How are aquifers found and traced? Recently a line from a news article about an aquifer in the path of a tunnel boring machine for Metro networks caught my attention:

  Ahead of tunnelling, the builders conduct hydrogeology, a study of water flow in aquifers and characterization of
  aquifers. During our study, the aquifer wasn’t identified,” said an engineer.

This led me to wonder how aquifers and underground water flow are detected, studied and mapped out. I searched the net but couldn't find anything relevant.

So, how are aquifers detected and their courses mapped?

Aquifers are relatively permeable zones of material that transmit water. Common aquifer materials include layers of unconsolidated sedimentary rock, like sands and gravels; and poorly cemented “bedrock” units like sandstone. Interconnected solution cavities in limestone, called karst, are common in some areas. Calling something an “aquifer” generally infers that the unit is capable of producing enough water via a well to be of interest to humans.

Aquifers are typically delineated using geologic and geophysical logs of boreholes from wells and test holes. These kinds of logs are typically required to be provided to a specified public agency for future use by others. Using these logs, a geologist can create cross sections of an area to evaluate the extent and thickness of these units. This is done keeping in mind the geometry of how these were originally deposited, such as linear streams, sheet-like sands, etc.

Surface geophysical techniques can also be used to assess subsurface conditions, but typically require “ground truth.” I remember asking a geophysicist what his data were telling him about an area, and he said, “I won’t know until you put some drill holes in.” It wasn’t as bad/funny as it seem. He could help color in between the data points, but first he needed to know what the specific geophysical response he was seeing meant as far as real rock present in the subsurface.

It should be rare to hit an aquifer zone unknowingly, as you described. It’s possible they hit a permeable fault zone, which can be tricky to know about beforehand. But I need to mention that engineers are notorious for keeping geologists out of the loop until a problem arises. They often don’t want to pay for upfront studies, the kind that geologists use to assess such things.


How does friction and radiolysis provide hydrogen for "unusual types of methane"? The fascinating New York Times article Gas That Makes a Mountain Breathe Fire Is Turning Up Around the World talks about the Flames of Chimaera and the Deep Carbon Observatory:

And a series of studies published by a group of international scientists known as the Deep Carbon Observatory is showing that this source of gas is more common on our planet than previously known.
“We have discovered these unusual types of methane in many, many sites. It’s not a rare phenomenon,” said Giuseppe Etiope, a member of the group who helped discover the cause of the flames of Chimaera in 2014. (emphasis added)

This question is about the possible sources of hydrogen that resulted in what the NYTimes calls  "unusual types of methane":

For years, Deep Carbon Observatory researchers have collected and analyzed gas samples from hundreds of diverse sites. And using special tools to figure out where the methane came from, they’ve discovered Earth’s basic recipe: Take hydrogen from water. Mix with inorganic carbon from minerals or gas. Add another metal-rich mineral to get the process going, and voilà — abiotic methane.
The hydrogen often comes from serpentinization, when water percolates usually through rocks from the mantle. But the recipe varies. Different sites may use different minerals or carbons sourced from their environments: Hydrogen may come from friction, or radiolysis, instead of serpentinization. Temperatures may range from below 250 degrees Fahrenheit, which can still support life, to some 900 degrees Fahrenheit, which can’t. (emphasis added)

Serpentinization is nicely explained in @Gimelist's excellent answer to the question What is serpentinization, in the context of disappearance of surface water on Mars?
Question: How can the hydrogen in this abiotic methane come from

Friction
Radiolysis

Possibly helpful (Open Access):

Etiope, G. and Whiticar, M. J. 2019 Abiotic methane in continental ultramafic rock systems: Towards a genetic model
Etiope, G. and Ionescu, A. 2014 Low‐temperature catalytic CO2 hydrogenation with geological quantities of ruthenium: a possible abiotic CH4 source in chromitite‐rich serpentinized rocks

I found this paper 1 trying to understand what is radiolysis. The decomposition of water by ionization happens at basaltic aquifers on the seafloor, close to seabed.

  "Water radiolysis is the decomposition of water molecules by ionizing
  radiation produced during the decay of radioactive elements (Debierne,
  1914; Le Caër, 2011). The principal radioactive elements that produce
  ionizing radiation in basalt are uranium (238U and 235U), thorium
  (232Th), and potassium (40K), which collectively emit alpha (α), beta
  (β), and gamma (γ) radiation as they and their daughter nuclides
  decay. Transfer of energy from this radiation excites and ionizes
  water molecules, producing several chemical species: eaq-, HO•, H•,
  HO2•, H3O+, OH-, H2O2, and H2 (Spinks and Woods, 1990; Le Caër, 2011)."

  "The oceanic basement contains the largest aquifer on Earth. Its
  fractured rock contains nearly 2% of Earth’s total volume of seawater
  (Johnson and Pruis, 2003). Although the extent of life and microbial
  activity in oceanic basement is not well known, a variety of evidence
  suggests that microbes reside within the aquifer (Cowen et al., 2003;
  Edwards et al., 2012; Jungbluth et al., 2013; Lever et al., 2013;
  Orcutt et al., 2013). Fisk et al. (1998) and Staudigel et al. (2008)
  report weathering textures suggestive of microbial alteration in
  subseafloor basaltic glass."

  For subseafloor environments, we are particularly interested in the
  production of the reductant H2. Many organisms catabolically utilize
  H2, including methanogens, sulfate-reducers, iron reducers, and
  nitrate reducers (Fang and Zhang, 2011). There is evidence that some
  of these organisms, specifically sulfate reducers and methanogens, are
  active in subseafloor basalt (Lever et al., 2013). Radiolysis
  undoubtedly occurs in subseafloor basalt, as both water and radiation
  are present. Edwards et al. (2012) suggested that in the old and
  relatively weathered basaltic basement of the South Pacific Gyre
  (SPG), radiolytic H2 may be the dominant electron donor.

Trying to understand how hydrogen can be formed by friction I found this other one 2 where the author asociates it to earthquakes, listing three possible origins for hydrogen and saying the frictional origin is still a not well known process. Apparently it happens at fault systems when there are mouvements on lithosphere:

  In the last few decades, three different abiotic H2 generation
  processes have been proposed:

  (1) water–rock redox reactions, mostly under hydrothermal conditions    [Janecky and Seyfried, 1986; Coveney et al., 1987],
  (2) radiolytic reactions of H2O [Savary and Pagel, 1997], and
  (3) mechanoradical formation on wet fault surfaces during earthquakes    [Wakita et al., 1980].

  H2 production by peridotite‐
  water and komatiite‐water hydrothermal reactions, as modern and
  ancient analogs, respectively, has been quantitatively estimated in
  laboratory experiments [Seyfried et al., 2007; Yoshizaki et al.,
  2009]. Radiogenic production of H2 is supported by the analysis of
  H2‐bearing fluid inclusions in quartz containing U‐bearing minerals
  [Dubessy et al., 1988], and has been quantitatively estimated in a
  laboratory g‐irradiation experiment [Lin et al., 2005]. The H2 flux
  per unit of surface area from redox reactions has been estimated to be
  3 × 10−4 mol/m2 yr from a 1 km column of mafic/ultramafic rock with 10
  wt% FeO [Sleep and Zoback, 2007], and the estimated flux from water
  radiolysis in the Witwatersrand basin, South Africa, is 8 × 10−6
  mol/m2 yr [Lin et al., 2005]. In contrast, the H2 flux associated with
  earthquakes and its significance in subsurface ecosystems has not yet
  been explored in either the field or laboratory.

After making experimental flux calcs the paper says this mechanism may have been important for methanogens. And not only eartquakes but meteorite impacts too may have been a source of mollecular hydrogen for primigenious  life not only on Earth but on other planets.

  "Thus, seismic activity and the consequent release of H2 might have
  sustained subsurface microbial communities as long ago as 3.8 Ga.
  Moreover, mechanoradical H2 generation can be induced by meteorite
  impacts as well as by earthquakes, and thus might play an important
  role in the evolution of subsurface biosphere not only on Earth but
  also on other planets."

1 Dzaugis Mary E., Spivack Arthur J., Dunlea Ann G., Murray Richard W., D’Hondt Steven (2016). "Radiolytic Hydrogen Production in the Subseafloor Basaltic Aquifer" Frontiers in Microbiology, 7, ISSN=1664-302X

2 T Hirose, S Kawagucci, K Suzuki (2011) "Mechanoradical H2 generation during simulated faulting:
Implications for an earthquake‐driven subsurface biosphere." Geophysical research letters.


Can runaway methane gas emissions be an extinction level event? Much ado has been made by a few petroleum engineers and global-warming alarmist about all of the methane gas trapped in frozen form, mostly on the ocean floors.

The "What-if" scenario begins to play out in 2080 or so, when a few petroleum engineers claim that the skies will start to turn a brownish color, making the earth even hotter.

These comments are buried deep in old magazine articles and by now these engineers are probably working for another employer. Even Al Gore did not say much at all about natural frozen methane gas being set free in massive quantities. But a few geologist and alarmist say it will happen as expected.

Even if it comes true, questions abound about what year it maybe dense enough to make the Earth like Venus. Will it mean that as it builds up it will move closer to the ground and begin to poison us directly? Birds will drop out of the sky by the millions. Animals will move down from tall mountains. 90% of the human race could die off, but some would die from ignorance, like in hurricane Katrina.

Would this be the toxic gas that could "Shroud the world" within the next 100 years? Someone please prove this is wrong, or at least there are "workarounds" for the problem.

IF, and it's a very big IF, all the methane hydrate were to be released rapidly, then the planetary climate would be stuffed. But it won't happen.

How much methane hydrate will be released due to global warming? Run 30 different atmospheric-ocean-coupled global climatic models, and you will get 30 different answers - all of them based upon arguable assumptions. The scaremongering doomsayers love to fanfare the worst case. In which case, some of your dire forebodings may come about. But first, take a balanced view of the physical reality. The vast majority of all the world's methane hydrate is sufficiently deep, on or in the sea floor, that it will be millennia, if ever, before they melt, thereby contributing to global warming. The deep ocean floor is everywhere only a few degrees above freezing, whereas almost all of the oceanic warming is in the uppermost few hundred metres. Check out the diagram in http://worldoceanreview.com/en/wor-1/ocean-chemistry/climate-change-and-methane-hydrates/ and you will see that the pressure-temperature control is such that most of the methane hydrate will always be stable.

The current consensus is that some methane is already being emitted from the thawing tundra, mainly in Siberia, Canada and Alaska, and some more will be released from shallow seas as and when they warm up. But this won't dominate the global warming process. In fact methane release is just one of at least two dozen feedback processes, some negative but mostly positive, which will influence the rate of global warming for the next few centuries.

Making the world 'toxic', or 'like Venus' or the 'atmosphere turning brown', or 'poisoned birds dropping out of the sky' are all absurd, but that's no reason for complacency. The rise in global atmospheric methane amounts to about 6 parts per billion per year since 2006, or slightly more than 6 ppb in polar regions; significant, but not at all catastrophic. I am far more worried about the accumulating global CO2, which still shows no sign of slowing down despite a dirge of conference resolutions, ineffective carbon taxes, and empty political rhetoric.

As for an 'extinction event', the extreme rapidity of global warming, habitat loss, sea level rise, and ocean acidification, all adds up to the fact that we are already in an extinction event - not for humans, most of whom will be able to engineer their way through a 3 to 4 degree C global temperature rise, but for the rest of the biosphere - with, or without, extra methane.

Notwithstanding the scientific facts, maybe we can all relax, because Donald Trump assures us that climate change is just a fictitious Chinese conspiracy.


A few questions about glass A glass, as I understand it, is a material whose solid phase is amorphous and which undergoes a glass transition when heated.

My train of thought - and therefore my questions - began with obsidian.  My understanding is that obsidian is formed from material that would normally form crystalline rock, but since it's exposed to air during an eruption, it cools too rapidly to crystallize and therefore solidifies as glass.  This led me to wonder: how large can a lava stream be and still produce obsidian?  In particular, in season 7 of Game of Thrones, the island of Dragonstone is revealed to contain a veritable mountain of obsidian - is such a thing possible in the real world?  I would have thought that, above a certain volume, the center of the mass would be well-enough insulated so that crystallization could occur, spoiling the obsidian.  What's the largest mass of obsidian found in nature?

Thinking about too-rapid cooling led me to another question: can water form glass?  Is it possible to blast-freeze water so quickly that ice crystals do not form?  If so, what would be the properties of such a glass?

Finally, I wonder about regular, garden-variety silicate glass (as found in windows and bottles.)  Can it be cooled slowly enough so that crystals do form?  And if so, what are its properties?  (Have I essentially re-invented quartz?)

Q1: A volcano consists of many lava flows that occur over a long period of time.
In general, only very few of these lava flows have the right composition and  the right cooling history that are required to form obsidian.

This is why only parts of a volcano consist of obsidian, and by volume it's a generally a very small amount.

Q2: And yes there is amorphous ice. It is known since the 1980s. These days it is being used in laboratory environments, e.g. for electron cryomicroscopy. This is a high-tech-method for observing biochemical reactions and cellular processes in situ. The microorganisms need to be alive and in the middle of a reaction when shock-freezed. Researchers want to image atomic structures of the biomolecules, not from ubiquitous crystalline water so it better be amourphous.

Q3: Glass from windows and bottles contains more Na and K than most Granitic rocks. Na- and K-rich ingredients are being added as fluxing agent (limestone, soda), in the glass factory, decreasing the melting point of the silicates and therefore lowering the production costs.

I think a melt of bottle glass, when crystallizing slowly would initially form the minerals Nepheline and Leucite, but late in the solidifcation process also Alkali Feldspar, and some Quarz, among other minerals.

If you cooled it so slowly that no glass phase forms, you still might get zoned crystals, having with a different composition from core to rim. That depends on the absence/presence of impurities and local chemical (dis-) equilibria.


If all the world's ice were to melt, would this shift the earth's centre of gravity with consequential effects on sea levels? This question on Maths SE asked how we might calculate the effect on sea level if all the world's ice (ie including the whole Antarctic ice sheet) were to melt. I posted an answer containing calculations suggesting - and this came as a surprise to me - that the rise in sea level would be up to about 40 metres more at high northern than at high southern latitudes.  The key qualitative assumptions underlying this conclusion are:

Most of the world's ice is in the Antarctic ice sheet.
The melting of all the world's ice and spread of the resulting
liquid water across the oceans would result in a shift in the
earth's centre of gravity.  Given 1 above, the shift would be
towards the north.
The shift in the earth's centre of gravity would not significantly
affect the position of the earth's land masses and ocean bed which
in this context can be regarded as a solid mass around which the
ocean water would position itself.
The distribution of liquid water across the world's oceans, though
affected by other factors, is largely determined by the
gravitational force pulling it towards the earth's centre of
gravity.  Hence a northward shift in the centre of gravity would
pull a slightly larger proportion of the ocean water to the northern
hemisphere.

Are these assumptions broadly correct?

As a prescript, your question is firmly within the field of Glacio-Isostatic Adjustment (GIA) modeling of the Earth and the sea level. The main scientific names doing research in this direction are Jerry Mitrovica, W.R. Peltier, Roblyn Kendall, Glenn Milne, Kurt Lambeck, Giorgio Spada, and probably some more that I'm forgetting. It all comes down to, basically, the 'Sea Level Equation' (SLE), https://en.wikipedia.org/wiki/Sea_level_equation .

Copying straight from Wikipedia, the simplest form of the sea level change $S$ is given by the difference between the shift in the geoid (i.e., the effects you describe) $N$ and the changes in vertical land positions ($U$):
$$ S = N-U .$$

It is this second factor, the response of the Earth and ocean bottom to the changing loads, that you didn't take into account, that can lead to some serious local deviations from the gravitational aspect alone.

See Figure 2-2 from http://skb.se/upload/publications/pdf/TR-09-11.pdf, copied here below:

Figure 2-2. (a) Ocean height is perturbed upwards due to the gravitational attraction of the ice sheet. Solid Earth is depressed downwards due to the mass of the ice sheet. (b) Local relative sea-level fall due to a decrease in gravitational attraction by the ice (red dashed line shows previous position), combined with solid Earth rebound (green line shows previous positions) due to the ice sheet having a smaller mass. Far-field sea-level rise is due to the addition of meltwater into the ocean. Adapted from Tamisiea et al. 2003.

After staring at this figure for a while, you may appreciate that, indeed, from state (a) to (b) as the ice cap melts, the far-field sea level rises through addition of fluid water and a drop in the gravitational attraction nearby. However, also, now that the ice cap is smaller and less heavy, the solid Earth responds by moving up! Hence, 'close' to the ice cap, the sea level doesn't drop as much as you would expect from amount of fluid water + gravity alone. NB: the same happens with the oceans: adding more water to the oceans depresses them, see page 26, figure 11 here https://arxiv.org/pdf/1212.5061.pdf  with the 'relative sea level change' around the Mediterranean Sea, compared to the present. Copied here below is one for 10 thousand years ago:

Apparently, the sea level has risen by 30 meters in the center of the sea, but only about 22 meters on the edges. The reason is that the Mediterranean sea, from 10 thousand years ago to today, gained more mass, which caused it to depress the sea bottom / Earth's crust in the center! Hence, it had to rise even more in the center (compared to the coast lines) to create a flat surface today.

The difficult thing is that these are non-local processes. You kind of need to know about such local Mediterranean changes to make an accurate prediction for the sea level in, e.g., the Gulf of Mexico or so, because it changes the center of mass and the fluid sea water budget that can be distributed!

So with respect to your question, I absolutely think you are right that gravity is an important aspect, and 40 meters relative sea level change differences due in the hemispheres are absolutely possible for the reason you mention. If the melting is instantaneous, this is the main aspect. However, if you wait a century or so, the Earth's deformations start to kick in, can play a serious role, and can dramatically affect the sea level distribution again, in not easily foreseeable ways!


How deep is the permafrost in the Antarctic? I tried in vain to find the answer to this question on the web, but all it would tell me was, "it is very deep", and "it is known as a thaw line rather than a frost line in the arctic and antarctic". How far down you would have to live to escape the permafrost? 100 ft? 1000 ft? 10000 ft?. How feasible would an underground base be?

According to "Permafrost, active-layer dynamics and periglacial environments of continental Antarctica" South African Journal of Science 98. pages 82-90:

Only 25% of Antarctica has permafrost, as the material beneath thick ice sheets is not permafrost.

The deepest permafrost occurs where there is no ice sheet.

The deepest permafrost in the Antarctic is about 1000m.


Hydrocarbon resources extension. How? Pardon my naive question. But I heard this argument quite sometimes.
One can find at the Schlumberger careers page the particularly interesting FAQ:
“We are often told that oil is running out. Why should I join an aging industry?”
The answer is:
Far from joining a dying industry, technology is ensuring that hydrocarbon resources will be extended, that the amounts recovered will increase and the challenges the technology represents will remain as exciting as ever.
My question is what exactly is meant by “hydrocarbon resources will be extended”? Is the oil refilling somehow?

The quantities of oil in a deposit are listed under two categories: resources and reserves.
Resources are deposits that could be converted to reserves if economic factors, prices and costs, were favorable.
Reserves are deposits that can be extracted for a profit.
What makes a deposit profitable involves many things:

The size of the deposit
The quality of the deposit - the type of hydrocarbons in the deposit,
is it lighter fractions of oil or heavier or a mixture of the two. It
also depends on the amount of undesirable contaminants in the oil
such as sulfur.
The depth of the deposit
Ease or difficulty in accessing the deposit
The flow rate achievable from the deposit: the number of barrels of
oil per day that can be extracted.
How much gas is associated with the deposit and the type of gas
Ease of getting the oil to a refinery
How much of the total oil in the ground can eventually be extracted.

The amount of oil that can be extracted is heavily reliant on the technology used to extract it. With the introduction and use of technologies not previously available more oil might be able to be extracted from the deposit, or oil from deposits not previous considered for extraction could be converted to reserve status and become available to be extracted. When this happens the hydrocarbon resources have become extended.
Similarly, new technology might make oil in different types of deposits capable of being extracted. This is what happened with oil shale deposits when fracking was developing. Until then oil shale deposit were largely untouched.
By being able to extract oil from such new sources also extends the hydrocarbon resource.


Why is a future increase in solar luminosity by 10% supposed to have disastrous consequences for life on earth when the last 30% did not? One remarkable thing about the climate history of earth is that despite the fact that solar luminosity was fully 30% lower in the beginning, temperatures were actually quite close to today. Since then temperatures have stayed in a relatively narrow range, allowing life to develop. This lets one conclude that there are dampening mechanisms in the earths climate system.

But predictions for the next few 100 millions of years are unequivocal that the about 10% increase of solar illumination will massively increase temperatures on earth, leading to annihilation of at least all higher life (For details, see for instance here: Solar_evolution, When will Earth lose its oceans?)

Now, it stands to reason that at some point the climate dampening mechanisms will be overwhelmed by additional solar irradiation. But there is no indication that the next 10% will be it, if at all the last 500 million years seem to indicate a trend to cooler temperatures:

What are the assumptions that these models are based on to come to their dire predictions?

In this regard you can think that the Earth system is like a house with heating but no Air conditioning. Therefore, it has a powerful mechanism to stay warm when the solar illumination is weak (greenhouse effect), but it has no such powerful mechanism to cool down if the solar illumination is too strong.

In hour analogy, let's say you have used your heating to keep your house nice and warm at 22°C over winter, when outside temperatures were much colder than that. As the temperature outside goes up in the spring, you turn down the power of your heating, so to keep the house at 22°C. Now, a ~10% increase in solar power output would be equivalent to the point were the outside temperature surpasses 22°C. Therefore, even with the heating off, your house temperature will start to rise over 22°C for first time, an you can't do anything about it.

The heating mechanism of Earth the greenhouse effect, specially the one due to ${CO}_2$. But most important, is the thermostat that have kept Earth's temperature in the range of liquid water. This thermostat is based on the fact that an increase of temperature leads to and increase of silicate weathering, that in turn leads to a drop in atmospheric ${CO}_2$ concentrations, and therefore to a drop in temperature. This negative feedback counteracts any warming due to increases in solar irradiation.

However, that trick will work only until the point when there is no more ${CO}_2$ in the atmosphere. Then, any increase in solar irradiation will have a direct effect on temperature, and other amplifying feedback will kick in. In particular the greenhouse effect of water vapor: The higher the temperature, the most water vapour in the atmosphere. And water vapor is a very effective greenhouse gas, therefore, that will lead to further increases in temperature.

The following figure gives an idea of the different radiative forcings as calculated by the IPCC AR5:

However, those are relative to the year 1750. The total effect of green house gasses is about 155 W/m². That corresponds to a 45% of the total energy we receive from the Sun (340 W/m²). That would mean that if you take away all greenhouse gases you can counteract an increase of about 45% of solar power output. In other words, Earth can keep turning the heating down to keep the planet temperature stable as the Sun keeps increasing its power output. However, this calculation is very naive, because we can't remove all greenhouse gases (that would mean removing all the water too). The models you mention are more realistic in this sense and they suggest that the critical points is just a 10% of solar output increase, much closer than the 45% of my ultra-simplistic calculation above.

Said that, the references in that Wikipedia article doesn't seem to use models fully coupled with all the Earth's systems involved (carbon cycle, tectonics, methane, albedo feedback, etc.). Therefore, I would took that 10% value with a lot of caution. However, what is true is that at some point, if you increase solar power enough, the temperature controlling processes of our planet will be overwhelmed, and life on Earth's will face the bigger challenge ever for its subsistence.


How different is the proportion of heavy water ($\ce{^2H2O}$) in the different oceans? The average proportion of naturally occurring semi-heavy water or deuterated water, $\ce{^2HHO}$ or $\ce{HDO}$, is about 1 molecule in 3200. The proportion comes from the fact that one hydrogen in 6400 is in the form of deuterium. The heavy water, $\ce{D2O}$, proportion is about 1 molecule in 41 million ($\ce{6400^2}$) as part of a dynamic equilibrium between normal water, semi-heavy and heavy water (water containing 50% H and 50% D, is in fact a balance between 25% of $\ce{H2O}$ and $\ce{D2O}$ and the rest is $\ce{HDO}$).
I understand that the Vienna Standard Mean Ocean Water (VSMOW) has a set proportion equal to the average proportion, but heavy water abundance changes slightly from one kind of water to another.

My question is how much does it change? What oceans have a higher proportion of heavy water? As a hydrogen bond with deuterium is stronger than a normal one, would we expect any biological effects from the different abundances?

For detailed information, see Isotopes of the Earth's Hydrosphere, especially chapter 3 which is "Isotopic Composition of Ocean Water".

At the surface, deuterium fraction is maximized in regions of high evaporation, and minimized in areas with ice.

In the deep ocean, there is about 2% above average deuterium in arctic, and 2% below average near Antarctica.  There is a general increasing trend from south to north.


Best sources / methods to find additional cloud information for current weather conditions? I posted this question on Aviation Stack Exchange here.  One of the responses suggested that I post my question on Earth Science Stack Exchange.

  I need a source that reports necessary current cloud data to determine
  cloud height or cloud type (Cirrus, Stratus, Cumulus, etc.).  I do not need historical data and, for now, I do not need forecast data.  Current data only.

I found a question/answer for determining the bottom of the cloud but I can't find it again.  I found some relative information in Aviation Stack Exchange and one answer here that tells how to find the cloud tops but I'm posting this question anyway in case there is resource yet to be suggested.  I'm giving up on the idea of an API but still hopeful that there are some resources and techniques we can use to acquire this information.

BTW:  I am not a weather specialist.  I am a Software Engineer and we need this information for Ballistic Missile accuracy.  We need to know the weather conditions but cloud data is the most important and yet missing piece.

The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite provides new insight into the role that clouds and atmospheric aerosols (airborne particles) play in regulating Earth's weather, climate, and air quality.

CALIPSO combines an active lidar instrument with passive infrared and visible imagers to probe the vertical structure and properties of thin clouds and aerosols over the globe.

The data from the satellite can be found here (https://eosweb.larc.nasa.gov/project/calipso/calipso_table), from what I see, the latest dataset is about a week old. While this won't give you the cloud type, it will surely give you the cloud heights, you will have to apply some knowledge though to differentiate between clouds and aerosols.

For the cloud type, I suggest you can look at visible satellite data or infrared satellite data to look at clouds and judge the cloud type.

This is the e-wall from Penn State,
http://mp1.met.psu.edu/~fxg1/ewall.html
If you look at the left panel about mid-page, you see the heading 'Satellite' and you can look at the visible and infrared spectrum and also a water vapor satellite image.

This approach seems very raw, but this is what I could remember off the top of my head. I don't know of a page that provides real time data about cloud height and cloud type.


Some website or institute with integrated statistics on forecasting the occurrence of rainbows I am a lay person in meteorology, maybe this is not the right place for my question, but I would like to ask then.
My question is simple: is there a website or institute that has integrated statistics on forecasting the occurrence of rainbows in different countries around the world?

A rainbow is not a physical object that has a position.  It is an optical phenomena that depends on your location relative to the sun and rain.  If you are standing where your eyes can intercept the colored light, you are standing with your back to the sun and the sunlight is reflecting on raindrops in front of you.  Someone else standing in a different location would not necessarily see a rainbow if they looked towards the same location.
From University of Illinois:

According to Descartes' calculations using laws of optics, the three stage refraction-reflection-refraction pattern that light undergoes when passing through a raindrop produces a concentration of outgoing rays along a line that is 42 degrees above the head of an observer's shadow. This concentration of light rays is the rainbow that we see.

Also this National Geographic article has a nice description:

Viewers on the ground can only see the light reflected by raindrops above the horizon. Because each person's horizon is a little different, no one actually sees a full rainbow from the ground. In fact, no one sees the same rainbow—each person has a different antisolar point, each person has a different horizon. Someone who appears below or near the "end" of a rainbow to one viewer will see another rainbow, extending from his or her own horizon.

What this means is that a rainbow is not really a meteorological occurrence that can be measured or catalogued, because you would get a different answer depending on your reference point.  Lightning, in contrast, is a physical phenomena that has a precise location which can be determined and verified from multiple points of reference.
Rainbows are photographed and archived by enthusiasts, but it's really about artistic appreciation.
How Rainbows Happen has a nice description:


How to calculate 'real-world' geometric height from ERA reanalysis data This seems like a really simple question, but I have been struggling for a couple of days to find an answer online or in the ERA documentation.

I am using ERA5 and ERA Interim reanalyses to get atmospheric profiles for a model I am running.
However, the model requires values to be given at fixed values of altitude (above sea level) (it is a rectangular grid 60x60x60 km).

The data I get from ERA (downloaded using the python script API they suggest) gives me data on either pressure level or model level. I can get geopotential as a variable, but there is no option for 'real-world' height.

So my question is how do I calculate the 'real' altitude of each level?

I initially tried dividing geopotential by 9.81, but I'm not sure that's quite right, as geopotential is an integral of g.
Alternatively should I be using the values in the tables here, and if so why are they not provided as an option of a variable or coordinate when downloading the data?

Apologies in advance if this is a silly question with a simple answer and thanks for your help.

If I understood the question right:
CDO can interpolate from model level to height level with the operator

ml2hl infile.nc outfile.nc

additionally, for the lower atmospheric levels, you can add an extrapolation option.
BUT I don't recommend it since its extrapolation performance is questionable.


What does the term spreading the risk mean, with regard to natural disasters? What does the phrase "spreading the risk" mean with regards to risk assessment of natural hazards/disasters?

I came across the phrase in the World Economic Forum document, A vision for managing natural disaster risk. A quote from the document:

  There are various options for risk management – avoidance, reduction,
  transfer or retention. Risk transfer is the underlying tenet for insurance
  markets, passing a liability onto another party (spreading the risk). Risk pooling is vital to the recovery of individuals, firms and economies following a natural disaster.

More specifically, what does the phrase mean with regards to insurance and aid, to reduce vulnerability to a disaster/hazard event?

Insurance may be the best example.

As the document you linked to describes in some detail, there are lots of ways of spreading risk. Traditional insurance is one common mechanism. I think their point is that with a functional insurance model, the effects of a natural disaster may be less profound and/or less protracted (see page 27 of the report).

Think of risk as the possibility of something unpleasant happening — say, something resulting in a financial cost. For example, there's a small risk of a hurricane destroying my house. I couldn't afford to rebuild it if that happened. So I buy indemnity cover for some small fixed monthly fee. Now there is essentially no risk to me, just a small definite cost. In effect, I have transferred my risk to the insurer.

The risk hasn't gone away. In exchange for my monthly fee, or premium, the insurer has assumed the risk of having to pay me a lot of money at some point in the future. It has been pooled with lots of other people — the insurer's other clients — so there's also the grave risk of everyone claiming at the same time. Weighing these risks and setting the premiums accordingly is what insurance companies have to be really good at. Read up on the insurance consequences of the San Francisco earthquake, the September 11 attacks, or Hurricane Andrew.


How long does it take for the atmosphere to mix? If I release a say, one litre of gas, at a particular point on the planet, how soon, on average, would it take to be distributed evenly (mixed) across the entire earth's atmosphere?

The time scale of interhemispheric tropospheric transport is in the order of one year (Chapter 4 of the book Introduction to Atmospheric Chemistry written by Daniel J Jacob). This is not an exact answer to your question, but might be a fair enough number for the problem you have in mind.


Does the shear modulus of silicate minerals vary significantly with changes in P and T? I know that the bulk modulus, K, varies with pressure and temperature for silicate minerals and liquids, but what about the shear modulus? If so, is the change drastic for changes from standard temperature and pressure to mantle conditions?

A quick Google Scholar search for the most studied mantle mineral leads to this paper, with this in the abstract:

  The shear elastic moduli exhibit non-linear pressure dependencies.

So the answer is yes. As for the magnitude and drastic changes, you will have to do some reading.


Cooling film area to undo global warming It is estimated that only 100 square miles of solar panels could completely satisfy the United States demand for energy.

This got me thinking: A cooling film developed at UC Boulder claims it can eject 93 W/m2 into space under direct sunshine, whereas the sun puts 1120 W/m2 onto the earth.

The cooling power of the film is a significant fraction of the total irradiance of the sun. So how many square kilometers of cooling film would be required to return temperatures to (say) 1950 levels assuming current CO2 levels?

I will answer the question with some simplifying assumptions that might then provide a coarse guess of the area needed. First lets assume that temperatures have risen $1^{o}C$ and that the cooling film acts as increasing surface albedo effectively reflecting that an additional fraction of sunlight (93/1366) from earth. By following the footsteps of the idealized greenhouse model we can derive the surface temperature as:
$$T_{s} = \bigg(\frac{S_{0}(1 - \alpha_{p})}{4 \sigma (1 - \frac{\epsilon}{2})}\bigg)^{1/4}$$
Where $T{_s}$ is surface temperature, $S_{0}$ is the solar constant ($1366W/m^ 2$), $\alpha_{p}$ is the planetary albedo, $\sigma$ is the Stefan Boltzmann constant and $\epsilon$ is the emissivity. By approximating the planetary albedo as 0.3 and emissivity as 0.78 we get that the surface temperature of is 288K. We can now set that the surface temperature is one degree smaller and there is an addition to the planetary albedo due to the cooling films. Solving for albedo:
$$\alpha_{p} = -\bigg(\frac{T_{s}^{4}4\sigma (1-\frac{\epsilon}{2})}{S_{0}} - 1\bigg)$$
By substituting the values we find that planetary albedo has to be about 0.31, so cooling of one degree has been reached by a 0.01 additional albedo. The ratio of the cooling film absorbency and solar constant $\frac{93}{1366} \approx 0.07$ can be seen as the additional planetary albedo if the cooling film is installed globally. This being seven times the needed change of albedo implies that a seventh of earths surface should be covered.

This doesn't take into account any secondary effects, that all areas of earth aren't equally important, that earths albedo isn't constant, nor is the emissivity, angle of radiation matters, this equation doesn't really take into account greenhouse effect(it just uses values that provides in current state case reasonable numbers), et cetera. More accurate answer would come by running a climate model and tweaking albedo in fixed grid cells.


How accurate is the law of superposition? Recently I started being more interested in the rational details of the sciences (... being often challenged about them by a creationist friend) and one of the creationist 'theories' I've encountered is how the law of superposition - i.e. the claim that layers of rocks form with the top layer being younger than the bottom - can be falsified. They mentioned some creationist experiments where layers formed 'sideways' and used it as one of the arguments to 'prove' that Earth does not have to be millions of years old.

Now I do not want to engage in a theological discussion, but I was wondering how accurate law of superposition is. Most articles I've read refer to it as an axiom of geology - i.e. something that is assumed, rather than proved. At the same time I am aware of the fact that it's a "first level big picture axiom", in that everyone is aware of the fact that under special circumstances the details get a bit foggy, but looking at the whole world it is correct "often enough" to warrant making it an axiom to simplify the theory for beginning geologists.

Thus my question is: In the global scope, how significant are the deviations from law of superposition in the structure of Earth's strata? Would you say less than 1% of the world show any significant deviation from the law?

I apologise for any jargon misunderstandings I may have committed.

The principle does not apply to all materials on earth as observed by us but is primarily concerned with sediments and rocks that form from sediments. Since sedimentation is a process driven by gravity grains settle one on top of others and there is no possibility to change that without adding additional processes. So from this perspective the principle is 100% in situations where it is applicable.

It is of course not uncommon to find situations where older material overlays younger. In such cases there has been additional forces (natural mind you) in action. It is for example possible for intrusions (magma) to be injected in older solid rocks thus completely changing the age sequence. It is also possible for crustal movement (tectonics) to fold the bedrock and thrust parts of the bedrock to overlay other parts hence creating situations where younger rocks seem to undelie older. It is also possible for sediments to slide or move downslope so that a reverse or at least disturbed age sequence is established. I could continue ad infinitum.

So many possibilities exist to obtain such cases but always with a logical explanation involving post-sedimentary processes. To correctly interprete observations, one has to have gained full understanding of the geological setting and history as well as physical processes. It is not generally wise to look at an outcrop or cut and create a larger scale interpretation without such background knowledge.


Why does Australia have no chrome? I've been trying to collect resource data about Australia for a few years. Some good reference sites are AustraliaMinerals.gov.au and AustralianMinesAtlas.gov.au

Australia seems to be pretty rich in minerals, including iron, copper, nickel, gold, titanium, uranium, and I think lithium and Rare-Earth elements too. But one thing I have never found is chromium. Chrome is essential in the steel industry.

So I'd like to know why. What geological features does Australia lack that make it lacking in chrome? Or do geologists believe that there's a realistic chance that a good chrome deposit is hidden somewhere? And where could that be?

There has only been one chromium mine in Australia - the Coobina mine, in the Pilbara region of Western Australia. It is located 80 km south east Newman (23 deg 29' 31" south, 120 deg 16' 32" east). The resource at Coobina is 1.5 Mt @ 29.4% Cr.

  The ore deposit was discovered in 1924 and was once worked under the names of Jimblebah and Murramunda. It was mined as a series of small open cuts for several decades with most of the pits being less than 70 metres deep.

The deposit is associated with an ultramafic unit.

  Chromite deposits in this rock occurs as massive chromite with up to 150 lenses having been mapped so far. The largest around 340 metres long and 6 metres wide.

Chromium clinochlore is mined at Coobina/Jimblebah.

Other deposits of chromite occur at Mount Christie, Tomkinson Ranges and Wingella Hills, in South Australia.

Mount Christie is within the Gawler craton and Tomkinson Ranges and Wingella Hills are within the Musgrave block.

At Moount Christie,

  The best intersection was 1.5 m at 9.8% Cr2O3. Microprobe analysis showed the chromite to contain ~48% Cr2O3 and 30% FeO, which may only be suitable as chemical-grade chromite.

  Chromite has been identified within Mesoproterozoic Giles Complex rocks in the far northwest of the State. It occurs as rare veins up to 10 mm thick within layers of pyroxenite in the Tomkinson Ranges (Coats, 1956) and as grains in ultrabasic rocks of the Wingelinna Hills intrusions. A representative sample gave an assay of 16.9% Cr2O3.

Geoscience Australia has very little information about Coobina.

Some more information from Geoscience World and Research Gate.


How do seismologists locate the epicenter and focus of an earthquake? I know the focus of an earthquake is where the earthquake originated from, but what I could never figure out is, how to scientists find out where exactly the focus (and epicenter) are located?

Earthquake epicenters are located using triangulation, this is possible once seismograms of the earthquake - coming from at least three locations - have been analyzed properly. Here is a good explanation on a site for seismology students at Michigan Tech which takes its seismogram illustrations from Bolt's textbook on earthquakes (1978). Read this page and you will have a good explanation of how seismologists determine the location of an earthquake epicenter.

How Do I Locate That Earthquake's Epicenter?


Earthquakes in Oklahoma influenced by Humans? I'm currently living in Oklahoma, and there has been an abnormal amount of earthquakes lately, by abnormal I mean more then 5 in a day(not sure if that's normal or not)..

I've also been told that in OK earthquakes are a relatively new thing, now they've brought a bunch of experts in to try to figure out the problem but my question being what could possibly cause so many earthquakes to start happening randomly?

I have a couple theories:

Oil wells, we're sucking up all the oil in the ground and the planet is trying to cope with it
Underwater waste pipes, idk if these would have anything to do with it, but putting something underground that isn't natural seems like a bad idea to me..

For some insight on what's happening see here see also graph

UPDATE:

There has been 30 earthquakes in the past 21 hours.

30 earthquakes today
76 earthquakes in the past 7 days
196 earthquakes in the past month
2,213 earthquakes in the past year

Taken from Today's Earthquakes

UPDATE 2:

14 earthquakes today
81 earthquakes in the past 7 days
206 earthquakes in the past month
2,222 earthquakes in the past year

September 2016 update

https://www.usgs.gov/news/magnitudes-oklahoma-earthquakes-shift-upward

Does this new development change any of the existing answers?

The sudden and recent occurrence of multiple earthquakes in Oklahoma is due to a widespread redistribution of stresses within the ground, particularly at depth.

Installing large pipes underground for storm water, waste water, or potable water or even digging a basement under every house in an entire city will only cause a very minor localized redistribution of ground stresses, near the Earth's surface. Such minor redistributions of stresses will not lead to earthquakes.

As Blaydes states, injection of fluids and fracking will induce additional stresses and they can also lead to faults and ground fissures becoming lubricated and thus prone to movement, resulting in earthquakes.

Removal of a liquid from an underground reservoir, oil or water, can have an adverse impact. If the reservoir is naturally pressurized, tapping the reservoir will reduce its pressure and the affect that has on the surrounding rock.

Depending on the circumstances, releasing pressure can unlock rock, allowing it to move. It's a bit like having a number of blocks of lumber clamped together by a vice a or a clamp. Provide enough stress (clamping force) and everything is held together nicely. Too much stress and the blocks become damaged due to the strength properties of the individual blocks. Not enough stress and the blocks become free to move relative to one another.

It is well documented, particularly in the US, that removal of water and oil from underground reservoirs can cause surface subsidence. In the case of the Lost Hills and Belridge oil fields in California, subsidence rates of up to 40 mm/day (greater than 400 mm per year) were measured. In the Wilmington oilfield at Long Beach, California, an area 50 square kilometres subsided. In the centre of the subsidence area the maximum subsidence was 9 meters.

The removal of liquids from underground reservoirs results in a reduction of fluid pressure which causes the pore spaces to close and the sediments to compact, resulting in subsidence. As the sediments compact the rock above it also subsides. Under certain circumstances, such ground movements can induce earthquakes.

In Oklahoma's situation, oil pumping, fracking and fluid injection into oil wells are very likely candidates for the causes of earthquakes experienced there.


How much further can weather forecasting models go before the limits of Chaos Theory set in? Refer to a report here that mentions the huge advancement in weather forecasting models since the 1980s:

  How much better? “A modern five-day forecast is as accurate as a
  one-day forecast was in 1980,” says a new paper, published last week
  in the journal Science. “Useful forecasts now reach nine to 10 days
  into the future.”

But weather forecasting cannot be indefinitely accurate, one fundamental limitation is Chaos Theory:

  Chaos: When the present determines the future, but the approximate
  present does not approximately determine the future. (Wikipedia)

I used to think some ten or twenty years ago that the accuracy level of 3 day weather forecasts was due to Chaos Theory, but apparently it wasn't.

Are there studies where weather forecasting models are subjected to sensitivities of initial conditions, investigating how Chaos Theory puts an upper limit on the accuracies of such models? Also, based on current models, how much further can weather forecasting models go before the limits of Chaos Theory set in?

There are (at least) two factors involved here, before we even get to questions of chaos theory.  First, thanks to weather satellites and other sensor improvements,  we can measure the initial conditions much more accurately.  (One can do a halfway decent 3-day forecast for the West Coast just by eyeballing the GOES West images.)

Second, we have greatly increased computing power.  Forecast models (simplisticaly) work by dividing the world, or part of it, into a 3D grid, applying a set of differential equations in the grid, propagating the changes to neighbors, and then stepping forward in time to repeat the process. The finer you can make the grid, the more accurate the forecast can be.  However, if you cut the size of a cell in half, you need to do 8 times as much computing.  And if it takes longer to do your computation than the actual weather, it's not much use as a forecast :-)


In cities, is the pollution level higher on higher floors? Is there a difference between the pollution levels at higher vs lower floors in a high rise building?

Yes, the higher floors will have less pollution than the street level.
The wind rises as a function of altitude, so the street will have less new air coming in, on average:

Some of the pollutants are lighter than air, i.e. Ozone, and some are heavier, i.e. particulate matter, they tend to rise or fall very slowly, so they can be slightly different gradients at different floors of the building.
The pollutants are diffuse clouds that rely on ambient air currents for dispersion.


What data of agricultural yield to use for India? I am trying to understand the role of various meteorological factors on agricultural yield over India. Is there a dataset available directly or an indirect proxy of agricultural data, maybe satellite, if any product is there

In case you cannot access official local data, I recommend the use of the IFPRI resource MapSPAM2010.
Quoting the description of the dataset:

  Using a variety of inputs, IFPRI's Spatial Production Allocation Model (SPAM) uses a cross-entropy approach to make plausible estimates of crop distribution within disaggregated units. Moving the data from coarser units such as countries and sub-national provinces, to finer units such as grid cells, reveals spatial patterns of crop performance, creating a global grid-scape at the confluence between geography and agricultural production systems. Improving spatial understanding of crop production systems allows policymakers and donors to better target agricultural and rural development policies and investments, increasing food security and growth with minimal environmental impacts.

The dataset makes available data about agricultural variables for 42 crops at 10km resolution for the whole world. More info are available in the MapSPAM website, while the full dataset is available here.

Reference: International Food Policy Research Institute, 2019, "Global Spatially-Disaggregated Crop Production Statistics Data for 2010 Version 1.1", https://doi.org/10.7910/DVN/PRFF8V, Harvard Dataverse, V3

You can download the global rasters and then clip the area you are interested in and make your own estimates regarding specific crops and production technologies.

The information in this dataset, would help you to set up a relatively simple crop model, such as the FAO AquaCrop. This system, even with a approximative calibration, could help you to understand some of the impacts of the

  meteorological factors on the agricultural yields.


Kalman - Data assimilation with external model I'm working with a distributed snow model which simulates Snow Depth and Snow Cover area. It takes in input some atmospherics variables : Temperature / Precipitation / Wind speed ...
I want to assimilate the output : Snow Depth retrieving remote sensing data ( I have snow cover indices for each 10 days ) and by using Kalman Filter. But some ambiguities that prevent me to do it :

I implemented equation (2a) and (2b), but I have no idea how to implement the model operator M quoted in equation (3)... If you have any idea or document that describes carefully this operator please provide it to me.

$M$ is the forward model you are using. It is the dynamical model used to solve whatever discrete equation evolves the field ($d?/dt=$).

The best way to start with data assimilation and understand its nomenclature is to read Ide et al. (1997). In their work, they explain it as:

  A discrete model for the evolution of an atmospheric, oceanic, or coupled system from time $t_i$ to time $t_{i+1}$ is governed by an equation

  $x^f(t_{i+1})=M_i[x^f(t_{i})]$,          (1)

  where $x$ and $M$ are the model's state vector and its corresponding dynamic operator, respectively. The state vector $x$ has dimension $n$. The dynamics $M$ of the model evolution (1) in a computer simulation or prediction is commonly nonlinear and deterministic, while the true geofluid might differ from (1) by random or systematic errors.

Ide, K., Courtier, P., Ghil, M., Lorenc, A.C., 1997. Unified notation
for data assimilation: operational, sequential and variational. J.
Met. Soc. Jpn. 75, 181– 189.


WRF vertical integrated moisture flux using NCL Does anyone know how to calculate the vertical integrated moisture flux using NCL in WRF.
It would be best if you can share a NCL script.
Here is my code, I used this code to calculate the averaged moisture flux in a month.
but I am confused the unit of the last output.
Another question is that I am not sure if I need to divide the output by 9.8?

    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  dir1   = "/Users/gerry/Desktop/WRF_EXTPCP/wrftest/"
  FILES1 = systemfunc (" ls " + dir1 + "wrfout_d01_* ")
  a1     = addfiles(FILES1+".nc","r")

;-------calculate total layer vapor flux--------------------------

  psfc        =   wrf_user_getvar(a1,"PSFC",-1)*0.01                    ; surface pressure, turn to hPa (; unit of PSFC in WRF is Pa)
  pres        =   wrf_user_getvar(a1,"pressure",-1)                     ; air pressure  hPa (time,level,lat,lon)
  temp        =   wrf_user_getvar(a1,"tk",-1)                           ; K
  rh          =   wrf_user_getvar(a1,"rh",-1)                           ; %
  ua          =   wrf_user_getvar(a1,"ua",-1)                           ; m s-1
  va          =   wrf_user_getvar(a1,"va",-1)                           ; m s-1
  ; printVarSummary(psfc)                                                 ; (time,lat,lon)
  ; printVarSummary(pres)                                                 ; (time,level,lat,lon)
  ; printVarSummary(temp)                                                 ; (time,level,lat,lon)
  ; printVarSummary(rh)                                                   ; (time,level,lat,lon)
  ; printVarSummary(ua)                                                   ; (time,level,lat,lon)
  ; printVarSummary(va)                                                   ; (time,level,lat,lon)

  psfc1       =   dim_avg_n_Wrap(psfc,0)
  pres1       =   dim_avg_n_Wrap(pres,0)
  temp1       =   dim_avg_n_Wrap(temp,0)
  rh1         =   dim_avg_n_Wrap(rh,0)
  ua1         =   dim_avg_n_Wrap(ua,0)
  va1         =   dim_avg_n_Wrap(va,0)

                                                    ;https://www.ncl.ucar.edu/Document/Functions/Built-in/mixhum_ptrh.shtml
  shum        =   mixhum_ptrh(pres1,temp1,rh1,2)    ;units: (hPA,K,%,kg/kg);calculate the specific humidity(2),(1)means mixing ratio
  printVarSummary(shum)
  uq          =   ua1 * shum                        ;vapor flux
  vq          =   va1 * shum

  copy_VarCoords(psfc(0,:,:), psfc1)
  copy_VarCoords(ua(0,:,:,:), uq)
  copy_VarCoords(va(0,:,:,:), vq)
  copy_VarCoords(pres(0,:,:,:), pres1)

;;--vertical integrated moisture flux
  ptop        =   100                                                                   ; top layer pressure
  pbot        =   1100
  uqflux      =   vibeta(pres1(lat|:,lon|:,lev|:),uq(lat|:,lon|:,lev|:),2,psfc1,pbot,ptop)/9.8    ;should divide 9.8??
  vqflux      =   vibeta(pres1(lat|:,lon|:,lev|:),vq(lat|:,lon|:,lev|:),2,psfc1,pbot,ptop)/9.8
                                                                                ; 1 means linear interpolation, 2 means log interpolation
  qflux       =   sqrt(uqflux^2+vqflux^2)

I am going to explain my answer based on how the authors from this paper calculate this Vertically integrated moisture flux convergence as a predictor of thunderstorms. This is the equation that is defined in their paper

$$ VIMFC = -\frac{1}{g} \int_{700\,hPa}^{1000\,hPa}\ (\frac{\partial u q}{\partial x}+\frac{\partial v q}{\partial y}) * dp $$

For a reference for the vertically integrated moisture flux please look at the equation in the reference A Hydrological Definition of Indian Monsoon Onset and Withdrawal

$$ VIMFT = -\frac{1}{g} \int_{700\,hPa}^{1000\,hPa} (q * u + q * v) * dp$$

So I will provide an algorithm for a numerical implementation of this equation and opinions can vary what exactly constitutes a "atmospheric layer" in NWP.

In this equation q is the specific humidity, u and v are the zonal and meridional velocities, p is the pressure,  g is the acceleration due to gravity.

Moisture flux convergence or divergence is

$$ (\frac{\partial u q}{\partial x}+\frac{\partial v q}{\partial y})$$

Moisture flux is

$$ q * u + q * v  $$

You then need to sum the horizontal moisture flux convergence(or in your case moisture flux) over the following layers
1) 1000 - 925 hPa
2) 925-850 hPa
3) 850-700 hPa
So the definition of what a "layer" is subjective and you can include three pressure surfaces in it if you think a deep layer is required as opposed to a shallow layer. Numerically a layer can be thought as the average values of two pressure surfaces. As an example in your case you take the average of the velocities at the 1000 hPa and 925 hPa surfaces and the average of the specific humidity at the 1000 hPa and 925 hPa.

Once you calculate the horizontal moisture flux(or if you are calculating MFC then you need to use  finite centered differences and backward and forward differences at the grid boundaries and that procedure is explained in this ESSE answer - Moisture flux convergence numerical procedure and here Finite differences for calculating MFC) over each layer you multiply that by dp and then sum up the contributions.

UPDATE

In response to the questions in the comments

$"1000 - 925"$

is not to be interpreted as a subtraction but as an average.

What needs to be done is to take an average of two pressure surfaces in the following manner

$ q_{layer} = (q_{1000} + q_{925})/2$

$ u_{layer} = (u_{1000} + u_{925})/2$

$ v_{layer} = (v_{1000} + v_{925})/2$

Once you do this for every layer multiply by the corresponding value of dp and in this case

$ dp = 1000 -925 $

This is a subtraction. Then you plug the individual values into the sum of individual contributions for each layer and then sum the layers

$ (q_{layer}* u_{layer} + q_{layer}* v_{layer}) * dp$

The units of VIMFC is typically

$$ 10^− 5 \, kg \, m^− 2 \,s^− 1 $$


Cause of Wallace line First off, I am a biologist, not an earth scientist.

Very recently I heard about a very interesting biological phenomenon that has its origins rooted in geology : The Wallace Line.

From a biological perspective, this is very interesting. Wikipedia explains it very, but in short: The Wallace Line describes that in south east Asia there is a very strong divide in occurrence of species when comparing everything from Bali westward, and everything from Lombok eastward. e.g. large mammals characterizing Sumatra and Java are: Tigers, Elephants and Rhinos. Whereas eastward of the Wallace Line, you have your Marsupials. The same goes for many other different animal and plant species.

Explanation given is that many many many years ago when the sea level was much lower, there was an oceanic divide between east and west of south east Asia. This is supposed to be the result of tectonic movement. However, I have not been able to find a detailed explanation what could have caused this deeper oceanic divide. If I look at maps of tectonic plates and tectonic activity in the region, there are no tectonic boundaries that overlap the Wallace line.

So all this leading to my question: What could have been the cause of the this deep divide?

Here a link of the Wallace Line

Here a link of Indonesian Bathymetry

So all this leading to my question: What could have been the cause of
  the this deep divide?

Think about what animals need to travel between Islands.  It's very difficult unless the water between the islands either drops or freezes over (Deer, for example, have crossed from New Jersey to Staten Island when the Hudson River freezes over), but the ocean doesn't freeze near the Wallace line.

Or, during ice ages when sea level falls as much as 410 feet, Islands can be joined as sea level drops.   Japan, for example, a land-bridge formed through Hokaido to mainland Asia.  Likewise, the UK connects to France and the Bering Straight becomes land as well.

There's nothing particularly remarkable about the water over the Wallace line other than it being too deep for any land bridges to form during ice ages.  The relevant geological feature for land bridges is shallow oceans/seas/bays/straights/channels, etc.   The Java sea is sufficiently shallow that all the islands Northwest of the Wallace line are joined when sea level falls.

It was pointed out that it's rough water too, but that's not the primary reason.   The primary reason is simply the ocean's depth and width.  Animals have little incentive to try to cross any fairly large body of ocean.  Animals sometimes migrate across raging rivers, but in that situation the other side is clearly visible.  The islands on each side of the Wallace line, even with the sea level drop, would (I assume), appear very far away to the eye, if they could be seen at all.


What are the impacts of sublimation on an annual mountain snowpack? Massive amounts of freshwater rests atop the world's mountains in the form of ice, snow, permafrost, and glaciers.  Many areas of the world rely upon the melting of snow and ice to recharge their rivers and reservoirs.  But not all of that ice and snow actually melts. Some percentage of a snowpack will phase change directly into water vapor (sublimation).

How much potential mountain run off is lost to sublimation anually?  How can we measure this loss?

What sort of insight do researchers have on the impacts of sublimation on the local microclimate?

I looked into this and found Sublimation from a seasonal snowpack at a continental, mid-latitude apline site by Eran Hood, Mark Williams, and Don Cline go into great detail on this subject.

Martinelli (1960) reports that sublimation is
responsible for only 1-2% of summer snowpack ablation in snowfields between 3500-3800 m in the Rocky
Mountains.
(West and Knoerr, 1959) Measurements from snow evaporation pans at the Central Sierra Snow Laboratory in
California measured annual sublimation at only 25-35 mm or 2-3% of total ablation over the snow season
Beaty (1975) reported that sublimation was responsible for 80%
of the ablation of fresh snow and 60% of the ablation of older snow during springtime conditions in the
White Mountains of California.
Kattelmann and Elder
(1991) estimated sublimation from snow to be 18% of total precipitation over two water years based on data
collected in the Emerald Lake Basin in the Sierra Nevada.
Marks and Dozier snowpack estimated lost to sublimation in the Sierra Nevada to be
20%.
Water losses to sublimation were equal to 13% of annual
precipitation at Niwot Ridge.
Hood, Willians & Cline report 15% of maximum snow accumulation at the study site was lost due to sublimation.
Another article notes the importance of vegetation on sublimation:   ranging from 13% for a mixed spruce–aspen, 31% for the mature pine and 40% for a mature spruce stand. The results indicate that sublimation can be a significant abstraction of water from mature evergreen stands in northern forests.

The results seem somewhat inconclusive.  This topic needs more comprehensive and robust research.

Take-aways

15-20% is the range given by the most recent studies in the intermountain USA.
Solar
radiation was the most closely correlated with trends in sublimation and condensation.
Vegetation impacts sublimation rates.


Monsoonal interactions with mid latitude disturbances For the past few years in succession India has witnessed extreme flooding events caused by monsoonal troughs colloding with what appears transitory mid latitude disturbances and these appear to trigger flash floods. Case in point - http://en.wikipedia.org/wiki/2013_North_India_floods and http://en.wikipedia.org/wiki/2014_India%E2%80%93Pakistan_floods. My question relates to the physics of such interactions.

Following are my questions:
1) The northward propagating waves emanating at the 850 hPa level from the MJO(BSISO) appear to be damped at the Himalayan foothills(30 N latitude). Following orographic interactions I presume the 850 hpA 's geopotential height appears to be raised. Is that an accurate statement i.e. in the mountains the 850 hPa monsoonal trough's geopotential height is higher(much higher) than at sea levels?

2) Then the planetary wave at the 500 hPa level then appears to be dipping down in the tropics and interacting with monsoonal troughs. How does a upper level trough "propagate" down ? Is this due to quasi geostropic theory?

Here are two parts of an answer, but this is by no means complete.

Most monsoonal research is focused on explaining the monsoonal passage through the plains of the Indian subcontinent. Very few papers can be found on how the same troughs cause rainfall at 3000 meters. I would like an authoritative reference on Monsoonal Mountain Meteorlogy. All that is known is that the MJO (BSISO) troughs and ridges at the 850 hPa seem to be damped at the Himalayan foothills.
Regarding the 500 hPa propagating downwards I cannot get further more information than introducing the concept of a downward propagating Rossby wave.
And as  far as the physics that explains what happens when these two disparate systems meet it is at best an open research topic.
I have read recent discussions(no reference available yet) that the two systems may need to "line up" in other words the geometric center of the upper level system needs to pass through the center of the lower level trough.Very recently Tropical Cyclone Hudhud moved up northwards towards the Himalayas and caused a blizzard in Nepal. There was a corresponding mid latitude disturabance at around the same time over the western Himalayas but extraordinary damage was prevented because the two systems did not line up.

What is of more serious concern is the fact that there have been four such incidents in recent times - 1) Pakistan Floods 2010 2) North Indian Floods 2013. 3) Indian Pakistan floods of 2014. 4) The near miss with Cyclone Hudhud.
What climatic changes are causing  these collisions between disparate systems is a new field of study. Both weather and climate models will be stretched to predict these sort of collisions.


Would there still be wind if Earth had no water? If there was no water on the earth would there still be wind? If the planet was basically a desert from pole to pole, east to west, would the wind still blow? I understand that wind is a result of a difference in pressure, but is it true that water being naturally cooler is what creates that pressure difference?

I don't find any answers that clearly state whether or not wind would still exist without water and whether or not water is the originating source of wind. I see that most of the answers that talk about the source of wind say that cooler air moves in as warmer air rises, but wouldn't all the air in the world be warm/hot without water to cool it?  The pressure difference seems to be cool versus warm.

I wouldn't say water is naturally cooler than air.  What I would say is that water has a higher heat capacity than air.  This means it takes more energy to affect the same increase in temperature and conversely it takes water longer to cool down than air.  You can see this at night near bodies of water when the sea breeze changes to a land breeze as the land becomes cooler than the water - water temperatures tend to be stable across diurnal cycles.

I would also contest the statement that water cools the air.  Water does both heating and cooling.  When water evaporates into air, the air cools.  However take a look at any thunderstorm you see -- that is water causing heating as it condenses and freezes.  Water on the surface can also contribute to both heating and cooling.  During the day the cool water surface will have a heat flux that cools the air while at night the opposite may be true.  This depends on the air temperature and the SST.

Now on to your question, yes, there would still be wind if there were no water.  The energy that drives the wind is differential solar heating at the earths surface.  Variations in the surface topography and the shape of the earth mean that the solar flux isn't constant across the earth.  As long as we have a sun we will have surface pressure differences and wind.  Without water we would also see a stronger equator-to-pole temperature gradient (look at temperature variations right now on continents versus open ocean).  This would result in stronger winds that we see today.


Would the enthalpy of fusion for melting ice fields be a causative factor for colder winter weather? Would the enthalpy of fusion for melting ice fields be a causative factor for colder winter weather?

As an example, NASA estimated the annual loss of the Greenland ice field 2002-2013 as more than 280 gigatons, and apparently increasing.  Would the energy required for state transition on such a scale be a causitve factor in colder weather during a period of warming climate?

UPDATED:  My wording above was too generalized and I got good answers to a question slightly different than the one I intended.  Retry:
According to Wikipedia, one of the vortices of the northern Polar vortex is Baffin Island, very near Greenland.  The recent unusually cold weather in the eastern US has been attributed to the path of the Polar Vortex this year. My question should have been "could the energy required for state transition of the Greenland ice field contributed to the change in path of the Northern Polar Vortex this year?"

Would the enthalpy of fusion for melting ice fields be a causative factor for colder winter weather?

No, for a number of reasons.

Ice sheets melt in the summer and rebuild in the winter. This is winter.
The enthalpy of fusion for water is 333.55 joules per gram. Multiply that by 280 gigatons per year and you get 9.3×1016 joules per year. While that sounds like a lot, it's a blip compared to the 5.5×1024 joules the Earth receives from the Sun every year.
It's not a cold winter. While it has been an abnormally cold winter for the eastern parts of the U.S. and Canada, the rest of the northern hemisphere has been rather balmy. Nuuk, Greenland, for example, is suffering a heat wave. The current (06:38 UTC 21 January 2018) temperature there is 3°C (37° F), significantly warmer than average. The normal high for that location at this time of year is -6°C (24° F).

The melting of all that ice might well have an impact on climate, but it's the influx of 280 gigatons (and rising) of fresh water every year into the northern ocean rather than a paltry absorption of 1017 joules of energy every year that will be the cause.


How do weather models work? We use different weather models all the time, such as the ECMWF and the GFS. These models are simply amazing to me.

How do these models work? I know they have to take in various data points - what are these, and how does the model use it? Also, how do they come up with a forecast or a map of what will happen in the future?

All numerical atmospheric models are built around calculations derived from primitive equations that describe atmospheric flow. Vilhelm Bjerknes discovered the relationships and thereby became the father of numerical weather prediction. Conceptually, the equations can be thought of as describing how a parcel of air would move in relationship to its surroundings. For instance, we learn at a young age that hot air rises. The hydrostatic vertical momentum equation explains why and quantifies under what condictions hot air would stop rising. (As the air rises it expands and cools until it reaches hydrostatic equilibrium.) The other equations consider other types of motion and heat transfer.

Unfortunately, the equations are nonlinear, which means that you can't simply plug in a few numbers and get useful results. Instead, weather models are simulations which divide the atmosphere into three-dimensional grids and calculate how matter and energy will flow from one cube of space into another during discrete time increments. Actual atmospheric flow is continuous, not discrete, so by necessity the models are approximations. Different models make different approximations appropriate to their specific purpose.

Numerical models have been improving over time for several reasons:

More and better input data,
Tighter grids, and
Better approximations.

Increasing computational power has allowed models to use smaller grid boxes. However, the number of computations increases exponentially with the number of boxes and the process suffers diminishing returns. On the input end of things, more and better sensors improve the accuracy of the initial conditions of the model. Synoptic scale and mesoscale models take input from General Circulation Models, which helps set reasonable intial conditions. On the output end, Model Output Statistics do a remarkable job of estimating local weather by comparing the current model state with historical data of times when the model showed similar results.  Finally, ensemble models take the output of several models as input and produce a range of possibly outcomes.


Take all the CO2 in the atmosphere and put it into a layer on the surface of earth, how thick would the layer be? I teach a Middle School (year 8) Geometry course and have a student attempting to answer this question. My assumptions:

earth's radius is $3959 \text{ mi}$
earth is a sphere
There is approximately $3 \cdot 10^{15}$ kg of CO2 in earth's atmosphere
The density of CO2 at 1atm is $\dfrac{1562 \text{ kg}}{\text{cubic meter}}$
Conversion between cu meters and cu ft are $1:35.3147$. And cu ft to cu mi is $5280^3:1$

So, first, with assumption (3 and 4) we can compute the volume of CO2 in the atmosphere to be $\approx 1.92 \cdot 10^{12} \text{ m}^3$ or about $369 \text{ cu mi}$ of CO2.

So, now we can find the thickness of the layer by solving the equation

$\begin{align*}
369 &= \dfrac{4 \pi \cdot (3959 + x)^3}{3} - \dfrac{4 \pi (3959)^3}{3} \\
\end{align*}$

Where $x$ is the thickness of the layer of CO2 on earth's surface in miles.

$\begin{align*}
369 \cdot \dfrac{3}{4 \pi} &= (3959+x)^3 - (3959)^3 \\[.5pc]
369 \cdot \dfrac{3}{4 \pi}+3959^3 &= (3959+x)^3 \\[.5pc]
\sqrt[3]{369 \cdot \dfrac{3}{4 \pi}+3959^3} &= 3959 + x \\[.5pc]
3959.0000018746 &\approx 3959 + x \\[.5pc]
.00000018746 &\approx x
\end{align*}$

So, the layer of CO2 on earth's surface would be $\approx 1.87 \cdot 10^{-6} \text{ mi}$ or $.1187 \text{ in}$ in thickness. Which is less than half the thickness of an iPhone 6.

My Question: This result seems incredibly small. Where did I go wrong? Or, is this reasonable. I have no intuition and would be interested in a second opinion!

Ok, based on the comments above, this is where I am at...

earth's radius is $6371 \text{ km}$
earth is a sphere
There is approximately $3 \cdot 10^{15}$ kg of CO2 in earth's atmosphere
The density of CO2 at 1atm is $\dfrac{1.977 \text{ kg}}{\text{ m}^3}$

So, first, with assumption (3 and 4) we can compute the volume of CO2 in the atmosphere to be $\approx 1.52 \cdot 10^{15} \text{ m}^3$ or $1.52 \cdot 10^6 \text{ km}^3$.

So, now we can find the thickness of the layer by solving the equation

$\begin{align*}
1.52 \cdot 10^6 &= \dfrac{4 \pi \cdot (6371 + x)^3}{3} - \dfrac{4 \pi (6371)^3}{3} \\
\end{align*}$

Where $x$ is the thickness of the layer of CO2 on earth's surface in km.

$\begin{align*}
1.52 \cdot 10^6 \text{ km}^3 &= \dfrac{4 \pi \cdot (6371 + x)^3}{3} - \dfrac{4 \pi (6371)^3}{3} \\[.5pc]
\dfrac{3}{4\pi} \cdot 1.52 \cdot 10^6 \text{ km}^3 &= (6371+x)^3 - 6371^3 \\
\dfrac{1.14}{\pi} \cdot 10^6 \text{ km}^3&= (6371+x)^3 - 6371^3 \\
3.63 \cdot 10^5 +6371^3 \text{ km}^3 &= (6371 + x)^3 \\
\sqrt[3]{3.63 \cdot 10^5 +6371^3 \text{ km}^3} &= 6371 + x \\
6371.0029811 \text{ km} &\approx 6371 + x \\
.0029811 \text{ km} &\approx x
\end{align*}$

So, the layer of CO2 on earth's surface would be 2.98 meters thick...


Had the climatologists predicted climate change as the deviations to both extremely cold and hot temperatures before? Recently I read that the current extreme snowfall in northern temperate climate is caused by the increased evaporation due to the global warming.

Had any scientist predicted these extremes before they've been observed?

I've found nothing about such predictions in the Wikipedia article.

The Intergovernmental Panel on Climate Change summarizes the state of scientific understanding of climate change every few years and at least as far back as 2002 has projected a range of changes in extreme weather.

In the IPCC report for 2002, the Working Group II: Impacts, Adaptation and Vulnerability summarized the existing scientific understanding in may areas, including "Climate Variability and Extreme Events":
"Most studies of climate change impacts have focused on changes in mean climate conditions. However, global climate change is likely to bring changes in climate variability and extreme events as well. This is relevant here because decisionmakers often consider hedging strategies to be prepared for the possibility of low-probability but high-consequence events -- a risk management framework.  Features of projected changes in extreme weather and climate events in the 21st century include more frequent heat waves, less frequent cold spells (barring so-called singular events), greater intensity of heavy rainfall events, more frequent midcontinental summer drought, greater intensity of tropical cyclones, and more intense El Nino-Southern Oscillation (ENSO) events." -
Climate Variability and Extreme Events

The question is also addressed in section 2.5. "Projected Changes in Climate Extremes could have Major Consequences":

  The vulnerability of human societies and natural systems to climate
  extremes is demonstrated by the damage, hardship, and death caused by
  events such as droughts, floods, heat waves, avalanches, and
  windstorms. While there are uncertainties attached to estimates of
  such changes, some extreme events are projected to increase in
  frequency and/or severity during the 21st century due to changes in
  the mean and/or variability of climate, so it can be expected that the
  severity of their impacts will also increase in concert with global
  warming (see Figure SPM-2). Conversely, the frequency and magnitude of
  extreme low temperature events, such as cold spells, is projected to
  decrease in the future, with both positive and negative impacts.


Are old geophysics textbooks useful? I have had much success with old textbooks in mathematics. Generally, for any branch of mathematics that I (as a non-mathematician) would like to learn or re-learn, I can buy a classic textbook from the 1970s, and it will be accurate and cheap.

However, as a computer scientist, I know that this is not a great strategy for all subjects.

I am interested in learning more about the geology of the Earth and the other rocky bodies of the solar system. If I buy old editions of textbooks (such as here, here, or here), what am I going to be missing in terms of up to date theory? Am I likely to purchasing a textbook full of no-longer accepted theories or disproven facts?

As a follow up question, if text books like the one from 1979 are too far out of date, how old can I generally go to get an accurate text?

Mathematics and computer science are exact sciences. If something is discovered and known, it is not wrong. With time, there may be better or new ways of doing something, but the old stuff is still correct. This is why you can get a textbook from the 60s and study it. Cauchy's laws are still correct and Euler's theorem is still correct.

This is not the case with earth science (which I expand from your "geophysics"). Just about every paper published in the field of earth science follows the theme of "we thought something but now we found it's actually wrong". And there are hundreds of those per year. While math textbooks teach facts, earth science textbooks present the opinion of the author at the time of writing, which is also commonly the prevailing view in the broader earth science community, but it doesn't have to. In most cases old textbooks are not going to be that bad, but there will be abundant accuracies and omissions. If you go back enough, you might finds that are completely wrong (plate tectonics was only accepted in the 1960s!). But it doesn't have to be this: take subduction zones. The understanding of what happens to slabs once they subduct was only somewhat understood (at least on an undergrad textbook level) in the past 15 years. Whether the slabs themselves melt or not isn't even known today (even though textbooks will mostly say they don't: again, this is the opinion of the author). The inner structure of the earth as understood from seismicity and tomography is being refined every year.

In your textbook links you gave the example of planetary science and volcanism. In the case of planetary science, every time there is a new mission we learn so much. Just example of some discoveries of extraterrestrial volcanoes: Io in 1979, Triton in 1989, and Titan in 2005. Also think of the latest understanding of minor planets, comets and asteroids obtained in the past 5 years. This is not something you will find in even moderately new textbooks.

To sum it up, old earth science textbooks are not completely wrong. But they are wrong to some degree, and they most probably contain a lot of omissions (depends on the exact sub-field). Online sources are usually much better for that. Maybe start with related MOOCs? These can be good starting points. Even if you prefer reading and not watching videos, you can usually find a list of (somewhat) up to date sources there.


How can a tsunami be 'hot'? I am reading about the Samoan tsunami of 2009, in which several independent accounts by survivors said that the wave was 'hot'. They were running for their lives at the time, so were very remiss in failing to actually measure the water temperature. I'm leaning towards the explanation that the water seemed hot because of the adrenaline rush, but before jumping to conclusions, I'm also wondering if (a) there is any other record of a tsunami wave being hot, and (b) could the dissipation of kinetic energy be sufficient to raise the temperature by several degrees? FYI the earthquake that caused the tsunami was a magnitude 7.9, at shallow depth in the Tonga Trench subduction zone, about 300 km away. The wave was up to 16 metres high.

I can't answer part a, but I can help with part b. We first must determine how much kinetic energy, then we can use simple thermodynamics to see how much that could possibly heat up a mass of water.

Kinetic energy calculations are numerically modeled in Dutykh and Dias, 2009. Their largest example uses parameters of a 150km x 50km x 35km fault slipping by 15m at 4 km depth (values in Table 2 of paper). Total energy computed is shown in the graphs below:

Part a. of the table is kinetic energy, and part b. is potential energy. For the earthquake with parameters in Table 2, released kinetic energy is about $3\times10^{14}\text{ J}$, with about the same going into potential energy of the wave. I couldn't find any reliable sources of equating energy release with earthquake magnitude, but according to Wikipedia, $3\times10^{14}\text{ J}$ is equivalent to about a 6.6 earthquake. Take that for what its worth, I was just trying to get a sense of how powerful the earthquake causing the tsunami in question would be.

From here lets see what happens if all that energy (kinetic and potential) is converted to thermal energy. To warm up water noticably, lets say we want a $5\unicode{x2103}$ increase. The specific heat of seawater is $3985 \frac{\text{J}}{\text{kg}\cdot\text{C}}$, and the density is $1025\frac{\text{kg}}{\text{m}^3}$. Therefore the energy released from this tsunami can heat up $$ \frac{6\times10^{14}\text{ J}\cdot 5\unicode{x2103}}{3985 \frac{\text{J}}{\text{kg}\cdot\text{C}}} = 7.5\times10^{11} \text{kg of water} \cdot \frac{1}{1025\frac{\text{kg}}{\text{m}^3}} = 7.3 \times10^{8} \text{m}^3 $$ of water.

The last question is: is this enough? Well, sort of. Since the energy is radiated in all directions, at a distance of 200 km, the tsunami wavefront has a circumference of $2\cdot \pi\cdot200 = 1257 \text{km}$ so each meter of wavefront corresponds to 580 m$^3$ of heated water.

This operates under the assumption that all energy is converted to heat, and that all the tsunami's heat is concentrated in one 580 m$^3$ water slug for ever meter of wavefront at 200 km away. While these assumptions are not perfect, I think a lot depends on the way the wave breaks. If it breaks suddenly (i.e. a suddenly rise from deep water to shallow), you might see a more concentrated conversion of kinetic energy to heat. And 580 m$^3$ is a pretty big mass of water; that would correspond to the heated section of the wavefront being an expanding ring 100m wide and 5.8m deep at 200km distance.

So what I conclude from this thought experiment is that it is plausible that a tsunami from a mid-size earthquake could cause the water hitting the beach to heat up several degrees, given that the wave doesn't travel too far, and that it breaks in the right way (whatever that right way is).

Regarding Samoa, the earthquake at 7.9 put out more energy than we are dealing with here, and Samoa is about 200km from the Tonga trench (though I don't know where in the trench the quake actually took place), so I'll file the hot tsunami theory under plausible.


What is likely to have happened with these newly discovered antarctic volcanos below the ice? The Guardian article Scientists discover 91 volcanoes below Antarctic ice sheet highlights a recently published University of Edinburgh School of Geosciences discovery and cataloging of over ninety new volcanos under the Antarctic ice sheet. A new volcanic province: an inventory of subglacial volcanoes in West Antarctica by Maximillian van Wyk de Vries, Robert G. Bingham and Andrew S. Hein, Geological Society, London, Special Publications, 461, 29 May 2017, https://doi.org/10.1144/SP461.7 note: the article is Open Access!
edit: ...by clicking through the Lyell collection to here: http://sp.lyellcollection.org/content/early/2017/05/26/SP461.7 and then again to view the PDF http://sp.lyellcollection.org/content/early/2017/05/26/SP461.7.full-text.pdf
Below is a screenshot of figure 3, including a cropped subsection. If you open the figure in a new window you can view it at full size. In the subsection there are two rectangles with the word CONE above them. Below these words there are two traces. If I understand correctly, the lower trace is (for lack of better vocabulary) the surface of the Earth, and those cones have been identified as volcanos. However I believe the upper trace is the top of a layer of tephra:.

Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size or emplacement mechanism.1
Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground they remain as tephra unless hot enough to fuse together into pyroclastic rock or tuff.

I'm trying to understand what might have happened here. the two cones are of the order of 10 km apart, and they extend above and below sea level. Was there an eruption below the ice which acted as a buffer and contained the ejecta? With some melting, some water below the ice could help it to flow over time and redistribute more evenly between the cones. Or would these volcanos just blow the ice away completely for an extended period of time and Southern Ocean currents could assist in the redistribution?

Fig. 3. (repeated here in case the original is not easily legible on your device) The upper panel shows an echogram from NASA’s Icebridge mission (NSIDC 2014) that shows generally good agreement between a cone on the echogram and on the Bedmap2 data. The lower panel shows an echogram
from Corr & Vaughan (2008) with basal topography picking out two cones; the dark layer above the bed is tephra believed to have erupted around 2000 years ago.

That's a very interesting study, but only provide very rough information on the posible volcanoes that might exist under the ice.
In the case of the volcanoes shown in the radargram I'll highlight some points that might be the source of your confusion:

The tephra layer that overlay the volcanoes in the radargram was not erupted  by those volcanoes. It was most likely erupted by a volcano from above the ice (subaerial), or a subglacial one far away. It was later buried deep in the ice by the snow falling on top. Otherwise the layers would be much messier in the area and of varying thickness.
If those cone are volcanoes, its shape suggest that they were formed before they became covered in ice. Subglacial eruptions form flat-topped volcanoes with steep sides calles Tuyas, and what is observed are broad shield-type cones, that suggest submarine or subaerial formation.
They don't know if those volcanoes are active, but if one were to start an eruption, wouldn't be of the explosive type, because are likely to have fluid basaltic lavas, like the ones observed in Hawai'i. The explosiveness will come from the steam produced. It is hard to tell if it will blow the ice on top or not. It depends on ice thickness, eruption power, etc. But it is definitely a possibility for a strong enough eruption.


Why does more sunlight hits the equator than the ecliptic path? I've always been told that the equator is the region on Earth that receives the most sunlight.

But I wondered, since the ecliptic is the circular path that the Sun appears to follow over the course of a year, then wouldn't the ecliptic path receive more sunlight than the equator?

The ecliptic path, is a well defined trajectory when displayed on the background of the fix stars like in the following figure

(taken from physics.csbsju.edu)

However, there is not such thing as an ecliptic path on the surface of the Earth. If you thought of it as the "Ground track" of a satellite but applied for the Sun, you have to consider that the rotation of the Earth would make that "ground track" of the Sun look very different than the one on the figure above. It would be a spiral going around the Earth ~365 times at latitudes between the tropics of Cancer and Capricorn (remember that the Sun takes a full year to go trough the ecliptic path).

When the the Sun is at its Northernmost declination (the top point of the red curve above), which is ~23° all the points on Earth at latitude ~23° North (the tropic of Cancer) will receive the maximum possible solar irradiation at the solar noon of that day. Once the Sun moves down to declination 22°, it will be the turn of the points at 22° North and so on.

The reason because the Equator is the line that receive more solar radiation is because it is the one that is in average closer to the Sun's ground track (in other  words, is the place with the maximum mean solar elevation).

An equivalent visualisation would be to take the mean of the ecliptic, and by looking at the above red line is quite straightforward to see that it would be a flat line on the celestial equator, that translates to the Earth's equator.

Does that makes sense to you?