text:
Office of Scientific and Technical Information
Properties of tropical convection observed by ARM millimeter-radars
NLE Websites -- All DOE Office Websites (Extended Search)
Properties of tropical convection observed by ARM millimeter-radars Properties of tropical convection observed by ARM millimeter-radars Haynes, John Colorado State University Stephens, Graeme Colorado State University Category: Cloud Properties The results of an analysis of tropical cloud systems observed from a variety of vertically pointing radar systems are described. In particular, observations taken during five years of operation of the ARM millimeter wavelength radar system (MMCR) at Manus Island in the Tropical West Pacific region are characterized into cloud classes according to the radar reflectivity structures of these cloud systems, associated rainfall, and surface radiative properties. These observations of cloud properties are composited with respect to various phases of the Madden Julian Oscillation, which is a dominant mode of variability at Manus Island. A method of better
Physical Characterization of Tropical Oceanic Convection Observed in KWAJEX
Science Conference Proceedings (OSTI)
The Tropical Rainfall Measuring Mission (TRMM) Kwajalein Experiment (KWAJEX) was designed to obtain an empirical physical characterization of precipitating convective clouds over the tropical ocean. Coordinated datasets were collected by three ...
Sandra E. Yuter; Robert A. Houze Jr.; Eric A. Smith; Thomas T. Wilheit; Edward Zipser
Observed Evolution of Tropical Deep Convective Events and Their Environment
Using a compositing technique, the temporal progression of tropical convective systems and the mean atmospheric state in their vicinity is constructed from a time series of geostationary satellite and operational rawinsonde data. The technique ...
Steven C. Sherwood; Ralph Wahrlich
Stochastic behavior of tropical convection in observations and a multicloud model
The aim for a more accurate representation of tropical convection in global circulation models is a long-standing issue. Here, the relationships between large- and convective scales in observations and a Stochastic Multicloud Model (SMCM) to ...
Karsten Peters; Christian Jakob; Laura Davies; Boualem Khouider; Andrew J. Majda
Regional Variability in Tropical Convection: Observations from TRMM
Observation of the vertical profile of precipitation over the global Tropics is a key objective of the Tropical Rainfall Measuring Mission (TRMM) because this information is central to obtaining vertical profiles of latent heating. This study ...
Walter A. Petersen; Steven A. Rutledge
Passive Microwave Observations of the Stratiform Regions of Two Tropical Oceanic Mesoscale Convective Systems
High-resolution passive microwave observations within the stratiform regions of two different tropical oceanic mesoscale convective systems are investigated in detail. The observations were obtained from the Advanced Microwave Precipitation ...
Gary McGaughey; Edward J. Zipser
Composite Life Cycle of Maritime Tropical Mesoscale Convective Systems in Scatterometer and Microwave Satellite Observations
This study examines scatterometer-observed surface wind divergence and vorticity, along with precipitable water (PW), across the life cycle of tropical maritime mesoscale convective systems (MCSs) as resolved in 0.5� data. Simple composites were ...
Brian Mapes; Ralph Milliff; Jan Morzel
Properties of Tropical Convection Observed by Millimeter-Wave Radar Systems
This paper describes the results of analysis of over 825 000 profiles of millimeter-wave radar (MWR) reflectivities primarily collected by zenith-pointing surface radars observing tropical convection associated with various phases of activity of ...
Graeme L. Stephens; Norman B. Wood
High-Resolution Passive Microwave Observations of Convective Systems over the Tropical Pacific Ocean
This paper presents high-resolution passive microwave measurements obtained in the western Pacific warm pool region. These measurements represent the most comprehensive such observations of convection over the tropical oceans to date, and were ...
Gary McGaughey; Edward J. Zipser; Roy W. Spencer; Robbie E. Hood
Convective Impact on Temperatures Observed near the Tropical Tropopause
Observed temperature trends and interannual variations near the tropical tropopause suggest that temperatures up to the cold point are controlled by the troposphere, but some models indicate otherwise. Here, previous investigations of thermal ...
Steven C. Sherwood; Takeshi Horinouchi; Heidi A. Zeleznik
Convective Activity over Africa and the Tropical Atlantic Inferred from 20 Years of Geostationary Meteosat Infrared Observations
A 20-yr (1986�2005) time series of Meteosat Visible and Infrared Imager (MVIRI) geostationary infrared observations was used to study deep convection over Africa and the tropical Atlantic. The 20-yr time period is covered by six consecutive ...
Ralf Bennartz; Marc Schroeder
Variability of Graupel and Snow Observed in Tropical Oceanic Convection by Aircraft during TRMM KWAJEX
Empirical characterization of graupel and snow in precipitating tropical convective clouds is important for refining satellite precipitation retrieval algorithms and cloud-resolving and radiative transfer models. Microphysics data for this ...
Ellen M. Sukovich; David E. Kingsmill; Sandra E. Yuter
Cloud and Radiative Characteristics of Tropical Deep Convective Systems in Extended Cloud Objects from CERES Observations
The physical and radiative properties of tropical deep convective systems for the period from January to August 1998 are examined with the use of Clouds and the Earth�s Radiant Energy System Single-Scanner Footprint (SSF) data from the Tropical ...
Zachary A. Eitzen; Kuan-Man Xu; Takmeng Wong
Observations of Lightning in Convective Supercells within Tropical Storms and Hurricanes
Cloud-to-ground (CG) lightning observations from land-based lightning detection networks now allow monitoring this component of the electrical structure of tropical storms and hurricanes within a few hundred kilometers of the United States ...
Walter A. Lyons; Cecil S. Keen
Satellite Observations of Variations in Tropical Cyclone Convection Caused by Upper-Tropospheric Troughs
The mutual adjustment between upper-tropospheric troughs and the structure of western Atlantic Tropical Cyclones Florence (1988) and Irene (1981) are analyzed using satellite and in situ data. Satellite-observed tracers (e.g., cirrus clouds, ...
Edward B. Rodgers; Simon W. Chang; John Stout; Joseph Steranka; Jainn-Jong Shi
Tropical cyclone size in observations and in radiative-convective equilibrium
E-Print Network (OSTI)
Tropical cyclone size remains an unsolved problem in tropical meteorology, yet size plays a significant role in the damage caused by tropical cyclones due to wind, storm surge, and inland freshwater flooding. This work ...
Chavas, Daniel Robert
Tropical Convective Variability as 1/f Noise
Evidence is presented that the tropical convective variability behaves as 1/f noise for a 1�30-day period. This behavior is shown by analyzing the time series of convective available potential energy, which measures the degree of convective ...
Jun-Ichi Yano; Klaus Fraedrich; Richard Blender
The Effect of Environmental Conditions on Tropical Deep Convective Systems Observed from the TRMM Satellite
This study uses measurements of radiation and cloud properties taken between January and August 1998 by three Tropical Rainfall Measuring Mission (TRMM) instruments, the Clouds and the Earth�s Radiant Energy System (CERES) scanner, the TRMM ...
Bing Lin; Bruce A. Wielicki; Patrick Minnis; Lin Chambers; Kuan-Man Xu; Yongxiang Hu; Alice Fan
On the Relationship between Tropical Convection and Sea Surface Temperature
Tropical observations show convective activity increasing sharply above sea surface temperatures (SSTs) of around 26�C and then decreasing as the SST exceeds 30�C, with maximum observed SSTs of around 32�C.Although some aspects of this ...
Adrian M. Tompkins
Deep Convective System Evolution over Africa and the Tropical Atlantic
In the tropical African and neighboring Atlantic region there is a strong contrast in the properties of deep convection between land and ocean. Here, satellite radar observations are used to produce a composite picture of the life cycle of ...
Joanna M. Futyan; Anthony D. Del Genio
Climatic Regimes of Tropical Convection and Rainfall
Annual distribution and phase propagation of tropical convection are delineated using harmonic and amplitude-phase characteristics analysis of climatological pentad mean outgoing longwave radiation and monthly frequencies of highly reflective ...
Bin Wang
Tropical observability and predictability
Many studies have investigated tropical data assimilation in the context of global models or specifically for tropical cyclones, but relatively few have focused on the mesoscale predictability and observability of the ...
Whitcomb, Timothy Robert
Characteristics of Deep Tropical and Subtropical Convection from Nadir-Viewing High-Altitude Airborne Doppler Radar
This paper presents observations of deep convection characteristics in the tropics and subtropics that have been classified into four categories: tropical cyclone, oceanic, land, and sea breeze. Vertical velocities in the convection were derived ...
Gerald M. Heymsfield; Lin Tian; Andrew J. Heymsfield; Lihua Li; Stephen Guimond
A Model of Rossby Waves Linked to Submonthly Convection over the Eastern Tropical Pacific
Equatorward-propagating wave trains in the upper troposphere are observed to be associated with deep convection over the eastern tropical Pacific on the submonthly timescale during northern winter. The convection occurs in the regions of ascent ...
Adrian J. Matthews; George N. Kiladis
Polarization diversity for millimeter space-borne Doppler radars: an answer for observing deep convection?
Spaceborne Doppler radars have the potential to provide key missing observations of convective vertical air motions especially over the tropical oceans. Such measurements can improve our understanding of the role of tropical convection in vertical ...
Alessandro Battaglia; Simone Tanelli; Pavlos Kollias
Deep Convective Systems Observed by A-Train in the Tropical Indo-Pacific Region Affected by the MJO
In the Indo-Pacific region, mesoscale convective systems (MCSs) occur in a pattern consistent with the eastward propagation of the large-scale convective envelope of the Madden�Julian oscillation (MJO). MCSs are major contributors to the total ...
Jian Yuan; Robert A. Houze Jr.
Convective Mixing near the Tropical Tropopause: Insights from Seasonal Variations
It has been suggested that convection remains important in the budget of water vapor up to the tropical tropopause or even higher. But observed seasonal variations of CO2 and water vapor in the lower stratosphere, and their timing, call the ...
Steven C. Sherwood; Andrew E. Dessler
ARM - Field Campaign - Year of Tropical Convection (YOTC)
govCampaignsYear of Tropical Convection (YOTC) govCampaignsYear of Tropical Convection (YOTC) Campaign Links Year of Tropical Convection Website Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Year of Tropical Convection (YOTC) 2008.05.01 - 2010.04.30 Lead Scientist : Sally McFarlane Description Example of a sonde profile available from the ARM Archive The realistic representation of tropical convection in global atmospheric models is a long-standing challenge for weather and global climate models. The lack of fundamental knowledge in this area causes difficulties in modeling and predicting prominent phenomena of the tropical atmosphere such as the inter-tropical convergence zone (ITCZ), El-Nino/Southern Oscillation (ENSO), monsoons, the Madden-Julian Oscillation (MJO), tropical cyclones,
Microphysical Observations of Tropical Clouds
The results from airborne in situ sampling of convective tropical storms in the Amazon and Kwajalein are presented. Three cases from the Amazon and two from Kwajalein are compared and provide examples of the much larger dataset that was obtained ...
Jeffrey L. Stith; James E. Dye; Aaron Bansemer; Andrew J. Heymsfield; Cedric A. Grainger; Walter A. Petersen; Robert Cifelli
Propagating and Standing Components of the Intraseasonal Oscillationin Tropical Convection
Two questions related to the intraseasonal variability of tropical convection and circulation remain controversial. 1) To what degree is the convective component of the Madden�Julian oscillation (MJO) a standing oscillation? 2) Is the eastward ...
Chidong Zhang; Harry H. Hendon
Modeling Study of a Tropical Squall-Type Convective Line
A multidimensional and time-dependent cloud scale model is used to investigate the dynamic and micro-physical processes associated with convective and stratiform regions within a tropical squall-type convective line. The evolution of the total ...
Wei-Kuo Tao; Joanne Simpson
Convective Momentum Transport over the Tropical Pacific: Budget Estimates
ECMWF and NCEP�NCAR reanalyses are used to calculate convective momentum transport (CMT) as a momentum budget residual over several tropical oceanic convective regions, including the TOGA COARE Intensive Flux Array (IFA). Sources of uncertainty ...
Matthew T. Carr; Christopher S. Bretherton
The Tropical Convective Spectrum. Part I: Archetypal Vertical Structures
A taxonomy of tropical convective and stratiform vertical structures is constructed through cluster analysis of 3 yr of Tropical Rainfall Measuring Mission (TRMM) �warm-season� (surface temperature greater than 10�C) precipitation radar (PR) ...
Dennis J. Boccippio; Walter A. Petersen; Daniel J. Cecil
Convective Precursors and Predictability in the Tropical Western Pacific
Conditions leading to convective outbreak in the Tropics are investigated by multivariate analysis of sounding and satellite data from the tropical western Pacific area. Circumstances that make the prediction problem difficult are discussed and ...
Steven C. Sherwood
The Effect of Horizontal Pressure Gradients on the Momentum Transport in Tropical Convective Lines. Part II: Lagrangian Calculations
The movement of a set of Lagrangian parcels in the two-dimensional pressure field associated with a tropical convective line is considered. The results are compared with observational characteristics of GATE quasi-two-dimensional convective ...
Maria Flatau; Duane E. Stevens
A Simple Multicloud Parameterization for Convectively Coupled Tropical Waves. Part II: Nonlinear Simulations
Observations in the Tropics point to the important role of three cloud types, congestus, stratiform, and deep convective clouds, besides ubiquitous shallow boundary layer clouds for both the climatology and large-scale organized anomalies such as ...
Boualem Khouider; Andrew J. Majda
A Test of the Simulation of Tropical Convective Cloudiness by a Cloud-Resolving Model
A methodology is described for testing the simulation of tropical convective clouds by models through comparison with observations of clouds and precipitation from earth-orbiting satellites. Clouds are divided into categories that represent ...
Mario A. Lopez; Dennis L. Hartmann; Peter N. Blossey; Robert Wood; Christopher S. Bretherton; Terence L. Kubar
The �Year� of Tropical Convection (May 2008�April 2010): Climate Variability and Weather Highlights
The representation of tropical convection remains a serious challenge to the skillfulness of our weather and climate prediction systems. To address this challenge, the World Climate Research Programme (WCRP) and The Observing System Research and ...
Duane E. Waliser; Mitchell W. Moncrieff; David Burridge; Andreas H. Fink; Dave Gochis; B. N. Goswami; Bin Guan; Patrick Harr; Julian Heming; Huang-Hsuing Hsu; Christian Jakob; Matt Janiga; Richard Johnson; Sarah Jones; Peter Knippertz; Jose Marengo; Hanh Nguyen; Mick Pope; Yolande Serra; Chris Thorncroft; Matthew Wheeler; Robert Wood; Sandra Yuter
Climatic regimes of tropical convection and rainfall
SciTech Connect
Annual distribution and phase propagation of tropical convection are delineated using harmonic and amplitude-phase characteristics analysis of climatological pentad mean outgoing longwave radiation and monthly frequencies of highly reflective cloud. An annual eastward propagation of peak rainy season along the equator from the central Indian Ocean (60[degrees]E) to Arafura Sea (130[degrees]E) is revealed. This indicates a transition from the withdrawal of the Indian summer monsoon to the onset of the Australian summer monsoon. Significant bimodal variations are found around major summer monsoon regions. These variations originate from the interference of two adjacent regimes. The convergence zones over the eastern North Pacific, the South Pacific, and the southwest Indian Ocean are identified as a marine monsoon regime that is characterized by a unimodal variation with a concentrated summer rainfall associated with the development of surface westerlies equatorward of a monsoon trough. Conversely, the central North Pacific and North Atlantic convergence zones between persistent northeast and southeast trades are classified as trade-wind convergence zones; which differ from the marine monsoon regime by their persistent rainy season and characteristic bimodal variation with peak rainy seasons occurring in late spring and fall. The roles of the annual march of sea surface temperature in the phase propagation and formation of various climatic regimes of tropical convection are also discussed. 34 refs., 8 figs., 1 tab.
Wang, Bin (Univ. of Hawaii, Honolulu, HI (United States))
Patterns of Convection in the Tropical Western Pacific
Patterns of Convection in the Tropical Western Pacific Patterns of Convection in the Tropical Western Pacific J. H. Mather Pacific Northwest National Laboratory Richland, Washington Introduction Convection is ubiquitous throughout the maritime continent region. However, the frequency of convec- tion is not uniform. While much of this region does not experience seasons to the same degree as one finds in mid-latitudes, the annual cycle of the sun's passage does have a large impact on convection throughout the maritime continent and the tropical western Pacific. The distribution of islands also affects convection in a variety of ways. Atmospheric Radiation Measurement (ARM) Program has three sites in the Tropical Western Pacific (TWP) region, illustrated in Figure 1. The sites are located on Manus, Nauru, and at Darwin, Australia.
The 30�60-Day Convection Seesaw between the Tropical Indian and Western Pacific Oceans
The tropical Indian and western Pacific oceans are two prominent action centers for tropical 30�60-day convective variability. When convection is enhanced over the equatorial Indian Ocean, the tropical western Pacific often experiences an ...
Baozhen Zhu; Bin Wang
The �Footprint� under a Decaying Tropical Mesoscale Convective System
On 10 February 1993, during the Tropical Ocean Global Atmosphere Coupled Ocean�Atmosphere Response Experiment, the two NOAA WP-3Ds and the NCAR Electra flew under the anvil region of a decaying mesoscale convective system (MCS). Satellite and ...
Mark F. Geldmeier; Gary M. Barnes
Tropical Convection and Precipitation Regimes in the Western United States
The authors have documented the relationship between tropical convection and precipitation regimes in the western United States. Circulation patterns associated with precipitation regimes are described and physical mechanisms are proposed. ...
Kingtse C. Mo; R. W. Higgins
Convective Storm Initiation in a Moist Tropical Environment
Radar and satellite data from the Tropical Rainfall Measuring Mission�Large-Scale Biosphere�Atmosphere (TRMM�LBA) project have been examined to determine causes for convective storm initiation in the southwest Amazon region. The locations and ...
Maria Andrea Lima; James W. Wilson
Climatology of Tropical Intraseasonal Convective Anomalies: 1979�2002
Tropical intraseasonal convective anomalies (TICA) have a central role in subseasonal changes in the coupled ocean�atmosphere system, but the climatology of TICA events has not been properly documented. This study exploits 24 years of outgoing ...
Charles Jones; Leila M. V. Carvalho; R. Wayne Higgins; Duane E. Waliser; J-K. E. Schemm
Transient Environmental Sensitivities of Explicitly Simulated Tropical Convection
A three-dimensional cloud-resolving model, maintained in a statistically steady convecting state by tropics-like forcing, is subjected to sudden (10 min) stimuli consisting of horizontally homogeneous temperature and/or moisture sources with ...
Stefan N. Tulich; Brian E. Mapes
Circulation Anomalies Associated with Tropical Convection during Northern Winter
Lagged cross correlations between outgoing longwave radiation (OLR) and National Meteorological Center global analyses are utilized to isolate the preferred upper-level and surface circulation anomalies associated with tropical convection during ...
George N. Kiladis; Klaus M. Weickmann
Electrically Active Convection in Tropical Easterly Waves and Implications for Tropical Cyclogenesis in the Atlantic and East Pacific
In this study, the authors investigated the characteristics of tropical easterly wave convection and the possible implications of convective structure on tropical cyclogenesis and intensification over the Atlantic Ocean and the east Pacific Ocean. ...
Kenneth D. Leppert II; Walter A. Petersen; Daniel J. Cecil
Sensitivity of Tropical Convection to Land Surface Processes
This paper studies the sensitivity of large-scale tropical convection to land surface changes in the general circulation model of the LMD. Ale method of analysis is based on a conceptual model of the energetics of convection applied every day of ...
J. Polcher
Response of Tropical Deep Convection to Localized Heating Perturbations: Implications for Aerosol-Induced Convective Invigoration
A cloud-system-resolving model is used to investigate the effects of localized heating/cooling perturbations on tropical deep convection, in the context of the aerosol �invigoration effect.� This effect supposes that a reduction of droplet ...
Hugh Morrison; Wojciech W. Grabowski
Aerosol Indirect Effects on Tropical Convection Characteristics under Conditions of Radiative�Convective Equilibrium
The impacts of enhanced aerosol concentrations such as those associated with dust intrusions on the trimodal distribution of tropical convection have been investigated through the use of large-domain (10 000 grid points), fine-resolution (1 km), ...
Susan C. van den Heever; Graeme L. Stephens; Norman B. Wood
Limiting Factors for Convective Cloud Top Height in the Tropics
Limiting Factors for Convective Cloud Top Limiting Factors for Convective Cloud Top Height in the Tropics M. P. Jensen and A. D. Del Genio National Aeronautics and Space Administration Goddard Institute for Space Studies Columbia University New York, New York Introduction Populations of tropical convective clouds are mainly comprised of three types: shallow trade cumulus, mid-level cumulus congestus and deep convective clouds (Johnson et al. 1999). Each of these cloud types has different impacts on the local radiation and water budgets. For climate model applications it is therefore important to understand the factors which determine the type of convective cloud that will occur. In this study, we concentrate on describing the factors that limit the cloud-top heights of mid-
A Radiative�Convective Equilibrium Perspective of Weakening of the Tropical Walker Circulation in Response to Global Warming
Both observational analysis and GCM simulations indicate that the tropical Walker circulation is becoming weaker and may continue to weaken as a consequence of climate change. Here, the authors use a conceptual radiative�convective equilibrium (...
Xianglei Huang; Hui-Wen Chuang; Andrew Dessler; Xiuhong Chen; Kenneth Minschwaner; Yi Ming; V. Ramaswamy
Sensitivity of Tropical Pacific Convection to Dry Layers at Mid- to Upper Levels: Simulation and Parameterization Tests
Numerical forecast experiments are carried out to investigate the implications of observed moisture variability in the tropical Pacific for deep convection. The study uses a series of quasi-cloud-resolving model forecasts with a triple-nested ...
James A. Ridout
The Role of Radiation in Influencing Tropical Cloud Distributions in a Radiative�Convective Equilibrium Cloud-Resolving Model
Observations by Johnson et al. depict regions of active tropical convection as possessing increased relative humidity through a deep layer and reduced low-level static stability when compared to nonconvecting regions. Shallow cumulus clouds, ...
Lyle Pakula; Graeme L. Stephens
Multiscale Convective Wave Disturbances in the Tropics: Insights from a Two-Dimensional Cloud-Resolving Model
Multiscale convective wave disturbances with structures broadly resembling observed tropical waves are found to emerge spontaneously in a nonrotating, two-dimensional cloud model forced by uniform cooling. To articulate the dynamics of these ...
Tropical Pacific impacts of convective momentum ... - Springer
MJO and monsoons, either directly by changing the atmospheric response to convection, or indirectly by altering the background climatology and ENSO. In fact
Association of Tropical Cirrus in the 10�15-km Layer with Deep Convective Sources: An Observational Study Combining Millimeter Radar Data and Satellite-Derived Trajectories
In this paper, millimeter cloud radar (MMCR) and Geosynchronous Meteorological Satellite (GMS) data are combined to study the properties of tropical cirrus that are common in the 10�15-km layer of the tropical troposphere in the western Pacific. ...
Gerald G. Mace; Min Deng; Brian Soden; Ed Zipser
2�3-Day Convective Variability in the Tropical Western Pacific
This paper is an examination of 2�3-day convective variability in the tropical Pacific region. The initial focus of the paper is on the western tropical Pacific during the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response ...
Carol Anne Clayson; Brian Strahl; Jon Schrage
Do the Tallest Convective Cells over the Tropical Ocean Have Slow Updrafts?
Far from continents, a few storms lift precipitation-size ice particles into the stratosphere, 17 to 18 km above the tropical ocean. This study is the first to examine the observed properties of a large sample of these extremely tall convective ...
Owen A. Kelley; John Stout; Michael Summers; Edward J. Zipser
ENSO impact on Kelvin waves and associated tropical convection
The impact of El Ni�o-Southern Oscillation (ENSO) on atmospheric Kelvin waves and associated tropical convection is investigated using the ECMWF Re-Analysis, NOAA OLR and the analysis technique introduced in a previous study. It is found that the ...
Gui-Ying Yang; Brian Hoskins
Simulated Relationships between Sea Surface Temperatures and Tropical Convection in Climate Models and Their Implications for Tropical Cyclone Activity
The impact of enhanced atmospheric CO2 concentrations on tropical convection and sea surface temperatures (SSTs) over the global tropics is assessed using five fully coupled atmospheric�oceanic general circulation models (AOGCMs). Relationships ...
Jenni L. Evans; Jeffrey J. Waters
Observations of a Convectively Coupled Kelvin Wave in the Eastern Pacific ITCZ
A case study of a convectively coupled Kelvin wave in the eastern Pacific intertropical convergence zone (ITCZ) is presented, as observed during the 1997 Pan American Climate Studies (PACS) Tropical Eastern Pacific Process Study (TEPPS). The ...
Katherine H. Straub; George N. Kiladis
Title: Radar-observed convective characteristics during TWP-ICE
Title: Radar-observed convective characteristics during TWP-ICE Title: Radar-observed convective characteristics during TWP-ICE Schumacher, Courtney Texas A&M University Houze, Robert University of Washington May, Peter Bureau or Meteorology Research Centre Frederick, Kaycee Cetrone, Jasmine Vallgren, Andreas Category: Field Campaigns This poster will describe the radar dataset obtained in the Tropical Warm Pool International Cloud Experiment (TWP-ICE), which is to take place 20 January - 14 February 2006 in the vicinity of Darwin, Australia. We will describe the convective systems observed during the project by two scanning C-band Doppler radars, one of which will provide dual-polarization measurements, and ARM's vertically pointing cloud radar and lidar installations. In addition, we will discuss the potential for combining
Environment and the Lifetime of Tropical Deep Convection in a Cloud-Permitting Regional Model Simulation
By applying a cloud tracking algorithm to tropical convective systems in a simulated a regional high resolution model simulation, this study documents the environmental conditions before and after convective systems are initiated over ocean and ...
Samson Hagos; Zhe Feng; Sally McFarlane; L. Ruby Leung
From Hot Towers to TRMM: Joanne Simpson and Advances in Tropical Convection Research
Joanne Simpson began contributing to advances in tropical convection about half a century ago. The hot tower hypothesis jointly put forth by Joanne Simpson and Herbert Riehl postulated that deep convective clouds populating the �equatorial trough ...
Robert A. Houze Jr.
Updraft and Downdraft Statistics of Simulated Tropical and Midlatitude Cumulus Convection
This paper presents a detailed analysis of updraft and downdraft statistics of simulated tropical oceanic and midlatitude continental cumulus convection, with an emphasis on the individual terms in the vertical momentum budget. Strong convective ...
Kuan-Man Xu; David A. Randall
A Systemic Analysis of Multiscale Deep Convective Variability over the Tropical Pacific
The multiscale tropical deep convective variability over the Pacific Ocean is examined with the 4-month high-resolution deep convection index (ITBB) derived from satellite imagery. With a systemic view, the complex phenomenon is described with ...
Wen-wen Tung; Mitchell W. Moncrieff; Jian-Bo Gao
A Satellite Infrared Technique to Estimate Tropical Convective and Stratiform Rainfall
This paper describes a new method of estimating both tropical convective precipitation and stratiform precipitation (produced under the anvils of mature and decaying convective systems) from satellite infrared data. The method, denoted CST (...
Robert F. Adler; Andrew J. Negri
Using the Stochastic Multicloud Model to Improve Tropical Convective Parameterization: A Paradigm Example
Despite recent advances in supercomputing, current general circulation models (GCMs) poorly represent the variability associated with organized tropical convection. A stochastic multicloud convective parameterization based on three cloud types (...
Yevgeniy Frenkel; Andrew J. Majda; Boualem Khouider
By applying a cloud-tracking algorithm to tropical convective systems in a regional high-resolution model simulation, this study documents the environmental conditions before and after convective systems are initiated over ocean and land by ...
The Relationship between Tropical Cyclone Intensity Change and the Strength of Inner-Core Convection
Convective intensity proxies measured by the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI), Precipitation Radar (PR), and Visible and Infrared Scanner (VIRS) are used to assess the relationship between intense convection in the ...
Haiyan Jiang
Walker-Type Mean Circulations and Convectively Coupled Tropical Waves as an Interacting System
Interactions between convectively coupled tropical waves and Walker-type mean circulations are examined using a two-dimensional analytic model wherein drying and cooling of the boundary layer by convective and mesoscale downdrafts are in ...
Jun-Ichi Yano; Mitchell W. Moncrieff; Wojciech W. Grabowski
Horizontal Structure and Seasonality of Large-Scale Circulations Associated with Submonthly Tropical Convection
The relationship between deep tropical convection and large-scale atmospheric circulation in the 6�30-day period range is examined. Regression relationships between filtered outgoing longwave radiation at various locations in the Tropics and 200- ...
A Modeling Study on the Early Electrical Development of Tropical Convection: Continental and Oceanic (Monsoon) Storms
Numerical modeling studies of continental tropical and maritime tropical convection were conducted using the two-dimensional, nonhydrostatic, cloud electrification model developed at the South Dakota School of Mines and Technology. The model ...
Scot C. Randell; Steven A. Rutledge; Richard D. Farley; John H. Helsdon Jr.
On the Observed Near Cancellation between Longwave and Shortwave Cloud Forcing in Tropical Regions
Observations based on Earth Radiation Budget Experiment (ERBE) satellite data indicate that there is a near cancellation between tropical longwave and shortwave cloud forcing in regions of deep convective activity. Cloud forcing depends on both ...
J. T. Kiehl
Properties of Tropical Cloud Ensembles Estimated Using a Cloud Model and an Observed Updraft Population
A simple cloud model is developed which is designed for both diagnostic studies and mesoscale cumulus parameterization experiments. The cloud model is combined with an observed population of tropical convective updrafts and used to examine the ...
William M. Frank; Charles Cohen
Estimation of Convective Rainfall from Lightning Observations
The objective of this study is to develop a technique to use lightning observations for estimating convective rainfall. A framework for rainfall estimation is developed in which key elements are 1) the rainfall�lightning ratio, that is, the ...
Alberto Tapia; James A. Smith; Michael Dixon
Interannual to Diurnal Variations in Tropical and Subtropical Deep Convective Clouds and Convective Overshooting from Seven Years of AMSU-B Measurements
This study surveys interannual to diurnal variations of tropical deep convective clouds and convective overshooting using the Advanced Microwave Sounding Unit B (AMSU-B) aboard the NOAA polar orbiting satellites from 1999 to 2005. The methodology ...
Gang Hong; Georg Heygster; Justus Notholt; Stefan A. Buehler
Tropical Cyclone Convection and Intensity Analysis Using Differenced Infrared and Water Vapor Imagery
A technique to identify and quantify intense convection in tropical cyclones (TCs) using bispectral, geostationary satellite imagery is explored. This technique involves differencing the water vapor (WV) and infrared window (IRW) channel ...
Timothy L. Olander; Christopher S. Velden
The effect of moist convection on the tropospheric response to tropical and subtropical zonally asymmetric torques
Tropospheric winds can be altered by vertical transfers of momentum due to orographic gravity waves and convection. Previous work showed that, in dry models, such zonally asymmetric torques produce a pattern of tropical ascent that is well-...
William R. Boos; Tiffany A. Shaw
Impact of Stochastic Convection on Ensemble Forecasts of Tropical Cyclone Development
Two versions of the Navy Operational Global Atmospheric Prediction System (NOGAPS) global ensemble, with and without a stochastic convection scheme, are compared regarding their performance in predicting the development and evolution of tropical ...
Andrew Snyder; Zhaoxia Pu; Carolyn A. Reynolds
Structural Characteristics of Deep Convective Systems over Tropical Africa and the Atlantic Ocean
The structural properties of convective cloud clusters of tropical Africa and the Atlantic Ocean are studied using six summers of Meteosat satellite data in the atmospheric infrared window. A cluster at a given brightness temperature threshold is ...
L. A. Toledo Machado; M. Desbois; J-Ph Duvel
Microphysics of Maritime Tropical Convective Updrafts at Temperatures from ?20� to ?60�
Anvils produced by vigorous tropical convection contribute significantly to the earth�s radiation balance, and their radiative properties depend largely on the concentrations and sizes of the ice particles that form them. These microphysical ...
Andrew J. Heymsfield; Aaron Bansemer; Gerald Heymsfield; Alexandre O. Fierro
Numerical Simulation of a Tropical Mesoscale Convective System Using the Arakawa-Schubert Cumulus Parameterization
As an extension of the work presented in an accompanying paper of Kao and Ogura, the Arakawa-Schubert cumulus parameterization scheme is examined prognostically in a modeling study of the evolution of a convectively driven tropical mesoscale ...
Yoshi Ogura; Chih-Yue Jim Kao
Intraseasonal Modulation of the North Pacific Storm Track by Tropical Convection in Boreal Winter
The modulation of the North Pacific storm track by tropical convection on intraseasonal time scales (30�90 days) in boreal winter (December�March) is investigated using the NCEP�NCAR reanalysis and NOAA satellite outgoing longwave radiation (OLR) ...
Yi Deng; Tianyu Jiang
On the Potential of VHF Wind Profilers for Studying Convective Processes in the Tropics
In this paper we provide a set of examples to demonstrate the potential of VHF radar wind profilers for studying tropical convection processes. Our examples were extracted from data obtained from the NOAA/CU Pacific Profiler Network, which has ...
B. B. Balsley; D. A. Carter; A. C. Riddle; W. L. Ecklund; K. S. Gage
Microphysical Processes Evident in Aerosol Forcing of Tropical Deep Convective Clouds
This study investigates the effects of aerosols on tropical deep convective clouds (DCCs). A series of large-scale, two-dimensional cloud-resolving model simulations was completed, differing only in the concentration of aerosols available to act ...
Rachel L. Storer; Susan C. van den Heever
A Satellite Study of Tropical Moist Convection and Environmental Variability: A Moisture and Thermal Budget Analysis
The thermodynamic variability associated with moist convection over tropical oceans is analyzed by making use of a variety of satellite sensors including radars, an infrared and microwave sounder unit, and microwave radiometer and scatterometer ...
Hirohiko Masunaga
The Interaction Between Deep Convection and Easterly Waves over Tropical North Africa: A Weather State Perspective
The interaction between deep convection and easterly waves over tropical North Africa is studied using a weather state (WS) dataset from the International Cloud Climatology Project (ISCCP) and reanalysis products from the European Centre for ...
Ademe Mekonnen; William B. Rossow
Climatic Equilibrium of the Atmospheric Convective Boundary Layer over a Tropical Ocean
A one-dimensional thermodynamic model for a partially mixed, partly cloudy, convective boundary layer (CBL) is coupled to a radiation model to compute equilibrium solutions for a tropical CBL and troposphere in energy balance over the ocean. For ...
Alan K. Betts; W. Ridgway
Latent Heating and Mixing Due to Entrainment in Tropical Deep Convection
Recent studies have noted the role of latent heating above the freezing level in reconciling Riehl and Malkus� Hot Tower Hypothesis (HTH) with evidence of diluted tropical deep convective cores. This study evaluates recent modifications to the HTH ...
Clayton J. McGee; Susan C. van den Heever
Influence of Sea Surface Temperature on Humidity and Temperature in the Outflow of Tropical Deep Convection
Multiple years of measurements of tropical upper-tropospheric temperature and humidity by the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) project are analyzed in the vicinity of deep convective outflow to study the ...
Zhengzhao Johnny Luo; Dieter Kley; Richard H. Johnson; G. Y. Liu; Susanne Nawrath; Herman G. J. Smit
On the Identification of the Large-Scale Properties of Tropical Convection using Cloud Regimes
The use of cloud regimes in identifying tropical convection and the associated large-scale atmospheric properties is investigated. The regimes are derived by applying cluster analysis to satellite retrievals of daytime-averaged frequency ...
Jackson Tan; Christian Jakob; Todd P. Lane
Reproducibility by Climate Models of Cloud Radiative Forcing Associated with Tropical Convection
In this study, cloud radiative forcing (CRF) associated with convective activity over tropical oceans is analyzed for monthly mean data from twentieth-century simulations of 18 climate models participating in phase 3 of the Coupled Model ...
Hiroki Ichikawa; Hirohiko Masunaga; Yoko Tsushima; Hiroshi Kanzawa
Organization of Tropical Convection in Low Vertical Wind Shears: The Role of Water Vapor
A modeling study is conducted to gain insight into the factors that control the intensity and organization of tropical convection, and in particular to examine if organization occurs in the absence of factors such as vertical wind shear or ...
The thermodynamic variability associated with moist convection over tropical oceans is analyzed by making use of a variety of satellite sensors including radars, an infrared and microwave sounder unit, and a microwave radiometer and scatterometer ...
Tropical Cyclogenesis Sensitivity to Environmental Parameters in Radiative-Convective Equilibrium
In this study, the relationship between the likelihood of tropical cyclogenesis and external environmental forcings is explored in the simplest idealized modelling framework possible: radiative-convective equilibrium on a ...
Nolan, David S.
Feature-Point Detection Using Distance Transforms: Application to Tracking Tropical Convective Complexes
The identification, tracking, and statistical analysis of tropical convective complexes using satellite imagery is explored in the context of identifying feature points suitable for tracking. The feature points are determined based on the shape ...
K. I. Hodges
The Skill of ECMWF Medium-Range Forecasts during the Year of Tropical Convection 2008
This study uses the European Centre for Medium-Range Weather Forecasts (ECMWF) model-generated high-resolution 10-day-long predictions for the Year of Tropical Convection (YOTC) 2008. Precipitation forecast skills of the model over the tropics ...
Arindam Chakraborty
Mesoscale Convective Vortices Observed during BAMEX. Part II: Influences on Secondary Deep Convection
Observations from the Bow Echo and Mesoscale Convective Vortex (MCV) Experiment are used to examine the role of the five mesoscale convective vortices described in Part I on heavy precipitation during the daytime heating cycle. Persistent ...
Stanley B. Trier; Christopher A. Davis
Convective Influence on the Heat Balance of the Tropical Tropopause Layer: A Cloud-Resolving Model Study
The tropical tropopause layer (TTL), and in particular the cold point tropopause, has been previously suggested as a feature decoupled from convection. Using a cloud-resolving model, the authors demonstrate that convection, in fact, has a cooling ...
Zhiming Kuang; Christopher S. Bretherton
Convective and Rainfall Properties of Tropical Cyclone Inner Cores and Rainbands from 11 Years of TRMM Data
Convective and rainfall properties of tropical cyclones (TCs) are statistically quantified by using Tropical Rainfall Measuring Mission (TRMM) data from December 1997 to December 2008. A semimanual method is used to divide the TC raining area into ...
Haiyan Jiang; Ellen M. Ramirez; Daniel J. Cecil
Thermodynamic Properties of Mesoscale Convective Systems Observed during BAMEX
Dropsonde observations from the Bow Echo and Mesoscale Convective Vortex Experiment (BAMEX) are used to document the spatiotemporal variability of temperature, moisture, and wind within mesoscale convective systems (MCSs). Onion-type sounding ...
James Correia Jr.; Raymond W. Arritt
Thermodynamic and Circulation Characteristics, of Winter Monsoon Tropical Mesoscale Convection
During the December 1978 field phase of the International Winter Monsoon Experiment (Winter MONEX), a regular diurnal cycle of deep convective activity occurred over the South China Sea immediately to the north of Borneo. The convection was ...
Richad H. Johnson; Donald C. Kriete
Simulation of Tropical Convective Systems. Part I: A Cumulus Parameterization
A new cumulus parametefization is developed for ffse in mesoscale model simulations of precipitating convective systems. It is designed to estimate convective properties using a cloud model that interacts with the mesoscale model in a physically ...
Distribution of Tropical Tropospheric Water Vapor
Utilizing a conceptual model for tropical convection and observational data for water vapor, the maintenance of the vertical distribution of the tropical tropospheric water vapor is discussed. While deep convection induces large-scale subsidence ...
De-Zheng Sun; Richard S. Lindzen
The Association of Tall Eyewall Convection with Tropical Cyclone Intensification .
??Despite decades of research, operational weather agencies still find it difficult to predict change in the intensity of a tropical cyclone's surface wind. This dissertation� (more)
Kelley, Owen A.
Tropical Island Convection in the Absence of Significant Topography. Part I: Life Cycle of Diurnally Forced Convection
Diurnally forced convection was observed over the Tiwi Islands, north of the Australian continent, as part of the Maritime Continent Thunderstorm Experiment. Immature peninsula-scale (5�15 km) sea breezes were observed to initiate moist ...
R. E. Carbone; J. W. Wilson; T. D. Keenan; J. M. Hacker
Characteristics of Vertical Velocity Cores in Different Convective Systems Observed over Gadanki, India
The Indian mesosphere�stratosphere�troposphere (MST) radar measurements during the passage of 60 convective systems are used to study the vertical air velocity (w) characteristics of tropical convection. The up- and downdraft cores and various ...
K. N. Uma; T. Narayana Rao
Links between Tropical Convection and Variations of the Extratropical Circulation during TOGA COARE
Data from the Intensive Observation Period of the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (November 1992�February 1993) have been used to investigate the links between intraseasonal variations in tropical ...
Greg C. Tyrrell; David J. Karoly; John L. McBride
The Relationship between Satellite Measured Convective Bursts and Tropical Cyclone Intensification
The relationship between the mean temperature of the top of the cloud canopies and the future maximum winds of Atlantic Ocean tropical cyclones is analyzed. The area-average cloud top temperatures from 309 observations of 12 tropical cyclones ...
Joseph Steranka; Edward B. Rodgers; R. Cecil Gentry
Effects of Downdrafts and Mesoscale Convective Organization on the Heat and Moisture Budgets of Tropical Cloud Clusters. Part III: Effects of Mesoscale Convective Organization
The effects of mesoscale convective organization on the large-scale heat and moisture budgets of tropical cloud clusters are studied using the GATE Phase III data. Two basic questions concerning the mesoscale effects are addressed: 1) the ...
Ming-Dean Cheng; Michio Yanai
Structure of Large-Scale Convective Anomalies over Tropical Oceans
Geographical variations in the variance and cross-correlation of monthly mean sea surface temperature (SST), outgoing longwave radiation (OLR, a proxy for deep convection and vertical motion), and convergence of winds at the surface and at 850 mb ...
David S. Gutzler; Tamara M. Wood
Numerical Modeling of Gravity Wave Generation by Deep Tropical Convection
Although convective clouds are known to generate internal gravity waves, the mechanisms responsible are not well understood. The present study seeks to clarify the dynamics of wave generation using a high-resolution numerical model of deep ...
Todd P. Lane; Michael J. Reeder; Terry L. Clark
Stratospheric Gravity Waves Generated by Multiscale Tropical Convection
The generation of gravity waves by multiscale cloud systems evolving in an initially motionless and thermodynamically uniform environment is explored using a two-dimensional cloud-system-resolving model. The simulated convection has similar depth ...
Todd P. Lane; Mitchell W. Moncrieff
The Transition to Strong Convection
Recent work has shown that observations of tropical precipitation conform to properties associated with critical phenomena in other systems. Here some of these universal properties are used to probe the physics of tropical convection empirically, ...
J. David Neelin; Ole Peters; Katrina Hales
A Trajectory Analysis of Tropical Upper-Tropospheric Moisture and Convection
It is shown that the distribution of upper-tropospheric humidity (UTH) in the cloud-free Tropics can be simulated with a simple model in which air expelled from moist convective regions is dried by subsidence along its trajectory. The ...
Eric P. Salath� Jr.; Dennis L. Hartmann
Thermodynamic Environments of Deep Convection in Atlantic Tropical Disturbances
Conditional composites of dropsondes deployed into eight tropical Atlantic weather systems during 2010 are analyzed. The samples are conditioned based on cloud-top temperature within 10 km of the dropsonde, the radius from the cyclonic circulation ...
Christopher A. Davis; David A. Ahijevych
Tropical Intraseasonal Oscillation, Super Cloud Clusters, and Cumulus Convection Schemes
A new framework for interpreting the origin of the tropical intraseasonal oscillation (TISO), which avoids the speed and scale selection problems in the previous theories, is proposed in this study. In this interpretation TISO is viewed as an ...
Winston C. Chao; Shian-Jiann Lin
Coupling between Gravity Waves and Tropical Convection at Mesoscales
An idealized cloud-system-resolving model simulation is used to examine the coupling between a tropical cloud population and the mesoscale gravity waves that it generates. Spectral analyses of the cloud and gravity wave fields identify a clear ...
Todd P. Lane; Fuqing Zhang
Observations and Modeling of Banded Orographic Convection
Radar images and numerical simulations of three shallow convective precipitation events over the Coastal Range in western Oregon are presented. In one of these events, unusually well-defined quasi-stationary banded formations produced large ...
Daniel J. Kirshbaum; Dale R. Durran
TRMM Radar Observations of Shallow Precipitation over the Tropical Oceans
Observations from the precipitation radar aboard the Tropical Rainfall Measuring Mission satellite provide the first opportunity to map vertical structure properties of rain over the entire Tropics and subtropics. Storm height histograms reveal a ...
David A. Short; Kenji Nakamura
Modeling the Impact of Convective Entrainment on the Tropical Tropopause
Simulations with the Weather Research and Forecasting (WRF) cloud-resolving model of deep moist convective events reveal net cooling near the tropopause (15�18 km above ground), caused by a combination of large-scale ascent and small-scale ...
F. J. Robinson; S. C. Sherwood
A Test of Convective Parameterizations in a Tropical Cyclone Model
In recent years a number of different methods have been proposed for the inclusion of the effects of cumuli in numerical models of tropical cyclones. In this paper several of the Kuo-type parameterizations have been tested by simulating the ...
Jay S. Hobgood; John N. Rayner
Virtual Field Campaigns on Deep Tropical Convection in Climate Models
High-resolution time�height data over warm tropical oceans are examined, from three global atmosphere models [GFDL�s Atmosphere Model 2 (AM2), NCAR�s Community Atmosphere Model, version 3 (CAM3), and a NASA Global Modeling and Assimilation Office ...
Brian Mapes; Julio Bacmeister; Marat Khairoutdinov; Cecile Hannay; Ming Zhao
Relationships between tropical cyclone intensity and satellite based indicators of inner core convection: 85 GHz ice scattering signature and lightning
A key component in the maintenance and intensification of tropical cyclones is the transverse circulation, which transports mass and momentum and provides latent heat release via inner core convective updrafts. This study examines these updrafts indirectly, using satellite-borne observations of the scattering of upwelling microwave radiation by precipitation sized ice and satellite-borne observations of lightning. The observations are then compared to tropical cyclone intensity and the resulting relationships are assessed. The size of ice particles is tied to updraft strength, in that stronger updrafts produce more supercooled liquid water, leading to larger graupel through riming. Large graupel and a high supercooled liquid water content are necessary ingredients for charge separation, leading to lightning. Various parameters derived from the inner core ice scattering signature are computed for regions encircling hurricanes and typhoons, and observations of lightning activity or inactivity are analyzed. As expected, increasing ice scattering signature is found to correspond to increasing tropical cyclone intensity. However, the highest correlations do not involve indicators of convective intensity, as they were expected to. Instead, the highest correlations with tropical cyclone intensity result from the ice scattering signature parameters most closely associated with the areal extent of at least moderate precipitation rates. Correlations tend to be of the same sign for both present cyclone intensity at the time of the satellite overpass and subsequent intensity change. Correlations are higher for future cyclone intensity than for either of these. These correlations are much higher for the Atlantic and the Eastern North Pacific than for the Western North Pacific. It is hypothesized that processes involved with the most intense or rapidly intensifying tropical cyclones (more commonly found in the Western North Pacific) are responsible for these differences. The lightning observations are more limited than the microwave observations, because the short amount of time in which lightning can be detected may not adequately represent a particular storms electrical activity. These observations reveal no clear relationships between electrical activity and tropical cyclone intensity. In the examination of case studies, the paradoxical situation of much greater lightning activity in rainbands than in eyewalls is noted.
Cecil, Daniel Joseph
Interaction between Intraseasonal Oscillations of the Midlatitude Flow and Tropical Convection during 1979 Northern Summer: The Pacific Ocean
It has been inferred and illustrated by many studies in terms of outgoing longwave radiation (OLR) and velocity potential (?) that energy is input into the intraseasonal oscillation through tropical cumulus convection, especially over the monsoon ...
Tsing-Chang Chen; Ming-Chen Yen
Influence of Convective Momentum Transport on Mixed Rossby-Gravity waves: A contribution to tropical two-day waves
Influences of convective momentum transport (CMT) on tropical waves are analytically studied with an idealized model, which captures the first-order baroclinic structure in the vertical. The CMT has significant influence on the mixed Rossby-...
Lei Zhou; In-Sik Kang
The Relationship between Precipitation and Lightning in Tropical Island Convection: A C-Band Polarimetric Radar Study
One of the primary scientific objectives of the Maritime Continent Thunderstorm Experiment was to study cloud electrification processes in tropical island convection, in particular, the coupling between ice phase precipitation and lightning ...
Lawrence D. Carey; Steven A. Rutledge
Quantitative Assessment of Diurnal Variation of Tropical Convection Simulated by a Global Nonhydrostatic Model without Cumulus Parameterization
This study investigated the resolution dependence of diurnal variation in tropical convective systems represented by a global nonhydrostatic model without cumulus parameterization. This paper describes the detailed characteristics of diurnal ...
Akira T. Noda; Kazuyoshi Oouchi; Masaki Satoh; Hirofumi Tomita
The Role of Large-Scale Atmospheric Circulation in the Relationship between Tropical Convection and Sea Surface Temperature
In this paper, the authors study the influence of the large-scale atmospheric circulation on the relationship between sea surface temperature (SST) and tropical convection inferred from outgoing longwave radiation (OLR). They find that under ...
K-M. Lau; H-T. Wu; S. Bony
The effects of imposed stratospheric cooling on the maximum intensity of tropical cyclones in axisymmetric radiative-convective equilibrium
The effects of stratospheric cooling and sea surface temperature (SST) warming on tropical cyclone (TC) potential intensity (PI) are explored using an axisymmetric cloud-resolving model run to radiative-convective equilibrium (RCE). Almost all ...
Hamish A. Ramsay
Convection over Tropical Africa and the Atlantic Ocean during Northern Summer. Part I: Interannual and Diurnal Variations
Some aspects of the interannual and the diurnal variations of the convection over the tropical Africa and the Atlantic Ocean are derived using Meteosat data. The study is based on four summer months (June, July, August and September) of three ...
Jean Philippe Duvel
Squall Lines and Convectively Coupled Gravity Waves in the Tropics: Why Do Most Cloud Systems Propagate Westward?
The coupling between tropical convection and zonally propagating gravity waves is assessed through Fourier analysis of high-resolution (3-hourly, 0.5�) satellite rainfall data. Results show the familiar enhancement in power along the dispersion ...
Stefan N. Tulich; George N. Kiladis
Modulation of South Indian Ocean Tropical Cyclones by the Madden�Julian Oscillation and Convectively Coupled Equatorial Waves
The subseasonal modulation of tropical cyclone (TC) genesis by large-scale atmospheric wave modes is studied using data from the south Indian Ocean region. The modes considered are the Madden�Julian oscillation (MJO), and the convectively coupled ...
Miloud Bessafi; Matthew C. Wheeler
The sensitivity of tropical convective precipitation to the direct radiative forcings of black carbon aerosols emitted from major regions
Previous works have suggested that the direct radiative forcing (DRF) of black carbon (BC) aerosols are able to force a significant change in tropical convective precipitation ranging from the Pacific and Indian Ocean to ...
Wang, Chien
Spatial and Annual Variations in the Diurnal Cycle of Large-Scale Tropical Convective Cloudiness and Precipitation
Three years of three-hourly infrared satellite data from the American geostationary satellites were used to determine the large-scale spatial and temporal variations in the diurnal cycle of tropical convective precipitation. The region examined ...
Bernard N. Meisner; Phillip A. Arkin
Comparison of the Highly Reflective Cloud and Outgoing Longwave Radiation Datasets for Use in Estimating Tropical Deep Convection
Currently, there are two long-term satellite-derived datasets most are frequently used as indices for tropical deep convection. These are the Outgoing Longwave Radiation (OLR) and Highly Reflective Cloud (HRC) datasets. Although both of these ...
Duane E. Waliser; Nicholas E. Graham; Catherine Gautier
Lidar Observations of Banded Convection during BLX83
Lidar observations of clear-air convection during the 1983 Boundary Layer Experiment (BLX83) reveal the presence of elongated, parallel regions of updrafts marked by enhanced aerosol backscattering. These linear (banded) aerosol structures were ...
R. A. Ferrare; J. L. Schols; E. W. Eloranta; R. Coulter
Observations of Vertical Wind Shear Heterogeneity in Convective Boundary Layers
Dual-Doppler wind syntheses from mobile radar observations obtained during the International H2O Project document some of the spatial variability of vertical wind profiles in convective boundary layers. Much of the variability of popular ...
Paul Markowski; Yvette Richardson
Observations from Space and Thermal Convection: A Historical Perspective
An abbreviated historical account of the evolution of the satellite meteorology program is presented. Emphasis is placed on the importance of the satellite and its space platform for observing and studying atmospheric convection. Particular ...
Ernest M. Agee
Airborne Doppler Lidar Observations of Convective Phenomena in Oklahoma
On 30 June 1981, the wind fields around a variety of convective clouds, ranging from large thunderstorm complexes to isolated cumulus congestus, were observed in Oklahoma using an airborne Doppler lidar operated by the National Aeronautics and ...
Eugene W. McCaul Jr.; Howard B. Bluestein; Richard J. Doviak
Comparing Model-produced Convective Cloudiness with Observations
Convective cloudiness generated by a cumulus parameterization scheme of a large-scale numerical weather prediction model was compared with analyses of clouds observed by geosynchronous satellites. The comparisons were performed over an equatorial ...
D. C. Norquist; C. Yang
Tropical Wave Instabilities: Convective Interaction with Dynamics Using the Emanuel Convective Parameterization
Wave-CISK and evaporation-wind feedback modes, also known as WISHE (wind-induced surface heat exchange) modes, are investigated using a two-dimensional (x?p), hydrostatic, nonrotational model linearized about a basic state in radiative-convective ...
Randy G. Brown; Christopher S. Bretherton
Tropical anvil cirrus evolution from observations and numerical...
cirrus evolution from observations and numerical simulations Deng, Min University of Utah Mace, Gerald University of Utah Category: Modeling The tropical anvil cirrus formation...
Evidence from Tropical Raindrop Spectra of the Origin of Rain from Stratiform versus Convective Clouds
An analysis of temporal variations in gamma parameters of raindrop spectra is presented utilizing surface-based observations from the Tropical Ocean Global Atmosphere Couple Ocean-Atmosphere Experiment. An observed dramatic change in the N0 ...
Ali Tokay; David A. Short
Effects of Downdrafts and Mesoscale Convective Organization on the Heat and Moisture Budgets of Tropical Cloud Clusters. Part I: A Diagnostic Cumulus Ensemble Model
A diagnostic cumulus ensemble model is developed to study the effects of convective-scale downdrafts and mesoscale convective organization on the heat and moisture budgets of tropical cloud clusters. The model adopts the spectral representation ...
Ming-Dean Cheng
The Role of Cloud Microphysics Parameterization in the Simulation of Mesoscale Convective System Clouds and Precipitation in the Tropical Western Pacific
This paper presents a detailed analysis of convection-permitting cloud simulations, aimed at increasing the understanding of the role of parameterized cloud microphysics in the simulation of mesoscale convective systems (MCSs) in the tropical ...
K. Van Weverberg; A. M. Vogelmann; W. Lin; E. P. Luke; A. Cialella; P. Minnis; M. Khaiyer; E. R. Boer; M. P. Jensen
Convectively Coupled Kelvin Waves over Tropical Africa during the Boreal Summer: Structure and Variability
The structure and variability of convectively coupled Kelvin waves during the boreal summer are explored using satellite-observed brightness temperature data and ECMWF reanalyses. Kelvin wave activity is most prominent between the central and ...
Ademe Mekonnen; Chris D. Thorncroft; Anantha R. Aiyyer; George N. Kiladis
A Three-Dimensional Simulation of a Tropical Squall Line: Convective Organization and Thermodynamic Vertical Transport
Three-dimensional convective-scale simulations of an African squall line, observed during the French COPT 81 experiment, are presented. Three simulations with different representations of large-scale forcing are performed on a domain of 50 km (...
Jean-Luc Redelsperger; Jean-Philippe Lafore
Statistical Assessment of Tropical Convection-Permitting Model Simulations Using a Cell-Tracking Algorithm
This study presents a method for comparing convection-permitting model simulations to radar observations using an innovative object-based approach. The method uses the automated cell-tracking algorithm, Thunderstorm Identification Tracking ...
Simon Caine; Todd P. Lane; Peter T. May; Christian Jakob; Steven T. Siems; Michael J. Manton; James Pinto
Development of Convective Systems over Baja California during Tropical Cyclone Linda (2003)
Characteristics of the life cycle and motion of convective systems that occurred over the Baja California Peninsula were determined from a case study in September of 2003. This note applies data from satellite imagery, regular observations from ...
Luis M. Farf�n
Lagrangian Diagnostics of Tropical Deep Convection and Its Effect upon Upper-Tropospheric Humidity
This study combines geostationary water vapor imagery with optical cloud property retrievals and microwave sea surface observations in order to investigate, in a Lagrangian framework, (i) the importance of cirrus anvil sublimation on tropical ...
�kos Horv�th; Brian J. Soden
Satellite Microwave Surface Observations in Tropical Cyclones
Sea surface estimates of local winds, waves, and rain-rate conditions are crucial to complement infrared/visible satellite images in estimating the strength of tropical cyclones (TCs). Satellite measurements at microwave frequencies are thus key ...
Yves Quilfen; Bertrand Chapron; Jean Tournadre
An Observational Analysis of Tropical Cyclone Recurvature
Data for 21 years (1957�77) of North Pacific rawinsondes were examined to investigate the interaction between the synoptic-scale circulation and tropical cyclones prior to, and during, the recurvature process. This study is believed to be the ...
Stephen Hodanish; William M. Gray
Effects of Downdrafts and Mesoscale Convective Organization on the Heat and Moisture Budgets of Tropical Cloud Clusters. Part II: Effects of Convective-Scale Downdrafts
The diagnostic cumulus ensemble model presented in Part I of this paper is applied to the data taken during Phase III of the GARP Tropical Atlantic Experiment (GATE) to examine the effects of convective-scale downdrafts on the large-scale heat ...
Tropical Cyclone Motion. A Comparison of Theory and Observation
The analytic predictions of tropical cyclone motion by Holland are shown to be in very good agreement with observations in the Australian southwest Pacific region. These results indicate that a combined linear asymmetric advection and divergence ...
Greg J. Holland
A Comparison of Adaptive Observing Guidance for Atlantic Tropical Cyclones
Airborne adaptive observations have been collected for more than two decades in the neighborhood of tropical cyclones, to attempt to improve short-range forecasts of cyclone track. However, only simple subjective strategies for adaptive ...
S. J. Majumdar; S. D. Aberson; C. H. Bishop; R. Buizza; M. S. Peng; C. A. Reynolds
Interpretation of Adaptive Observing Guidance for Atlantic Tropical Cyclones
Adaptive observing guidance products for Atlantic tropical cyclones are compared using composite techniques that allow one to quantitatively examine differences in the spatial structures of the guidance maps and relate these differences to the ...
C. A. Reynolds; M. S. Peng; S. J. Majumdar; S. D. Aberson; C. H. Bishop; R. Buizza
Dendritic Patterns in Tropical Cumulus: An Observational Analysis
An observational analysis of the structure and synoptic setting of tropical dendritic cumulus formations was undertaken using 30 months of global data from the Moderate Resolution Imaging Spectroradiometer aboard the National Aeronautics and ...
Stephen D. Nicholls; George S. Young
Environmental Conditions Prior to Formation of a Midget Tropical Cyclone during TCM-93
During a 10-day period in the Tropical Cyclone Motion (TCM-93) field experiment over the tropical western North Pacific, tropical cyclone formation occurred in association with persistent deep convection that was observed over low-level, north-...
Patrick A. Harr; Michael S. Kalafsky; Russell L. Elsberry
A Tropical "NAT-like" belt observed from space
The optical properties of cold tropical tropopause clouds are examined on a global scale, using two years of space-borne lidar observations from CALIPSO (June 2006 ? May 2008). The linear depolarization ratio, color ratio and backscatter signal are analyzed in tropical clouds colder than 200 K in a way similar to recent studies of Polar Stratospheric Clouds (PSCs). It is found that the three categories of particles encountered in PSC (Ice, Sulfate Ternary Solutions or STS, and Nitric Acid Trihydrate or NAT) do also occur in tropical cold cloud layers. Particles with optical properties similar to NAT are few, but they cover the tropical belt and represent about 20% of cold cloud tropical particles. The optical behavior of these particles requires them to be small, non-spherical, optically thin, and persistent in the TTL at temperatures colder than 200 K; NAT particles and very small ice crystals meet these criteria.
Chepfer, H�l�ne; 10.1029/2008GL036289
Resonant Response of Deep Convection to Surface Hot Spots
Observations show substantial variations of the intensity of tropical and/or summertime deep convection on land that are not explained by standard measures of convective instability. One feature that distinguishes land surfaces is their ...
F. J. Robinson; S. C. Sherwood; Y. Li
Changes in the Interaction between Tropical Convection, Radiation, and the Large-Scale Circulation in a Warming Environment
This paper explores the response of the tropical hydrologic cycle to surface warming through the lens of large-domain cloud-system-resolving model experiments run in a radiative�convective equilibrium framework. Simulations are run for 55 days and ...
Derek J. Posselt; Susan van den Heever; Graeme Stephens; Matthew R. Igel
Characteristics of Rain Integral Parameters during Tropical Convective, Transition, and Stratiform Rain at Gadanki and Its Application in Rain Retrieval
In the present study the characteristics of rain integral parameters during tropical convective (C), transition (T), and stratiform (S) types of rain are studied with the help of Joss�Waldvogel disdrometer (JWD), L-band, and very-high-frequency ...
Sanjay Sharma; Mahen Konwar; Diganta Kumar Sarma; M. C. R. Kalapureddy; A. R. Jain
The Vertical Structure of Tropical Convection and Its Impact on the Budgets of Water Vapor and Ozone
Convective clouds in the Tropics that penetrate the boundary layer inversion preferentially detrain into a shallow outflow layer (2�5 km) or a deep outflow layer (10�17 km). The properties of these layers are diagnosed from a one-dimensional ...
Ian Folkins; Randall V. Martin
Latitudinal Variations of the Convective Source and Propagation Condition of Inertio-Gravity Waves in the Tropics
Latitudinal variations of the convective source and vertical propagation condition of inertio-gravity waves (IGWs) in the tropical region (30�S�30�N) are examined using high-resolution Global Cloud Imagery (GCI) and 6-hourly NCEP�NCAR reanalysis ...
Hye-Yeong Chun; Jung-Suk Goh; In-Sun Song; Lucrezia Ricciardulli
Rapid Scan Views of Convectively Generated Mesovortices in Sheared Tropical Cyclone Gustav (2002)
On 9�10 September 2002, multiple mesovortices were captured in great detail by rapid scan visible satellite imagery in subtropical, then later, Tropical Storm Gustav. These mesovortices were observed as low-level cloud swirls while the low-level ...
Eric A. Hendricks; Michael T. Montgomery
Observations and Numerical Simulation of Atmospheric Cellular Convection over Mesoscale Topography
Radar and satellite images provide observations of convective rolls and other structures in the convective boundary layer (CBL), but the data are intermittent, and neither radar nor satellite gives a complete picture of roll circulation in the ...
Wenshou Tian; Douglas J. Parker; Charles A. D. Kilburn
Intense Convection Observed by NASA ER-2 in Hurricane Emily (2005)
On 17 July, intense convection in the eyewall of Hurricane Emily (2005) was observed by the high-altitude (20 km) NASA ER-2 aircraft. Analysis of this convection is undertaken using downward-looking radar, passive microwave radiometer, electric ...
Daniel J. Cecil; Kevin R. Quinlan; Douglas M. Mach
Observations of Convection Initiation �Failure� from the 12 June 2002 IHOP Deployment
Observations of the development of cumulus convection, which reached depths of several kilometers but failed to develop into sustained, precipitating, cumulonimbus clouds�an event the authors term �convection initiation failure��are presented ...
Paul Markowski; Christina Hannon; Erik Rasmussen
Diurnal Cycle of Shallow and Deep Convection for a Tropical Land and an Ocean Environment and Its Relationship to Synoptic Wind Regimes
The characteristics of shallow and deep convection during the Tropical Rainfall Measuring Mission/Large-Scale Biosphere�Atmosphere Experiment in Amazonia (TRMM/LBA) and the Eastern Pacific Investigation of Climate Processes in the Coupled Ocean�...
L. Gustavo Pereira; Steven A. Rutledge
Relationships between Tropical Cyclone Intensity and Satellite-Based Indicators of Inner Core Convection: 85-GHz Ice-Scattering Signature and Lightning
A key component in the maintenance and intensification of tropical cyclones is the transverse circulation, which transports mass and momentum and provides latent heat release via inner core convective updrafts. This study examines these updrafts ...
Daniel J. Cecil; Edward J. Zipser
A Numerical Study of Three-Dimensional Gravity Waves Triggered by Deep Tropical Convection and Their Role in the Dynamics of the QBO
A 3D mesoscale model is used to study the structure of convectively triggered gravity waves in the Tropics and their role in the dynamics of the middle atmosphere. Simulations with three stratospheric background zonal wind cases are examined. In ...
C. Piani; D. Durran; M. J. Alexander; J. R. Holton
Evaluation of Hydrometeor Phase and Ice Properties in Cloud-Resolving Model Simulations of Tropical Deep Convection Using Radiance and Polarization Measurements
Satellite measurements are used to evaluate the glaciation, particle shape, and effective radius in cloud-resolving model simulations of tropical deep convection. Multidirectional polarized reflectances constrain the ice crystal geometry and the ...
Bastiaan van Diedenhoven; Ann M. Fridlind; Andrew S. Ackerman; Brian Cairns
United Mechanisms for the Generation of Low- and High-Frequency Tropical Waves. Part I: Control Experiments with Moist Convective Adjustment
To examine several mechanisms for the generation of low- and high-frequency tropical waves, numerical experiments are conducted using an idealized nine-level R21 spectral model with the original scheme of moist convective adjustment (MCA). The ...
Y. Hayashi; D. G. Golder
High-Resolution Simulation of Mean Convection and Its Intraseasonal Variability over the Tropics in the MRI/JMA 20-km Mesh AGCM
Tropical mean convection and its organization on different spatiotemporal scales in a simulation using the Meteorological Research Institute/Japan Meteorological Agency (MRI/JMA) global atmospheric general circulation model (AGCM) at 20-km ...
K. Rajendran; A. Kitoh; R. Mizuta; S. Sajani; T. Nakazawa
Multiscale Convective Overturning in Mesoscale Convective Systems: Reconciling Observations, Simulations, and Theory
An analysis of how parameterized convection interacts with hydrostatic, explicitly resolved precipitation processes to represent multiscale convective overturning in a mesoscale-resolution numerical simulation is presented. Critically important ...
John S. Kain; J. Michael Fritsch
A tropical � NAT-like � belt observed from space
The optical properties of cold tropical tropopause clouds are examined on a global scale, using two years of space-borne lidar observations from CALIPSO (June 2006- May 2008). The linear depolarization ratio, color ratio and backscatter signal are analyzed in tropical clouds colder than 200 K in a way similar to recent studies of Polar Stratospheric Clouds (PSCs). It is found that the three categories of particles encountered in PSC (Ice, Sulfate Ternary Solutions or STS, and Nitric Acid Trihydrate or NAT) do also occur in tropical cold cloud layers. Particles with optical properties similar to NAT are few, but they cover the hal-00439695, version 1- 8 Dec 2009 tropical belt and represent about 20 % of cold cloud tropical particles all year long. The optical behavior of these particles requires them to be very small, non-spherical, optically thin, and persistent in the TTL at temperatures colder than 200 K; NAT particles and very small ice crystals meet these criteria and are right now the best candidates to explain the presented observations. 2
unknown authors
Comparing the Convective Structure and Microphysics in Two Sahelian Mesoscale Convective Systems: Radar Observations and CRM Simulations
Two mesoscale convective systems (MCSs) observed during the African Monsoon Multidisciplinary Analyses (AMMA) experiment are simulated using the three-dimensional (3D) Goddard Cumulus Ensemble model. This study was undertaken to determine the ...
Nick Guy; Xiping Zeng; Steven A. Rutledge; Wei-Kuo Tao
A Tropical Squall Line Observed during the COPT 81 Experiment in West Africa. Part 1: Kinematic Structure Inferred from Dual-Doppler Radar Data
This paper deals with the analysis of a tropical squall line, observed on 22 June 1981 during the COPT 81 (Convection Profonde Tropicale) experiment. The present Part I is restricted to the study of the kinematic structure of the system, which ...
Michel Chong; Paul Amayenc; Georges Scialom; Jacques Testud
A Satellite Observational and Numerical Study of Precipitation Characteristics in Western North Atlantic Tropical Cyclones
Special Sensor Microwave/Imager (SSM/I) observations were used to examine the spatial and temporal changes of the precipitation characteristics of tropical cyclones. SSM/I observations were also combined with the results of a tropical cyclone ...
Edward B. Rodgers; Simon W. Chang; Harold F. Pierce
Observed Antarctic Interannual Climate Variability and Tropical Linkages
This study reviews the mechanisms associated with Antarctic�tropical climate linkages and presents new analyses of the seasonality and spatial patterns of tropical climate signals in the Antarctic for the late 1950s to the present. Tropical ...
David P. Schneider; Yuko Okumura; Clara Deser
Long-Term Observations of Tropical Instability Waves
Reynolds sea surface temperature (SST) data showing tropical instability waves (TIWs) in the tropical Pacific are analyzed along with current measurements from the Tropical Atmosphere�Ocean (TAO) buoy array and wind speeds from the European ...
Robert F. Contreras
Observations of the Overland Reintensification of Tropical Storm Erin (2007)
Atlantic Tropical Depression Five (2007) briefly strengthened into Tropical Storm Erin over the western Gulf of Mexico shortly before making landfall as a tropical depression near Corpus Christi, Texas, on the morning of 16 August 2007. During ...
Derek S. Arndt; Jeffrey B. Basara; Renee A. McPherson; Bradley G. Illston; Gary D. McManus; David B. Demko
Radar Analysis of a Tropical Convective Boundary Layer with Shallow Cumulus Clouds
A situation of fair weather cloudy convection is examined using a dual Doppler radar, environmental measurements and cloud photogrammetry. The convective layer is characterized by the interaction between the northward monsoon wind at low levels ...
Laurence Eymard
Total lightning observations of severe convection over North Texas
Five severe convective cells over North Texas from three separate dates were examined to determine what three dimensional, or �total� lightning data can add to the understanding of a convective cell�s intensity, propagation, and severe weather potential. Total lightning data were obtained from Vaisala Inc.�s Dallas/Fort Worth (D/FW) Lightning Detection and Ranging (LDAR) network. Radar data from two Weather Surveillance Radar � 1988 Doppler (WSR-88D) sites were used for position data and information regarding the intensity and kinematic properties of each cell. Total lightning products used by the National Weather Service Forecast Office in Fort Worth, Texas were compared to total lightning flash rate; a quantity that has been shown to be correlated to changes in cell intensity inferred from other sources, such as radar and satellite data. These products, specifically flash extent density (FED) were also compared to CG flash rate and radar derived measures from the WSR-88D sites. The results of this work show that FED and total flash rate are well correlated, with an average Pearson correlation value of 0.73, indicating that previous total flash rate results may also apply to FED. Lightning hooks, holes, and notches in FED displays indicated likely updraft regions, while appendages were observed to develop prior to deviant motion with two supercells. These results, combined with a greater update frequency provided a useful complement to radar data in the warning decision process. FED jumps were observed prior to several severe weather reports, indicating that total lightning activity may be related to updraft strength as found in past studies. However, FED jumps were sometimes observed without any associated severe event. More work is clearly needed to define what FED changes are of most importance in the short-term prediction of storm severity. The usefulness of the total lightning data on these dates was dependant upon LDAR network status and distance of the cell from the network center. The results of this study suggest that combining total flash rate trends with visual displays of FED provides the greatest added benefit to forecasters in maintaining situational awareness during warning operations.
McKinney, Christopher Michael
Wavelet Analysis of Simulated Tropical Convective Cloud Systems. Part I: Basic Analysis
A wavelet analysis of a three-dimensional 7-day explicit simulation of the tropical cloud systems in the Global Atmosphere Research Programme (GARP) Atlantic Tropical Experiment Phase III is performed. Three physically distinct regimes (squall ...
Jun-Ichi Yano; Mitchell W. Moncrieff; Xiaoqing Wu; Michio Yamada
The Effects of Vertical Wind Shear on the Distribution of Convection in Tropical Cyclones
The influence of vertical wind shear on the azimuthal distribution of cloud-to-ground lightning in tropical cyclones was examined using flash locations from the National Lightning Detection Network. The study covers 35 Atlantic basin tropical ...
Kristen L. Corbosiero; John Molinari
A Composite Life Cycle of Nonsquall Mesoscale Convective Systems over the Tropical Ocean. Part I: Kinematic Fields
The wind fields associated with cloud clusters observed during the Global Atmospheric Research Program's Atlantic Tropical Experiment (GATE) are investigated. A compositing procedure is devised to isolate the cluster circulations. Satellite-...
Edward I. Tollerud; Steven K. Esbensen
A Composite Life Cycle of Nonsquall Mesoscale Convective Systems over the Tropical Ocean. Part II: Heat and Moisture Budgets
The heat and moisture budgets associated with five large nonsquall cloud clusters observed during Phase 3 of the Global Atmospheric Research Program's Atlantic Tropical Experiment (GATE) are investigated. The input data for the budget ...
Steven K. Esbensen; Jough-Tai Wang; Edward I. Tollerud
Regional Observations during the Landfall of Tropical Cyclone Juliette (2001) in Baja California, Mexico
This paper presents an observational analysis of tropical cyclone landfall over the eastern Pacific Ocean. The tropical cyclone that developed during the 2001 season off the Mexican coast was named Juliette and made landfall in the Baja ...
Projection of Tropical Cyclones on Wavenumber�Frequency-Filtered Equatorial Waves
The impact of localized convection associated with tropical cyclones (TCs) on activity ascribed to equatorial waves is estimated. An algorithm is used to remove outgoing longwave radiation (OLR) signal in the vicinity of observed tropical cyclones,...
Anantha Aiyyer; Ademe Mekonnen; Carl J. Schreck III
Observational Analysis of the Predictability of Mesoscale Convective Systems
Mesoscale convective systems (MCSs) have a large influence on the weather over the central United States during the warm season by generating essential rainfall and severe weather. To gain insight into the predictability of these systems, the ...
Israel L. Jirak; William R. Cotton
An Observational Analysis of a Developing Mesoscale Convective Complex
Dual-Doppler radar, surface mesonet, satellite, and upper-air sounding data from the 1985 Preliminary Regional Experiment for STORM-Central field experiment are used to analyze the early growth stages of a mesoscale convective complex (MCC) that ...
Jason E. Nachamkin; Ray L. McAnelly; William R. Cotton
Synoptic Mapping of Convective Structure from Undersampled Satellite Observations
Climate properties regulated by convection, such as water vapor, cloud cover, and related distributions, are undersampled in asynoptic data from an individual orbiting platform, which must therefore be restricted to time-mean distributions. A ...
Murry Salby; Fabrizio Sassi
Equatorial Wave Activity Derived from Fluctuations in Observed Convection
The spectrum of equatorial wave activity propagating vertically into the stratosphere is calculated from high-resolution imagery of the global convective pattern. Synoptic Global Cloud Imagery (GCI), constructed from six satellites simultaneously ...
John W. Bergman; Murry L. Salby
An Observational Study of Derecho-Producing Convective Systems
This study identifies the common large-scale environments associated with the development of derecho- producing convective systems (DCSs) from a large number of events. Patterns are identified using statistical clustering of the 500-mb ...
Michael C. Coniglio; David J. Stensrud; Michael B. Richman
Four-Dimensional Variational Data Assimilation of Heterogeneous Mesoscale Observations for a Strong Convective Case
On 19 September 1996, a squall line stretching from Nebraska to Texas with intense embedded convection moved eastward across the Kansas�Oklahoma area, where special observations were taken as part of a Water Vapor Intensive Observing Period ...
Y-R. Guo; Y-H. Kuo; J. Dudhia; D. Parsons; C. Rocken
Improving Convection Parameterization Using ARM Observations and NCAR Community Atmosphere Model
Highlight of Accomplishments: We made significant contribution to the ASR program in this funding cycle by better representing convective processes in GCMs based on knowledge gained from analysis of ARM/ASR observations. In addition, our work led to a much improved understanding of the interaction among aerosol, convection, clouds and climate in GCMs.
Zhang, Guang J [Scripps Institution of Oceanography
Numerical Simulation of Episodes of Organized Convection in Tropical Northern Africa
A large-domain convection-permitting numerical model is used to simulate episodes of deep convection, which are generated during the day over the Ethiopian Highlands and then propagate westward over the eastern and central Sahel region (5��20�N) ...
Arlene G. Laing; Stanley B. Trier; Christopher A. Davis
Observational Analysis of Tropical Cyclone Formation Associated with Monsoon Gyres
Large-scale monsoon gyres and the involved tropical cyclone formation over the western North Pacific have been documented in previous studies. The aim of this study is to understand how monsoon gyres affect tropical cyclone formation. An ...
Liguang Wu; Huijun Zong; Jia Liang
Aircraft Observations of Convective Systems in the Indian Ocean [EVS Event]
Aircraft Observations of Convective Systems in the Indian Ocean Aircraft Observations of Convective Systems in the Indian Ocean August 23, 2013 Speaker: Bradley Nicholas Guy National Research Council Postdoctoral Fellow NOAA National Severe Storms Laboratory Date: Friday, August 23, 2013 Time: 11:00 a.m. Location: Argonne National Laboratory TCS Building 240 Room 4301 In the DYNAMO (Dynamics of the Madden-Julian Oscillation) field experiment, a large number of measurement platforms were deployed to study environmental and convective cloud system characteristics of the Madden-Julian Oscillation (MJO) initiation region in the Indian Ocean. A mobile platform, the NOAA P-3 instrumented aircraft, sampled intense convective cloud systems, along with the surrounding environment. This presentation will explore the characteristics of mesoscale convective
Retrieval of Cloud Water and Water Vapor Contents from Doppler Radar Data in a Tropical Squall Line
This paper describes the retrieval of cloud water and water vapor contents from Doppler radar data. The convective part of a tropical squall line (22 June 1981) observed during the COPT 81 (Convection Profonde Tropicale 1981) West African ...
Dani�le Hauser; Paul Amayenc
Numerical Study of an Observed Orogenic Mesoscale Convective System. Part 1: Simulated Genesis and Comparison with Observations
The interaction of topographically induced thermally and mechanically driven diurnal flow regimes in the lee of the Rockies is shown to lead to the growth of a mesoscale convective system (MCS). An organic MCS observed during the 1977 combined ...
Gregory J. Tripoli; William R. Cotton
An Observational and Numerical Study of a Sheared, Convective Boundary Layer. Part I: Phoenix II Observations, Statistical Description, and Visualization
Four-dimensional velocity fields derived from dual Doppler radar observations are the basis of a description and statistical analysis of a convective, sheared planetary boundary layer during an afternoon over the High Plains of eastern Colorado. ...
Jeanne M. Schneider; Douglas K. Lilly
The Pacific�South American Modes and Tropical Convection during the Southern Hemisphere Winter
Atmospheric circulation features and convection patterns associated with two leading low-frequency modes in the Southern Hemisphere (SH) are examined in multiyear global reanalyses produced by NCEP�NCAR and NASA�DAO. The two leading modes, ...
Kingtse C. Mo; R. Wayne Higgins
Sensitivity of Tropical Convection to Sea Surface Temperature in the Absence of Large-Scale Flow
The response of convection to changing sea surface temperature (SST) in the absence of large-scale flow is examined, using a three-dimensional cloud resolving model. The model includes a five-category bulk microphysical scheme representing snow, ...
Adrian M. Tompkins; George C. Craig
Indo-Pacific Sea Surface Temperature Perturbations Associated with Intraseasonal Oscillations of Tropical Convection
Since the ISV of the convection is an intermittent phenomenon, the local mode analysis (LMA) technique is used to detect only the ensemble of intraseasonal events that are well organized at large scale. The LMA technique is further developed in ...
Jean Philippe Duvel; J�r�me Vialard
Tropical Convection on 7�21-Day Timescales over the Western Pacific
Evidence is presented to demonstrate that the oscillations of convection on 7�21-day timescales are an important component of the intraseasonal variability over the region spanning the equatorial western Pacific to the subtropical South Pacific. ...
Jon M. Schrage; Dayton G. Vincent
Conserved Variable Analysis of the Convective Boundary Layer Thermodynamic Structure over the Tropical Oceans
An analysis of FGGE dropwindsonde data using conserved thermodynamic variables shows mixing line structures for the convective boundary layer over the equatorial Pacific. Deeper boundary layers show a double structure. Reversals of the gradients ...
Alan K. Betts; Bruce A. Albrecht
Mesoscale Convective Vortices Observed during BAMEX. Part I: Kinematic and Thermodynamic Structure
Five cases of mesoscale convective vortices (MCVs) are described from observations collected during the Bow Echo and MCV Experiment (BAMEX) over the central United States during the period from 20 May to 6 July 2003. In the present paper, the ...
Christopher A. Davis; Stanley B. Trier
A Mesoscale Vortex Couplet Observed in the Trailing Anvil of a Multicellular Convective Complex
Observations collected during the Oklahoma�Kansas PRE-STORM experiment are used to document the evolution and structure of a mesoscale vortex couplet that developed in the mesoscale convective system that occurred on 16�17 June 1985. The ...
Johannes Verlinde; William R. Cotton
A Subtropical Oceanic Mesoscale Convective Vortex Observed during SoWMEX/TiMREX
This study examines a subtropical oceanic mesoscale convective vortex (MCV) that occurred from 1800 UTC 4 June to 1200 UTC 6 June 2008 during intensive observing period (IOP) 6 of the Southwest Monsoon Experiment (SoWMEX) and the Terrain-...
Hsiao-Wei Lai; Christopher A. Davis; Ben Jong-Dao Jou
Multiple-Doppler Radar Observations of the Evolution of Vorticity Extrema in a Convective Boundary Layer
Overdetermined, dual-Doppler wind syntheses are used to document the evolution, structure, and dynamics of vertical vorticity extrema observed in a convective boundary layer during the 12 June 2002 International H2O Project (IHOP) mission. ...
Paul Markowski; Christina Hannon
The Identification and Verification of Hazardous Convective Cells over Oceans Using Visible and Infrared Satellite Observations
Three algorithms based on geostationary visible and infrared (IR) observations are used to identify convective cells that do (or may) present a hazard to aviation over the oceans. The performance of these algorithms in detecting potentially ...
Michael F. Donovan; Earle R. Williams; Cathy Kessinger; Gary Blackburn; Paul H. Herzegh; Richard L. Bankert; Steve Miller; Frederick R. Mosher
Radar Observations of the Diurnally Forced Offshore Convective Lines along the Southeastern Coast of Taiwan
This study documents offshore convective lines along the southeastern coast of Taiwan, a frequent but poorly understood mesoscale phenomenon that influences coastal weather during the Taiwan mei-yu season. Doppler radar and surface observations ...
Cheng-Ku Yu; Ben Jong-Dao Jou
Total Lightning Characteristics Relative to Radar and Satellite Observations of Oklahoma Mesoscale Convective Systems
The advent of regional very high frequency (VHF) Lightning Mapping Arrays (LMAs) makes it possible to begin analyzing trends in total lightning characteristics in ensembles of mesoscale convective systems (MCSs). Flash initiations observed by the ...
Jeffrey A. Makowski; Donald R. MacGorman; Michael I. Biggerstaff; William H. Beasley
Tropical Cumulus Convection and Upward-Propagating Waves in Middle-Atmospheric GCMs
It is recognized that the resolved tropical wave spectrum can vary considerably among general circulation models (GCMs) and that these differences can have an important impact on the simulated climate. A comprehensive comparison of low-latitude ...
T. Horinouchi; S. Pawson; K. Shibata; U. Langematz; E. Manzini; M. A. Giorgetta; F. Sassi; R. J. Wilson; K. Hamilton; J. de Grandpr�; A. A. Scaife
Improvements of an Ice-Phase Microphysics Parameterization for Use in Numerical Simulations of Tropical Convection
It is important to properly simulate the extent and ice water content of tropical anvil clouds in numerical models that explicitly include cloud formation because of the significant effects that these clouds have on the radiation budget. For this ...
Steven K. Krueger; Qiang Fu; K. N. Liou; Hung-Neng S. Chin
SCOUT-O3/ACTIVE: High-altitude Aircraft Measurements around Deep Tropical Convection
During November and December 2005, two consortia of mainly European groups conducted an aircraft campaign in Darwin, Australia, to measure the composition of the tropical upper-troposphere and tropopause regions, between 12 and 20 km, in order to ...
G. Vaughan; K. Bower; C. Schiller; A. R. MacKenzie; T. Peter; H. Schlager; N. R. P. Harris; P. T. May
Convective Coupling and Interannual and Intraseasonal Coupled Variabilities in the Tropics
Recent analyses point at close structural similarities and intimate dynamical connections among the members of a wide spectrum of variabilities in the global Tropics. This suggests that these oscillations with widely different timescales may have ...
P. Goswami; Rameshan K.
Rainfall Observation from Tropical Rainfall Measuring Mission (TRMM) Satellite
National Space Development Agency of Japan (NASDA) successfully launched the Tropical Rainfall Measuring Mission (TRMM) observatory at 06:27 (JST) on Nov. 28, 1997. The TRMM satellite carries the first spaceborne Precipitation Radar (PR) which was developed ... Keywords: Clouds and the Earth's Radiant Energy System (CERES), El Ni�o, Lightning Imaging Sensor (LIS), Precipitation Radar (PR), TRMM Microwave Imager (TMI), Tropical Rainfall Measuring Mission (TRMM), Visible Infrared Scanner (VIRS), heavy rain, tropical cyclone
K. Hiroshima
The residual mean circulation in the tropical tropopause layer driven by tropical waves
We use latent heating estimates derived from rainfall observations to construct model experiments that isolate equatorial waves forced by tropical convection from mid-latitude synoptic-scale waves. These experiments are used to demonstrate that ...
David A. Ortland; M. Joan Alexander
The Onset of Convection in the Madden�Julian Oscillation
An observational study of the onset of convection in the Madden�Julian oscillation (MJO) was performed. Composites of radiosonde data from the Comprehensive Aerological Reference Data Set were constructed for an ensemble of tropical stations ...
Susan R. Kemball-Cook; Bryan C. Weare
Wavelet-Compressed Representation of Deep Moist Convection
The capacity of wavelets to effectively represent atmospheric processes under compression is tested by a dataset generated by a cloud-resolving model simulation of deep convective events observed during the Tropical Ocean Global Atmosphere ...
Jun-Ichi Yano; Peter Bechtold; Jean-Luc Redelsperger; Francoise Guichard
Observing Strategy and Observation Targeting for Tropical Cyclones Using Ensemble-Based Sensitivity Analysis and Data Assimilation
An ensemble Kalman filter data assimilation system for the Weather Research and Forecasting Model is used with ensemble-based sensitivity analysis to explore observing strategies and observation targeting for tropical cyclones. The case selected ...
Baoguo Xie; Fuqing Zhang; Qinghong Zhang; Jonathan Poterjoy; Yonghui Weng
The Tilt of the Leading Edge of Mesoscale Tropical Convective Lines
The tilt with height of the leading edge of seven mesoscale convective lines in GATE is determined by two independent methods. When averaged over time and along the line axis, the tilt is found to he surprisingly shallow, between 20 and 35 ...
M. A. LeMone; G. M. Barnes; E. J. Szoke; E. J. Zipser
Evidence of Tropical Forcing of the 6.5-Day Wave from Lightning Observations over Africa
A study employing observations and climatic reanalysis data is concerned with links between convection and the well-documented 6.5-day stratospheric global wave. Observations from a long-range lightning detection network, known as ZEUS, reveal an ...
Themis G. Chronis; Earle Williams; Emmanouil N. Anagnostou
Global Distribution of Tropical Deep Convection: Different Perspectives from TRMM Infrared and Radar Data
Cold cloud features (CCFs) are defined by grouping six full years of Tropical Rainfall Measuring Mission (TRMM) infrared pixels with brightness temperature at 10.8-?m wavelength (TB11) less than or equal to 210 and 235 K. Then the precipitation ...
Chuntao Liu; Edward J. Zipser; Stephen W. Nesbitt
How Do Atmosphere and Land Surface Influence Seasonal Changes of Convection in the Tropical Amazon?
Although the wet season in the tropical Amazon (10�N�20�S) at any one place and in any one year is initiated rapidly by synoptic systems, large-scale thermodynamic conditions modulate the frequency and intensity of these synoptic systems and ...
Rong Fu; Bin Zhu; Robert E. Dickinson
Observational Undersampling in Tropical Cyclones and Implications for Estimated Intensity
The maximum surface wind speed is an important parameter for tropical cyclone operational analysis and forecasting, since it defines the intensity of a cyclone. Operational forecast centers typically refer the wind speed to a maximum 1- or 10-min ...
Eric W. Uhlhorn; David S. Nolan
Tropical Cyclone Observation and Forecasting with and without Aircraft Reconnaissance
The contributions of aircraft reconnaissance to the accuracy of tropical cyclone center positioning, motion, and intensity determinations are examined, along with their impact on the accuracy of track and intensity forecasting. The analyses ...
Joel D. Martin; William M. Gray
Targeted Observations to Improve Operational Tropical Cyclone Track Forecast Guidance
Since 1997, the Tropical Prediction Center and the Hurricane Research Division have conducted operational synoptic surveillance missions with a Gulfstream IV-SP jet aircraft to improve numerical forecast guidance. Due to limited aircraft ...
Sim D. Aberson
Observed Interannual Variability of Tropical Troposphere Relative Humidity
Relative humidity fields from the High-Resolution Infrared Radiation Sounder (HIRS) flown on NOAA series satellites since 1979 have been used to study the seasonal aspects of the interannual variability of relative humidity in the tropical ...
Mark P. McCarthy; Ralf Toumi
Observational Analyses of North Atlantic Tropical Cyclones from NOAA Polar-Orbiting Satellite Microwave Data
Passive microwave observations from the current NOAA series of polar-orbiting satellites of a large sample of North Atlantic tropical cyclones are qualitatively and quantitatively analyzed. Microwave observations can penetrate the cloud cover ...
Christopher S. Velden
Assimilation of Synthetic Tropical Cyclone Observations into the Navy Operational Global Atmospheric Prediction System
In June 1990, the assimilation of synthetic tropical cyclone observations into the Navy Operational Global Atmospheric Prediction System (NOGAPS) was initiated at Fleet Numerical Oceanography Center (FNOC). These observations are derived directly ...
James S. Goerss; Richard A. Jeffries
Atlantic Tropical Cyclogenesis: A Three-Way Interaction between an African Easterly Wave, Diurnally Varying Convection, and a Convectively Coupled Atmospheric Kelvin Wave
This paper explores a three-way interaction between an African easterly wave (AEW), the diurnal cycle of convection over the Guinea Highlands (GHs), and a convectively coupled atmospheric equatorial Kelvin wave (CCKW). These interactions resulted ...
Michael J. Ventrice; Christopher D. Thorncroft; Matthew A. Janiga
Convective�Stratiform Precipitation Variability at Seasonal Scale from 8 Yr of TRMM Observations: Implications for Multiple Modes of Diurnal Variability
This study investigates the variability of convective and stratiform rainfall from 8 yr (1998�2005) of Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) and TRMM Microwave Imager (TMI) measurements, focusing on seasonal diurnal ...
Song Yang; Eric A. Smith
Comparison of Simulated and Observed Continental Tropical Anvil Clouds and Their Radiative Heating Profiles
Vertically pointing millimeter-wavelength radar observations of anvil clouds extending from mesoscale convective systems (MCSs) that pass over an Atmospheric Radiation Measurement Program (ARM) field site in Niamey, Niger, are compared to anvil ...
Scott W. Powell; Robert A. Houze Jr.; Anil Kumar; Sally A. McFarlane
The Boundary Layer of Tropical Cyclone Kerry (1979)
The boundary layer structure of Tropical Cyclone Kerry (1979) is investigated using composite analysis of research aircraft, surface ship, and automatic weather station observations. The boundary layer was moist, convective, and strongly ...
Peter G. Black; Greg J. Holland
Mantle Echoes Associated with Deep Convection: Observations and Numerical Simulations
Finescale radar observations of intense thermals/starting plumes, during the early stages of precipitation formation, were collected by an airborne Doppler radar on two separate days. The radar data were recorded as the aircraft flew underneath ...
Roger M. Wakimoto; Hanne V. Murphey; Robert G. Fovell; Wen-Chau Lee
Observations of Thermohaline Convection adjacent to Brunt Ice Shelf
Observations were made of ocean microstructure and horizontal currents adjacent to Brunt Ice Shelf in the southeastern Weddell Sea. Periods of in situ supercooled water extending as deep as 65 m were associated with ice nucleation and frazil ...
Ilker Fer; Keith Makinson; Keith W. Nicholls
Observational Analysis of Heavy Rainfall Mechanisms Associated with Severe Tropical Storm Bilis (2006) after Its Landfall
This observational study attempts to determine factors responsible for the distribution of precipitation over large areas of southern China induced by Bilis, a western North Pacific Ocean severe tropical storm that made landfall on the ...
Shuanzhu Gao; Zhiyong Meng; Fuqing Zhang; Lance F. Bosart
Observations of Record Cold Cloud-Top Temperatures in Tropical Cyclone Hilda (1990)
A detailed analysis is made of the development of a region of cold cloud-top temperatures in Tropical Cyclone Hilda (1990) in the Coral Sea off eastern Australia. Observed temperatures of approximately 173 K (?100�C) from two independent ...
Elizabeth E. Ebert; Greg J. Holland
Multichannel Microwave Radiometric Observations at Saipan during the 1990 Tropical Cyclone Motion Experiment
To estimate mesoscale variations in integrated water vapor, cloud liquid water, and temperature in a tropical region, multiwavelength microwave radiometric observations were carried out over a seven-week period on the island of Saipan during the ...
Yong Han; Dennis W. Thomson
Observation-Based Estimates of Surface Cooling Inhibition by Heavy Rainfall under Tropical Cyclones
Tropical cyclones drive intense ocean vertical mixing that explains most of the surface cooling observed in their wake (the �cold wake�). In this paper, the authors investigate the influence of cyclonic rainfall on the cold wake at a global scale ...
Nicolas C. Jourdain; Matthieu Lengaigne; J�rome Vialard; Gurvan Madec; Christophe E. Menkes; Emmanuel M. Vincent; Swen Jullien; Bernard Barnier
Systematic Variation of Observed Radar Reflectivity�Rainfall Rate Relations in the Tropics
The Tropical Rainfall Measuring Mission Global Validation Program provides a unique opportunity to compare radar datasets from different sites, because they are analyzed in a relatively uniform procedure. Monthly observed radar reflectivity�...
Eyal Amitai
Observed and Modeled Wind and Water-Level Response from Tropical Storm Marco (1990)
The Hurricane Research Division (HRD) analyzes surface wind fields in tropical storms and hurricanes using surface wind observations and aircraft flight-level wind measurements in the vicinity of the storms. The analyzed surface wind fields for ...
Sam H. Houston; Mark D. Powell
A Satellite Observational Study of Precipitation Characteristics in Western North Pacific Tropical Cyclones
Special Sensor Microwave/Imager (SSM/I) observations were used to examine spatial and temporal changes in the precipitation characteristics for western North Pacific tropical cyclones that reached storm stage or greater during 1987-92. The second ...
Edward B. Rodgers; Harold F. Pierce
Observational Evidence for Predictions of Tropical Cyclone Propagation Relative to Environmental Steering
Theories of vortex motion due to the variations of the Coriolis parameter and environmental vorticity are compared to observations of tropical cyclone motion relative to computed �steering flows� using previously published composite data. The ...
L. E. Carr III; Russell L. Elsberry
Intercomparison of Targeted Observation Guidance for Tropical Cyclones in the Northwestern Pacific
This study compares six different guidance products for targeted observations over the northwest Pacific Ocean for 84 cases of 2-day forecasts in 2006 and highlights the unique dynamical features affecting the tropical cyclone (TC) tracks in this ...
Chun-Chieh Wu; Jan-Huey Chen; Sharanya J. Majumdar; Melinda S. Peng; Carolyn A. Reynolds; Sim D. Aberson; Roberto Buizza; Munehiko Yamaguchi; Shin-Gan Chen; Tetsuo Nakazawa; Kun-Hsuan Chou
Observational Evidence for Alternate Modes of Track-Altering Binary Tropical Cyclone Scenarios
An observational study of western North Pacific tropical cyclones (TC) revealed many cases of two TCs whose tracks were altered by processes that were quite different from the mutual advection (Fujiwhara-type) processes. Thus, four conceptual ...
Lester E. Carr III; Mark A. Boothe; Russell L. Elsberry
Comparing tropical precipitation simulated by the Met Office NWP and climate models with satellite observations
Forecasts of precipitation and water vapor made by the UK Met Office global Numerical Weather Prediction (NWP) model are evaluated using products from satellite observations of Special Sensor Microwave Imager/Sounder (SSMIS) and Tropical Rainfall ...
Chunlei Liu; Richard P. Allan; Malcolm Brooks; Sean Milton
Environmental Dynamical Control of Tropical Cyclone Intensity�An Observational Study
The effects of two environmental dynamical factors, namely, the transitional speed and vertical wind shear, on tropical cyclone (TC) intensification, intensity, and lifetime peak intensity were analyzed based on observations in the western North ...
Zhihua Zeng; Yuqing Wang; Chun-Chieh Wu
Tropopause Characteristics and Variability from 11 yr of SHADOZ Observations in the Southern Tropics and Subtropics
In this paper, tropopause characteristics observed from tropical to subtropical Southern Hemisphere stations using Southern Hemisphere Additional Ozonesonde (SHADOZ) data are presented for the 11-yr period of 1998�2008. Three different definitions ...
V. Sivakumar; H. Bencherif; N. B�gue; A. M. Thompson
Tropical Tropopause Transition Layer Cirrus as Represented by CALIPSO Lidar Observations
The spatial and temporal variability of cirrus cloud fraction within the tropical tropopause transition layer (TTL) is investigated based on three years of data from the Cloud�Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) ...
Katrina S. Virts; John M. Wallace; Qiang Fu; Thomas P. Ackerman
Doppler Profiler and Radar Observations of Boundary Layer Variability during the Landfall of Tropical Storm Gabrielle
Detailed observations of boundary layer structure were acquired on 14 September 2001, prior to and during the landfall of Tropical Storm Gabrielle. The Mobile Integrated Profiling System (MIPS) and the Shared Mobile Atmospheric Research and ...
Kevin R. Knupp; Justin Walters; Michael Biggerstaff
Cloud-to-Ground Lightning Observations from TOGA COARE: Selected Results and Lightning Location Algorithms
Recently, observations of electrified oceanic convection and associated cloud-to-ground (CG) lightning were obtained over the tropical western Pacific Ocean during TOGA COARE (Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response ...
Walter A. Petersen; Steven A. Rutledge; Richard E. Orville
An Observational Study of Tropical Cyclone Spin-Up in Supertyphoon Jangmi (2008) from 24�27 September
An observational study of tropical cyclone intensification is performed using dropsondes, in situ flight-level data, satellite imagery, and ELDORA radar during the spin-up of Tropical Storm Jangmi (2008) in the Western North Pacific. This event ...
Neil T. Sanger; Michael T. Montgomery; Roger K. Smith; Michael M. Bell
Comparison between Observed Convective Cloud-Base Heights and Lifting Condensation Level for Two Different Lifted Parcels
Approximately 400 Automated Surface Observing System (ASOS) observations of convective cloud-base heights at 2300 UTC were collected from April through August of 2001. These observations were compared with lifting condensation level (LCL) heights ...
Jeffrey P. Craven; Ryan E. Jewell; Harold E. Brooks
Maintenance of the Free-Tropospheric Tropical Water Vapor Distribution. Part I: Clear Regime Budget
The water vapor budget of the free troposphere of the maritime Tropics is investigated using radiosonde observations, analyzed fields, and satellite observations, with particular attention paid to regions free of organized convection. In these ...
Multiscale Convective Organization and the YOTC Virtual Global Field Campaign
The Year of Tropical Convection (YOTC) project recognizes that major improvements are needed in how the tropics are represented in climate models. Tropical convection is organized into multiscale precipitation systems with an underlying chaotic order. ...
Mitchell W. Moncrieff; Duane E. Waliser; Martin J. Miller; Melvyn A. Shapiro; Ghassem R. Asrar; James Caughey
COPT 81: A Field Experiment Designed for the Study of Dynamics and Electrical Activity of Deep Convection in Continental Tropical Regions
During May and June 1981 several French research organizations, the University of Abidjan (Ivory coast) and the Agency for security of Aeronautical Navigation (ASECNA), participated in the observational field program called �Convection Profonde ...
Gilles Sommeria; J. Testud
A Numerical Study of Stratospheric Gravity Waves Triggered by Squall Lines Observed during the TOGA COARE and COPT-81 Experiments
A 3D mesoscale model is used to study the structure and intensity of stratospheric gravity waves generated by tropical convection. Two prototypical cases are examined: a squall line observed during the Tropical Ocean Global Atmosphere Coupled ...
C. Piani; D. R. Durran
Small-Scale Motions Observed by Aircraft in the Tropical Lower Stratosphere: Evidence for Mixing and its Relationship to Large-Scale Flows
Measurments of temperature and ozone from instrumental aircraft in the tropical lower stratosphere show the presence of small-scale disturbances generated by 1) underlying cumulus convection and 2) Kelvin-Helmholtz instability. The disturbances ...
Leonhard Pfister; Walter Starr; Roger Craig; Max Loewenstein; Marion Legg
The Vertical Structure of TOGA COARE Convection. Part I: Radar Echo Distributions
Radar data collected by the 5-cm MIT radar, which was deployed aboard the R/V Vickers during the intensive observing period of the Tropical Ocean Global Atmosphere Coupled Ocean�Atmosphere Response Experiment, are partitioned into convective and ...
Charlotte A. DeMott; Steven A. Rutledge
Improving Simulations of Convective Systems from TRMM LBA: Easterly and Westerly Regimes
The 3D Goddard Cumulus Ensemble model is used to simulate two convective events observed during the Tropical Rainfall Measuring Mission Large-Scale Biosphere�Atmosphere (TRMM LBA) experiment in Brazil. These two events epitomized the type of ...
S. Lang; W-K. Tao; J. Simpson; R. Cifelli; S. Rutledge; W. Olson; J. Halverson
Diagnosis of Convective and Mesoscale Motions During Phase IH of Gate
Observational evidence from GATE suggests that a significant fraction of precipitation in tropical disturbances over the eastern Atlantic occurs beneath anvil-type mesoscale convective systems that are frequently associated with intense ...
Richard H. Johnson
Comparison of Ice-Phase Microphysical Parameterization Schemes Using Numerical Simulations of Tropical Convection
A numerical cloud model is used to evaluate the performance of several ice parameterizations. Results from simulations using these schemes are contrasted with each other, with an ice-free control simulation, and with observations to determine to ...
Michale McCumber; Wei-Kuo Tao; Joanne Simpson; Richard Penc; Su-Tzai Soong
Convective Modes for Significant Severe Thunderstorms in the Contiguous United States. Part III: Tropical Cyclone Tornadoes
A gridded, hourly, three-dimensional environmental mesoanalysis database at the Storm Prediction Center (SPC), based on objectively analyzed surface observations blended with the Rapid Update Cycle (RUC) model-analysis fields and described in ...
Roger Edwards; Andrew R. Dean; Richard L. Thompson; Bryan T. Smith
A Numerical Investigation of Several Factors Contributing to the Observed Variable Intensity of Deep Convection over South Florida
This study employs a revised version of the Colorado State University three-dimensional numerical cloud scale model to investigate the observed behavior of deep convection over South Florida on 17 July 1973. A brief description of recent model ...
Retrieval of Thermal and Microphysical Variables in Observed Convective Storms. Part 1: Model Development and Preliminary Testing
The air flow in convective storms, the force that regulate the flow, and the processes that produce hydrometeors of various kinds are all being studied intensively by meteorologists using Doppler radar observations. The research reported here ...
Conrad L. Ziegler
Electrification of Stratiform Regions in Mesoscale Convective Systems. Part I: An Observational Comparison of Symmetric and Asymmetric MCSs
The kinematic, microphysical, and electrical structures of two mesoscale convective systems (MCSs) observed during the 1991 Cooperative Oklahoma Profiler Studies (COPS91) experiment are analyzed. Profiles of the vertical electric field structure ...
Terry J. Schuur; Steven A. Rutledge
Assimilating Airborne Doppler Radar Observations with an Ensemble Kalman Filter for Convection-Permitting Hurricane Initialization and Prediction: Katrina (2005)
Through a Weather Research and Forecasting model (WRF)-based ensemble Kalman filter (EnKF) data assimilation system, the impact of assimilating airborne radar observations for the convection-permitting analysis and prediction of Hurricane Katrina (...
Yonghui Weng; Fuqing Zhang
Tropical-Extratropical Teleconnections during the Northern Hemisphere Winter. Part II: Relationships between Monthly Mean Northern Hemisphere Circulation Patterns and Proxies for Tropical Convection
Monthly mean teleconnections during the northern winter between proxies for tropical heating (OLR and SST data) and Northern Hemisphere 700 mb circulation patterns (PNA, TNH, and WPO) are examined, principally with correlation analysis. In ...
Robert E. Livezey; Kingtse C. Mo
MIMIC: A New Approach to Visualizing Satellite Microwave Imagery of Tropical Cyclones
Satellite-based passive microwave imagery of tropical cyclones (TCs) is an invaluable resource for assessing the organization and evolution of convective structures in TCs when often no other comparable observations exist. However, the current ...
Anthony J. Wimmers; Christopher S. Velden
A Numerical Study of Lapse-Rate Adjustments in the Tropical Atmosphere
Observations in the tropics have shown that the lapse rate of virtual Potential temperature ?v normally resembles that of a reversible moist adiabat. In the present study, a mesoscale numerical model with parameterized convection is used to ...
Charles Cohen; William M. Frank
Vorticity Budget for AMEX. Part II: Simulations of Monsoon Onset, Midtropospheric Lows, and Tropical Cyclone Behavior
Diagnostics from the observational dataset of the Australian Monsoon Experiment (AMEX) have revealed two interesting characteristics of convective systems over the Australian Tropics (Part I of this study). The first is a midlevel convergence ...
Noel E. Davidson
El Ni�o as a Natural Experiment for Studying the Tropical Tropopause Region
The interannual variability of the tropical tropopause region between 14 and 18 km is examined using observations of convection, winds, and tropopause temperatures from reanalyses and water vapor from satellites. This variability is compared to a ...
A. Gettelman; W. J. Randel; S. Massie; F. Wu; W. G. Read; J. M. Russell III
12.811 Tropical Meteorology, Spring 2005
This course describes the behavior and dynamics of the tropical troposphere, from the large-scale energy balance down to cumulus convection and tropical cyclones. Topics include: Radiative-convective equilibrium; the Hadley ...
Emanuel, Kerry
Observational Evidence for the Mutual Regulation of the Tropical Hydrological Cycle and Tropical Sea Surface Temperatures
From the analysis of surface, upper-air, and satellite observations it is suggested that the hydrological cycle associated with the Madden�Julian oscillation acts in the mode of a self-regulating oscillator. The regulation occurs as a feedback ...
Graeme L. Stephens; Peter J. Webster; Richard H. Johnson; Richard Engelen; Tristan L'Ecuyer
Remote Sensing Observations from MTI Satellites and GMS Over Tropical Island of Nauru
Remote Sensing Observations from MTI Satellites and Remote Sensing Observations from MTI Satellites and GMS Over Tropical Island of Nauru W. M. Porch, P. Chylek, and B. Henderson Los Alamos National Laboratory Los Alamos, New Mexico Introduction The observations of island cloud trails have revealed a strong relationship between the character and frequency of occurrence of island cloud trails and the Tropical Ocean Southern Oscillation (MacFarlane et al. 2004 a, b). Island cloud trails from the U.S. Department of Energy's (DOE) Atmospheric and Radiation Measurement (ARM) facility of Nauru persist for more than 50 km (Nordeen et al. 2001) and resemble ship trail clouds found in the Eastern Ocean Margins (Porch et al. 1999). Island trail clouds are much more frequently observed during La Niña periods than El Niño periods (Figure 1). This
Toward an understanding of vertical momentum transports in cloud system resolving model simulations of multiscale tropical convection
This study examines the characteristics of convective momentum transport (CMT) and gravity wave momentum transport (GWMT) in two-dimensional cloud-system resolving model simulations, including the relationships between the two transports. A linear ...
Tiffany A. Shaw; Todd P. Lane
Convective Entrainment and Large-Scale Organization of Tropical Precipitation: Sensitivity of the CNRM-CM5 Hierarchy of Models
The spurious double intertropical convergence zone (ITCZ) is a systematic bias affecting state-of-the-art coupled general circulation models (GCMs). Modeling studies show that the ITCZ structure is very sensitive to moist convection ...
Boutheina Oueslati; Gilles Bellon
Characteristics of 3�4- and 6�8-Day Period Disturbances Observed over the Tropical Indian Ocean
A field observational campaign [i.e., the Mirai Indian Ocean cruise for the Study of the MJO-convection Onset (MISMO)] was conducted over the central equatorial Indian Ocean in October�December 2006. During MISMO, large-scale organized convection ...
Kazuaki Yasunaga; Kunio Yoneyama; Qoosaku Moteki; Mikiko Fujita; Yukari N. Takayabu; Junko Suzuki; Tomoki Ushiyama; Brian Mapes
Aircraft Observation of Convection Waves over Southern Germany�A Case Study
A vertical cross section of 100 km � 10 km through a daytime midlatitude troposphere is analyzed using aircraft turbulence data with 1.5-m spatial resolution. Convectively forced internal gravity waves, also referred to as �convection waves,� ...
Thomas Hauf
Observational Evaluation of a Convective Quasi-Equilibrium View of Monsoons
Idealized dynamical theories that employ a convective quasi-equilibrium (QE) treatment for the diabatic effects of moist convection have been used to explain the location, intensity, and intraseasonal evolution of monsoons. This paper examines ...
Ji Nie; William R. Boos; Zhiming Kuang
Observations and Modeling of Shallow Convective Clouds: Implications for the Indirect Aerosol Effects
Observations Observations and Modeling of Shallow Convective Clouds: Implications for the Indirect Aerosol Effects Sylwester Arabas 1 , Joanna Slawinska 1 , Wojciech Grabowski 2 , Hugh Morrison 2 , Hanna Pawlowska 1 1 : Institute of Geophysics, University of Warsaw, Poland 2 : National Center for Atmospheric Research, Boulder, Colorado, USA 348 constants for reference state and lateral boundary conditions 349 ibcx=icyx 350 ibcy=icyy*j3 351 ibcz=icyz 352 irlx=irelx 353 irly=irely*j3 354 irdbc=0 355 fcr0=fcr0*icorio 356 itdl=0 357 tdt=40.*3600. 358 u0tdl=u00 359 360 361 constants for thermodynamics 362 c bv=sqrt(st*g) 363 bv=st 364 st=bv**2/g 365 cp=3.5*rg 366 cap=rg/cp 367 pr00=rg*rh00*tt00
Observational Evaluation of a Convective Quasi-Equilibrium View of Monsoons JI NIE, WILLIAM R. BOOS, AND ZHIMING KUANG
Observational Evaluation of a Convective Quasi-Equilibrium View of Monsoons JI NIE, WILLIAM R. BOOS been used to explain the location, intensity, and intraseasonal evolution of monsoons. This paper examines whether observations of the earth's regional monsoons are consistent with the assumption of QE
The Impact of Observational Technology on Climate Database Quality: Tropical Cyclones in the Tasman Sea
The recorded climatology of tropical cyclones that affect the Tasman Sea spans the period from 1911 to the present. This climatology is a subset of the much larger Australian Tropical Cyclone database, which is the official record of all tropical ...
Bruce W. Buckley; Lance M. Leslie; Milton S. Speer
Convective Contribution to the Genesis of Hurricane Ophelia (2005)
The convection occurring in the tropical depression that became Hurricane Ophelia (2005) was investigated just prior to tropical storm formation. Doppler radar showed a deep, wide, intense convective cell of a type that has been previously ...
Robert A. Houze Jr.; Wen-Chau Lee; Michael M. Bell
Mesoscale Convective Systems Defined by Their 85-GHz Ice Scattering Signature: Size and Intensity Comparison over Tropical Oceans and Continents
This study used the 85-GHz ice scattering signature to describe the size, intensity, and geographic distribution of mesoscale convective systems (MCSs) between 35�N and 35�S for January, April, July, and October 1993. An MCS was defined as an ...
Karen I. Mohr; Edward J. Zipser
On the Vertical Distribution of Mean Vertical Velocities in the Convective Regions during the Wet and Dry Spells of the Monsoon over Gadanki
The Indian Mesosphere�Stratosphere�Troposphere (MST) radar observations of vertical distribution of mean vertical velocities w in convective regions during the wet and dry spells of the Indian summer monsoon over a tropical station at Gadanki, ...
K. N. Uma; K. Kishore Kumar; Siddarth Shankar Das; T. N. Rao; T. M. Satyanarayana
Parameterization of Convective Effects on the Momentum and Vorticity Budgets of Synoptic-Scale Atlantic Tropical Waves
Dynamic budgets of an average synoptic-scale wave have been made by Stevens (1979) from GARP Atlantic Tropical Experiment Phase III B- and A/B-scale data composited by Thompson et al. (1979). In the present study the apparent sources of momentum ...
Lloyd J. Shapiro; Duane E. Stevens
Fitting Dynamic Models to the Geosat Sea Level Observations in the Tropical Pacific Ocean. Part I: A Free Wave Model
Free, equatorially trapped sinusoidal wave solutions to a linear model on an equatorial beta plane are used to fit the Geosat altimetric sea level observations in the Tropical Pacific Ocean. The Kalman filter technique is used to estimate the ...
Lee-Lueng Fu; Jorge Vazquez; Claire Perigaud
An Evaluation of Microphysics Fields from Mesoscale Model Simulations of Tropical Cyclones. Part I: Comparisons with Observations
This study presents a framework for comparing hydrometeor and vertical velocity fields from mesoscale model simulations of tropical cyclones with observations of these fields from a variety of platforms. The framework is based on the Yuter and ...
Robert F. Rogers; Michael L. Black; Shuyi S. Chen; Robert A. Black
Observations and Forecasts from the Landfall of Tropical Cyclones John, Lane, and Paul (2006) over Northwestern Mexico
This study focuses on track and intensity changes of three tropical cyclones that, during the season of 2006, developed in the eastern North Pacific basin and made landfall over northwestern Mexico. Observational datasets, including satellite and ...
Luis M. Farf�n; Rosario Romero-Centeno; G. B. Raga
Surface Flux Observations on the Southeastern Tropical Pacific Ocean and Attribution of SST Errors in Coupled Ocean�Atmosphere Models
A new dataset synthesizes in situ and remote sensing observations from research ships deployed to the southeastern tropical Pacific stratocumulus region for 7 years in boreal fall. Surface meteorology, turbulent and radiative fluxes, aerosols, ...
Simon P. de Szoeke; Christopher W. Fairall; Daniel E. Wolfe; Ludovic Bariteau; Paquita Zuidema
Overland Precipitation Estimation from TRMM Passive Microwave Observations
Procedures for passive microwave precipitation estimation over land are investigated based on a large database of Tropical Rainfall Measuring Mission (TRMM) observations. The procedures include components for rain area delineation, convective/...
Mircea Grecu; Emmanouil N. Anagnostou
ARM tropical pacific experiment (ATPEX): Role of cloud, water vapor and convection feedbacks in the coupled ocean/atmosphere system
We have initiated studies that include radiation model validation, improved treatment of the three-dimensional structure of cloud-radiation interactions, and sensitivity runs that will unravel the role of cloud-convection-radiation interactions in the Pacific Sear Surface Temperatures and the overlying Walker and Hadley circulation. The research program is divided into three phases: (1) radiation, (2) cloud parameterization issues; (3) feedback and ocean-atmosphere interactions.
Ramanathan, V.; Barnett, T.P.
A Study of Cirrus Ice Particle Size Distribution Using TC4 Observations
An analysis of two days of in situ observations of ice particle size spectra, in convectively generated cirrus, obtained during NASA�s Tropical Composition, Cloud, and Climate Coupling (TC4) mission is presented. The observed spectra are examined ...
Lin Tian; Gerald M. Heymsfield; Lihua Li; Andrew J. Heymsfield; Aaron Bansemer; Cynthia H. Twohy; Ramesh C. Srivastava
A strategy for verifying near-convection-resolving model forecasts at observing sites
Routine verification of deterministic Numerical Weather Prediction (NWP) forecasts from the convection-permitting 4 km (UK4) and near-convection-resolving 1.5 km (UKV) configurations of the Met Office Unified Model (MetUM) has shown that it is ...
Marion P. Mittermaier
The West African Squall Line Observed on 23 June 1981 during COPT 81: Kinematics and Thermodynamics of the Convective Region
The squall line observed during the night of 23-24 June 1981 was one of the most intense events during the COPT 81 (COnvection Profonde Tropicale) experiment, conducted in May and June 1981 at Korhogo in the northern Ivory Coast by French and ...
Frank Roux
Observations of Elevated Convection Initiation Leading to a Surface-Based Squall Line during 13 June IHOP_2002
The evolution of a mesoscale convective system (MCS) observed during the International H2O Project that took place on the Great Plains of the United States is described. The MCS formed at night in a frontal zone, with four initiation episodes ...
John H. Marsham; Stanley B. Trier; Tammy M. Weckwerth; James W. Wilson
Radar Observations of Convective System Variability in Relationship to African Easterly Waves during the 2006 AMMA Special Observing Period
A radar-based analysis of the structure, motion, and rainfall variability of westward-propagating squall-line mesoscale convective systems (SLMCSs) in Niamey, Niger, during the African Monsoon Multidisciplinary Activities (AMMA) 2006 special ...
Rosana Nieto Ferreira; Thomas Rickenbach; Nick Guy; Earle Williams
A radar-based analysis of the structure, motion, and rainfall variability of westward-propagating squall-line mesoscale convective systems (SLMCSs) in Niamey, Niger, during the African Monsoon Multidisciplinary Activities ...
Williams, Earle R.
Convectively Coupled Waves in a Sheared Environment
A linear stability analysis, about a radiative�convective equilibrium in a sheared environment, on an equatorial beta plane, for a simple multicloud model for organized tropical convection is presented here. Both vertical/baroclinic and ...
Ying Han; Boualem Khouider
A Model for Transport across the Tropical Tropopause
A model of convective and advective transport across the tropical tropopause is described. In this model overshooting convective turrets inject dehydrated tropospheric air into a tropical �tropopause layer� (TTL) bounded approximately by the 50- ...
On the Modification Potential of Illinois Summertime Convective Clouds, with Comparisons to Florida and FACE Observations
The potential for enhancing rain output over central Illinois through modification of summertime convective clouds was investigated by use of model predictions of cumulus growth, as well as direct, internal measurements of cloud physical ...
Victor Wiggert; Robert I. Sax; Ronald L. Holle
Verification of Convection-Allowing WRF Model Forecasts of the Planetary Boundary Layer Using Sounding Observations
This study evaluates forecasts of thermodynamic variables from five convection-allowing configurations of the Weather Research and Forecasting Model (WRF) with the Advanced Research core (WRF-ARW). The forecasts vary only in their planetary ...
Michael C. Coniglio; James Correia Jr.; Patrick T. Marsh; Fanyou Kong
Convection and Easterly Wave Structures Observed in the Eastern Pacific Warm Pool during EPIC-2001
During September�October 2001, the East Pacific Investigation of Climate Processes in the Coupled Ocean�Atmosphere System (EPIC-2001) intertropical convergence zone (ITCZ) field campaign focused on studies of deep convection in the warm-pool ...
Walter A. Petersen; Robert Cifelli; Dennis J. Boccippio; Steven A. Rutledge; Chris Fairall
Comparison of Modeled and Observed Accumulated Convective Precipitation in Mountainous and Flat Land Areas
Convective precipitation is the main cause of extreme rainfall events in small areas. Its primary characteristics are both large spatial and temporal variability. For this reason, the monitoring of accumulated precipitation fields (liquid and ...
Mladjen ?uri?; Dejan Janc
Statistical Characteristics of Convective Storms in Belgium Derived from Volumetric Weather Radar Observations
High-resolution volumetric reflectivity measurements from a C-band weather radar are used to study the characteristics of convective storms in Belgium. After clutter filtering, the data are processed by the storm-tracking system Thunderstorm ...
Edouard Goudenhoofdt; Laurent Delobbe
Water and Energy Budgets of a Florida Mesoscale Convective System: A Combined Observational and Modeling Study
Mesoscale water and energy budgets are diagnosed for a squall line during the Convection and Precipitation Electrification Experiment and combined with the results of the two-dimensional Goddard Cumulus Ensemble Model. The fine temporal and ...
J. Halverson; M. Garstang; J. Scala; W-K. Tao
Numerical Simulation of Organized Convection. Part I: Model Description and Preliminary Comparisons with Squall Line Observations
A numerical model designed for the simulations of mesoscale flows perturbed by deep convective clouds is discussed. It is based on the time dependent coupling between a three-dimensional nonhydrostatic mesoscale model and a quasi-one-dimensional ...
Yves Pointin
An Observational Study of Convection Initiation on 12 June 2002 during IHOP_2002
The International H2O Project (IHOP_2002) was designed to sample the three-dimensional time-varying moisture field to better understand convective processes. Numerous research and operational water vapor measuring systems and retrievals, via in ...
Tammy M. Weckwerth; Hanne V. Murphey; Cyrille Flamant; Janine Goldstein; Crystalyne R. Pettet
Observations with Moored Acoustic Doppler Current Profilers in the Convection Regime in the Golfe du Lion
In the Golfe du Lion, south of France, favorable conditions for deep winter convection exist and were documented by the MEDOC experiments during 1969�75. A renewed investigation of that regime with upward-looking moored acoustic Doppler current ...
Friedrich Schott; Kevin D. Leaman
Some Observational Evidence for Dry Soils Supporting Enhanced Relative Humidity at the Convective Boundary Layer Top
The tendency of the relative humidity at the top of a clear convective boundary layer (RHtop) is studied as an indicator of cloud formation over a semiarid region within the conceptual framework introduced by Ek and Holtslag. Typically the ...
D. Westra; G. J. Steeneveld; A. A. M. Holtslag
Observational Study of a Convective Internal Boundary Layer over Lake Michigan
Using aircraft data collected during the University of Chicago Lake-Effect Snow Storm project, the results of a case study of the convective thermal internal boundary layer (TIBL) over Lake Michigan are presented. An intense cold air outbreak on ...
Sam S. Chang; Roscoe R. Braham Jr.
Observational Study of the Entrainment-Mixing Process in Warm Convective Clouds
Thermodynamical and microphysical measurements collected in convective clouds are examined within the frame of the homogeneous/inhomogeneous mixing concept, to determine how entrainment-mixing processes affect cloud droplets, their number ...
Fr�d�ric Burnet; Jean-Louis Brenguier
Summary of Convective Storm Initiation and Evolution during IHOP: Observational and Modeling Perspective
The data-rich International H2O Project (IHOP_2002) experiment is used to study convective storm initiation and subsequent evolution for all days of the experiment. Initiation episodes were almost evenly divided between those triggered along ...
James W. Wilson; Rita D. Roberts
Interactions between a Developing Mesoscale Convective System and Its Environment. Part I: Observational Analysis
This paper is the first in a two part series in which the interactions between a growing mesoscale convective system (MCS) and its surrounding environment are investigated. The system studied here developed in northeastern Colorado on 19 July ...
Polarimetric Radar Observations of Convection in Northwestern Mexico during the North American Monsoon Experiment
The spatial and temporal variability of convection during the North American Monsoon Experiment (NAME) was examined via analysis of three-dimensional polarimetric radar data. Terrain bands were defined as the Gulf of California (over water) and ...
Timothy J. Lang; Steven A. Rutledge; Robert Cifelli
TRMM Observations of Intraseasonal Variability in Convective Regimes over the Amazon
This study utilizes the Tropical Rainfall Measuring Mission (TRMM) satellite precipitation radar (PR), lightning imaging sensor (LIS), and passive microwave imager (TMI) data together with ground-based lightning data to investigate the vertical ...
Walter A. Petersen; Stephen W. Nesbitt; Richard J. Blakeslee; Robert Cifelli; Paul Hein; Stephen A. Rutledge
Application of Airborne Passive Microwave Observations for Monitoring Inland Flooding Caused by Tropical Cyclones
Inland flooding from tropical cyclones is a significant factor in storm-related deaths in the United States and other countries, with the majority of tropical cyclone fatalities recorded in the United States resulting from freshwater flooding. ...
Courtney D. Buckley; Robbie E. Hood; Frank J. LaFontaine
Observed Self-Similarity of Precipitation Regimes over the Tropical Oceans
A K-means clustering algorithm was used to classify Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) scenes within 1� square patches over the tropical (15�S�15�N) oceans. Three cluster centroids or �regimes� that minimize the ...
Gregory S. Elsaesser; Christian D. Kummerow; Tristan S. L�Ecuyer; Yukari N. Takayabu; Shoichi Shige
An Observational Study of Tropical�Midlatitude Interaction on Intraseasonal Time Scales during Winter
Eight Northern Hemisphere winters of five- and ten-day average midlatitude 500 mb heights and tropical outgoing IR are used in a correlative study of tropical-midlatitude interaction. The seasonal cycle and interannual variability are removed so ...
Brant Liebmann; Dennis L. Hartmann
Observational Analysis of Tropical Cyclone Formation. Part I: Basic Description of Data Sets
Twelve composite data sets are constructed from rawinsonde data in the tropical northwest Pacific and tropical northwest Atlantic Oceans. Each data set is a composite average of approximately 80 individual disturbances. Four different types of ...
John L. McBride
Mechanisms for Diurnal Variability of Global Tropical Rainfall Observed from TRMM
The behavior and various controls of diurnal variability in tropical�subtropical rainfall are investigated using Tropical Rainfall Measuring Mission (TRMM) precipitation measurements retrieved from the three level-2 TRMM standard profile ...
Clouds in Tropical Cyclones
Clouds within the inner regions of tropical cyclones are unlike those anywhere else in the atmosphere. Convective clouds contributing to cyclogenesis have rotational and deep intense updrafts but tend to have relatively weak downdrafts. Within the ...
Clouds within the inner regions of tropical cyclones are unlike those anywhere else in the atmosphere. Convective clouds contributing to cyclogenesis have rotational and deep intense updrafts but tend to have relatively weak downdrafts. Within ...
A Radar and Electrical Study of Tropical �Hot Towers�
Radar and electrical measurements for deep tropical convection are examined for both �break period� and �monsoonal� regimes in the vicinity of Darwin, Australia. Break period convection consists primarily of deep continental convection, whereas ...
E. R. Williams; S. G. Geotis; N. Renno; S. A. Rutledge; E. Rasmussen; T. Rickenbach
ARM - Publications: Science Team Meeting Documents: Tropical Warm Pool
Tropical Warm Pool International Cloud Experiment Tropical Warm Pool International Cloud Experiment May, Peter Bureau or Meteorology Research Centre Mather, James Pacific Northwest National Laboratory Jakob, Christian BMRC One of the most complete data sets describing tropical convection ever collected will result from the upcoming Tropical Warm Pool International Cloud Experiment (TWPICE) in the area around Darwin in late 2005 and early 2006. The aims of the experiment will be to examine convective cloud systems from their initial stages through to the decay of the cirrus generated and to measure their impact on the environment. The experiment design includes an unprecedented network of ground-based observations (soundings, active and passive remote sensors) combined with a large range of low, mid and high altitude aircraft for in-situ and remote sensing
An Observational Study of Mesoscale Convective Systems with Heavy Rainfall over the Korean Peninsula
A heavy rainfall event induced by mesoscale convective systems (MCSs) occurred over the middle Korean Peninsula from 25 to 27 July 1996. This heavy rainfall caused a large loss of life and property damage as a result of flash floods and ...
Hyung Woo Kim; Dong Kyou Lee
Observing Deep Convection in the Labrador Sea during Winter 1994/95
A 12-month mooring record (May 1994�June 1995), together with accompanying PALACE float data, is used to describe an annual cycle of deep convection and restratification in the Labrador Sea. The mooring is located at 56.75�N, 52.5�W, near the ...
Jonathan M. Lilly; Peter B. Rhines; Martin Visbeck; Russ Davis; John R. N. Lazier; Friedrich Schott; David Farmer
Initiation of Convective Storms at Radar-Observed Boundary-Layer Convergence Lines
The origin of 653 convective storms occurring over a 5000 km2 area immediately east of the Colorado Rocky Mountains from 18 May to 15 August 1984 was examined. Seventy-nine percent of the 418 storms that initiated within the study area occurred ...
James W. Wilson; Wendy E. Schreiber
Statistical Location and Timing of the Convective Lines off the Mountainous Coast of Southeastern Taiwan from Long-Term Radar Observations
In this study, observations from the C-band Doppler radar on Green Island, which is located off the southeastern coast of Taiwan, during 1998�2004 were analyzed to investigate the statistical characteristics of the convective lines occurring off ...
Cheng-Ku Yu; Che-Yu Lin
Prediction and Diagnosis of Tropical Cyclone Formation in an NWP System. Part I: The Critical Role of Vortex Enhancement in Deep Convection
This is the first of a three-part investigation into tropical cyclone (TC) genesis in the Australian Bureau of Meteorology�s Tropical Cyclone Limited Area Prediction System (TC-LAPS), an operational numerical weather prediction (NWP) forecast ...
K. J. Tory; M. T. Montgomery; N. E. Davidson
Microwave Radiometric Observations Near 19.35, 92 and 183 GHz of Precipitation in Tropical Storm Cora
Observations of rain cells in the remains of a decaying tropical storm were made by Airborne Microwave Radiometers at 19.35 and 92 GHz and three frequencies near 183 GHz. Extremely low brightness temperatures, as low as 140 K, were noted in the ...
T. T. Wilheit; A. T. C. Chang; J. L. King; E. B. Rodgers; R. A. Nieman; B. M. Krupp; A. S. Milman; J. S. Stratigos; H. Siddalingaiah
Ten Years of Measurements of Tropical Upper-Tropospheric Water Vapor by MOZAIC. Part I: Climatology, Variability, Transport, and Relation to Deep Convection
Ten years (1994�2004) of measurements of tropical upper-tropospheric water vapor (UTWV) by the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) are investigated over three regions�the tropical Atlantic, tropical Africa, ...
Zhengzhao Luo; Dieter Kley; Richard H. Johnson; Herman Smit
Vertically pointing millimeter-wavelength radar observations of anvil clouds extending from mesoscale convective systems (MCSs) that pass over an Atmospheric Radiation Measurement Program (ARM) field site in Niamey, Niger, are compared to anvil structures generated by the Weather Research and Forecasting (WRF) mesoscale model using six different microphysical schemes. The radar data provide the statistical distribution of the radar reflectivity values as a function of height and anvil thickness. These statistics are compared to the statistics of the modeled anvil cloud reflectivity at all altitudes. Requiring the model to be statistically accurate at all altitudes is a stringent test of the model performance. The typical vertical profile of radiative heating in the anvil clouds is computed from the radar observations. Variability of anvil structures from the different microphysical schemes provides an estimate of the inherent uncertainty in anvil radiative heating profiles. All schemes underestimate the optical thickness of thin anvils and cirrus, resulting in a bias of excessive net anvil heating in all of the simulations.
Powell, Scott W.; Houze, R.; Kumar, Anil; McFarlane, Sally A.
Genesis of Tropical Storm Eugene (2005) from Merging Vortices Associated with ITCZ Breakdowns. Part I: Observational and Modeling Analyses
Although tropical cyclogenesis occurs over all tropical warm ocean basins, the eastern Pacific appears to have the highest frequency of tropical cyclogenesis events per unit area. In this study, tropical cyclogenesis from merging mesoscale ...
Chanh Q. Kieu; Da-Lin Zhang
Observed Evolution of Northward-Propagating Intraseasonal Variation over the Western Pacific: A Case Study in Boreal Early Summer
This report describes the in situ observed evolution of the atmospheric profile during an event of the boreal summer intraseasonal variation (BSISV) in the tropical western Pacific Ocean. The convectively active region of the BSISV proceeded ...
Masaki Katsumata; Hiroyuki Yamada; Hisayuki Kubota; Qoosaku Moteki; Ryuichi Shirooka
On How Hot Towers Fuel the Hadley Cell: An Observational and Modeling Study of Line-Organized Convection in the Equatorial Trough from TOGA COARE
An airflow trajectory analysis was carried out based on an idealized numerical simulation of the nocturnal 9 February 1993 equatorial oceanic squall line observed over the Tropical Ocean and Global Atmosphere Coupled Ocean�Atmosphere Response ...
Alexandre O. Fierro; Joanne Simpson; Margaret A. LeMone; Jerry M. Straka; Bradley F. Smull
Wind Profiler Observations of Vertical Motion and Precipitation Microphysics of a Tropical Squall Line
Data from a wind profiler located at Darwin, Australia, have been used to examine the vertical motions and precipitation microphysics in a well-developed squall line. Both a mature and developing convective cell are well sampled. The vertical ...
Peter T. May; Deepak K. Rajopadhyaya
Doppler Radar and Lightning Network Observations of a Severe Outbreak of Tropical Cyclone Tornadoes
Data from a single Weather Surveillance Radar-1988 Doppler (WSR-88D) and the National Lightning Detection Network are used to examine the characteristics of the convective storms that produced a severe tornado outbreak, including three tornadoes ...
Eugene W. McCaul Jr.; Dennis E. Buechler; Steven J. Goodman; Michael Cammarata
Numerical Simulations and Observations of Surface Wave Fields under an Extreme Tropical Cyclone
The performance of the wave model WAVEWATCH III under a very strong, category 5, tropical cyclone wind forcing is investigated with different drag coefficient parameterizations and ocean current inputs. The model results are compared with field ...
Yalin Fan; Isaac Ginis; Tetsu Hara; C. Wayne Wright; Edward J. Walsh
Storm-Relative Observations in Tropical Cyclone Data Assimilation with an Ensemble Kalman Filter
A storm-relative data assimilation method for tropical cyclones is introduced for the ensemble Kalman filter, using the Hurricane Weather Research and Forecasting (HWRF) Ensemble Data Assimilation System (HEDAS) developed at the Hurricane Research ...
Altu? Aksoy
Observed Structure and Propagation Characteristics of Tropical Summertime Synoptic Scale Disturbances
The three-dimensional structure and propagation characteristics of tropical synoptic scale transients during the northern summer we studied with twice daily ECMWF global gridded analyses for the 1980�1987 period. Regions of enhanced variability ...
Kai-Hon Lau; Ngar-Cheung Lau
A Census of Precipitation Features in the Tropics Using TRMM: Radar, Ice Scattering, and Lightning Observations
An algorithm has been developed to identify precipitation features (?75 km2 in size) in two land and two ocean regions during August, September, and October 1998. It uses data from two instruments on the Tropical Rainfall Measuring Mission (TRMM) ...
Stephen W. Nesbitt; Edward J. Zipser; Daniel J. Cecil
Tropical Cyclone Data Impact Studies: Influence of Model Bias and Synthetic Observations
The impacts of assimilating dropwindsonde data and enhanced atmospheric motion vectors (AMVs) on tropical cyclone track forecasts are examined using the Navy global data assimilation and forecasting systems. Enhanced AMVs have the largest impact ...
Carolyn A. Reynolds; Rolf Langland; Patricia M. Pauley; Christopher Velden
Tropical Cyclone-like Vortices in a Limited Area Model: Comparison with Observed Climatology
A climate simulation of a limited area model implemented over the Australian region is analyzed for the presence of low pressure systems that have some of the physical characteristics of tropical cyclones. The model is run at a horizontal ...
Kevin Walsh; Ian G. Watterson
Polarimetric Radar Observations of the Persistently Asymmetric Structure of Tropical Cyclone Ingrid
Tropical Cyclone Ingrid had a distinctly asymmetric reflectivity structure with an offshore maximum as it passed parallel to and over an extended coastline near a polarimetric weather radar located near Darwin, northern Australia. For the first ...
Peter T. May; J. D. Kepert; T. D. Keenan
A 10-Year Climatology of Tropical Radiative Heating and Its Vertical Structure from TRMM Observations
This paper outlines recent advances in estimating atmospheric radiative heating rate profiles from the sensors aboard the Tropical Rainfall Measuring Mission (TRMM). The approach employs a deterministic framework in which four distinct retrievals ...
Tristan S. L�Ecuyer; Greg McGarragh
A Numerical Study of the Genesis of Tropical Storms Observed during the FGGE Year
This study utilizes the First GARP Global Experiment's (FGGE) analyzed dataset and a relatively fine scale regional model in combination to investigate the feasibility of numerically simulating tropical disturbances during the FGGE year, 1979. ...
Robert E. Tuleya
Observed versus GCM-Generated Local Tropical Cyclone Frequency: Comparisons Using a Spatial Lattice
Of broad scientific and public interest is the reliability of global climate models (GCMs) to simulate future regional and local tropical cyclone (TC) occurrences. Atmospheric GCMs are now able to generate vortices resembling actual TCs, but ...
Sarah Strazzo; James B. Elsner; Timothy LaRow; Daniel J. Halperin; Ming Zhao
Comparison of Precipitable Water Observations in the Near Tropics by GPS, Microwave Radiometer, and Radiosondes
The sensing of precipitable water (PW) using the Global Positioning System (GPS) in the near Tropics is investigated. GPS data acquired from the Central Weather Bureau�s Taipei weather station in Banchao (Taipei), Taiwan, and each of nine ...
Yuei-An Liou; Yu-Tun Teng; Teresa Van Hove; James C. Liljegren
Observational Analysis of Tropical Cyclogenesis in the Western North Pacific. Part II: Budget Analysis
This is the second of a two-part study which uses a combination of composite rawinsonde and individual FGGE case analyses to identify the important physical processes associated with tropical cyclone formation. Part I examined the structural ...
Cheng Shang Lee
Comparisons of GCM and Observed Surface Wind Fields over the Tropical Indian and Pacific Oceans
Many of the processes that have important effects on both the climatological distribution and interannual variability of sea surface temperatures (SSTs) in the tropical oceans are greatly affected by the surface wind field. For this reason ...
Nicholas E. Graham; Tim P. Barnett; Robert M. Chervin; Michael E. Schlesinger; Ulrich Schlese
Effect of Tropical Waves on the Tropical Tropopause Transition Layer Upwelling
An initial-value problem is employed with a GCM to investigate the role of the convectively driven Rossby and Kelvin waves for tropopause transition layer (TTL) upwelling in the tropics. The convective heating is mimicked with a prescribed ...
Jung-Hee Ryu; Sukyoung Lee
Orogenic Convection in Subtropical South America as Seen by the TRMM Satellite
Extreme orogenic convective storms in southeastern South America are divided into three categories: storms with deep convective cores, storms with wide convective cores, and storms containing broad stratiform regions. Data from the Tropical ...
Kristen L. Rasmussen; Robert A. Houze Jr.
Characterization of Momentum Transport Associated with Organized Moist Convection and Gravity Waves
Tropical convection is inherently multiscalar, involving complex fields of clouds and various regimes of convective organization ranging from small disorganized cumulus up to large organized convective clusters. In addition to being a crucial ...
A Mesoscale Gravity Wave Event Observed during CCOPE. Part II: Interactions between Mesoscale Convective Systems and the Antecedent Waves
This paper presents the results of a very detailed investigation into the effects of preexisting gravity waves upon convective systems, as well as the feedback effects of convection of varying intensity upon the waves. The analysis is based on ...
Steven E. Koch; Robert E. Golus; Paul B. Dorian
Correction of Radar QPE Errors for Non-Uniform VPRs in Mesoscale Convective Systems Using TRMM Observations
Mesoscale Convective Systems (MCSs) contain both regions of convective and stratiform precipitation, and a bright band (BB) is often found in the stratiform region. Inflated reflectivity intensities in the BB often cause positive biases in radar ...
Youcun Qi; Jian Zhang; Qing Cao; Yang Hong; Xiao-Ming Hu
An Objective Algorithm for Detecting and Tracking Tropical Cloud Clusters: Implications for Tropical Cyclogenesis Prediction
An algorithm to detect and track global tropical cloud clusters (TCCs) is presented. TCCs are organized large areas of convection that form over warm tropical waters. TCCs are important because they are the �seedlings� that can evolve into ...
Christopher C. Hennon; Charles N. Helms; Kenneth R. Knapp; Amanda R. Bowen
The Importance of Three Physical Processes in a Minimal Three-Dimensional Tropical Cyclone Model
The minimal three-dimensional tropical cyclone model developed by Zhu et al. is used to explore the role of shallow convection, precipitation-cooled downdrafts, and the vertical transport of momentum by deep convection on the dynamics of tropical ...
Hongyan Zhu; Roger K. Smith
Uncertainty Quantification and Parameter Tuning in the CAM5 Zhang-McFarlane Convection Scheme and Impact of Improved Convection on the Global Circulation and Climate
In this study, we applied an uncertainty quantification (UQ) technique to improve convective precipitation in the global climate model, the Community Atmosphere Model version 5 (CAM5), in which the convective and stratiform precipitation partitioning is very different from observational estimates. We examined the sensitivity of precipitation and circulation to several key parameters in the Zhang-McFarlane deep convection scheme in CAM5, using a stochastic importance-sampling algorithm that can progressively converge to optimal parameter values. The impact of improved deep convection on the global circulation and climate was subsequently evaluated. Our results show that the simulated convective precipitation is most sensitive to the parameters of the convective available potential energy consumption time scale, parcel fractional mass entrainment rate, and maximum downdraft mass flux fraction. Using the optimal parameters constrained by the observed Tropical Rainfall Measuring Mission, convective precipitation improves the simulation of convective to stratiform precipitation ratio and rain-rate spectrum remarkably. When convection is suppressed, precipitation tends to be more confined to the regions with strong atmospheric convergence. As the optimal parameters are used, positive impacts on some aspects of the atmospheric circulation and climate, including reduction of the double Intertropical Convergence Zone, improved East Asian monsoon precipitation, and improved annual cycles of the cross-equatorial jets, are found as a result of the vertical and horizontal redistribution of latent heat release from the revised parameterization. Positive impacts of the optimal parameters derived from the 2 simulations are found to transfer to the 1 simulations to some extent.
Yang, Ben; Qian, Yun; Lin, Guang; Leung, Lai-Yung R.; Rasch, Philip J.; Zhang, Guang J.; McFarlane, Sally A.; Zhao, Chun; Zhang, Yaocun; Wang, Hailong; Wang, Minghuai; Liu, Xiaohong
Convection in TOGA COARE: Horizontal Scale, Morphology, and Rainfall Production
The occurrence frequency and rainfall production of mesoscale convective systems (MCSs) relative to smaller groups of convective clouds over the tropical oceans is not well known. Eighty days of shipboard radar data collected during the recent ...
Thomas M. Rickenbach; Steven A. Rutledge
Physics of Greenhouse Effect and Convection in Warm Oceans
Sea surface temperature (SST) in roughly 50% of the tropical Pacific Ocean is warm enough (SST > 300 K) to permit deep convection. This paper examines the effects of deep convection on the climatological mean vertical distributions of water vapor ...
A. K. Inamdar; V. Ramanathan
Regulation of Moist Convection over the West Pacific Warm Pool
The mechanisms that regulate moist convection over the warm tropical oceans are not well understood. One school of thought holds that convection is caused by the convergence of moisture, which in turn is produced by an independent dynamical ...
David J. Raymond
Analysis of Convection and Its Association with African Easterly Waves
The association between convection and African easterly wave (AEW) activity over tropical Africa and the tropical Atlantic during the boreal summer is examined using satellite brightness temperature (TB) and ECMWF reanalysis datasets. Spectral ...
Ademe Mekonnen; Chris D. Thorncroft; Anantha R. Aiyyer
Observed Tropical Cyclone Eye Thermal Anomaly Profiles Extending Above 300 hPa
As recently pointed out by Stern and Nolan (2012), much of our knowledge of the warm core structure of the tropical cyclone eye has come from composites of in situ data taken from multiple aircraft studies of three storms in the late 1950�s and ...
Stephen L. Durden
A Multidiagnostic Intercomparison of Tropical-Width Time Series Using Reanalyses and Satellite Observations
Poleward migration of the latitudinal edge of the tropics of 0.25��3.0� decade?1 has been reported in several recent studies based on satellite and radiosonde data and reanalysis output covering the past ~30 yr. The goal of this paper is to ...
Sean M. Davis; Karen H. Rosenlof
GPS Dropwindsonde and WSR-88D Observations of Tropical Cyclone Vertical Wind Profiles and Their Characteristics
The characteristics of tropical cyclone vertical wind profiles and their associated wind speed peaks below 1.5 km were examined through the use of a large number of GPS dropwindsondes (GPS sondes) and radar-derived velocity�azimuth display (VAD) ...
Ian M. Giammanco; John L. Schroeder; Mark D. Powell
Heat, Moisture, and Momentum Budgets of Isolated Deep Midlatitude and Tropical Convective Clouds as Diagnosed from Three-Dimensional Model Output. Part I: Control Experiments
This project uses a three-dimensional anelastic cloud model with a simple ice phase parameterization to evaluate the feedback between isolated deep convective clouds and their near surroundings. The horizontal Reynolds averaging approach of ...
Robert E. Schlesinger
Parameter study of tropical cyclones in rotating radiative-convective equilibrium with column physics and resolution of a 25 km GCM
Rotating radiative-convective equilibrium is studied by extracting the column physics of a meso-scale resolution global atmospheric model that simulates realistic hurricane frequency statistics and coupling it to rotating hydrostatic dynamics in ...
Wenyu Zhou; Isaac M. Held; Stephen T. Garner
The convective structures associated with cloud-to-ground lightning in TOGA COARE Mesoscale Convective Systems
The TOGA COARE experiment was carried out in the western Pacific warm pool region from November 1992 through February 1993. Data from TOGA COARE provide the opportunity for comprehensive studies of tropical oceanic convection. This study seeks to understand more about the structures of tropical mesoscale convective systems in relation to their lightning activity and cold cloud area. The properties of convective cores within the MCSs, as well as their infrared (IR) cloud top temperatures are related to cloud-to-ground lightning. IR and lightning time histories for each case are compared, and the cases ranked by mean flashes per 10000 km2. For selected cases, radar/lightning overlays and vertical profiles of maximum radar reflectivities (VPRRs) are shown in order to describe the convective structures of cells that produced lightning, and also cells that did not produce lightning. IR cloud-top temperature and lightning histories indicate the highly variable nature of the TOGA COARE MCSs. Some MCSs which have very cold cloud-top temperatures have little or no lightning. When a system did produce lightning, more flashes generally occurred during its growth phase. Overall, IR measurements seem to be a poor indicator of lightning due to the lack of a clear relationship between the size of cold cloud-top area and cloud-to-ground flashes. The overall flash rates of the TOGA COARE MCSs support previous work which showed that tropical oceanic convection has an order of magnitude less cloud-to-ground lightning than continental convection. In fact, the highest flash rate for the 13 cases was less than the weakest continental case in a Texas MCS study (Toracinta et al. 1995). Examination of individual VPRR and of all convective VPRR from the 13 cases indicate a pronounced difference between lightning producing and non-lightning producing cells. Lightning producing convective cells have higher radar reflectivity in the 5.0- 8.0 km layer, and a slower decrease with height, both observations indicating larger ice particles in the mixed phase region between 00 C and-200 C.
Restivo, Michael Edward
Simulations of Physical Retrieval of Tropical Cyclone Thermal Structure Using 55-GHz Band Passive Microwave Observations from Polar-Orbiting Satellites
A method for estimating the horizontal structure of the upper-tropospheric warm anomaly of tropical cyclones from 55-GHz microwave observations is presented. Because the peak warming occurs over an area smaller than that viewed by current and ...
Robert T. Merrill
Joint Impact of Forecast Tendency and State Error Biases in Ensemble Kalman Filter Data Assimilation of Inner-Core Tropical Cyclone Observations
In this study the properties and causes of systematic errors in high-resolution data assimilation of inner-core tropical cyclone (TC) observations were investigated using the Hurricane Weather Research and Forecasting (HWRF) Ensemble Data ...
Tomislava Vukicevic; Altu? Aksoy; Paul Reasor; Sim D. Aberson; Kathryn J. Sellwood; Frank Marks
Distant Effects of a Recurving Tropical Cyclone on Rainfall in a Midlatitude Convective System: A High-Impact Predecessor Rain Event
Recent research has identified predecessor rain events (PREs), which are mesoscale regions of heavy rainfall that occur 1000 km poleward and downshear of recurving tropical cyclones (TCs). PREs typically occur 24�36 h prior to the arrival of the ...
Russ S. Schumacher; Thomas J. Galarneau Jr.; Lance F. Bosart
Tropical Cyclone Forecasting Applications of the GOES WMSI
The Geostationary Operational Environmental Satellite (GOES) sounder-derived Wet Microburst Severity Index (WMSI) was originally developed and implemented to assess the potential magnitude of convective downbursts over the central and eastern continental United States. The WMSI algorithm incorporates convective available potential energy (CAPE), to parameterize static instability, as well as the vertical theta-e (equivalent potential temperature) difference (TeD) between the surface and mid-troposphere to infer the presence of a mid-level dry air layer. It has been noted with two recent landfalling hurricanes over the Florida Gulf of Mexico coast that the GOES WMSI product accurately predicted downburst magnitude associated with convective bands and the eye wall. As a convective system, it is expected that tropical cyclones can be profilic downburst producing storms. In fact, several severe downbursts were observed in association with the pre-hurricane squall line and remnant eye wall of Hurricane Charley (Au...
Pryor, K L
Initialization of a Cloud-Resolving Model with Airborne Doppler Radar Observations of an Oceanic Tropical Convective System
Doppler radar�derived fields of wind and reflectivity, retrieved temperature perturbations, estimated water vapor, and cloud water contents are used to initialize a nonhydrostatic cloud-resolving model. Airborne Doppler data collected in a ...
Soline Bielli; Frank Roux
Understanding Convective Extreme Precipitation Scaling Using Observations and an Entraining Plume Model
Previously observed twice Clausius-Clapeyron (2CC) scaling for extreme precipitation at hourly timescales has led to discussions about its origin. The robustness of this scaling is assessed by analyzing a sub-hourly dataset of 10-minute resolution ...
Jessica M. Loriaux; Geert Lenderink; Stephan R. De Roode; A. Pier Siebesma
The Climode Field Campaign: Observing the Cycle of Convection and Restratification over the Gulf Stream
A major oceanographic field experiment is described, which is designed to observe, quantify, and understand the creation and dispersal of weakly stratified fluid known as �mode water� in the region of the Gulf Stream. Formed in the wintertime by ...
The Climode Group:J. Marshall; R. Ferrari; G. Forget; G. Maze; A. Andersson; N. Bates; W. Dewar; S. Doney; D. Fratantoni; T. Joyce; F. Straneo; J. Toole; R. Weller; J. Edson; M. Gregg; K. Kelly; S. Lozier; J. Palter; R. Lumpkin; R. Samelson; E. Skyllingstad; K. Silverthorne; L. Talley; L. Thomas
Unusually Long Duration, Multiple-Doppler Radar Observations of a Front in a Convective Boundary Layer
Dual-Doppler observations acquired by a network of mobile radars deployed in the Oklahoma panhandle on 3 June 2002 are used to document the kinematic structure and evolution of a front. The data were collected during the International H2O Project ...
John R. Stonitsch; Paul M. Markowski
Analysis of the Tropical Tropopause Layer Cirrus in CALIPSO and MLS Data - A Water Perspective
Two mechanisms appear to be primarily responsible for the formation of cirrus clouds in Tropical Tropopause Layer (TTL): detrainment from deep convective anvils and in situ initiation. Here we propose to identify TTL cirrus clouds by analyzing water content measurements from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and Aura Microwave Limb Sounder (MLS). Using ice water content (IWC) and water vapor (H2O) abundances we identify TTL cirrus clouds that contain too much ice to have been formed in situ � and therefore must be of convective origin. We use two methods to infer amounts of water vapor available for in situ formation. Clouds with IWC greater than this threshold are categorized as being of convective origin; clouds with IWC below the threshold are ambiguous � they could either form from in situ or still be of convective origin. Applying the thresholds from December 2008 to November 2009, we found that at least 19.2% of tropical cirrus were definitively of convective origin at the tropopause (375 K) during boreal winter. At each level, we found three maxima in the occurrence of convective cirrus: western Pacific, equatorial Africa, and South America. Averaged over the entire tropics (30oS to 30oN), we found convective cirrus occurs more frequently in boreal winter and less frequently in boreal summer, basically following the a decreasing trend from DJF, MAM, SON, to JJA. During boreal summer, we found that only 4.6% of tropical cirrus come from convection. Sensitivity tests show that the thresholds derived at 390 K have the largest uncertainty. At lower levels, especially 375 K, our thresholds are robust.
Wang, Tao
Soil Moisture Impacts on Convective Margins
An idealized prototype for the location of the margins of tropical land region convection zones is extended to incorporate the effects of soil moisture and associated evaporation. The effect of evaporation, integrated over the inflow trajectory ...
Benjamin R. Lintner; J. David Neelin
The Influence of Tropical heating Displacements on the Extratropical Climate
The hypothesis is advanced that a latitudinal shift in the tropical convective heating pattern can significantly alter temperatures in the extratropics. Results of a simplified GCM show that the shift of a prescribed tropical heating toward the ...
Arthur Y. Hou
On the Wave Spectrum Generated by Tropical Heating
Convective heating profiles are computed from one month of rainfall rate and cloud-top height measurements using global Tropical Rainfall Measuring Mission and infrared cloud-top products. Estimates of the tropical wave response to this heating ...
David A. Ortland; M. Joan Alexander; Alison W. Grimsdell
Intraseasonal Behavior of Clouds, Temperature, and Motion in the Tropics
The spectral character of tropical convection is investigated in an 11-yr record of outgoing longwave radiation from the Advanced Very High Resolution Radiometer to identify interaction with the tropical circulation. Along the equator in the ...
Murry L. Salby; Harry H. Hendon
Convection Patterns in a Pond
Unusual convection patterns were observed in snow-slush an a pond in Seattle, Wash., during January 1980 and again during February 1981. The patterns are reminiscent of spoke-type convection discovered experimentally by Busse and Whitehead (1974)...
Kristina B. Katsaros
A Diagnostic Study of the Intensity of Three Tropical Cyclones in the Australian Region. Part I: A Synopsis of Observed Features of Tropical Cyclone Kathy (1984)
Objective streamline analyses and digitized high-resolution IR satellite cloud data have been used to examine in detail the changes in the environmental circulation and in the cloud structure that took place in and around Tropical Cyclone Kathy (...
France Lajoie; Kevin Walsh
A Climatology of Tropical Anvil and Its Relationship to the Large-Scale Circulation
This dissertation uses multiple tools to investigate tropical anvil, i.e., thick, non-precipitating cloud associated with deep convection with the main objectives to provide a climatology of tropics-wide anvil properties and a better understanding of anvil formation, and to provide a more realistic assessment of the radiative impact of tropical anvil on the large-scale circulation. Based on 10 years (1998-2007) of observations, anvil observed by the Tropical Rainfall Measuring Mission (TRMM) Precipitation (PR) shows significant geographical variations, which can be linked to variations in the parent convection. Strong upper level wind shear appears to assist the generation of anvil and may further explain the different anvil statistics over land and ocean. Variations in the large-scale environment appear to play a more important role in anvil production in regions where convection regularly attains heights greater than 7 km. For regions where convection is less deep, variations in the depth of the convection and the large-scale environment likely contribute more equally to anvil generation. Anvil radiative heating profiles are estimated by extrapolating millimeter cloud radar (MMCR) radiative properties from Manus to the 10-year TRMM PR record. When the unconditional anvil areal coverage is taken into account, the anvil radiative heating becomes quite weak, increasing the PR latent heating profile by less than 1 percent at mid and upper levels. Stratiform rain and cirrus radiative heating contributions increase the upper level latent heating by 12 percent. This tropical radiative heating only slightly enhances the latent heating driven model response throughout the tropics, but more significantly over the East Pacific. These modest circulation changes suggest that previous studies may have overemphasized the importance of radiative heating in terms of Walker and Hadley circulation variations. Further, the relationship of cloud radiative heating to latent heating needs to be taken into account for more realistic studies of cloud radiative forcing on the large-scale circulation.
Li, Wei
Diurnal Variation of Precipitation over the Tropical Oceans Observed by TRMM/TMI Combined with SSM/I
The Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) data are used in this study as the first passive microwave information from a precessing orbit to reveal diurnal variations of precipitation over the tropical oceans (30�S�30�N)...
Keiji Imaoka; Roy W. Spencer
SOFAR Float Observations of an Intermediate-Depth Eastern Boundary Current and Mesoscale Variability in the Eastern Tropical Atlantic Ocean
Two neutrally buoyant SOFAR floats vigorously looped and meandered at depths of 950�1150 m in the eastern tropical Atlantic Ocean. The float trajectories illustrate a poleward flow along the tropical eastern boundary and significant intermediate-...
David M. Fratantoni; Philip L. Richardson
A transilient matrix for moist convection
A method is introduced for diagnosing a transilient matrix for moist convection. This transilient matrix quantifies the nonlocal transport of air by convective eddies: for every height z, it gives the distribution of starting heights z{prime} for the eddies that arrive at z. In a cloud-resolving simulation of deep convection, the transilient matrix shows that two-thirds of the subcloud air convecting into the free troposphere originates from within 100 m of the surface. This finding clarifies which initial height to use when calculating convective available potential energy from soundings of the tropical troposphere.
Romps, D.; Kuang, Z.
An Estimation of the Condensation Rates in Three Severe Storm Systems from Satellite Observations of the Convective Mass Flux
A technique was developed for estimating the condensation rates of convective storms using satellite measurements of cirrus anvil expansion rates and radiosonde measurements of environmental water vapor. Three cases of severe conviction in ...
Robert A. Mack; Donald P. Wylie
Evaluation of an LES-Based Wind Profiler Simulator for Observations of a Daytime Atmospheric Convective Boundary Layer
The daytime atmospheric convective boundary layer (CBL) is characterized by strong turbulence that is primarily caused by buoyancy forced from the heated underlying surface. The present study considers a combination of a virtual radar and large ...
Danny E. Scipi�n; Phillip B. Chilson; Evgeni Fedorovich; Robert D. Palmer
Observations of Deep Convection in the Gulf of Lions, Northern Mediterranean, during the Winter of 1991/92
During December 1991 to April 1992 measurements with moored acoustic Doppler current profiler (ADCP) stations and shipboard surveys were carried out in the convection regime of the Gulf of Lions, northwestern Mediterranean. First significant ...
Friedrich Schott; Martin Visbeck; Uwe Send; J�rgen Fischer; Lothar Stramma; Yves Desaubies
Microphysical and Thermodynamic Structure and Evolution of the Trailing Stratiform Regions of Mesoscale Convective Systems during BAMEX. Part I: Observations
This study used airborne and ground-based radar and optical array probe data from the spiral descent flight patterns and horizontal flight legs of the NOAA P-3 aircraft in the trailing stratiform regions (TSRs) of mesoscale convective systems (...
Andrea M. Smith; Greg M. McFarquhar; Robert M. Rauber; Joseph A. Grim; Michael S. Timlin; Brian F. Jewett; David P. Jorgensen
Observed Structure of Convectively Coupled Waves as a Function of Equivalent Depth: Kelvin Waves and the Madden�Julian Oscillation
The view that convectively coupled Kelvin waves and the Madden�Julian oscillation (MJO) are distinct modes is tested by regressing data from the Climate Forecast System Reanalysis against satellite outgoing longwave radiation data filtered for ...
Paul E. Roundy
Turbulence Structure of the Convective Boundary Layer. Part II. Phonenix 78 Aircraft Observations of Thermals and Their Environment
A conditional sampling technique based upon the mixed layer spectra of vertical velocity and temperature is developed. This technique is used to analyze the turbulence data obtained by aircraft during the Phoenix 78 convective boundary layer ...
George S. Young
The multiple vortex nature of tropical cyclogenesis
This thesis contains an observational analysis of the genesis of Tropical Storm Allison (2001). Using a paradigm of tropical cyclone formation as the superposition of potential vorticity (PV) anomalies, the importance of different scales of PV merger to various aspects of Allison?s formation is discussed. While only the case of Allison is discussed in great detail, other studies have also documented PV superposition on various scales, and superposition could be important for most tropical cyclones. Preceding Allison?s genesis, PV superposition on the large scale destabilized the atmosphere and increased low-level cyclonic vorticity. This presented a more favorable environment for the formation of MCV-type PV anomalies and smaller, surface-based, meso-?-scale vortices. Although these vortices eventually merged to form a more concentrated vortex with stronger surface pressure gradients, the merger happened well after landfall of Allison and no strengthening ensued. The unstable, vorticity-rich environment was also favorable for the development of even smaller, meso-?-scale vortices that accompanied deep convective cells within one of Allison?s meso-?-scale vortices. The observations herein suggest that the meso-?- scale convective cells and vortices are the respective source of PV production and building blocks for the meso-?-scale vortices. Finally, this thesis discusses issues related to the multiple vortex nature of tropical cyclone formation. For instance, the tracking of developing tropical cyclones is greatly complicated by the presence of multiple vortices. For these cases, the paradigm of a single cyclone center is inappropriate and alternative tracking methods are introduced.
Sippel, Jason Allen
Aircraft Observations of Sub-cloud Aerosol and Convective Cloud Physical Properties
This research focuses on aircraft observational studies of aerosol-cloud interactions in cumulus clouds. The data were collected in the summer of 2004, the spring of 2007 and the mid-winter and spring of 2008 in Texas, central Saudi Arabia and Istanbul, Turkey, respectively. A set of 24 pairs of sub-cloud aerosol and cloud penetration data are analyzed. Measurements of fine and coarse mode aerosol concentrations from 3 different instruments were combined and fitted with lognormal distributions. The fit parameters of the lognormal distributions are compared with cloud droplet effective radii retrieved from 260 cloud penetrations. Cloud condensation nuclei (CCN) measurements for a subset of 10 cases from the Istanbul region are compared with concentrations predicted from aerosol size distributions. Ammonium sulfate was assumed to represent the soluble component of aerosol with dry sizes smaller than 0.5 mm and sodium chloride for aerosol larger than 0.5 mm. The measured CCN spectrum was used to estimate the soluble fraction. The correlations of the measured CCN concentration with the predicted CCN concentration were strong (R2 > 0.89) for supersaturations of 0.2, 0.3 and 0.6%. The measured concentrations were typically consistent with an aerosol having a soluble fraction between roughly 0.5 and 1.0, suggesting a contribution of sulfate or some other similarly soluble inorganic compound. The predicted CCN were found to vary by +or-3.7% when the soluble fraction was varied by 0.1. Cumulative aerosol concentrations at cutoff dry diameters of 1.1, 0.1 and 0.06 mm were found to be correlated with cloud condensation nuclei concentrations but not with maximum cloud base droplet concentrations. It is also shown that in some cases the predominant mechanisms involved in the formation of precipitation were altered and modified by the aerosol properties. This study suggests that CCN-forced variations in cloud droplet number concentration can change the effective radius profile and the type of precipitation hydrometeors. These differences may have a major impact on the global hydrological cycle and energy budget.
Axisa, Duncan
ARM tropical pacific experiment (ATPEX): Role of cloud, water vapor and convection feedbacks in the coupled ocean/atmosphere system. Progress report, September 1, 1991--August 31, 1992
Fitting Dynamic Models to the Geosat Sea Level Observations in the Tropical Pacific Ocean. Part II: A Linear, Wind-driven Model
The Geosat altimeter sea level observations in the tropical Pacific Ocean are used to evaluate the Performance of a linear wind-driven equatorial wave model. The question posed is the extent to which such a model can describe the observed sea ...
Lee-Lueng Fu; Ichiro Fukumori; Robert N. Miller
Characteristics of Strong Updrafts in Precipitation Systems over the Central Tropical Pacific Ocean and in the Amazon
Airborne in situ measurements of updrafts in tropical convective storms were analyzed to determine the similarities and differences between updrafts in a tropical continental and a tropical oceanic region. Two hundred fifteen updraft cores from ...
Nicholas F. Anderson; Cedric A. Grainger; Jeffrey L. Stith
Detecting Source Regions of Wave Activities in the Tropical Atmosphere by Applying Beamforming to Interpolated Data Grids
Wave activities are primary sources of weather disturbances and cyclones in the tropical atmosphere. One such activity is the intraseasonal variations in wind, convection, and precipitation in the tropical Indian and western tropical Pacific ...
Qi Hu; Zhaoning Liang; Michael W. Hoffman
The Role of Clouds, Water Vapor, Circulation, and Boundary Layer Structure in the Sensitivity of the Tropical Climate
The physical mechanisms that affect the tropical sea surface temperature (SST) are investigated using a two-box equilibrium model of the Tropics. One box represents the convecting, warm SST, high humidity region of the Tropics, and the other box ...
Kristin Larson; Dennis L. Hartmann; Stephen A. Klein
5, 1102911054, 2005 Convective gravity
ACPD 5, 1102911054, 2005 Convective gravity waves at mid-latitudes Y. G. Choi et al. Title Page Discussions Wind-profiler observations of gravity waves produced by convection at mid-latitudes Y. G. Choi111054, 2005 Convective gravity waves at mid-latitudes Y. G. Choi et al. Title Page Abstract Introduction
Paris-Sud XI, Université de
Comparison of Methods to Determine Tropical Tropopause Layer Cirrus Formation Mechanisms
A new method of estimating Tropical Tropopause Layer Cirrus (TTLC) formation mechanism (object method) is compared to interpretations of formation from previous studies using back trajectory calculations matched to convection identified from satellites and statistical relationships of TTLC with temperature and water vapor. The object method groups neighboring Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) TTLC cloud profiles into cloud objects and classifies them as convective (35% of TTLC) if they are directly attached to a convective cloud along the CALIPSO track. The percentage of back trajectory calculations that intersect convection (39-95% of TTLC within 5 days) depends strongly on the spatial and temporal resolution of the convection data set, and the manner in which deep convection is identified. Using minimum brightness temperature in 3 hourly, 1{sup o} resolution grid boxes to define convection, 46% of non-convective TTLC (37% of all TTLC) did not trace back to convection within 24 h. Back trajectory calculations of thin cirrus identified by the High Resolution Dynamics Limb Sounder (HIRDLS) gave similar results. Temperature is not a good proxy for formation mechanism as convective and non-convective TTLC frequencies both increase monotonically with decreasing temperature at approximately the same rate. Non-convective TTLC frequencies have a stronger relationship with relative humidity than convective TTLC frequencies, though are not sufficiently different to distinguish object method categories. A decrease in TTL cirrus frequency found at low temperatures in previous studies is caused by insufficient variability in reanalysis temperature data and is not indicative of TTLC formation mechanism.
Riihimaki, Laura D.; McFarlane, Sally A.; Liang, Calvin; Massie, Steven T.; Beagley, Nathaniel; Toth, Travis D.
Observational Analysis of Sudden Tropical Cyclone Track Changes in the Vicinity of the East China Sea
An observational analysis of observed sudden typhoon track changes is conducted with a focus on the underlying mechanism and the possible role of slowly varying low-frequency flows. Four typhoons that took a generally northwestward track prior to ...
Impacts of Initial Estimate and Observation Availability on Convective-Scale Data Assimilation with an Ensemble Kalman Filter
The ensemble Kalman filter (EnKF) uses an ensemble of short-range forecasts to estimate the flow-dependent background error covariances required in data assimilation. The feasibility of the EnKF for convective-scale data assimilation has been ...
F. Zhang; Chris Snyder; Juanzhen Sun
Aircraft Microwave Observations and Simulations of Deep Convection from 18 to 183 GHz. Part II: Model Results
In Part II of the 29 June 1986 case study, a radiative transfer model is used to simulate the aircraft multichannel microwave brightness temperatures presented in Part I and to study the convective storm structure. Ground-based radar data are ...
Hwa-Young M. Yeh; N. Prasad; Robert A. Mack; Robert F. Adler
Adjoint Sensitivity and Predictability of Tropical Cyclogenesis
The sensitivity of tropical cyclogenesis and subsequent intensification is explored by applying small perturbations to the initial state in the presence of organized mesoscale convection and synoptic-scale forcing using the adjoint and tangent ...
James D. Doyle; Carolyn A. Reynolds; Clark Amerault; Jonathan Moskaitis
Rapid Filamentation Zones in Intense Tropical Cyclones
Intense tropical cyclones often possess relatively little convection around their cores. In radar composites, this surrounding region is usually echo-free or contains light stratiform precipitation. While subsidence is typically quite pronounced ...
Christopher M. Rozoff; Wayne H. Schubert; Brian D. McNoldy; James P. Kossin
A Numerical Investigation of Tropical Island Thunderstorms
A version of the United Kingdom Meteorological Office mesoscale weather prediction model is used to simulate cases of deep tropical convection from the Island Thunderstorm Experiment off the north coast of Australia. Selected cases contrast ...
B. W. Golding
Inertial Instability and Mesoscale Convective Systems. part II. Symmetric CISK in a Baroclinic Flow
Numerous budget studies of organized persistent systems of convective clouds outside the tropics suggest that circulations of mesoscale proportions are important in supplying moisture to the convective clouds, though the dynamical nature of ...
Kerry A. Emanuel
Convective Forcing Fluctuations in a Cloud-Resolving Model: Relevance to the Stochastic Parameterization Problem
Idealized cloud-resolving model (CRM) simulations spanning a large part of the tropical atmosphere are used to evaluate the extent to which deterministic convective parameterizations fail to capture the statistical fluctuations in deep-convective ...
G. J. Shutts; T. N. Palmer
Observations of the Evolution of the Nocturnal and Convective Boundary Layers and the Structure of Open-Celled Convection on 14 June 2002
The Boundary Layer Evolution (BLE) missions of the International H2O Project (IHOP_2002) were designed to provide comprehensive observations of the distribution of water vapor in the quiescent boundary layer and its evolution during the early ...
Lindsay J. Bennett; Tammy M. Weckwerth; Alan M. Blyth; Bart Geerts; Qun Miao; Yvette P. Richardson
Hindcast/Forecast of ENSO Events Based upon the Redistribution of Observed and Model Heat Content in the Western Tropical Pacific, 1964�86
The redistribution of observed upper-ocean heat content in the western tropical North Pacific for the four-year period 1979�82 was shown by Pazan et al. to provide a qualitative hindcast capability for the 1982�83 ENSO event. A related study (...
Warren B. White; Stephen E. Pazan; Masamichi Inoue
An Observing System Simulation Experiment for an Optimal Moored Instrument Array in the Tropical Indian Ocean
In this paper, a series of observing system simulation experiments (OSSEs) are used to study the design of a proposed array of instrumented moorings in the Indian Ocean (IO) outlined by the IO panel of the Climate Variability and Predictability (...
Joaquim Ballabrera-Poy; Eric Hackert; Raghu Murtugudde; Antonio J. Busalacchi
Observations of a Tropical Thunderstorm Using a Vertically Pointing, Dual-Frequency, Collinear Beam Doppler Radar
This paper describes an investigation of a thunderstorm that occurred in the summer of 1991 over the National Astronomy and Ionosphere Center in Arecibo, Puerto Rico. Observations were made using collinear dual-wavelength Doppler radars, which ...
P. B. Chilson; C. W. Ulbrich; M. F. Larsen; P. Perillat; J. E. Keener
Characteristics of the Atmospheric Boundary Layer over a Tropical Station as Evidenced by Tethered Balloon Observations
A tethersonde observational program was conducted for eight days during February and March 1989 at Pune (18�32?N, 73�51?E, 559 m MSL), India, during daytime for the study of mixed-layer evolution. A surface- based nocturnal inversion of intensity ...
K. G. Vernekar; Brij Mohan; Sangeeta Saxena; M. N. Patil
Observations of the 40�50-Day Tropical Oscillation�A Review
Observational aspects of the 40�50-day oscillation are reviewed. The oscillation is the result of large-scale circulation cells oriented in the equatorial plane that move eastward from at least the Indian Ocean to the central Pacific. Anomalies ...
Roland A. Madden; Paul R. Julian
Mean winds observed with Indian MST radar over tropical mesosphere and comparison with various techniques
Abstract. Temporal variation of mean winds between the 65 to 85 km height region from the data collected over the course of approximately four years (1995�99), using the Indian MST radar located at Gadanki (13.5 ? N, 79.2 ? E), India is presented in this paper. Mesospheric mean winds and their seasonal variation in the horizontal and vertical components are presented in detail. Westward flows during each of the equinoxes and eastward flows during the solstices are observed in the zonal component. The features of the semiannual oscillation (SAO) and the quasi-biennial oscillation (QBO) in the zonal component are noted. In the meridional component, contours reveal a northward motion during the winter and a southward motion during the summer. Large inter-annual variability is found in the vertical component with magnitudes of the order of �2 ms ?1. The MST observed winds are also compared with the winds observed by the MF radar located at Tirunelveli (8.7 ? N, 77.8 ? E), India, the High Resolution Doppler Imager (HRDI) onboard the Upper Atmospheric Research Satellite (UARS), and with the CIRA-86 model. A very good agreement is found between both the ground-based instruments (MST radar and MF radar) in the zonal component and there are few discrepancies in the meridional component. UARS/HRDI observed winds usually have larger magnitudes than the ground-based mean winds. Comparison of the MST derived winds with the CIRA-86 model in the zonal component shows that during the spring equinox and the summer, the winds agree fairly well, but there are a lot of discrepancies in the other seasons and the observed winds with the MST radar are less in magnitude, though the direction is same. The strengths and limitations in estimating reliable mesospheric mean winds using
M. Venkat Ratnam; D. Narayana Rao; T. Narayana Rao; S. Thulasiraman; J. B. Nee; S. Gurubaran; R. Rajaram
Shallow and Deep Latent Heating Modes over Tropical Oceans Observed with TRMM PR Spectral Latent Heating Data
Three-dimensional distributions of the apparent heat source (Q1) ? radiative heating (QR) estimated from Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) utilizing the spectral latent heating (SLH) algorithm are analyzed. Mass-...
Yukari N. Takayabu; Shoichi Shige; Wei-Kuo Tao; Nagio Hirota
Observed Nonlinearities of Monthly Teleconnections between Tropical Pacific Sea Surface Temperature Anomalies and Central and Eastern North American Precipitation
Most investigations of relationships between tropical Pacific sea surface temperature anomaly (SSTA) events and regional climate patterns have assumed the teleconnections to be linear, whereby the climate patterns associated with cold SSTA events ...
David L. Montroy; Michael B. Richman; Peter J. Lamb
A Tropical Squall Line Observed during the COPT 81 Experiment in West Africa. Part II: Water Budget
The relative contributions of the different processes involved in the water budget of the 22 June 1981 tropical squall line are investigated. The kinematic and thermodynamic fields derived from Doppler radar data are used to calculate the sources ...
Michel Chong; Daniele Hauser
Observational Analysis of Tropical Cyclogenesis in the Western North Pacific. Part I: Structural Evolution of Cloud Clusters
This paper is the first of a two-part series summarizing recent attempts to advance omit understanding of the physical processes associated with tropical cyclone formation in the western North Pacific. A combination of rawinsonde composite and ...
Observing Long-Period Fluctuations of Surface Winds in the Tropical Pacific: Initial Results from Island Data
The utility of studying low-frequency surface weather phenomena with long time series of meteorological data from tropical Pacific islands is demonstrated. The wind stress changes associated with El Ni�o events in the period 1950�78 are examined ...
D. S. Luther; D. E. Harrison
Multiyear Observations of the Tropical Atlantic Atmosphere: Multidisciplinary Applications of the NOAA Aerosols and Ocean Science Expeditions
This paper gives an overview of a unique set of ship-based atmospheric data acquired over the tropical Atlantic Ocean during boreal spring and summer as part of ongoing National Oceanic and Atmospheric Administration (NOAA) Aerosols and Ocean Science ...
Nicholas R. Nalli; Everette Joseph; Vernon R. Morris; Christopher D. Barnet; Walter W. Wolf; Daniel Wolfe; Peter J. Minnett; Malgorzata Szczodrak; Miguel A. Izaguirre; Rick Lumpkin; Hua Xie; Alexander Smirnov; Thomas S. King; Jennifer Wei
A Comparison of VHF Wind Profiler Observations and the NCEP�NCAR Reanalysis over the Tropical Pacific
VHF wind profiler measurements of zonal and meridional winds are compared with the NCEP�NCAR reanalysis at sites in the tropical Pacific. By December 1999 the profilers at Darwin, Australia, and Biak, Indonesia, in the western Pacific; Christmas ...
Robert Schafer; Susan K. Avery; Kenneth S. Gage
Structure of Oceanic and Atmospheric Low-Frequency Variability over the Tropical Pacific and Indian Oceans. Part I: COADS Observations
The recurrent modes of combined oceanic and atmospheric low-frequency variability over the tropical Pacific and Indian oceans are calculated to provide quantitatively and structurally well-defined targets for simulation/prediction studies of ...
Sumant Nigam; Horng-Syi Shen
Nocturnal Continental Low-Level Stratus over Tropical West Africa: Observations and Possible Mechanisms Controlling Its Onset
Some spatiotemporal characteristics and possible mechanisms controlling the onset of the widespread, low-level nocturnal stratiform clouds that formed during May�October 2006 over southern tropical West Africa are investigated using cloudiness ...
Jon M. Schrage; Andreas H. Fink
Inclusion of Mesoscale Updrafts and Downdrafts in Computations of Vertical Fluxes by Ensembles of Tropical Clouds
Ensembles of convective clouds, especially in the tropics, often have widespread precipitating anvils associated with their deeper convective clouds. Mesoscale downdrafts occur below the middle-level bases of the anvils, and mesoscale updrafts ...
Robert A. Houze Jr.; Chee-Pong Cheng
Necessary Conditions for Tropical Cyclone Rapid Intensification as Derived from 11 Years of TRMM Data
Rainfall and convective properties of tropical cyclones (TCs) are statistically quantified for different TC intensity change categories by using Tropical Rainfall Measuring Mission (TRMM) data from December 1997 to December 2008. Four 24-h future ...
Haiyan Jiang; Ellen M. Ramirez
Radiative Forcing of a Tropical Direct Circulation by Soil Dust Aerosols
The effect of soil dust aerosols upon the tropical climate is estimated by forcing a simple model of a tropical direct circulation. The model consists of a region vertically mixed by deep convection and a nonconvecting region, for which budgets ...
R. L. Miller; I. Tegen
Intraseasonal Oscillations in the Global Atmosphere. Part I: Northern Hemisphere and Tropics
We have examined systematically oscillatory modes in the Northern Hemisphere and in the tropics. The 700 mb heights were used to analyze extratropical oscillations, and the outgoing longwave radiation to study tropical oscillations in convection. ...
Michael Ghil; Kingtse Mo
Tropical Warm Pool International Cloud Experiment (TWP-ICE): Cloud and Rain Characteristics in the Australian Monsoon
The impact of oceanic convection on its environment and the relationship between the characteristics of the convection and the resulting cirrus characteristics is still not understood. An intense airborne measurement campaign combined with an extensive network of ground-based observations is being planned for the region near Darwin, Northern Australia, during January-February, 2006, to address these questions. The Tropical Warm Pool � International Cloud Experiment (TWP-ICE) will be the first field program in the tropics that attempts to describe the evolution of tropical convection, including the large scale heat, moisture, and momentum budgets, while at the same time obtaining detailed observations of cloud properties and the impact of the clouds on the environment. The emphasis will be on cirrus for the cloud properties component of the experiment. Cirrus clouds are ubiquitous in the tropics and have a large impact on their environment but the properties of these clouds are poorly understood. A crucial product from this experiment will be a dataset suitable to provide the forcing and testing required by cloud-resolving models and parameterizations in global climate models. This dataset will provide the necessary link between cloud properties and the models that are attempting to simulate them. The experiment is a collaboration between the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Program, the Bureau of Meteorology (BoM), the National Aeronautics and Space Administration (NASA), the European Commission DG RTD-1.2, and several United States, Australian, Canadian, and European Universities. This experiment will be undertaken over a 4-week period in early 2006. January and February corresponds to the wet phase of the Australia monsoon. This season has been selected because, despite Darwin�s coastal location, the convection that occurs over and near Darwin at this time is largely of maritime origin with a large fetch over water. Based on previous experiments, the convection appears typical of maritime convection with widespread convection that has complex organization, but is not as deep or as intense as continental or coastal convection. Therefore, it is expected that the convection and cloud characteristics will be representative of conditions typical for wide areas of the tropics.
PT May; C Jakob; JH Mather
Mesoscale Convective Vortices in Multiscale, Idealized Simulations: Dependence on Background State, Interdependency with Moist Baroclinic Cyclones, and Comparison with BAMEX Observations
A set of multiscale, nested, idealized numerical simulations of mesoscale convective systems (MCSs) and mesoscale convective vortices (MCVs) was conducted. The purpose of these simulations was to investigate the dependence of MCV development and ...
Robert J. Conzemius; Michael T. Montgomery
Analysis of Convective Transport and Parameter Sensitivity in a Single Column Version of the Goddard Earth Observation System, Version 5, General Circulation Model
Convection strongly influences the distribution of atmospheric trace gases. General circulation models (GCMs) use convective mass fluxes calculated by parameterizations to transport gases, but the results are difficult to compare with trace gas ...
L. E. Ott; J. Bacmeister; S. Pawson; K. Pickering; G. Stenchikov; M. Suarez; H. Huntrieser; M. Loewenstein; J. Lopez; I. Xueref-Remy
Diabatic Divergence Profiles in Western Pacific Mesoscale Convective Systems
Heating in the atmosphere can be expressed as diabatic divergence ?d, which is nearly equal to the actual horizontal divergence ? in tropical convection. High-quality ? profile measurements from airborne Doppler radar �purls� in ten mesoscale ...
Brian E. Mapes; Robert A. Houze Jr.
Overview of the Convection and Moisture Experiment (CAMEX)
This paper presents an overview of the Convection and Moisture Experiment (CAMEX), including the field operations, aircraft platforms and missions, instrumentation, and data acquired during 1998 and 2001 field campaigns. A total of eight tropical ...
Ramesh Kakar; Michael Goodman; Robbie Hood; Anthony Guillory
Convection-Evaporation Feedback in the Equatorial pacific
The coupling between convection and surface evaporation is investigated to assess the importance of evaporative cooling in regulating the tropical sea surface temperature. It is found that such a coupling is scale dependent. On timescales of ...
Guang Jun Zhang; V. Ramanathan; Michael J. McPhaden
Humidity-temperature relationships in the tropical troposphere
Based on the observed interannual variations of water vapor and temperature over the past 26 years the authors have examined the relationship between the variations of water vapor and temperature in the tropical troposphere. In both the lower and upper troposphere, tropical mean specific humidity increases with temperature. The rate of fractional increase of specific humidity with temperature at 500 mb is as large as that in the surface boundary layer. However, the rate of fractional increase of specific humidity with temperature is significantly smaller than that given by a model with a fixed relative humidity, particularly in the region immediately above the tropical convective boundary layer. The variations of tropical mean relative humidity show consistently a negative correlation with the temperature variations. The authors have further compared the spatial structure of the specific humidity variations with that of the temperature variations. Though the vertical structure of tropical mean specific humidity has more variability than that of the tropical mean temperature, the leading EOF for the normalized specific humidity variations is almost exactly the same as the leading EOF for the normalized temperature variations. The characteristic horizontal structure of the specific humidity variations at levels in the free troposphere, however, is very different from that of the temperature variations. The leading EOF for the normalized specific humidty variations at levels in the free troposphere is characterized by regions with alternating positive and negative signs, while the leading EOF for the corresponding temperature variations has a single sign throughout the Tropics. When the variations are averaged zonally, the leading EOF for the normalized specific humidity variations still differs significantly from that of the normalized temperature variations, but the leading EOF has the same sign from the deep Tropics to the subtropics. 31 refs., 15 figs., 1 tab.
Sun, D.Z. [Princeton Univ., NJ (United States); Oort, A.H. [NOAA, Princeton, NJ (United States)
TWP-ICE Global Atmospheric Model Intercomparison: Convection Responsiveness and Resolution Impact
Results are presented from an intercomparison of global atmospheric model (GAM) simulations of tropical convection during the Tropical Warm Pool-International Cloud Experiment (TWP-ICE). The distinct cloud properties, precipitation, radiation, and vertical diabatic heating profiles associated with three different monsoon regimes (wet, dry, and break) from available observations are used to evaluate 9 GAM forecasts initialized daily from realistic global analyses. All models well captured the evolution of large-scale circulation and the thermodynamic fields, but cloud properties differed substantially among models. For example, liquid water path and ice water path differed by up to two orders of magnitude. Compared with the relatively well simulated top-heavy heating structures during the wet and break period, most models had difficulty in depicting the bottom-heavy heating profiles associated with cumulus congestus. The best performing models during this period were the ones whose convection scheme was most responsive to the free tropospheric humidity. Compared with the large impact of cloud and convective parameterizations on model cloud and precipitation characteristics, resolution has relatively minor impact on simulated cloud properties. However, one feature that was influence by the resolution study in several models was the diurnal cycle of precipitation. Peaking at a different time from convective precipitation, large-scale precipitation generally increases in high resolution forecasts and modulates the total precipitation diurnal cycle. Overall, the study emphasizes the importance of more environmental responsive convective parameterizations to capture various types of convection and the substantial diversity among large-scale cloud and precipitation schemes in current GAMs. This experiment has also demonstrated itself to be a very useful testbed for those developing cloud and convection schemes in these models.
Lin, Yanluan; Donner, Leo J.; Petch, Jon C.; Bechtold, P.; Boyle, James; Klein, Stephen A.; Komori, T.; Wapler, K.; Willett, M.; Xie, X.; Zhao, M.; Xie, Shaocheng; McFarlane, Sally A.; Schumacher, Courtney
Characteristics of Summer Convective Systems Initiated over the Tibetan Plateau. Part I: Origin, Track, Development, and Precipitation
Summer convective systems (CSs) initiated over the Tibetan Plateau identified by the International Satellite Cloud Climatology Project (ISCCP) deep convection database and associated Tropical Rainfall Measuring Mission (TRMM) precipitation for ...
Li Yaodong; Wang Yun; Song Yang; Hu Liang; Gao Shouting; Rong Fu
The Transformation of Tropical Storm Agnes into an Extratropical Cyclone. Part I: The Observed Fields and Vertical Motion Computations
This is the first of two papers dealing with the transformation of tropical storm Agnes (June 1972) into an extratropical cyclone. Synoptic analyses and vertical motion patterns are used to describe the behavior of Agnes over a five-day period ...
Geoffrey J. DiMego; Lance F. Bosart
Simulation of microphysical structure associated with tropical cloud clusters using mesoscale model and comparison with TRMM observations
An attempt has been made in the present study to examine the microphysical structure of a non-squall Tropical Cloud Cluster (TCC). Three-dimensional model simulations of cloud microphysical structure associated with a non-squall TCC occurred on 26 October ...
S. Abhilash; K. Mohankumar; S. Das
Airborne Doppler Observations of the Inner-Core Structural Differences between Intensifying and Steady-State Tropical Cyclones
Differences in the inner-core structure of intensifying [IN; intensity increase of at least 20 kt (24 h)?1, where 1 kt = 0.51 m s?1] and steady-state [SS; intensity remaining between �10 kt (24 h)?1] tropical cyclones (TCs) are examined using ...
Robert Rogers; Paul Reasor; Sylvie Lorsolo
Tropical Cyclone Kinematic Structure Retrieved from Single-Doppler Radar Observations. Part II: The GBVTD-Simplex Center Finding Algorithm
This paper is the second of a series and focuses on developing an algorithm to objectively identify tropical cyclone (TC) vorticity centers using single-Doppler radar data. The first paper dealt with the formulation of a single-Doppler radar TC ...
Wen-Chau Lee; Frank D. Marks Jr.
The Retrieval of Asymmetric Tropical Cyclone Structures Using Doppler Radar Simulations and Observations with the Extended GBVTD Technique
The ground-based velocity track display (GBVTD) technique is extended to two Doppler radars to retrieve the structure of a tropical cyclone�s (TC�s) circulation. With this extension, it is found that the asymmetric part of the TC radial wind ...
Yu-Chieng Liou; Tai-Chi Chen Wang; Wen-Chau Lee; Ya-Ju Chang
Application of the 85 GHz ice scattering signature to a global study of mesoscale convective systems
It has long been observed that tropical convection tends to cluster, organizing into multicellular mesoscale convective systems (MCS), In convective towers, updrafts on the order of 10 m s-I favor the formation of large, precipitation-sized ice, which strongly scatters upwelling 85 GHz radiation. The 85 GHz brightness temperature is related to the amount of ice in an MCS and, indirectly, to the strength of the updrafts producing the ice. This study used an objective technique to identify MCSs from the Special Sensor Microwave/Imager's 85 GHz channel to describe the size, intensity, and geographic distribution of MCSs between 35'N and 35'S for January, April, July, and October 1993. An MCS was defined as an area at least 2000 km 2 of 85 GHz polarization corrected brightness temperatures 1 0 5 @) MCSS. Over the oceans, median brightness temperature depression was 20-30 K below 225 K, while over land, it was 35-45 K below 225 K. Tropical Africa had the coldest median minimum brightness temperature. The sub-tropical oceans had the warmest median minimum brightness temperatures. MCSs were 35% more frequent over the oceans at sunrise than at sunset, and 60% more frequent over tropical continents at sunset than at sunrise. Both continental and oceanic MCSs tended to be larger at sunrise than at sunset. Continental MCSs tended to be colder at sunset than at sunrise, but oceanic MCSs tended to be marginally colder at sunrise than at sunset. In general, continental MCSs appeared to be smaller and more intense than oceanic MCSS, and the largest and the most intense MCSs occurred more frequently in the sub-tropics.
Devlin, Karen Irene
Global-scale observations of changes in ionospheric echo occurrence and convection during periods of increased solar wind activity and increased geomagnetic activity .
??This thesis presents an investigation of ionospheric plasma convection and HF radar echoes during periods of enhanced geomagnetic activity. The work was split into two� (more)
Gillies, Deborah
Convective Inhibition as a Predictor of Convection during AVE-SESAME II
The AVE-SESAME 11 data set of 19 April 1979 is examined to determine the thermodynamic conditions prior to the onset of deep convection in western Kansas. The observations indicate that the convective region was characterized locally by ...
Frank P. Colby Jr.
Transient Response to Localized Episodic Heating in the Tropics. Part I: Excitation and Short-Time Near-Field Behavior
The dynamical response to localized, unsteady tropical heating is studied in a stochastic framework. Spectral statistics of the random wave response are derived from those of tropical convection using the primitive equations for a spherical ...
Murry L. Salby; Rolando R. Garcia
Momentum Flux by Lines of Cumulonimbus over the Tropical Oceans
Examination of aircraft and rawinsonde data gathered in nine tropical mesoscale convective line cases indicates that all but two lines systematically increased front-to-rear momentum at heights greater than about 4 km, and rear-to-front momentum ...
Margaret A. LeMone; Gary M. Barnes; Edward J. Zipser
Origin of Lapse Rate Changes in the Upper Tropical Troposphere
Vertical motions in clouds arise from a variety of thermodynamic processes, including latent heat release, evaporative cooling, melting, and cloud radiative heating. In the Tropics, the net upward vertical mass flux from convective systems should ...
Ian Folkins
An Extended Model for the Potential Intensity of Tropical Cyclones
Emanuel�s theory of hurricane potential intensity (E-PI) makes use of the assumption that slantwise convective instability vanishes in a steady-state vortex of a tropical cyclone. In the framework of an extended mathematical potential intensity ...
Thomas Frisius; Daria Sch�nemann
Control of the Tropical Tropopause and Vertical Transport across It
A 3D primitive equation model is used to investigate how the tropical tropopause is influenced by cumulus convection in the troposphere and mean upwelling in the stratosphere. The model simulates the residual mean circulation explicitly, whereas ...
Murry Salby; Patrick Callaghan
Effects of Environmental Flow upon Tropical Cyclone Structure
Numerical simulations of tropical-cyclone-like vortices are performed to analyze the effects of unidirectional vertical wind shear and translational flow upon the organization of convection within a hurricane�s core region and upon the intensity ...
William M. Frank; Elizabeth A. Ritchie
A Low-Level Circulation in the Tropics
Deep convective tropical systems are strongly convergent in the midtroposphere. Horizontal wind measurements from a variety of rawinsonde arrays in the equatorial Pacific and Caribbean are used to calculate the mean dynamical divergence profiles ...
Ian Folkins; S. Fueglistaler; G. Lesins; T. Mitovski
Distribution of Helicity, CAPE, and Shear in Tropical Cyclones
The previous study of helicity, CAPE, and shear in Hurricane Bonnie (1998) was extended to all eight tropical cyclones sampled by NASA during the Convection and Moisture Experiments (CAMEX). Storms were categorized as having large or small ...
John Molinari; David Vollaro
An Analysis of the Conditional Instability of the Tropical Atmosphere
The ice phase is included in thermodynamic calculations of convective available potential energy (CAPE) for a large number of soundings in the tropical atmosphere, at both land and ocean stations. It is found that the positive-buoyancy ...
Erle Williams; Nilton Renno
The Relationship of Highly Reflective Clouds to Tropical Climate Anomalies
The interannual variability of tropical convection related to the Southern Oscillation (SO) and regional climate anomalies is studied from satellite-derived estimates of highly reflective clouds (HRC) during 1971�87. The novel HRC data bank ...
Stefan Hastenrath
Entropy Sources in Equilibrium Conditions over a Tropical Ocean
Confusion has existed as to sources of entropy due to irreversible processes in the atmosphere, the total of which matches the export of entropy by radiation. What is the mechanical efficiency of convection? For an ideal tropical oceanic system ...
Charles Warner
Dual-Polarization observations of Microbursts Associated with Intense Convection: The 20 July Storm during the MIST Project
A detailed case study of the microbrust-producing storm on 20 July 1986 during the MIST Project is presented, together with visual (based on cloud photogrammetry) and radar observations during the life cycle of the storm. In particular, ...
Roger M. Wakimoto; V. N. Bringi
Convection towers
DOE Patents (OSTI)
Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water. 6 figs.
Prueitt, M.L.
Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.
Prueitt, Melvin L. (Los Alamos, NM)
Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode.
Obtaining Best Estimates for the Microphysical and Radiative Properties of Tropical Ice Clouds from TWP-ICE In Situ Microphysical Observations
Best estimates of the bulk microphysical and radiative properties (ice water content, visible extinction, effective radius, and total concentration) are derived for three case studies of tropical ice clouds sampled during the Tropical Warm Pool ...
A. Protat; G. M. McFarquhar; J. Um; J. Delano�
Geothermal: Sponsored by OSTI -- Improving Convection Parameterization...
Office of Scientific and Technical Information (OSTI)
Improving Convection Parameterization Using ARM Observations and NCAR Community Atmosphere Model Geothermal Technologies Legacy Collection HelpFAQ | Site Map | Contact Us | Admin...
Tropical Oceanic Hot Towers: Need They Be Undilute to Transport Energy from the Boundary Layer to the Upper Troposphere Effectively? An Answer Based on Trajectory Analysis of a Simulation of a TOGA COARE Convective System
This paper addresses questions resulting from the authors� earlier simulation of the 9 February 1993 Tropical Ocean Global Atmosphere Coupled Ocean�Atmosphere Research Experiment (TOGA COARE) squall line, which used updraft trajectories to ...
Alexandre O. Fierro; Edward J. Zipser; Margaret A. LeMone; Jerry M. Straka; Joanne (Malkus) Simpson
Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode. 5 figures.
Four-Dimensional Assimilation of Multitime Wind Profiles over a Single Station and Numerical Simulation of a Mesoscale Convective System Observed during IHOP_2002
This study examines the impact of assimilating multitime wind profiles over a single station on the numerical simulation of a warm season mesoscale convective system over the region from the Kansas and Oklahoma border to the Texas Panhandle, ...
Lei Zhang; Zhaoxia Pu
Heat distribution by natural convection
DOE Green Energy (OSTI)
Natural convection between spaces in a building can play a major role in energy transfer. Two situations are investigated: convection through a single doorway into a remote room, and a convective loop in a two-story house with a south sunspace where a north stairway serves as the return path. A doorway-sizing equation is given for the single-door case. Detailed data are given from the monitoring of airflow in one two-story house and summary data are given for five others. Observations on the nature of the airflow and design guidelines are presented.
Balcomb, J.D.; Yamaguchi, K.
The Convective System Area Expansion over Amazonia and Its Relationships with Convective System Life Duration and High-Level Wind Divergence
The relationships between the initial area expansion rate of tropical convective systems and their total life duration are analyzed during the period of the Wet Season Amazon Mesoscale Campaign/Large-Scale Biosphere�Atmosphere (WETAMC/LBA) ...
Luiz Augusto T. Machado; Henri Laurent
Tropical-Extratropical Interactions of Intraseasonal Oscillations
Tropical-extratropical interactions of intraseasonal oscillations (ISOs), based on 30 yr (1979-2009) of northern winter observations and theory, are compared. The phase relationships between the tropical signal of the leading theoretical ISO for a ...
Jorgen S. Frederiksen; Hai Lin
Maintenance of the free-tropospheric tropical water vapor distribution. Part I: Clear regime budget
The water vapor budget, of the free troposphere of the maritime Tropics is investigated using radiosonde observations, analyzed fields, and satellite observations, with particular attention paid to regions free of organized convection. In these arid regions, time-average drying by subsidence must be balanced by moistening horizontal advection from convective areas and via vertical turbulent transport from below. It is found that for at least 25% of the maritime Tropics, 80% - 10% of this source above 700 mb is by horizontal advection. The remainder comes from vertical convective transport (scales < 250 km), with a pronounced local maximum at 500 mb. The regions for which this is true are characterized by pentad outgoing longwave radiation > 270 W m{sup -2} and may be said to exist out of equilibrium with the surface as regards moisture. Transport from below makes a significant contribution between 700 and 800 mb, despite the usual presence of an inversion below these levels, but is difficult to quantify accurately. The convective transport convergence is estimated as a residual from large-scale budgets and directly from sounding time series by an independent method, which shows a narrow maximum at 500 mb. Half of the paper addresses the question of data accuracy, including sounding and analyzed data, as it pertains to the question at hand. It is concluded that the moisture budgets from the European Centre for Medium-Range Weather Forecasts (ECMWF) analyses are of useful accuracy despite some significant mean discrepancies between the analyses and sounding observations in convective areas. The budget is found to be similar to that of a general circulation model based on the ECMWF forecasting model. Humidity measurements from operational soundings appear responsive below 300 mb, but then abruptly become unresponsive. 39 refs., 15 figs., 1 tab.
Sherwood, S.C. [Univ. of California, La Jolla, CA (United States)
An homogeneous nuclear power reactor utilizing convection circulation of the liquid fuel is proposed. The reactor has an internal heat exchanger looated in the same pressure vessel as the critical assembly, thereby eliminating necessity for handling the hot liquid fuel outside the reactor pressure vessel during normal operation. The liquid fuel used in this reactor eliminates the necessity for extensive radiolytic gas rocombination apparatus, and the reactor is resiliently pressurized and, without any movable mechanical apparatus, automatically regulates itself to the condition of criticality during moderate variations in temperature snd pressure and shuts itself down as the pressure exceeds a predetermined safe operating value.
Hammond, R.P.; King, L.D.P.
Observations of temperature, wind, cirrus, and trace gases in the tropical tropopause transition layer during the MJO
Satellite observations of temperature, optically thin cirrus clouds, and trace gases derived from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC), Cloud-Aerosol Lidar and Infrared Pathfinder Satellite ...
Katrina S. Virts; John M. Wallace
LIRAD Observations of Tropical Cirrus Clouds in MCTEX. Part II: Optical Properties and Base Cooling in Dissipating Storm Anvil Clouds
During the Maritime Continent Thunderstorm Experiment (MCTEX), several decaying storm anvils were observed. The anvil clouds exhibited typical patterns of fallout and decay over a number of hours of observation. The anvil bases were initially ...
C. M. R. Platt; R. T. Austin; S. A. Young; A. J. Heymsfield
Radiative Forcing of Simulated Tropical Cloud Clusters
A number of field experiments and subsequent studies in the 1970s and 1980s have led to the belief that radiative processes play a more significant role in the evolution of tropical mesoscale convective systems (MCSS) than was once thought. In ...
Rosemary Auld Miller; William M. Frank
Rapid Intensification of a Sheared Tropical Storm
A weak tropical storm (Gabrielle in 2001) experienced a 22-hPa pressure fall in less than 3 h in the presence of 13 m s?1 ambient vertical wind shear. A convective cell developed downshear left of the center and moved cyclonically and inward to ...
Convective Transport Theory for Surface Fluxes Tested over the Western Pacific Warm Pool
Turbulent flux measurements from five flights of the National Center for Atmospheric Research Electra aircraft during the Tropical Oceans and Global Atmosphere Coupled Ocean�Atmosphere Response Experiment (TOGA COARE) are used to test convective ...
Lawrence Greischar; Roland Stull
Possibility of the Visible-Channel Calibration Using Deep Convective Clouds Overshooting the TTL
The authors examined the possible use of deep convective clouds (DCCs), defined as clouds that overshoot the tropical tropopause layer (TTL), for the calibration of satellite measurements at solar channels. DCCs are identified in terms of the ...
B-J. Sohn; Seung-Hee Ham; Ping Yang
Effects of Tropospheric Wind Shear on the Spectrum of Convectively Generated Gravity Waves
The authors examine the effects of tropospheric wind shear on the phase speed spectrum of gravity waves generated by tropical convection. A two-dimensional cloud-resolving model is used to perform numerous squall line simulations with the ...
Jadwiga H. Beres; M. Joan Alexander; James R. Holton
Role of Gravity Waves in Triggering Deep Convection during TOGA COARE
The role of gravity waves in the initiation of convection over oceanic regions during the Tropical Ocean Global Atmosphere Coupled Ocean�Atmosphere Response Experiment (TOGA COARE) experiment is investigated. First, an autocorrelation method is ...
C. Lac; J-P. Lafore; J-L. Redelsperger
Convective Forcing in the Intertropical Convergence Zone of the Eastern Pacific
One of the goals of the East Pacific Investigation of Climate, year 2001 process study (EPIC2001), was to understand the mechanisms controlling the forcing of deep atmospheric convection over the tropical eastern Pacific. An intensive study was ...
David J. Raymond; G. B. Raga; Christopher S. Bretherton; John Molinari; Carlos L�pez-Carrillo; �eljka Fuchs
Global Variability of Mesoscale Convective System Anvil Structure from A-Train Satellite Data
Mesoscale convective systems (MCSs) in the tropics produce extensive anvil clouds, which significantly affect the transfer of radiation. This study develops an objective method to identify MCSs and their anvils by combining data from three A-...
Mesoscale Convective Systems over Western Equatorial Africa and Their Relationship to Large-Scale Circulation
This study examines mesoscale convective systems (MCSs) over western equatorial Africa using data from the Tropical Rainfall Measuring Mission (TRMM) satellite. This region experiences some of the world�s most intense thunderstorms and highest ...
Brian Jackson; Sharon E. Nicholson; Douglas Klotter
Vertical Motion Structure in Maritime continent mesoscale Convective Systems: Results from a 50-MHz Profiler
Wind profiler data wore used to determine the vertical motion structure in four tropical mcsoscale convective systems (MCSs), which occurred during the Down Under Doppler and Electricity Experiment (DUNDEE) near Darwin. Northern Territory, ...
Robert Cifelli; Steven A. Rutledge
Relating Passive 37-GHz Scattering to Radar Profiles in Strong Convection
Tropical Rainfall Measuring Mission (TRMM) Microwave Imager and precipitation radar measurements are examined for strong convective systems. Storms having similar values of minimum 37-GHz polarization-corrected temperature (PCT) are grouped ...
Daniel J. Cecil
Intraseasonal and Seasonal-to-Interannual Indian Ocean Convection and Hemispheric Teleconnections
Deep tropical convection over the Indian Ocean leads to intense diabatic heating, a main driver of the climate system. The Northern Hemisphere circulation and precipitation associated with intraseasonal and seasonal-to-interannual components of ...
Andrew Hoell; Mathew Barlow; Roop Saini
CAPE and Convective Events in the Southwest during the North American Monsoon
The relationship between atmospheric stability, measured as CAPE, and deep precipitating convection has been widely studied but is not definitive. In the maritime tropics, CAPE and precipitation are usually inversely correlated. In continental ...
David K. Adams; Enio P. Souza