on bedrock samples from Tennessee. Data are available for 89 sites. Specimens record both igneous and metamorphic events ranging in age from 1.3 billion to 220 million years before present. Tennessee rocks have been dated by techniques that measure the results of four different kinds of radioactive decay: thorium-lead, uranium-lead, potassium-argon, and rubidium-strontium. Most determinations meet normal scientific standards for reliability. This study focuses on clarifying published data by bringing together geochemical, geological, and geographical information for each site. In addition to data on the age of bedrock samples, this study presents basic information on the ages of meteorites from Tennessee and on the ages of sediments and organic remains from Ice Age fossil sites and more recent archeological sites. While bedrock ages are the thrust of the report, other kinds of absolute age determinations are briefly discussed. 98 references, 11 figures, 3 tables.
Corgan, J.X.; Bradley, M.W.
Radiometric Dating of Folds: A new approach to determine the timing of deformation at shallow-crustal conditions, with examples from the Mexican Fold-Thrust Belt
NASA Astrophysics Data System (ADS)
We are developing a robust method to obtain absolute ages of folds that were formed at shallow crustal conditions. The method takes advantage of illite neocrystallization in folded, clay-bearing layers and the ability to obtain accurate retention and total gas ages from small size fractions using encapsulated Ar analysis, analogous to prior work on fault gouge dating. We illustrate our approach in folded Cretaceous shale-bentonitic layers that are interbedded with carbonates of the Zimap�n and the Tampico-Misantla cretaceous basins in central-eastern Mexico. Basinal carbonates were buried by syntectonic turbidites and inverted during the formation of the Mexican Fold-Thrust in the Late Cretaceous. Results were obtained from four chevron folds that are representative of different stages of deformation, burial/temperature conditions and location within this thin-skinned orogenic wedge: two from the Zimap�n Basin (Folds 1 and 2) in the west and two from the Tampico-Misantla Basin (Folds 3 and 4) in the east. Mineralogic compositions and variations in illite-polytypes, crystallite-size (CS) and Ar/Ar ages were obtained from size fractions in limbs and hinges of folded layers. Ar retention ages produce a folding age of ~81 Ma for Fold 1 and ~69 Ma for Fold 2, which are fully consistent with stratigraphic limits from syn-orogenic turbidities and observed overprinting events in the Mexican Fold-Thrust Belt. The total gas age of Fold 3, on the easternmost margin of the Tampico-Misantla Basin is similar to that of Fold 2, indicating that the second event is regional in scale. In addition to presenting a new, reliable method to constrain the timing of local deformation, we interpret folding and associated clay neo-mineralization in terms of the regional burial history, and localization and propagation of deformation within a heterogeneous orogenic wedge involving progressive deformation of two basins separated by a platform block.
Fitz Diaz, E.; van der Pluijm, B. A.
Implications of a saltmarsh chronology for the Severn Estuary based on independent lines of dating evidence
There has been much work done on metal trends in salt marsh sediment sequences, but relatively little on radiometric dating of these same deposits. Using the example of the Severn Estuary, southwest England, both of these techniques are used to demonstrate how temporal metal pollution trends can be spatially correlated throughout the estuary to provide a series of dated time
Peter W. French
Developing OSL Geological Dating Techniques for Use on Future Missions to Mars
NASA Technical Reports Server (NTRS)
The surface of Mars has been subject to aeolian, fluvial, and periglacial activity in the (relatively) recent past. Unfortunately, chronological dating of recent events on Mars is difficult as the errors associated with crater counting are comparable to younger ages (approx. 1 Ma). Consequently, techniques to quantify the ages of geological processes on Mars have become an important area of research. Optically stimulated luminescence (OSL) dating is one candidate technique for in-situ dating of the deposition of Martian surface sediments. This method can aid in developing a geological and climatic history of the last million years on Mars. The current paper addresses some of the challenges and progress associated with developing OSL as a viable in-situ dating technique for Mars. Some of the challenges include the mineral composition, the effectiveness of solar resetting under Martian conditions, the temperature regime, and determining the natural dose rate on Mars. All of these topics are currently under investigation, and some preliminary results are presented.
Blair, M. W.; Kalchgruber, R.; Deo, S.; McKeever, S. W. S.
40Ar/39Ar technique of KAr dating: a comparison with the conventional technique
K-Ar ages have been determined by the 40Ar/39Ar total fusion technique on 19 terrestrial samples whose conventional K-Ar ages range from 3.4 my to nearly 1700 my. Sample materials included biotite, muscovite, sanidine, adularia, plagioclase, hornblende, actinolite, alunite, dacite, and basalt. For 18 samples there are no significant differences at the 95% confidence level between the KAr ages obtained by these two techniques; for one sample the difference is 4.3% and is statistically significant. For the neutron doses used in these experiments (???4 ?? 1018 nvt) it appears that corrections for interfering Ca- and K-derived Ar isotopes can be made without significant loss of precision for samples with K/Ca > 1 as young as about 5 ?? 105 yr, and for samples with K/Ca < 1 as young as about 107 yr. For younger samples the combination of large atmospheric Ar corrections and large corrections for Ca- and K-derived Ar may make the precision of the 40Ar/39Ar technique less than that of the conventional technique unless the irradiation parameters are adjusted to minimize these corrections. ?? 1971.
Brent, Dalrymple, G.; Lanphere, M. A.
Using Melting Ice to Teach Radiometric Dating.
ERIC Educational Resources Information Center
Presented is an activity in which a mystery setting is used to motivate students to construct their own decay curves of melting ice used as an analogy to radioactive decay. Procedures, materials, apparatus, discussion topics, presentation, and thermodynamics are discussed. (CW)
Wise, Donald Underkofler
PV Solar Radiometric Measurements
Radiometric measurements performed by the PV Solar Radiometric Measurements Task support NREL{close_quote}s centers for Measurements and Characterization, Performance Engineering and Reliability, and Renewable Energy Resources. The task provides characterization, measurements, testing, designs, and analysis of radiometric instrumentation and data for the performance of PV cells, modules, and systems. We describe recent characterization of the radiometric performance of pyranometers deployed for PV system testing at the NREL Outdoor Test Facility (OTF) and improvements undertaken in NREL broadband radiometer characterization. Typical measurement and calibration issues with diode array spectroradiometers used for absolute spectral measurements applied to PV performance and characterization are discussed. {copyright} {ital 1997 American Institute of Physics.}
Myers, D.R.; Cannon, T.W. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)
The 40Ar/39Ar dating technique applied to planetary sciences
NASA Astrophysics Data System (ADS)
The 40Ar/39Ar technique is a powerful geochronological method that can help to unravel the evolution of the solar system. The 40Ar/39Ar system can not only record the timing of volcanic and metamorphic processes on asteroids and planets, it finds domain of predilection in dating impact events throughout the solar system. However, the 40Ar/39Ar method is a robust analytical technique if, and only if, the events to be dated are well understood and data are not over interpreted. Yet, too many 'ages' reported in the literature are still based on over-interpretation of perturbed age spectra which tends to blur the big picture. This presentation is centred on the most recent applications of the 40Ar/39Ar technique applied to planetary material and through several examples, will attempt to demonstrate the benefit of focusing on statistically robust data. For example, 40Ar/39Ar dating of volcanic events on the Moon suggests that volcanism was mostly concentrated between ca. 3.8 and 3.1 Ga but statistical filtering of the data allow identifying a few well-defined eruptive events. The study of lunar volcanism would also benefit from dating of volcanic spherules. Rigorous filtering of the 40Ar/39Ar age database of lunar melt breccias yielded concordant and ages with high precision for two major basins (i.e. Imbrium & Serenitatis) of the Moon. 40Ar/39Ar dating of lunar impact spherules recovered from four different sites and with high- and low-K compositions shows an increase of ages younger than 400 Ma suggesting a recent increase in the impact flux. The impact history of the LL parent body (bodies?) has yet to be well constrained but may mimic the LHB observed on the Moon, which would indicate that the LL parent body was quite large. 40Ar/39Ar dating (in progress) of grains from the asteroid Itokawa recovered by the japanese Hayabusa mission have the potential to constrain the formation history and exposure age of Itokawa and will allow us to compare the results with the impact history recorded by LL chondrites. Basaltic meteorites (HEDs) show a 40Ar/39Ar age range between 4.1 and 3.4 Ga, suggesting a diffuse LHB event; however, the spread of apparent ages may be a data interpretation artefact, as new solid plateau age data suggest that the bombardment by large asteroids might have occurred over a briefer period between 3.5 and 3.8 Ga.
Jourdan, F.
Radiometric assays for glycerol, glucose, and glycogen.
We have developed radiometric assays for small quantities of glycerol, glucose and glycogen, based on a technique described by Thorner and Paulus (1971, J. Biol. Chem. 246, 3885-3894) for the measurement of glycerokinase activity. In the glycerol assay, glycerol is phosphorylated with [32P]ATP and glycerokinase, residual [32P]ATP is hydrolyzed by heating in acid, and free [32P]phosphate is removed by precipitation with ammonium molybdate and triethylamine. Standard dose-response curves were linear from 50 to 3000 pmol glycerol with less than 3% SD in triplicate measurements. Of the substances tested for interference, only dihydroxyacetone gave a slight false positive signal at high concentration. When used to measure glycerol concentrations in serum and in media from incubated adipose tissue, the radiometric glycerol assay correlated well with a commonly used spectrophotometric assay. The radiometric glucose assay is similar to the glycerol assay, except that glucokinase is used instead of glycerokinase. Dose response was linear from 5 to 3000 pmol glucose with less than 3% SD in triplicate measurements. Glucosamine and N-acetylglucosamine gave false positive signals when equimolar to glucose. When glucose concentrations in serum were measured, the radiometric glucose assay agreed well with hexokinase/glucose-6-phosphate dehydrogenase (H/GDH)-based and glucose oxidase/H2O2-based glucose assays. The radiometric method for glycogen measurement incorporates previously described isolation and digestion techniques, followed by the radiometric assay of free glucose. When used to measure glycogen in mouse epididymal fat pads, the radiometric glycogen assay correlated well with the H/GDH-based glycogen assay. All three radiometric assays offer several practical advantages over spectral assays. PMID:2817333
Bradley, D C; Kaslow, H R
Radiometric assays for glycerol, glucose, and glycogen
We have developed radiometric assays for small quantities of glycerol, glucose and glycogen, based on a technique described by Thorner and Paulus for the measurement of glycerokinase activity. In the glycerol assay, glycerol is phosphorylated with (32P)ATP and glycerokinase, residual (32P)ATP is hydrolyzed by heating in acid, and free (32P)phosphate is removed by precipitation with ammonium molybdate and triethylamine. Standard dose-response curves were linear from 50 to 3000 pmol glycerol with less than 3% SD in triplicate measurements. Of the substances tested for interference, only dihydroxyacetone gave a slight false positive signal at high concentration. When used to measure glycerol concentrations in serum and in media from incubated adipose tissue, the radiometric glycerol assay correlated well with a commonly used spectrophotometric assay. The radiometric glucose assay is similar to the glycerol assay, except that glucokinase is used instead of glycerokinase. Dose response was linear from 5 to 3000 pmol glucose with less than 3% SD in triplicate measurements. Glucosamine and N-acetylglucosamine gave false positive signals when equimolar to glucose. When glucose concentrations in serum were measured, the radiometric glucose assay agreed well with hexokinase/glucose-6-phosphate dehydrogenase (H/GDH)-based and glucose oxidase/H2O2-based glucose assays. The radiometric method for glycogen measurement incorporates previously described isolation and digestion techniques, followed by the radiometric assay of free glucose. When used to measure glycogen in mouse epididymal fat pads, the radiometric glycogen assay correlated well with the H/GDH-based glycogen assay. All three radiometric assays offer several practical advantages over spectral assays.
Bradley, D.C.; Kaslow, H.R. (Univ. of Southern California School of Medicine, Los Angeles (USA))
The ID-KArD technique: In-situ dating on Mars
NASA Astrophysics Data System (ADS)
The ability to measure absolute ages on the Martian surface is crucial for understanding the planet's evolution. A detailed geological history of the Moon has been determined through analysis of returned samples from specific units, and relative ages calculated by crater counting techniques. However, without returned samples or in-situ dating analyses, we lack absolute age markers for Mars and thus cannot accurately or precisely date its well-documented surface. Instead, we have relied on an estimated Mars/Moon cratering ratio and relative crater counting techniques in an attempt to calculate surface ages and classify geological units. The use of such relative parameters diminishes the precision and accuracy for surface age calculations, and thus highlights the need for independent age determinations from returned samples or in-situ dating. In this research, we describe our technique - ID-KArD (Isotope Dilution K-Ar Dating) - intended for in-situ age dating of geological units on the Martian surface. ID-KArD resolves two challenges that have previously obstructed in-situ age dating on Mars: 1) High fusion temperatures are avoided with the use of a lithium-borate flux; 2) Sample mass measurement is not required, due to the addition of an isotope dilution doubly-spiked glass. The glass has a known 39Ar/41K ratio, which removes the need for concentration measurements. Thus, only isotope ratios are required for a K-Ar age determination. ID-KArD has the potential to address Mars chronology inaccuracies, and would be a suitable technique for consideration on future missions. In the first phase of ID-KArD proof of concept, we selected a Viluy trap basalt (K2O ~ 0.7 wt%), with concordant K-Ar and Ar-Ar ages of 354.3 � 3.5 and 357.7 � 1.4 Ma respectively (Courtillot et al., 2010). An aliquot was combined into a crucible with the flux and the spike glass for separate Ar (MAP 215:50, Caltech), followed by K (KEMS, GRC) isotopic analysis. Combining our results, we obtained an age of 351 � 19 Ma (Farley et al., 2013), in good agreement with the previously published ages. For the second phase, we have designed and built a single instrument, capable of analysing both Ar and K from a single sample. The instrument includes two ionisation sources for separate K (thermal) and Ar (electron impact) ionsiation, and a quadrupole mass spectrometer. In addition, we have designed a sample heating mechanism that allows degassing of flux prior to sample addition, and achieves temperatures in the range of the SAM oven on Curiosity. Thus far, the instrument has successfully measured both isotopic systems, and following further testing in the coming weeks, we will date Martian surface analogues, age standards, and finally meteoritic material.
Cartwright, J. A.; Farley, K. A.; Hurowitz, J.; Asimow, P. D.; Jacobson, N. S.
First dating of groundwater with Atom Trap Trace Analysis of 39Ar - technique
NASA Astrophysics Data System (ADS)
The importance of 39Ar as a dating tracer for the time range between 50 and 1000 years has clearly been identified [1]. So far, it has been routinely accessible only by Low-Level-Counting (LLC) in the underground laboratory in Bern requiring a sample size of several tons of water and a measuring time of several weeks [2]. Here we report on the first dating results with 39Ar using an atom optical technique known as Atom Trap Trace Analysis (ATTA). This method has been developed for rare krypton isotopes in the past decade and is now available for routine analysis [3]. However, the applicability of ATTA to 39Ar has only been demonstrated in a proof of principle experiment [4]. We will discuss the essential experimental improvements that were necessary for bringing this method to the level of dating real samples. Our apparatus achieves an atmospheric 39Ar-count-rate of 4.1(3) atoms/h, which corresponds to an 18-fold improvement over the reported results in [4]. Based on that, we dated a groundwater sample of the upper Rhine Graben to 360(68) years within one day of measurement. Further samples of the investigated aquifer system are dated similarly in order to obtain the age information for a comprehensive hydrological study. The apparatus has the potential to measure 39Ar-concentrations on small samples down to less than 1 ccSTP of Argon, corresponding to about 100 ml of air, 2.5 l of water or 1 kg of ice. This opens up the way for a broader application of 39Ar as a tracer e.g. in oceanography or glaciology, where the sample sizes are typically limited to 10 l of water or 1 kg of ice respectively. [1] Loosli, H. H. (1983), A dating method with 39Ar, Earth and Planetary Science Letters, 63, 51-62. [2] P. Collon, W. Kutschera, and Z.-T. Lu. Tracing noble gas radionuclides in the environment. Annual Review of Nuclear and Particle Science, 54(1): 39-67, 2004. [3] W. Jiang et al., An atom counter for measuring 81Kr and 85Kr in environmental samples. Geochimica et Cosmochimica Acta, 91(0):1-6, 2012. [4] Jiang, W. et al. (2011), 39Ar detection at the 10-16 isotopic abundance level with Atom Trap Trace Analysis, Phys. Rev. Lett. 106, DOI: 10.1103/PhysRevLett.106.103001.
Ritterbusch, Florian; Ebser, Sven; Welte, Joachim; Reichel, Thomas; Kersting, Arne; Purtschert, Roland; Aeschbach-Hertig, Werner; Oberthaler, Markus K.
Radiometric instrumentation and measurements guide for photovoltaic performance testing
The Photovoltaic Module and Systems Performance and Engineering Project at the National Renewable Energy Laboratory performs indoor and outdoor standardization, testing, and monitoring of the performance of a wide range of photovoltaic (PV) energy conversion devices and systems. The PV Radiometric Measurements and Evaluation Team (PVSRME) within that project is responsible for measurement and characterization of natural and artificial optical radiation which stimulates the PV effect. The PV manufacturing and research and development community often approaches project members for technical information and guidance. A great area of interest is radiometric instrumentation, measurement techniques, and data analysis applied to understanding and improving PV cell, module, and system performance. At the Photovoltaic Radiometric Measurements Workshop conducted by the PVSRME team in July 1995, the need to communicate knowledge of solar and optical radiometric measurements and instrumentation, gained as a result of NREL`s long-term experiences, was identified as an activity that would promote improved measurement processes and measurement quality in the PV research and manufacturing community. The purpose of this document is to address the practical and engineering need to understand optical and solar radiometric instrument performance, selection, calibration, installation, and maintenance applicable to indoor and outdoor radiometric measurements for PV calibration, performance, and testing applications. An introductory section addresses radiometric concepts and definitions. Next, concepts essential to spectral radiometric measurements are discussed. Broadband radiometric instrumentation and measurement concepts are then discussed. Each type of measurement serves as an important component of the PV cell, module, and system performance measurement and characterization process.
Myers, D.
Application of the 40Ar/39Ar technique to date the Minoan Tuff, Santorini
NASA Astrophysics Data System (ADS)
The age of the catastrophic eruption of the volcano of Santorini during the Bronze Age is well established from 14C dating at 3344.9 � 7.5 a1 (uncertainties quoted as 1-?). Application of the 40Ar/39Ar technique to products from this eruption is used here to (1) investigate the limits of the technique using conventional single collector mass spectrometry on a MAP215-50 instrument, (2) analyse sources of uncertainty to identify major contributing factors for the uncertainty of young 40Ar/39Ar ages, and (3) provide 40Ar/39Ar ages for a sample that has been previously dated via 14C and dendrochronology to further investigate issues with the accuracy of 40Ar/39Ar dating in the late Quaternary. We have separated the plagioclase fraction from the lower Minoan Tuff that immediately overlies the Cape Riva (rp6) tuff in a bay on the west coast of Thira, NW of the town of Oia. Using the calibration of 40Ar/36Ar of Lee et al.2, the decay constant recommended by Min at al.3, and the FCs age of Kuiper et al.4, we calculate an inverse isochron age of 3.7 � 1.6 ka and a trapped 40Ar/36Ar intercept of 299.8 � 1.2, slightly higher than the ratio for atmospheric argon of 298.56 � 0.31, when all steps with ages > 50 ka are included in the regression. Enrichment in radiogenic 40Ar in the steps used for the isochron is extremely low, given the low concentration of K2O in plagioclase and the extremely young age. The stepwise heating approach proved useful because in all 5 replicate experiments unexpectedly high ages showed up at higher step temperatures, suggesting that in each separate some older contaminant was present. The plateaus of each of the replicate experiments had quite reproducible ages, however, and a pooled age was calculated for 23 out of 48 individual steps. The pooled age for the plateau was 17.6 � 4.1 ka, which is high due to the slight component of excess 40Ar in the non-radiogenic component, as revealed from regression analysis. refs: 1SW Manning et al. (2006) Chronology for the Aegean Late Bronze Age 1700-1400 B.C., Science 312, 565 - 569. 2Lee J-Y, et al. (2006), A redetermination of the isotopic abundances of atmospheric Ar. Geochimica et Cosmochimica Acta 70, 4507-4512 3Min K, et al. (2001), Call for an improved set of decay constants for geochronological use. Geochimica et Cosmochimica Acta 65, 111 - 121. 4Kuiper et al. (2008), Synchronizing rock clocks of Earth History. Science 320, 500 - 504.
Wijbrans, J. R.; Kuiper, K.; Morgan, L. E.; Klaver, M.; Vroon, P. Z.
Deep Springs fault, Inyo County, California: An example of the use of relative-dating techniques
This article summarizes faulting in the Deep Springs Valley area, which was studied as part of a systematic evaluation of potentially active faults throughout California by the Division of Mines and Geology. Evaluation of surface fault-rupture hazard is authorized by the Alquist-Priolo Special Studies Zones Act of 1972. This act requires the State Geologist to delineate regulatory zones for faults that are well defined and show that displacement occurred during the last 11,000 years. Fault evaluations for the Division of Mines and Geology Fault Evaluation and Zoning Project are conducted at a detailed reconnaissance level. Evaluations are mainly based on aerial photographic interpretation in which ephemeral fault-produced landforms are identified and mapped. Young alluvial deposits and geomorphic surfaces are identified as either offset or not offset by faults. Field mapping is conducted to verify fault-related geomorphic features and to estimate ages of faulted and unfaulted deposits. The section on scarp degradation and relative dating techniques provides a brief survey of methods used in studies of the Basin and Range province. In these investigations geomorphic evidence is applied to determine the recency of faulting.
Bryant, W.A.
This chapter presents the different methods used or potentially useful to determine the age of an impact event on terrestrial planets or meteorite parent bodies. Two approaches exist: (1) geological methods such as Stratigraphy, which is the study of succeeding geological events, and (2) methods based on natural radioactivity (radiometric dating), as well as the measurement of isotopes produced by
Urs Sch�rer
Small satellite radiometric measurements
A critical need for the Mission to Planet Earth is to provide continuous, well-calibrated radiometric data for the radiation budget. This paper describes a new, compact, flexible radiometer which will provide both spectrally integrated data and data in selected spectral bands. The radiometer design is suitable for use on small satellites, aircraft, or remotely piloted vehicles (RPVs). 12 refs., 2 figs.
Weber, P.G.
Inspection of an end quenched 0.15%-0.2% C, 0.6%-0.9% Mn steel jominy bar with photothermal radiometric techniques
NASA Astrophysics Data System (ADS)
The effect of the cooling rate on hardness and thermal conductivity in a metallurgical Jominy bar made of 0.15%-0.2% C, 0.6%-0.9% Mn (AISI 1018) steel, by means of a water end-quenched heat treatment process without diffusion-controlled case depth, is studied with photothermal radiometry (PTR). It is concluded that our two PTR techniques, common-mode rejection demodulation and conventional 50% duty-cycle square-wave frequency scan, are sensitive to low hardness values and gradients, unlike the high values all previous photothermal studies have dealt with to-date. Both PTR methods have yielded an anticorrelation between thermal conductivity and microhardness in this case as in previous cases with heat-treated and diffusion-controlled case depth profiles. It is shown that the cooling rate strongly affects both hardness and thermal conductivity in the Jominy-bar heat-treating process.
Liu, Yue; Baddour, Natalie; Mandelis, Andreas; Wang, Chinhua
Common Blood Bank Contaminants Evaluated by the Bactec Radiometric System.
National Technical Information Service (NTIS)
Research techniques in blood preservation require frequent entry into blood bags stored at 4 C. Rapid detection of possible contamination and careful evaluation of a selected bacteriological method are essential. Bactec(Registered) radiometric methods (Jo...
B. D. Brown J. D. Kaiser
Stability Considerations for the ERS-1 Wind Scatterometer Radiometric Performance.
National Technical Information Service (NTIS)
Radiometric stability of the ERS-1 wind scatterometer is discussed. Instability sources and compensation techniques are summarized. The temperature and time characteristics of the identified contributors to instability are extremely complex and so a set o...
D. J. Q. Carter
Radiometric Methods for Rapid Diagnosis of Viral Infection.
National Technical Information Service (NTIS)
Three radiometric techniques were investigated for monitoring the effects of herpes simplex virus type I and II and cytomegalovirus on the metabolism of human embryonic lung fibroblast (WI-38) monolayers. The study was based on the hypothesis that (1) ear...
H. N. Wagner M. F. Tsan
NASA Astrophysics Data System (ADS)
We present analysis of radiometric calibration data for MOSES, the Multi-Order Solar EUV Spectrograph. MOSES is an EUV imaging spectrograph which uses a spherical grating to feed three rear illuminated CCDs, one for each of the m = 0 and m = �1 spectral orders of the grating. MOSES was calibrated end-to-end at the EUV radiometric calibration facility at Rutherford Appleton Laboratory, using a well characterized hollow cathode source traceable to the BESSY synchrotron. We analyze these data and present the end-to-end instrument response (DN per incident photon) for each of MOSES three CCD channels. This work was supported in part by a grant from the NASA Solar and Heliospheric Physics LCAS program.
Rust, Thomas; Fox, J. L.; Kankelborg, C. C.; Thomas, R. J.
Determination of recent sedimentation rates and pattern in Lake Naini, India by 210Pb and 137Cs dating techniques
Environmental 210Pb (natural) and 137Cs (anthropogenic) dating techniques were applied to determine recent sedimentation rates and pattern in Lake Naini, Uttar Pradesh, India. Core samples from different locations in the lake were collected and analysed for 210Pb and 137Cs. From the analysis it appears that the lake is not reducing in depth at a rate reported by earlier investigations. Recent
U. Saravana Kumar; S. V. Navada; S. M. Rao; Rm. P. Nachiappan; Bhishm Kumar; T. M. Krishnamoorthy; S. K. Jha; V. K. Shukla
Radiometric cloud imaging with an uncooled microbolometer thermal infrared camera.
An uncooled microbolometer-array thermal infrared camera has been incorporated into a remote sensing system for radiometric sky imaging. The radiometric calibration is validated and improved through direct comparison with spectrally integrated data from the Atmospheric Emitted Radiance Interferometer (AERI). With the improved calibration, the Infrared Cloud Imager (ICI) system routinely obtains sky images with radiometric uncertainty less than 0.5 W/(m(2 )sr) for extended deployments in challenging field environments. We demonstrate the infrared cloud imaging technique with still and time-lapse imagery of clear and cloudy skies, including stratus, cirrus, and wave clouds. PMID:19498585
Shaw, Joseph; Nugent, Paul; Pust, Nathan; Thurairajah, Brentha; Mizutani, Kohei
Identifying and Dating Metamorphic Zircons in Clastic Rocks and River Sediments and the Technique of U-Pb Dating Fine Overgrowths
NASA Astrophysics Data System (ADS)
Unique identification of metamorphic zircon in river sands and clastic rocks using any of composition, morphology or internal structure is difficult but in two situations we can confidently identify zircon associated with metamorphism: discrete overgrowths on older cores, and wide zones of Pb loss (diffusion). The former may be associated with partial melting but marks the age and culmination of metamorphism. Routine U-Th-Pb dating and analysis of low abundance trace elements of thin zircon overgrowths was unavailable until our laser rim-piercing technique was developed at ANU where we have an Excimer laser (193 nm wavelength; long focal length) attached to an Agilent 7500S Q-ICP-MS. We fasten HCl-washed but otherwise unprepared zircons onto adhesive tape and in a sample chamber carrying He+Ar we ablate 32 micron wide holes about 25 micron deep into the zircon. The ablated material is carried into the ICP. The impact of the technique is clear from an example of the Ganges River sand. If mounted in the traditional way with zircons embedded in epoxy and polished to expose cores, and using a shallow spot U-Pb dating method, knowledge of the significant adjacent Himalayan orogeny could only ensue if dozens to hundreds of analyses were undertaken and discordia were constructed from many grains. Discordia must be fit to those grains with the same inherited age, a challenge for a river sand sample. Using the rim-piercing technique gives us indication of the Himalayan event in about 5 to 10 percent of all analysed grains. In 60 seconds, a metamorphic rim, Pb loss region, and inherited core can be analysed. If the rim is wider than 5 microns a precise age can be measured. Moreover, even if the rim is not preserved, and the core not encountered, the Pb loss zone if wide enough (~15 mcirons) can be used to construct a discordia on that single grain with moderately precise lower and upper intercept ages. In several zircons from sediments drained from high-grade metamorphic terranes, we have encountered zones where 206Pb/238U changes continuously over 25 microns while the 207Pb/206Pb remains constant. This result strongly suggests Pb diffusion over broad areas in high-grade metamorphic zircons that do not appear metamict.
Allen, C. M.; Campbell, I. H.
Radiometric Dating and Quantitative Analysis of Elements in Depth Profiles of Sediments by Means of Nuclear Physical as Well as X-Ray Fluorescence and Atomic Emission Spectroscopic Methods.
National Technical Information Service (NTIS)
The measurement of heavy metal concentration in sediments is of great importance for the assessment of water quality. If dating of the different layers of sediment cores is possible, informations about the history of pollution can be inferred. This paper ...
M. Schoenburg
Radiometric Compensation through Inverse Light Transport
Radiometric compensation techniques allow seam- less projections onto complex everyday surfaces. Im- plemented with projector-camera systems they support the presentation of visual content in situations where projection-optimized screens are not available or not desired - as in museums, historic sites, air-plane cabins, or stage performances. We propose a novel approach that employs the full light transport between a projector and
Gordon Wetzstein; Oliver Bimber
Advances in U-Th-Pb-He Double Dating Techniques and Applications in Diamond Exploration
NASA Astrophysics Data System (ADS)
Zircon entrained within kimberlite deposits should have distinctive U-Th-Pb-He signatures compared to those found in the host terrane. To investigate the application of zircon double dating to kimberlite diamond exploration, we performed (U-Th)/He and SHRIMP U/Pb double dating analysis of zircon from the Sacramore kimberlite pipe located in the Merlin field in the Northern Territory of Australia and of detrital zircon from a regional sample of the kimberlitic host, the Bukalara Sandstone. The Sacramore zircon U/Pb age (n=14) ranged from 1541-2433 Ma, consistent with the Mesoproterozoic formation of the North Australian Craton and indicating that the kimberlitic zircon is of xenocrystic origin. (U- Th)/He thermochronometry of these kimberlite zircon xenocrysts (n=33) yielded a mean weighted average age of 368�4 Ma (2?), concordant with a previously determined phlogopite Rb-Sr age of 367�4 Ma for the Merlin field. The U/Pb age (1472-2939 Ma; n=41) of detrital zircon from the Bukalara Sandstone is statistically indistinguishable from that of the kimberlite zircon xenocrysts, while the detrital (U-Th)/He ages range from 459 to 1279 Ma. A bivariate age density distribution approach (Sircombe 2006, Geochem Geophys Geosyst V7) using the open-licence R statistical package allows 3D visualization of double-dated zircon populations. The consistently young (U-Th)/He ages of the kimberlite zircon xenocrysts distinguish them from surficial detrital zircon. This geochemical feature could have application for regional diamond exploration in tropical and sub-tropical climates where standard kimberlite indicator minerals (e.g., Cr-pyrope, Cr-diopside, picroilmenite, chromite) are prone to destruction by chemical weathering. Up to 40% of detrital zircon grains obtained from streams draining the Merlin kimberlite field have (U-Th)/He ages comparable to those obtained from the Sacramore pipe.
McInnes, B. I.; Evans, N. J.; McDonald, B. J.; Chia, J.
An integrated framework for interpolating airborne geophysical data with special reference to radiometrics
New processing techniques for airborne radiometric data make use of the information contained in all 256 channels of a radiometric spectrum, improving the final quality obtained. However, visualisation and interpretation of the processed data require interpolation to a regular grid and current methods for doing this are generally unsatisfactory. We highlight alternative interpolation techniques (kriging, radial basis functions, tension splines,
Stephen Billings; Desmond J. FitzGerald
Radiation-induced signals of gypsum crystals analysed by ESR and TL techniques applied to dating
NASA Astrophysics Data System (ADS)
Natural crystals of terrestrial gypsum were investigated concerning the radiation effects on Electron spin resonance (ESR) and Thermoluminescence (TL) properties and their application for geological dating. ESR signals of Fe 3+, Mn 2+, G1 ( SO3-, g = 2.003) and G2 ( SO4-, g?=2.018g?=2.009) centers were observed. The thermal stability and dose response of the ESR signals were found to be suitable for an age determination using a signal at g = 2.009. The intensity of this center increased with ?-radiation and the additive dose method for this ESR center yielded accumulated dose GD of 67.4 � 10.1 Gy. Using U, Th and K contents plus the cosmic-ray contribution, a dose rate of 1.92 � 0.22 mGy/year has been obtained. We have determined the ESR age of the gypsums to be (35 � 4) � 10 3 years. TL peaks at 157 and 278 �C were observed. By using initial rise method the thermal activation energy of 278 �C TL peak was found to be underestimated, probably due to the thermal quenching. Activation energies and frequency factors obtained by the method of varying the heating rate indicate lifetime of 4.09 � 10 7 years (at 15 �C) for 278 �C peak. The additive dose method applied to this TL peak yielded GD of 75 � 11 Gy. The corresponding TL age using the 278 �C TL peak was found to be (39 � 5) � 10 3 years for gypsum sample. The TL age of this sample is consistent with the ESR age within experimental error limits. The obtained ESR and TL ages are not consistent with the expectations of geologists. This contradiction is probably due to the repeatedly recrystallisation of gypsum samples under the environmental conditions after their formation in the upper Miocene-Pliocene Epoch.
Ayda?, Canan; Engin, Birol; Ayd?n, Talat
Dating of the Urengoi tectites by the track technique using an age standard
NASA Astrophysics Data System (ADS)
The age of three Urengoi (northwestern Siberia) tektites was estimated by the 'repeated-polishing' version of the track technique, using the Apatite FC-3 as the age standard. The average age for the three samples was found to be 23 + or - 1.6 million years. This age does not coincide with the age of known tektite fields on the earth, and it is not close to the age of the certain impact craters on Soviet territory. It is concluded that the Urengoi tektites may have originated on a hitherto unknown tektite dispersion field.
Komarov, A. N.; Masaitis, V. L.; Ezerskii, V. A.
Correction function in the Lidar equation and the solution techniques for CO2 Lidar date reduction
NASA Technical Reports Server (NTRS)
For lidar systems with long laser pulses the unusual behavior of the near-range signals causes serious difficulties and large errors in reduction. The commonly used lidar equation is no longer applicable since the convolution of the laser pulse with the atmospheric parameter distributions should be taken into account. It is important to give more insight into this problem and find the solution techniques. Starting from the original equation, a general form is suggested for the single scattering lidar equation where a correction function Cr is introduced. The correction Function Cr(R) derived from the original equation indicates the departure from the normal lidar equation. Examples of Cr(R) for a coaxial CO2 lidar system are presented. The Differential Absorption Lidar (DIAL) errors caused by the differences of Cr(R) for H2O measurements are plotted against height.
Zhao, Y.; Lea, T. K.; Schotland, R. M.
Limulus Test for Pyrogens and Radiometric Sterility Tests on Radiopharmaceuticals. Part of a Coordinated Programme. Final Report for the Period 1 September 1972--30 April 1976.
National Technical Information Service (NTIS)
Sterility testing of radiopharmaceuticals prepared at BARC were carried out using the radiometric technique (Radiometric detection of the metabolic product exp 14 Co sub 2 ). Batches of different radiopharmaceuticals were tested for pyrogen using the limu...
N. G. S. Gopal
Aliased Noise in Radiometric Measurements.
National Technical Information Service (NTIS)
The magnitude of aliased noise that degrades the accuracy of continuous reconstructions of discrete radiometric measurements was evaluated as a function of the spatial response and sampling intervals of the radiometer, and of the resolution of the reconst...
F. O. Huck S. K. Park N. Halyo S. T. Stallman
A potential dating technique using 228Th\\/ 228Ra ratio for tracing the chronosequence of elemental concentrations in plants
We propose a radiometric method based on measurement of the radioactivity of the naturally occurring radionuclides 228Ra and 228Th and the derived 228Th\\/228Ra ratios in plant samples to estimate plant age and the corresponding nutritional conditions in a field-growing fern, Dicranopteris linearis. Plant age (tissue age) was associated with the 228Th\\/228Ra ratio in fronds, which implies the accumulation time of
J. H. Chao; H. Niu; C. Y. Chiu; C. Lin
Comparing OSL and CN techniques for dating fluvial terraces and estimating surface process rates in Pamir
NASA Astrophysics Data System (ADS)
The quantification of surface process rates is crucial for understanding the topographic evolution of high mountains. Spatial and temporal variations in fluvial incision and basin-wide erosion enable to decipher the role of tectonic and climatic drivers. The Pamir is peculiar in both aspects because of its location at the western end of the India-Asia collision zone, and its position at the edge of two atmospheric circulation systems, the Westerlies and the Indian Summer Monsoon. The architecture of the Panj river network indicates prominent variations across the main tectonic structures of the Pamir. The trunk stream, deflects from the predominantly westward river orientation and cuts across the southern and central Pamir domes before doubling back to the west and leaving the orogen. Optically stimulated luminescence (OSL) dating of fluvial terraces reveals short-term sedimentation along the trunk stream during the last ~25 kyr. The agreement of OSL results to new exposure ages based on the cosmogenic nuclide (CN) 10Be confirms accurate terrace age modelling and treatment of incomplete bleaching. The consistent terrace sedimentation and exposure ages suggest also fast terrace abandonment and rapid onset of incision. Considerable differences in terrace heights reflect high spatial variations of fluvial incision, independent of time interval, change in rock type or catchment increase. Highest rates of (5.9 � 1.1) mm/yr to (10.0 � 2.0) mm/yr describe the fluvial dynamic across the Shakhdara Dome and that related to the Darvaz Fault Zone. Lower rates of (3.9 � 0.6) mm/yr to (4.5 � 0.7) mm/yr indicate a transient stage north of the Yazgulom Dome. Fluvial incision decreases to rates ranging from (1.7 � 0.3) mm/yr to (3.9 � 0.7) mm/yr in graded river reaches associated to southern dome boundaries. The pattern agrees to the interpretation of successive upstream river captures across the southern and central Pamir domes inferred from morphometric analyses of river and valley profiles. Basin-wide erosion rates based on 10Be concentrations in modern fluvial sediments yield relatively consistent rates between (0.61 � 0.1) mm/yr and (0.75 � 0.14) mm/yr along the Panj. The increasing Panj catchment averages variations of tributary basins, but minor variations in erosion rates of along-stream sub-basins resemble the pattern of OSL-based incision rates. In contrast, basin-wide erosion rates of tributary basins clearly differentiate between plateau-related sub-basins of (0.05 � 0.01) mm/yr to (0.17 � 0.03) mm/yr, and plateau margin-related sub-basins of (0.38 � 0.06) mm/yr to (1.43 � 0.26) mm/yr. The differentiation in plateau-related and marginal sub-basins and the northward increase in erosion rates correlate with the 75-percentile of the slope distribution within respective basins and to a minor degree to cumulative annual precipitation.
Fuchs, Margret; Gloaguen, Richard; Pohl, Eric; Sulaymonova, Vasila; Merchel, Silke; Rugel, Georg
Absolute dating of Middle Pleistocene palaeontological records from the Guadix-Baza basin, Spain, using extended-range OSL dating techniques
NASA Astrophysics Data System (ADS)
The Guadix-Baza basin, southern Spain, contains an important archive of palustrine/lacustrine records covering the late Miocene to Middle Pleistocene. Numerous palaentological sites have been described within the Guadix-Baza basin, which record faunal and climatic changes spanning the Early to Middle Pleistocene, and contain some of the earliest evidence of human presence in Europe. Chronological control for these palustrine/lacustrine sequences has been achieved via a combination of relative dating methods, such as stratigraphic correlations, palaeomagnatism and biochronology. However, in spite of the large number of research undertaken over the past 20 years, absolute chronological control is still lacking for these sites due to (i) the antiquity of the deposits, which precludes the use of radiocarbon and conventional optically stimulated luminescence (OSL) dating, and (ii) the lack of datable material for long-ranging methods, such as Ar/Ar on tephras or U-series. Conventional OSL dating of quartz is now routinely applied to sedimentary deposits that are less than 200 ka old, but it is not generally suitable for older deposits owing to saturation of the OSL signal. Over the past 10 years, a series of extended range OSL methodologies have been proposed for dating Middle Pleistocene deposits, which make use of luminescence signals with higher saturation limits. Here we report on chronologies obtained using so-called thermally-transferred (TT) OSL dating and post-IR IRSL feldspar dating of Middle Pleistocene deposits from the Baza sub-basin. In total, 5 samples were collected from deposits bracketing the main palaeontological/archaeological horizons at two sites (Huescar-1 and Cullar de Baza-1). Single-grain OSL was also applied to the youngest samples to obtain additional chronologies for comparison with the multi-grain TT-OSL and post-IR IRSL ages. The suitability of the TT-OSL and post-IR IRSL signals for dating these deposits is tested via a series of quality assurance criteria (signal composition, dose recovery tests, bleaching tests, sensitivity correction assessments). The resultant extended-age OSL chronologies are presented and used to assess (i) the accuracy of existing chronostratigraphic frameworks developed at these sites, and (ii) the wider applicability of these novel dating approaches for constraining early human presence in Europe.
Demuro, Martina; Arnold, Lee; Pares, Josep
Precision and accuracy of two luminescence dating techniques for retrospective dosimetry: SAR-OSL and SAR-ITL
NASA Astrophysics Data System (ADS)
Luminescence techniques based on thermally or optically stimulated signals are used extensively for estimating the equivalent dose (ED) of quartz samples for dating and retrospective dosimetry. This paper presents simulations of two luminescence dating protocols which use single aliquots of the quartz samples. The first protocol is the well-known single-aliquot regenerative optically stimulated luminescence (SAR-OSL) protocol for quartz. The second protocol was developed more recently and is based on a thermoluminescence (TL) signal measured under isothermal conditions (termed the SAR-ITL technique). The simulations are carried out using a recently published comprehensive kinetic model for quartz, consisting of 11 electron and hole traps and centers. The complete sequence of the two experimental protocols is simulated using the same set of kinetic parameters. The simulated dose response curves for the two protocols are found to be very similar to published experimental data. The relative intrinsic accuracy and precision of the two techniques is estimated by simulating one hundred random variants of the natural samples, and by calculating the equivalent doses using each technique. The 100 simulated natural variants are generated by keeping the transition probabilities between energy levels fixed, while allowing simultaneous random variations of the concentrations of the 11 energy levels. The SAR-OSL protocol was found to be intrinsically both more accurate and more precise than the SAR-ITL protocol. We investigate several experimental factors which affect the precision and accuracy of the two protocols. New simulations are presented for commonly used sensitivity tests consisting of successive cycles of sample irradiation with the same dose, followed by measurements of the sensitivity corrected L/ T signals. These new simulations provide valuable insight into the previously reported sensitivity changes taking place during application of the SAR-ITL protocol.
Pagonis, Vasilis; Baker, Atlee; Larsen, Meredith; Thompson, Zachary
Chemical Principles Revisited: Archaeological Dating.
ERIC Educational Resources Information Center
Discusses methods used to date archaeological artifacts and other remains. They include: (1) nuclear dating techniques (radiocarbon dating, accelerator radiocarbon dating, thermoluminescence, and others); (2) chemical dating techniques (amino acid racemization, obsidian hydration dating, elemental content changes, and thermal analysis dating); and�
Rowe, M. W.
Radiometric correction of SAR images of varying terrain heights
NASA Technical Reports Server (NTRS)
The advantages and disadvantages of three different approaches to solving the problem of the radiometric correction of synthetic aperture radar (SAR) images of varying terrain heights are presented. The first approach involves registration of a digital elevation model (DEM) of the terrain to the image, determination of the local elevation and incidence angles, and appropriate radiometric correction. The second approach uses a DEM generated from interferometric SAR data to derive the elevation and incidence angle maps. In the third approach, a monopulse technique is employed to determine the elevation angle only. The relative errors in radiometric correction between these approaches are assessed. Calibration errors are estimated using corner reflectors deployed within some of the scenes imaged by the Jet Propulsion Laboratory airborne SAR (JPL AIRSAR).
Freeman, A.; Moghaddam, M.; Zink, M.; Zebker, H.
Radiometric Methods for Rapid Diagnosis of Viral Infection.
National Technical Information Service (NTIS)
A rapid radiometric technique was developed for detecting the presence of herpes simplex virus type 1 in stationary monolayers of the diploid cell line WI-38. The time of detection was compared to that obtained from visual examinations for cytopathic effe...
S. M. Larson P. Charache H. N. Wagner
Geochemistry and radiometric dating of a Middle Pleistocene peat
Uranium, lead, and sulphur data for a Middle Pleistocene interglacial peat deposit from Norfolk, UK, suggest that uptake of these elements was synchronous and confined to a single early diagenetic episode, probably coeval with peat formation. Sulphur isotope data indicate that reducing conditions have been maintained within the deposit throughout its history. Both uranium and lead concentration profiles show a marked discontinuity near the middle of the bed, probably indicating an environmental change, possibly emergence. The lead isotope data are compatible with a single lead component below the discontinuity and two components above. Groundwater is thought to be the dominant source of lead with an additional airfall component present in the upper peat. The uranium and lead concentration profiles below the discontinuity and the sulfur isotope profile throughout the peat support the view that these elements were sequestered from upwelling groundwaters. 35 refs., 9 figs., 3 tabs.
Rowe, P.J.; Atkinson, T.C. [Univ. of East Anglia, Norwich (United Kingdom)] [Univ. of East Anglia, Norwich (United Kingdom); Richards, D.A.; Bottrell, S.H.; Cliff, R.A. [Univ. of Leeds (United Kingdom)] [and others] [Univ. of Leeds (United Kingdom); and others
Radiometric Dating of the Ubeidiya Formation, Jordan Valley, Israel
THE Ubeidiya Formation1 is known from three localities (Fig. 1) within the Jordan Valley, where it is steeply tilted, faulted and folded2,3. It is rich in prehistoric remains, representing the Developed Oldowan and Early Acheulean4. The Ubeidiya Formation is important in the Pleistocene history of the Jordan Valley for two reasons: it is the youngest sedimentary sequence to be severely
A. Horowitz; G. SIEDNER; O. BAR YOSEF
Geochemistry and radiometric dating of a Middle Pleistocene peat
Uranium, lead, and sulphur data for a Middle Pleistocene interglacial peat deposit from Norfolk, UK, suggest that uptake of these elements was synchronous and confined to a single early diagenetic episode, probably coeval with peat formation. Sulphur isotope data indicate that reducing conditions have been maintained within the deposit throughout its history. Both uranium and lead concentration profiles show a
Peter J. Rowe; David A. Richards; Timothy C. Atkinson; Simon H. Bottrell; Robert A. Cliff
Aliased noise in radiometric measurements
NASA Technical Reports Server (NTRS)
The magnitude of aliased noise that degrades the accuracy of continuous reconstructions of discrete radiometric measurements was evaluated as a function of the spatial response and sampling intervals of the radiometer, and of the resolution of the reconstructed measurements. A Wiener spectrum, representative of a wide range of scenes, was used to characterize the radiance fluctuations.
Huck, F. O.; Park, S. K.; Halyo, N.; Stallman, S. T.
Dating loess with high temperature IRSL signals from polymineral fine grains: luminescence characteristics and comparison with conventional techniques
NASA Astrophysics Data System (ADS)
It is well known that loess deposits contain detailed terrestrial archives of palaeoenvironmental changes. Unfortunately, loess sequences often lack a reliable absolute chronology, and thus these changes are difficult to constrain in time. Luminescence dating is the technique of choice to address this issue. Quartz and feldspar are the most commonly used dosimeters in luminescence dating. The age range of standard quartz OSL is usually limited by the saturation level of ~200 Gy (corresponding to ~50 ka). In contrast, the age range of feldspar IRSL signals - which usually have a more extended growth curve (up to ~2000 Gy) - is hampered by anomalous fading for which a reliable correction is still not available. Recently, Thomsen et al. (2008) identified several laboratory-induced feldspar signals which show less anomalous fading than the standard IRSL signal stimulated at 50�C. Based on this work, Buylaert et al. (accepted) tested a post-IR IR signal, i.e. IR bleach at 50�C and subsequent IRSL measurement at 225�C, and observed significantly lower fading rates in nature for a number of coarse-grained K-feldspar samples. In this study we explore the possibility of using such a post-IR IR signal from polymineral fine grains extracted from loess. Murray et al. (accepted) showed that a more stringent preheat treatment (320�C for 60 s) can be safely used for feldspar; as a result, we have been able to use a post-IR IR measurement temperature of 290�C, higher than that in the study of Buylaert et al. (accepted), with the expectation that this might further reduce the observed fading rate. The results of the elevated temperature IRSL signal fading measurements clearly indicate a significantly lower fading rate (g2days values typically 1-1.5 %/decade) than the standard IRSL measured at 50�C (g2days values typically 3 %/decade). Results of the performance in the SAR protocol (recycling ratios, recuperation and dose recovery) are very encouraging (measured dose within 15% of the given dose). This high temperature signal is also bleachable by daylight, as confirmed by the values of De observed in young samples and by performing controlled laboratory bleaching experiments. The enhanced post-IR IR dating protocol was applied to loess samples from Austria and Japan and compared with standard IRSL at 50�C and quartz OSL measurements. First results suggest that there is good agreement for the younger samples of Weichselian age but that the ages begin to deviate for the older samples. Final results, including a comparison with independent age control provided by known age tephra layers for the Japan samples (Watanuki et al., 2005), will be presented. Buylaert, J. P., Murray, A. S., Thomsen, K. J., Jain, M., accepted. Testing the potential of an elevated temperature IRSL signal from K-feldspar. Radiation Measurements, Special Issue, LED08. Murray, A. S., Buylaert, J. P., Thomsen, K. J., Jain, M., accepted. The Effect of Preheating on the IRSL Signal from Feldspar. Radiation Measurements, Special Issue, LED08. Thomsen, K. J., Murray, A. S., Jain, M., B�tter-Jensen, L., 2008. Laboratory fading rates of various luminescence signals from feldspar-rich sediment extracts. Radiation Measurements, 43, 1474-1486. Watanuki, T., Murray, A. S., Tsukamoto, S., 2005. Quartz and polymineral luminescence dating of Japanese loess over the last 0.6 Ma: Comparison with an independent chronology. Earth and Planetary Science Letters, 240, 774-789.
Thiel, C.; Buylaert, J.-P.; Murray, A. S.; Tsukamoto, S.; Jain, M.; Frechen, M.
Real-time adaptive radiometric compensation.
Recent radiometric compensation techniques make it possible to project images onto colored and textured surfaces. This is realized with projector-camera systems by scanning the projection surface on a per-pixel basis. Using the captured information, a compensation image is calculated that neutralizes geometric distortions and color blending caused by the underlying surface. As a result, the brightness and the contrast of the input image is reduced compared to a conventional projection onto a white canvas. If the input image is not manipulated in its intensities, the compensation image can contain values that are outside the dynamic range of the projector. These will lead to clipping errors and to visible artifacts on the surface. In this article, we present an innovative algorithm that dynamically adjusts the content of the input images before radiometric compensation is carried out. This reduces the perceived visual artifacts while simultaneously preserving a maximum of luminance and contrast. The algorithm is implemented entirely on the GPU and is the first of its kind to run in real-time. PMID:17993705
Grundh�fer, Anselm; Bimber, Oliver
JACIE Radiometric Assessment of QuickBird Multispectral Imagery
NASA Technical Reports Server (NTRS)
Radiometric calibration of commercial imaging satellite products is required to ensure that science and application communities can place confidence in the imagery they use and can fully understand its properties. Inaccurate radiometric calibrations can lead to erroneous decisions and invalid conclusions and can limit intercomparisons with other systems. To address this calibration need, the NASA Stennis Space Center (SSC) Earth Science Applications (ESA) directorate,through the Joint Agency for Commercial Imagery Evaluation (JACIE) framework, established a commercial imaging satellite radiometric calibration team consisting of two groups: 1) NASA SSC ESA, supported by South Dakota State University, and 2) the University of Arizona Remote Sensing Group. The two groups determined the absolute radiometric calibration coefficients of the Digital Globe 4-band, 2.4-m QuickBird multispectral product covering the visible through near-infrared spectral region. For a 2-year period beginning in 2002, both groups employed some variant of a reflectance-based vicarious calibration approach, which required ground-based measurements coincident with QuickBird image acquisitions and radiative transfer calculations. The groups chose several study sites throughout the United States that covered nearly the entire dynamic range of the QuickBird sensor. QuickBird at-sensor radiance values were compared with those estimated by the two independent groups to determine the QuickBird sensor's radiometric accuracy. Approximately 20 at-sensor radiance estimates were vicariously determined each year. The estimates were combined to provide a high-precision radiometric gain calibration coefficient. The results of this evaluation provide the user community with an independent assessment of the QuickBird sensor's absolute calibration and stability over the 2-year period. While the techniques and method described reflect those developed at the NASA SSC, the results of both JACIE team groups are included in this paper.
Pagnutti, Mary; Carver, David; Holekamp, Kara; Knowlton, Kelly; Ryan, Robert; Zanoni, Vicki; Thome, Kurtis; Aaron, David
Influence of Lossy Compressed DEM on Radiometric Correction for Land Cover Classification of Remote Sensing Images
NASA Astrophysics Data System (ADS)
World coverage Digital Elevation Models (DEM) have progressively increased their spatial resolution (e.g., ETOPO, SRTM, or Aster GDEM) and, consequently, their storage requirements. On the other hand, lossy data compression facilitates accessing, sharing and transmitting large spatial datasets in environments with limited storage. However, since lossy compression modifies the original information, rigorous studies are needed to understand its effects and consequences. The present work analyzes the influence of DEM quality -modified by lossy compression-, on the radiometric correction of remote sensing imagery, and the eventual propagation of the uncertainty in the resulting land cover classification. Radiometric correction is usually composed of two parts: atmospheric correction and topographical correction. For topographical correction, DEM provides the altimetry information that allows modeling the incidence radiation on terrain surface (cast shadows, self shadows, etc). To quantify the effects of the DEM lossy compression on the radiometric correction, we use radiometrically corrected images for classification purposes, and compare the accuracy of two standard coding techniques for a wide range of compression ratios. The DEM has been obtained by resampling the DEM v.2 of Catalonia (ICC), originally having 15 m resolution, to the Landsat TM resolution. The Aster DEM has been used to fill the gaps beyond the administrative limits of Catalonia. The DEM has been lossy compressed with two coding standards at compression ratios 5:1, 10:1, 20:1, 100:1 and 200:1. The employed coding standards have been JPEG2000 and CCSDS-IDC; the former is an international ISO/ITU-T standard for almost any type of images, while the latter is a recommendation of the CCSDS consortium for mono-component remote sensing images. Both techniques are wavelet-based followed by an entropy-coding stage. Also, for large compression ratios, both techniques need a post processing for correctly delimiting coastline, avoiding the confusion between elevation and no-data values. Six (from March 2005 to May 2007) geometrically corrected Landsat-5 images on the path-row 197-031 have been used. The six optical bands and the NDVI for each date have been introduced in a powerful hybrid classification process. The training areas and the ground truth have been obtained from the Mapa de Cobertes del S�l de Catalunya (v. 3), a land cover map created by photointerpretation of 0.5 m orthophotomaps acquired between 2005 and 2007 and covering all the extension of Catalonia. The legend has been reduced from 233 categories to 21. Preliminary results have shown that the effect on land cover classification of applying lossy compression to the DEM used in the radiometric correction is small (lower than 1%) even for compression ratios up to 200:1. Comparing classification performance after a compression of 5:1 and and a compression of 200:1 with both coding standards showed that: a) the percentage of correctly classified image was 73%; b) 20% was wrongly classified; c) 3.5% was wrongly classified at compression ratio 5:1; and d) also 3.5% was wrongly classified at compression ratio 200:1. These results are the first in the literature to analyze the effect of DEM lossy compressing when DEM are employed for radiometric correction.
Mor�, G.; Pesquer, L.; Blanes, I.; Serra-Sagrist�, J.; Pons, X.
PALSAR Radiometric and Geometric Calibration
This paper summarizes the results obtained from geometric and radiometric calibrations of the Phased-Array L-Band Synthetic Aperture Radar (PALSAR) on the Advanced Land Observing Satellite, which has been in space for three years. All of the imaging modes of the PALSAR, i.e., single, dual, and full polarimetric strip modes and scanning synthetic aperture radar (SCANSAR), were calibrated and validated using
Masanobu Shimada; Osamu Isoguchi; Takeo Tadono; Kazuo Isono
NSDL National Science Digital Library
In this exercise, students investigate methods used by geologists studying active tectonics for determining ages in actual numbers of years. Introductory materials describe the three most-used techniques for dating material formed during the Quaternary Period (approximately the last 1.65 million years), discuss the concepts of radioactive decay and half-life, and explain how these may be used to determine the numerical age of an object or substance. The exercise includes a set of problems in which students calculate isotopic abundance, half-life, decay rate, and absolute age. Example problems and a bibliography are provided.
Pinter, Nicholas
Helium-4 characteristics of groundwaters from Central Australia: Comparative chronology with chlorine-36 and carbon-14 dating techniques
NASA Astrophysics Data System (ADS)
SummaryHelium isotope and concentration characteristics were determined for a suite of groundwater samples from the Amadeus Basin in Central Australia. Two study areas include a wellfield south of Alice Springs, and the Dune Plains and Mututjulu aquifers near Uluru. Measurements of 36Cl/Cl and 14C on the same sample suite enable us to assess the relative applicability of the three groundwater chronometers over a range of anticipated groundwater residence times (ages), and to investigate possible causes of discordant 'ages' derived from the different groundwater dating techniques. Results from the analyses of 39 groundwater samples reveal helium-4 ( 4He) concentrations that range from 0.80 to 98.8 (�10 -7 cm 3 STP g -1 H 2O) in the Alice Springs samples, and from 0.47 to 65.6 (�10 -7 cm 3 STP g -1 H 2O) in the Uluru samples. 4He concentrations yield uncorrected groundwater residence times (i.e. time since recharge) of between modern to >2500 ka (near Alice Springs) and modern to 1600 ka (near Uluru) assuming an effective porosity of 20%, and uranium and thorium contents of 1.7 and 6.1 ppm, respectively. 36Cl/Cl ratios on the same samples range from 93 to 158 (�10 -15) (near Alice Springs) and from 80 to 335 (�10 -15) (near Uluru) representing groundwater residence times near Alice Springs from modern to >200 ka, and from modern to >300 ka near Uluru. Percent modern carbon (pmc) on the same samples ranged from 64.9 to 12.5 pmc near Alice Springs, and from 93.5 to <2 pmc near Uluru. Corresponding 14C residence times for the Alice Springs samples range from modern to 13.0 ka, and near Uluru from modern to >30 ka. For the Amadeus Basin groundwater samples, the 4He method (uncorrected) over-estimates groundwater residence time compared to 36Cl and 14C techniques. This implies the presence of an extraneous He component or basal flux of He ( J0). To reconcile groundwater 4He and 14C residence times, it is necessary to adopt J0 values between 0 and 30 (�10 -8) cm 3 STP He cm -2 a -1 which supplements in situ produced He within the aquifer. Adoption of J0 values over this range lowers 4He residence times relative to 36Cl and produces closer agreement between the 4He and 14C chronometers. The extraneous He component (basal flux) in Amadeus Basin samples is dominated by radiogenic crustal 4He without a detectable amount of mantle-derived 3He. We conclude that the stable tectonic regime, albeit with the presence of major faults within the basin, inhibits the input of mantle volatiles to the groundwater system so that in this region, diffusion is the dominant transport mechanism for He in the crust.
Kulongoski, Justin T.; Hilton, David R.; Cresswell, Richard G.; Hostetler, Stephen; Jacobson, Gerry
The Radiometric Map of Australia
NASA Astrophysics Data System (ADS)
Geoscience Australia and the Australian State and Territory Geological Surveys have systematically surveyed most of the Australian continent over the past 40 years using airborne gamma-ray spectrometry to map potassium, uranium and thorium elemental concentrations at the Earth's surface. However, the individual surveys that comprise the national gamma-ray spectrometric radioelement database are not all registered to the same datum. This limits the usefulness of the database as it is not possible to easily combine surveys into regional compilations or make accurate comparisons between radiometric signatures in different survey areas. To solve these problems, Geoscience Australia has undertaken an Australia-Wide Airborne Geophysical Survey (AWAGS), funded under the Australian Government's Onshore Energy Security Program, to serve as a radioelement baseline for all current and future airborne gamma-ray spectrometric surveys in Australia. The AWAGS survey has been back-calibrated to the International Atomic Energy Agency's (IAEA) radioelement datum. We have used the AWAGS data to level the national radioelement database by estimating survey correction factors that, once applied, minimise both the differences in radioelement estimates between surveys (where these surveys overlap) and the differences between the surveys and the AWAGS traverses. The database is thus effectively levelled to the IAEA datum. The levelled database has been used to produce the first `Radiometric Map of Australia' - levelled and merged composite potassium (% K), uranium (ppm eU) and thorium (ppm eTh) grids over Australia at 100m resolution. Interpreters can use the map to reliably compare the radiometric signatures observed over different parts of Australia. This enables the assessment of key mineralogical and geochemical properties of bedrock and regolith materials from different geological provinces and regions with contrasting landscape histories.
Minty, Brian; Franklin, Ross; Milligan, Peter; Richardson, Murray; Wilford, John
Modeling radiometric effects on airborne multispectral videography
NASA Astrophysics Data System (ADS)
Observing the Earth through remote technologies allows for the extraction of synoptic data that is difficult to match with ground-based measurements. Over time, remote sensing instruments and associated processing algorithms have improved in both spectral and spatial resolution. Currently, commercial spaceborne and airborne imaging systems are capable of producing data at one-meter spatial resolution. To fully utilize these improved data sources, it is critical that processing and analysis algorithms keep pace with instrument advances. This dissertation describes models and algorithms used to correct high spatial resolution airborne imagery for radiometric effects. These radiometric effects include topography and view-angle (also termed bidirectional reflectance). Also studied were radiometric and geometric calibration issues. The sensor used for this study was a four camera off-the-shelf system which is capable of collecting imagery in the visible through near-infrared (0.4-1.0 ?m) spectral region. Three topographic correction models were applied to one- meter spatial resolution imagery collected over Fort Huachuca, Arizona, in October 1998. The model proposed by Ekstrand (1996) was successful in reducing topographic effects found in the semidesert grassland and Madrean forest communities. Spectral signature coefficient of variation, histogram range, and histogram normality all showed improvement after correction for both classes. Additionally, the optimal spatial resolution of the supporting Digital Elevation Model (DEM) was found to be 40 meters. This disagrees with previous research stating that the imagery to be corrected and the supporting DEM should be the same spatial resolution. Two bidirectional reflectance models were applied to 1.5 meter spatial resolution imagery collected over Parramore Island, Virginia, in May 1999. A modified version of a model proposed by Irons et al. (1991) was found to substantially reduce bidirectional reflectance effects over four vegetation communities. Spectral signature coefficient of variation and overlap pixel difference showed improvement after correction. Additionally, an unsupervised technique was developed to generate training data for model coefficient generation. This technique produces a large amount of training points, is relatively free of user bias, and can be used as a masking procedure to apply the correction models to the appropriate land- cover classes. Finally, the computational aspects of mosaic construction and sensor orientation calculation were examined. A distributed approach for pass-point generation was developed utilizing off-the-shelf hardware and software. The use of six processors was found to improve performance by a factor of 5.2 (measured by calculation time) when compared to a single processor. Products developed as part of the computational process are discussed. These included orthomosaics, anaglyphs, and digital elevation models. The radiometric correction models studied should be extendable to any high spatial resolution (airborne or spaceborne) multispectral or hyperspectral system. The end-to-end processing routines developed as part of this study will substantially increase the data throughput of digital multispectral videography systems.
Fischer, Robert L., Jr.
Suomi-NPP CrIS radiometric calibration uncertainty
NASA Astrophysics Data System (ADS)
Cross-track Infrared Sounder (CrIS) is the high spectral resolution spectroradiometer on the Suomi National Polar-Orbiting Partnership (NPP) satellite, providing operational observations of top-of-atmosphere thermal infrared radiance spectra for weather and climate applications. This paper describes the CrIS radiometric calibration uncertainty based on prelaunch and on-orbit efforts to estimate calibration parameter uncertainties, and provides example results of recent postlaunch validation efforts to assess the predicted uncertainty. Prelaunch radiometric uncertainty (RU) estimates computed for the laboratory test environment are less than ~0.2 K 3 sigma for blackbody scene temperatures above 250 K, with primary uncertainty contributions from the calibration blackbody temperature, calibration blackbody reflected radiance terms, and detector nonlinearity. Variability of the prelaunch RU among the longwave band detectors and midwave band detectors is due to different levels of detector nonlinearity. A methodology for on-orbit adjustment of nonlinearity correction parameters to reduce the overall contribution to RU and to reduce field of view (FOV)-to-FOV variability is described. The resulting on-orbit RU estimates for Earth view spectra are less than 0.2 K 3 sigma in the midwave and shortwave bands, and less than 0.3 K 3 sigma in the longwave band. Postlaunch validation efforts to assess the radiometric calibration of CrIS are underway; validation results to date indicate that the on-orbit RU estimates are representative. CrIS radiance products are expected to reach "Validated" status in early 2014.
Tobin, David; Revercomb, Henry; Knuteson, Robert; Taylor, Joe; Best, Fred; Borg, Lori; DeSlover, Dan; Martin, Graeme; Buijs, Henry; Esplin, Mark; Glumb, Ronald; Han, Yong; Mooney, Daniel; Predina, Joe; Strow, Larrabee; Suwinski, Lawrence; Wang, Likun
An intercomparison study of luminescence dating protocols and techniques applied to medieval brick samples from Normandy (France)
A luminescence dating study has been applied to inform the history and archaeology of two early medieval buildings in north western France. Five bricks were sampled from the medieval churches (10th�11th centuries A.D.) of Rugles and Cond�-sur-Risle in Normandy. The samples were divided and tested in the luminescence laboratories of the University of Durham (UK) and of Iramat-CRP2A, University of
Sophie Blain; Ian K. Bailiff; Pierre Guibert; Armel Bouvier; Maylis Bayl�
Building on previous OSL dating techniques for gypsum: a case study from Salt Basin playa, New Mexico and Texas
The long term stability and reliability of the luminescence signal for gypsum has not been well documented or systematically measured until just recently. A review of the current literature for luminescence dating of gypsum is compiled here along with original efforts at dating an intact and in-situ bed of selenite gypsum at Salt Basin Playa, New Mexico and Texas. This effort differs from other documented luminescence dating efforts because the gypsum is not powdery or redistributed from its original growth patterns within the playa basin but is instead of a crystalline form. Sixteen ages from eight cores were ultimately produced with seven of the ages coming from rare detrital quartz encased in or with the gypsum crystals while the remaining ages are from the crystalline gypsum. As far as can be ascertained, the quartz was measured separately from the gypsum and no contaminants were noted in any of the aliquots. Some basic and preliminary tests of signal stability were measured and found to be mitigated by lessening of pre-heat protocols. Ages ranged from 8 ka to 10 ka in the shallow cores and 16 ka to 22 ka in the deeper cores. These ages will be useful in determining rates of gypsum growth within a sequence of evaporates which, in turn, will help to better document historic rates of evaporation and thus estimate, with more precision, the corresponding annual evaporation rates.
Mahan, Shannon; Kay, John
ERIC Educational Resources Information Center
Dating violence is a form of student-on-student victimization and is a serious school safety issue. Research indicates that at a minimum, 10 percent of high school students are victims of dating violence in one form or another. Among female high school students that date, some data indicate that as many as 30 percent may be victims of dating�
Stader, David L.
Monitoring and assessment on radiometric stability of HJ-1A CCD using MODIS data
NASA Astrophysics Data System (ADS)
Regular monitoring and assessment on radiometric performance of satellite sensors is necessary for the quantitative remote sensing application and development. HJ satellite was launched by China on 2008, which was put forward to achieve dynamic monitoring of environment and disasters, also need to monitor radiometric performance and provide stable and reliable calibration coefficients timely. In this study, Terra/MODIS data were used to calibrate HJ-1A CCD camera by cross-calibration technique in Dunhuang radiometric calibration site. Total thirteen HJ -1A CCD images were utilized, the 6s model was used to estimate the spectral matching factors. Finally, this study obtains long-term HJ-1A CCD calibration coefficients from 2009 to 2012. Results show that each band of HJ-1A CCD is varying degrees of degradation after HJ satellites launched 5 years later. This study is helpful to obtain high accuracy and reliable calibration coefficients and monitor radiometric performance of HJ-1A CCD.
Chen, Guan-wen; Chen, Zheng-chao; Ma, Long; Zhang, Hao
Radiometric calibration of Advanced Land Imager using reflectance-based results between 2001 and 2005
The Landsat series of sensors have supplied the remote sensing community with a continuous data set dating to the early 1970s. An important aspect of retaining the continuity of these data is that a Landsat follow-on as well as current Landsat instruments must be understood radiometrically throughout their mission. The Advanced Land Imager (ALI), for example, was developed as a
J. McCorkel; K. Thome; S. Biggar; M. Kuester
Thermoluminescence (TL) dating
NSDL National Science Digital Library
Thermoluminescence (TL) dating is an important technique used to determine the ages of some ancient earth materials; in this case, sediments and certain ancient artifacts. TL energy is stored in the form of trapped electrons and quartz sand is the most commonly used mineral employed in the dating process. Topics which are discussed include basic principles of TL dating, sampling techniques and strategies, sample processing, dateable material, cost and turnaround time, other applications, and associated literature.
Price, David
Microwave radiometric observations of snowpacks
NASA Technical Reports Server (NTRS)
Models for the microwave emission from snowpacks were generated on the basis of radiometric observations made at 10.7 GHz, 37 HGz, and 94 GHz at a test site near Steamboat Springs, Colorado. In addition to conducting measurements on an approximately daily basis over a six week observation period, measurements were made over several diurnal cycles during which the change in snow wetness was tracked by the microwave radiometers. Also, the variation in emissivity with snow water equivalent was examined, as was the sensitivity to changes in snow surface geometry. The microwave emissivity was observed to (1) decrease exponentially with snow water equivalent and (2) increase with snow wetness. Thus, the emission behavior is the reverse of the backscattering behavior observed by the radar. By fitting the models to the measured data, the variation of the optical depth with snow wetness was estimated.
Ulaby, F. T.; Stiles, W. H.
Radiometric correction of LANDSAT data
NASA Technical Reports Server (NTRS)
The author has identified the following significant results. The six independent sensors of the multispectral band scanner are supposed to be identical; however, in actual practice, they may have different gain settings and offset factors, which result in the effect known as stripping (black lines at regular intervals) of the imagery. A simple two parameter method to correct the gain settings and offset factors of each of the sensors with respect to one sensor, taken as reference, was developed. This method assumes: (1) the response of a detector varies linearly with the radiance of radiation received, and (2) the means, as well as the standard deviations, of a reasonably large number of pixels, in a given wavelength band, are equal for each of the detectors for the radiometrically corrected data.
Dejesusparada, N.; Kumar, R. (principal investigator); Cavalcanti, L. A.
Absolute Radiometric Calibration of SERTS
NASA Astrophysics Data System (ADS)
The Solar EUV Rocket Telescope and Spectrograph (SERTS) obtains imaged high-resolution spectra of individual solar features, providing information about the Sun's corona and upper transition region. We have recently carried out a complete end-to-end calibration of the instrument to determine its absolute radiometric response over the full bandpass of 300 -- 365 Angstroms. The measurements were done at the Rutherford-Appleton Laboratory (RAL) in England, using the same vacuum facility and EUV radiation source used in the pre-flight calibration of the Coronal Diagnostic Spectrometer (CDS) experiment now flying aboard the SOHO spacecraft. For our SERTS project, the unique radiation source provided by the Physikalisch-Technische Bundesanstalt (PTB) in Germany was re-calibrated to an absolute accuracy of 7% (1sigma ) at 12 wavelengths covering our bandpass directly against the Berlin electron storage ring BESSY, which is a primary radiometric source standard. Scans of the SERTS aperture over a range of pitch and yaw angles were made to determine the instrument's absolute spectral sensitivity to <= 25%, considering all sources of error. These results will be matched against prior calibrations which relied on combining measurements of individual optical components, and on comparisons with theoretically predicted `insensitive' line ratios. The recent measurements at RAL also give information about the uniformity of illumination across the collimated source beam, as well as about polarization characteristics of both the instrument and radiation source, which may prove helpful in correctly interpreting the original CDS calibration data. We hope to repeat such calibration measurements and to provide future SERTS flights annually, at least throughout the duration of the SOHO mission. Coordinated observing programs would then allow these updated absolute calibrations to be transferred on a regular basis to several of the instruments onboard SOHO, including CDS, EIT, and CELIAS.
Thomas, R. J.; Condor, C. E.; Haas, J. P.; Linard, D. L., II; Swartz, M.; Kent, B. J.; Hollandt, J.
... Parents of Teens Crime, Teens, and Trauma Assault Bullying and Harassment Child Sexual Abuse Dating Violence Sexual ... Parents of Teens Crime, Teens, and Trauma Assault Bullying and Harassment Child Sexual Abuse Dating Violence Sexual ...
Radiometric calibration of an airborne chemical imager
NASA Astrophysics Data System (ADS)
Advances made over the past decade in multispectral and hyperspectral imaging systems, have led to a wide range of new remove sensing capabilities, including the ability to detect and image chemical vapors in the atmosphere. This sensor has application in the detection and monitoring of chemical weapons, as well as environmental pollution monitoring. Key to the continuing development of this technology is accurate and temporally stable radiometric calibration. This paper presents an overview of the system level radiometric calibration approach used for the SAFEGUARD multispectral infrared line scanner. This approach includes radiometric calibration of the sensor at the aperture, corrections for atmospheric effects and group truth validation.
Zywicki, Randall W.
Radiocarbon dating can be used to determine the age of objects that contain components that were once alive. In the case of human remains, a radiocarbon date can distinguish between a crime scene and an archeological site. Documents, museum artifacts and art objects can be dated to determine if their age is correct for the historical context. A radiocarbon date does not confirm authenticity, but it can help identify a forgery.
Buchholz, B A
Photometric and Near Infrared Radiometric Measurement Systems.
National Technical Information Service (NTIS)
This report describes the details of calibration, operation, and constraints of a photometric and a 0.73-0.97 micrometers near infrared radiometric measurement system, both constructed at NAVWPNSUPPCEN Crane for measurements of flare plume candlepower and...
F. L. Burton C. E. Dinerman
Surface aerosol radiative forcing derived from collocated ground-based radiometric observations during PRIDE, SAFARI, and ACE-Asia.
An approach is presented to estimate the surface aerosol radiative forcing by use of collocated cloud-screened narrowband spectral and thermal-offset-corrected radiometric observations during the Puerto Rico Dust Experiment 2000, South African Fire Atmosphere Research Initiative (SAFARI) 2000, and Aerosol Characterization Experiment-Asia 2001. We show that aerosol optical depths from the Multiple-Filter Rotating Shadowband Radiometer data match closely with those from the Cimel sunphotometer data for two SAFARI-2000 dates. The observed aerosol radiative forcings were interpreted on the basis of results from the Fu-Liou radiative transfer model, and, in some cases, cross checked with satellite-derived forcing parameters. Values of the aerosol radiative forcing and forcing efficiency, which quantifies the sensitivity of the surface fluxes to the aerosol optical depth, were generated on the basis of a differential technique for all three campaigns, and their scientific significance is discussed. PMID:14526843
Hansell, Richard A; Tsay, Si-Chee; Ji, Qiang; Liou, K N; Ou, Szu-Cheng
Total ozone and aerosol optical depths inferred from radiometric measurements in the Chappuis absorption band
A second-derivative smoothing technique, commonly used in inversion work, is applied to the problem of inferring total columnar ozone amounts and aerosol optical depths. The application is unique in that the unknowns (i.e., total columnar ozone and aerosol optical depth) may be solved for directly without employing standard inversion methods. It is shown, however, that by employing inversion constraints, better solutions are normally obtained. The current method requires radiometric measurements of total optical depth through the Chappuis ozone band. It assumes no a priori shape for the aerosol optical depth versus wavelength profile and makes no assumptions about the ozone amount. Thus, the method is quite versatile and able to deal with varying total ozone and various aerosol size distributions. The technique is applied first in simulation, then to 119 days of measurements taken in Tucson, Arizona, that are compared to TOMS values for the same dates. The technique is also applied to two measurements taken at Mauna Loa, Hawaii, for which Dobson ozone values are available in addition to the TOMS values, and the results agree to within 15%. It is also shown through simulations that additional information can be obtained from measurements outside the Chappuis band. This approach reduces the bias and spread of the estimates total ozone and is unique in that it uses measurements from both the Chappuis and Huggins absorption bands. 12 refs., 6 figs., 2 tabs.
Flittner, D.E.; Herman, B.M.; Thome, K.J.; Simpson, J.M.; Reagan, J.A. (Univ. of Arizona, Tucson (United States))
Investigation of Pre and Post-Flight Radiometric Calibration Uncertainties from Surface Based Measurements
A new technique has been developed for inferring column ozone amounts and aerosol optical depths from zenith sky observations. A new radiometric calibration technique for large aperture remote sensing instruments observing the earth through space has been validated which subsequently increased the accuracy of remote sensing measurements of ozone and vertical profiles using measurements of back-scattered ultraviolet solar radiation.
D. F. Heath; Z. Y. Wei; Z. Ahman
Investigation of Pre- and Post-Flight Radiometric Calibration Uncertainties from Surface Based Measurements
A new technique has been developed for inferring column ozone amounts and aerosol optical depths from zenith sky observations. A new radiometric calibration technique for large aperture remote sensing instruments observing the earth through space has been validated which subsequently increased the accuracy of remote sensing measurements of ozone and vertical profiles using measurements of back-scattered ultraviolet solar radiation.
Heath, D.F.; Wei, Z.Y.; Ahman, Z.
NASA Astrophysics Data System (ADS)
This chapter provides a necessarily brief summary of radioactive dating techniques, which can produce dates (�ages�) ranging from tens to thousands through millions to billions of years often with assumptions not universally accepted, especially those involving the assessments of half-lives and radioactive decay constants.
Bowen, R.
Fission track dating of kimberlitic zircons
The only reliable method for dating kimberlites at present is the lengthy and specialized hydrothermal procedure that extracts 206Pb and 238U from low-uranium zircons. This paper describes a second successful method by fission track dating of large single-crystal zircons, 1.0-1.5 cm in dimension. The use of large crystals overcomes the limitations imposed in conventional fission track analysis which utilizes crushed fragments. Low track densities, optical track dispersion, and the random orientation of polished surfaces in the etch and irradiation cycle are effectively overcome. Fission track ages of zircons from five African kimberlites are reported, from the Kimberley Pool (90.3 ?? 6.5 m.y.), Orapa (87.4 ?? 5.7 and 92.4 ?? 6.1 m.y.), Nzega (51.1 ?? 3.8 m.y.), Koffiefontein (90.0 ?? 8.2 m.y.), and Val do Queve (133.4 ?? 11.5 m.y.). In addition we report the first radiometric ages (707.9 ?? 59.6 and 705.5 ?? 61.0 m.y.) of crustal zircons from kimberlites in northwest Liberia. The fission track ages agree well with earlier age estimates. Most of the zircons examined in this study are zoned with respect to uranium but linear correlations are established (by regression analysis) between zones of variable uranium content, and within zones of constant uranium content (by analysis of variance). Concordance between the fission track method and the U/Pb technique is established and we concluded that track fading from thermal annealing has not taken place. Kimberlitic zircons dated in this study, therefore, record the time of eruption. ?? 1983.
Haggerty, S. E.; Raber, E.; Naeser, C. W.
Radiometric surveys in underground environment
NASA Astrophysics Data System (ADS)
Due to their ability to travel through the air for several metres, gamma-rays emitted from natural radioactive elements can be successfully used in surveys carried out both with airborne and ground equipments. Besides the concentration of the radio-elements contained in rocks and soils and the intrinsic characteristics of the gamma-ray detector, the detected count rate depends on the solid angle around the spectrometer. On a flat outcrop, ground spectrometry detects the radiation ideally produced by a cylindrical mass of rock of about two metres in diameter and thickness of about half a meter. Under these geometrical conditions, the natural radioactivity can be easily evaluated. With operating conditions different from the standard ones, such as at the edge of an escarpment, the count rate halves because of the missing material, whereas in the vicinity of a rock wall the count rate will increase. In underground environment, the recorded count rate may even double and the in situ assessment of the concentration of radio-elements may be rather difficult, even if the ratios between the different radio-elements may not be affected. We tested the applicability of gamma-ray spectrometry for rapid assessment of the potential hazard levels related to radon and radiation dose rate in underground environment. A mine shaft, located in a zone of uranium enrichment in Liguria (Italy), has been investigated. A preliminary ground radiometric survey was carried out to define the extent of the ore deposit. Then, the radiometric investigation was focussed on the mine shaft. Due to rock mass above the shaft vault, the background gamma radiation can be considered of negligible influence on measurements. In underground surveys, besides deviations from a flat geometry, factors controlling radon exhalation, emanation and stagnation, such as fractures, water leakage and the presence of ventilation, should be carefully examined. We attempted to evaluate these control factors and collected a set of rock samples along the mine shaft to compare in situ results with high resolution gamma-ray analysis in the laboratory. The comparison points to a systematic overestimation (on the average, by a factor of two) of the uranium, thorium and potassium concentrations obtained with the portable apparatus. The bias between laboratory and field is slightly smaller for potassium and could be due only to deviation from standard geometric conditions. The largest differences occur in uranium concentrations, probably due also to the influence of the activity deriving from radon stagnation. The calculated radon flux depends on the radium specific activity, which, under the assumption of secular radioactive equilibrium, can be easily inferred from the uranium concentration, and the specific exhalation coefficient. Measurements of specific exhalation coefficient are difficult and only few studies have examined unaltered rocks in details. We estimated the values of this parameter by considering the degree of fracturing, width of fissures and evidence of percolating groundwater. In general, the coefficient increases from the entrance, where rocks are more massive, towards the shaft bottom, where closely spaced open fissures, often filled with percolating groundwater, might boost exhalation. As a whole, both potential radon flux and radiation dose values are relevant to radio protection rules.
Bochiolo, Massimo; Chiozzi, Paolo; Verdoya, Massimo; Pasquale, Vincenzo
Dendrochemical Dating of Tephra Layers
Dating eruptions in the past 1000 years can be difficult with 14C, as production rates have varied. Tree-ring dating has been used, with eruptions presumably causing thin rings. We are developing a dendrochemical dating technique that may give more confidence to such dates. When a tephra is deposited, soil chemistry may change and many components of the glassy matrix are
M. H. Ort; P. R. Sheppard; J. Speakman; K. A. Anderson; M. D. Elson; C. Siebe G
Earth Observing-1 Advanced Land Imager: Radiometric Response Calibration
NASA Technical Reports Server (NTRS)
The Advanced Land Imager (ALI) is one of three instruments to be flown on the first Earth Observing mission (EO-1) under NASA's New Millennium Program (NMP). ALI contains a number of innovative features, including a wide field of view optical design, compact multispectral focal plane arrays, non-cryogenic HgCdTe detectors for the short wave infrared bands, and silicon carbide optics. This document outlines the techniques adopted during ground calibration of the radiometric response of the Advanced Land Imager. Results from system level measurements of the instrument response, signal-to-noise ratio, saturation radiance, and dynamic range for all detectors of every spectral band are also presented.
Mendenhall, J. A.; Lencioni, D. E.; Evans, J. B.
Cropland measurement using Thematic Mapper data and radiometric model
NASA Technical Reports Server (NTRS)
To halt erosion and desertification, it is necessary to quantify resources that are affected. Necessary information includes inventory of croplands and desert areas as they change over time. Several studies indicate the value of remote sensor data as input to inventories. In this study, the radiometric modeling of spectral characteristics of soil and vegetation provides the theoretical basis for the remote sensing approach. Use of Landsat Thematic Mapper images allows measurement of croplands in Saudi Arabia, demonstrating the capability of the approach. The inventory techniques and remote sensing approach presented are potentially useful in developing countries.
Lyon, John G.; Khuwaiter, I. H. S.
NSDL National Science Digital Library
This is an interactive exercise about Geologic Time. It focuses on how geologists and archaeologists determine the ages of rocks and ancient artifacts. This is a beta release of an instructional activity still under development. Virtual Dating contains two modules as well as a demonstration version. One module is Virtual Dating Isochron for rocks and minerals and the other is Virtual Dating Radiocarbon (Carbon-14). The interactive modules involve the students in exploring data and background information and answering questions as they move through the activity. An answer checking and feedback function is employed. There is also a Virtual Dating Demo if you want to do a quick run-through of the activity without answer checking enabled.
Novak, Gary
Ground-Water Potential: A Predictive Model from Airborne Geophysical, Radiometric, and Remote Sensing Data, Cear�, Brazil
Preliminary results are presented that map locations permissive for ground-water resources in crystalline bedrock from airborne magnetic, electromagnetic, radiometric, and Landsat 7-ETM+ data. Predictive models were generated using the probability ratio method, a raster-based GIS technique. Results distinguish preferential values of magnetic, electromagnetic, radiometric data, and Fe, OH minerals in soil that characterize rocks where low- and high- yield wells
Anne Elizabeth McCafferty; Adalene Moreira Silva; M�nica Mazzini Perrotta
First SIMBIOS Radiometric Intercomparison (SIMRIC-1), April-September 2001.
National Technical Information Service (NTIS)
This report describes the first SIMBIOS (Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies) Radiometric Intercomparison (SIMRIC-1). The purpose of the SIMRIC-1 is to ensure a common radiometric scale of the calibration...
C. Davis C. McClain D. Korwan G. Fargion G. Meister J. Cooper M. Godin P. Abel R. Barnes R. Maffione
A double-spike method for K-Ar measurement: A technique for high precision in situ dating on Mars and other planetary surfaces
NASA Astrophysics Data System (ADS)
A new method for K-Ar dating using a double isotope dilution technique is proposed and demonstrated. The method is designed to eliminate known difficulties facing in situ dating on planetary surfaces, especially instrument complexity and power availability. It may also have applicability in some terrestrial dating applications. Key to the method is the use of a solid tracer spike enriched in both 39Ar and 41K. When mixed with lithium borate flux in a Knudsen effusion cell, this tracer spike and a sample to be dated can be successfully fused and degassed of Ar at <1000 �C. The evolved 40Ar?/39Ar ratio can be measured to high precision using noble gas mass spectrometry. After argon measurement the sample melt is heated to a slightly higher temperature (�1030 �C) to volatilize potassium, and the evolved 39K/41K ratio measured by Knudsen effusion mass spectrometry. Combined with the known composition of the tracer spike, these two ratios define the K-Ar age using a single sample aliquot and without the need for extreme temperature or a mass determination. In principle the method can be implemented using a single mass spectrometer. Experiments indicate that quantitative extraction of argon from a basalt sample occurs at a sufficiently low temperature that potassium loss in this step is unimportant. Similarly, potassium isotope ratios measured in the Knudsen apparatus indicate good sample-spike equilibration and acceptably small isotopic fractionation. When applied to a flood basalt from the Viluy Traps, Siberia, a K-Ar age of 351 � 19 Ma was obtained, a result within 1% of the independently known age. For practical reasons this measurement was made on two separate mass spectrometers, but a scheme for combining the measurements in a single analytical instrument is described. Because both parent and daughter are determined by isotope dilution, the precision on K-Ar ages obtained by the double isotope dilution method should routinely approach that of a pair of isotope ratio determinations, likely better than �5%.
Farley, K. A.; Hurowitz, J. A.; Asimow, P. D.; Jacobson, N. S.; Cartwright, J. A.
Radiometric-microbiologic assay of niacin using Kloeckera brevis: analysis of human blood and food
Kloeckera brevis, a yeast, was used as the test organism for the development of a radiometric-microbiologic (RMA) assay for niacin. The assay was determined to be sensitive to the 2 ng niacin per vial level and specific for the biologically active forms of this vitamin. The method was shown to be simple, accurate, and precise in the analysis of niacin in human blood and food. The application of the radiometric technique eliminates some of the problems encountered with conventional turbidimetric-microbiologic assay.
Guilarte, T.R.; Pravlik, K.
The multi-temporal comparisons from high resolution KOMPSAT-2 image with dehaze and radiometric normalization methods
NASA Astrophysics Data System (ADS)
The KOrea MultiPurpose SAtellite-2 (KOMPSAT-2) satellite developed by Korea Aerospace Research Institute (KARI) was launched on July 28, 2006 in northern Russia and has continued successful operations for almost 4 years past the initial mission. KOMPSAT-2 has been providing 1-m resolution of panchromatic images and 4-m resolution multi spectral images all over the world. In the case optical satellites, haze is considered as an unwanted obstacle when estimating surface information. Usually, it is masked with subjective threshold method to reduce contaminated area which may give wrong information to user. In this study, haze transformation is applied for determining haze area and inferring surface digital number of KOMPSAT-2 under haze condition. When comparing differently observed images, radiometric normalized is the essential process to interpret variations of surface phenomena, especially in land surface change detection. There are mainly two kinds of methods to correct the different radiometric values. One is the absolute radiometric normalization intending for trying to estimate the actual surface reflectance, and another is relative radiometric normalization, which is linearly rectifying the observed image at the specific time to the others at different time for common radiometric scale. In this study, relative radiometric normalization method is used for correcting differences among images caused by inconsistent observation condition. When normalizing multi-date images, BRDF (Bidirectional Reflectance Distribution Function) also considered for reducing anisotropy effects caused by relative solar-sensor-target geometry. Processed surface reflectance based on dehazing and radiometric normalization show better results when comparing multi-date images than original reflectance images.
Yeom, J.; Kim, H.; Kim, Y.; Kim, J.
Geometric and radiometric characterization of LANDSAT-D thematic mapper and multispectral scanner data
NASA Technical Reports Server (NTRS)
A geometrically raw image of Washington, D.C. was acquired and radiometrically corrected. The data show little of the detector stripping common in earlier MSS images. The radiometrically corrected data have uniform means and standard deviations for the detectors in each band; however, the data for different detectors utilize a different pattern of DN levels, resulting in ubiquitous stripping of 1 DN amplitude. Band-to-band registration was assessed using color composites and small area correlation techniques. The spectral equivalency of the first four bands of the thematic mapper with the four bands of the MSS is being examined. Geometric analysis of the Washington, D.C. scene have started and a generalized routine for examining the contents of the label files and nonvideo data files was implemented. Several discrepancies from the documentation are described. Night scenes and daytime ocean scenes required for radiometric purposes were identified and the data ordered.
Kieffer, H. H. (principal investigator)
MODIS Cloud Optical Property Retrieval Uncertainties Derived from Pixel-Level Radiometric Error Estimates
NASA Technical Reports Server (NTRS)
MODIS retrievals of cloud optical thickness and effective particle radius employ a well-known VNIR/SWIR solar reflectance technique. For this type of algorithm, we evaluate the uncertainty in simultaneous retrievals of these two parameters to pixel-level (scene-dependent) radiometric error estimates as well as other tractable error sources.
Platnick, Steven; Wind, Galina; Xiong, Xiaoxiong
MODIS Cloud Optical Property Retrieval Uncertainties Derived from Pixel-Level VNIR/SWIR Radiometric Uncertainties
NASA Technical Reports Server (NTRS)
Moderate Resolution Imaging Spectroradiometer (MODIS) retrievals of optical thickness and effective particle radius for liquid water and ice phase clouds employ a well-known VNIR/ SWIR solar reflectance technique. For this type of algorithm, we evaluate the quantitative uncertainty in simultaneous retrievals of these two cloud parameters to pixel-level radiometric calibration estimates and other fundamental (and tractable) error sources.
Platnick, S.; Wind, G.; Xiong, X.
Amino acid racemization dating of Upper Pleistocene - Holocene terrestrial gastropods from a Mediterranean region (Murcia, SE Spain)
NASA Astrophysics Data System (ADS)
The amino acid racemization method has become a widely used geochronological tool for dating Quaternary deposits. The method is based on the fact that living organisms contain only L-amino acids which gradually racemize into D-amino acids after death. Thus, the D/L ratio increases with time after death until it is equal to 1, that is, when equilibrium is reached. Gastropod shells are particularly useful for amino acid racemization dating. Because the amino acid racemization method is not a numerical dating method in isolation, it needs to be calibrated, mainly with radiometric dating methods. The racemization process is genus- and temperature-dependent. In this work we present a preliminary analysis that compares the radiometric age estimated from different dating methods of a number of gastropods recovered in localities from Murcia (Southeastern Spain), with the age obtained through the amino acid racemization method. Taking advantage of recent paleoseismological research in the Murcia region (SE Spain), 28 gastropods specimens were collected from different trenches dug in young Quaternary alluvial deposits. The specimens were subsequently classified and then analyzed according to the standards protocols of the Biomolecular Stratigraphy Laboratory (UPM, Madrid School of Mines). The species found were Otala lactea, Iberus gualterianus, Sphincterochila candidissima and Theba pisana. The D/L ratios of aspartic acid, leucine, phenylalanine and glutamic acid were determined, and the corresponding average age of each specimen was calculated introducing the D/L values in the age calculation algorithm of Torres et al. (1997) for gastropods of central and southern Spain. The racemization age for each locality was then compared to the radiometric age of the deposit where the specimens were collected. To this respect, the samples were classified in different groups considering the reliability on the age control method. The most reliable sample consists only on dates obtained by the radiocarbon method applied to pieces of charcoal found in the same sedimentary unit as the gastropod. The other subsets consider dates, or bracketed dates, obtained from other dating techniques (TL, OSL, Uranium series) or even stratigraphic criteria. Preliminary results show that Torres et al. (1997) calibration algorithm estimates ages as much as ten times older than the most likely one. We think that this result is due to a strong bias on the way the algorithm was obtained, based mostly in Lower Pleistocene/Pliocene samples. Hence, the new data presented here could be used to constraint better the Torres et al. (1997) function towards Upper Pleistocene and Holocene dates. This type of calibration model would be very valuable in determining ages of recent deposits in the Murcia Region, a matter that is critical in paleoseismological research.
Garcia-Mayordomo, Julian; Ortiz, Jose E.; Torres, Trinidad; Insua-Arevalo, Juan M.; Martinez-Diaz, Jose J.; Altolaguirre, Yul; Canales-Fernandez, Maria L.; Martin-Banda, Raquel
Reduction of radiometric miscalibration--applications to pushbroom sensors.
The analysis of hyperspectral images is an important task in Remote Sensing. Foregoing radiometric calibration results in the assignment of incident electromagnetic radiation to digital numbers and reduces the striping caused by slightly different responses of the pixel detectors. However, due to uncertainties in the calibration some striping remains. This publication presents a new reduction framework that efficiently reduces linear and nonlinear miscalibrations by an image-driven, radiometric recalibration and rescaling. The proposed framework-Reduction Of Miscalibration Effects (ROME)-considering spectral and spatial probability distributions, is constrained by specific minimisation and maximisation principles and incorporates image processing techniques such as Minkowski metrics and convolution. To objectively evaluate the performance of the new approach, the technique was applied to a variety of commonly used image examples and to one simulated and miscalibrated EnMAP (Environmental Mapping and Analysis Program) scene. Other examples consist of miscalibrated AISA/Eagle VNIR (Visible and Near Infrared) and Hawk SWIR (Short Wave Infrared) scenes of rural areas of the region Fichtwald in Germany and Hyperion scenes of the Jalal-Abad district in Southern Kyrgyzstan. Recovery rates of approximately 97% for linear and approximately 94% for nonlinear miscalibrated data were achieved, clearly demonstrating the benefits of the new approach and its potential for broad applicability to miscalibrated pushbroom sensor data. PMID:22163960
Rogass, Christian; Spengler, Daniel; Bochow, Mathias; Segl, Karl; Lausch, Angela; Doktor, Daniel; Roessner, Sigrid; Behling, Robert; Wetzel, Hans-Ulrich; Kaufmann, Hermann
Effects of foam on ocean surface microwave emission inferred from radiometric observations of reproducible breaking waves
WindSat, the first satellite polarimetric microwave radiometer, and the NPOESS Conical Microwave Imager\\/Sounder both have as a key objective the retrieval of the ocean surface wind vector from radiometric brightness temperatures. Available observations and models to date show that the wind direction signal is only 1-3 K peak-to-peak at 19 and 37 GHz, much smaller than the wind speed signal.
Sharmila Padmanabhan; Steven C. Reising; William E. Asher; L. Allen Rose; Peter W. Gaiser
What Is Date Rape? When people think of rape , they might picture a stranger jumping out of a shadowy place and attacking someone. ... things that you can do: Immediately After a Rape If you're hurt, go straight to the ...
Radiometric Bode's law and Extrasolar Planets.
National Technical Information Service (NTIS)
We predict the radio flux densities of the extrasolar planets in the current census, making use of an empirical relation the radiometric Bode's law determined from the five 'magnetic' planets in the solar system (the Earth and the four gas giants). Radio ...
E. Greenlees E. Hogan J. Dietrick T. J. Lazio W. M. Farrell
Robust stable radiometric fingerprinting for wireless devices
We introduce a new method for radiometric fingerprinting that detects the unique variations in the antenna, oscillator properties, as well as the digital and analog interfaces of the radio by passively monitoring the radio packets. Several individual identifiers are used for extracting the unique physical characteristics of the radio, including the frequency offset, modulated phase offset, in-phase\\/quadrature-phase offset from the
Andrea Candore; Ovunc Kocabas; Farinaz Koushanfar
Ocean color remote sensing systems - Radiometric requirements
NASA Technical Reports Server (NTRS)
A methodology for specifying the radiometric requirements for ocean color remote sensing systems is described. Consideration is given to the noise equivalent radiance, the saturation radiance, the polarization sensitivity, and the calibration and stability. The degree of polarization across a scan line for the CZCS and MODIS orbits is presented.
Gordon, Howard R.
Radiometric terrain correction of SPOT5 image
NASA Astrophysics Data System (ADS)
Remote sensing SPOT5 images have been widely applied to the surveying of agriculture and forest resources and to the monitoring of ecology environment of mountain areas. However, the accuracy of land-cover classification of mountain areas is often influenced by the topographical shadow effect. Radiometric terrain correction is important for this kind of application. In this study, a radiometric terrain correction model which based on the rationale of moment matching was made in ERDAS IMAGINE by using the Spatial Modeler Language. Lanxi city in China as the study area, a SPOT5 multispectral image with the spatial resolution of 10 m of that mountain area was corrected by the model. Furthermore, in order to present the advantage of this new model in radiometric terrain correction of remote sensing SPOT5 image, the traditional C correction approach was also applied to the same area to see its difference with the result of the radiometric terrain correction model. The results show that the C correction approach keeps the overall statistical characteristics of spectral bands. The mean and the standard deviation value of the corrected image are the same as original ones. However, the standard deviation value became smaller by using the radiometric terrain correction model and the mean value changed accordingly. The reason of these changes is that before the correction, the histogram of the original image is represented as the 'plus-skewness distribution' due to the relief-caused shade effect, after the correction of the model, the histogram of the image is represented as the normal distribution and the shade effect of the relief has been removed. But as for the result of the traditional C approach, the skewness of the histogram remains the same after the correction. Besides, some portions of the mountain area have been over-corrected. So in my study area, the C correction approach can't remove the shade effect of the relief ideally. The results show that the radiometric terrain correction model based on the rationale of moment matching is an effective model to reduce the shade effect than the traditional C correction approach, especially in the complex undulation of mountain area with lots of shade effect. In other words, the traditional C correction approach will show the better result at the plain area with less shade effect. Besides, the accuracy of the DEM data and the registration accuracy between the image and the DEM data will also influence the final correction accuracy. In order to achieve the higher radiometric terrain correction, high spatial resolution DEM data is preferred.
Feng, Xiuli; Zhang, Feng; Wang, Ke
NASA Astrophysics Data System (ADS)
This chapter presents the different methods used or potentially useful to determine the age of an impact event on terrestrial planets or meteorite parent bodies. Two approaches exist: (1) geological methods such as Stratigraphy, which is the study of succeeding geological events, and (2) methods based on natural radioactivity (radiometric dating), as well as the measurement of isotopes produced by cosmic rays in space or on the Earth's surface. The nuclear methods are preferentially discussed because they yield absolute ages, whereas geological methods define relative ages only. Shock metamorphic effects on minerals and rocks are presented in the frame of an impact crater. The different phase transformations induced by shock wave passage are typical for high-pressure regimes (20-60 GPa) which cannot be produced by any classical geological process like regional metamorphism or magmatism. In consequence, impacts produce rocks called "impactites" that are very distinct from lithologies of continental or oceanic crust. Their composition varies between molten glass (tektites and spheruls), diaplectic glasses (amorphous phases), breccias with either entirely or partially glassy matrix, and rock fragments enclosed in a fine grained fragmental matrix. To determine an age, isotopic equilibrium must be achieved among the newly produced phases. Such conditions are potentially present in glasses that are produced by residual heat after decompression ( C). The best candidates on the large scale are: samples taken in melt layers of craters, in the glassy matrix of breccias in the crater area, as well as tektites and spheruls found in distant ejecta. The presence of such types of ejecta allows to date the impact event through the analyses of layers preserved in sediments. An excellent example for this scenario is the Cretaceous-Tertiary boundary where a large series of impact produced minerals have been preserved. In certain cases, it is possible to trace events even if the crater remains unknown. The majority of shock-wave produced rocks are not in isotopic equilibrium, and often the values measured represent mixed ages or disturbed systems, not giving the impact age. Only the combination of different dating methods, and very selective sample selection allows impact dating.
Sch�rer, Urs
Virtual courseware for geoscience education: Virtual Earthquake and Virtual Dating
NASA Astrophysics Data System (ADS)
Virtual courseware developed for introductory-level, on-line geology labs is an interactive teaching/learning model that has an enormous pedagogical potential for making Web sites places where students learn by doing. Virtual Earthquake and Virtual Dating are modest examples of the `virtual courseware' paradigm. Virtual Earthquake helps students explore the techniques of how an earthquake's epicenter is located and how its Richter magnitude is determined. Virtual Dating models the theory and techniques of the radiometric age determination of rocks and minerals. Virtual courseware applications offer several advantages over traditional floppy disk or CD ROM-based courseware, the most significant being the ease of dissemination. The author's experience with bringing these two virtual applications on-line suggests that there is a need for interactive geology labs on-line and that the approach will be received with enthusiasm by the educational community. The widespread implementation and adoption of virtual courseware can bring meaningful educational content and interactivity for the geosciences that goes beyond multimedia on the World-Wide-Web.
Novak, Gary A.
Application of a combination of dating techniques to reconstruct the Lateglacial and early Holocene landscape history of the Albula region (eastern Switzerland)
NASA Astrophysics Data System (ADS)
Landforms in Val Mulix and the Albula region in eastern Switzerland offer a detailed insight into the period between the Oldest Dryas until the early Holocene. To better understand Lateglacial and Holocene climate change in the central Alps, glacial (moraines, polished bedrock) and periglacial (rock glacier) landforms were dated using a combined approach of numerical (cosmogenic 10Be) and relative (Schmidt-hammer, weathering rind thickness) dating techniques. At high-elevation sites near the Last Glacial Maximum (LGM) trimline, 10Be exposure ages of glacially modified bedrock are between 11.2 ka and 13.5 ka. This suggests the persistence of long-lasting small local ice caps after the breakdown of the LGM ice domes or, alternatively, a reformation of ice perhaps during the Younger Dryas. In Val Mulix we obtained one of the first ages for the Daun-stadial (> 14.7 ka) moraines (14.9 � 1.8 ka), supporting a pre-B�lling chronological position. The age is in excellent agreement with the age of a boulder from an Egesen I moraine located up-valley which we postulate may be a Daun moraine that was re-occupied during the Egesen stadial. A boulder from an Egesen II moraine gave an age of 10.7 ka, which is similar to ages of Egesen II moraines at other sites in the Alps. 10Be ages from boulders found on a relict rock glacier in Val Mulix indicate that the main active phase lasted from the Lateglacial until the early Holocene. The derived mean annual flow rate is of the order of decimetres, which is in accordance with values stated in the literature based on measuring active rock glaciers in the Alps. Exposure ages from a glacially polished rock barrier showed that this area was ice-free at the end of the Younger Dryas (9.0 � 0.7 ka and 11.9 � 0.9 ka). The polished bedrocks are located a few hundred meters down-valley from the Little Ice Age (LIA) moraines. This gives direct evidence of a fast ice retreat towards the end of the Younger Dryas, with glacier length variations that did not exceed the 1850 AD extension (Little Ice Age maximum). Surface exposure dating is, however, limited by several methodological constraints. The choice of suitable snow depths plays a crucial role in the calculation of the 10Be ages. Shielding of surfaces from cosmic rays by snow can significantly influence the exposure age, and variations in the estimated annual snowfall in the Albula region since the LGM is therefore a potential source of considerable uncertainty in our measurements. While the measurement of weathering rind thicknesses turned out to be an appropriate tool to support the reconstruction of Lateglacial landscape evolution, Schmidt-hammer R-values were less helpful. The R-values enabled a temporal distinction of landforms within the Holocene (LIA moraine, active rock glaciers) but not within the Lateglacial. From a methodological point of view, the different dating methods enabled a cross-checking, an extended interpretation of the data and a more accurate estimate of the possible sources of error.
B�hlert, Ralph; Egli, Markus; Maisch, Max; Brandov�, Dagmar; Ivy-Ochs, Susan; Kubik, Peter W.; Haeberli, Wilfried
Airborne Radiometrics and Comparison with Activity Measurements in Groundwater
NASA Astrophysics Data System (ADS)
Airborne geophysical measurements including magnetics, electromagnetics and radiometry were carried out in a 312 sqkm large area in eastern Bavaria comprising crystalline rocks and Cenozoic sediments. The helicopter-borne investigations of 2007 were accompanied by ground-borne gamma spectroscopy and radon activity measurements in groundwater outcrops. The comparison of the radiometric data gathered allows to delineate hidden granitic intrusions and to distinguish between different intrusive phases of the igneous rocks suites. Furthermore fault systems can be mapped or proved and the depth of the weathering zone in hard rock areas can be roughly assessed in certain areas, both crucial for groundwater exploitation in hard rock environment. Besides that, hydrogeological implications from airborne data are scarce, due to the great heterogeneity of the geological background. Rn-222 activity measurements at springs using liquid scintillation counter (LSC) technique, however, proved to be a simple method to distinguish waters otherwise chemically indistinct. Even though not an intrinsic property of groundwater but a geological parameter measured in groundwater, radon measurements, especially multiple measurements and time series additionally may provide useful information for groundwater monitoring: Time dependent variations of radon concentrations can be correlated with fluctuations of areal precipitation and thus indicate the varying impact of surface run-off or shallow groundwater of superficial deposits. The basic difference in radiometric characteristics of groundwater and surface water can also be utilized in monitoring the hydrological regime (infiltration vs. exfiltration) within river valleys.
Diepolder, G. W.; Herold, H.; Siemon, B.
Principal Component Noise Filtering for NAST-I Radiometric Calibration
NASA Technical Reports Server (NTRS)
The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Testbed- Interferometer (NAST-I) instrument is a high-resolution scanning interferometer that measures emitted thermal radiation between 3.3 and 18 microns. The NAST-I radiometric calibration is achieved using internal blackbody calibration references at ambient and hot temperatures. In this paper, we introduce a refined calibration technique that utilizes a principal component (PC) noise filter to compensate for instrument distortions and artifacts, therefore, further improve the absolute radiometric calibration accuracy. To test the procedure and estimate the PC filter noise performance, we form dependent and independent test samples using odd and even sets of blackbody spectra. To determine the optimal number of eigenvectors, the PC filter algorithm is applied to both dependent and independent blackbody spectra with a varying number of eigenvectors. The optimal number of PCs is selected so that the total root-mean-square (RMS) error is minimized. To estimate the filter noise performance, we examine four different scenarios: apply PC filtering to both dependent and independent datasets, apply PC filtering to dependent calibration data only, apply PC filtering to independent data only, and no PC filters. The independent blackbody radiances are predicted for each case and comparisons are made. The results show significant reduction in noise in the final calibrated radiances with the implementation of the PC filtering algorithm.
Tian, Jialin; Smith, William L., Sr.
NASA IKONOS Multispectral Radiometric Calibration and 3-Year Temporal Stability Assessment
NASA Technical Reports Server (NTRS)
Radiometric calibration of commercial imaging satellite products is required to ensure that science and application communities can place confidence in the imagery they use and can fully understand its properties. Inaccurate radiometric calibrations can lead to erroneous decisions and invalid conclusions and can limit intercomparisons with other system. In addition, the user community has little or no insight into the design and operation of commercial sensors or into the methods involved in generating commercial products. To address this calibration need, the NASA Stennis Space Center (SSC) Earth Science Applications (ESA) Directorate established a commercial satellite imaging radiometric calibration team consisting of three independent groups: NASA, SSC,ESA, the University of Arizona Remote Sensing Group, and South Dacota State University. Each group determined the absolute radiometric calibration coefficients of the Space Imaging IKONOS 4-band, 4 m multispectral product covering the visible through near-infrared spectral region. For a three year period beginning in 2000, each team employed some variant of a reflectance-based vicarious calibration approach, requiring ground-based measurements coincident with IKONOS image acquisitions and radiative transfer calculations. Several study sites throughout the United States were employed that covered nearly the entire dynamic range of the IKONOS sensor. IKONOS at-sensor radiance values were compared to those estimated by each independent group to determine the IKONOS sensor's radiometric accuracy and stability. Over 10 individual vicariously determined at-sensor radiance estimates were used each year. When combined, these estimates provided a high-precision radiometric gain calibration coefficient. No significant calibration offset was observed. The results of this evaluation provide the scientific community with an independent assessment of the IKONOS sensor's absolute calibration and temporal stability over the 3-year period. While the techniques and method described in this paper reflect those developed at the NASA SSC, the results of the entire team are included.
Pagnutti, Mary; Carver, David; Holekamp, Kara; Ryan, Robert; Zanoni, Vicki; Thome, Kurtis; Schiller, Stephen; Aaran, David
Tongan pottery chronology, 14C dates and the hardwater effect
NASA Astrophysics Data System (ADS)
As with many other Pacific iarchaelogical sites, the chronology of the Lapita sites on Tongatapu (Tonga) rests on two bases: a seriation of form and ornament attributes of pottery, and the absolute chronology as determined by radiocarbon dates. Both systems were in disagreement, casting doubt on the reliability of the pottery seriation. The enclosed nature of the lagoon of Tongatapu, coupled with the dissolution of fossil limestone, creates a water reservoir with an apparent age greater than the apparent age of that provided by the open ocean. A lagoon-specific reservoir correction factor was measured using pre-modern reference shells with known dates of collection. When the radiometric dates are corrected using this factor, both chronologies, pottery seriation and radiometric dates, are in perfect agreement. The paper demonstrates how micro-reservoirs impact on ages derived from 14C determinations and shows the need to determine the magnitude of localised variations in 14C.
Spennemann, Dirk H. R.; John Head, M.
Mass spectrometric 3He measurement in 4He-rich phases: Techniques and limitations for cosmogenic 3He dating of zircon, apatite, and titanite
NASA Astrophysics Data System (ADS)
Recent calibration studies have expanded the range of target minerals suitable for cosmogenic 3He dating to include U and Th-rich phases such as zircon, apatite, and titanite. These minerals often contain large amounts of radiogenic 4He that present several analytical challenges for precise and accurate 3He determinations. In this paper we document the abundance sensitivity and changes in the absolute sensitivity and time evolution of the 3He signal over a wide range of 4He pressures in a MAP 215-50 noble gas mass spectrometer. Large (>50%) decreases in sensitivity with 4He amount arising from space charge effects were observed but can be corrected for using an isotope dilution-like technique in which 3He spike is added to a sample midway through the mass spectrometric analysis. Large amounts of 4He also cause the time evolution of the 3He signal to become steeper, degrading precision of the initial peak height determination from the intercept. Taken together we find that these effects preclude reliable analysis of samples with 4He > 1 ?mol and that 3He/4He ratios of greater than �5 � 10-10 are required to routinely measure 3He to better than 20% precision. We present some general considerations by which to assess the probability of success of measuring cosmogenic 3He in these phases as a function of elevation, exposure age, and helium cooling age.
Amidon, William H.; Farley, Kenneth A.
Oxygen isotope studies and compilation of isotopic dates from Antarctica
The Quaternary Isotope Laboratory, alone or in collaboration with other investigators, is currently involved in a number of oxygen-isotope studies mainly in Antarctica. Studies of a drill core from the South Pole, seasonal oxygen-18 signals preserved in the Dominion Range, isotope dating of the Ross Ice Shelf, oxygen-18 profiles of the Siple Coast, McMurdo Ice Shelf sampling, and a data compilation of radiometric dates from Antarctica are discussed.
Grootes, P.M.; Stuiver, M.
NASA Technical Reports Server (NTRS)
[figure removed for brevity, see original site]This VIS image of the eastern part of the Tharsis region illustrates how fractures can be used in relative dating of a surface. The fractured materials on the right side of the image are embayed by younger volcanic flows originating to the west of the image. Note how the younger flows cover the ends of the fractures, and are not at all fractured themselves. Image information: VIS instrument. Latitude 43.2, Longitude 269.4 East (90.6 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.
Revised landsat-5 thematic mapper radiometric calibration
Effective April 2, 2007, the radiometric calibration of Landsat-5 (L5) Thematic Mapper (TM) data that are processed and distributed by the U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science (EROS) will be updated. The lifetime gain model that was implemented on May 5, 2003, for the reflective bands (1-5, 7) will be replaced by a new lifetime radiometric-calibration curve that is derived from the instrument's response to pseudoinvariant desert sites and from cross calibration with the Landsat-7 (L7) Enhanced TM Plus (ETM+). Although this calibration update applies to all archived and future L5 TM data, the principal improvements in the calibration are for the data acquired during the first eight years of the mission (1984-1991), where the changes in the instrument-gain values are as much as 15%. The radiometric scaling coefficients for bands 1 and 2 for approximately the first eight years of the mission have also been changed. Users will need to apply these new coefficients to convert the calibrated data product digital numbers to radiance. The scaling coefficients for the other bands have not changed. ?? 2007 IEEE.
Chander, G.; Markham, B. L.; Barsi, J. A.
Radiometric calibration of Advanced Land Imager using reflectance-based results between 2001 and 2005
NASA Astrophysics Data System (ADS)
The Landsat series of sensors have supplied the remote sensing community with a continuous data set dating to the early 1970s. An important aspect of retaining the continuity of these data is that a Landsat follow-on as well as current Landsat instruments must be understood radiometrically throughout their mission. The Advanced Land Imager (ALI), for example, was developed as a prototype for the next generation of Landsat Instruments, and as such there was a significant effort to understand its radiometric characteristics as well as how it compares with previous Landsat sensors. The Remote Sensing Group at the University of Arizona has been part of this effort since the late 2000 launch of ALI through the use of the reflectance-based method of vicarious calibration. The reflectance-based approach consists of ground-based measurements of atmospheric conditions and surface reflectance at the time of satellite overpass to predict the at-sensor radiance seen by the sensor under study. The work compares results from the reflectance-based approach obtained from well-characterized test sites such as Railroad Valley Playa in Nevada and Ivanpah Playa in California as applied to ALI, Landsat-5 TM, and Landsat-7 EMT+. The results from the comparison use a total of 14 ALI dates spanning in time from 2001 to late 2005 and show that ALI agrees with the current radiometric results from TM and ETM+ to within 5%.
McCorkel, J.; Thome, K.; Biggar, S.; Kuester, M.
Dating terrestrial impact events
NASA Astrophysics Data System (ADS)
Systematic examination of dating results from various craters indicates that about 90% of the rocks affected by an impact preserve their pre-shock ages because shock and post-shock conditions are not sufficient to disturb isotopic dating systems. In the other 10% of target lithologies, various geochronometers show significant shock-induced effects. Major problems in dating impactites are caused by their non-equlibrated character. They often display complex textures, where differently shocked and unshocked phases interfinger on the sub-mm scale. Due to this, dating on whole rock samples or insufficiently pure mineral fractions often yielded ambiguous results that set broad age limits but are not sufficient to answer reliably questions such as a possible periodicity in cratering on Earth, or correlation of impact events with mass extinctions. Dating results from shock recovery experiments indicate that post-shock annealing plays the most important role in resetting isotopic clocks. Therefore, the major criterion for sample selection in and around craters is the post-shock thermal regime. Based on their different thermal evolution, the following geological impact formations can be distinguished: (1) the coherent impact melt layer, (2) allochthonous breccia deposits, (3) the crater basement, and (4) distant ejecta deposits. Samples of the coherent impact melt layer are the most suitable candidates for dating. Excellent ages of high precision can be obtained by internal Rb-Sr, and Sm-Nd isochrons, U-Pb analyses on newly crystallized accessory minerals, and K-Ar (Ar-39-Ar-40) dating of clast-free melt rocks. Fission track counting on glassy material has yielded correct ages, and paleomagnetic measurements have been successfully applied to post-Triassic craters. In the ideal case of a fast-cooling impact melt layer, all these different techniques should give identical ages. Allochthonous breccias contain shocked, unshocked, and/or glassy components in various proportions; and, hence, each of these ejecta deposits has its own individual thermal history, making sample evaluation difficult. Glassy melt particles in suevitic breccias are well suited for fission track and Ar-Ar dating. Weakly shocked material may yield reliable Ar-Ar and fission track ages, if formation temperatures were high, and cooling rates moderate. In contrast, highly shocked but rapidly cooled lithologies show only disturbed and not reset isotopic systems. For ejecta deposits and the crater wall of young craters, dating with cosmogenic nuclides is a new and powerful technique. Crater basement lithologies have a high potential in impact dating, although it has not been exploited so far. techniques are most promising, because both systems are easily reset at low temperatures. Good candidates for impact dating are long-term annealed rocks, even if shock metamorphic overprint is very weak. In addition, Ar-Ar dating dating of pseudotachylites appears promising. *In large impact structures, where high temperatures persist for long times, polymict 'footwall' breccias beneath the melt sheet are also appropriate for dating, using the isochron approach and U-Pb on accessory minerals. -Distant ejecta material have undergone very fast cooling, and the ejecta deposits have ambient formation temperatures. Among this material, tektites and impact melt glass are ideal objects for Ar-Ar and fission track impact dating. Dating on other material from distant ejecta deposits, such as U-Pb analyses on zircons, offers new possibilities. %Efforts to correlate distant ejecta with distinct craters critically depend on proper error assignment to a specific age. This aspect is illustrated on the K/T boundary example.
Deutsch, Alexander; Schaerer, Urs
Laser Pulse Variations and Their Influence on Radiometric Calibration of Full-Waveform Laser Scanner Data
NASA Astrophysics Data System (ADS)
Full-waveform laser scanning extends the information content of "conventional" laser scanning by storing the temporal pro?le of both the emitted laser pulse and its echoes. This allows for calculating radiometric quantities in addition to the geometric data. This radio- metric information needs to be calibrated in order to enable comparison among ?ight strips of the same laser scanner campaign and/or different campaigns. Radiometric calibration is aimed at the determination of a calibration constant which contains the parameters of the emitted laser pulse (besides others). All of these parameters are normally treated as constants. In this paper, the sensitivity of the calibration constant to variations of the emitted laser pulse is analysed theoretically by deriving it according to the error propagation law, followed by an empirical analysis carried out on the example of two airborne full-waveform laser scanning campaigns. Both were operated with the same instrument and over the same area on two different dates.
Roncat, A.; Lehner, H.; Briese, C.
This preliminary report examines those radiometric characteristics of the Landsat 4 Thematic Mapper (TM) that can be established without absolute calibration of spectral data. Analysis is based largely on radiometrically raw (B type) data of three daytime and two nighttime scenes; in most scenes, a set of 512 lines were examined on an individual-detector basis. Subscenes selected for uniform-radiance were used to characterize subtle radiometric differences and noise problems.
Kieffer, Hugh, H.; Eliason, Eric, M.; Chavez, Jr. , Pat, S.
Radiometric cloud imaging with an uncooled microbolometer thermal infrared camera
An uncooled microbolometer-array thermal infrared camera has been incorporated into a remote sensing system for radiometric sky imaging. The radiometric calibration is validated and improved through direct comparison with spectrally integrated data from the Atmospheric Emitted Radiance Interferometer (AERI). With the improved calibration, the Infrared Cloud Imager (ICI) system routinely obtains sky images with radiometric uncertainty less than 0.5 W\\/(m2
Joseph A. Shaw; Paul W. Nugent; Nathan J. Pust; Brentha Thurairajah; Kohei Mizutani
Relative radiometric calibration of LANDSAT TM reflective bands
NASA Technical Reports Server (NTRS)
Raw thematic mapper (TM) calibration data from pre-launch tests and in-orbit acquisitions from LANDSAT 4 and 5 satellites are analyzed to assess the radiometric characteristics of the TM sensor. A software program called TM radiometric and algorithmic performance program (TRAPP) was used for the majority of analyses. Radiometric uncertainty in the final TM image originates from: (1) scene variability (solar irradiance and atmospheric scattering); (2) optical and electrical variability of the sensor; and (3) variability introduced during image processing.
Barker, J. L.
NASA Technical Reports Server (NTRS)
A large and diverse number of computational techniques are routinely used to process and analyze remotely sensed data. These techniques include: univariate statistics; multivariate statistics; principal component analysis; pattern recognition and classification; other multivariate techniques; geometric correction; registration and resampling; radiometric correction; enhancement; restoration; Fourier analysis; and filtering. Each of these techniques will be considered, in order.
Park, Steve
Radiometric calibration for MWIR cameras
NASA Astrophysics Data System (ADS)
Korean Multi-purpose Satellite-3A (KOMPSAT-3A), which weighing about 1,000 kg is scheduled to be launched in 2013 and will be located at a sun-synchronous orbit (SSO) of 530 km in altitude. This is Korea's rst satellite to orbit with a mid-wave infrared (MWIR) image sensor, which is currently being developed at Korea Aerospace Research Institute (KARI). The missions envisioned include forest re surveillance, measurement of the ocean surface temperature, national defense and crop harvest estimate. In this paper, we shall explain the MWIR scene generation software and atmospheric compensation techniques for the infrared (IR) camera that we are currently developing. The MWIR scene generation software we have developed taking into account sky thermal emission, path emission, target emission, sky solar scattering and ground re ection based on MODTRAN data. Here, this software will be used for generating the radiation image in the satellite camera which requires an atmospheric compensation algorithm and the validation of the accuracy of the temperature which is obtained in our result. Image visibility restoration algorithm is a method for removing the eect of atmosphere between the camera and an object. This algorithm works between the satellite and the Earth, to predict object temperature noised with the Earth's atmosphere and solar radiation. Commonly, to compensate for the atmospheric eect, some softwares like MODTRAN is used for modeling the atmosphere. Our algorithm doesn't require an additional software to obtain the surface temperature. However, it needs to adjust visibility restoration parameters and the precision of the result still should be studied.
Yang, Hyunjin; Chun, Joohwan; Seo, Doo Chun; Yang, Jiyeon
Dating the demise: Neandertal extinction and the establishment of modern humans in the southern Caucasus
This paper considers the recent radiometric dating (14C-AMS, TL, ESR) of 76 late Middle and early Upper Paleolithic samples from Ortvale Klde Rockshelter, located in the Republic of Georgia. We present a critical evaluation of each date based on its stratigraphic and archaeological context, its pretreatment and contamination history, and its resulting accuracy and precision, the goal being to establish
Daniel S. Adler; Ofer Bar-Yosef; Anna Belfer-Cohen; Nicholas Tushabramishvili; E. Boaretto; N. Mercier; H. Valladas; W. J. Rink
Dating of Submarine Landslides and Their Tsunami Deposits Using Hawaii as an Example
There have been several approaches to dating the initiation of submarine landslides and the tsunamis they inevitably produce. In Hawaii, the timing of flank failures of major volcanoes has been estimated by radiometric and paleomagnetic dating of the youngest shield-building flows and dikes, the apex ages of the volcanoes, which can also be constrained by the oldest flows of post-collapse
G. M. McMurtry; E. Herrero-Bervera
Earthtime Lesson Plan for U/Pb Dating (grade 8-12)
NSDL National Science Digital Library
The Earthtime Lesson Plan is a complete description of a radiometric dating module taught to high school students at MIT. U/Pd dating and it's uses, teacher background, materials needed, time frame and National Science Standards are all provided as well as worksheets with teacher solutions. This module, consisting of three activities, is initially designed for a 90min period.
U�Pb dating of detrital zircons for sediment provenance studies�a comparison of laser ablation ICPMS and SIMS techniques
New developments in U�Pb dating of zircons by laser ablation (LA) ICPMS are described and, for the first time, a direct comparison of detrital zircons dated by LA ICPMS and SIMS methods is presented. True real-time mass bias correction is made by aspirating a Tl\\/U tracer at the same time as laser ablation. The method is similar to that described
Jan Ko�ler; Hege Fonneland; Paul Sylvester; Mike Tubrett; Rolf-Birger Pedersen
The Schmidt hammer as a Holocene calibrated-age dating technique: Testing the form of the R-value-age relationship and defining the predicted-age errors
Most recent developments of Schmidt-hammer exposure-age dating (SHD) as a calibrated-age dating tool have been limited by the use of locations at two age control points. This has necessitated: (1) making assumptions about a linear R-value�age relationship; and (2) basing predictions of age errors only on R-value variance at the two age control points. This paper analyses 9900 R-values obtained
Richard A. Shakesby; John A. Matthews; Wibj�rn Karl�n; Sietse O. Los
Relative Dating in Archaeology
NSDL National Science Digital Library
These two classroom exercises introduce students to stratigraphy and the law of superposition as well as seriation, dating techniques used by archaeologists to establish a relative chronology. They can be adapted to students at different levels using local materials. In the first exercise, dated materials such as newspapers may be used to illustrate the concepts; students may then manipulate materials to simulate mapping and excavation or create a poster. In the second exercise, students are shown and discuss materials to develop their understanding of artifacts and materials within the context of a culture.
Griggs, Cathy
Relative Dating in Archaeology
NSDL National Science Digital Library
These two classroom exercises introduce students to stratigraphy and the law of superposition as well as seriation, dating techniques used by archaeologists to establish a relative chronology. They can be adapted to students at different levels using local materials. In the first exercise, dated materials such as newspapers may be used to illustrate the concepts; students may then manipulate materials to simulate mapping and excavation or create a poster. In the second exercise, students are shown and discuss materials to develop their understanding of artifacts and materials within the context of a culture.
Griggs, Cathy
Optical Imaging and Radiometric Modeling and Simulation
NASA Technical Reports Server (NTRS)
OPTOOL software is a general-purpose optical systems analysis tool that was developed to offer a solution to problems associated with computational programs written for the James Webb Space Telescope optical system. It integrates existing routines into coherent processes, and provides a structure with reusable capabilities that allow additional processes to be quickly developed and integrated. It has an extensive graphical user interface, which makes the tool more intuitive and friendly. OPTOOL is implemented using MATLAB with a Fourier optics-based approach for point spread function (PSF) calculations. It features parametric and Monte Carlo simulation capabilities, and uses a direct integration calculation to permit high spatial sampling of the PSF. Exit pupil optical path difference (OPD) maps can be generated using combinations of Zernike polynomials or shaped power spectral densities. The graphical user interface allows rapid creation of arbitrary pupil geometries, and entry of all other modeling parameters to support basic imaging and radiometric analyses. OPTOOL provides the capability to generate wavefront-error (WFE) maps for arbitrary grid sizes. These maps are 2D arrays containing digital sampled versions of functions ranging from Zernike polynomials to combination of sinusoidal wave functions in 2D, to functions generated from a spatial frequency power spectral distribution (PSD). It also can generate optical transfer functions (OTFs), which are incorporated into the PSF calculation. The user can specify radiometrics for the target and sky background, and key performance parameters for the instrument s focal plane array (FPA). This radiometric and detector model setup is fairly extensive, and includes parameters such as zodiacal background, thermal emission noise, read noise, and dark current. The setup also includes target spectral energy distribution as a function of wavelength for polychromatic sources, detector pixel size, and the FPA s charge diffusion modulation transfer function (MTF).
Ha, Kong Q.; Fitzmaurice, Michael W.; Moiser, Gary E.; Howard, Joseph M.; Le, Chi M.
Airborne SAR radiometric calibration using point targets
NASA Astrophysics Data System (ADS)
The trihedral corner reflector, with high stability, large RCS and little change within a wide angle range, is widely used in SAR radiometric calibration. Results from airborne SAR overflights of corner reflectors are utilized to compute calibration constant, transfer function of the system and backscattering coefficient of different targets. The key step of SAR calibration is the derivation of calibration constant. In this paper, we used two methods, the peak and integral method, to compute the calibration constant. Through real flight data, we found that, using point target for SAR calibration is simple and practicable.
Zongmin, Feng; Lei, Huang; Zhihua, Tang; Jiuli, Liu; Liangbo, Zhao
Thermochronology of economic mineral deposits: dating the stages of mineralization at Panasqueira, Portugal, by high-precision 40Ar/ 39Ar age spectrum techniques on muscovite
This study is an example of a new and powerful application of 40Ar/39Ar age spectrum dating of muscovite. It is now possible to establish time constraints necessary for solving some of the long-standing problems in economic geology. Beyond this, the unique geologic situation of Panasqueira has allowed us to quantify the thermal characteristics of muscovite. Published fluid inclusion data have been used to estimate a muscovite argon closure temperature of ~325??C during rapid cooling or short reheating and a temperature of ~270??C during slow cooling or extended reheating. Argon-loss patterns displayed by all dated muscovites resulted from reheating after original closure; the mechanism for this argon loss appears to have been argon transport by volume diffusion. Thus, 40Ar/39Ar age spectrum dating of muscovite can be used to evaluate thermal conditions controlling argon diffusion as well as age, duration, and number of episodes of mineralization. -from Authors
Snee, L. W.; Sutter, J. F.; Kelly, W. C.
Development of an emissivity compensation algorithm for radiometric temperature measurement during the galvanneal process
During the galvanneal process, zinc-coated steel sheet is rapidly annealed in order to improve the characteristics of the final product. The zinc layer changes from highly specular liquid zinc with a spectral emissivity of approximately 0.2 to a largely diffuse intermetallic layer with a spectral emissivity as high as 0.8. These rapid emissivity changes preclude standard radiometric measurement techniques. The
Lynn Krajnovich Zentner
A radiometric airborne geophysical survey of the Isle of Wight
A high resolution airborne geophysical survey across the Isle of Wight and Lymington area conducted in 2008 provided the first modern radiometric survey across the geological formations that characterise much of southern England. The basic radiometric data are presented and it is evident that bedrock geology exerts a controlling influence on the broad response characteristics of the naturally occurring radioelements.
David Beamish; James C. White
A multichannel radiometric profiler of temperature, humidity, and cloud liquid
A microwave radiometer is described that provides continuous thermodynamic (temperature, water vapor, and moisture) soundings during clear and cloudy conditions. The radiometric profiler observes radiation intensity at 12 microwave frequencies, along with zenith infrared and surface meteorological measurements. Historical radiosonde and neural network or regression methods are used for profile retrieval. We compare radiometric, radiosonde, and forecast soundings and evaluate
Randolph Ware; Richard Carpenter; J�rgen G�ldner; James Liljegren; Thomas Nehrkorn; Fredrick Solheim; Francois Vandenberghe
Relative radiometric calibration of LANDSAT TM reflective bands
NASA Technical Reports Server (NTRS)
A common scientific methodology and terminology is outlined for characterizing the radiometry of both TM sensors. The magnitude of the most significant sources of radiometric variability are discussed and methods are recommended for achieving the exceptional potential inherent in the radiometric precision and accuracy of the TM sensors.
Barker, J. L.
Relative Radiometric Normalization and Atmospheric Correction of a SPOT 5 Time Series
Multi-temporal images acquired at high spatial and temporal resolution are an important tool for detecting change and analyzing trends, especially in agricultural applications. However, to insure a reliable use of this kind of data, a rigorous radiometric normalization step is required. Normalization can be addressed by performing an atmospheric correction of each image in the time series. The main problem is the difficulty of obtaining an atmospheric characterization at a given acquisition date. In this paper, we investigate whether relative radiometric normalization can substitute for atmospheric correction. We develop an automatic method for relative radiometric normalization based on calculating linear regressions between unnormalized and reference images. Regressions are obtained using the reflectances of automatically selected invariant targets. We compare this method with an atmospheric correction method that uses the 6S model. The performances of both methods are compared using 18 images from of a SPOT 5 time series acquired over Reunion Island. Results obtained for a set of manually selected invariant targets show excellent agreement between the two methods in all spectral bands: values of the coefficient of determination (r2 exceed 0.960, and bias magnitude values are less than 2.65. There is also a strong correlation between normalized NDVI values of sugarcane fields (r2 = 0.959). Despite a relative error of 12.66% between values, very comparable NDVI patterns are observed.
Hajj, Mahmoud El; Begue, Agnes; Lafrance, Bruno; Hagolle, Olivier; Dedieu, Gerard; Rumeau, Matthieu
Luminescence dating of last interglacial coastal deposits of Cyprus: overcoming quartz complications by elevated-temperature Infrared Stimulated Luminescence (IRSL) from feldspars.
NASA Astrophysics Data System (ADS)
When dating samples from a coastal area of South East Cyprus it was revealed that the OSL characteristics of quartz were problematic giving highly scattered and unexpectedly low Des. Deconvolution of the CW-OSL signals showed that the most likely cause for these underestimations was due to a weak fast component, accompanied by a thermally unstable medium component. Fortunately, recent advancements in luminescence dating have made possible the use of feldspar IRSL instead. Particularly, the "post-infrared infrared stimulated luminescence", known as p-IRIR not only compensates for the problems associated with quartz but also saves all benefits of feldspar dating, such as intense signals under laboratory stimulation and considerably higher saturation levels, and additionally deals with the problem of anomalous fading. The potential application of an elevated temperature p-IRIR SAR protocol developed by Thiel et al. (2011) for feldspar is examined for seven late Pleistocene coastal aeolian and littoral samples from a coastal site in south east Cyprus. Published radiometric ages from the same site put additional significance on evaluating the effectiveness of p-IRIR dating, as independent age control on the latter remains scarce in literature to date. Indeed, p-IRIR and published radiometric ages for Cyprus are in a good agreement. Ages are in stratigraphic order assigning the formation of the studied deposits to the Last Interglacial stage. The p-IRIR dating was concluded to be a reliable technique for establishing precise and accurate chronologies and a trustworthy alternative to quartz optically stimulated luminescence (OSL) dating when the quartz luminescence characteristics are unsuitable.
Tsakalos, Evangelos; Athanassas, Constantin; Bassiakos, Yannis
Evaluating radiometric consistency between Suomi NPP VIIRS and NOAA-19 AVHRR using extended simultaneous nadir overpass in the low latitudes
NASA Astrophysics Data System (ADS)
The Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi NPP has been undergoing extensive calibration/validation efforts in order to produce high quality weather and climate quality satellite data products. VIIRS absolute radiometric accuracy and consistency can be achieved by inter-comparing its measurements with other well calibrated instruments such as AQUA MODIS. VIIRS moderate resolution bands compared with matching MODIS bands at North African desert has shown that that the radiometric bias for channels M-1 through M-8 is less than 2%. VIIRS is a follow on mission for MODIS and AVHRR. In an effort to evaluate radiometric consistency of VIIRS with multi-decadal global earth observations from AVHRR, this study uses SNO-x approach to inter-compare NOAA-19 AVHRR measurements with VIIRS at North African desert over VNIR region. The radiometric consistency is evaluated and the uncertainty due to spectral differences is quantified using hyperspectral measurements from EO-1 Hyperion. In addition, the Antarctica Dome C site is used to estimate radiometric bias between AVHRR and VIIRS. AVHRR bias relative to VIIRS at Dome C is well within 0.5% for band 1 and 2% for band 2 compared to bias estimated at the desert sites using the SNO-x technique.
Uprety, Sirish; Cao, Changyong; Blonski, Slawomir; Shao, Xi
Visible/infrared radiometric calibration station
We have begun construction of a visible/infrared radiometric calibration station that will allow for absolute calibration of optical and IR remote sensing instruments with clear apertures less than 16 inches in diameter in a vacuum environment. The calibration station broadband sources will be calibrated at the National Institute of Standards and Technology (NIST) and allow for traceable absolute radiometric calibration to within {plus_minus}3% in the visible and near IR (0.4--2.5 {mu}m), and less than {plus_minus}1% in the infrared, up to 12 {mu}m. Capabilities for placing diffraction limited images or for sensor full-field flooding will exist. The facility will also include the calibration of polarization and spectral effects, spatial resolution, field of view performance, and wavefront characterization. The configuration of the vacuum calibration station consists of an off-axis 21 inch, f/3.2, parabolic collimator with a scanning fold flat in collimated space. The sources are placed, via mechanisms to be described, at the focal plane of the off-axis parabola. Vacuum system pressure will be in the 10{sup {minus}6} Torr range. The broadband white-light source is a custom design by LANL with guidance from Labsphere Inc. The continuous operating radiance of the integrating sphere will be from 0.0--0.006 W/cm{sup 2}/Sr/{mu}m (upper level quoted for {approximately}500 nm wavelength). The blackbody source is also custom designed at LANL with guidance from NIST. The blackbody temperature will be controllable between 250--350{degrees}K. Both of the above sources have 4.1 inch apertures with estimated radiometric instability at less than 1%. The designs of each of these units will be described. The monochromator and interferometer light sources are outside the vacuum, but all optical relay and beam shaping optics are enclosed within the vacuum calibration station. These sources are described, as well as the methodology for alignment and characterization.
Byrd, D.A.; Maier, W.B. II; Bender, S.C.; Holland, R.F.; Michaud, F.D.; Luettgen, A.L.; Christensen, R.W. [Los Alamos National Lab., NM (United States); O`Brian, T.R. [National Inst. of Standards and Technology (NML), Gaithersburg, MD (United States). Radiometric Physics Div.
Data from radar images integrated with information from traditional lithologic and dating techniques improve resolution of surficial geologic units in the central Florida peninsula
Side Looking Airborne Radar (SLAR) images provide information useful to 1:100,000-scale surficial geologic mapping across the Florida peninsula from Sarasota to Fort Pierce. The SLAR images show textural patterns, sharp gradients, and certain compositional variations that cause differences in reflectivity. Quaternary and Pliocene beach ridges and marginal marine plains, visible on SLAR images, occupy most of the eastern half of the area; the most prominent beach ridge, which was deposited during the late Pliocene or early Pleistocene, is the southern terminus of the central highlands of Florida. Other geologic features detected by radar are a change from iron-poor to moderately iron-rich soil that marks the boundary between two middle Quaternary ( ) units, oyster reefs associated with late Pleistocene bay deposits northwest of Lake Okeechobee, and permanent and ephemeral ponds that reflect the thickness of unconsolidated sediment over weathered carbonate rocks. In addition to the geomorphic and compositional information from SLAR, mineralogic, textural, and age data from drill holes and pits were used to delineate surficial geologic map units. Stratigraphic and numerical age estimates are based on molluscan biostratigraphy, uranium disequilibrium series dates on corals, [sup 87]Sr/[sup 66]Sr dates on molluscs, and [sup 14]C dates on peat and humate.
McCartan, L.; Moy, W.S.; Wingard, G.L. Owens, J.P.; Kover, A.N.; Van Valkenburg, S.G.; Mason, D.B. (Geological Survey, Reston, VA (United States))
Landsat-7 EMT+ On-Orbit Radiometric Calibration
NASA Technical Reports Server (NTRS)
Landsat-7 was launched on April 15, 1999 and completed its on orbit initialization and verification period on June 28, 1999. The ETM+ payload is similar to the TM sensors on previous Landsat satellites and incorporates two new devices to improve its absolute radiometric calibration. The Full Aperture Solar Calibrator (FASC) is a deployable diffuser panel. This device has been deployed 9 times to date, with a normal deployment schedule of once per month. The initial analysis of the FASC data has given absolute calibration results within 5% of the prelaunch integrating sphere calibrations and a range of variation of 2% between dates. The Partial Aperture Solar Calibrator (PASC), is a set of auxiliary optics that allows the ETM+ to view the sun through a reduced aperture. Data have normally been acquired on a daily basis with the PASC. Initial results with the PASC were encouraging, despite some unexpected saturation in the shortest wavelength band. The response of the ETM+ short wavelength (silicon) bands to the PASC increased initially and has begun to decrease in some of these bands. The longer wavelength (InSb) bands have shown up to 30% oscillations that vary between detectors within the band. Studies are ongoing to better characterize the response to the PASC. The ETM+ also incorporates an internal calibrator (IC), a shutter that oscillates in front of the focal plane that directs light from the internal calibrator lamps to the focal plane. The responses to this device are also varying, though differently than the PASC results. Both the IC and PASC results are attributable to the calibration devices as opposed to the ETM+ itself.
Markham, Brian L.; Barker, J. L.; Kaita, E.; Seiferth, J.; Morfitt, Ron
Radiometric responsivity determination for Feature Identification and Location Experiment (FILE) flown on space shuttle mission
NASA Technical Reports Server (NTRS)
A procedure was developed to obtain the radiometric (radiance) responsivity of the Feature Identification and Local Experiment (FILE) instrument in preparation for its flight on Space Shuttle Mission 41-G (November 1984). This instrument was designed to obtain Earth feature radiance data in spectral bands centered at 0.65 and 0.85 microns, along with corroborative color and color-infrared photographs, and to collect data to evaluate a technique for in-orbit autonomous classification of the Earth's primary features. The calibration process incorporated both solar radiance measurements and radiative transfer model predictions in estimating expected radiance inputs to the FILE on the Shuttle. The measured data are compared with the model predictions, and the differences observed are discussed. Application of the calibration procedure to the FILE over an 18-month period indicated a constant responsivity characteristic. This report documents the calibration procedure and the associated radiometric measurements and predictions that were part of the instrument preparation for flight.
Wilson, R. G.; Davis, R. E.; Wright, R. E., Jr.; Sivertson, W. E., Jr.; Bullock, G. F.
GIFTS SM EDU Radiometric and Spectral Calibrations
NASA Technical Reports Server (NTRS)
The Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) Sensor Module (SM) Engineering Demonstration Unit (EDU) is a high resolution spectral imager designed to measure infrared (IR) radiance using a Fourier transform spectrometer (FTS). The GIFTS instrument gathers measurements across the long-wave IR (LWIR), short/mid-wave IR (SMWIR), and visible spectral bands. The raw interferogram measurements are radiometrically and spectrally calibrated to produce radiance spectra, which are further processed to obtain atmospheric profiles via retrieval algorithms. This paper describes the processing algorithms involved in the calibration. The calibration procedures can be subdivided into three categories: the pre-calibration stage, the calibration stage, and finally, the post-calibration stage. Detailed derivations for each stage are presented in this paper.
Tian, J.; Reisse, R. a.; Johnson, D. G.; Gazarik, J. J.
Absolute radiometric calibration of the Thematic Mapper
NASA Technical Reports Server (NTRS)
Calibration data for the solar reflective bands of the Landsat-5 TM obtained from five in-flight absolute radiometric calibrations from July 1984-November 1985 at White Sands, New Mexico are presented and analyzed. Ground reflectance and atmospheric data were utilized to predict the spectral radiance at the entrance pupil of the TM and the average number of digital counts in each TM band. The calibration of each of the TM solar reflective bands was calculated in terms of average digital counts/unit spectral radiance for each band. It is observed that for the 12 reflectance-based measurements the rms variation from the means as a percentage of the mean is + or - 1.9 percent; for the 11 measurements in the IR bands, it is + or - 3.4 percent; and the rms variation for all 23 measurements is + or - 2.8 percent.
Slater, P. N.; Biggar, S. F.; Holm, R. G.; Jackson, R. D.; Mao, Y.
Absolute Radiometric Calibration of EUNIS-06
NASA Technical Reports Server (NTRS)
The Extreme-Ultraviolet Normal-Incidence Spectrometer (EUNIS) is a soundingrocket payload that obtains imaged high-resolution spectra of individual solar features, providing information about the Sun's corona and upper transition region. Shortly after its successful initial flight last year, a complete end-to-end calibration was carried out to determine the instrument's absolute radiometric response over its Longwave bandpass of 300 - 370A. The measurements were done at the Rutherford-Appleton Laboratory (RAL) in England, using the same vacuum facility and EUV radiation source used in the pre-flight calibrations of both SOHO/CDS and Hinode/EIS, as well as in three post-flight calibrations of our SERTS sounding rocket payload, the precursor to EUNIS. The unique radiation source provided by the Physikalisch-Technische Bundesanstalt (PTB) had been calibrated to an absolute accuracy of 7% (l-sigma) at 12 wavelengths covering our bandpass directly against the Berlin electron storage ring BESSY, which is itself a primary radiometric source standard. Scans of the EUNIS aperture were made to determine the instrument's absolute spectral sensitivity to +- 25%, considering all sources of error, and demonstrate that EUNIS-06 was the most sensitive solar E W spectrometer yet flown. The results will be matched against prior calibrations which relied on combining measurements of individual optical components, and on comparisons with theoretically predicted 'insensitive' line ratios. Coordinated observations were made during the EUNIS-06 flight by SOHO/CDS and EIT that will allow re-calibrations of those instruments as well. In addition, future EUNIS flights will provide similar calibration updates for TRACE, Hinode/EIS, and STEREO/SECCHI/EUVI.
Thomas, R. J.; Rabin, D. M.; Kent, B. J.; Paustian, W.
Precision radiometric surface temperature (PRST) sensor
NASA Astrophysics Data System (ADS)
There is a need for a Precision Radiometric Surface Temperature (PRST) measurement capability that can achieve noncontact profiling of a sample's surface temperature when heated dynamically during laser processing, aerothermal heating or metal cutting/machining. Target surface temperature maps within and near the heated spot provide critical quantitative diagnostic data for laser-target coupling effectiveness and laser damage assessment. In the case of metal cutting, this type of measurement provides information on plastic deformation in the primary shear zone where the cutting tool is in contact with the workpiece. The challenge in these cases is to measure the temperature of a target while its surface's temperature and emissivity are changing rapidly and with incomplete knowledge of how the emissivity and surface texture (scattering) changes with temperature. Bodkin Design and Engineering, LLC (BDandE), with partners Spectral Sciences, Inc. (SSI) and Space Computer Corporation (SCC), has developed a PRST Sensor that is based on a hyperspectral MWIR imager spanning the wavelength range 2-5 ?m and providing a hyperspectral datacube of 20-24 wavelengths at 60 Hz frame rate or faster. This imager is integrated with software and algorithms to extract surface temperature from radiometric measurements over the range from ambient to 2000K with a precision of 20K, even without a priori knowledge of the target's emissivity and even as the target emissivity may be changing with time and temperature. In this paper, we will present a description of the PRST system as well as laser heating test results which show the PRST system mapping target surface temperatures in the range 600-2600K on a variety of materials.
Daly, James T.; Roberts, Carson; Bodkin, Andrew; Sundberg, Robert; Beaven, Scott; Weinheimer, Jeffrey
Radiometric Detection of Some Food-Borne Bacteria
Studies on detection of bacteria by radiometric techniques have been concerned primarily with aerobic species in clinical specimens. The data presented here are related to detection of aerobic and anaerobic species that are of significance in foods, by measurement of 14CO2 evolved from the metabolism of 14C-glucose. Salmonella typhimurium and Staphylococcus aureus were inoculated into tryptic soy broth containing 0.0139 ?Ci of 14C glucose/ml of medium. Detection times ranged from 10 to 3 hr for inocula of 100 to 104 cells/ml of broth. Heat-shocked spores of Clostridium sporogenes or C. botulinum were incubated in tryptic soy broth supplemented with Thiotone and NaHCO3. The medium was rendered anaerobic with N2. Spores were detected when 0.0833 ?Ci of labeled glucose was available/ml of medium but not when 0.0139 ?Ci of glucose was present/ml. The spores required 3 to 4 hr longer for detection than did comparable numbers of aerobic vegetative cells. The results demonstrate the importance of availability of sufficient label in the media and the potential of the application of this technique for sterility testing of foods.
Previte, Joseph J.
Intraband radiometric performance of the Landsat Thematic Mappers.
Radiometric characteristics have been examined of the Landsat-4 and Landsat-5 Thematic Mappers (TMs) that can be established without absolute calibration of spectral data. This analysis is based on radiometrically and geometrically raw (B-type) data of both uniform (flat-field) and high-contrast scenes. Subscenes selected for uniform radiance were used to characterized subtle radiometric differences and noise problems. Although the general performance of the Thematic Mappers is excellent, various anomalies that have a magnitude of a few digital levels (DN) or less are quantified. -from Authors
Kieffer, H. H.; Cook, D. A.; Eliason, E. M.; Eliason, P. T.
Radiometric detection of yeasts in blood cultures of cancer patients
During a 12-month period, 19,457 blood cultures were collected. Yeasts were isolated from 193 cultures derived from 76 cancer patients. Candida albicans or Candida tropicalis accounted for 79% of isolates. Of the three methods compared, the radiometric method required 2.9 days to become positive, blind subculture required 2.6 days, and Gram stains required 1 day. However, the radiometric method was clearly superior in detecting positive cultures, since 73% of all cultures were first detected radiometrically, 22% were detected by subculture, and only 5% were detected by Gram stain. Although 93% of the isolates were detected by aerobic culture, five (7%) isolates were obtained only from anaerobic cultures. Seven days of incubation appear to be sufficient for the radiometric detection of yeasts.
Hopfer, R.L.; Orengo, A.; Chesnut, S.; Wenglar, M.
Notes on the Radiometric and Geochemical Survey of Leyte Island.
National Technical Information Service (NTIS)
Radioactivity measurements using the Scintrex GIS-4 portable scintillometer were conducted along the periphery of the island. These radiometric readings as well as sediments were obtained along the streams draining into the sea. A total of 174 stream sedi...
G. Santos C. Samonte R. Almeda R. Ranes J. Salvado
Panay Car-Borne Radiometric and Geochemical Surveys.
National Technical Information Service (NTIS)
A car-borne radiometric survey and stream sediments collection were conducted in Panay and Guimaras Islands. An area in Nabas, Aklan, situated in the northwestern tip of Panay (Buruanga Peninsula) which indicated 2 to 3 times above background radioactivit...
G. Santos C. Samonte R. Almeda R. Ranes J. Salvado
Understanding Satellite Characterization Knowledge Gained from Radiometric Data.
National Technical Information Service (NTIS)
This paper presents a framework for determining satellite characterization knowledge, in the form of estimated parameter uncertainties, from radiometric observation type, quantity, quality, and in combinations. The approach combines complex forward modeli...
A. Harms C. Sabol C. J. Wetterer K. Hamada K. Luu K. T. Allfriend
Mississippi Valley-type lead-zinc deposits through geological time: Implications from recent age-dating research
Remarkable advances in age dating Mississippi Valley-type (MVT) lead-zinc deposits provide a new opportunity to understand how and where these deposits form in the Earth's crust. These dates are summarized and examined in a framework of global tectonics, paleogeography, fluid migration, and paleoclimate. Nineteen districts have been dated by paleomagnetic and/or radiometric methods. Of the districts that have both paleomagnetic and radiometric dates, only the Pine Point and East Tennessee districts have significant disagreements. This broad agreement between paleomagnetic and radiometric dates provides added confidence in the dating techniques used. The new dates confirm the direct connection between the genesis of MVT lead-zinc ores with global-scale tectonic events. The dates show that MVT deposits formed mainly during large contractional tectonic events at restricted times in the history of the Earth. Only the deposits in the Lennard Shelf of Australia and Nanisivik in Canada have dates that correspond to extensional tectonic events. The most important period for MVT genesis was the Devonian to Permian time, which corresponds to a series of intense tectonic events during the assimilation of Pangea. The second most important period for MVT genesis was Cretaceous to Tertiary time when microplate assimilation affected the western margin of North America and Africa-Eurasia. There is a notable paucity of MVT lead-zinc ore formation following the breakup of Rodinia and Pangea. Of the five MVT deposits hosted in Proterozoic rocks, only the Nanisivik deposit has been dated as Proterozoic. The contrast in abundance between SEDEX and MVT lead-zinc deposits in the Proterozoic questions the frequently suggested notion that the two types of ores share similar genetic paths. The ages of MVT deposits, when viewed with respect to the orogenic cycle in the adjacent orogen suggest that no single hydrologic model can be universally applied to the migration of the ore fluids. However, topographically driven models best explain most MVT districts. The migration of MVT ore fluids is not a natural consequence of basin evolution; rather, MVT districts formed mainly where platform carbonates had some hydrological connection to orogenic belts. There may be a connection between paleoclimate and the formation of some MVT deposits. This possible relationship is suggested by the dominance of evaporated seawater in fluid inclusions in MVT ores, by hydrological considerations that include the need for multiple-basin volumes of ore fluid to form most MVT districts, and the need for adequate precipitation to provide sufficient topographic head for topographically-driven fluid migration. Paleoclimatic conditions that lead to formation of evaporite conditions but yet have adequate precipitation to form large hydrological systems are most commonly present in low latitudes. For the MVT deposits and districts that have been dated, more than 75% of the combined metal produced are from deposits that have dates that correspond to assembly of Pangea in Devonian through Permian time. The exceptional endowment of Pangea and especially, North America with MVT lead-zinc deposits may be explained by the following: (1) Laurentia, which formed the core of North America, stayed in low latitudes during the Paleozoic, which allowed the development of vast carbonate platforms; (2) intense orogenic activity during the assembly of Pangea created ground preparation for many MVT districts through far-field deformation of the craton; (3) uplifted orogenic belts along Pangean suture zones established large-scale migration of basin fluids; and (4) the location of Pangea in low latitudes with paleoclimates with high evaporation rates led to the formation of brines by the evaporation of seawater and infiltration of these brines into deep basin aquifers during Pangean orogenic events.
Leach, D. L.; Bradley, D.; Lewchuk, M. T.; Symons, D. T. A.; De Marsily, G.; Brannon, J.
Mississippi Valley-type lead-zinc deposits through geological time: implications from recent age-dating research
NASA Astrophysics Data System (ADS)
Remarkable advances in age dating Mississippi Valley-type (MVT) lead-zinc deposits provide a new opportunity to understand how and where these deposits form in the Earth's crust. These dates are summarized and examined in a framework of global tectonics, paleogeography, fluid migration, and paleoclimate. Nineteen districts have been dated by paleomagnetic and/or radiometric methods. Of the districts that have both paleomagnetic and radiometric dates, only the Pine Point and East Tennessee districts have significant disagreements. This broad agreement between paleomagnetic and radiometric dates provides added confidence in the dating techniques used. The new dates confirm the direct connection between the genesis of MVT lead-zinc ores with global-scale tectonic events. The dates show that MVT deposits formed mainly during large contractional tectonic events at restricted times in the history of the Earth. Only the deposits in the Lennard Shelf of Australia and Nanisivik in Canada have dates that correspond to extensional tectonic events. The most important period for MVT genesis was the Devonian to Permian time, which corresponds to a series of intense tectonic events during the assimilation of Pangea. The second most important period for MVT genesis was Cretaceous to Tertiary time when microplate assimilation affected the western margin of North America and Africa-Eurasia. There is a notable paucity of MVT lead-zinc ore formation following the breakup of Rodinia and Pangea. Of the five MVT deposits hosted in Proterozoic rocks, only the Nanisivik deposit has been dated as Proterozoic. The contrast in abundance between SEDEX and MVT lead-zinc deposits in the Proterozoic questions the frequently suggested notion that the two types of ores share similar genetic paths. The ages of MVT deposits, when viewed with respect to the orogenic cycle in the adjacent orogen suggest that no single hydrologic model can be universally applied to the migration of the ore fluids. However, topographically driven models best explain most MVT districts. The migration of MVT ore fluids is not a natural consequence of basin evolution; rather, MVT districts formed mainly where platform carbonates had some hydrological connection to orogenic belts. There may be a connection between paleoclimate and the formation of some MVT deposits. This possible relationship is suggested by the dominance of evaporated seawater in fluid inclusions in MVT ores, by hydrological considerations that include the need for multiple-basin volumes of ore fluid to form most MVT districts, and the need for adequate precipitation to provide sufficient topographic head for topographically-driven fluid migration. Paleoclimatic conditions that lead to formation of evaporite conditions but yet have adequate precipitation to form large hydrological systems are most commonly present in low latitudes. For the MVT deposits and districts that have been dated, more than 75% of the combined metal produced are from deposits that have dates that correspond to assembly of Pangea in Devonian through Permian time. The exceptional endowment of Pangea and especially, North America with MVT lead-zinc deposits may be explained by the following: (1) Laurentia, which formed the core of North America, stayed in low latitudes during the Paleozoic, which allowed the development of vast carbonate platforms; (2) intense orogenic activity during the assembly of Pangea created ground preparation for many MVT districts through far-field deformation of the craton; (3) uplifted orogenic belts along Pangean suture zones established large-scale migration of basin fluids; and (4) the location of Pangea in low latitudes with paleoclimates with high evaporation rates led to the formation of brines by the evaporation of seawater and infiltration of these brines into deep basin aquifers during Pangean orogenic events.
Leach, David L.; Bradley, Dwight; Lewchuk, Michael T.; Symons, David T.; de Marsily, Ghislain; Brannon, Joyce
New radiometric dating constrains the time for initiation of the Karakorum fault zone (KFZ), SW Tibet
The Karakorum fault zone (KFZ), composed of strike-slip faults, has played an important role in intra-continental deformation during the Cenozoic convergence between the Indian and Eurasian plates. However, the spatial and temporal evolution of the KFZ remains under debate. This paper reports new zircon U�Pb Sensitive High Resolution Ion MicroProbe (SHRIMP) and biotite 40Ar\\/39Ar ages for samples from the fault
Shifeng Wang; Xiaomin Fang; Qingzhou Lai; Dewen Zheng; Yanbin Wang
Radiometric dating of recent lake sediments from a highly eroded area in semiarid Tanzania
Semiarid regions are vulnerable environments with a series of important and often discussed problems such as land degradation, water scarcity and desertification. These regions are dynamic and respond quickly to climatic and environmental changes. Unlike lakes in temperate zones, lakes in semiarid regions are yet poorly utilized as climatic and environmental indicators. In this study aquatic deposits are used to
Farid El-Daoushy; Mats G. Eriksson
New radiometric dating of volcanic ash layers in Periadriatic foredeep basin system, Italy
New geochronological data are reported for two key ash beds interbedded in Upper Miocene (Messinian)�Early Pleistocene rocks at Maccarone, Bellante, and Mosciano S. Angelo on the Adriatic side of the Italian peninsula. Major element chemistry of glass shards was determined with electron microprobe analysis on the younger key bed. The older, Messinian-age ash bed, sampled at Maccarone, yields a corrected
G Bigazzi; F. P Bonadonna; E Centamore; G Leone; M Mozzi; S Nisio; G Zanchetta
New radiometric dating of the dykes from the Hurd Peninsula, Livingston Island, South Shetland Islands
Fifteen new K�Ar ages in the range of 79�31Ma are partially confirmed by three 40Ar\\/39Ar plateaus and isochron data of 64.9�0.4, 55.5�0.1 and 52.8�0.6Ma. The new geochronological data reveal a much more detailed picture of the subduction imprint in the Hurd Peninsula. Using cutting relationships, the dyke emplacement history is divided into four episodes. The Late Cretaceous�Paleocene dykes in the
X. Zheng; B. Kamenov; H. Sang; P. Monchev
Fitting straight lines and planes with an application to radiometric dating
Conventional practice in geochronology is to fit a straight line or ``isochron'' to data consisting of two isotopic ratios by a method (e.g. that of York, 1966, 1969, or perhaps the more modern version of Titterington and Haliday, 1979) that takes into account that fact that both ratios are measured with error. In this paper we use matrix algebra to
John T. Kent; Geoffrey S. Watson; Tullis C. Onstott
Radiometric dating of three large volume flank collapses in the Lesser Antilles Arc
It is now recognised that flank collapses are a recurrent process in the evolution of the Lesser Antilles Arc volcanoes. Large magnitude debris-avalanche deposits have been identified off the coast of Dominica, Martinique and St. Lucia, with associated volumes up to 20�km3 [Deplus, C., Le Friant, A., Boudon, G., Komorowski, J.-C., Villemant, B., Harford, C., S�goufin, J., Chemin�e, J.-L., 2001.
A. Samper; X. Quidelleur; G. Boudon; A. Le Friant; J. C. Komorowski
Radiometric dating of young MORB using the 40Ar39Ar incremental heating method
Determination of reliable crystallization ages by K-Ar methods for young (<1 Ma), fresh basalts from the seafloor has been frustrated by several effects. The small amounts of radiogenic 40Ar developed over these timescales in such low-K rocks are difficult to resolve from predominantly atmospheric 40Ar. An additional concern is that mantle-derived 40Ar may not be totally outgassed when magmas quench
R. A. Duncan; L. G. Hogan
In Situ Radiometric Dating of Aqueously Formed Carbonates in Sutter's Mill
NASA Astrophysics Data System (ADS)
We report Manganese-Chromium systematics for dolomite grains in the Sutter's Mill meteorite, section SM-51. Measurements yield a well-defined isochron with aqueous alteration ages comparable to CM and CI chondrites.
Jilly, C. E.; Huss, G. R.; Nagashima, K.; Yin, Q.-Z.; Sugiura, N.; Krot, A. N.
Further results of radiometric calibration of a multifrequency airborne SAR system
NASA Astrophysics Data System (ADS)
Further results from field experiments to radiometrically correct a multifrequency airborne SAR system are presented. Three frequencies of SAR data (X-, C-, and L-band) at VV polarization were collected over a target array of calibrated trihedral corner reflectors over a 2-week period in summer 1988. For all three frequencies, data collected on one date are utilized to absolutely calibrate data on a second date. The rms errors for this calibration procedure are shown to be less than 1 dB for all three frequencies. In addition, for the L-VV channel, it is shown that the system stability over the entire period of calibration flights (which is the limiting factor for absolute and relative between-scene calibration) was also less than 1 dB.
Kasischke, Eric S.; Gineris, Denise J.
Phoretic and Radiometric Force Measurements on Microparticles in Microgravity Conditions
NASA Technical Reports Server (NTRS)
Thermophoretic, diffusiophoretic and radiometric forces on microparticles are being measured over a wide range of gas phase and particle conditions using electrodynamic levitation of single particles to simulate microgravity conditions. The thermophoretic force, which arises when a particle exists in a gas having a temperature gradient, is measured by levitating an electrically charged particle between heated and cooled plates mounted in a vacuum chamber. The diffusiophoretic force arising from a concentration gradient in the gas phase is measured in a similar manner except that the heat exchangers are coated with liquids to establish a vapor concentration gradient. These phoretic forces and the radiation pressure force acting on a particle are measured directly in terms of the change in the dc field required to levitate the particle with and without the force applied. The apparatus developed for the research and the experimental techniques are discussed, and results obtained by thermophoresis experiments are presented. The determination of the momentum and energy accommodation coefficients associated with molecular collisions between gases molecules and particles and the measurement of the interaction between electromagnetic radiation and small particles are of particular interest.
Davis, E. James
Blast investigation by fast multispectral radiometric analysis
NASA Astrophysics Data System (ADS)
Knowledge regarding the processes involved in blasts and detonations is required in various applications, e.g. missile interception, blasts of high-explosive materials, final ballistics and IED identification. Blasts release large amount of energy in short time duration. Some part of this energy is released as intense radiation in the optical spectral bands. This paper proposes to measure the blast radiation by a fast multispectral radiometer. The measurement is made, simultaneously, in appropriately chosen spectral bands. These spectral bands provide extensive information on the physical and chemical processes that govern the blast through the time-dependence of the molecular and aerosol contributions to the detonation products. Multi-spectral blast measurements are performed in the visible, SWIR and MWIR spectral bands. Analysis of the cross-correlation between the measured multi-spectral signals gives the time dependence of the temperature, aerosol and gas composition of the blast. Farther analysis of the development of these quantities in time may indicate on the order of the detonation and amount and type of explosive materials. Examples of analysis of measured explosions are presented to demonstrate the power of the suggested fast multispectral radiometric analysis approach.
Devir, A. D.; Bushlin, Y.; Mendelewicz, I.; Lessin, A. B.; Engel, M.
Precise Crystallization Age of the Bushveld Complex, South Africa: Direct Dating of the Platiniferous Merensky Reef Using the Zircon U-Pb Chemical Abrasion ID-TIMS Technique
NASA Astrophysics Data System (ADS)
Determining the age of the Bushveld Complex, the world's largest layered intrusion and host to the majority of the known resources of platinum group elements, chromium and vanadium, has been difficult given the very low abundance of U-bearing minerals in the ultramafic-mafic cumulate rocks that comprise the body. This study provides a precise crystallization age for this giant layered intrusion and associated PGE mineralization, and allows for a re-evaluation of the duration and areal extent of Bushveld-related magmatic activity. Abundant, clear and colorless, anhedral zircon grains were separated from a sample of pegmatoidal feldspathic orthopyroxenite collected from the Merensky Reef in the West Mine (Townlands Shaft), Rustenburg Section. Low-U (21-105 ppm) zircon occurs with interstitial biotite and is locally directly in contact with sulfide. The zircon grains were subjected to different pre-treatment methods (no pre-treatment, air abrasion, and chemical abrasion [CA]) and isotope ratios for individual grains were analyzed by ID-TIMS. U-Pb data for the unabraded and air-abraded grains, and leachates from the CA procedure, are slightly discordant (0.1-1.6%) and yield overlapping 207Pb/206Pb dates ranging from 2052.5 to 2058.9 Ma. For the CA zircon grains (n=6), all data are concordant and give a Concordia age of 2054.3 � 2.5 Ma (2sd, decay-constant errors included), which is interpreted as the age of crystallization of the Merensky Reef. This age is within error of published ages for the overlying, and locally cross-cutting, Bushveld or Lebowa granite suite, which implies that the entire Bushveld Complex was emplaced within a 2-3 myr interval. Comparison with ages from satellite intrusions (e.g. Moshaneng, Botswana; Uitkomst, South Africa) indicates that the Bushveld magmatic event at ca. 2054 Ma was regionally extensive across the northern Kaapvaal Craton and is consistent with relatively rapid emplacement of mantle-derived magmas along the Thabazimbi-Murchison Lineament, a 500 km-long, lithosphere-scale tectonic break.
Scoates, J. S.; Friedman, R. M.
A comparison of the lichenometric and Schmidt hammer dating techniques based on data from the proglacial areas of some Icelandic glaciers
NASA Astrophysics Data System (ADS)
Measurements of Rhizocarpon section and Schmidt hammer R-values are reported from the proglacial geomorphic features on the forelands of the Icelandic glaciers of Kv?��rj�kull, H�l�rj�kull and Heinabergsj�kull (�r�fi and south Vatnaj�kull), Sandfellsj�kull and �ldufellsj�kull (east M�rdalsj�kull), and Br��rj�kull, Eyjabakkaj�kull and west Sn�fell (north Vatnaj�kull). These data are used in reconstructions of patterns of glacier recession since the Little Ice Age maximum, and the geomorphic signals of climatic versus non-climatic events are discussed. Age control was obtained from various dated substrates by utilizing historical accounts, aerial photographs and grave stones. Three lichen growth rates are calculated: (a) 0.51 mm a -1 (corrected to 0.50 mm a -1) with a colonization lag time of <16 yr for the arid forelands of north Vatnaj�kull; (b) 0.56 mm a -1 with a colonization lag time of 5 yr for the Icelandic southeast coast; and (c) 0.80 mm a -1 with a colonization lag time of 6.5 yr for the south Vatnaj�kull and east M�rdalsj�kull forelands. These compare favourably with a previously published growth rate of 0.44 mm a -1 for the arid north of Iceland. This regional coverage of data allows a comparison between annual precipitation totals and lichen growth rates and the construction of a growth rate prediction curve for Iceland. The success of the Schmidt hammer in differentiating moraines based upon age varied according to the geomorphological setting. Reasonable R-value/lichen size correlations were obtained on the east M�rdalsj�kull and Heinabergsj�kull forelands where unrestricted glacier advance into lowlands allows for a higher degree of debris surface freshening by direct glacial processes. Weak correlations were obtained at Kv?��rj�kull, where the glacier was restricted by a precursor latero-frontal moraine loop and therefore the debris comprising the Little Ice Age recessional moraines was diluted with material of various ages being reworked by mass movement from the precursor moraine loop. Similar problems arise in areas affected by surging glaciers, such as Br��rj�kull and Eyjabakkaj�kull. It appears that an accurate R-value age-prediction curve can not be constructed for a timescale of <100 yr in Iceland.
Evans, D. J. A.; Archer, S.; Wilson, D. J. H.
Absolute Radiometric Calibration of Narrow-Swath Imaging Sensors with Reference to Non-Coincident Wide-Swath Sensors
NASA Technical Reports Server (NTRS)
An inter-calibration method is developed to provide absolute radiometric calibration of narrow-swath imaging sensors with reference to non-coincident wide-swath sensors. The method predicts at-sensor radiance using non-coincident imagery from the reference sensor and knowledge of spectral reflectance of the test site. The imagery of the reference sensor is restricted to acquisitions that provide similar view and solar illumination geometry to reduce uncertainties due to directional reflectance effects. Spectral reflectance of the test site is found with a simple iterative radiative transfer method using radiance values of a well-understood wide-swath sensor and spectral shape information based on historical ground-based measurements. At-sensor radiance is calculated for the narrow-swath sensor using this spectral reflectance and atmospheric parameters that are also based on historical in situ measurements. Results of the inter-calibration method show agreement on the 2 5 percent level in most spectral regions with the vicarious calibration technique relying on coincident ground-based measurements referred to as the reflectance-based approach. While the variability of the inter-calibration method based on non-coincident image pairs is significantly larger, results are consistent with techniques relying on in situ measurements. The method is also insensitive to spectral differences between the sensors by transferring to surface spectral reflectance prior to prediction of at-sensor radiance. The utility of this inter-calibration method is made clear by its flexibility to utilize image pairings with acquisition dates differing in excess of 30 days allowing frequent absolute calibration comparisons between wide- and narrow-swath sensors.
McCorkel, Joel; Thome, Kurtis; Lockwood, Ronald
Improved accuracy of U-Pb zircon dating by selection of more concordant fractions using a high gradient magnetic separation technique
NASA Astrophysics Data System (ADS)
A loop of soft iron wire or a paper clip or a ferromagnetic grid mounted between the poles of an electromagnet picks up and allows further magnetic separation of zircons previously found to be non-magnetic on a Frantz Isodynamic Separator. Tests on previously analysed samples indicate that most such zircons that are fairly discordant (say ~10%) can be picked up and isolated from associated grains that are more concordant. Tests on new samples indicate that even when most grains can be picked up the last few percent of the sample contain less uranium, and are more concordant than the bulk sample. The degree of discordance is the dominant factor affecting the uncertainty of U-Pb zircon ages both because of the error amplification in projections, and because the assumption of a simple two-stage system may not be valid. Only by eliminating or reducing discordance can errors approaching the uncertainty in a single analysis, say �2 m.y. for 2700 m.y. rocks, be achieved. Rutile normally concentrated with zircon as non-magnetic has been successfully removed from a small amount of low uranium zircon, using the high intensity separation technique.
Krogh, T. E.
A Kalman Approach to Lunar Surface Navigation using Radiometric and Inertial Measurements
NASA Technical Reports Server (NTRS)
Future lunar missions supporting the NASA Vision for Space Exploration will rely on a surface navigation system to determine astronaut position, guide exploration, and return safely to the lunar habitat. In this report, we investigate one potential architecture for surface navigation, using an extended Kalman filter to integrate radiometric and inertial measurements. We present a possible infrastructure to support this technique, and we examine an approach to simulating navigational accuracy based on several different system configurations. The results show that position error can be reduced to 1 m after 5 min of processing, given two satellites, one surface communication terminal, and knowledge of the starting position to within 100 m.
Chelmins, David T.; Welch, Bryan W.; Sands, O. Scott; Nguyen, Binh V.
Ar-Ar Dating of Martian Chassignites, NWA2737 and Chassigny, and Nakhlite MIL03346
NASA Technical Reports Server (NTRS)
Until recently only three nakhlites and one chassignite had been identified among martian meteorites. These four exhibit very similar radiometric ages and cosmic ray exposure (CRE) ages, indicating that they may have derived from a common location on Mars and were ejected into space by a single impact. This situation is quite different from that of martian shergottites, which exhibit a range of radiometric ages and CRE ages (1). Recently, several new nakhlites and a new martian dunite (NWA2737) have been recognized. Here we report our results of Ar-39-Ar-40 dating for the MIL03346 nakhlite and the NWA2737 "chassignite", along with new results on Chassigny.
Bogard, D. D.; Garrison, D. H.
Radioactive Dating: A Method for Geochronology.
ERIC Educational Resources Information Center
Gives historical background on the discovery of natural radiation and discusses various techniques for using knowledge of radiochemistry in geochronological studies. Indicates that of these radioactive techniques, Potassium-40/Argon-40 dating is used most often. (JN)
Rowe, M. W.
ASD FieldSpec Calibration Setup and Techniques
NASA Technical Reports Server (NTRS)
This paper describes the Analytical Spectral Devices (ASD) Fieldspec Calibration Setup and Techniques. The topics include: 1) ASD Fieldspec FR Spectroradiometer; 2) Components of Calibration; 3) Equipment list; 4) Spectral Setup; 5) Spectral Calibration; 6) Radiometric and Linearity Setup; 7) Radiometric setup; 8) Datadets Required; 9) Data files; and 10) Field of View Measurement. This paper is in viewgraph form.
Olive, Dan
A Kinetic Model for Scattered Radiometric Ages in HP/UHP Terrains Using the Western Gneiss Region of the Scandinavian Caledonides as an Example
NASA Astrophysics Data System (ADS)
Attempts to date the "peak" of metamorphism in HP/UHP terrains are complicated by radiometric dates that scatter over significant time periods: on the order of tens of millions of years in some terrains. For example, eclogites dated by Sm-Nd mineral isochron and U-Pb zircon techniques in the Western Gneiss Region (WGR) of the Norwegian Caledonides give ages that range from 402 to 422 Ma (the oldest age is a re-determination of an eclogite previously dated at 447 Ma). Some recent studies have proposed that the older ages should be discarded and the youngest ages should taken to date the HP/UHP metamorphism that accompanied the collision of Baltica and Laurentia during the Scandian Orogeny. This interpretation implies that HP/UHP metamorphism was a discrete, short-lived event that occurred during or shortly after the achievement of peak temperatures. However, if HP/UHP conditions are achieved through the subduction of continental crust into the mantle, eclogite-facies assemblages have the potential to form throughout the interval that the crust is within the eclogite stability field, during both subduction and eduction. Recent evidence suggests that eclogitization requires the introduction of fluids or the application of strain or the action of some other catalytic process and that where these processes do not occur the rocks can persist metastably as non-eclogite facies assemblages. This means that eclogitization can occur locally, wherever and whenever fluids are introduced or strain is localized, rather than occurring coherently within a short interval throughout the entire terrene. If so, all determined ages from the WGR could be correct with each one dating the formation of eclogite-facies assemblages in a particular place at a particular time. If so, the WGR resided at depths within the eclogite facies stability field for ca. 20 m.y. A testable consequence of this model is that eclogites from the part of the slab that was subducted to the deepest levels should have both the oldest and youngest eclogites with the ages dating the entry into, and the departure from, respectively, the eclogite stability field.
Brueckner, H. K.
Radiometric Measurement Comparisons Using Transfer Radiometers in Support of the Calibration of NASA's Earth Observing System (EOS) Sensors
NASA Technical Reports Server (NTRS)
EOS satellite instruments operating in the visible through the shortwave infrared wavelength regions (from 0.4 micrometers to 2.5 micrometers) are calibrated prior to flight for radiance response using integrating spheres at a number of instrument builder facilities. The traceability of the radiance produced by these spheres with respect to international standards is the responsibility of the instrument builder, and different calibration techniques are employed by those builders. The National Aeronautics and Space Administration's (NASA's) Earth Observing System (EOS) Project Science Office, realizing the importance of preflight calibration and cross-calibration, has sponsored a number of radiometric measurement comparisons, the main purpose of which is to validate the radiometric scale assigned to the integrating spheres by the instrument builders. This paper describes the radiometric measurement comparisons, the use of stable transfer radiometers to perform the measurements, and the measurement approaches and protocols used to validate integrating sphere radiances. Stable transfer radiometers from the National Institute of Standards and Technology, the University of Arizona Optical Sciences Center Remote Sensing Group, NASA's Goddard Space Flight Center, and the National Research Laboratory of Metrology in Japan, have participated in these comparisons. The approaches used in the comparisons include the measurement of multiple integrating sphere lamp levels, repeat measurements of select lamp levels, the use of the stable radiometers as external sphere monitors, and the rapid reporting of measurement results. Results from several comparisons are presented. The absolute radiometric calibration standard uncertainties required by the EOS satellite instruments are typically in the +/- 3% to +/- 5% range. Preliminary results reported during eleven radiometric measurement comparisons held between February 1995 and May 1998 have shown the radiance of integrating spheres agreed to within +/- 2.5% from the average at blue wavelengths and to within +/- 1.7% from the average at red and near infrared wavelengths. This level of agreement lends confidence in the use of the transfer radiometers in validating the radiance scales assigned by EOS instrument calibration facilities to their integrating sphere sources.
Butler, James J.; Johnson, B. Carol; Brown, Steven W.; Yoon, Howard W.; Barnes, Robert A.; Markham, Brian L.; Biggar, Stuart F.; Zalewski, Edward F.; Spyak, Paul R.; Cooper, John W.; Sakuma, Fumihiro
Spectral, spatial and radiometric factors in cover type discrimination
NASA Technical Reports Server (NTRS)
The influence of spatial, spectral, and radiometric resolutions on the utilization of Thematic Mapper (TM) and Multispectral Scanner (MSS) data is assessed quantitatively using a 2 x 2 x 2 factorial design experiment. Eight possible factor combinations were examined for agricultural, urban, forestry, range, and water types of land covers for three levels of information. Spectral bandwidths were configured to simulate all four Landsat MSS channels and Landsat TM channels 1, 2, 3, 4, and 7. By means of bar charts and tables it is shown that the 8-bit radiometric and 75-meter spatial resolutions provide a higher overall accuracy than the 6-bit radiometric and 25-meter spatial resolutions. Spectrally, the difference between the four MSS channels and five TM channel configurations is noted to be insignificant.
Alexander, D.; Buis, J.; Acevedo, W.; Wrigley, R.
In-flight absolute radiometric calibration of the thematic mapper
NASA Technical Reports Server (NTRS)
In order to determine temporal changes of the absolute radiometric calibration of the entire TM system in flight spectroradiometric measurements of the ground and the atmosphere were made simultaneously with TM image collections over the White Sands, New Mexico area. By entering the measured values in an atmospheric radiative transfer program, the radiance levels in four of the spectral bands of the TM were determined, band 1:0.45 to 0.52 micrometers, band 2:0.53 to 0.61 micrometers band 3:0.62 to 0.70 micrometers and 4:0.78 to 0.91 micrometers. These levels were compared to the output digital counts from the detectors that sampled the radiometrically measured ground area, thus providing an absolute radiometric calibration of the entire TM system utilizing those detectors.
Castle, K. R.; Holm, R. G.; Kastner, C. J.; Palmer, J. M.; Slater, P. N.; Dinguirard, M.; Ezra, C. E.; Jackson, R. D.; Savage, R. K.
Radiometric Calibration of the Earth Observing System's Imaging Sensors
NASA Technical Reports Server (NTRS)
The work on the grant was mainly directed towards developing new, accurate, redundant methods for the in-flight, absolute radiometric calibration of satellite multispectral imaging systems and refining the accuracy of methods already in use. Initially the work was in preparation for the calibration of MODIS and HIRIS (before the development of that sensor was canceled), with the realization it would be applicable to most imaging multi- or hyper-spectral sensors provided their spatial or spectral resolutions were not too coarse. The work on the grant involved three different ground-based, in-flight calibration methods reflectance-based radiance-based and diffuse-to-global irradiance ratio used with the reflectance-based method. This continuing research had the dual advantage of: (1) developing several independent methods to create the redundancy that is essential for the identification and hopefully the elimination of systematic errors; and (2) refining the measurement techniques and algorithms that can be used not only for improving calibration accuracy but also for the reverse process of retrieving ground reflectances from calibrated remote-sensing data. The grant also provided the support necessary for us to embark on other projects such as the ratioing radiometer approach to on-board calibration (this has been further developed by SBRS as the 'solar diffuser stability monitor' and is incorporated into the most important on-board calibration system for MODIS)- another example of the work, which was a spin-off from the grant funding, was a study of solar diffuser materials. Journal citations, titles and abstracts of publications authored by faculty, staff, and students are also attached.
Slater, Philip N. (Principal Investigator)
Ellipsoidal geometry in asteroid thermal models - The standard radiometric model
NASA Technical Reports Server (NTRS)
The major consequences of ellipsoidal geometry in an othewise standard radiometric model for asteroids are explored. It is shown that for small deviations from spherical shape a spherical model of the same projected area gives a reasonable aproximation to the thermal flux from an ellipsoidal body. It is suggested that large departures from spherical shape require that some correction be made for geometry. Systematic differences in the radii of asteroids derived radiometrically at 10 and 20 microns may result partly from nonspherical geometry. It is also suggested that extrapolations of the rotational variation of thermal flux from a nonspherical body based solely on the change in cross-sectional area are in error.
Brown, R. H.
Discrepancy between growth of Coccidioides immitis in bacterial blood culture media and a radiometric growth index
Spherules of Coccidioides immitis grew readily after inoculation in vented trypticase soy broth, biphasic brain heart infusion media, and aerobic tryptic soy broth bottles used in a radiometric system (BACTEC). However, visible growth was not accompanied by a significant radiometric growth index. Growth of C. immitis can be visually detected in routine bacterial blood culture media while the radiometric growth index remains negative.
Ampel, N.M.; Wieden, M.A.
Evaluation of the radiometric integrity of LANDSAT4 Thematic Mapper band 6 data
An approach for experimentally evaluating the radiometric calibration of the LANDSAT-4 band 6 data is described which draws on a method used to radiometrically calibrate the HCMR data which involved underflying the satellite with an infrared line scanner. By extending this technology to higher altitudes experimental radiance data suitable for radiometric calibration of the TM band 6 sensor can be
J. R. Schott
Laboratory for Radiokrypton Dating
NASA Astrophysics Data System (ADS)
Due to its simple production and transport processes in the terrestrial environment, the long-lived noble-gas isotope 81Kr (half-life = 230 kyr) is the ideal tracer for studying old water and ice in the age range of 10^5-10^6 years, a range beyond the reach of 14C. 81Kr dating, a concept pursued in the past four decades by numerous laboratories employing a variety of techniques, is now available for the first time to the earth science community at large. This is made possible by the development of ATTA-3 (Jiang et al., GCA 91, 1-6; 2012), an efficient and selective atom counter based on the Atom Trap Trace Analysis method (Chen et al., Science 286, 1139-1141; 1999). The instrument is capable of measuring both 81Kr/Kr and 85Kr/Kr ratios of environmental samples in the range of 10^-14-10^-10. For 81Kr-dating in the age range of 150 - 1,500 kyr, the required sample size is 5 - 10 micro-L STP of krypton gas, which can be extracted from approximately 100 - 200 kg of water or 40 - 80 kg of ice. For 85Kr/Kr analysis, the required sample size is generally smaller by an order of magnitude because of the isotope's higher initial abundance in the atmosphere. The Laboratory for Radiokrypton Dating is currently equipped to analyze up to 120 samples per year. With future equipment upgrades, this limit can be increased as demand grows. In the period since November 2011, the Laboratory has measured both 81Kr/Kr and 85Kr/Kr ratios in over 50 samples that had been extracted by collaborators from six different continents. The samples were from groundwater wells in the Great Artesian Basin (Australia), Guarani Aquifer (Brazil), and Locust Grove (Maryland); from brine wells of the Waste Isolation Pilot Plant (New Mexico); from geothermal steam vents in Yellowstone National Park; from near-surface ice at Taylor Glacier, Antarctica; and from deep mines in South Africa. Sample collection and purification was performed by groups including the University of Illinois at Chicago, University of Bern, and International Atomic Energy Agency. ATTA is a laser-based atom counting method, not a mass spectrometry method. A magneto-optical trap is used to capture neutral atoms (rather than ions) of the desired isotope using laser beams. A photo-sensor detects the laser induced fluorescence emitted by the individual trapped atoms. ATTA is unique among trace analysis techniques in that it is free of interferences from any other isotopes, isobars, atomic or molecular species. In an experiment demonstrating that ATTA-3 can analyze 39Ar/Ar ratios in environmental samples, no interference from other atomic or molecular species was observed at the 1x10^-16 level (Jiang et al., Phys. Rev. Lett. 106, 103001; 2011). This work proved the feasibility of performing 39Ar dating using the ATTA method. We are supported by DOE, Office of Nuclear Physics, under contract DE-AC02-06CH11357, and by Argonne National Laboratory.
Lu, Z.; Bailey, K.; Jiang, W.; M�ller, P.; O'Connor, T. P.; Zappala, J. C.
Sensor Correction and Radiometric Calibration of a 6-BAND Multispectral Imaging Sensor for Uav Remote Sensing
NASA Astrophysics Data System (ADS)
The increased availability of unmanned aerial vehicles (UAVs) has resulted in their frequent adoption for a growing range of remote sensing tasks which include precision agriculture, vegetation surveying and fine-scale topographic mapping. The development and utilisation of UAV platforms requires broad technical skills covering the three major facets of remote sensing: data acquisition, data post-processing, and image analysis. In this study, UAV image data acquired by a miniature 6-band multispectral imaging sensor was corrected and calibrated using practical image-based data post-processing techniques. Data correction techniques included dark offset subtraction to reduce sensor noise, flat-field derived per-pixel look-up-tables to correct vignetting, and implementation of the Brown- Conrady model to correct lens distortion. Radiometric calibration was conducted with an image-based empirical line model using pseudo-invariant features (PIFs). Sensor corrections and radiometric calibration improve the quality of the data, aiding quantitative analysis and generating consistency with other calibrated datasets.
Kelcey, J.; Lucieer, A.
Correcting for nucleogenic ^{36}Cl in cosmogenic ^{36}Cl dating of volcanic rocks from the Erciyes volcano, Central Turkey
NASA Astrophysics Data System (ADS)
Many radiometric methods are suitable for dating lava flows, but none is reliable for routine dating of lava flows younger than 10 ky. The cosmogenic ^{36}Cl method seems promising because it can be applied to any type of rock and laboratory and analytical work is easy and fast. But low cosmogenic ^{36}Cl inventory (after short exposure duration), combined with possible large non-cosmogenic component, makes this technique difficult to apply in a routine fashion. We applied the ^{36}Cl method to date a lava flow and the 14C technique to date the associated ash flow from the Erciyes (Argaeus) volcano, central Turkey. The average of three cosmogenic ^{36}Cl ages is 7.3 \\mp 0.5 ky and the average of two radiocarbon ages is 9.5 \\mp 0.3 ky (calibrated using Calib 5.0). The difference could be due to the overestimation of the calculated nucleogenic ^{36}Cl, which makes up almost one-third of the measured ^{36}Cl. If the nucleogenic component were set to zero, the average ^{36}Cl age would be 10.3 \\mp 0.2 ky. Thus, the ^{36}Cl age should be in the range between 7.3 ky and 10.2 ky, which includes the 14C age near the upper end of the interval. Under the assumption that the 14C age is correct and that the nucleogenic ^{36}Cl has reached a secular equilibrium with the magma, the nucleogenic ^{36}Cl needed to reconcile the ^{36}Cl and 14C ages is only about one-fifth of that previously calculated. In order to investigate this disparity of ages and possible calculating errors of nucleogenic ^{36}Cl, we are analyzing rock samples from where we can directly measure nucleogenic component of ^{36}Cl. This work is important for developing better ways to estimate the nucleogenic ^{36}Cl, which will improve the accuracy of ^{36}Cl dating of young volcanic rocks.
Sarikaya, M. A.; Zreda, M.; Desilets, D.; Ciner, A.; Sen, E.
Radiometric sources for the Los Alamos National Laboratory calibration Laboratory
Los Alamos is developing a laboratory that will support state of the art calibration of moderate-aperture instrumentation (< 40 cm diameter) having high spatial and thermal resolution. Highly accurate calibration in the reflected solar and thermal infrared spectral regions are required for newly developed instrumentation. Radiometric calibration of the instrumentation requires well-characterized, extensive sources of radiation from 0.45 to 12 {mu}m. For wavelengths above 2.5 {mu}m, blackbodies having temperature control and radiometric uniformity to within 100 mK are being designed and will be radiometrically characterized at the National Institute of Standards and Technology (NIST). For the spectral range 0.45--2.5 {mu}m, a ``whitebody`` integrating sphere equipped with tungsten-halogen lamps and enclosed inside a vacuum shroud will be used; this vacuum-compatible extensive standard diffuse source utilizes well-known technology and will be characterized at NIST`s existing facilities. Characterization of instrumental contrast performance for wavelengths, {lambda}, beyond 2.5 {mu}m will utilize a recently designed absolute variable-contrast IR radiometric calibrator, and preliminary data indicate that this calibrator will perform satisfactorily. Conceptual design and status of these extensive broad-band sources and of a monochromatic source to be used for spectral calibrations will be presented.
Maier, W.B. II; Holland, R.; Bender, S.; Byrd, D.; Michaud, F.D.; Moore, S. [Los Alamos National Lab., NM (United States); O`Brian, T.R. [National Inst. of Standards and Technology, Gaithersburg, MD (United States)
Radiometric calibration and monitoring of NOAA AVHRR data for ISCCP
This paper describes the methodology developed to monitor the radiometric calibration of NOAA AVHRR data and to normalize succeeding polar orbiters for the International Satellite Cloud Climatology Project (ISCCP). Results are presented for NOAA-7, -8, and -9 Channel 1 (visible) data and briefly for Channel 4 (thermal infrared) in an appendix. The successful normalization of NOAA-8 and NOAA-9 to NOAA-7
Airborne Radiometrics and Comparison with Activity Measurements in Groundwater
Airborne geophysical measurements including magnetics, electromagnetics and radiometry were carried out in a 312 sqkm large area in eastern Bavaria comprising crystalline rocks and Cenozoic sediments. The helicopter-borne investigations of 2007 were accompanied by ground-borne gamma spectroscopy and radon activity measurements in groundwater outcrops. The comparison of the radiometric data gathered allows to delineate hidden granitic intrusions and to distinguish
G. W. Diepolder; H. Herold; B. Siemon
High speed radiometric measurements of IED detonation fireballs
Continuum emission is predominant in fireball spectral phenomena and in some demonstrated cases, fine detail in the temporal evolution of infrared spectral emissions can be used to estimate size and chemical composition of the device. Recent work indicates that a few narrow radiometric bands may reveal forensic information needed for the explosive discrimination and classification problem, representing an essential step
Matthew T. Spidell; J. Motos Gordon; Jeremey Pitz; Kevin C. Gross; Glen P. Perram
Radiometric Calibration of Osmi Imagery Using Solar Calibration
NASA Astrophysics Data System (ADS)
OSMI (Ocean Scanning Multi-Spectral Imager) raw image data (Level 0) were acquired and radiometrically corrected. We have applied two methods, using solar & dark calibration data from OSMI sensor and comparing with the SeaWiFS data, to the radiometric correction of OSMI raw image data. First, we could get the values of the gain and the offset for each pixel and each band from comparing the solar & dark calibration data with the solar input radiance values, calculated from the transmittance, BRDF (Bidirectional Reflectance Distribution Function) and the solar incidence angle (��,��) of OSMI sensor. Applying this calibration data to OSMI raw image data, we got the two odd results, the lower value of the radiometric corrected image data than the expected value, and the Venetian Blind Effect in the radiometric corrected image data. Second, we could get the reasonable results from comparing OSMI raw image data with the SeaWiFS data, and get a new problem of OSMI sensor.
Lee, Dong-Han; Kim, Yong-Seung
The effects of mesh reflecting surfaces upon radiometric measurements
NASA Technical Reports Server (NTRS)
Reflector antennas with mesh surfaces have been used in ground and space applications primarily for communication systems. How the requirements for mesh surface reflectors are different for microwave radiometric applications is indicated, a method of measuring the anticipated small dissipation losses of gold-plated mesh using a radiometer system is proposed.
Crosswell, W. F.
Application of a radiometric method to the measurement of temperature in self-absorbing gases
NASA Technical Reports Server (NTRS)
A radiometric method for the measurement of gas temperature in self-absorbing gases has been applied in the study of shock-tube-generated flows. This method involves making two absolute-intensity measurements at the same wavelength in a specified gas sample, but using two different path lengths. Experimental results are presented for reflected shock waves in air and in xenon at conditions corresponding to shock velocities from 4 to 10 km/sec and an initial driven tube pressure of 1 torr. These results indicate that, with the technique, temperature measurements with an accuracy of 5% can be carried out. The measurements in air suggest certain facility-related problems, and results obtained in the application of this measurement technique to the investigation of these problems and to the study of radiative cooling phenomena in both air and xenon are presented.
Nerem, R. M.; Bader, J. B.; Dann, J. B.; Culp, M. A.
ERIC Educational Resources Information Center
The phenomenon of violence in interpersonal relationships has been little studied in Russia, and the phenomenon of violence between dating partners has not been the object of scientific interest at all. The study on which the present article is based was designed to obtain information about the violence in dating among students enrolled in�
Lysova, A. V.
Radiometric Spacecraft Tracking for Deep Space Navigation
NASA Technical Reports Server (NTRS)
Interplanetary spacecraft navigation relies on three types of terrestrial tracking observables.1) Ranging measures the distance between the observing site and the probe. 2) The line-of-sight velocity of the probe is inferred from Doppler-shift by measuring the frequency shift of the received signal with respect to the unshifted frequency. 3) Differential angular coordinates of the probe with respect to natural radio sources are nominally obtained via a differential delay technique of (Delta) DOR (Delta Differential One-way Ranging). The accuracy of spacecraft coordinate determination depends on the measurement uncertainties associated with each of these three techniques. We evaluate the corresponding sources of error and present a detailed error budget.
Lanyi, Gabor E.; Border, James S.; Shin, Dong K.
Radiometric millimetric imaging at Roke Manor Research
NASA Astrophysics Data System (ADS)
This paper describes two systems developed by Roke Manor Research in partnership with HMG's Home Office Immigration and Nationality Directorate and which are based upon passive millimetric microwave radiometry techniques. Their purpose is to aid the detection of people concealed in curtain-sided and plastic-sided freight vehicles. The paper covers the basic physics of radiometry, the history of these developments and concludes with an account of the future directions of this work.
Hall, Jason; Harman, Martin L.
UV/VUV radiometric calibrations at SURF II
NASA Technical Reports Server (NTRS)
Since 1981 more than 150 instrument calibrations have been performed on the radiometric instrumentation calibration beamline at the Synchrotron Ultraviolet Radiation Facility (SURF II) at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland. This 300 MeV electron storage ring operates routinely at electron currents greater than 250 mA. The spectrometer calibration beamline provides a continuum of radiation from 4 nm through the visual spectral region in the form of an intense beam with total angular divergence of 1.2 mrad. The probable uncertainty for the flux ranges from about 5 percent at 4 nm to less than 2 percent above 20 nm. The new system will radiometrically trace to SURF II, and thus is expected to reduce the calibration uncertainty for diodes in this region by a factor of five to the 1-2 percent level.
Furst, Mitchell L.; Canfield, L. R.
Radiometric Compensation and Calibration for Radarsat ScanSAR
NASA Technical Reports Server (NTRS)
Due to lack of a standard for modeling the radar echo signal in terms of signal unit and coordinates as well as lack of a standard in designing the gain factors in each stage of a processor, absolute radiometric calibration of a SAR system is usually performed by treating the sensor and processor as one inseparable unit. This often makes the calibration procedure complicated and requiring the involvement of both radar system engineers and processor engineers in the whole process. This paper introduces a standard for modeling the radar echo signal and a standard in designing the gain factor of a ScanSAR processor. In this paper, the radar equation is derived based on the amount of energy instead of the power received from a backscatterer. These efforts lead to simple and easy-to-understand equations for radiometric compensation and calibration.
Jin, Michael Y.
Initial examination of radar imagery of optical radiometric calibration sites
NASA Astrophysics Data System (ADS)
In-flight absolute radiometric calibration is critical for multi-temporal and multi-sensor data comparisons. In the case of vicarious calibration of optical sensors based on ground-level measurements, the test site must be well characterized in spatial, radiometric, spectral, and temporal domains. Remotely sensed data acquired at other wavelengths can contribute to a baseline understanding of ground targets and provide insight into the usefulness of such targets for in-flight calibration of optical sensors. With these considerations in mind, multi-temporal ERS-1 SAR data have been obtained for White Sands, New Mexico, and Lunar Lake and Railroad Valley playas in Nevada. This paper reports on an initial examination of these SAR image data sets and the significant pattern changes observed in the scenes. It is concluded that surface roughness, soil moisture and run-off are major factors giving rise to the observed scene characteristics.
Teillet, Philippe M.; Fedosejevs, Gunar; Gauthier, D.; D'Iorio, Marie A.; Rivard, B.; Budkewitsch, P.
The OLI Radiometric Scale Realization Round Robin Measurement Campaign
NASA Technical Reports Server (NTRS)
A round robin radiometric scale realization was performed at the Ball Aerospace Radiometric Calibration Laboratory in January/February 2011 in support of the Operational Land Imager (OLI) Program. Participants included Ball Aerospace, NIST, NASA Goddard Space Flight Center, and the University of Arizona. The eight day campaign included multiple observations of three integrating sphere sources by nine radiometers. The objective of the campaign was to validate the radiance calibration uncertainty ascribed to the integrating sphere used to calibrate the OLI instrument. The instrument level calibration source uncertainty was validated by quatnifying: (1) the long term stability of the NIST calibrated radiance artifact, (2) the responsivity scale of the Ball Aerospace transfer radiometer and (3) the operational characteristics of the large integrating sphere.
Cutlip, Hansford; Cole,Jerold; Johnson, B. Carol; Maxwell, Stephen; Markham, Brian; Ong, Lawrence; Hom, Milton; Biggar, Stuart
Photocarrier radiometric characterization of semiconductor silicon wafers
NASA Astrophysics Data System (ADS)
As semiconductor devices become increasingly complex, and consequently increasingly expensive to produce, the necessity to improve yield in order to maintain profitability is continuously driving industrial manufacturers to search for more effective characterization tools. Photothermal techniques have been developed over the last several decades as a viable characterization tool for electronic materials. However, they are in general sensitive to both thermal-wave and carrier-density-wave processes in an optically excited semiconductor and these two competing signal generation mechanisms can result in compromised computational accuracy and potential ambiguity of lateral imaging of the electronic properties of a material. In this thesis photocarrier radiometry (PCR), a form of spectrally-integrated modulated room-temperature near-infrared photoluminescence, is presented as a novel non-destructive diagnostic technique for non-contact characterization of semiconductor materials. The signal generation mechanism for PCR is the IR emission and self-reabsorption of IR photons emitted by recombining photogenerated carriers created by an intensity modulated super-bandgap optical source. The IR emission intensity is proportional to the integrated carrier density profile in the sample which is modified by enhanced recombination at defects. The developed technique is utilized for the quantitative determination of the electronic transport parameters, namely recombination lifetime, diffusivity, and surface recombination velocity, and has been applied to the study of two industrially relevant characterization issues, ion implantation dose uniformity monitoring and contamination/defect imaging. The direct correlation between contamination and carrier lifetime in Si allows for generation of contamination/defect concentration images by laterally scanning the sample. The signal dependence of the PCR signal on ion implant dose in silicon is established over a broad range of industrially relevant doses. The modification of the physical structure, and the corresponding change in the electrical and optical properties of the material during ion implantation, is used to develop a model for the optoelectronic response of an ion implanted semiconductor. In addition, a two beam cross-modulation technique is developed and shown to enhance imaging contrast and resolution and to have potential application for low injection level defect imaging. In summary, a semiconductor characterization technique with multiple applications to industrially relevant metrology issues has been developed and is presented in this work.
Shaughnessy, Derrick
BOREAS TE-18, 60-m, Radiometrically Rectified Landsat TM Imagery
NASA Technical Reports Server (NTRS)
The BOREAS TE-18 team used a radiometric rectification process to produce standardized DN values for a series of Landsat TM images of the BOREAS SSA and NSA in order to compare images that were collected under different atmospheric conditions. The images for each study area were referenced to an image that had very clear atmospheric qualities. The reference image for the SSA was collected on 02-Sep-1994, while the reference image for the NSA was collected on 2 1 Jun-1995. The 23 rectified images cover the period of 07-Jul-1985 to 18-Sep-1994 in the SSA and 22-Jun-1984 to 09-Jun-1994 in the NSA. Each of the reference scenes had coincident atmospheric optical thickness measurements made by RSS-11. The radiometric rectification process is described in more detail by Hall et al. (1991). The original Landsat TM data were received from CCRS for use in the BOREAS project. Due to the nature of the radiometric rectification process and copyright issues, the full-resolution (30-m) images may not be publicly distributed. However, this spatially degraded 60-m resolution version of the images may be openly distributed and is available on the BOREAS CD-ROM series. After the radiometric rectification processing, the original data were degraded to a 60-m pixel size from the original 30-m pixel size by averaging the data over a 2- by 2-pixel window. The data are stored in binary image-format files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Activity Archive Center (DAAC).
Hall, Forrest G. (Editor); Knapp, David
The integrated radiometric correction of optical remote sensing imageries
Environmental analysis, management and modelling require detailed and precise land?use\\/land?cover discrimination as initial conditions of land surface characteristics. With the ultimate goal of accurate land surface classification analysis, we devised a fully image?based and physically based correction method (the Integrated Radiometric Correction (IRC) method) considering both the atmospheric and the topographic effects simultaneously, using the information deduced from the satellite
S. Kobayashi; K. Sanga-Ngoie
Towards Core Body Temperature Measurement via Close Proximity Radiometric Sensing
Presented is a noncontact model and radiometric sensor developed to facilitate core body temperature extraction. The system has been designed as a close-proximity sensor to detect thermal emissions radiated from deep inside the human body. The radiometer uses a cavity-backed slot antenna (CBSA) designed to account for performance degradation which occurs in the near field of the human body. Tissue-simulating
Quenton Bonds; John Gerig; Thomas M. Weller; Paul Herzig
High speed radiometric measurements of IED detonation fireballs
NASA Astrophysics Data System (ADS)
Continuum emission is predominant in fireball spectral phenomena and in some demonstrated cases, fine detail in the temporal evolution of infrared spectral emissions can be used to estimate size and chemical composition of the device. Recent work indicates that a few narrow radiometric bands may reveal forensic information needed for the explosive discrimination and classification problem, representing an essential step in moving from "laboratory" measurements to a rugged, fieldable system. To explore phenomena not observable in previous experiments, a high speed (10?s resolution) radiometer with four channels spanning the infrared spectrum observed the detonation of nine home made explosive (HME) devices in the < 100lb class. Radiometric measurements indicate that the detonation fireball is well approximated as a single temperature blackbody at early time (0 < t <~ 3ms). The effective radius obtained from absolute intensity indicates fireball growth at supersonic velocity during this time. Peak fireball temperatures during this initial detonation range between 3000.3500K. The initial temperature decay with time (t <~ 10ms) can be described by a simple phenomenological model based on radiative cooling. After this rapid decay, temperature exhibits a small, steady increase with time (10 <~ t <~ 50ms) and peaking somewhere between 1000.1500K-likely the result of post-detonation combustion-before subsequent cooling back to ambient conditions . Radius derived from radiometric measurements can be described well (R2 > 0.98) using blast model functional forms, suggesting that energy release could be estimated from single-pixel radiometric detectors. Comparison of radiometer-derived fireball size with FLIR infrared imagery indicate the Planckian intensity size estimates are about a factor of two smaller than the physical extent of the fireball.
Spidell, Matthew T.; Gordon, J. Motos; Pitz, Jeremey; Gross, Kevin C.; Perram, Glen P.
LANDSAT-4 multispectral scanner (MSS) subsystem radiometric characterization
NASA Technical Reports Server (NTRS)
The multispectral band scanner (mass) and its spectral characteristics are described and methods are given for relating video digital levels on computer compatible tapes to radiance into the sensor. Topics covered include prelaunch calibration procedures and postlaunch radiometric processng. Examples of current data resident on the MSS image processing system are included. The MSS on LANDSAT 4 is compared with the scanners on earlier LANDSAT satellites.
Alford, W. (editor); Barker, J. (editor); Clark, B. P.; Dasgupta, R.
Radiometric calibration of the three-channel imaging polarimeter
NASA Astrophysics Data System (ADS)
Radiometric calibration is of critical importance for information quantification of imaging polarimeters. In this paper, an integral sphere which had been traced to cryogenic radiometer was used as transfer standard in our calibration facility. The linearity, uniformity, stability of our imaging polarimeter were calibrated. The combined uncertainty in the responsivity of an imaging polarimeter was about 7.5%. At last, technical proposals of reducing uncertainty budget were briefly discussed.
Zhang, Lei; Liu, Xiao-cheng; Yin, Cheng-liang; Luo, Xiao-lin; Duan, Chang-pu
Physical aspects of radiometric monitoring of air pollution
NASA Astrophysics Data System (ADS)
We analyze the main physical approximations of radiometric monitoring of minor gas components (MGC) in the atmosphere in the millimeter wave range. Theoretical spectra of atmospheric obsorptions are obtained for the lower layers allowing for some MGCs for contents exceeding one-time limiting permissible concentrations. Conclusions are drawn on the diagnostic conditions for some MGCs using their thermal radio emission in the microwave range.
Naumov, A. P.; Osharina, N. N.
Comparison of Sm-Nd and UPb dating methods in rare-earth and associated minerals from pegmatites
The study was undertaken to explore the applicability of the newly developed Sm-Nd dating method to rare-earth minerals which exhibit relatively large rare-earth-element fractionations and their geological environments, and to compare the results of this dating system with those of the well-developed U-Pb system. A procedure was developed for the chemical separations for radiometric chronology. The Sm-Nd data of the
Laboratory-Based BRDF Calibration of Radiometric Tarps
NASA Technical Reports Server (NTRS)
The current study provides the remote sensing community with important high accuracy laboratory-based BRDF calibration of radiometric tarps. The results illustrate the dependence of tarps' weft and warp threads orientation on BRDF. The study was done at incident angles of 0deg, 10deg, and 30deg; scatter zenith angles from 0deg to 60deg, and scatter azimuth angles of 0deg, 45deg, 90deg, 135deg, and 180deg. The wavelengths were 485nm, 550nm, 633nm and 800nm. The dependence is well defined at all measurement geometries and wavelengths. It can be as high as 8% at 0deg incident angle and 2% at 30deg incident angle. The fitted BRDF data show a very small discrepancy from the measured ones. New data on the forward and backscatter properties of radiometric tarps is reported. The backward scatter is well pronounced for the white samples. The black sample has well pronounced forward scatter. The BRDF characterization of radiometric tarps can be successfully extended to other structured surface fabric samples. The results are NIST traceable.
Georgiev, Georgi T.; Butler, James J.
Preliminary radiometric calibration assessment of ALOS AVNIR-2
This paper summarizes the activities carried out in the frame of the data quality activities of the Advanced Visible and Near Infrared Radiometer type 2 (AVNIR-2) sensor onboard the Advanced Land Observing Satellite (ALOS). Assessment of the radiometric calibration of the AVNIR-2 multi-spectral imager is achieved via three intercomparisons to currently flying sensors over the Libyan desert, during the first year of operation. AU three methodologies indicate a slight underestimation of AVNIR-2 in band 1 by 4 to 7% with respect to other sensors radiometric scale. Band 2 does not show any obvious bias. Results for band 3 are affected by saturation due to inappropriate gain setting. Two methodologies indicate no significant bias in band 4. Preliminary results indicate possible degradations of the AVNIR-2 channels, which, when modeled as an exponentially decreasing functions, have time constants of respectively 13.2 %.year-1, 8.8%.year-1 and 0.1%.year-1 in band 1, 2 and 4 (with respect to the radiometric scale of the MEdium Resolution Imaging Spectrometer, MERIS). Longer time series of AVNIR-2 data are needed to draw final conclusions. ?? 2007 IEEE.
Bouvet, M.; Goryl, P.; Chander, G.; Santer, R.; Saunier, S.
A preliminary analysis of LANDSAT-4 Thematic Mapper radiometric performance
NASA Technical Reports Server (NTRS)
The NASA raw (BT) product, the radiometrically corrected (AT) product, and the radiometrically and geometrically corrected (PT) product of a TM scene were analyzed examine the frequency distribution of the digital data; the statistical correlation between the bands; and the variability between the detectors within a band. The analyses were performed on a series of image subsets from the full scence. Results are presented from one 1024 c 1024 pixel subset of Realfoot Lake, Tennessee which displayed a representative range of ground conditions and cover types occurring within the full frame image. From this cursory examination of one of the first seven channel TM data sets, it would appear that the radiometric performance of the system is most satisfactory and largely meets pre-launch specifications. Problems were noted with Band 5 Detector 3 and Band 2 Detector 4. Differences were observed between forward and reverse scan detector responses both for the BT and AT products. No systematic variations were observed between odd and even detectors.
Justice, C.; Fusco, L.; Mehl, W.
On the estimation of snow depth from microwave radiometric measurements
NASA Technical Reports Server (NTRS)
Multiple-channel microwave radiometric measurements made over Alaska at aircraft (near 90 and 183 GHz) and satellite (at 37 and 85 GHz) altitudes are used to study the effect of atmospheric absorption on the estimation of snow depth. The estimation is based on the radiative transfer calculations using an early theoretical model of Mie scattering of single-size particles. It is shown that the radiometric correction for the effect of atmospheric absorption is important even at 37 GHz for a reliable estimation of snow depth. Under a dry atmosphere and based on single-frequency radiometric measurements, the underestimation of snow depth could amount to 50 percent at 85 GHz and 20-30 percent at 37 GHz if the effect of atmospheric absorption is not taken into account. The snow depths estimated from the 90-GHz aircraft and 85-GHz satellite measurements are found to be in reasonable agreement. However, there is a discrepancy in the snow depths estimated from the 37-GHz (at both vertical and horizontal polarizations) and 85-GHz satellite measurements.
Wang, James R.; Chang, Alfred T. C.; Sharma, Awdhesh K.
NSDL National Science Digital Library
This on-line version of StarDate astronomy magazine provides current viewing information, a sky almanac, Moon phase calculator, sunrise and sunset calculator, planet viewing information, and meteor shower updates. News and Features contains information and details on the latest findings and research in the field of astronomy. Resources contains an image gallery, an astroglossary, and solar system, constellation, and star guides. The Radio section contains past radio programs by date, or searchable by subject. Also available are an archive database of past StarDate articles, and a teacher's section with ideas for teaching astronomy concepts in the classroom.
NSDL National Science Digital Library
First, the USGS summarizes the use of tritium and helium-3 for dating geologically young groundwater (1). Researchers can find the conditions needed to solve the helium isotope mass balance as well as equations and corrections needed to obtain the age of water. The second website, provided by the Rosenstiel School of Marine and Atmospheric Sciences, discusses the presence of tritium and helium isotopes in the oceans (2). Users can find out about the Noble Gas Isotope Lab's research projects including the _Mantle 3He Distribution and Deep Circulation in the Indian Ocean_. Next, the University of Ottawa offers equations for helium and tritium concentrations and decay (3). Visitors can also learn how solubility of noble gases is affected by temperature. Fourth, the University of Waterloo describes the characteristics of the hydrogen radioisotope, tritium (4). The website explains how tritium was discovered through the work of Lord Rutherford, Sir John, Ernest Lawrence, Luis Alvarex, Willard Libby, and others. Next, the University of T'bingen furnishes a pdf file dealing with numerous dating techniques including fission track, radio carbon, and thermoluminescence dating (5). Beginning on page nine, individuals can learn about tritium formation and decay as well as its use in dating ground water. At the sixth website, the USGS describes the characteristics of the stable isotopes of helium (6). Visitors can discover how 3He is used to date geologically young ground water, whereas 4He is used to date older ground water. The seventh website, created by SAHRA (Sustainability of semi-Arid Hydrology and Riparian Areas) at the University of Arizona, illustrates the effectiveness of isotope hydrology in "understanding fundamental physical, chemical, biological, and climate forcing processes occurring in a watershed" (7). Along with the discussion of the fundamentals of age dating and sources of isotopes, visitors can learn the advantages to using tritium for water samples collected in the field. Lastly, the Victoria University of Manchester introduces its research using noble gas isotopes to better understand earth systems (8). Visitors can discover the decay rates of tritium to 3He and the rates of accumulation of 4He in older groundwater as well as many applications of dating water.
Dating Impacts: New Constraints from 40Ar39Ar Analyses of Shocked Chondrites
Since the beginning of crater dating it has been a matter of debate which chronometer should be applied on which kind of impact-metamorphic rock to obtain the true age of a crater. The transition of even a high pressure shock wave in itself appears to be insufficient to fully reset radiometric isotope systems although the K-Ar system suffers partial 40Ar
J. Kunz; M. Falter; D. Stoffler; M. Trieloff; E. K. Jessberger
Scientists from Brookhaven National Laboratory, the University of Arizona, and the Smithsonian Institution used carbon-dating technology to determine the age of a controversial parchment that might be the first-ever map of North America.
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Microwave and Millimeter-Wave Radiometric Studies of Temperature, Water Vapor and Clouds
The importance of accurate measurements of column amounts of water vapor and cloud liquid has been well documented by scientists within the Atmospheric Radiation Measurement (ARM) Program. At the North Slope of Alaska (NSA), both microwave radiometers (MWR) and the MWRProfiler (MWRP), been used operationally by ARM for passive retrievals of the quantities: Precipitable Water Vapor (PWV) and Liquid Water Path (LWP). However, it has been convincingly shown that these instruments are inadequate to measure low amounts of PWV and LWP. In the case of water vapor, this is especially important during the Arctic winter, when PWV is frequently less than 2 mm. For low amounts of LWP (< 50 g/m{sup 2}), the MWR and MWRP retrievals have an accuracy that is also not acceptable. To address some of these needs, in March-April 2004, NOAA and ARM conducted the NSA Arctic Winter Radiometric Experiment - Water Vapor Intensive Operational Period at the ARM NSA/Adjacent Arctic Ocean (NSA/AAO) site. After this experiment, the radiometer group at NOAA moved to the Center for Environmental Technology (CET) of the Department of Electrical and Computer Engineering of the University of Colorado at Boulder. During this 2004 experiment, a total of 220 radiosondes were launched, and radiometric data from 22.235 to 380 GHz were obtained. Primary instruments included the ARM MWR and MWRP, a Global Positioning System (GPS), as well as the CET Ground-based Scanning Radiometer (GSR). We have analyzed data from these instruments to answer several questions of importance to ARM, including: (a) techniques for improved water vapor measurements; (b) improved calibration techniques during cloudy conditions; (c) the spectral response of radiometers to a variety of conditions: clear, liquid, ice, and mixed phase clouds; and (d) forward modeling of microwave and millimeter wave brightness temperatures from 22 to 380 GHz. Many of these results have been published in the open literature. During the third year of this contract, we participated in another ARM-sponsored experiment at the NSA during February-March 2007. This experiment is called the Radiative Heating in Underexplored Bands Campaign (RHUBC) and the GSR was operated successfully for the duration of the campaign. One of the principal goals of the experiment was to provide retrievals of water vapor during PWV amounts less than 2 mm and to compare GSR data with ARM radiometers and radiosondes. A secondary goal was to compare the radiometric response of the microwave and millimeter wavelength radiometers to water and ice clouds. In this final report, we will include the separate progress reports for each of the three years of the project and follow with a section on major accomplishments of the project.
Westwater, Edgeworth
Retrievals of Column Water Vapor Using Millimeter-Wave Radiometric Measurements
NASA Technical Reports Server (NTRS)
Water vapor is one of the most important atmospheric constituents that has a critical impact on cloud formation (ice or liquid). It is also a source that needs to be accounted for in remote measurements of surface parameters. In the high-latitude regions, e.g., Antarctica, monitoring of the state of water vapor and its transport into and out of these regions is important towards our understanding the state of balance of ice sheets and its effect on the global sea level. The technique of retrieving low amount of column water vapor using the millimeter-wave radiometric measurements, as presented in this paper, will be very useful for these regions, especially during winter times when the atmosphere is relatively dry.
Wang, J. R.; Racette, P.; Triesky, M. E.; Manning, W.; Hildebrand, Peter H. (Technical Monitor)
NASA Astrophysics Data System (ADS)
Although the age determination of plutonium is and has been a pillar of nuclear forensic investigations for many years, additional research in the field of plutonium age dating is still needed and leads to new insights as the present work shows: Plutonium is commonly dated with the help of the 241Pu/241Am chronometer using gamma spectrometry; in fewer cases the 240Pu/236U chronometer has been used. The age dating results of the 239Pu/235U chronometer and the 238Pu/234U chronometer are scarcely applied in addition to the 240Pu/236U chronometer, although their results can be obtained simultaneously from the same mass spectrometric experiments as the age dating result of latter. The reliability of the result can be tested when the results of different chronometers are compared. The 242Pu/238U chronometer is normally not evaluated at all due to its sensitivity to contamination with natural uranium. This apparent 'weakness' that renders the age dating results of the 242Pu/238U chronometer almost useless for nuclear forensic investigations, however turns out to be an advantage looked at from another perspective: the 242Pu/238U chronometer can be utilized as an indicator for uranium contamination of plutonium samples and even help to identify the nature of this contamination. To illustrate this the age dating results of all four Pu/U clocks mentioned above are discussed for one plutonium sample (NBS 946) that shows no signs of uranium contamination and for three additional plutonium samples. In case the 242Pu/238U chronometer results in an older 'age' than the other Pu/U chronometers, contamination with either a small amount of enriched or with natural or depleted uranium is for example possible. If the age dating result of the 239Pu/235U chronometer is also influenced the nature of the contamination can be identified; enriched uranium is in this latter case a likely cause for the missmatch of the age dating results of the Pu/U chronometers.
Sturm, Monika; Richter, Stephan; Aregbe, Yetunde; Wellum, Roger; Mayer, Klaus; Prohaska, Thomas
Radiometric calibration of the Landsat MSS sensor series
Multispectral remote sensing of the Earth using Landsat sensors was ushered on July 23, 1972, with the launch of Landsat-1. Following that success, four more Landsat satellites were launched, and each of these carried the Multispectral Scanner System (MSS). These five sensors provided the only consistent multispectral space-based imagery of the Earth's surface from 1972 to 1982. This work focuses on developing both a consistent and absolute radiometric calibration of this sensor system. Cross-calibration of the MSS was performed through the use of pseudoinvariant calibration sites (PICSs). Since these sites have been shown to be stable for long periods of time, changes in MSS observations of these sites were attributed to changes in the sensors themselves. In addition, simultaneous data collections were available for some MSS sensor pairs, and these were also used for cross-calibration. Results indicated substantial differences existed between instruments, up to 16%, and these were reduced to 5% or less across all MSS sensors and bands. Lastly, this paper takes the calibration through the final step and places the MSS sensors on an absolute radiometric scale. The methodology used to achieve this was based on simultaneous data collections by the Landsat-5 MSS and Thematic Mapper (TM) instruments. Through analysis of image data from a PICS location and through compensating for the spectral differences between the two instruments, the Landsat-5 MSS sensor was placed on an absolute radiometric scale based on the Landsat-5 TM sensor. Uncertainties associated with this calibration are considered to be less than 5%.
Helder, Dennis L.; Karki, Sadhana; Bhatt, Rajendra; Micijevik, Esad; Aaron, David; Jasinski, Benjamin
BOREAS TE-18, 30-m, Radiometrically Rectified Landsat TM Imagery
NASA Technical Reports Server (NTRS)
The BOREAS TE-18 team used a radiometric rectification process to produce standardized DN values for a series of Landsat TM images of the BOREAS SSA and NSA in order to compare images that were collected under different atmospheric conditions. The images for each study area were referenced to an image that had very clear atmospheric qualities. The reference image for the SSA was collected on 02-Sep-1994, while the reference image for the NSA was collected on 21-Jun-1995. the 23 rectified images cover the period of 07-Jul-1985 to 18 Sep-1994 in the SSA and from 22-Jun-1984 to 09-Jun-1994 in the NSA. Each of the reference scenes had coincident atmospheric optical thickness measurements made by RSS-11. The radiometric rectification process is described in more detail by Hall et al. (199 1). The original Landsat TM data were received from CCRS for use in the BOREAS project. The data are stored in binary image-format files. Due to the nature of the radiometric rectification process and copyright issues, these full-resolution images may not be publicly distributed. However, a spatially degraded 60-m resolution version of the images is available on the BOREAS CD-ROM series. See Sections 15 and 16 for information about how to possibly acquire the full resolution data. Information about the full-resolution images is provided in an inventory listing on the CD-ROMs. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Activity Archive Center (DAAC).
Hall, Forrest G. (Editor); Knapp, David
An approach to the radiometric aerotriangulation of photogrammetric images
NASA Astrophysics Data System (ADS)
Harnessing the radiometric information provided by photogrammetric flights could be useful in increasing the thematic applications of aerial images. The aim of this paper is to improve relative and absolute homogenization in aerial images by applying atmospheric correction and treatment of bidirectional effects. We propose combining remote sensing methodologies based on radiative transfer models and photogrammetry models, taking into account the three-dimensional geometry of the images (external orientation and Digital Elevation Model). The photogrammetric flight was done with a Z/I Digital Mapping Camera (DMC) with a Ground Sample Distance (GSD) of 45 cm. Spectral field data were acquired by defining radiometric control points in order to apply atmospheric correction models, obtaining calibration parameters from the camera and surface reflectance images. Kernel-driven models were applied to correct the anisotropy caused by the bidirectional reflectance distribution function (BRDF) of surfaces viewed under large observation angles with constant illumination, using the overlapping area between images and the establishment of radiometric tie points. Two case studies were used: 8-bit images with applied Lookup Tables (LUTs) resulting from the conventional photogrammetric workflow for BRDF studies and original 12-bit images (Low Resolution Color, LRC) for the correction of atmospheric and bidirectional effects. The proposed methodology shows promising results in the different phases of the process. The geometric kernel that shows the best performance is the Lidense kernel. The homogenization factor in 8-bit images ranged from 6% to 25% relative to the range of digital numbers (0-255), and from 18% to 35% relative to levels of reflectance (0-100) in the 12-bit images, representing a relative improvement of approximately 1-30%, depending on the band analyzed.
Hern�ndez L�pez, David; Felipe Garc�a, Beatriz; Gonz�lez Piqueras, Jos�; Alc�zar, Guillermo Villa
In-flight absolute radiometric calibration of the thematic mapper
NASA Technical Reports Server (NTRS)
The TM multispectral scanner system was calibrated in an absolute manner before launch. To determine the temporal changes of the absolute radiometric calibration of the entire system, spectroradiometric measurements of the ground and the atmosphere were made simultaneously with TM collections over White Sands, New Mexico. By entering the measured values in an atmospheric radiative transfer program, the radiance levels of the in four of the spectral bands of the TM were determined. Tables show values for the reflectance of snow at White Sands measured by a modular 8 channel radiometer, and values for exoatmospheric irradiance within the TM passbands, calculated for the Earth-Sun distance using a solar radiometer.
Castle, K. R.; Holm, R. G.; Kastner, C. J.; Palmer, J. M.; Slater, P. N.; Dinguirard, M.; Ezra, C. E.; Jackson, R. D.; Savage, R. K.
Atmospheric corrections to satellite radiometric data over rugged terrain
NASA Technical Reports Server (NTRS)
Radiometric measurements from satellites in the solar portion of the electromagnetic spectrum can be converted to measurements of surface exitance. Over rugged terrain, the satellite image must be precisely registered to a terrain data set. For small areas a first-order polynomial interpolation scheme is generally satisfactory for the geometric rectification. If there are saturated pixels, a nearest-neighbor procedure is used for the interpolated satellite radiance numbers; otherwise a cubic-convolution algorithm is used. Path radiance and path transmittance are calculated with a simple spectral model, which requires an estimate of the water vapor and aerosol content of the atmosphere.
Dozier, J.; Frew, J.
A review of some radiometric calibration problems and methods
NASA Technical Reports Server (NTRS)
The in-flight radiometric calibration instrumentation and procedures of the Landsat Thematic Mapper and the high-resolution visible-range instruments of SPOT are illustrated with drawings and diagrams, characterized, and compared. Problems encountered in the laboratory calibration process, minimizing the temporal instability of the systems, identifying anomalies in the electronics in flight, and rechecking the calibration are examined, and it is pointed out that the stability of the calibration systems is less than that of the instruments themselves. The use of carefully measured ground-site data and atmospheric parameters in combination with radiative-transfer models for periodic calibration is recommended.
Slater, P. N.
ESR (electron spin resonance) dating method has been used to determine the ages of quaternary events. When a mineral receives natural radiation, a part of paired electrons in quartz are ionized, and are trapped by lattice defects and impurties as unpaired electrons. The amount of unpaired electrons increases with time. The ESR age is obtained by dividing the total dose
A. Shimada; S. Toyoda; H. Takagi; K. Arita
ERIC Educational Resources Information Center
Presents activities to cultivate the tendency to see special qualities in numbers that can be played on certain calendar days. Includes games on the constant of the day, Fibonacci and golden ratio dates, primes, powers, December 25, and the day of the year. (ASK)
Zerger, Monte J.
Calcium-41 concentration in terrestrial materials: prospects for dating of pleistocene samples
Calcium-41 bas been suggested as a new tool for radiometric dating in the range of 10/sup 5/ to 10/sup 6/ years. The concentration of cosmogenic calcium-41 in natural samples of terrestrial origin has now been determined by high-sensitivity accelerator mass spectrometry after pre-enrichment in calcium-41 with an isotope separator. Ratios of calcium-41 to total calcium between 2 x 10/sup -14/ and 3 x 10/sup -15/ were measured for samples of contemporary bovine bone and from limestone deposits. Some prospects for the use of calcium-41 for dating Middle and Late Pleistocene bone and for other geophysical applications are discussed.
Henning, W.; Bell, W.A.; Billquist, P.J.; Glagola, B.G.; Kutschera, W.; Liu, Z.; Lucas, H.F.; Paul, M.; Rehm, K.E.; Yntema, J.L.
ERIC Educational Resources Information Center
This poster presentation addresses the issue of date rape, specifically in the college environment. Highlighted are date rape statistics, demographics, and date rape drugs. Also discussed are date rape warnings and prevention strategies. It is concluded that college and university administrators must place the issue of date rape and acquaintance�
Presley, Cara; Watson, Jennifer; Williams, Audrey R.
A radiometric assay for bacterial growth detection and quantitative antibiotic testing
Buddemeyer's two-compartment radiometric assay for bacterial growth using respired C-14 carbon dioxide promised major advantages over other available methods, but limitations of the technique have restricted its application. Through a systemic study of relevant physical and chemical factors the authors sought to improve the assay for earlier detection of bacterial growth and to extend its use to measurement of antibiotic drug susceptibility and potency. A 35-fold improvement in count rate response was achieved by a) reversing growth and detector chambers to permit rigorous agitation, b) increasing NaOH quantity and using a supersaturated PPO solution, and c) adding detergent to stabilize NaOH-PPO contact. Bacterial growth may be detected as early as 1/2 hour after inoculation. For rapidly growing bacteria the growth rate constant is defined as the slope of the growth curve (log count rate vs. time). The validity of the growth behavior was verified by measuring growth at several inoculum sizes over 3 orders of magnitude using standard strains of S. aureus and E. coli. The growth rate constant proved to be independent of inoculum size. To test the merit of the system as an antibiotic assay, E. coli were exposed to doses of spectinomycin hydrochloride in the range which yielded a nonlinear dose-response relation by a turbidity assay. The test, however, showed a linear relation between growth rate constant and antibiotic dose. The results clearly indicate the radiometric growth rate assay to be a rapid, valid and objective assay for bacterial growth and antibiotic sensitivity.
Boonkitticharoen, V.; Kirchner, P.T.; Ehrhardt, J.C.
Blood culture cross contamination associated with a radiometric analyzer
During a 9-day period in August 1980 in a New Jersey hospital, three pairs of consecutively numbered blood cultures from different patients were identified as positive for the same organism, for each pair, both cultures were positive in the same atmosphere, both organisms had the same sensitivities, and the second of each pair grew at least 2 days after the first and was the only positive blood culture obtained from the patient. When the hospital laboratory discontinued use of its radiometric culture analyzer for 15 days, no more consecutive pairs of positive cultures occurred. Subsequent use of the machine for 9 days with a new power unit but the original circuit boards resulted in one more similar consecutive pair (Staphylococcus epidermidis). After replacement of the entire power unit, there were no further such pairs. Examination of the machine by the manufacturer revealed a defective circuit board which resulted in inadequate needle sterilization. Laboratories which utilize radiometric analyzers should be aware of the potential for cross contamination. Recognition of such events requires alert microbiologists and infection control practitioners and a record system in the bacteriology laboratory designed to identify such clusters.
Griffin, M.R.; Miller, A.D.; Davis, A.C.
Investigation of radiometric properties of the LANDSAT-4 multispectral scanner
NASA Technical Reports Server (NTRS)
The radiometric data quality of the LANDSAT 4 multispectral scanner (MSS) was examined using several LANDSAT 4 frames. It was found that LANDSAT 4 MSS produces high-quality data of the caliber experienced with previous LANDSATS. For example, the detector equalization procedure worked well, leaving a residual banding effect of about 0.3 digital counts RMS, close to the theoretical minimum value of quantization error. Nevertheless, artifacts of the data were found, two of which were not experienced in previous MSS data. A low-level coherent noise effect was observed in all bands, with a magnitude of about 0.5 digital counts and a frequency of approximately 28 KHz (representing a wavelength of about 3.6 pixels); a substantial increase in processing complexity would be required to reduce this artifact in the data. Also, a substantial scan-length variation (of up to six pixels) was noted in MSS data when the TM sensor was operating; the LANDSAT 4 correction algorithms being applied routinely by the EROS Data Center to produce a p-type data should remove most of this variation. Between-satellite calibrations were examined in paired LANDSAT 3 and LANDSAT 4 MSS data sets, which were closely matched in acquisition time and place. Radiometric comparisons showed that all bands were highly linear in digital counts, and a well-determined linear transformation between the MSS's was established.
Malila, W. A. (principal investigator); Rice, D. P.
In-flight radiometric calibration of AVIRIS in 1994
NASA Technical Reports Server (NTRS)
The AVIRIS sensor must be calibrated at the time it measures spectra from the ER-2 airborne platform in order to achieve research and application objectives that are both quantitative and physically based. However, the operational environment inside the Q-bay of the ER-2 at 20 km altitude differs from that in the AVIRIS laboratory with respect to temperature, pressure, vibration, and high-frequency electromagnetic fields. Experiments at surface calibration targets are used in each flight season to confirm the accuracy of AVIRIS in-flight radiometric calibrations. For these experiments, the MODTRAN radiative transfer code is constrained by using in situ measurements to independently predict the upwelling spectral radiance arriving at AVIRIS for a specific calibration target. AVIRIS calibration is validated in flight by comparing the MODTRAN-predicted radiance to the laboratory-calibrated radiance measured by the AVIRIS sensor for the same time over the calibration target. We present radiometric calibration results for the AVIRIS in-flight calibration experiment held at the beginning of the 1994 flight season.
Green, Robert O.; Conel, James E.; Helmlinger, Mark; Vandenbosch, Jeannette; Hajek, Pavel
Radiometric measurement of differential metabolism of fatty acid by mycobacteria
An assay system has been developed based on automated radiometric quantification of /sup 14/CO2 produced through oxidation of (1-/sup 14/C) fatty acids by mycobacteria. Two stains of M. tuberculosis (H37Rv and Erdman) and one of M. bovis (BCG) in 7H9 medium (ADC) with 1.0 microCi of one of the fatty acids (butyric, hexanoic, octanoic, decanoic, lauric, myristic, palmitic, stearic, oleic, linoleic and linolenic) were studied. Results previously published on M. lepraemurium (Hawaiian) were also included for comparison. Both strains of M. tuberculosis had maximum /sup 14/CO2 production from hexanoic acid. Oxidation of butyric and avid oxidation of lauric acids were also found with the H37Rv strain but not with Erdman. In contrast, /sup 14/CO2 production by M. bovis was greatest from lauric and somewhat less from decanoic acid. M. lepraemurium showed increasing oxidation rates from myristic, decanoic and lauric acids. Assimilation studies of M. tuberculosis H37Rv confirmed that most of the oxidized substrates were converted into by-products with no change in those from which no oxidation was found. These data suggest that the radiometric measurement of differential fatty acid metabolism may provide a basis of strain identification of the genus Mycobacterium.
Camargo, E.E.; Kertcher, J.A.; Larson, S.M.; Tepper, B.S.; Wagner, H.N. Jr.
Accurate Radiometric Calibration using Mechanically-Shuttered CCD Systems
NASA Astrophysics Data System (ADS)
Acquiring accurate radiometric measurements is an essential part of characterizing non-resolvable satellites. For instance, temporal photometric signatures provide information on characteristic size, reflectance, and stability, spin rate, etc., and with more detailed analysis, shape and attitude. Multi-color photometric measurements provide information on material composition and the effects of space weathering. Thermal infrared radiometry provides gray-body temperatures and emissivity properties. Many of these methods rely on accurate radiometric calibration. For CCD systems, the calibration process generally entails removing bias and dark signals from the raw frames, dividing by a flat-field frame to account for non-uniformities, and applying a sensitivity factor to convert the remaining signal into photon-flux or energy-flux units. However, when using mechanically-shuttered camera systems, another effect must be accounted for to obtain accurately calibrated data: the finite time required for the mechanical shutter to open and close. Measurements for both two-bladed and iris mechanical shutters indicate that neglecting this effect can lead to calibration errors of 10% or more in short-duration exposures. We present methods for measuring this effect, either in a laboratory setting or with the instrument mounted on a telescope, and the additional steps required to calibrate CCD data.
Hall, D.; Liang, D.
Empirical radiometric correction of optical remote sensing imagery
NASA Astrophysics Data System (ADS)
We propose an empirical radiometric correction method for the effects, such as atmospheric effects and anisotropic reflection of the surface, in optical remote sensing data. These distortions are sensor viewing (scanning) angle dependent, thus they can be significant for data received from airborne sensors due to their wide field of view. The procedure is based solely on the digital image data and consists of several steps. First, the initial image region near nadir (minimal distortions) is clustered by an extended k-means algorithm, which automatically detects the clusters (surface types) in an image. Then, for each cluster an average line profile is calculated. These profiles (initially defined in a middle part of an image line) are extrapolated to the whole line of an image by a polynomial approximation. Finally, from these polynomial functions the linear regression over all clusters is build using the radiative transfer equation, which allows the radiometric correction for each viewing angle in an image relative to the reference angle, usually nadir. The procedure is iterative, that is the correction is first performed for a narrow part around the initial region. Then the procedure is initialized with this newly corrected image region and repeated until the whole image is corrected. The experiments for data acquired by airborne multispectral scanner DAEDALUS AADS 1268 ATM show the effectiveness of the proposed method especially for the mosaicking and classification applications.
Palubinskas, Gintautas; Mueller, Rupert M.; Reinartz, Peter H.
A preliminary analysis of LANDSAT-4 Thematic Mapper radiometric performance
NASA Technical Reports Server (NTRS)
Analysis was performed to characterize the radiometry of three Thematic Mapper (TM) digital products of a scene of Arkansas. The three digital products examined were the NASA raw (BT) product, the radiometrically corrected (AT) product and the radiometrically and geometrically corrected (PT) product. The frequency distribution of the digital data; the statistical correlation between the bands; and the variability between the detectors within a band were examined on a series of image subsets from the full scene. The results are presented from one 1024 x 1024 pixel subset of Realfoot Lake, Tennessee which displayed a representative range of ground conditions and cover types occurring within the full frame image. Bands 1, 2 and 5 of the sample area are presented. The subsets were extracted from the three digital data products to cover the same geographic area. This analysis provides the first step towards a full appraisal of the TM radiometry being performed as part of the ESA/CEC contribution to the NASA/LIDQA program.
Justice, C.; Fusco, L.; Mehl, W.
Regression of in-water radiometric profile data.
This study addresses the regression of in-water radiometric profile data with the objective of investigating solutions to minimize uncertainties of derived products like subsurface radiance and irradiance (L(u0) and E(d0)) and diffuse attenuation coefficients. Analyses are conducted using radiometric profiles generated through Monte Carlo simulations and field measurements. A nonlinear NL approach is presented as an alternative to the standard linear method LN. Results indicate that the LN method, relying on log-transformed data, tends to underestimate regression results with respect to NL operating on non-transformed data. The log-transformation is thus identified as the source of biases in data products. Observed differences between LN and NL regression results for L(u0) are of the order of 1-2%, that is well below the target uncertainty for data products from in situ measurements (i.e., 5%). For E(d0), instead, differences can easily exceed 5% as a result of more pronounced light focusing and defocusing effects due to wave perturbations. This work also remarks the importance of applying the multi-cast measurement scheme as a mean to increase the precision of data products. PMID:24514288
D'Alimonte, Davide; Shybanov, Eugeny B; Zibordi, Giuseppe; Kajiyama, Tamito
Branching Ratios for The Radiometric Calibration of EUNIS-2012
NASA Technical Reports Server (NTRS)
The Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS) sounding rocket instrument is a two-channel imaging spectrograph that observes the solar corona and transition region with high spectral resolution and a rapid cadence made possible by unprecedented sensitivity. The upcoming flight will incorporate a new wavelength channel covering the range 524-630 Angstroms, the previously-flown 300-370 Angstroms channel, and the first flight demonstration of cooled active pixel sensor (APS) arrays. The new 524-630 Angstrom channel incorporates a Toroidal Varied Line Space (TVLS) grating coated with B4C/Ir, providing broad spectral coverage and a wide temperature range of 0.025 to 10 MK. Absolute radiometric calibration of the two channels is being performed using a hollow cathode discharge lamp and NIST-calibrated AXUV-100G photodiode. Laboratory observations of He I 584 Angstroms and He II 304 Angstroms provide absolute radiometric calibrations of the two channels at those two respective wavelengths by using the AXUV photodiode as a transfer standard. The spectral responsivity is being determined by observing line pairs with a common upper state in the spectra of Ne I-III and Ar II-III. Calculations of A-values for the observed branching ratios are in progress.
Daw, Adrian N.; Bhatia, A. K.; Rabin, Douglas M.
Absolute ages from crater statistics: Using radiometric ages of Martian samples for determining the Martian cratering chronology
NASA Technical Reports Server (NTRS)
In the absence of dates derived from rock samples, impact crater frequencies are commonly used to date Martian surface units. All models for absolute dating rely on the lunar cratering chronology and on the validity of its extrapolation to Martian conditions. Starting from somewhat different lunar chronologies, rather different Martian cratering chronologies are found in the literature. Currently favored models are compared. The differences at old ages are significant, the differences at younger ages are considerable and give absolute ages for the same crater frequencies as different as a factor of 3. The total uncertainty could be much higher, though, since the ratio of lunar to Martian cratering rate which is of basic importance in the models is believed to be known no better than within a factor of 2. Thus, it is of crucial importance for understanding the the evolution of Mars and determining the sequence of events to establish an unambiguous Martian cratering chronology from crater statistics in combination with clean radiometric ages of returned Martian samples. For the dating goal, rocks should be as pristine as possible from a geologically simple area with a one-stage emplacement history of the local formation. A minimum of at least one highland site for old ages, two intermediate-aged sites, and one very young site is needed.
Neukum, G.
The Landsat Data Continuity Mission Operational Land Imager (OLI) Radiometric Calibration
NASA Technical Reports Server (NTRS)
The Operational Land Imager (OLI) on the Landsat Data Continuity Mission (LDCM) has a comprehensive radiometric characterization and calibration program beginning with the instrument design, and extending through integration and test, on-orbit operations and science data processing. Key instrument design features for radiometric calibration include dual solar diffusers and multi-lamped on-board calibrators. The radiometric calibration transfer procedure from NIST standards has multiple checks on the radiometric scale throughout the process and uses a heliostat as part of the transfer to orbit of the radiometric calibration. On-orbit lunar imaging will be used to track the instruments stability and side slither maneuvers will be used in addition to the solar diffuser to flat field across the thousands of detectors per band. A Calibration Validation Team is continuously involved in the process from design to operations. This team uses an Image Assessment System (IAS), part of the ground system to characterize and calibrate the on-orbit data.
Markham, Brian L.; Dabney, Philip W.; Murphy-Morris, Jeanine E.; Knight, Edward J.; Kvaran, Geir; Barsi, Julia A.
Accelerator radiocarbon dating of evidence for prehistoric horticulture in Illinois
With the development of direct detection radiocarbon dating, which uses an accelerator as part of a highly selective mass spectrometer, it is now possible to determine the age of milligram samples of organic materials1-5. One application of accelerator dating is in evaluating scanty, sometimes controversial evidence for early horticulture throughout the world. We have now used the technique to date
Nicholas Conard; David L. Asch; Nancy B. Asch; David Elmore; Harry Gove; Meyer Rubin; James A. Brown; Michael D. Wiant; Kenneth B. Farnsworth; Thomas G. Cook
From Romance to Rocket Science: Speed Dating in Higher Education
ERIC Educational Resources Information Center
This article is the first comprehensive review of speed dating in the tertiary sector. While speed dating has its origins as a networking technique to connect singles, it has only more recently made its way into the academy. Since 2005 universities world-wide have begun to adopt speed dating protocols as a tool for building research culture. An�
Muurlink, Olav; Poyatos Matas, Cristina
NSDL National Science Digital Library
This lesson shows students that age-dating rocks involves counting atoms and comparing the counts. Students use simulated rock samples, which show a highly magnified selection of 128 atoms, each sample with a different proportion of the atoms of two different elements: a parent radioisotope, and its daughter product. By counting the parent radioactive atoms and knowing the half-life of those atoms, students can figure the number of half-lives since the sample solidified, and therefore the age of the sample.
Lifetime and cyclicity of fluid venting at forearc mound structures determined by tephrostratigraphy and radiometric dating of authigenic carbonates
At convergent margins, fluids rise through the forearc in responseto consolidation of the upper plate and dewatering of the subductingplate, and produce various cold-seep-related featureson the seafloor (mud diapirs, mud mounds). At the Central Americanforearc, authigenic carbonates precipitated from rising fluidswithin such structures during active venting while typical mixed-mudsediments were ejected onto the surrounding seafloor where theybecame intercalated with normal
S. Kutterolf; V. Liebetrau; T. M�rz; A. Freundt; T. Hammerich; D. Garbe-Sch�nberg
Difficulties in interpreting fast mixing in the radiometric dating of sediments using 210 Pb and 137 Cs
210Pb geochronologies should be validated with independent tracers such as 137Cs. In the cases with constant 210Pb activity in the topmost sediments, the presence of a distinct 137Cs peak within the 210Pb plateau has been used as a definitive demonstration of acceleration (increase in the sedimentation rate in recent years) versus fast mixing. Nevertheless, some limitations can be identified in
J. M. Abril
The geological, paleobotanical and radiometric dating of Quaternary sediments in the region of Konin (eastern Great Poland Lowland)
A theoretical discussion of the availability of material, the emergence of the Pleistocene glacial series and the denudation occurring in the interglacial periods. The synthetic profile of the quaternary series in the region of Konin (eastern Great Poland) described in the light of geological, paleobotanical and luminescence studies.
Low-T eclogite in the Dabie terrane of China: petrological and isotopic constraints on fluid activity and radiometric dating
While extensive studies have demonstrated fluid release during subduction of oceanic crust, little attention has been paid to fluid activity during subduction and exhumation of continental crust. Abundant occurrence of quartz veins within eclogites in the Dabie-Sulu orogenic belt of China provides us with an opportunity to study the origin and role of vein-forming fluids with respect to heat and
Xu-Ping Li; Yong-Fei Zheng; Yuan-Bao Wu; Fukun Chen; Bing Gong; Yi-Liang Li
Lithostratigraphy, magnetostratigraphy, and radiometric dating of the Stanislaus Group, CA, and age of the Little Walker Caldera
The Miocene Stanislaus Group (Stanislaus, Calaveras, Tuolomne, Alpine and Mono counties, CA), composed of intercalated latite and quartz-latite (trachyandesite and trachyte\\/trachydacite) lavas and ignimbrites, provides an important marker for reconstructing the elevation history and tectonic development of the Sierra Nevada and Walker Lane. We present new Ar\\/Ar geochronology and magnetostratigraphy indicating that the Stanislaus Group was emplaced in two pulses:
Christopher J. Pluhar; Alan L. Deino; Nathan M. King; Cathy Busby; Brian P. Hausback; Tracy Wright; Collin Fischer
Parallel algorithms of relative radiometric correction for images of TH-1 satellite
NASA Astrophysics Data System (ADS)
The first generation of transitive stereo-metric satellites in China, TH-1 Satellite, is able to gain stereo images of three-line-array with resolution of 5 meters, multispectral images of 10 meters, and panchromatic high resolution images of 2 meters. The procedure between level 0 and level 1A of high resolution images is so called relative radiometric correction (RRC for short). The processing algorithm of high resolution images, with large volumes of data, is complicated and time consuming. In order to bring up the processing speed, people in industry commonly apply parallel processing techniques based on CPU or GPU. This article firstly introduces the whole process and each step of the algorithm - that is in application - of RRC for high resolution images in level 0; secondly, the theory and characteristics of MPI (Message Passing Interface) and OpenMP (Open Multi-Processing) parallel programming techniques is briefly described, as well as the superiority for parallel technique in image processing field; thirdly, aiming at each step of the algorithm in application and based on MPI+OpenMP hybrid paradigm, the parallelizability and the strategies of parallelism for three processing steps: Radiometric Correction, Splicing Pieces of TDICCD (Time Delay Integration Charge-Coupled Device) and Gray Level Adjustment among pieces of TDICCD are deeply discussed, and furthermore, deducts the theoretical acceleration rates of each step and the one of whole procedure, according to the processing styles and independence of calculation; for the step Splicing Pieces of TDICCD, two different strategies of parallelism are proposed, which are to be chosen with consideration of hardware capabilities; finally, series of experiments are carried out to verify the parallel algorithms by applying 2-meter panchromatic high resolution images of TH-1 Satellite, and the experimental results are analyzed. Strictly on the basis of former parallel algorithms, the programs in the experiments are written by parallelizing the serial version. Numerical results show that, the parallel algorithms proposed in this article can effectively bring up the processing speed of RRC for high resolution images of TH-1 Satellite, and, with its stable running and excellent image processing, meet the need of application. For three kinds of images, such as images with large amount of cloud, with little differences of ground features, and with good climate and plentiful ground features, the average acceleration rates could reach 2.484, 2.539 and 4.159 respectively.
Wang, Xiang; Zhang, Tingtao; Cheng, Jiasheng; Yang, Tao
Directional radiometric measurements of row-crop temperatures
NASA Technical Reports Server (NTRS)
The variability of directional sensor response for a cotton row crop in Phoenix, Arizona was measured for various solar zenith angles. The geometric structure of the canopy was described with regard to height, width, spacing, and shape of rows. In addition, radiometric temperature data were collected on four scene components: sunlit and shaded vegetation and sunlit and shaded soil. These data were used to test the predictions and assumptions of a modified version of the row crop model of Jackson et al. (1979), which predicts the thermal infrared response of a sensor as a function of sensor view angle, component temperature, and geometrical structure of the canopy. The field data showed sensor response differentials as great as 16.2 C when going from a zenith view angle of 0 deg to one of 80 deg normal to the row direction. The rms deviation between the predicted and measured sensor response for all measurement periods and view angles was 0.96 C.
Kimes, D. S.; Kirchner, J. A.
Radiometric calibration and SNR calculation of a SWIR imaging telescope
Radiometric calibration of an imaging telescope is usually made using a uniform illumination sphere in a laboratory. In this study, we used the open-sky images taken during bright day conditions to calibrate our telescope. We found a dark signal offset value and a linear response coefficient value for each pixel by using three different algorithms. Then we applied these coefficients to the taken images, and considerably lowered the image non-uniformity. Calibration can be repeated during the operation of telescope with an object that has better uniformity than open-sky. Also SNR (Signal to Noise Ratio) of each pixel was calculated from the open-sky images using the temporal mean and standard deviations. It is found that SNR is greater than 80 for all pixels even at low light levels.
Yilmaz, Ozgur; Turk, Fethi; Selimoglu, Ozgur [Tubitak Uzay (Space Technologies Research Institute) ODTU Campus 06531 Ankara (Turkey)
[In-flight absolute radiometric calibration of UAV multispectral sensor].
Based on the data of the scientific experiment in Urad Front Banner for UAV Remote Sensing Load Calibration Field project, with the help of 6 hyperspectral radiometric targets with good Lambertian property, the wide-view multispectral camera in UAV was calibrated adopting reflectance-based method. The result reveals that for green, red and infrared channel, whose images were successfully captured, the linear correlation coefficients between the DN and radiance are all larger than 99%. In final analysis, the comprehensive error is no more than 6%. The calibration results demonstrate that the hyperspectral targets equipped by the calibration field are well suitable for air-borne multispectral load in-flight calibration. The calibration result is reliable and could be used in the retrieval of geophysical parameters. PMID:23427528
Chen, Wei; Yan, Lei; Gou, Zhi-Yang; Zhao, Hong-Ying; Liu, Da-Ping; Duan, Yi-Ni
The importance and attainment of accurate absolute radiometric calibration
NASA Technical Reports Server (NTRS)
The importance of accurate absolute radiometric calibration is discussed by reference to the needs of those wishing to validate or use models describing the interaction of electromagnetic radiation with the atmosphere and earth surface features. The in-flight calibration methods used for the Landsat Thematic Mapper (TM) and the Systeme Probatoire d'Observation de la Terre, Haute Resolution visible (SPOT/HRV) systems are described and their limitations discussed. The questionable stability of in-flight absolute calibration methods suggests the use of a radiative transfer program to predict the apparent radiance, at the entrance pupil of the sensor, of a ground site of measured reflectance imaged through a well characterized atmosphere. The uncertainties of such a method are discussed.
Slater, P. N.
Radiometric calibration analysis of SIR-B imagery
NASA Technical Reports Server (NTRS)
The second flight of the NASA Spaceborne Imaging Radar (SIR-B) collected nearly 8 hours of digital synthetic-aperture radar (SAR) data of the earth's surface. This paper analyzes the performance of the SAR to determine the accuracy of the relative radiometric calibration of these data. Procedures are presented for deriving accuracy estimates as well as limitations under which these estimates are valid. The impact on calibration of an RF breakdown in the primary antenna feed system cable is evaluated. An analysis of the platform stability based on the SAR echo data is also presented in conjunction with its resultant effect on the calibration accuracy. Finally, numerical error bounds are derived with guidelines on their utilization.
Wall, Stephen D.; Curlander, John C.
Development of a portable ambient temperature radiometric assaying instrument
There is a strong need for portable radiometric instrumentation that can accurately confirm the presence of nuclear materials and allow isotopic analysis of radionuclides in the field. To fulfill this need we are developing a hand-held, non-cryogenic, low-power gamma- and x-ray measurement and analysis instrument that can both search and then accurately verify the presence of nuclear materials. We report on the use of cadmium zinc telluride detectors, signal processing electronics, and the new field-portable instrument based on the MicroNOMAD Multichannel Analyzer from EG&G ORTBC. We also describe the isotopic analysis that allows uranium enrichment measurements to be made accurately in the field.
Lavietes, A.D.; McQuaid, J.H.; Ruhter, W.D.
Calculation of atmospheric loss from microwave radiometric noise temperature measurements
NASA Technical Reports Server (NTRS)
Microwave propagation loss in the atmosphere can be inferred from microwave radiometric noise temperature measurements. The relevant equations are given and a derivation and calculation is made assuming various physical models. Comparison is made with the commonly used lumped element atmospheric model (isothermal and uniform loss) and the model with linear temperature and exponential loss distributions. The results are useful for estimating the integral inversion differences due to the model selection. This indicates that the commonly used lumped element atmospheric model is a very good approximation with judicious choice of the effective physical temperature. For the worst case comparison, the lumped element model agrees with the variable parameter model within 0.2 dB up to a propagation loss of 3 dB.
Stelzried, C.; Slobin, S. D.
Laboratory Measurement of Bidirectional Reflectance of Radiometric Tarps
NASA Technical Reports Server (NTRS)
This experiment measured the reflectance of tarps with ground instruments in order to check radiometric calibration, validate atmospheric correction, and predict at-sensor radiance for satellite instruments. The procedure of this experiment is as follows: 1) Assemble laboratory apparatus to duplicate ground reference measurement geometry and satellite measurement geometry; 2) Measure spectral radiance with Optronics OL 750 double monochromator/spectroradiometer; 3) Measure radiance of NIST-calibrated Spectralon panel irradiated by collimated light at incidence angle of calibrated reflectance (20 deg, 30 deg, 40 deg, or 50 deg), viewing normal to panel surface; 4) Measure radiance of Spectralon panel irradiated at incidence angle equal to solar zenith angle at time of overpass; 5) Calculate reflectance of Spectralon panel irradiated at solar zenith angle, viewing normal to panel surface (ground geometry).
Knowlton, Kelly
San Bernardino Cave (Italy) and the Appearance of Levallois Technology in Europe: Results of a Radiometric and Technological Reassessment
The introduction of Levallois technology in Europe marked the transition from the Lower to the early Middle Paleolithic. This new method of flake production was accompanied by significant behavioral changes in hominin populations. The emergence of this technological advance is considered homogeneous in the European archaeological record at the Marine isotopic stage (MIS) 9/MIS 8 boundary. In this paper we report a series of combined electron spin resonance/U-series dates on mammal bones and teeth recovered from the lower units of San Bernardino Cave (Italy) and the technological analyses of the lithic assemblages. The San Bernardino Cave has yielded the earliest evidence of Levallois production on the Italian Peninsula recovered to date. In addition to our results and the review of the archaeological record, we describe the chronological and geographical differences between European territories and diversities in terms of technological developments. The belated emergence of Levallois technology in Italy compared to western Europe corresponds to the late Italian Neanderthal speciation event. The new radiometric dates and the technological analyses of San Bernardino Cave raise the issue of the different roles of glacial refugia in the peopling and the spread of innovative flaking strategies in Europe during the late Middle Pleistocene.
Picin, Andrea; Peresani, Marco; Falgueres, Christophe; Gruppioni, Giulia; Bahain, Jean-Jacques
Correlations between altimetric sea surface height and radiometric sea surface temperature in the South Atlantic
NASA Astrophysics Data System (ADS)
In the last decade, satellite altimetric measurements of sea surface height (SSH) and infrared radiometric measurements of sea surface temperature (SST) have provided a wealth of information about ocean circulation and atmosphere-ocean interactions. SSH is a depth-integrated quantity dependent upon the temperature and salinity structure of the water column and on the depth independent barotropic contribution. SST from infrared radiometers is a surface parameter representing the temperature of the top few microns of the ocean surface. Hence any relationship between SST and SSH provides dynamical information about the coupling between the ocean surface and subsurface. It also offers a promise of new techniques such as interpolating SSH data using SST and of improved calculations of eddy kinetic energy. We use SST data from the along-track scanning radiometer on ERS-I and SSH data from the TOPEX/POSEIDON instrument to examine the relationship between SST and SSH anomalies within the South Atlantic region for 1993 and 1994. We find that positive (?0.2-0.6) spatial cross correlations between SST and SSH anomalies at zero lag are present throughout the region at large scales (wavelengths >1000 km). Small-scale correlations, however, are high (?0.7) only in areas associated with fronts and mesoscale variability. These small-scale correlations are seasonal, being strongest in winter and weakest in summer. We discuss the application of these correlations to various techniques requiring the synergistic use of SSH and SST data.
Jones, Matthew S.; Allen, Myles; Guymer, Trevor; Saunders, Mark
Radiometric Characterization of the IKONOS, QuickBird, and OrbView-3 Sensors
NASA Technical Reports Server (NTRS)
Radiometric calibration of commercial imaging satellite products is required to ensure that science and application communities can better understand their properties. Inaccurate radiometric calibrations can lead to erroneous decisions and invalid conclusions and can limit intercomparisons with other systems. To address this calibration need, satellite at-sensor radiance values were compared to those estimated by each independent team member to determine the sensor's radiometric accuracy. The combined results of this evaluation provide the user community with an independent assessment of these commercially available high spatial resolution sensors' absolute calibration values.
Holekamp, Kara
Concept, Simulation, and Instrumentation for Radiometric Inflight Icing Detection
NASA Technical Reports Server (NTRS)
The multi-agency Flight in Icing Remote Sensing Team (FIRST), a consortium of the National Aeronautics and Space Administration (NASA), the Federal Aviation Administration (FAA), the National Center for Atmospheric Research (NCAR), the National Oceanographic and Atmospheric Administration (NOAA), and the Army Corps of Engineers (USACE), has developed technologies for remotely detecting hazardous inflight icing conditions. The USACE Cold Regions Research and Engineering Laboratory (CRREL) assessed the potential of onboard passive microwave radiometers for remotely detecting icing conditions ahead of aircraft. The dual wavelength system differences the brightness temperature of Space and clouds, with greater differences potentially indicating closer and higher magnitude cloud liquid water content (LWC). The Air Force RADiative TRANsfer model (RADTRAN) was enhanced to assess the flight track sensing concept, and a 'flying' RADTRAN was developed to simulate a radiometer system flying through simulated clouds. Neural network techniques were developed to invert brightness temperatures and obtain integrated cloud liquid water. In addition, a dual wavelength Direct-Detection Polarimeter Radiometer (DDPR) system was built for detecting hazardous drizzle drops. This paper reviews technology development to date and addresses initial polarimeter performance.
Ryerson, Charles; Koenig, George G.; Reehorst, Andrew L.; Scott, Forrest R.
Radiocarbon dating of ancient rock paintings.
National Technical Information Service (NTIS)
This report presents progress made on a technique for C-14 dating pictographs. A low-temperature oxygen plasma is used coupled with high-vacuum technologies to selectively remove C-containing material in the paints without contamination from inorganic car...
W. A. Ilger M. Hyman M. W. Rowe J. Southon
Imaging and radiometric performance simulation for a new high-performance dual-band airborne reconnaissance camera
NASA Astrophysics Data System (ADS)
In recent years, high performance visible and IR cameras have been used widely for tactical airborne reconnaissance. The process improvement for efficient discrimination and analysis of complex target information from active battlefields requires for simultaneous multi-band measurement from airborne platforms at various altitudes. We report a new dual band airborne camera designed for simultaneous registration of both visible and IR imagery from mid-altitude ranges. The camera design uses a common front end optical telescope of around 0.3m in entrance aperture and several relay optical sub-systems capable of delivering both high spatial resolution visible and IR images to the detectors. The camera design is benefited from the use of several optical channels packaged in a compact space and the associated freedom to choose between wide (~3 degrees) and narrow (~1 degree) field of view. In order to investigate both imaging and radiometric performances of the camera, we generated an array of target scenes with optical properties such as reflection, refraction, scattering, transmission and emission. We then combined the target scenes and the camera optical system into the integrated ray tracing simulation environment utilizing Monte Carlo computation technique. Taking realistic atmospheric radiative transfer characteristics into account, both imaging and radiometric performances were then investigated. The simulation results demonstrate successfully that the camera design satisfies NIIRS 7 detection criterion. The camera concept, details of performance simulation computation, the resulting performances are discussed together with future development plan.
Seong, Sehyun; Yu, Jinhee; Ryu, Dongok; Hong, Jinsuk; Yoon, Jee-Yeon; Kim, Sug-Whan; Lee, Jun-Ho; Shin, Myung-Jin
Mars chronology: assessing techniques for quantifying surficial processes
NASA Technical Reports Server (NTRS)
Currently, the absolute chronology of Martian rocks, deposits and events is based mainly on crater counting and remains highly imprecise with epoch boundary uncertainties in excess of 2 billion years. Answers to key questions concerning the comparative origin and evolution of Mars and Earth will not be forthcoming without a rigid Martian chronology, enabling the construction of a time scale comparable to Earth's. Priorities for exploration include calibration of the cratering rate, dating major volcanic and fluvial events and establishing chronology of the polar layered deposits. If extinct andor extant life is discovered, the chronology of the biosphere will be of paramount importance. Many radiometric and cosmogenic techniques applicable on Earth and the Moon will apply to Mars after certain baselines (e.g. composition of the atmosphere, trace species, chemical and physical characteristics of Martian dust) are established. The high radiation regime may pose a problem for dosimetry-based techniques (e.g. luminescence). The unique isotopic composition of nitrogen in the Martian atmosphere may permit a Mars-specific chronometer for tracing the time-evolution of the atmosphere and of lithic phases with trapped atmospheric gases. Other Mars-specific chronometers include measurement of gas fluxes and accumulation of platinum group elements (PGE) in the regolith. Putting collected samples into geologic context is deemed essential, as is using multiple techniques on multiple samples. If in situ measurements are restricted to a single technique it must be shown to give consistent results on multiple samples, but in all cases, using two or more techniques (e.g. on the same lander) will reduce error. While there is no question that returned samples will yield the best ages, in situ techniques have the potential to be flown on multiple missions providing a larger data set and broader context in which to place the more accurate dates.
Doran, Peter T.; Clifford, Stephen M.; Forman, Steven L.; Nyquist, Larry; Papanastassiou, Dimitri A.; Stewart, Brian W.; Sturchio, Neil C.; Swindle, Timothy D.; Cerling, Thure; Kargel, Jeff
Mars chronology: Assessing techniques for quantifying surficial processes
Currently, the absolute chronology of Martian rocks, deposits and events is based mainly on crater counting and remains highly imprecise with epoch boundary uncertainties in excess of 2 billion years. Answers to key questions concerning the comparative origin and evolution of Mars and Earth will not be forthcoming without a rigid Martian chronology, enabling the construction of a time scale comparable to Earth's. Priorities for exploration include calibration of the cratering rate, dating major volcanic and fluvial events and establishing chronology of the polar layered deposits. If extinct and/or extant life is discovered, the chronology of the biosphere will be of paramount importance. Many radiometric and cosmogenic techniques applicable on Earth and the Moon will apply to Mars after certain baselines (e.g. composition of the atmosphere, trace species, chemical and physical characteristics of Martian dust) are established. The high radiation regime may pose a problem for dosimetry-based techniques (e.g. luminescence). The unique isotopic composition of nitrogen in the Martian atmosphere may permit a Mars-specific chronometer for tracing the time-evolution of the atmosphere and of lithic phases with trapped atmospheric gases. Other Mars-specific chronometers include measurement of gas fluxes and accumulation of platinum group elements (PGE) in the regolith. Putting collected samples into geologic context is deemed essential, as is using multiple techniques on multiple samples. If in situ measurements are restricted to a single technique it must be shown to give consistent results on multiple samples, but in all cases, using two or more techniques (e.g. on the same lander) will reduce error. While there is no question that returned samples will yield the best ages, in situ techniques have the potential to be flown on multiple missions providing a larger data set and broader context in which to place the more accurate dates. ?? 2004 Elsevier B.V. All rights reserved.
Doran, P. T.; Clifford, S. M.; Forman, S. L.; Nyquist, L.; Papanastassiou, D. A.; Stewart, B. W.; Sturchio, N. C.; Swindle, T. D.; Cerling, T.; Kargel, J.; McDonald, G.; Nishiizumi, K.; Poreda, R.; Rice, J. W.; Tanaka, K.
Offset Reflector with Horn Feed Array, Used as an Experimental Sensor for Radiometric Measurements.
National Technical Information Service (NTIS)
A sensor consisting of a single offset reflector antenna with five beams for radiometric measurements with multiple receivers is presented. The design procedure and the arrangement of the feeds is described. A procedure for the exact adjustment of the ref...
H. J. Steiner
Offset-Reflector with Horn Feed Array as an Experimental Sensor for Radiometric Measurements.
National Technical Information Service (NTIS)
A sensor consisting of a single offset reflector antenna with five beams for radiometric measurements with multiple receivers is presented. The design procedure and the arrangement of the feeds is described. A procedure for the exact adjustment of the ref...
H. J. Steiner
Experimental Research on Passive Millimeter Wave Radiometric Stealth Technology of Metal Objects
NASA Astrophysics Data System (ADS)
Working all day and all weather, a passive millimeter wave radiometer (PMMW) can be widely used in civil and military affairs. It can get some specific information about the material characteristics different from radar and infrared detectors. On basis of the radiometric operating range equation, the radiation cross section and stealth effect of metal objects are presented for the PMMW near-sensing application. The measurement experiments of metal solid models adopts 3 mm band Dicke radiometer with the outdoor calibration system. The sky temperature and other different surface metal objects are also measured as the contrastive experiments. The results show the radiometric temperature contrasts of solid models have remarkable difference in the bare and coated conditions, and the radiometric operating range can decrease to 60.8 %. In addition, the PMMW stealth methods through different surface treatment respectively reduce the radiometric antenna temperature contrast in some degree.
Zhang, Guangfeng; Lou, Guowei; Li, Xingguo
Intra-annual NDVI validation of the Landsat 5 TM radiometric calibration
Multispectral data from the Landsat 5 (L5) Thematic Mapper (TM) sensor provide the backbone of the extensive archive of moderate-resolution Earth imagery. Even after more than 24 years of service, the L5 TM is still operational. Given the longevity of the satellite, the detectors have aged and the sensor's radiometric characteristics have changed since launch. The calibration procedures and parameters in the National Land Archive Production System (NLAPS) have also changed with time. Revised radiometric calibrations in 2003 and 2007 have improved the radiometric accuracy of recently processed data. This letter uses the Normalized Difference Vegetation Index (NDVI) as a metric to evaluate the radiometric calibration. The calibration change has improved absolute calibration accuracy, consistency over time, and consistency with Landsat 7 (L7) Enhanced Thematic radiometry and will provide the basis for continued long-term studies of the Earth's land surfaces.
Chander, G.; Groeneveld, D. P.
Spectral Detection of Human Skin in VIS-SWIR Hyperspectral Imagery without Radiometric Calibration.
National Technical Information Service (NTIS)
Many spectral detection algorithms require precise ground truth measurements that are hand-selected in the image to apply radiometric calibration, converting image pixels into estimated re ectance vectors. That process is impractical for mobile, real-time...
A. P. Beisley
Simultaneous Inflight Spectral and Radiometric Calibration Validation of AVRIS and HYDICE Over Lunar Lake, Nevada
NASA Technical Reports Server (NTRS)
An experiment to check the spectral and radiometric calibration of two sensors--the airborne visible/infrared imaging spectromenter (AVRIS) and the Hyperspectral digital image collection experiment (HYDICE)--is described.
Chrien, Thomas; Green, Robert; Chovit, Chris; Faust, Jessica; Johnson, Howell; Basedow, Robert; Zalewski, Edward; Colwell, John
Flight Technology Improvement. [spaceborne optical radiometric instruments, attitude control, and electromechanical and power subsystems
NASA Technical Reports Server (NTRS)
Shortcomings in spaceborne instrumentation technology are analyzed and recommendations are given for corrections and technology development. The technologies discussed are optical radiometric instruments and calibration, attitude control and determination, and electromechanical and power subsystems.
Violence in Adolescent Dating Relationships
ERIC Educational Resources Information Center
Beginning with a definition of dating and dating violence among adolescents, this article explores the factors which impact such violence. It concludes with a review of two school-based prevention/intervention programs (Safe Dates and The Youth Relationships Project). (Contains 1 table.)
Jouriles, Ernest N.; Platt, Cora; McDonald, Renee
A near-realtime geolocated and radiometric corrected low-resolution ERS-1 SAR image product
An operational algorithm is developed and implemented for geolocation and radiometric correction of the near-realtime low-resolution ERS-1 SAR image product from Tromso Satellite Station (TSS). Latitude and longitude grids and land-contours are mapped into the image. The radiometric correction adjusts the pixel intensity for varying antenna gain across the swath and range spreading loss. The antenna gain is based on
I. Lauknes; H. Johnsen
Quantitative measurements of sliding friction coefficients of tribological interfaces with a new differential infrared radiometric instrument
Experimental sliding friction coefficient (SFC) measurements using a mechanical friction rig and infrared radiometric emission data from a novel instrument monitoring radiant heat generation at the tribological interface of the rig are described. The infrared radiometric (IRM) system features thermal-emission-intensity harmonic modulation with background-radiation-compensating wave forms, leading to differential signal operation mode and suppression of ambient radiation. The mechanical friction
Andreas Mandelis; Li Li; Natalie Baddour; Rod C. Tennyson; W. Don Morrison
Study of Spectral/Radiometric Characteristics of the Thematic Mapper for Land Use Applications
NASA Technical Reports Server (NTRS)
An investigation conducted in support of the LANDSAT 4/5 Image Data Quality Analysis (LIDQA) Program is discussed. Results of engineering analyses of radiometric, spatial, spectral, and geometric properties of the Thematic Mapper systems are summarized; major emphasis is placed on the radiometric analysis. Details of the analyses are presented in appendices, which contain three of the eight technical papers produced during this investigation; these three, together, describe the major activities and results of the investigation.
Malila, W. A. (principal investigator); Metzler, M. D. (principal investigator)
A multi-channel radiometric profiler of temperature, humidity and cloud liquid.
A microwave radiometer is described that provides continuous thermodynamic (temperature, water vapor, and moisture) soundings during clear and cloudy conditions. The radiometric profiler observes radiation intensity at 12 microwave frequencies, along with zenith infrared and surface meteorological measurements. Historical radiosonde and neural network or regression methods are used for profile retrieval. We compare radiometric, radiosonde, and forecast soundings and evaluate the accuracy of radiometric temperature and water vapor soundings on the basis of statistical comparison with radiosonde soundings. We find that radiometric soundings are equivalent in accuracy to radiosonde soundings when used in numerical weather forecasting. A case study is described that demonstrates improved fog forecasting on the basis of variational assimilation of radiometric soundings. The accuracy of radiometric cloud liquid soundings is evaluated by comparison with cloud liquid sensors carried by radiosondes. Accurate high-resolution three-dimensional water vapor and wind analysis is described on the basis of assimilation of simulated thermodynamic and wind soundings along with GPS slant delays. Examples of mobile thermodynamic and wind profilers are shown. Thermodynamic profiling, particularly when combined with wind profiling and slant GPS, provides continuous atmospheric soundings for improved weather and dispersion forecasting.
Ware, R.; Carpenter, R.; Guldner, J.; Liljegren, J.; Nehrkorn, T.; Solheim, F.; Vandenberghe, F.; Environmental Research; Radiometrics Corp.; Univ. Corp. for Atmospheric Research; Weather Decision Technologies Inc.; Atmospheric and Environmental Research Inc.; National Center for Atmospheric Research
High-Precision U-Pb Zircon Dates as Benchmarks in Absolute Time
NASA Astrophysics Data System (ADS)
High-precision IDTIMS U-Pb zircon dates provide the most precise and accurate isotopic benchmarks in absolute time, due to the concordancy check of the paired U-Pb decay schemes, the precisely measured 235U and 238U decay constants, very high initial parent/daughter ratios, and the robust nature of zircon to loss or gain of U and Pb over geologic time. However, caveats to the use of such zircon dates include the accurate assessment and minimization of random and systematic errors in the analytical methods, and decay constant uncertainties. Unfortunately, there exists little consensus within the U-Pb geochronological community regarding an international zircon standard for the external assessment of interlaboratory reproducibility, while residual questions remain regarding the potential for systematic error in the single available high-precision counting experiment of the U decay constants1. Stringent criteria are imposed on candidates for zircon geochronology standards including the absence of inheritance and Pb-loss at both the single grain scale and the resolution of microbeam techniques. We present an example of the potential and limitations of a possible zircon standard, AS3, from the Duluth Complex, North American Midcontinent Rift2. New data for 27 single zircons are indistinguishable from prior results, with 207Pb/206Pb and upper intercept dates identical within error to a U-Pb concordia date of 1099.1+/-0.2 Ma (+/-1.2 Ma with systematic errors) based on 12 concordant and equivalent analyses. However, we must reiterate that a zircon population exhibiting consistent concordancy remains elusive, as AS3 and all Paleozoic and older standard candidates so far examined contain grains exhibiting Pb-loss, although rigorous selection and preparation of zircons through diamagnetic separation and aggressive abrasion can mitigate this phenomenon. The continued screening of candidate standards by both IDTIMS and SHRIMP techniques should be an organized, international endeavor involving all high-precision geochronology laboratories. Under the single assumption that the equivalent data represent the approach to closed system behavior, the correspondence of the AS3 zircons with the presently defined concordia curve suggests the accuracy of the ratio of the presently accepted decay constants1 to within their 0.1% (2? ) counting errors. While a proposed revision of the 235U decay constant3 is apparently unnecessary, additional high-precision, high n, statistically equivalent zircon population samplings are necessary to further evaluate decay constants and their uncertainties at the per mil level. When measured on appropriate lithologies, high-precision U-Pb dates also become powerful tools for the intercalibration of other radioisotope decay rates more difficult to measure through counting or accumulation (e.g. 40K, 176Lu, 187Re). We will present several new high-precision data sets for quickly cooled Oligocene to Archean extrusive and intrusive rocks, and assess their usefulness as benchmarks for the intercalibration of radiometric time; a growing number of high-precision U-Pb zircon and 40Ar/39Ar feldspar, biotite or hornblende pairs spanning more than 3 Ga in absolute time indicate a consistently younger bias in 40Ar/39Ar dates of between 0.7 and 1%. 1Jaffey et al. (1974) Phys Rev C 4:1889-1906; 2Paces and Miller (1993) J Geophys Res 98:13997-14013; 3Mattinson (2000) EOS 81:S444
Schmitz, M. D.; Bowring, S. A.; Schoene, B.
New radiometric and geomorphologic evidences of a last glacial maximum older than 18 ka in SW European mountains: the example of Redes Natural Park (Cantabrian Mountains, NW Spain)
NASA Astrophysics Data System (ADS)
The first numerical age determinations from radiocarbon dating establish the chronology of glacial events in Redes Natural Park (Cantabrian Mountain, NW Spain). A core drilled in an ice-dammed deposit provided a minimum age of 28?990 � 230 years BP for the maximum glacial expansion (phase I). Another core from a cirque bottom-fill provided organic sediment with 20?640 � 300 years BP, a minimum age for the first glacial retreat (phase II). Radiometric dating of proglacial deposits interpreted as synchronous with the last glacial maximum phase in neighbouring Comella basin (Picos de Europa), yield ages of 40?480 � 820 years BP. The chronological data presented in this work are consistent with the model of glacier evolution established in the Pyr�n�es, with a glacial maximum phase for the last glacial period older than 18 ka.
S�nchez, Montserrat Jim�nez; Arquer, Pedro Farias
Geology Labs Online: Virtual Dating
NSDL National Science Digital Library
This interactive feature lets students investigate how absloute (numerical) dates are determined for rocks, minerals, and organic (carbon-containing) material. Topics include radioactive decay and the use of isotope ratios to obtain ages in years; the difference between relative and absolute dating; the use of rubidium-strontium isotope ratios to date rocks and minerals; the development of radiocarbon dating in the 1940s by Willard F. Libby; and the use of tree ring data to calibrate radiocarbon dates. After each section, students answer study questions before continuing to the next step in the exercise.
Parathyrin assay. An analytical evaluation of two commercial Immuno Radiometric Assay kits.
We have performed a comparative evaluation of two Immuno Radiometric Assay (IRMA) kits for parathyrin against an existing Radioimmuno Assay (RIA) technique for the measurement of intact parathyrin. The analytical evaluation which was performed in line with the ECCLS recommended kit evaluation protocol showed a marginal improvement in precision with the new assays. There was a substantial improvement in the theoretical limit of detection utilising the IRMA kits although it may prove difficult to realize this improvement in practice with individual samples because of differing protein matrices. The evaluation also demonstrated the degree of parallelism and range of linearity of both kits as well as inaccuracies when compared with the International Reference Preparation for parathyrin (IRP 79/500) as the accepted standard. The demonstration of lack of agreement between measured and kit assigned results for standards when cross-over studies between kits were performed may highlight a possible contributing factor to inaccuracy. Alternatively there may be a difference of antisera avidity within the kits for intact parathyrin. Whilst minor differences in sample stability were demonstrated between the kits, the sample stability was much improved compared to that for intact parathyrin measurement by RIA. The correlation studies showed a degree of correlation consistent with other comparisons similarly performed. PMID:2358790
Pledger, D R; Carr, C; Sims, T I; Johnson, K R
76 FR 77831 - 2012 Presidential Candidate Matching Fund Submission Dates and Post Date of Ineligibility Dates...
Federal Register 2010, 2011, 2012, 2013
The Federal Election Commission is publishing matching fund submission dates for publicly funded 2012 presidential primary candidates. Eligible candidates may present one submission and/or resubmission per month on the designated date. The Commission is also publishing the dates on which publicly funded 2012 presidential primary candidates must submit their statements of net outstanding campaign......
Radiometric modeling of a 3D imaging laser scanner
NASA Astrophysics Data System (ADS)
Active imaging systems allow obtaining data in more than two dimensions. In addition to the spatial information, these systems are able to provide the intensity distribution of one scene. From this data channel a certain number of physic magnitudes that show some features of the illuminated surface can be recovered. The different behaviours of the scene elements about the directionality of the optical radiation, wavelength or polarization improve the ability to discriminate them. In this work, the capabilities of one 3D imaging laser scanner have been tested from both dimensional and radiometric points of view. To do this, a simple model of the observing system and the scene, in which only the directional propagation of the energy is taken into account, has been developed. Selected parameters corresponding to transmission, reception and optomechanical components of the active imaging system describe the full sensor. The surfaces of a non-complex scene have been divided into different elements with a defined geometry and directional reflectance. In order to measure the directional reflectance of several materials in the specific wavelength where the laser scanner works, a laboratory bench has been developed. The calculation of the received signal by the sensor has been carried out using several radiative transfer models. These models were validated by experiments in a laboratory with controlled conditions of illumination and reflectance. To do this, a certain number of images (angle, angle, range and intensity) were acquired by a commercial laser scanner using several standard targets calibrated in geometry and directional reflectance.
Ortiz, Sergio; Diaz-Caro, Jose; Pareja, Rosario
Design, manufacture, and calibration of infrared radiometric blackbody sources
A Radiometric Calibration Station (RCS) is being assembled at the Los Alamos National Laboratories (LANL) which will allow for calibration of sensors with detector arrays having spectral capability from about 0.4-15 {mu}m. The configuration of the LANL RCS. Two blackbody sources have been designed to cover the spectral range from about 3-15 {mu}m, operating at temperatures ranging from about 180-350 K within a vacuum environment. The sources are designed to present a uniform spectral radiance over a large area to the sensor unit under test. The thermal uniformity requirement of the blackbody cavities has been one of the key factors of the design, requiring less than 50 mK variation over the entire blackbody surface to attain effective emissivity values of about 0.999. Once the two units are built and verified to the level of about 100 mK at LANL, they will be sent to the National Institute of Standards and Technology (NIST), where at least a factor of two improvement will be calibrated into the blackbody control system. The physical size of these assemblies will require modifications of the existing NIST Low Background Infrared (LBIR) Facility. LANL has constructed a bolt-on addition to the LBIR facility that will allow calibration of our large aperture sources. Methodology for attaining the two blackbody sources at calibrated levels of performance equivalent to present state of the art will be explained in the following.
Byrd, D.A.; Michaud, F.D.; Bender, S.C. [and others
Radiometric oil well assay for glucokinase in microscopic structures
Glucokinase plays a pivotal role in hepatic glucose metabolism and serves as the glucose sensor in pancreatic islet beta-cells. Biochemical studies of this enzyme are complicated by the cellular heterogeneity of the liver and the pancreas and because the presence of hexokinases seriously interferes with currently available analytical procedures. A radiometric assay was designed to deal with these problems. It is based on the liberation of /sup 3/H/sub 2/O from D-(2-/sup 3/H(N))glucose 6-phosphate, the product of the glucokinase reaction, using exogenous phosphoglucose isomerase. Interference by hexokinases was largely eliminated by using glucose 6-phosphate as inhibitor and the sensitivity of the assay was greatly increased by using small volumes with the oil well procedure. The assay was sufficiently sensitive to detect about 1 pg of glucokinase. It thus allowed the application of quantitative histochemical procedures to the study of intralobular hepatic glucokinase profiles and the pancreatic beta-cell glucose sensor. The quantitative histochemical procedures were sufficiently sensitive and reliable for measuring important kinetic constants of glucokinase in microscopic samples of tissue.
Bedoya, F.J.; Meglasson, M.D.; Wilson, J.M.; Matschinsky, F.M.
Optimized mapping of radiometric quantities into OpenGL
NASA Astrophysics Data System (ADS)
Physically realistic synthesis of FLIR imagery requires intensive phenomenology calculations of the spectral band thermal emission and reflection from scene elements in the database. These calculations predict the heat conduction, convection, and radiation exchange between scene elements and the environment. Balancing this requirement is the need for imagery to be presented to a display in a timely fashion, often in real time. In order to support these conflicting requirements, some means of overcoming the gap between real time and high fidelity must be achieved. Over the past several years, the US Army Night Vision and Electronic Sensors Directorate (NVESD) has been developing a real-time forward looking infrared sensor simulation known as Paint the Night (PTN). As part of this development, NVESD has explored schemes for optimizing signature models and for mapping model radiometric output into parameters compatible with OpenGL, real-time rendering architectures. Relevant signature and mapping optimization issues are discussed, and a current NVESD PTN real-time implementation scheme is presented.
Lorenzo, Maximo; Jacobs, Eddie L.; Moulton, Joseph R.; Liu, Jesse
Robust Multiscale Stereo Matching from Fundus Images with Radiometric Differences
A robust multiscale stereo matching algorithm is proposed to find reliable correspondences between low contrast and weakly textured retinal image pairs with radiometric differences. Existing algorithms designed to deal with piecewise planar surfaces with distinct features and Lambertian reflectance do not apply in applications such as 3D reconstruction of medical images including stereo retinal images. In this paper, robust pixel feature vectors are formulated to extract discriminative features in the presence of noise in scale space, through which the response of low-frequency mechanisms alter and interact with the response of high-frequency mechanisms. The deep structures of the scene are represented with the evolution of disparity estimates in scale space, which distributes the matching ambiguity along the scale dimension to obtain globally coherent reconstructions. The performance is verified both qualitatively by face validity and quantitatively on our collection of stereo fundus image sets with ground truth, which have been made publicly available as an extension of standard test images for performance evaluation.
Tang, Li; Garvin, Mona K.; Lee, Kyungmoo; Alward, Wallace L.M.; Kwon, Young H.; Abramoff, Michael D.
Enhancing the simulation of radiometric instrument models using genetic algorithms
NASA Astrophysics Data System (ADS)
A primary objective of the effort described here is to optimize the performance of a modeling environment for radiometric instruments capable of predicting their complete end-to-end behavior, integrating the optical, electrothermal, and electronic systems. The numerical environment consists of a Monte Carlo ray-trace (MCRT) model of the optical system coupled to a transient three-dimensional finite-difference electrothermal model of the detector assembly with an analytical model of the signal-conditioning circuitry. The resulting model provides a complete simulation of the dynamic optical and electrothermal behavior of the instrument. The modeling environment has been used to create an end-to-end model of the CERES scanning radiometer, and its performance compared to the calibration performance of an operational CERES total channel as a benchmark. To optimize the accuracy of the electrothermal model, the nominal properties of certain key parameters in that model are modified using an evolutionary search algorithm such that the model's simulated output exactly matches the actual instrument ground calibration data. Results indicate that varying the layer thickness, effective thermal conductivity, and effective thermal capacitance of the thermistor, kapton, and epoxy layers in the thermistor bolometer within reasonable uncertainty bounds provides an excellent match with the recorded instrument data.
Sorensen, Ira J.; Mahan, James R.
A radiometric assay for glutamine:fructose-6-phosphate amidotransferase.
Glutamine:fructose-6-phosphate amidotransferase (GFAT) catalyzes the first step in the biosynthesis of amino sugars by transferring the amino group from l-glutamine to the acceptor substrate, fructose 6-phosphate, generating the products glucosamine 6-phosphate and glutamic acid. We describe a method for the synthesis and purification of the substrate, fructose 6-phosphate, and methods for a radiometric assay of human GFAT1 that can be performed in either of two formats: a small disposable-column format and a high-throughput 96-well-plate format. The method performed in the column format can detect 1 pmol of glucosamine 6-phosphate, much less than that required by previously published assays that measure GlcN 6-phosphate. The column assay demonstrates a broad linear range with low variability. In both formats, the assay is linear with time and enzyme concentration and is highly reproducible. This method greatly improves the sensitivity and speed with which GFAT1 activity can be measured and facilitates direct kinetic measurement of the transferase activity. PMID:12018941
Broschat, Kay O; Gorka, Christine; Kasten, Thomas P; Gulve, Eric A; Kilpatrick, Brian
Testing the radiometric stability of HCMM thermal infrared data
NASA Technical Reports Server (NTRS)
A study conducted to test the radiometric stability of thermal infrared (TIR) data from the heat-capacity mapping mission (HCMM) satellites is considered. The radiance values associated with various land use and cover types in a regional study area centered on Washington, D.C. are examined. The study shows that for three different day TIR-data sets, the relative ranking of mean thermal values associated with five Level I and three Level II land-use/land-cover categories remains constant over time. Although HCMM predicted temperatures show variability up to 5 C from ground observed temperatures, the thermal measurements recorded by the satellite are fairly stable as indicators of surface temperature. A method for combining HCMM thermal data and Landsat multispectral scanner (MSS) data to improve the classification of Level I land-cover categories, and in particular the separability of urban and nonurban areas is described. A merged HCMM-MSS data set is found to yield the best results in terms of thematic-map accuracy.
Witt, R. G.; Sekhon, R. S.; Minor, T. B.
Structure and dating errors in the geologic time scale and periodicity in mass extinctions
NASA Technical Reports Server (NTRS)
Structure in the geologic time scale reflects a partly paleontological origin. As a result, ages of Cenozoic and Mesozoic stage boundaries exhibit a weak 28-Myr periodicity that is similar to the strong 26-Myr periodicity detected in mass extinctions of marine life by Raup and Sepkoski. Radiometric dating errors in the geologic time scale, to which the mass extinctions are stratigraphically tied, do not necessarily lessen the likelihood of a significant periodicity in mass extinctions, but do spread the acceptable values of the period over the range 25-27 Myr for the Harland et al. time scale or 25-30 Myr for the DNAG time scale. If the Odin time scale is adopted, acceptable periods fall between 24 and 33 Myr, but are not robust against dating errors. Some indirect evidence from independently-dated flood-basalt volcanic horizons tends to favor the Odin time scale.
Stothers, Richard B.
Dating of Submarine Landslides and Their Tsunami Deposits Using Hawaii as an Example
NASA Astrophysics Data System (ADS)
There have been several approaches to dating the initiation of submarine landslides and the tsunamis they inevitably produce. In Hawaii, the timing of flank failures of major volcanoes has been estimated by radiometric and paleomagnetic dating of the youngest shield-building flows and dikes, the apex ages of the volcanoes, which can also be constrained by the oldest flows of post-collapse volcanism. More precise age estimates can be obtained by direct dating of the landslide. These approaches include paleomagnetic and U-series stratigraphic dating of the overlying pelagic sediment cover upon and in front of the landslide, the latter method producing minimum ages of last landslide turbidite emplacement, e.g., the ca. 120 ka Alika phase 2 event. Elevated, detached landslide blocks make the best targets for such dating because it is assumed that smaller post-emplacement turbidites will not reach their summits. Catastrophic events such as the 1.0 Ma Wailau giant landslide have, however, been dated by turbidite deposition upon large, elevated blocks of the nearby 1.8 Ma Nuuanu giant landslide. Other direct methods for older events include use of thickness of ferromanganese crusts collected from steep, exposed rock scarps and cosmogenic Be-10 or U-series radiometric determination of the few mm/Ma rate of accumulation. In subtropical areas such as Hawaii, coral clast-bearing, elevated marine deposits on the southeastern islands have been identified as deposits from giant tsunamis. Among the key evidence are the great age and paleo-elevations of the coral clasts found in situ. Since modern coral clasts are relatively young, a few thousand years old or less, older analogs swept from the presently submerged reefs offshore can reliably date tsunamigenic depositional events within the late Quaternary using U-series methods. The age of the tsunami will date within these limits (and the analytical precisions) to the youngest in situ coral clast that was entrained by the waves. U-series dates approximately coeval with the Alika 2 giant landslide suggest a youngest 100 ka tsunami emplacement age from 100-137 ka corals collected on Lanai and Hawaii; likewise, older deposits on Molokai and Lanai suggest a 200 ka tsunami emplacement age from corals that range 200-258 ka in age, but interpretative care must be taken as open-system behavior upon weathering may produce apparently younger dates. Other promising methods for dating these deposits include cosmogenic Cl-36 exposure ages of cements and Cl-36 and He-3 exposure ages of the entrained volcanic rocks. Younger events can be dated by the above methods using C-14 or unsupported Pb-210.
McMurtry, G. M.; Herrero-Bervera, E.
Non-Conventional Measurement Techniques for the Determination of Some Long-Lived Radionuclides Produced in Nuclear Fuel. Literature Survey.
National Technical Information Service (NTIS)
The results of a literature survey on non-radiometric analytical techniques for the determination of long-lived radionuclides are described. The methods which have been considered are accelerator mass spectrometry, inductively coupled plasma mass spectrom...
R. J. Rosenberg
Date Attachable Offline Electronic Cash Scheme
Electronic cash (e-cash) is definitely one of the most popular research topics in the e-commerce field. It is very important that e-cash be able to hold the anonymity and accuracy in order to preserve the privacy and rights of customers. There are two types of e-cash in general, which are online e-cash and offline e-cash. Both systems have their own pros and cons and they can be used to construct various applications. In this paper, we pioneer to propose a provably secure and efficient offline e-cash scheme with date attachability based on the blind signature technique, where expiration date and deposit date can be embedded in an e-cash simultaneously. With the help of expiration date, the bank can manage the huge database much more easily against unlimited growth, and the deposit date cannot be forged so that users are able to calculate the amount of interests they can receive in the future correctly. Furthermore, we offer security analysis and formal proofs for all essential properties of offline e-cash, which are anonymity control, unforgeability, conditional-traceability, and no-swindling.
Sun, Wei-Zhe; Hau, Hoi-Tung
Date attachable offline electronic cash scheme.
Electronic cash (e-cash) is definitely one of the most popular research topics in the e-commerce field. It is very important that e-cash be able to hold the anonymity and accuracy in order to preserve the privacy and rights of customers. There are two types of e-cash in general, which are online e-cash and offline e-cash. Both systems have their own pros and cons and they can be used to construct various applications. In this paper, we pioneer to propose a provably secure and efficient offline e-cash scheme with date attachability based on the blind signature technique, where expiration date and deposit date can be embedded in an e-cash simultaneously. With the help of expiration date, the bank can manage the huge database much more easily against unlimited growth, and the deposit date cannot be forged so that users are able to calculate the amount of interests they can receive in the future correctly. Furthermore, we offer security analysis and formal proofs for all essential properties of offline e-cash, which are anonymity control, unforgeability, conditional-traceability, and no-swindling. PMID:24982931
Fan, Chun-I; Sun, Wei-Zhe; Hau, Hoi-Tung
Performance in a social context: Date rape versus date right
This investigation examined performance of texts as a method of modifying sexual attitudes and assertiveness in a dating context in order to prevent date rape or unwanted sexual aggression. The study focused on the impact of three training modalities (live performance, performance plus discussion, and discussion) and aggressive sexual experience on sexual attitudes and assertive behavior. Results suggest that live
Cynthia A. Mann; Michael L. Hecht; Kristin B. Valentine
Radiometric calibration of a polarization-sensitive sensor
NASA Technical Reports Server (NTRS)
The radiometric accuracy of a sensor is adversely affected by scene polarization if its optical system is sensitive to polarization. Tests performed on the reflective bands of the NS001 Thematic Mapper simulator, an aircraft multispectral scanner, show that it is very sensitive to the polarization state of the incoming radiations. For 100 percent linearly polarized light, errors in the measured intensity vary from -40 to +40 percent, depending on the scan angle and spectral band. To estimate polarization-induced errors in the intensity measured at aircraft level, the intensity and polarization of the atmospheric radiances were simulated using a realistic earth-atmosphere radiative transfer model. For the polarization of atmospheric radiances in the solar meridian plane over a vegetated target, intensity errors may range from -10 to + 10 percent. The polarization-induced errors are highest in the shortest NS001 spectral band (0.450-0.525 microns) because of large atmospheric polarizations contributed by Rayleigh particles and small diluting effects caused by the small contributions of weakly polarized radiations coming from aerosols and the surface. Depending on the illumination and view angles, the errors in derived surface reflectance due to the radiance errors can be very large. In particular, for large off-nadir view angles in the forward scattered direction when the sun is low, the relative errors in the derived surface reflectance can be as large as 4 to 5 times the relative error in the radiances. Polarization sensitivity errors cannot be neglected for the shorter wavelengths when the surface reflectance contribution to atmospheric radiances is very small.
Ahmad, Suraiya P.; Markham, Brian L.
An overview of MODIS radiometric calibration and characterization
NASA Astrophysics Data System (ADS)
The Moderate Resolution Imaging Spectroradiometer (MODIS) is one of the key instruments for NASA's Earth Observing System (EOS), currently operating on both the Terra and Aqua satellites. The MODIS is a major advance over the previous generation of sensors in terms of its spectral, spatial, and temporal resolutions. It has 36 spectral bands: 20 reflective solar bands (RSB) with center wavelengths from 0.41 to 2.1 mu m and 16 thermal emissive bands (TEB) with center wavelengths from 3.7 to 14.4 mu m, making observations at three spatial resolutions: 250 in (bands 1-2), 500 m (hands 3-7), and 1km (bands 8-36). MODIS is a cross-track scanning radiometer with a wide field-of-view, providing a complete global coverage of the Earth in less than 2 days. Both Terra and Aqua MODIS went through extensive pre-launch calibration and characterization at various levels. In orbit, the calibration and characterization tasks are performed using its on-board calibrators (OBCs) that include a solar diffuser (SD) and a solar diffuser stability monitor (SDSM), a v-grooved flat panel blackbody (BB), and a spectro-radiometric calibration assembly (SRCA). In this paper, we present an overview of MODIS calibration and characterization activities, methodologies, and lessons learned from pre-launch characterization and in-orbit operation. Key issues discussed in this paper include in-orbit efforts of monitoring the noise characteristics of the detectors, tracking the solar diffuser and optics degradations, and updating the sensor's response versus scan angle. The experiences and lessons learned through MODIS have played and will continue to play major roles in the design and characterization of future sensors.
Xiong, X. X.; Barnes, W.
Wafer-level radiometric performance testing of uncooled microbolometer arrays
NASA Astrophysics Data System (ADS)
A turn-key semi-automated test system was constructed to perform on-wafer testing of microbolometer arrays. The system allows for testing of several performance characteristics of ROIC-fabricated microbolometer arrays including NETD, SiTF, ROIC functionality, noise and matrix operability, both before and after microbolometer fabrication. The system accepts wafers up to 8 inches in diameter and performs automated wafer die mapping using a microscope camera. Once wafer mapping is completed, a custom-designed quick insertion 8-12 ?m AR-coated Germanium viewport is placed and the chamber is pumped down to below 10-5 Torr, allowing for the evaluation of package-level focal plane array (FPA) performance. The probe card is electrically connected to an INO IRXCAM camera core, a versatile system that can be adapted to many types of ROICs using custom-built interface printed circuit boards (PCBs). We currently have the capability for testing 384x288, 35 ?m pixel size and 160x120, 52 ?m pixel size FPAs. For accurate NETD measurements, the system is designed to provide an F/1 view of two rail-mounted blackbodies seen through the Germanium window by the die under test. A master control computer automates the alignment of the probe card to the dies, the positioning of the blackbodies, FPA image frame acquisition using IRXCAM, as well as data analysis and storage. Radiometric measurement precision has been validated by packaging dies measured by the automated probing system and re-measuring the SiTF and Noise using INO's pre-existing benchtop system.
Dufour, Denis G.; Topart, Patrice; Tremblay, Bruno; Julien, Christian; Martin, Louis; Vachon, Carl
Precise quantitation of PAIgG: A new radiometric microtechnique
We report the development of a radiometric assay for platelet-bound IgG that is both sensitive and quantitative. The assay utilized 96-well millititer plates incorporating a 0.2 microns filter membrane in the bottom. A 125I-labeled monoclonal antihuman IgG, as a secondary antibody, detected the platelet-bound human IgG. Since 5 x 10(6) platelets were used for each assay, tests for platelet-bound IgG can be performed on persons with severe thrombocytopenia. For the detection of circulating antiplatelet alloantibodies, as little as 10 microliters of platelet-free plasma per assay is required. Antiplatelet IgG was quantitated by using anti-PIA1 antibody that was purified with affinity and elution and DEAE chromatography. This purified antiplatelet antibody was labeled with 125I and was used to determine the binding ratio of secondary antibody to primary antibody. Under our standard conditions, this ratio was found to be stable at approximately 0.35 over the sensitivity range of the assay. The assay can detect approximately 200 molecules of human IgG per platelet (0.1 ng of secondary antibody bound per 5 x 10(6) platelets). It has a linear range from 0 to 7,000 molecules per platelet. Quantitation of anti-PIA1 binding for platelets stored for up to 6 months under refrigeration showed no change in number of PIA1 binding sites. Clinical studies showed that 18 of 19 ITP patients had an increased number of IgG molecules per platelet as did patients with malignancy and drug-induced immune thrombocytopenia. Patients who had received multiple platelet transfusions had antiplatelet antibody in their plasma. Normal amounts of PAIgG were observed in platelets and plasma of patients with nonimmune thrombocytopenia.
Schwartz, K.A.; Gauger, J.A.; Davis, J.M. (Michigan State Univ., East Lansing (USA))
Electrothermal radiometric detection of the semiconductor-to-metal-phase transition in single-crystal (TaSe/sub 4/)/sub 2/I
Electrothermal radiometry, a new radiometric technique for investigating phase transitions in semiconductors and metals, is described. Single crystals of (TaSe/sub 4/)/sub 2/I are heated by electric current pulses, and the thermal radiation of the samples is detected. The dependence of the electrothermal radiometry signal on the frequency and amplitude of the current pulses and on the temperature is discussed. The signal intensity is inversely proportional to the frequency. The static component of the temperature at the surface is obtained from the dependence on the current intensity. The temperature dependence is mostly determined by the change of the resistivity of the sample.
Pekker, S.; Eyring, E.M.
GPU-based high-precision real-time radiometric rendering for IR scene generation
NASA Astrophysics Data System (ADS)
Aiming at the problem that traditional infrared scene real-time radiometric rendering method leads to greater calculation error for securing real-time purpose, this article studies the IR rendering comprehensive optimization method, which secures real-time performance as well as calculation accuracy. Firstly, based on the effective average value principle, the spectrum coupling thermal emission and reflected radiations in the spectral radiometric equation are decomposed into physical quantities, and the spectral radiometric equation is improved to become a simpler calculation between "primer" radiance terms and effective average factors. Secondly, the parameter processing method is proposed to cope with the situation when index parameters of effective average factors exceed the maximum dimensionalities of graphics processing unit (GPU) look-up-table (LUT); and pre-calculation method is applied to promote the real-time evaluation efficiency of the physical quantities in the radiometric equation. Finally, concurrent computation of radiometric equation is achieved with GPU IR scene generation software and the precise and real-time rendering of three-dimensional IR scene is realized.
Huang, Xi; Zhang, Jianqi; Zhang, Shaoze; Wu, Xin
Radiometric Characterization Results for the IKONOS, Quickbird, and OrbView-3 Sensor
NASA Technical Reports Server (NTRS)
Radiometric calibration of commercial imaging satellite products is required to ensure that science and application communities better understand commercial imaging satellite properties. Inaccurate radiometric calibrations can lead to erroneous decisions and invalid conclusions and can limit intercomparisons with other systems. To address this calibration need, the NASA Applied Sciences Directorate (ASD) at Stennis Space Center established a commercial satellite imaging radiometric calibration team consisting of three independent groups: NASA ASD, the University of Arizona Remote Sensing Group, and South Dakota State University. Each group independently determined the absolute radiometric calibration coefficients of available high-spatial-resolution commercial 4-band multispectral products, in the visible though near-infrared spectrum, from GeoEye(tradeMark) (formerly SpaceImaging(Registered TradeMark)) IKONOS, DigitalGlobe(Regitered TradeMark) QuickBird, and GeoEye (formerly ORBIMAGE(Registered TradeMark) OrbView. Each team member employed some variant of reflectance-based vicarious calibration approach, requiring ground-based measurements coincident with image acquisitions and radiative transfer calculations. Several study sites throughout the United States that covered a significant portion of the sensor's dynamic range were employed. Satellite at-sensor radiance values were compared to those estimated by each independent team member to evaluate the sensor's radiometric accuracy. The combined results of this evaluation provide the user community with an independent assessment of these sensors' absolute calibration values.
Holekamp, Kara; Aaron, David; Thome, Kurtis
Dating jealousy among college students
In a study of dating jealousy, questionnaires were administered to 147 male and 189 female college students. Subjects were asked to rate how they would feel about their dating partner's behavior in five hypothetical situations designed to measure jealousy. Results indicate that females are more jealous than males over situations involving the partner spending time on a hobby or with
Gary L. Hansen
Surface Dating of Dynamic Landforms: Young Boulders on Aging Moraines
The dating of landforms is crucial to understanding the evolution, history, and stability of landscapes. Cosmogenic isotope analysis has recently been used to determine quantitative exposure ages for previously undatable landform surfaces. A pioneering application of this technique to date moraines illustrated its considerable potential but suggested a chronology partially inconsistent with existing geological data. Consideration of the dynamic nature
Bernard Hallet; Jaakko Putkonen
Color image processing for date quality evaluation
NASA Astrophysics Data System (ADS)
Many agricultural non-contact visual inspection applications use color image processing techniques because color is often a good indicator of product quality. Color evaluation is an essential step in the processing and inventory control of fruits and vegetables that directly affects profitability. Most color spaces such as RGB and HSV represent colors with three-dimensional data, which makes using color image processing a challenging task. Since most agricultural applications only require analysis on a predefined set or range of colors, mapping these relevant colors to a small number of indexes allows simple and efficient color image processing for quality evaluation. This paper presents a simple but efficient color mapping and image processing technique that is designed specifically for real-time quality evaluation of Medjool dates. In contrast with more complex color image processing techniques, the proposed color mapping method makes it easy for a human operator to specify and adjust color-preference settings for different color groups representing distinct quality levels. Using this color mapping technique, the color image is first converted to a color map that has one color index represents a color value for each pixel. Fruit maturity level is evaluated based on these color indices. A skin lamination threshold is then determined based on the fruit surface characteristics. This adaptive threshold is used to detect delaminated fruit skin and hence determine the fruit quality. The performance of this robust color grading technique has been used for real-time Medjool date grading.
Lee, Dah Jye; Archibald, James K.
Reconstructing level changes and assessing evidence for tectonic and glacial-rebound induced tilting of the Lake Wakatipu basin, New Zealand using novel techniques for correlating and dating paleoshorelines
NASA Astrophysics Data System (ADS)
Glacial-rebound signals have not previously been identified or isolated from tectonic processes in the New Zealand landscape. This contrasts with other parts of the world where glacial-unloading has caused tens to hundreds of meters of uplift and increased fault activity. The aim of this research was to quantify the magnitude and timing of post-glacial lake-level changes and deformation of the Lake Wakatipu basin, New Zealand. Abandoned shorelines up to 43 m above the modern water-level had previously been suggested to be tilted. Accurate measurement of the magnitude and timing of tilting would provide a unique attempt to extract a glacial-rebound signal from the tectonically-overprinted New Zealand landscape. Paleo-shoreline profiles were surveyed along the lake using GPS and existing air-borne LiDAR datasets. The shoreline profiles were correlated based on elevation and numerically cross-correlated to assess potential progressive offset. The results reveal negligible elevation differences, in conflict with previous suggestions of shoreline tilting. The timing of lake lowering was assessed with Schmidt hammer exposure-age and optically stimulated luminescence (OSL) dating of a flight of alluvial terraces directly correlated with the shorelines. The ages suggest formation of the lake by ~17.1 +/- 2.6 ka, which is assumed to be the approximate age for initial formation of the highest and most prominent preserved shoreline. Abandonment of this high-stand shoreline is thought to have commenced at ~12 ka when lake drainage switched to a new outlet, and was followed by gradual lowering (of about 20 m in 8-10 kyr). Lowering accelerated at about 2 ka, rapidly achieving 26-29 m of lowering before then reversing by 3-6 m to attain the present-day level. Glacial-rebound induced uplift or fault activity in the last 18 kyr has not been recorded by paleo-shorelines of Lake Wakatipu. We suggest that a glacial-isostatic signal is not present in the data because either glacial rebound occurred very quickly after ice retreat, or that any uplift was uniformly distributed over the length of the lake. These results invite investigation of other glaciated areas of New Zealand to explore whether this pattern is spatially and temporally consistent.
McColl, S. T.; Stahl, T. A.; Cook, S.
Field determination of optimal dates for the discrimination of invasive wetland plant species using derivative spectral analysis
Mapping invasive plant species in aquatic and terrestrial ecosystems helps to understand the causes of their progression, manage some of their negative consequences, and control them. In recent years, a variety of new remote-sensing techniques, like Derivative Spectral Analysis (DSA) of hyperspectral data, have been developed to facilitate this mapping. A number of questions related to these techniques remain to be addressed. This article attempts to answer one of these questions: Is the application of DSA optimal at certain times of the year? Field radiometric data gathered weekly during the summer of 1999 at selected field sites in upstate New York, populated with purple loosestrife (Lythrum salicaria L.), common reed (Phragmites australis (Cav.)) and cattail (Typha L.) are analyzed using DSA to differentiate among plant community types. First, second and higher-order derivatives of the reflectance spectra of nine field plots, varying in plant composition, are calculated and analyzed in detail to identify spectral ranges in which one or more community types have distinguishing features. On the basis of the occurrence and extent of these spectral ranges, experimental observations suggest that a satisfactory differentiation among community types was feasible on 30 August, when plants experienced characteristic phenological changes (transition from flowers to seed heads). Generally, dates in August appear optimal from the point of view of species differentiability and could be selected for image acquisitions. This observation, as well as the methodology adopted in this article, should provide a firm basis for the acquisition of hyperspectral imagery and for mapping the targeted species over a broad range of spatial scales. ?? 2005 American Society for Photogrammetry and Remote Sensing.
Laba, M.; Tsai, F.; Ogurcak, D.; Smith, S.; Richmond, M. E.
Radiometric survey of the triassic formations in the Haramon area using radon technique.
National Technical Information Service (NTIS)
A combination of radon measurements and gamma ray spectrometric survey was carried out over the black marly formation of the upper Triassic in the Haramon region, south west of syria. the geochemical characteristic of this marly formation were assumed to ...
Y. Jubeli M. al-Hilal A. Al-Ali
Global Positioning Radiometric Scanner System. Innovative Technology Summary Report
The US DOE continually seeks safer and more cost-effective technologies for use in decontamination and decommissioning (D&D) of nuclear facilities. To this end, the Deactivation and Decommissioning Focus Area (DDFA) of the DOE OST sponsors the Large Scale Demonstration and Deployment Projects (LSDDP). At these LSDDPs, developers and vendors of improved or innovative technologies showcase products that are potentially beneficial to the DOE projects and to others in the D&D community. Benefits sought include decreased health and safety risks to personnel and the environment, increased productivity, and decreased costs of operation. The Idaho National Engineering and Environmental Laboratory (INEEL) LSDDP generated a list of statements defining specific needs or problems where improved technology could be incorporated into ongoing D&D tasks. One of the stated needs was for developing technologies that would reduce costs and shorten D&D schedules by providing radiological characterizations to meet the free-release criteria. The Global Positioning Radiometric Scanner (GPRS system shown in Figure 1) utilizes a detection system; a portable computer, a differential global positioning system (d-gps), and a four wheel drive vehicle. Once the survey data has been collected, a software program called GeoSoft{trademark} generates a graphical representation of the radiological contamination extent. Baseline technology involves gridding the area and hand surveying each grid. This demonstration investigated the associated costs and the required time to evaluate the radiological characterization data from the GPRS with respect to the baseline technology. The GPRS system performs in-situ, real-time analyses to identify the extent of radiological contamination. Benefits expected from using the new innovative technology (GPRS) include: Reduced labor hours associated with performing the survey; Increased number of survey data points; Reduced exposure to radiation; Shortened D&D schedules; Reduced operating costs; Real time, in-situ radiological measurements; Visual representation of the extent of radiological contamination; and More accurate and reproducible survey results. This document contains information on the above-mentioned technology, including description, applicability, cost, and performance data.
Surface flux estimation using radiometric temperature: A dual-temperature-difference method to minimize measurement errors
NASA Astrophysics Data System (ADS)
Surface temperature serves as a key boundary condition that defines the partitioning of surface radiation into sensible and latent heat fluxes. Surface brightness temperature measurements from satellites offer the unique possibility of mapping surface heat fluxes at regional scales. Because uncertainties in satellite measurements of surface radiometric temperature arise from atmospheric corrections, surface emissivity, and instrument calibrations, a number of studies have found significant discrepancies between modeled and measured heat fluxes when using radiometric temperature. Recent research efforts have overcome these uncertainties and in addition have accounted for the difference between radiometric and aerodynamic temperature by considering soil and vegetative-canopy aerodynamic resistances. The major remaining obstacle to using satellite data for regional heat flux estimation is inadequate density of near-surface air temperature observations. In this paper we describe a simple, operational, double-difference approach for relating surface sensible heat flux to remote observations of surface brightness temperature, vegetative cover and type, and measurements of near-surface wind speed and air temperature from the synoptic weather network. A double difference of the time rate of change in radiometric and air temperature observations is related to heat flux. This double-difference approach reduces both the errors associated with deriving a radiometric temperature and with defining meteorological quantities at large scales. The scheme is simpler than other recent approaches because it requires minimal ground-based data and does not require modeling boundary layer development. The utility of this scheme is tested with ground-based radiometric temperature observations from several arid and subhumid climates with a wide range of vegetative cover and meteorological conditions.
Norman, J. M.; Kustas, W. P.; Prueger, J. H.; Diak, G. R.
Comparison of diverse methods for the correction of atmospheric effects on LANDSAT and SKYLAB images. [radiometric correction in Brazil
NASA Technical Reports Server (NTRS)
Earth's atmosphere reduces a sensors ability in currently discriminating targets. Using radiometric correction to reduce the atmospheric effects may improve considerably the performance of an automatic image interpreter. Several methods for radiometric correction from the open literature are compared leading to the development of an atmospheric correction system.
Parada, N. D. J. (principal investigator); Camara, G.; Dias, L. A. V.; Mascarenhas, N. D. D.; Desouza, R. C. M.; Pereira, A. E. C.
Radiometric homogenization of the color cryosection images from the VHP Lungs for 3D segmentation of blood vessels
This work deals with the problem of radiometric inhomogeneities found on the physical color images of the anatomical cryosections from the Visible Human Project (VHP) male body. Our goal is to extract very thin structures, like the blood vessel tree from the lungs. Current segmentation methods applied to VHP color images are disturbed by discontinuous, inter-slice radiometric variations; we thus
J M�rquez; F Schmitt
Geometric and radiometric performance evaluation methods for Marine Observation Satellite-1 (MOS-1) verification program (MVP)
NASA Astrophysics Data System (ADS)
The airborne verification experiment designed to develop algorithms for the data processing facility of MOS-1 and to assess geometric and radiometric performance evaluation methods for the MOS-1 verification program (MVP) is described. The geometric and radiometric performance evaluation methods described include the evaluation of the S/N and gain change effect, brooming evaluation, sensor alignment evaluation, and spatial resolution evaluation for the MESSR; the spatial resolution evaluation for the VTIR; and the S/N evaluation and spatial resolution evaluation for the MSR.
Maeda, K.; Azuma, Y.; Kojima, M.
Comparative Study of Radioimmunoassay Dates.
National Technical Information Service (NTIS)
The radioimmunoassay is frequently used in clinical chemistry for the concentration determination of several substances like hormones as thyrotropine and thyroxine. In this experiment the dates of tyroxine radioimmunoassay are processed by three methods: ...
R. Venegas Sanchez
NSDL National Science Digital Library
1) How are zircons formed? 2) Which of the following statements describes relative geologic dating? a) the Triceratops and Tyrannosaurus rex went extinct at the same time b) dinosaurs came later than horseshoe ...
Guertin, Laura
Towards Luminescence Dating Of Mosaic Glass
NASA Astrophysics Data System (ADS)
The possibility of dating archaeological glass by means of luminescent techniques has been investigated in recent years, despite the difficulties of this application, mainly linked to the amorphous structure of the material. We focused in particular on mosaic glass, after the encouraging results obtained on byzantine and medieval samples. Further studies were devoted to the comprehension of the luminescent mechanisms in silica glasses, and to the investigation of the relationships between luminescence, colouring or opacifier ions and crystalline phase of the vitreous matrix. The results of a study on the dosimetric characteristics of thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) of a few medieval blue-green mosaic glasses from the San Lorenzo church (Milan) are presented, and the experimental protocols established to identify their suitability for dating are discussed.
Galli, A.; Martini, M.; Sibila, E.; Villa, I.
Radiometric age of the snout ice of Nehnar glacier
The surface ice taken from the snout of the Nehnar glacier (Kashmir) in western Himalaya has been dated using radioisotopes32Si and210Pb to be 500 years. Based on the age distribution of ice and the expected activity of32Si in the fallout, the average rate of glacier movement over a period of the last few centuries is estimated to be about 6
N. Bhandari; D. I. Bhatt; V N Nijampurkar; R K Singh; D. Srivatsava; C P Vohra
Radiometric Ages From ODP Leg 197 Drilling Along the Emperor Seamount Chain
NASA Astrophysics Data System (ADS)
The Hawaiian-Emperor Seamount chain is the "type" example of an age-progressive, hotspot-generated intraplate volcanic lineament. However, our current knowledge of the age distribution within this province is based on radiometric ages determined several decades ago. Improvements in instrumentation, sample preparation methods and new material obtained by recent drilling warrant a re-examination of the age relations among the older Hawaiian volcanoes. We report new age determinations (40Ar-39Ar incremental heating method) on whole rocks and feldspar separates from Detroit (Sites 1203 and 1204), Nintoku (Site 1205) and Koko (Site 1206) seamounts in the Emperor chain, recovered by drilling during ODP Leg 197. Only normal magnetic polarity was observed at Sites 1203 and 1204, and biostratigraphic data assigned ages of 75-76 Ma (nanofossil zone cc22) to sediments interbedded with lava flows. Plateaus in incremental heating age spectra give a mean age for Site 1203 of 75.3 +/- 1.0 Ma (relative to biotite monitor FCT-3 at 28.04 Ma; all errors are 2s). Site 1204 lavas have produced only discordant data so far (5 samples). These new ages are significantly younger than the 81 Ma age reported by Keller et al. (1995) for Site 884 (reverse polarity lavas) on the northeastern flank of Detroit seamount, and suggest that this complex may include several large volcanoes. All volcanic units at Site 1205 exhibit reverse polarity magnetization and biostratigraphic data place the lowermost sediments close to the Eocene-Paleocene boundary. Six plateau ages from lava flows spanning the 283m cored section give a mean age of 55.6 +/- 0.2 Ma (range: 55.2-56.4 Ma), corresponding to Chron 24r. Drilling at Site 1206 intersected a 278m N-R-N sequence of lava flows. Six plateau ages give a mean age of 49.1 +/- 0.2 Ma (range: 47.9-49.7 Ma), corresponding to the Chron 21n-21r-22n sequence. Deep penetration at the three seamounts and shipboard geochemical data suggest that the main shield-post shield stages of volcano development have been sampled at each location and dated. While the overall trend is decreasing volcano age from N to S along the Emperor Seamounts, there appear to be important departures from the earlier modeled simple linear age progression.
Duncan, R. A.; Huard, J.
Radiometric ages for basement rocks from the Emperor Seamounts, ODP Leg 197
NASA Astrophysics Data System (ADS)
The Hawaiian-Emperor seamount chain is the "type" example of an age-progressive, hot spot-generated intraplate volcanic lineament. However, our current knowledge of the age distribution within this province is based largely on radiometric ages determined several decades ago. Improvements in instrumentation, sample preparation methods, and new material obtained by recent drilling warrant a reexamination of the age relations among the older Hawaiian volcanoes. We report new age determinations (40Ar-39Ar incremental heating method) on whole rocks and feldspar separates from Detroit (Sites 1203 and 1204), Nintoku (Site 1205), and Koko (Site 1206) Seamounts (Ocean Drilling Program (ODP) Leg 197) and Meiji Seamount (Deep Sea Drilling Project (DSDP) Leg 19, Site 192). Plateaus in incremental heating age spectra for Site 1203 lava flows give a mean age of 75.8 � 0.6 (2?) Ma, which is consistent with the normal magnetic polarity directions observed and biostratigraphic age assignments. Site 1204 lavas produced discordant spectra, indicating Ar loss by reheating and K mobilization. Six plateau ages from lava flows at Site 1205 give a mean age of 55.6 � 0.2 Ma, corresponding to Chron 24r. Drilling at Site 1206 intersected a N-R-N magnetic polarity sequence of lava flows, from which six plateau ages give a mean age of 49.1 � 0.2 Ma, corresponding to the Chron 21n-22r-22n sequence. Plateau ages from two feldspar separates and one lava from DSDP Site 192 range from 34 to 41 Ma, significantly younger than the Cretaceous age of overlying sediments, which we relate to postcrystallization K mobilization. Combined with new dating results from Suiko Seamount (DSDP Site 433) and volcanoes near the prominent bend in the lineament [, 2002], the overall trend is increasing volcano age from south to north along the Emperor Seamounts, consistent with the hot spot model. However, there appear to be important departures from the earlier modeled simple linear age progression, which we relate to changes in Pacific plate motion and the rate of southward motion of the Hawaiian hot spot.
Duncan, Robert A.; Keller, Randall A.
A Sounding Rocket Mission Concept to Acquire High-Resolution Radiometric Spectra Spanning the 9 nm - 31 nm Wavelength Range
NASA Technical Reports Server (NTRS)
When studying Solar Extreme Ultraviolet (EUV) emissions, both single-wavelength, two- dimensional (2D) spectroheliograms and multi-wavelength, one-dimensional (1D) line spectra are important, especially for a thorough understanding of the complex processes in the solar magnetized plasma from the base of the chromosphere through the corona. 2D image data are required for a detailed study of spatial structures, whereas radiometric (i.e., spectral) data provide information on relevant atomic excitation/ionization state densities (and thus temperature). Using both imaging and radiometric techniques, several satellite missions presently study solar dynamics in the EUV, including the Solar Dynamics Observatory (SDO), Hinode, and the Solar-Terrestrial Relations Observatory (STEREO). The EUV wavelengths of interest typically span 9 nm to 31 nm, with the shorter wavelengths being associated with the hottest features (e.g., intense flares and bright points) and the longer wavelengths associated with cooler features (e.g., coronal holes and filaments). Because the optical components of satellite instruments degrade over time, it is not uncommon to conduct sounding rocket underflights for calibration purposes. The authors have designed a radiometric sounding rocket payload that could serve as both a calibration underflight for and a complementary scientific mission to the upcoming Solar Ultraviolet Imager (SUVI) mission aboard the GOES-R satellite (scheduled for a 2015 launch). The challenge to provide quality radiometric line spectra over the 9-31 nm range covered by SUVI was driven by the multilayer coatings required to make the optical components, including mirrors and gratings, reflective over the entire range. Typically, these multilayers provide useful EUV reflectances over bandwidths of a few nm. Our solution to this problem was to employ a three-telescope system in which the optical components were coated with multilayers that spanned three wavelength ranges to cover the three pairs of SUVI bands. The complete system was designed to fit within the Black Brandt-IX 22.-diameter payload skin envelope. The basic optical path is that of a simple parabolic telescope in which EUV light is focused onto a slit and shutter assembly and imaged onto a normal-incidence diffraction grating, which then disperses the light onto a 2048 2048 CCD sensor. The CCD thus records 1D spatial information along one axis and spectral information along the other. The slit spans 40 arc-minutes in length, thus covering a solar diameter out to +/- 1.3 solar radii. Our operations concept includes imaging at three distinct positions: the north-south meridian, the northeast-southwest diagonal, and real-time pointing at an active region. Six 10-second images will be obtained at each position. Fine pointing is provided by the SPARCS-VII attitude control system typically employed on Black Brandt solar missions. Both before and after launch, all three telescopes will be calibrated with the EUV line emission source and monochromater system at NASA's Stray Light Facility at Marshall Spaceflight Center. Details of the payload design, operations concept, and data application will be presented.
Krause, L. Habash; Cirtain, Jonathan; McGuirck, Michael; Pavelitz, Steven; Weber, Ed.; Winebarger, Amy
Ar-Ar Dating of Martian Meteorite, Dhofar 378: An Early Shock Event?
NASA Technical Reports Server (NTRS)
Martian meteorite, Dhofar 378 (Dho378) is a basaltic shergottite from Oman, weighing 15 g, and possessing a black fusion crust. Chemical similarities between Dho378 and the Los Angeles 001 shergottite suggests that they might have derived from the same Mars locale. The plagioclase in other shergottites has been converted to maskelenite by shock, but Dho378 apparently experienced even more intense shock heating, estimated at 55-75 GPa. Dho378 feldspar (approximately 43 modal %) melted, partially flowed and vesiculated, and then partially recrystallized. Areas of feldspathic glass are appreciably enriched in K, whereas individual plagioclases show a range in the Or/An ratio of approximately 0.18-0.017. Radiometric dating of martian shergottites indicate variable formation times of 160-475 Myr, whereas cosmic ray exposure (CRE) ages of shergottites indicate most were ejected from Mars within the past few Myr. Most determined Ar-39-Ar-40 ages of shergottites appear older than other radiometric ages because of the presence of large amounts of martian atmosphere or interior Ar-40. Among all types of meteorites and returned lunar rocks, the impact event that initiated the CRE age very rarely reset the Ar-Ar age. This is because a minimum time and temperature is required to facilitate Ar diffusion loss. It is generally assumed that the shock-texture characteristics in martian meteorites were produced by the impact events that ejected the rocks from Mars, although the time of these shock events (as opposed to CRE ages) are not directly dated. Here we report Ar-39-Ar-40 dating of Dho378 plagioclase. We suggest that the determined age dates the intense shock heating event this meteorite experienced, but that it was not the impact that initiated the CRE age.
Park, J.; Bogard, D. D.
Surface and aerosol models for use in radiative transfer codes. [for radiometric calibration of Landsat-5 Thematic Mapper (TM)
NASA Technical Reports Server (NTRS)
Absolute reflectance-based radiometric calibrations of Landsat-5 Thematic Mapper (TM) are improved with the inclusion of a method to invert optical-depth measurements to obtain aerosol-particle size distributions, and a non-Lambertian surface reflectance model. The inverted size distributions can predict radiances varying from the previously assumed jungian distributions by as much as 5 percent, though the reduction in the estimated error is less than one percent. Comparison with measured diffuse-to-global ratios show that neither distribution consistently predicts the ratio accurately, and this is shown to be a large contributor to calibration uncertainties. An empirical model for the surface reflectance of White Sands, using a two-degree polynomial fit as a function of scattering angle, was employed. The model reduced estimated errors in radiance predictions by up to one percent. Satellite calibrations dating from October, 1984 were reprocessed using the improved methods and linear estimations of satellite counts per unit radiance versus time since launch were determined which showed a decrease over time for the first four bands.
Hart, Quinn J.
Airborne lidar and radiometric observations of PBL- and low clouds
NASA Technical Reports Server (NTRS)
Boundary layer- and low altitude clouds over open ocean and continent areas have been studied during several field campaigns since mid-1990 using the French airborne backscatter lidar LEANDRE in conjunction with on-board IR and visible radiometers. LEANDRE is an automatic system, and a modification of the instrumental parameters, when airborne, is computer controlled through an operator keyboard. The vertical range squared lidar signals and instrument status are displayed in real time on two dedicated monitors. The lidar is used either down- or up-looking while the aircraft is flying above or below clouds. A switching of the viewing configuration takes about a minute. The lidar measurements provide a high resolution description of cloud morphology and holes in cloud layers. The flights were conducted during various meteorological conditions on single or multilayer stratocumulus and cumulus decks. Analysis on a single shot basis of cloud top (or bottom) altitude and a plot of the corresponding histogram allows one to determine a probability density function (PDF). The preliminary results show the PDFs for cloud top are not Gaussian and symmetric about the mean value. The skewness varies with atmospheric conditions. An example of results recorded over the Atlantic ocean near Biarritz is displayed, showing: (1) the range squared lidar signals as a function of time (here 100 s corresponds to about 8 km, 60 shots are averaged on horizontal); the Planetary Boundary Layer (PBL) - up to 600 m - is observed at the beginning of the leg as well as on surface returns, giving an indication of the porosity; (2) the cloud top altitude variation between 2.4 to 2.8 km during the 150 to 320 s section; and (3) the corresponding PDF. Similar results are obtained on stratocumulus over land. Single shot measurements can be used also to determine an optical porosity at a small scale as well as a fractional cloudiness at a larger scale. A comparison of cloud top altitude retrieved from lidar and narrowbeam IR radiometer is conducted to study the scale integration problem. A good agreement within less than 100 m relies on spatial uniformity and an optically thick layer. In the presence of holes, a discrepancy is observed. This is illustrated in figure 2, displaying as a function of time (1) the lidar signals; (2) the target temperature (either clouds or sea surface) retreived from a narrowbeam IR radiometer, 17 C is the sea surface temperature on that day; and (3) the visible flux, linked to cloud albedo, measured by a pyranometer. In preparation of ASTEX, down- and up-looking measurements where conducted on stratocumulus clouds over the Atlantic Ocean near Quimper in Brittany. Depending on the flight pattern orientation with respect to the wind, the top and bottom cloud morphologies are different. Preliminary results are given on cloud morphology, cloud top PDFs, optical porosity, fractional cloudiness, and comparison of lidar and radiometric measurements.
Flamant, P. H.; Valentin, R.; Pelon, J.
Offset reflector with horn feed array, used as an experimental sensor for radiometric measurements
A sensor consisting of a single offset reflector antenna with five beams for radiometric measurements with multiple receivers is presented. The design procedure and the arrangement of the feeds is described. A procedure for the exact adjustment of the reflector in relation to the feeds is outlined. The horn antenna was positioned for linear polarization so as to place the
H. J. Steiner
Offset-reflector with horn feed array as an experimental sensor for radiometric measurements
A sensor consisting of a single offset reflector antenna with five beams for radiometric measurements with multiple receivers is presented. The design procedure and the arrangement of the feeds is described. A procedure for the exact adjustment of the reflector in relation to the feeds is outlined. The horn antenna was positioned for linear polarization so as to place the
H. J. Steiner
System design and operation of a radiometric lens/camera system
NASA Astrophysics Data System (ADS)
Diversified Optical Products has designed an integrated lens, blackbody reference sources, and source control electronics for a mid-range IR Radiometric lens/staring focal plane array system. The purpose of the system is to be able to accurately correlate objects within the field of view of the system to two known, calibrated, and controllable blackbody sources also within the field of view. The two internal blackbody sources are thermoelectric cooler based, and their output is optically relayed to an internal image plane of the lens. The optical system also incorporates a neutral density filter wheel which attenuates the scene radiance so that both the blackbodies and the scene radiance can be brought into the dynamic range of the focal plane array. The goal of the design effort was to manufacture a highly accurate, field portable radiometric instrument. The specific design areas which where focused upon were: matching the optical design of the lens system with the camera design; controlling the radiometric properties of the optics, optical design requirements for the projection of the blackbody sources within the system field of view; and calibration requirements and methods for the total radiometric system.
Everett, Jonathan E.
On certain radiometric effects during the partial solar eclipse of February 25, 1952
Summary In this paper we discuss some interesting results of radiometric measurements carried out with a thermopile pyrheliometer and direct reading Gorczynski solarimeter during the eclipse of February 25, 1952, which was partial in Greece, as compared to similar measurements made on the two days preceding the eclipse, under identical meteorological conditions and with a sky of uniform and exceptional
W. N. Abbott
On certain radiometric effects during the partial solar eclipse of February 25, 1952
In this paper we discuss some interesting results of radiometric measurements carried out with a thermopile pyrheliometer and direct reading Gorczynski solarimeter during the eclipse of February 25, 1952, which was partial in Greece, as compared to similar measurements made on the two days preceding the eclipse, under identical meteorological conditions and with a sky of uniform and exceptional purity.
W. N. Abbott
Determination of the microbolometric FPA's responsivity with imaging system's radiometric considerations
NASA Astrophysics Data System (ADS)
Thermal imagers and used therein infrared array sensors are subject to calibration procedure and evaluation of their voltage sensitivity on incident radiation during manufacturing process. The calibration procedure is especially important in so-called radiometric cameras, where accurate radiometric quantities, given in physical units, are of concern. Even though non-radiometric cameras are not expected to stand up to such elevated standards, it is still important, that the image faithfully represents temperature variations across the scene. Detectors used in thermal camera are illuminated by infrared radiation transmitted through an infrared transmitting optical system. Often an optical system, when exposed to uniform Lambertian source forms a non-uniform irradiation distribution in its image plane. In order to be able to carry out an accurate non-uniformity correction it is essential to correctly predict irradiation distribution from a uniform source. In the article a non-uniformity correction method has been presented, that takes into account optical system's radiometry. Predictions of the irradiation distribution have been confronted with measured irradiance values. Presented radiometric model allows fast and accurate non-uniformity correction to be carried out.
Gogler, Slawomir; Bieszczad, Grzegorz; Krupinski, Michal
First approach for on-ground radiometric characterization of the new infrared sensor technology camera
NASA Astrophysics Data System (ADS)
The aim is to present a first approach for the on-ground radiometric characterization of the new infrared sensor technology (NIRST) instrument. NIRST is an infrared radiometer on board the SAC-D/Aquarius mission, launched on June 10, 2011. It is composed of a middle-wave infrared and a long-wave infrared camera, with three arrays of 512 microbolometers each, and has also a pointing Be mirror. In order to perform the on-ground radiometric characterization, several measurements are taken using blackbody sources. Aiming to obtain a set of absolute radiometric coefficients for each pixel of each microbolometer array, relating digital numbers and brightness temperature or its equivalent in radiated power, polynomial fits are performed. Interpixel characterization to obtain relative calibration coefficients is also performed, relating the counts of an arbitrary pixel to those of a reference pixel. The choice of polynomial order for both absolute and relative calibration functions, as well as the election of reference pixels, are analyzed. Finally, a pointing angle characterization is performed. This approach leads to high polynomial orders for both absolute and relative calibrations, indicating that a new approach for NIRST radiometric characterization is required to catch-up the nonlinearity.
Ganopol, Abigail; Marchese, Linda; Marraco, Hugo
Research on methods of spectral calibration and radiometric calibration of the windowing Fourier transform imaging spectrometer
NASA Astrophysics Data System (ADS)
Spectral calibration and radiometric calibration is an important part in the data processing of the windowing Fourier transform imaging spectrometer, it can ensure that the spectral curve output from spectrometer are more closely to target spectrum. The main idea of spectral calibration is using a monochromatic source whose wavelength is known, in the same way, radiometric calibration can be achieved by using radiation source whose radiation characteristic is known. In this paper, we propose a set of methods of spectral calibration and radiometric calibration. In order to carry out spectral calibration, we use monocharomator to scan several sample points near the position of every spectral channel of imaging spectrometer, and then we employ Gaussian fitting function to determine the central wavelength and bandwidth of every spectral channel. In order to carry out radiometric calibration, we employ panchromatic light source and integrating sphere, at the position of every spectral channel of imaging spectrometer, we measure the response ability of spectrometer to radiation. The calibration accuracy is carefully analyzed. Experimental results show that calibration accuracy meet the given requirements.
Zhang, Lei; Gao, Jiao Bo; Zhao, Yu Jie; Luo, Yan Ling; Xiao, Xiang Guo; Zhang, Fang