Ocean level rising, or the floor getting higher?

In a geologically static world you might have a point. Erosion would wear down the land surface, depositing the sediment in the ocean - where 'Archimedes principle' would apply, and seas level would rise by displacement. There are two main reasons why this doesn't account for the rate of sea level rise that we are seeing: plate tectonics and observed rates.

The Earth is a tremendously dynamic environment in which plate tectonics drive an approximate balance between crustal destruction by erosion and subduction, as against freshly generated land at 'constructive margins'. This 'wobbly balance' has been going  for the past 3+ billion years, and is likely to continue for several billion years more. The balance of rise and fall in sea level averages close to zero but has positive and negative anomalies over time. In all cases, fluctuations are slow - in the order of millions of years (excluding the much larger short-term fluctuations caused by ice ages). So for all practical purposes the base-line is 'zero change', upon which is superimposed the effects of sea level rise as we exit the last ice age, i.e. the last 12000 years and continuing. On top of that is the recent effect of human-induced climate change. Let us consider these  rates compared to the hypothetical rate of erosion and sea level rise in a static world.

During the 20th century, sea level rise was estimated from tide-gauges, which raises the problem of 'are we measuring rising sea or sinking land?'  For the last decade or so we have been able to measure absolute mean sea levels by satellite. That is, independent of land levels. Now we can re-evaluate old data, and come up with 'real' average rates of rising sea level. They turn out to be about 2.5 +/- 1.5 mm/year for most of the last century. Now they have accelerated to more than twice that amount. See, for example:

https://www.climate.gov/news-features/understanding-climate/climate-change-global-sea-level

This is the global average, and yes, there are all manner of positive and negative anomalies. Now consider sediment displacement. Measuring the global sediment flux from rivers to oceans is extraordinarily difficult, for reasons which would take several pages to explain. But of the diverse range of estimates the consensus seems to be between 20 and 60 Gtonnes per year for the world's major rivers. Leaning towards the upper bound, and adding in a factor for the minor rivers, and assuming an average sediment density of about 2.5, we arrive at about 40 billion cubic metres of sediment entering the oceans each year. There are about 360 million square kilometres of ocean, so on average, the annual increase in ocean sediment is about 1.1 mm. In reality, this is an upper bound with the a more realistic estimate being about 0.6 mm. So, even without taking oceanic subduction into account, the observed sea level is at least an order of magnitude more than can be accounted for by sediment displacement. Or to answer your question, no, the ocean floor isn't rising at any rate that we can measure. Conversely, sea level is rising at a rate that is consistent with thermal expansion of the ocean surface, combined with nett global ice melt.


It is a myth. To say that it is unscientific is perhaps not the best phrasing, but Groundhog day isn't the most accurate prognostication method around. For something to be scientific, it needs to follow the scientific method. Given that Groundhog day follows the myth that:

A groundhog that sees it's shadow will become frightened, seeking shelter from the upcoming chill of 6 more weeks of winter, or
A groundhog that doesn't see it's shadow is certain that a chill is not on its way

, the implication derived from a poem being that nice weather now means bad weather later and vice-versa. Without defining 'winter' or 'spring' I question the testability of the hypothesis. In reality, astronomical spring occurs 6 weeks and 4 days after Groundhog day, making the distinction between the groundhog's "definition" of spring entirely subjective. But translating a subjective metric into an objective criteria, it is less accurate than the Farmer's Almanac of 50%.
If you want a more likely explanation on why a groundhog might behave the way it does, one need not look much farther than a picture from Punxsutawney, PA on groundhog day:

Given such a crowd, will an animal react more about the crowd or the upcoming weather? My guess is that if you saw such a crazed crowd show up to your house at 7:25 AM, you would want to crawl into a hole too. A groundhog must go into it's hole at some point, and I don't know of a part of the myth that says that the groundhog must immediately go back into its hole. Doing a groundhog day tradition with so much festivity, scientifically (not necessarily rationally though), be a contaminating factor to any sort of experiment. That is, even slight deviations in how such a thing is conducted (and given that groundhogs like Phil basically live like royalty in comparison to groundhogs in their natural state) make any rigorous evaluation of Phil's prognostication ability questionable.


Why does air subside in the Eye - the lowest pressure area of a tropical cyclone?

I will just talk about an already formed tropical cyclone. Converging winds spiral in (counterclockwise in northern hemisphere) over the warm ocean waters towards the central low pressure area of the eye.

At the eye they spiral upwards, taking the warm, moist ocean air high into the atmosphere. As it reaches cooler elevation, the air releases its latent heat, adding more energy to the storm.

So you have a tremendous volume of air converging from 360 degrees around the hundreds of miles of the storm, all converging on the eye and spiraling up with an intense updraft, creating a very low pressure near the surface in the eye/core.

High above the eye wall this upflow begins to spread out. This permits cool dry air above the eye to sink down into the central core of the eye (that is why the eye is often clear and cloud free).

So why is the hurricane core/eye low pressure when there is cool dry air subsiding down into the core/eye?

Soundings taken within the eye show a low-level layer (at surface) that is relatively moist with an inversion above, i.e., it appears that the sinking cool dry air (which warms somewhat as it is compressed in descent) never reaches the ocean surface, but only reaches within 1 - 3 km (1 - 2 mi) of the surface. See, among other sources, http://www.aoml.noaa.gov/hrd/tcfaq/A11.html.


What is the total mass of organic carbon on Earth?

You could never have an estimate which was anything more than a wild guess masquerading as an estimate. To estimate the carbon in living vegetable matter alone would be hard enough, and result in a very inaccurate approximation, but to include the quantity in the Earth's crust as well could only be a wild and very inaccurate guess. The exact quantity of all the Earth's oil reserves, coal, peat, limestone and other carbonates isn't known with any precision, then there are oil shales,tar sands, asphalt lakes,clathrates and God knows what else,but the great thing about a sufficiently large, wild guess is that no one could ever prove you wrong, especially as on a few occasions and by sheer chance, guesses turn out to be right!  But it is an estimate, presumably an accurate one that you asked for, and that is impossible.


How do scientists measure the age of old animal remains?

Organic material (plants and animals) contains carbon.

Carbon has three main isotopes: carbon 12, 13 and 14. Carbon 14 is radioactive, with a half life of 5730 years.

Carbon 14 is continuously created in the atmosphere by cosmic rays hitting nitrogen. The nitrogen atoms lose a proton when struck by cosmic rays, turning the affected nitrogen atom into an atom of carbon.

The carbon 14 then reacts with oxygen in the atmosphere to create carbon dioxide. Plants taken in the radioactive carbon dioxide along with non radioactive carbon dioxide. Plant eating animals take in the radioactive carbon when they eat plants and meat eating animals take in radioactive carbon when they eat other animals.

When a plant or animal dies it stops exchanging carbon with the environment and it dies with a certain amount of radioactive carbon 14.

By measuring how much carbon 14 is contained in a specimen and knowing the half life of carbon 14, scientists can calculate when an animal died.

Due to the half life of carbon 14 being 5730 years, carbon 14 dating can only reliably be used for dates up to 50 000 years old.

More details about carbon 14 dating can be found here.


Please help me identify these two rocks?

The photos are pretty bad but a couple of things still stand out, the translucent sample shows apparent conchoidal fracture which coupled with the colour and level of transparency makes me think it's green Obsidian. Obsidian is a volcanic glass and can be mistaken for manmade glass, what is sold as obsidian in many stores is in fact not a natural substance at all. Also as I should have pointed out originally without some scale and clarity the sample presented may well be a broken piece of manmade glass.

The second photo is a little clearer, the apparent fine layering and particular shade of green looks just like a sample of fused volcanic ash I have that came from Mount Tongariro.


How would this experiment's different particle types produce atmospheric reflectivity?

foreword: Particles and Droplets

Commonly, atmospheric particles can be considered as wet particles. E.g. when we talk about sulfate particles ($SO_4^{2-}$), these particles are actually droplets with dissolved sulfuric acid (or with a dissolved sulfate-cation compound).

Mechanism involving $SO_2$

$SO_2$ is released as gas and it reacts to $SO_4^{2-}$ (sulfate). Basically, there are different reaction pathways for the formation of sulfate from $SO_2$:

$SO_{2,g}$ --(gas phase reaction)--> $H_2SO_{4,g}$ --($H_2O$ accumulates)--> "sulfate particle"
$SO_{2,(g)}$ --(goes into solution)--> $SO_{2,solution}$ --(formation)--> $H_2SO_{4,solution}$ (deprotonizes directly)

Commonly, the second pathway is dominant. The relevant aspect is that it leads to the formation of ultra fine sulfate particles (sulfate droplets).

Sulfate particles are cloud condensation nuclei. That means that they support the formation of clouds. There are satellite pictures available, in which you can identify shipping lanes by lines of clouds. These clouds were formed because ships emit large amounts of $SO_2$ (at least outside of sulfur emission control areas).

Most clouds above the ocean reflect more solar radiation than the sea surface. In general, clouds above the ocean are considered as "good clouds" with respect to cooling the Earth. Since a large proportion of the Earth is covered by sea surface, one might wonder to generate clouds above it - e.g. by releasing $SO_2$. However, as far as I know, this process is relevant in the troposphere.

Releasing $SO_2$ into the stratosphere (as proposed in the linked article) is not meant to support cloud formation (correct me, if I am wrong). Nevertheless, the released $SO_2$ leads to ultra-fine sulfate particles. These sulfate particles themselves effectively scatter solar radiation and, thus, prevent it from reaching the Earth's surface. There is also a Wikipedia article available here.

Unfortunately, sulfate indirectly degrades the ozone layer: sulfate leads to the release of radicals that (and their successors) catalytically destroy ozone. See Keith et al. (2016) for a more detailed overview.

Why $CaCO_3$?

The basic idea is to add salts of alkali metals that neutralize sulfuric acid and nitric acid (generated in the presence of sulfuric acid) when we emit $SO_2$. This will reduce the negative impact on the ozone layer. $CaCO_3$ is such a salt (Keith et al., 2016).

Why $Al_2O_3$?

Foreword: I am not expert on this and just read some articles on this topic.

According to Weisenstein et al. (2015), fine aluminum particles (as well as diamonds) are an alternative to sulfate particles. According to them, aluminum is favourable. However, as studies on emissions from missiles and space crafts indicate, $Al_2O_3$ also has negative impacts on the ozone layer (SomeReport; DoD, 2004): $Cl$ radicals are released that degrade ozone. $CaCO_3$ also counteracts here, too.


What are these radial line patterns shown in representations of antarctica?

I can't be sure, but I strongly suspect that the radial lines in the first two images are the result of a bug in the software used to draw the map, probably resulting from vector polygons that are described in an inappropriate coordinate system going around, or too close to, the south pole.

It's impossible to guess at the meaning of the blue lines in the third image without any caption or context, but from referring back to your link for the article that you took it from, my guess would be that the lines show the tracks of the flights that gathered the data.

No, they are not related to each other.


Is it possible to forecast ocean salinity 100 years into the future?

The answer to the main question is that we are capable of forecasting salinity 100 years into the future. The more relevant question might be how well are we currently forecasting salinity. First, lets look at what we know about how salinity is currently changing.

Global salinity is the result of the balance between surface freshwater flux (evaporation minus precipitation), terrestrial runoff and mixing and advective processes in the ocean. The changes in salinity are intrinsically connected to alterations in the global hydrological cycle and are expected to be a consequence of climate change (Held and Soden, 2006). A general change has been identified with surface subtropical areas becoming saltier and high-latitude regions becoming fresher (Antonov et al., 2002; Boyer et al., 2005). Durack and Wijffels (2010) found salinity increases in regions dominated by evaporation while freshening occurred in precipitation-dominated regions. They suggested the change was a consequence of an intensification of the global hydrological cycle. These results are the basis for the conclusions in the IPCC 2013 report (TFE.1 Figure 1).

The global climate models that are used to evaluate future climate scenarios are calibrated to reproduce the past ocean and atmospheric conditions, which includes trying to match the described salinity trend. They likely constitute the best source of future global salinity estimates. Their ocean salinity forecast is based on the estimation of the global hydrological cycle evolution, especially evaporation, precipitation, river discharge and ocean mixing.

With regard to the quality of the salinity estimates, there is probably a large uncertainty associated with those fields. There is going to be substantial improvement in the quality of the salinity forecast because of the recent availability of better global salinity products. The remote data obtained from satellites (SMOS and Aquarius) have been providing a much better global view of salinity changes. Also, the ARGO profilers are expanding our understanding of the ocean interior.

In terms of evaluating uncertainty, I like the approach of Meier et al., 2006 looking at multi-model ensemble estimates. They combined down-scaled regional models with global simulations under several scenarios and provided several metrics for salinity uncertainties. The relationship between forecast errors and forecast horizons is quite complex and in fact represents an entire field of study. There is a lot of information in the IPCC 2013 report dealing with prediction quality, ensemble generation and size, and forecast quality assessment (for instance Chapter 11).

 Source: Aretxabaleta et al. (2017)

Using a little bit of self-promotion, I can also say that estimating what the current salinity trend from observations is a tough problem. In this recently  published article, we show that the changes in trend are spatially complex and changing in time. We argue that, as mentioned before, the changes in salinity field give a good representation of the long-term changes in the global hydrological cycle.


Impact craters vs volcanic explosions on Mars

In addition to Gordons approach it might be possible to differentiate between impact and volcanic craters by comparing the characteristics of the ejecta [1]. The apparent thermal inertia (defined for example in [2]) seems to be higher around volcanic craters [3]. Unfortunately the linked papers about the method are conference abstracts about ongoing research and I did not find a paper where they try to apply the method to remote sensing data from mars.

[1] Peet, V. M., M. S. Ramsey, and D. A. Crown. "Comparison of Terrestrial Morphology, Ejecta, and Sediment Transport of Small Craters: Volcanic and Impact Analogs to Mars." 36th Annual Lunar and Planetary Science Conference. Vol. 36. 2005.

[2] Putzig, Nathaniel E., and Michael T. Mellon. "Apparent thermal inertia and the surface heterogeneity of Mars." Icarus 191.1 (2007): 68-94.

[3] Peet, V. M., M. S. Ramsey, and D. A. Crown. "Remote Sensing Analyses of Small Terrestrial Volcanic and Impact Craters: A Mars Analog for Formation, Morphology, and Erosional Processes." Lunar and Planetary Science Conference. Vol. 38. 2007.


Paper result validation and the scientific method in earth science

Let's start with the trivially true: programming is not earth science; earth science is not programming. Programming is one tool of many in earth science. In programming, the end result is the program itself. In earth science, that's never the case: but one end result is algorithms developed that inform us about the real world, and implemented in a progam.

What if there is a bug in a peer-reviewed paper? Well, of course there is, just as there are bugs in pretty much every program that does anything useful in the real world. So what?

Validating source code is  the domain of programming. Validating algorithms and observations is the domain of earth science. Re-running someone else's code with the same input data is barely any kind of validation at all, and rarely the interesting kind. Taking someone else's algorithms and implementing them yourself, that's the sort of validation I see across the physical, life, social sciences.

So I don't see someone else's source code? No big deal. Indeed, that's often a good thing: it means I can genuinely clean-room their algorithm.


Who are winners from the global warming? Are there any?

Global economic costs of natural disasters:

In the period 1998-2017, disaster-hit countries reported direct
economic losses of 2,908 billion dolars of which climate-related disasters
accounted for 2,245 billion dolars or 77% of the total.
This compares with total reported losses for the period 1978-1997 of 1,313 billion dolars of which climate-related disasters accounted for 895 billion dolars or 68%.
Source: undrr.org

The economic figures are frightening and climate change has been shown to increase these events all over the world. It is difficult to claim for specific countries winning anything at all with global warming after this introduction.
Your assumption "...Siberia may become more habitable." is proven false. Science find more extrem winters in East Asia and Europe after CC, even the average temperature raises and winters become shorter (emphasis mine):

Our simulations with the ECHAM5 general circulation model demonstrate that lower‐troposphere heating over the B‐K seas in the Eastern Arctic caused by the sea ice reduction may result in strong anticyclonic anomaly over the Polar Ocean and anomalous easterly advection over northern continents. This causes a continental‐scale winter cooling reaching −1.5°C, with more than 3 times increased probability of cold winter extremes over large areas including Europe. Our results imply that several recent severe winters do not conflict the global warming picture but rather supplement it.
Source: A link between reduced Barents‐Kara sea ice and cold winter extremes over northern continents", Climate and Dynamics, cited in Expect more extreme winters thanks to Global Warming, say scientists, Independent.

It could be debated the global beneficts of the opening of sea routes if the Arctic melts, but the costs all over the globe would exced the beneficts if we arrive to that scenario (economic looses due to floods in coastal cities among others).
At a regional and local scale some industries may benefict from CC:

Places where summer heat atract new tourists.
New agricultural products adapted to heat.
....

But the costs for the region again far outweigh the benefits.
In the first case the region will encounter problems as desertification, availability of water, biodiversity loss, ....
The second case imply the ruling agriculturists loose their crops; as an example imagine what Bordeaux can win planting oranges instead of his known red wine despite some opportunistic individual may do fortune with it (...).


Does anyone know a book/article/research that talks about forest fire prevention?

This book is based on Australian experience, some of it may be relevant of North American wildfires. I read it ten years ago.

Paul Collins, Burn - The Epic Story of Bushfire in Australia, Allen & Unwin, 2006, ISBN 9781741750539, ISBN 1 74175 053 9.

Part 4, titled: The Great Fire Debates, has three chapters (9 to 11);

 09 To burn or not to burn
 10 Fire thugs
 11 Fireproofing Australia.

Contact for Allen & Unwin:

83 Alexander Street
CROWS NEST NSW 2065
Australia

Telephone: + 61 2 8425 0100
Fax: +  61 2 9906 2218
Email: info@allenandunwin.com
Web: [www.allenandunwin.com][1]

Another book you may want to try is:

Stephen J. Pyne, Burning Bush - A Fire History of Australia, University of Washington Press, Seattle & London, 1998.

Also published by Henry Holt & Company, New York, 1991

As part of his "Cycle of Fire" suite of books, the same author has written books, titled:

Vestal Fire: An Environmental History, Told through Fire, of Europe and Europe's Encounter with the World
Fire in America: A Cultural History of Wildland and Rural Fire
World Fire: The Culture of Fire on Earth

The CSIRO (Commonwealth Scientific & Industry Research Organisation) in Australia, used to have two departments that researched bushfires/wildfires:

CSIRO Division of Forest Research Library
CSIRO National Bushfire Research Unit

Stephen J. Pyne mentions them in his book. You might be able to get access to the results of research carried out by the CSIRO.

Just be mindful of the different terminologies used in different countries to describe the same thing: bushfires in Australia and wildfires in North America.


Why are most effects of the predicted climate change negative?

I would say that the reason is because human civilisation, and particularly agricultural practices, evolved and are adapted to the pre-industrial climate.  This means that any substantial change in the climate will require changes in our civilisation and agriculture, which inevitably has a cost.  So the reason that most of the changes are negative is not to do with the science, but to do with us.


I am not too much into the subject, but it is a curious phenomenon indeed.
There is a recent publication in Scientific Reports (Enomoto et al., 2017) where a group of scientists performed some lab experiments and reported:

  CO2 gases passing through the newly created fracture surface of the rock were electrified to generate pressure-impressed current/electric dipoles, which could induce a magnetic field following Biot-Savart’s law, decrease the atmospheric electric field and generate dielectric-barrier discharge lightning affected by the coupling effect between the seismic and meteorological activities

If you want to read the full paper you can search it with this reference:

Enomoto, Y., Yamabe, T., & Okumura, N. (2017). Causal mechanisms of seismo-EM phenomena during the 1965–1967 Matsushiro earthquake swarm. Scientific Reports, 7. doi: 10.1038/srep44774.

It is open access.


Using acoustics to measure the composition, density, and hardness of layers

The answer to your question is 'yes': you can probe a medium of arbitrary complexity using sound waves, and relate the propagating wave to the physical properties encountered on its path: the stiffness (Hooke's law), density (Newton's law), and you can locate the layers by figuring out where the stiffness and density change. If the competition only requires you to submit a hypothetical method, such a seismological method certainly fits the bill.

Unfortunately, when it comes to practically implementing such a method; I advice against it. You'll find too many obstacles on your path that require expert input and money. For example:

You require a very well controlled source: you need to know exactly the source function (the wavelet) that ends up in your medium; which is distorted by the actuator's frequency response, and which is distorted by the usually weak coupling between your source and the medium.
You require a high-resolution receiver as well, to record the signal that propagated within the medium, which is similarly not trivial to create.
After you have solved these (difficult!) problems, you have to turn your recording at the surface into a quantitative 2-D/3-D physical model of the Earth, i.e. a model that tells you the velocity of the medium and the thickness of each layer. This requires extensive data-processing and typically requires many numerical wave simulations; only then, when your numerical simulation predicts data that resembles the data that you recorded, you may assume that you may have found the approximate physical state of the medium. This technique is called Full-Waveform Inversion, and is the only one I'm aware of that will provide the answer to all your questions.

The problems in the last point are due to the fact that surface recordings provide a massively underdetermined problem. Say, as an example that you drop a weight onto the medium, and then it takes 100ms before you hear the first echo come from the medium. Then you infer that the wave traveled back and forth to depth with a certain velocity. This gives an equation: $100\ \text{ms} \approx \frac{2h}{V}$ that doesn't reveal what the depth $h$ actually is or what the velocity $V$ actually is! The problem is thus poorly constrained by the data, and you require a lot of data to get a good understanding of the subsurface. Then, furthermore, your waves propagate in an elastic medium which excites many types of waves: compressional waves, shear waves, surface waves, $\dots$,  which all travel at different speeds and are sensitive to different physical properties. You require some good data-processing to isolate only the wave that you are interested in!

As said in the comments, the size of the medium is no limitation, you simply scale up the wave's frequencies to the ultra-sound region! It is generally thought that you can locate objects in the Earths subsurface when they are separated by a distance $d\geq\lambda/2$, where $\lambda=\frac{V}{f}$ is the wavelength, with $V$ the velocity of the medium and $f$ the wave's frequency. The average speed of a compressional wave in rocks is about 5km/s, thus you require a frequency of at least $f=\frac{5\,000\ \text{m/s}}{2d\ \text{m}}$ to find your object of size $d$. If you resolution requires separation up to 1cm, you require a wave with a frequency of at least 80 $\text{kHz}$: well into the ultra-sound territory!

I'm sorry to give such a demotivating answer, but seismology is simply too complex to be a viable project for anything but a fully-fledged multi-year commercial or PhD project. My suggestion would be to build a variation to a Cone Penetration Test, which measures the resistance to pushing a cone into the ground (which is directly related to the hardness of the rock!) at a fixed speed. Whenever the resistance changes you are encountering a new layer, such that the size and number of layers is easily inferred. That would satisfy all the requirements, I think. Then again, I have no expertise with the Cone Penetration Test, and perhaps it is not as easy as I think...


Your uwnd variable holds 32 bit floats and has shape (1,73,144) corresponding to time, lat, lon and is located in the Dataset you have called 'U'.

One way to put this in a numpy array is:

uwind = np.zeros((lat,lon), np.float)
uwind = U.variables['uwnd'][1,:,:]

The first line sets the size of the uwind array, which is helpful from a performance standpoint and the second loads the data from time 1 into the array.  lat and lon above are your grid dimensions 73 and 144 and np is the numpy module.

The u wind is just the east-west component of the wind.  The north-south component will be in the v wind variable.  You will need both to plot the wind.  To plot the barbs you will need to setup arrays for your x and y coordinates which will depend on lat,lon and possibly your map projection.  once you have an x and y array as well as uwind and vwind you can plot the wind barbs using matplotlib as:

plt.barbs(x, y, u, v)

and can customize their look with various options. The plt reference is the matplotlib.pyplot module.

For further reading, here are some examples of plotting netcdf data from a friend of mine at CSU.


What do the researchers in Antarctica wear if they must go outside during winter?

The US Antarctica Program publishes information about the required extreme cold weather gear. It's provided by the government and has to be returned after your deployment ends. The list is here along with other information. Here's another document that discuses clothing. I've extracted the list below.

Jackets
1 each GOR-TEX® wind jacket
1 each Helly Hansen® rain jacket
1 each polar fleece jacket
1 each Carhartt® jacket optional
1 each Carhartt vest optional
1 each red down parka optional

Pants
1 each GOR-TEX bib coveralls for grantees only
1 each Helly Hansen rain pants
1 each polar fleece pants
1 each Carhartt bib coveralls optional
1 each Carhartt pants

Thermal
2 each thermal top
2 each thermal bottoms

Hat and Neck
1 each Balaklava
1 each neck gaiter
1 each polar fleece cap

Gloves
1 pair leather work gloves (unlined)
1 pair leather work gloves (insulated)
1 pair rubber gloves (with liners)
1 pair GOR-TEX mitts
1 pair polypropylene gloves
1 pair wool gloves

Footwear
2 pair tube socks
1 pair snow boots (Sorel™ or LaCrosse®)
1 each fisherman boots (rubber or steel-toed) optional

Miscellaneous
1 pair goggles
1 each duffle bag


How are Quaternary alluvial deposits differentiated in subglacial latitudes?

They seem to be differentiated according to their morphology, Qof deposits being highly dissected and more consolidated than Qyf, thus older. From a random pamphlet of the map series:

Qyf Alluvial fan deposits (Holocene)—Unconsolidated, heterogeneous layers of sand, silt, and gravel; relatively undissected; deposited by streams emanating from canyons onto alluvial plains; identified primarily by fan morphology and topographic expression. Internal contacts delineate individual alluvial fans
Qof Alluvial fan deposits (Pleistocene)—Discontinuous or highly dissected deposits of semiconsolidated, moderately to poorly sorted layers of silty clay, silt, sand, and gravel

The pamphlet also states that "unit ages [...] reflect local stratigraphic relations", so they are relative ages, not absolute dating.


Strata always mean a collection of layers. A single layer is called a stratum. The plural of stratum is strata.


How does the lapse rate in clouds compare with the lapse rate of air?

The lapse rate of temperature is ignorant of clouds, it only cares that either $e/e_s < 1$ (dry) or $e/e_s >= 1$ (moist), where $e$ is vapor pressure and $e_s$ is saturation vapor pressure.  A cloud is saturated (and in places supersaturated) and so the lapse rate will be the same as saturated air outside of a cloud.

The theoretical parcel at 100% humidity when subsequently lifted (in the presence of cloud condensation nuclei (CCN)) will itself experience nucleation and condensation and become a cloud.  In this respect there can be no difference between the saturated parcel outside of a cloud and a saturated parcel within a cloud, both will experience the same lapse rates.

With that said, some types of clouds will cause a difference.  Consider a parcel at its level of free convection (LFC) within a deep convective cloud and a parcel far from the cloud, saturated in clear air at the same height.

The parcel in clear air when lifted will cool at the moist lapse rate but entrain the surrounding dry air and the result will be less than moist adiabatic.  The entrainment will also limit the vertical extent of the parcels buoyancy.
The parcel in the deep cloud will be saturated in a moist environment and will rise and cool at the moist adiabatic rate.  As it is inside the cloud, we'll say entrainment is not important.  This parcel will also rise high enough for ice processes to become important and will experience additional warming due to the enthalpies of sublimation and fusion (latent heat released from vapor->solid and liquid->solid transitions).

In this perspective, the parcel in the cloud to have a different temperature profile than the out of cloud parcel.  This isn't because of any difference in the moist lapse rate between the parcels or even how the thermodynamics work out, but rather because of the dynamic effect of entrainment.

Another factor to consider are the radiative properties of clouds vs clear air.  Clouds will absorb terrestrial longwave radiation and warm, and the water vapor in humid air will do the same thing.  Also on the periphery of the cloud where entertainment and evaporation is taking place, there will be some cooling from the phase change.  I don't have back of the envelope estimates for either of these effects, and I feel they are probably tangential to the question asked if we limit consideration of the cloud parcel to a parcel well inside of a deep cloud.


How much energy is needed to alter the path of a hurricane?

This is not a complete answer, but offers insights to research of some perspectives of the question you raised.
There has been a document recently written about this, Controlling Hurricanes
Can hurricanes and other severe tropical
storms be moderated or deflected? (Hoffman, 2004). In it, there are several main considerations, one major consideration in relation to your questions is that studies show that changes in the energy available can potentially alter the path of a hurricane.  The studies reported in the article

confirms that these massive, chaotic systems are susceptible to
minor changes in their initial conditions—for instance, the air temperature and
humidity near the center of the storm and in the surrounding regions

Using computer simulations of hurricanes, they confirmed that

changes in
precipitation, evaporation and air temperature could alter a
storm’s path or weaken its winds.

Even though the article suggests one of your suggestions, about microwave heating of the air or the water, this power would be harnessed by satellite based solar panels, the main simulated methods appear not to be a case of adding the energy to the hurricane itself - but rather robbing the hurricane of its energy sources, examples include
Cloud seeding with silver iodide or similar material is suggested, these would promote precipitation, which would rob the eye wall of

the water it needs to grow and
intensify

Another method, and rather unique is the use of biodegradable oil on the water's surface, specifically

Biodegradable oil could be distributed across
the sea surface in the path of a hurricane
to limit evaporation—the source of a
storm’s energy

A study by Stanford University, reported in the article Offshore wind farms could tame hurricanes before they reach land, Stanford-led study says (Carey, 2014), suggest by computer modelling that

"We found that when wind turbines are present, they slow down the outer rotation winds of a hurricane," Jacobson said. "This feeds back to decrease wave height, which reduces movement of air toward the center of the hurricane, increasing the central pressure, which in turn slows the winds of the entire hurricane and dissipates it faster."

The data indicated that

In the computer model, by the time Hurricane Katrina reached land, its simulated wind speeds had decreased by 36-44 meters per second (between 80 and 98 mph) and the storm surge had decreased by up to 79 percent.
For Hurricane Sandy, the model projected a wind speed reduction by
35-39 meters per second (between 78 and 87 mph) and as much as 34
percent decrease in storm surge.

In terms of using a nuclear detonation to stop or divert a hurricane, the author of the article Can You Stop a Hurricane by Nuking It? (2012) describes the potential effectiveness of this method

might be about as effective as trying to stop a speeding Buick with a feather.

mainly due to as you said in your question:

the same amount of energy released by exploding a 10-megaton nuclear bomb every 20 minutes.

A nuke on water nearby may make the hurricane worse, by heating the water, thus 'feeding' the hurricane.


First of all the question is not appropriately titled. The polar vortex ALWAYS exists as explained in this URL - What is the Polar Vortex ?. The real question is whether a polar vortex split up at the poles and the smaller vortices moved equatorward or not. In February of 2018 the polar vortex did split high up in the atmosphere due to a SSW event.  If we take a look at it from GFS forecast data from the period - February 2nd 2018 10 hPa wind data and then a few days later - February 12th 2018 10 hPa wind data.

Content owned by The National Observatory of Athens, Greece confirms it in this youtube video - Polar Vortex split. An associate of mine who creates popular science videos for the larger public came up with a layperson's view of the polar vortex in this youtube video -SSW explanation plus polar vortex split

The key point in Simon Clark's video of the sudden warming of the stratosphere can be seen in GFS forecast data as well - Air temperature before polar vortex split at 10 hPa and this Air temperature after the polar vortex split
There is a 40 degree centigrade warming of the stratospheric air at 10 hPa over some locations. Over the temporal scale (3-4 days) that is fairly dramatic and that effect is eventually "felt" at the surface level. While the mechanism behind this is still a matter of deep research the impact is synoptic to planetary scale to cause a  cold wave through Europe as was asked in this question - Where did the daily temperature variation go?.

Finally I am not sure of the impact on US stations but I believe it affected Western Canada and Europe.

UPDATE
With NOAA partially restoring their database and their website the images are available now. I am displaying the 10 hPa air temperature for two different dates. One is before the SSW event (9th February 2018) and another one after the SSW event (13th February 2018). The stereographic projection is over the northern hemisphere

As one can make out over large areas of the North Pole the air temperature at the 10 hPa has increased by around 40-50 degree Kelvin and the colder air has been displaced equatorwards. Unlike the GFS forecast images shown earlier these temperature values are the mean values averaged over a single day and are therefore more representative than a single time associated with the GFS data.

Finally the vector wind at the 10 hPa levels on both those two days and you can see clearly the split vortices in this one

Looking at the literature for the polar vortex splits it appears that they also use the geopotential height increase over the poles to indicate the impact of a SSW.
The first image is prior to  a SSW which indicates the presence of a stable polar vortex(lowered geopotential height)

The second image is after a SSW and one that indicates the instability of the polar vortex(it's weakened state) and split vortices over Western Canada and Northern Europe. (Geopotential height increase over the poles).

Copyright Owner for NCAR NOAA images

NOAA NCAR URL


No. However, you can look at backprojection results which show where the energy is coming from. It gives you some idea about how the earthquake evolved in time, e.g., see here (click play to see the video).

The only other way to get what you want is to use observations from dense arrays. E.g., see here, but this is only possible in certain regions.

EDIT (answer to your comment below): Codes like SPECFEM3D are good for simulating low frequency ground motion (e.g., 0.1-1Hz). High frequency (1-10Hz) ground motion, that affects smaller structures like 1-2 story houses or even mid-rise buildings is very difficult to simulate (you need a very accurate, very high resolution, velocity model with the right soil/geotechnical layer etc., a highly accurate source model with the 'right' slip distribution, rise time, rupture velocity etc., and finally, a very large supercomputer). You're better off using GMPE's like USGS but that will not tell you how things evolve in time.

Bottomline is that statistics of high frequency ground motion are rather well understood (scales with distance) but not for lower frequencies where effects like rupture directivity/velocity, path/basin effect etc. become even more important.

Finally, Okada's elastostatic solutions are for calculating the final displacement field and doesn't have time component, i.e., you can simulate the final slip but not how it evolves with time which is an elastodynamic problem. Also, the final displacement field alone doesn't tell you anything about PGA/PGV.


How do we apply the Stefan-Boltzmann equation to radiative heat transfer from/to CO2 in the atmosphere?

We don't

Emissivity of CO$_2$

Your claim of low emissivity of CO$_2$ is not entirely true. First off, it matters what the wavelength of emission is when determining emissivity. Carbon dioxide has specific bands of high absorption (which correspond to high emissivity). These bands are crucial for climate modeling, so listing a numerical emissivity value without specifying the wavelength is not a useful measurement.

Secondly, emissivity of a gas isn't as simple as that of a solid surface because solid surfaces are more or less opaque to the IR radiation emitted in accordance with the Stefan-Boltzman equation. Therefore, the surface area of the 'blackbody' is what is important when calculation emission or absorption. For a gas, however, IR radiation will penetrate some distance through it.

The result is that you need to calculate emissivity of a gas as a function of its optical depth. Staley and Jurica, 1970 present calculations where they do that for carbon dioxide in the 15 $\mu$m absorption band (the most important one for climate models). Their results show that at 20 C, CO$_2$ has an emissivity of 0.0823 at an optical depth of 1 cm; 0.244 at an optical depth of 10 m; etc.

Spectrum matters

As I mentioned above, the emission spectra matters a lot. In the case of CO$_2$, there is a specific emission band which corresponds to the absorption band. This means that any radiation emitted by CO$_2$ is emitted at just the perfect wavelength to be reabsorbed by other molecules of CO$_2$.

CO$_2$ also differs from water vapor in that it remains dispersed through the atmosphere and doesn't coalesce into weather formations. Water vapor aggregates into clouds; the emissions from those clouds can be significant because there is much more water vapor emitting in a cloud than in the (drier) air above the cloud. CO$_2$ doesn't exhibit that behavior and thus its emissions are mostly trapped by other CO$_2$, whereas blackbody emission from cloud banks can be significant on the global scale.

What does get emitted to space and lost is heavily attenuated by the presence of other CO$_2$ molecules and is insignificant compared to emissions from the Earth's surface, which pass through the absorption band gaps in water vapor and CO$_2$.

Conclusion

I don't actually know what factors each specific climate model uses. There may be some that account for the emissivity of CO$_2$. It may be that all the models account for it; it has been over a decade since I contributed to those models. However, whether they account for it or not, it is not a significant factor in driving temperature changes the way the emissivity of the Earth's surface is.


Megathrust earthquakes on subduction zones

Megathrust is not a particularly well defined term but in my experience it generally refers to very large earthquakes that occur on the subduction interface.

The subduction interface is the main surface which separates the overriding plate from the subducting plate and is where most of the convergence is accomodated.

(image source)

Earthquakes occur on the subduction interface when the two plates are locked together (referred to as strong coupling) and cannot move past each other, leading to accumulation of strain which is eventually released in an earthquake. The amount of coupling on the subduction interface can vary strongly along its length. Chlieh et al., 2008 says this about the Sumatran megathrust:

  Near the equator, the megathrust is locked over a narrow width of only a few tens of kilometers. In contrast, the locked fault zone is up to about 175 km wide in areas where great interplate earthquakes have occurred in the past.

Some subduction interfaces are thought to be almost entirely decoupled and do not generate megathrust earthquakes but large earthquakes can still occur on splay faults in the accretionary prism (Shaw et al., 2008).

With regards to the second part of the question, earthquakes are seismic waves generated by rupturing of rocks in response to accumulated stress. Every earthquake creates a rupture patch with a certain area. The 2004 Sumatra earthquake had a rupture patch that was over 1300 km long which is enormous, hence why it had a such a large magnitude. The rupture started at the southern end of the fault and propagated northwards at 2-3 km/s, taking around 9 minutes to fully rupture. The epicentre is the location of the initial rupture.

The seismic moment of an earthquake ($\mathrm{M_0}$ is related to the area of the rupture patch ($\mathrm{A}$), the average displacement on the fault ($\mathrm{D}$) and the friction coefficient on the fault plane ($\mu$) by: $$\mathrm{M_0 = \mu A D}$$


What mechanism leads to these spectacular iridescent patterns in clouds labeled as a "Fire Rainbow"?

this looks like mother of pearl clouds https://en.wikipedia.org/wiki/Polar_stratospheric_cloud
they are made of ice crystals very high in the atmosphere the only clouds higher in the atmosphere are noctilucent clouds.if you google mother of pearl clouds there is a lot of pictures and information.
as a result of global warming the stratosphere is getting colder this makes
mother of pearl clouds or rainbow clouds visible from larger areas of our planet then before(more info is needed to dokument this statement of mine).

An other alternative is irradecent clouds,They have many of the same properties as mother of pearl clouds https://en.wikipedia.org/wiki/Cloud_iridescence

The last alternative is a pollen rainbow but they do often form in the direction of the sun or moon(it is a little hard to see if the sun is behind the clouds in your pictures)The colors of a pollen rainbow is often more vibrant than other types of optical phnomena https://soranews24.com/2019/03/09/high-pollen-levels-in-eastern-japan-create-pretty-rainbow-suns/


There are different senses of weight used within branches of physics and engineering. In the strictest physical sense "weight", is given by W = mg. i.e. weight is the force on an object due to gravity alone.  Clouds are not "weightless" in that sense, since they are not far enough away from the Earth to escape its gravitational pull.

The reason that clouds stay up in the sky is, as you say, because they are acted on by an equal and opposite force, namely the surrounding buoyancy of the air. Rain drops are formed by water molecules condensing around some sort of nucleus (a speck of dust, for example). This is triggered by the cooling of the cloud, or lifting to lower pressures, which reduces the moisture-carrying capacity of that particular "parcel" of air.

While the arrangement of water molecules in the cloud make it light enough to be buoyant in the air, the arrangement of those same molecules in rain drops are not – so they begin to fall.

By analogy, I would think of the fact that a ship is buoyant, despite its huge mass, but if you 'condensed' the ship into a lump of steel with the same mass, it would obviously sink. It's weight remains the same however, no mass has been removed, and the value of g has not changed. So to answer your second question, no, phase changes do not affect weight. (Although strictly speaking, in quantum physics it can do – but the amount is negligible here)

Gases which are "lighter than air" will eventually settle in a portion of the atmosphere where the surrounding gases are the same density. They are not weightless, nor do they have a negative weight. The molecules are still experiencing a force due to the Earth's gravity.


Start with the original equation. Let's first write the Hydrostatic equation:

$$\frac{\partial p}{\partial z}=-\rho g$$

So let's prove that $$-g=c_p\theta\frac{\partial \pi}{\partial z}$$

If we use the product rule, we observe $$-g=c_p(\frac{\partial \theta \pi}{\partial z}-\pi\frac{\partial \theta}{\partial z})$$

Since $\pi=\frac{T}{\theta}$, we can say that $T=\pi\theta$, which makes the above equation

$$-g=c_p(\frac{\partial T}{\partial z}-\pi\frac{\partial \theta}{\partial z})$$

It can be shown that
$$\frac{\partial \theta}{\partial z}=\frac{\theta}{T}(\frac{\partial T}{\partial z}+\frac{g}{c_p})$$

which can be rewritten as
$$\frac{\partial \theta}{\partial z}=\frac{1}{\pi}(\frac{\partial T}{\partial z}+\frac{g}{c_p})$$

Substituting this into my fourth equation
$$-g=c_p(\frac{\partial T}{\partial z}-\frac{\pi}{\pi}(\frac{\partial T}{\partial z}+\frac{g}{c_p}))$$

From here I think you can figure it out.

Derivation for $\frac{\partial \theta}{\partial z}$
$$\theta=T(\frac{p_0}{p})^\frac{R_d}{c_p}$$
$$log(\theta)=log(T)+\frac{R_d}{c_p}(log(p_0)-log(p))$$
$$ \frac{1}{\theta}\frac{\partial \theta}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}-\frac{R_d}{c_p P}\frac{\partial P}{\partial z}$$
Utilizing hydrostatic equation
$$ \frac{1}{\theta}\frac{\partial \theta}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}+\frac{R_d \rho g}{c_p P}$$
$$ \frac{1}{\theta}\frac{\partial \theta}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}+\frac{g}{c_p T}$$

$$ \frac{\partial \theta}{\partial z}=\frac{\theta}{T}(\frac{\partial T}{\partial z}+\frac{g}{c_p })$$


Yes, they have many impacts:

They provide a substrate for algae to grow and they can have whole ecosystems under them. You might think that such substrate is transient because it is melting, but Arctic and Antarctic waters are often below zero degrees Celsius, therefore, freshwater ice doesn't melt. You can find many articles about such ecosystems (here is one).
They transport sediments and nutrients into the ocean.
They provide safe rest areas for animals like seals, birds and penguins.
They impact the temperature of surface waters, specially in fjords.
They stir the sea floor in shallow waters

And there must be more ways they impact the environment and ecosystems but those are the ones I can think about right now.


Has the Earth had it's wobble that causes the seasonal variation in solar energy in the northern and southern hemispheres for it's entire history?

First it depends on how you define the "entire history" of the earth. There was a pre-earth that was hit by a Mars sized body. The collision fragments ultimately collapsed into the present earth and moon. Exactly how massive the pre-earth was and its orbital parameters are "unknown", meaning we know the parameters with much less precision than we know the parameters today.

Second there are two factors here. The seasonal (yearly variation) is caused mostly by the earth's axial tilt even though the distance between the earth and sun varies a bit since the earth's orbit is an ellipse rather than a circle. However the wobble of the earth is better better described as the precession of the earth's axis and it currently has a period of about 26,000 years.

  Is this variation evident in the geologic record or is it an open question?

There is evidence in geological record for season and precession changes for the present earth.

Isotopic composition of glacial ice and ocean sediments reflect yearly temperature variations. The yearly temperature changes also cause seasonal changes in the distribution of the earth's weight which effect the precession and tilt.

Lava cools leaving imprints of the instantaneous magnetic field of the earth over geological time. The interaction of the magnetic field drift and reversal, the precession of the earth, the axial tilt of the earth, and the plate movement of the earth is not well understood. It is basically governed by chaotic system interactions. For example plate movement can cause earthquakes which are as of yet unpredictable.

Again what the precession and tilt were like for the "pre-earth" is mostly a mystery.

  Could a meteor impact like that which killed the dinosaurs 66 million years ago have altered or created the wobble?

The impact that created the moon was with a Mars sized body and definitely effect the earth's precession and tilt.

  Are there any factors dampening or increasing the seasonal wobble over time?

Moon damps the tilt over geologic time. The instantaneous flow of the liquid magma inside the earth may increase or decrease the precession and/or tilt, but as the earth cools the overall effect is to decrease both.


Why do hurricanes hitting the US East Coast seem to go north once hitting land?

It is mostly due to the Coriolis effect (aka Coriolis Force). (Another reference here) Because of the Coriolis Effect, parcels of air (think of boxes of air) in the northern hemisphere are deflected to the right. This means that air around the subtropical ridge over the Atlantic ocean circulates clockwise.

Think of a tropical cyclone as a parcel, or box of air. It tries to complete the clockwise rotation around the subtropical high.

Now, inevitably someone will say 'Aha! I know of a storm that actually moved south.' Yes, different things can cause tropical cyclones to move in strange directions, such as the Fujiwhara Effect, other meteorological features. But by and large, the Coriolis force is the dominant cause of the curvature of the path of tropical cyclones.

It is also worth pointing out that the hurricane also has parcels of air inside of it. The Coriolis Force acts on that too, promoting rotation.


How do you calculate the elevation at which clouds will form (lifting condensation level)?

ANSWER:
$h={\Delta}t/{\Delta}l$
$h=$ height of LCL (unit depends on unit height of lapse rates)
${\Delta}t=T-T_d$
${\Delta}l=l_t-l_d$
$T$ is surface temp (deg)
$T_d$ is surface dewpoint temp (deg)
${\Delta}l=$ difference between lapse rates (deg)
$l_t=$ dry adiabatic lapse rate of temperature (deg/unit height)
$l_d=$ lapse rate of the saturation mixing ratio corresponding to the surface dewpoint (deg/unit height)


Soft Question: How Best to Thoroughly Exhaust the Literature

I would suggest combing Google Scholar with the following methods:

Search keywords just as you've mentioned.
When you hit on a semi-relevant paper, check the citations for relevant information.
Additionally check the collected works of the authors of said papers.
Search specifically for review papers or graduate-level textbooks for context on a subject and more citations.

The perk of interdisciplinary Earth Science is that everything connects.  The downside of interdisciplinary Earth Science is that information is dispersed.  Good luck.


Force is used to (try to) move objects apart. Energy is expended as the objects move and thereby separate. In a pure physics sense, until an object moves, absolutely no work energy is expended. You can push on a wall all you want with as much force as you want but, unless the wall moves, you do no work.

A stress-strain curve of a materials is a map of force to cause a deformation. The area under the curve is a map of the energy to cause the deformation. Up to the yield stress, the area is resilience. This is the energy expended to cause elastic deformation of the material. Because the stress strain curve is a straight line in the elastic region, the functional form of resilience $R$ is

$$R = \sigma_y \epsilon_y / 2 = \sigma_y^2 / 2E $$

where $\sigma_y$ is yield stress, $\epsilon_y$ is yield strain, and $E$ is Young's (elastic) modulus.

A further stress-strain function happens up to breaking. The total area under the stress-strain curve to break is toughness. The stress strain curve is not linear in this region. Integration methods are required.

The fissure forms because the material breaks, not because it reaches the end of its elastic deformation. The force needed is the obtained from the true breaking stress of the material. The energy required is obtained as the toughness of the material.

Ductile materials have a yield, a tensile, and a breaking stress. The tensile strength is the point where the material begins to neck. Think chewing gum stretched ... necking is where the gum thins.

Perfectly brittle materials have no yield. They just fail after elastic deformation. The toughness is the resilience in this case.

Many cases for materials that show only modest if any ductility and no necking assign the yield stress as the failure stress and ignore breaking stress. The toughness is greater than resilience, but the distinction is not a hard one.

Resilience and toughness may appear to have the same units as stress (e.g. Pa = N/m$^2$). In reality, a better unit designation for both is energy per unit volume (e.g. J/m$^3$).


Can a sonar used to graph the ocean floors detect through polluted and highly populated waters?

Using sonar to map the ocean floor is not usually affected by pollution or by the occasional fish, if it's a normal herring or cod sized fish. Plastic pollution usually floats or sinks so it isn't a problem. A fish the size of a basking shark would show up on the sonar, but it wouldn't be a problem. Large shoals of fish also show up, but it would have to be a very large shoal indeed to interfere with mapping the ocean floor. There are seasonal shoals large and continuous enough to do this, but only at certain times of the year in a very few locations where they are on migration in their billions. I have never heard of one causing problems for a vessel whose mission was to map the ocean floor or search for a sunken ship. Sonar is sometimes used by trawlers to search for shoals of fish.


Why aren't the Hawaiian islands a continuous strip of land?

Don't be mislead by the subaerial part, it is actually a ridge on a large scale but neither the lava production rate nor erosion rates are constants. That leaves the ridge with higher and lower parts, as well as gaps. Furthermore reef building biocenoses change shape and appearance of the eroding volcanic edifices.

Hawaiian (and other like for instance the Canarian) volcanoes go through stages during their lifetime with different production rates and magma composition. Connections to the magma chamber(s) may remain in place for some time while the volcanic edifice moves relative to the magma source(*), until it has moved so far away that rising magma seeks new ascent channels to rise and deformation forms new dykes and cracks and so it may erupt from different vents, and that from a possible complex and subdivided magma chamber(s) fed by the plume underneath.

That process may leave an appearance of single detached volcanoes like e.g. M. Loa and M. Kea, but they are just similar things at different stages. Many volcanoes never reach a subaerial state and remain submerged, contributing to the appearance of detached islands.

(*) i would say, whether it is the plate that moves or the plume or the connections between plume and magma chambers is mostly irrelevant. Base argument is that the rate is not constant and eruptions may seek different paths during time. As to the exact why and how, that's ongoing discussion.


Is CO2 in the Pacific Ocean depleted or enriched in Carbon-13 compared to the Atlantic, and why?

"The decrease in δ13C as water flows from the Atlantic to the North Pacific is due mainly to the addition of organically produced material and its subsequent oxidation as it falls through the water column. Marine organic carbon has a δ13C of near -250/00, hence the addition of this material decreases the δ13C of the ΣCO2." (from conclusion)

P. M. Kroopnick, Deep-Sea Research Part a-Oceanographic Research Papers, 1985, 32, 57-84.
https://www.sciencedirect.com/science/article/pii/0198014985900172


Do warnings verify better nearer radars?

This may/may not actually answer your question "Do warnings verify better" because of the qualitative word "better" and other factors that play a role, such as terrain and forecasting office. Another factor to consider is the nature of the warning and size of the phenomenon. A radar, for example, may not be the best tool to show verification of a hurricane, but it may be better for verification of a tornado. I hope to answer your question by taking arguments to the extreme.

If warnings verify more and more accurately as the warnings get closer to the radar, they may end up in the "cone of silence," where the angle of the radar would not be able to capture the phenomenon.

The opposite of that statement would be that warnings are more accurate the farther away the phenomenon is from the radar. This is also absurd, not only is resolution of the radar cut, but the curvature of the earth also makes this idea absurd.

Conclusion: there is some middle ground. If you get to close, you may not only be endangering your radar (depending on the phenomenon) but you may miss data. It also matters what angle your scan is at. I would hypothesize that anything within the highest elevation angle of the radar would have the highest accuracy, but it would really matter what the phenomenon warned is and what size the phenomenon is.

Warning zones are issued by people, and people have flaws. I would hypothesize that your results may not be conclusive, since the habits of each WFO may vary. For example, a winter storm warning in Georgia is an inch of snow and ice, while Boston would need 6 inches of snow to issue a winter weather watch. Some areas see tornadoes more often than others, leading to some inherent biases, etc.


Did climate cool down when underground hydrocarbons stocks formed?

Possibly

One thing you have to understand is that natural carbon sequestration via the formation of fossil fuel is VERY slow, it can take millions of years to build up the coal we burn in a day. In addition, one of the more dominant effects on the climate is solar radiance and continental position which changes over such long stretches of time, making matching such slow changes to carbon with climate change more difficult. Continent position also affects carbon sequestration and CO2 concentration directly making it even more confusing. Things like seaways and deserts can have huge effects on CO2.

The real problem is matching coal formation to changes in CO2 concentration.
Most coal comes from the carboniferous and the Permian time periods (along with the evolution of land plants that make it), the carboniferous saw severe cooling and severe drops in CO2. How much of this is CO2 lost to coal versus how much is just the formation of forests and other terrestrial ecosystems combined with changes in contingent positions is still up for debate.

The Permian however saw severe warming near its end and a rapid rise in CO2 at the same time, but most of it was relatively stable and unchanging both in CO2 and temp. It also included one of the largest volcanic events in earth's history, and again changing tectonic position. So although the link between CO2 and temperature is really well established we can't even say for sure such slow coal formation actually reduces atmospheric CO2 concentrations.

source

Compare CO2 above to temp (red line) below. Note that just three variables together predict temprature amazing well.

source


Will the oceans swallow all of the land?

If no new mountains were built, yes. Ultimately the processes of erosion would render the continents flat, and the seas would be left shallow and filled with sediments. The reason that this doesn't occur is that tectonic processes cause 'orogenesis', the formation of new mountains. The subduction of oceanic crust at plate margins is also responsible for trenches such as the Mariana, and ultimately recycles sediments into the mantle; thereby preventing the ocean floor from filling up.


Continuous lightning for over an hour; is this phenomenon common and does it have a name?

In Norwegian we call it kornmo (grain ripener); it happens in the late summer at a distance of more than 20 km so there is no sound.

The English translation is: "sheet lightning - heat lightning - summer lightning". I am not sure if this covers the meaning we have for it in Norwegian; it is said that Thor, the god of thunder, swung his hammer over the fields to get the grain ready for harvest.

This type of lightning is at more than 20km from the viewer and often 10-20 times this distance from you. It is really beautiful to see it.

This type of lightning happens high up in the atmosphere so one needs good viewing conditions to be able to see it. I do not think it is rare in itself; what is rare is the the atmospheric conditions that allow us to see it.

I guess this does not answer your question fully so I hope others post their answers too.


How CO$_2$ warming effect stays overnight?

CO$_2$ doesn't significantly interact with solar radiation or UV, and doesn't store any significant amount of heat. What CO$_2$ effectively does is scattering infrared radiation emitted by the Earth, and such radiation is emitted day and night. Let me explain this:

All objects emit a type of radiation called black body radiation. And the color (wavelength) and power of that radiation depends on temperature.
This radiation becomes evident to the eyes only at temperatures above 500 °C, when stuff start to glow, as amber, the heating element of a stove, the filament of a incandescent light bulb, or the Sun itself. However, this radiation is emitted also by colder objects, as the human body, the ocean and even glaciers and ice cubes. But we can't see that radiation because is very faint and mostly composed of infrared radiation that is invisible to the eye.

However it can be detected with cameras, and that's why military and surveillance thermal infrared cameras are capable to see in the night, because they see the radiation the human body emits. Here an example:

[picture from Videoblocks]

The interesting fact to keep in mind, is that for Earth to be in thermal equilibrium (meaning that the mean temperature is stable or changing very slowly), the amount of infrared radiation that Earth's emits have to be equal to the amount of radiation it receives from the Sun, so it is a lot!.

The effect of CO$_2$

Now, the effect of CO$_2$ is not to store any energy, it just blindly absorb and re-emit infrared radiation (foot note 1), there is no significant storage. The key point is that most of the infrared radiation it absorbs comes from the surface, and then it re-emits it in a random direction. As consequence of this, half of the radiation that was escaping to space is sent back to the surface, and that's the origin of the warming effect of CO$_2$.

So the effect of CO$_2$ is similar to that of a survival blanket like this one:

[image from Aliexpress]

This blankets don't produce or store heat, it is not good insulators either. This blanket just reflect back some of the infrared radiation that is leaving the body, effectively keeping it warmer. That's the same effect of greenhouse gases.

Let's imagine an atmosphere with no greenhouse gases. The radiation balance would look like this:

In this case the equilibrium temperature of Earth would be that on which the outgoing energy is equal to the incoming energy. That equilibrium would happen when the Earth's surface is at -18 °C, because at that temperature (according to Stefan-Boltzmann law that say that emitted energy $=\sigma T^4$), in average,  the black body radiation of Earth's (working day and night) would be powerful enough to equal the amount of energy we receive from the Sun during the day. So in this scenario Earth's mean temperature would be a freezing -18°C (like in the Moon).

But thankfully we have greenhouse gases, and the actual radiation balance of Earth looks more like this:

Here, half of the energy radiated by the surface is sent back to the surface by greenhouse gases (as a survival blanket does). This effect (greenhouse effect) warms up the surface. And it will warm the surface up until it emits enough energy such that the half of it that can actually escape to space is enough to equal the incoming radiation and reestablish the balance. Does that make sense?

In this simplified scenario that balance would happen at a nice and warm 30°C. Now, if we have too much geenhouse gases, this heating effect will overshoot and we will be too hot. That's what have people worried about: we are putting too many "blankets" on Earth.

Foot notes

1.- As a Chemist you might be interested that this infrared absorption capacity is related to the asymmetry of the CO$_2$ molecule and it's associated vibrational modes).


The processes forming obsidian are not well understood because an active obsidian-forming eruption has never been recorded by humans. However, we can make many inferences from the composition of the rock and settings in which it is found.

Obsidian is more than 70% weight percent SiO2 (i.e. rhyolitic), but has less than 0.5 weight percent H2O, and almost 0% gas bubbles (vescicles). This is very unusual because high-silica magma typically also contains a high volatile content. That means they can contain up to 8% H2O, CO2 and other species that easily become gasses. Because the rock is "missing" water and has no gas bubbles, we know that the gas escaped the rock while it was molten. This process normally takes quite a bit of time, so you might think obsidian cools slowly so that all the volatiles could diffuse out of the rock without forming bubbles.

If you thought that, you would be wrong.

Here's why: The SiO2 is almost 100% in glass form (amorphous) rather than in crystals. Any crystals that do exist are microscopic. This is strong evidence saying the rock cooled quickly, because if it cooled slowly the SiO2 would have had time to organize itself into crystals as it cooled. Further supporting the idea that it cools quickly is the fact that it is not observed underground (as an intrusive rock, which would have cooled slowly.)

One way to explain this "low volatile, glassy texture" paradox is to say the lava was kept hot for long enough time that the gasses were able to escape, and then cooled very suddenly. Another possibility is that the parental magma was extremely dry (low-volatile) to begin with for some reason.

Modern humans have never seen obsidian erupt primarily because rhyolitic eruptions are rare. However, obsidian is rare even among rhyolitic eruptions, presumably because lots of open-system degassing followed by rapid cooling is an unusual phenomenon. There are many places in the world that seem to habitually produce obsidian and have produced enormous volumes of it. The Valles Caldera in New Mexico is a particularly good example, with a huge lava flow and several lava domes all constructed from obsidian. Similar lava domes called the Inyo Domes near Mono Lake, CA have been fundamental to the understanding of the behavior of stable isotopes in magmatic systems and are probably the most well-known outcrops of obsidian among geologists.


Why is ground water rising on these forest rings?

Nobody knows - yet. But one can say that these rings are too numerous and too regular in shape to be related to either kimberlites or (even more bizarrely) Oklo-type natural nuclear reactors, as some have suggested.

For what it is worth, here is my own hypothesis: The areas concerned are all periglacial in an area of abundant boulder clay. In colder analogues, particularly in Siberia and further north in Canada, such environments contain 'pingoes' aka 'hydroloaccoliths', which are frost heaves in the shape of ice lenses. See, for example, https://en.wikipedia.org/wiki/Pingo . These are feedback processes of circular ice formations which develop in permafrost tundra areas. The circles you refer to are exactly the right shape, diameter, distribution density, and geology to be 'fossil' (melted) pingoes.

Consider what happens when a pingo develops. The ground is highly crazed with fractures over a disk shaped area. If there is brackish groundwater in the area then the ice freezes as pure water, thereby partitioning more saline groundwater to the perimeter - thereby leaving a high-salinity ring of brackish water which subsequently stunts tree growth (as you observe). When the ice eventually melts the pingo collapses to appear much like the surrounding boulder clay, but with a fractured and much more porous texture. Wherever there is a confined or semi-confined aquifer - which is very common because thick layers of impervious boulder clay behave as a confining layer - there will be a tendency for groundwater to rise as artesian (non-overflowing) conditions. Hence the 'bulge' of the apparent water table, which you also observe.  If this explanation is correct then the ring would be a natural exit and pressure release point for confined groundwater, and hence for entrained methane. Methane builds up under boulder clay, especially where the clay overlies peat deposits, such that oxidizing organic matter reduces the water. Moreover, this redox contrast, between surrounding oxidized near-surface/perched groundwater, and the reduced groundwater exiting from the ring, would also influence the nutrient availability, thus contributing to the ring of stressed vegetation.

As for the change in electrical potential, that is easily explained as deriving from the contrast between normal and residual more saline groundwater. Also, if the pingo was weathered during its evolution, then there would be a difference in clay content, which would also contribute to the electrical differential. Indeed, that is to be expected when a hill (the pingo) is drained by meteoric water, taking with it any dispersive clay (another common feature of boulder clay).

So no, sorry to disappoint, but the explanation is probably just normal periglacial hydrogeology - no gold deposits involved.

The test to verify this hypothesis? It needs someone to run a traverse across such a ring, measuring the hydrostatic pressure variation (horizontal and vertical), soil salinity, and soil clay content.


Which CMIP5 models give the highest and lowest warming for RCP8.5?

There is no model that consistently yields either highest or lowest warming because each model has strengths and weaknesses which depend upon the conceptual emphases. This varies with latitude, continentality, proximity of water/lakes, presence/absence of ice and mountains, regional significance of atmospheric processes - both physical and chemical, regional airflow strengths such as monsoonal and hurricanes, etc. Each model calibration works either brilliantly well, or downright dubiously, according to the model conceptualization. There is no 'one size fits all' (environments).

That said, however, I routinely use the CMIP-5 ensemble as listed in the World Bank Climate Change Knowledge Portal - just because it is convenient and readily available. You can find it at http://sdwebx.worldbank.org/climateportal/index.cfm - just click on the world map for your region / country / area of interest, and select the parameters you want. This is not the full ensemble, but 16 selected models that seem to work well - at least most of the time.

So here is a recent example from Nepal: scanning the maximum and minimum monthly temperatures, 'giss-r' generally yielded the hottest temperatures, although for occasional months the hottest was 'ccsm-4'. The coolest temperatures were mostly given by 'noresm 1-m' though for occasional months the coldest was from 'miroc esm'. However, this is just a random example. I do not believe that such conclusions are consistent everywhere in the world.

Why concentrate on the coolest and hottest models? Doesn't it make more sense to work with the ensemble median? I find that the relative distribution of model results is roughly similar regardless of the RCP. I usually quote RCP 4.5 or 6.0. RCP 8.5 is too pessimistic. Does anyone still seriously think that RCP 2.8 is attainable?

My advice is to spend a day picking temperature trends from the WB-CMIP model portal for a wide range of environments, and only then draw your conclusions.


How much net carbon can coral sequester?

Corals usually grow 1cm every year, some as slow as 2mm, some faster.

Coral sand density is about 1.5g /cm2, it's not the best estimate of coral weight. So, a coral organism of 10cm^2 produces 150 grams of CaCO3 every year, and 1m2 of coral can absorb 15 kilos.

CO2 is 44.01 g/mol
CaCO3 is 100.0869 g/mol

15kg * .44 is the absorbtion of CO2 of a coral organism of 1m2 surface area.
that's 6.6kg.

A car produces about 6 tons of CO2 every year.

Coral reefs are estimated to cover 284,300 km2 (109,800 sq mi), just under 0.1% of the oceans' surface area.

There are 1 billion cars, and 9 billion tons of antropogenic CO2.


Wikipedia does not include Alert as a port.  As the comments suggest, there is too much sea ice at that latitude to merit the infrastructure required of a port.  The northernmost port in the world is identified here as Dikson, Russia, at 73°30' N.
Supplies to Alert are delivered by air; the settlement does include an air port.


What was the likely composition of Earth's early crust (how did crustal composition evolve)?

Gordon's answer is correct to a first order approximation.

However, the zircons that were found in Jack Hills are from the Hadean, more than 4 billion years ago. The fact that zircons that old exist is interesting - zircon is not a mineral you find in mafic rocks. Zirconium is an incompatible element in the mantle, so to get enough of it to form its own mineral you need some partial melting events. This may also be of interest:

What are the high field strength and large ion lithophile (HFS or HFSE & LIL or LILE) elements?

When you melt the mantle, you end up having basalt or more felsic rocks. If you have enough zircon in mafic rocks, you form baddeleyite: ZrO2. Zircon, ZrSiO4 will only form in more felsic rocks, where you have enough Si. This alone suggests that some parts of the early crust was somewhat more felsic than a basalt.

There's more to it: inclusions of quartz and oxygen isotope data indicate that not only the zircon was in a felsic rock, it has evidence to suggest liquid water and hydrothermal alteration.

This entire thing is heavily debated, because there's only so much you can tell from a few grains of zircon. However, the basics are there - some felsic rocks existed as far as the Hadean.


Can volcanic gases be emitted in any other way besides volcanic eruptions

Volcanic gases are emitted by a number of ways besides eruptions:

Dissolved gases in heated groundwater.

Using a geothermal complex like Yellowstone National Park along Wyoming-Montana border in USA, volcanic gases are emitted through groundwater and water vapor from heated geothermal springs.  One of the most impressive aspects of Yellowstone is that steam rises from everywhere: in parking lot storm drains, potholes, not just from the geysers or springs.
Gas venting from volcanic crater when the volcano is not active.

Gases will vent from volcanic craters between eruption cycles. The emitted gases can be used to determine the level of activity beneath the surface by monitoring volume and chemical composition. Changes in volume and composition can indicate a change in activity up or down.

Often the gases emissions are not visibly noticeable.
Gases can be emitted from a underlying magma chamber through cracks and fissures.

Mount Nyiragongo in Congo has localized carbon dioxide toxicity, known locally as 'mazuku' which are where the gas seeps from the ground in relatively high levels, without the dispersing effects of wind.  This can occur miles from the volcano's summit.

The Great African Rift complex has numerous lakes where CO2 build is a serious concern.
Strongly stratified lakes can trap large amounts of CO2 deep within the lake.
This is evidence that volcanic gases can be emitted across a wide area over a volcanic complex not limited to surface boundaries of a volcano.


A part answer to your question.

According to the article Palaeoceanography: The briny deep (Martin, 2008), explains the reason for the use of the neodymium ratio as being

  The isotopic signature of a water mass is imparted from weathering of continental material in the region where the water mass sinks below the surface. Radiogenic Nd isotope values reflect a contribution from relatively young volcanic material, whereas non-radiogenic values are a consequence of inputs from old continental crust. The water mass carries its distinctive signature as it circulates through the oceans.

Its stability is described in the paper Temporal stability of the neodymium isotope signature of the Holocene to glacial North Atlantic (de Flierdt et al. 2006), as being due to the observations that Nd isotopes

  are not thought to be altered in any significant way by biological processes, and thus can serve as a quasi-conservative water mass tracer.


Coupling recharge with 1D groundwater flow model

If you are not interested in the vertical flow occurring in your aquifer (which I assume is the case) then one can indeed add the recharge to the existing head!

In groundwater issues, we often assume the recharge to be constant over time and equal over distances when considering such problems. This is mainly due to simplification as we are often interested in horizontal flow rather than vertical flow.

That being said, in general I would consider recharge (as this seems to happen outside the system we are interested in) as a constant rather than a boundary condition.

However, when going into details, considering boundary conditions there are several ways to go:

Dirichlet boundary conditions: Where we assume a constant head at a certain location. As we go from A to B, we could assume constant heads at these location(s), depending on your setup.

Neumann boundary conditions: Where we assume a constant input/output discharge at a certain location. This could also be your recharge but also dependent on your setup.

Cauchy boundary conditions: complex combination of the two where the input is related to a head. An example of this could be a river with head h_x feeding an adjacent confined aquifer with head h_x2

I hope this gives some insight in the application of appropriate boundary conditions. As you can see: it all depends on the characteristics of the system, the known values and your own considerations.

For further reading one might consider Fitts' Groundwater Science (fully available at ScienceDirect)


How high must one be for the curvature of the earth to be visible to the eye?

Depends on your eye. You can realise the curvature of the Earth by just going to the beach. Last summer I was on a scientific cruise in the Mediterranean. I took two pictures of a distant boat, within an interval of a few seconds: one from the lowest deck of the ship (left image), the other one from our highest observation platform (about 16 m higher; picture on the right):

A distant boat seen from 6 m (left) and from 22 m (right) above the sea surface. This boat was about 30 km apart. My pictures, taken with a 30x optical zoom camera.

The part of the boat that is missing in the left image is hidden by the quasi-spherical shape of the Earth. In fact, if you would know the size of the boat and its distance, we could infer the radius of the Earth. But since we already know this, let's do it the other way around and deduce the distance to which we can see the full boat:

The distance $d$ from an observer $O$ at an elevation $h$ to the visible horizon follows the equation (adopting a spherical Earth):

  $$
d=R\times\arctan\left(\frac{\sqrt{2\times{R}\times{h}}}{R}\right)
$$

where $d$ and $h$ are in meters and $R=6370*10^3m$ is the radius of the Earth. The plot is like this:

Distance of visibility d (vertical axis, in km), as a function of the elevation h of the observer above the sea level (horizontal axis, in m).

From just 3 m above the surface, you can see the horizon 6.2 km apart. If you are 30 m high, then you can see up to 20 km far away. This is one of the reasons why the ancient cultures, at least since the sixth century BC, knew that the Earth was curved, not flat. They just needed good eyes. You can read first-hand Pliny (1st century) on the unquestionable spherical shape of our planet in his Historia Naturalis.

Cartoon defining the variables used above. d is the distance of visibility, h is the elevation of the observer O above the sea level.

But addressing more precisely the question. Realising that the horizon is lower than normal (lower than the perpendicular to gravity) means realising the angle ($gamma$) that the horizon lowers below the flat horizon (angle between $OH$ and the tangent to the circle at O, see cartoon below; this is equivalent to gamma in that cartoon).  This angle depends on the altitude $h$ of the observer, following the equation:

  $$
\gamma=\frac{180}{\pi}\times\arctan\left(\frac{\sqrt{2\times{R}\times{h}}}{R}\right)
$$

where gamma is in degrees, see the cartoon below.

This results in this dependence between gamma (vertical axis) and h (horizontal axis):

Angle of the horizon below the flat-Earth horizon (gamma, in degrees, on the vertical axis of this plot) as a function of the observer's elevation h above the surface (meters). Note that the apparent angular size of the Sun or the Moon is around 0.5 degrees..

So, at an altitude of only 290 m above the sea level you can already see 60 km far and the horizon will be lower than normal by the same angular size of the sun (half a degree). While normally we are no capable of feeling this small lowering of the horizon, there is a cheap telescopic device called levelmeter that allows you to point in the direction perpendicular to gravity, revealing how lowered is the horizon when you are only a few meters high.

When you are on a plane ca. 10,000 m above the sea level, you see the horizon 3.2 degrees below the astronomical horizon (O-H), this is, around 6 times the angular size of the Sun or the Moon. And you can see (under ideal meteorological conditions) to a distance of 357 km. Felix Baumgartner roughly doubled this number but the pictures circulated in the news were taken with very wide angle, so the ostensible curvature of the Earth they suggest is mostly an artifact of the camera, not what Felix actually saw.

This ostensible curvature of the Earth is mostly an artifact of the camera's wide-angle objective, not what Felix Baumgartner actually saw.


Temperature change in Earth atmosphere models?

There's some kind of explanation about the units under the picture. The formula is based off the average temperature in degrees Celsius (measured over the entire year, and the entire Earth), which is 15.04 at sea level, and the temperature decreases by 0.00649 degrees every meter above sea level (the average lapse rate). The formula is 'valid' until 11 kilometers, where the troposphere ends.
It's just a model of the average temperature; of course, at the poles it will be colder and at the equator it will be warmer. The lapse rate also varies, while the average of 6.5 °C per kilometer is quite well-known, it can vary between 9.8 °C when it's dry and about 5 °C when it's moist; see Wikipedia for the derivation of these rates.


What caused the high temperatures that resulted in the Cretaceous aged komatiite lavas of Gorgona Island, Colombia?

There are some suggestions in the recent paper in Nature Geoscience about Tortugal lava suite. The suite formed 89 million years ago and recorded mantle temperatures as high as Archaean komatiites. The mantle plumes are chemically and thermally heterogeneous, so the researchers interpret these rocks as the result of melting the hot core of the plume head that produced the Caribbean large igneous province. Their results imply that a mantle reservoir as hot as those responsible for some Archaean lavas has survived eons of convection in the deep Earth and is still being tapped by mantle plumes.

The link: https://www.nature.com/ngeo/journal/v10/n6/full/ngeo2954.html


I don't totally understand what you are asking but yes there was soil in the Archean. In some locations around the world, these soils were buried and preserved as paleosols. The Archean paleosols are very important in studying the origin of the atmosphere because the oxidation state of the minerals is an indicator of the presence or absence oxygen and other gases in the atmosphere (Mukhopadhyay et al., 2014)


How can I calculate the average latitudinal temperature anomaly between a city and all other locations along the city's latitude?

I think you'd be looking for a gridded dataset, where data has been interpolated to a grid of the Earth, rather than one that has data at particular points (eg. stations). I'm probably not the best person to recommend one particular gridded set over another, but a good start might be the Met Office's HadCRUT4 set, which combines gridded surface temperature data over both land and sea.

I haven't looked at HadCRUT4, but I daresay it'll come (either in plain text or NetCDF format) as a lat/lon/time array (grid), and if you're interested in a particular latitude, you should just be able to read off a latitudinal row. Then you can look at it however you like: subtract the temperature of the point closest to your city from the rest to get an anomaly right across the latitude, or average the whole thing (a zonal average) and subtract the city baseline from that. Hope that helps :)

Edit: HadCRUT4 is a monthly dataset. If you're looking for more temporal resolution (the weather tag suggests to me that you are), I'm not sure what availability among gridded sets is like, but you could try taking a station set (eg. HadISD, which is hourly) and gridding it yourself.


With so many positive feedbacks accelerating global warming, how did the earth ever re-enter ice ages after it came out of one?

It is not only Milankovic cycles, these are often overrated.

Starting in the Cretaceous, thoughout the Paleo- and Neogene the world went from a greenhouse to an ice age that culminated in the Pleistocene. Much is attributed to the arrangement of continents (large landmass to the southpole), change in ocean currents,
and slow accumulation of ice shields and rising albedo. This is a positive feedback actually, whose reversal (observations from Greenland and recently even Antactica) have led to corrections in climate models, making the projected ocean level rise and arrival of tipping points that will develop their own dynamic even worse. This is very concerning !

But back to the question with two examples, that can be researched:

First, when Antarctica and Australia separated ~35My ago, a circumpolar current developed that cut off the continent from global circulation so that the iceshields could be maintained and more accumulated.

Second, when the isthmus between the Americas closed ~3My ago, ocean currents changed, the gulf stream developed that transports heat and moisture to Europe and north eastern America. The gulf stream can switch states (See: north atlantic deep water (NADW) forming), changing temperature and precipitation patterns, contributing to ice shield build up and retreat in the north.

These are just a few highlights to answer how the earth entered the current ice age, there would be much more to write. Other "ice houses" in earth's history (e.g. Permian glaciation) may have had other causes.

Hope that helped a bit :-)

Edit: but a related, mesmerizing question is: if a hypothetical global ice age really existed, how did the earth find out of that ? The high albedo from a global snow/ice cover would prevent that. Somebody painted it black :-) ?


Why is Mauna Kea taller than the maximum height possible on Earth?

Since over half of the height of Mauna Kea is under water, you need to consider the buoyancy effect. Instead of a density of $3 \times 10^3\ \mathrm{kg/m^3}$, the underwater portion has a net density of $2 \times 10^3\ \mathrm{kg/m^3}$. That will significantly increase the potential height of such a mountain. Add in all the other uncertainties (is Mauna Kea made of rock with "typical" elastic limit and density? is it even homogenous? are there dynamics involved? and what about Naomi?) and there's no reason to see its height as a contradiction.


Is there any river that does not discharge into larger body of water?

The Okavango River is a good example of this. It drains into a swampy delta in the middle of the Kalahari desert:

The Okavango Delta, CC BY Justin Hall.


What's the difference between the upper & lower mantle?

The boundary between the upper and lower mantle is today believed to be due to the phase change because of increasing pressure of:

$$\text{Ringwoodite} \xrightarrow{\text{660 km, about 24.5 GPa}} \text{Mg-Perovskite} + \text{Mg-Wüstite}$$

The boundary was originally found in the form of a seismic discontinuity (the "660 km discontinuity"). This information was combined with the knowledge that the most primitive meteorites have roughly the chemistry of the bulk Earth. Accounting for the chemical differentiation (into crust, mantle and core) the chemistry of the mantle was known. Additional clues for the chemistry come from mantle-xenoliths. The crystal structure (important for the density of a chemical compound or mineral) can be deduced from high pressure experiments and natural laboratories such as meteorite impact craters. For example, the mineral majorite was found, which is also postulated for the lower mantle.

Some literature on this: http://mahi.ucsd.edu/shearer/PDF/30NT92a.pdf


Was climate change inevitable anyway, or is there more to it?

Earth's climate has changed in the past and will change in the future. It would have changed even if we didn't start spewing enormous amounts of CO2 to the atmosphere. The main difference here is the rate at which this is happening. Natural climate change unfolds over thousands or tens of thousands of years (btw - PETM was fairly rapid, but we don't know exactly how rapid). Current climate change happens much faster. You can see temperature records broken every single year.

Our modern civilisation developed in a fairly stable climate. We did not develop in a climate where we had ice-free poles, or higher sea levels. The geopolitical consequences of altering that too fast would be simply too much.


Continental collision – evidence left of river mouths and estuaries along the boundary?

There were certainly river mouths or estuaries in the rivers that drained off the proto-Himalayas into the last retreating stages of the Neo-Tethys Ocean. Such rivers comprised dozens of small rivers and the westward-flowing Proto-Ganges itself, which deposited the Siwalik formation which now forms the Lesser Himalayas. That is, the southernmost 'soft' 'salt and pepper' sandstones, up to about 2500 metres , which now abut the Indian plain. However, there is almost nothing left in terms of recognizable estuarine sedimentary structures. It has all been compressed, folded, imbricated, overthrust and subject to varying degrees of diagenesis and cataclasis. Most of this sediment was meandering mud flats, sandy outwash and restricted shallow marine sediments, with some similarities to the 'cuvette' environments of the European Old Red Sandstone.

As to the second question, your mention of the closure of the Tethyan Ocean  leading to the Indian-Tibetan collision suggests that you already suspect (correctly) that the Ganges is a case in point. It's headwaters were  originally in southwestern China, and it originally flowed westwards along the foot of the proto-Himalayas (what is now the high Himalayas)and out to the Indian Ocean somewhere in the vicinity of what is now the Indus basin in Pakistan. As continental collision progressed there was continental up-warping in what is now  the Himachal Pradesh area of India. This reversed the Ganges drainage so that it now flows eastwards.
This has important modern implications, as it was the originally westward-flowing Ganges that brought arsenic from the marine Tethyan sediments of western China, and which is now the source of the arsenic groundwater problem over much of Bangladesh and adjacent areas.
See also my paper: http://link.springer.com/article/10.1007%2Fs10653-005-7102-9   But don't pay the exorbitant price! - I can send you the original text for free! :-)


What is "focus point" in WRF-plots grid box? (python code)

A Skew-T/Log-p plot is a vertical profile from a point, and it appears in that code that the point you are plotting the skew-T for is 60.2 latitude, 11.08 longitude.  The snippet of code:

def getXY(lon,lat):
 x_nr = 0
 y_nr = 0
 while (lon[x_nr] < lon_focuspoint):
  x_nr += 1
 while (lat[y_nr] < lat_focuspoint):
  y_nr += 1

finds the closest grid point west and south of your focus point by setting the x and y gridpoints to 0 and incrementing the index as long as the latitude/longitude values at that grid point are less than the focus point.  This is what the focus point is for -- the lat/lon location you want the skew-t/log-p plot at.

The exception IndexError: index out of bounds. means that the above code tried to access a value lon[x_nr] or lat[y_nr] that was out of bounds.  This means that the latitude/longitude coordinate of your focus point is not within your domain.

To run the code successfully, edit the focus point to be a point within your model domain, specifically the value of latitude and longitude that you want the skew-t profile for.