First, read these three very relevant questions and answers:
Why the "Mission to Earth’s core" proposal suggests using liquid iron instead of lead?
Can we really travel through earth's core?
Hypothetically, what would happen to the earth if a large hole was drilled through the center?

It is possible to send a probe deep within the Earth?

No.
Here's why:
First, there is a very common misconception that there's some sort of magma ocean underneath the crust. No - there isn't. The Earth's mantle is overwhelmingly solid rock. There are very small and localised places where you have melting, and that's where you have volcanoes (if it reaches the surface - most often it doesn't).
Second, even if you go to a volcano and drop your probe there, there is no simple tube that goes down. A volcano "plumbing" system is more like a maze with bifurcations, bends, kinks, and all of that. Not only that, you are going against the flow. You've probably seen videos of erupting lava flows (one, two). These things are massive and fast. Your probe will have to go against the flow in that thing. It will be worse than trying to go upstream in river rapids.
Third, even if you somehow manage to make a probe that autonomously navigates upstream in thin underground lava corridors with surprise bends, you have to remember the underground magma chambers are not 100% liquid. They are what we call "crystal mushes", which is a pile of small crystals (i.e., bits of rock) with liquid in between. Think more like wet sand, than pure liquid. So you're not swimming in something with no resistance, you also actively have more solids out of your way.
Fourth, molten rocks are extremely corrosive. You were talking about materials with high melting points. That's not your problem. Even the hottest lavas only get to about 1400 °C. We have relatively cheap materials that will melt at much higher temperatures. The issue is the reaction between the magma and the materials into making new materials, or dissolving completely in the magma. As an illustration, consider sodium chloride. Salt. The point at which it melts, if you stick it into a furnace is around 800 °C. Surely, that's much above the temperature of let's say an ocean, and it might be a good idea to make submarines out of salt! Clearly, bad idea. Because the salt will just dissolve into the ocean. Whether it melts or not is irrelevant. So that's the big problem with your probes - the magma will simply dissolve it.

So to sum up, you need your probe to be able to navigate in the dark and propel itself upstream in magma, be able to dig and clear space up front so it can move forward, and made of a material which is inert to the magma. Sorry - not happening. But a fun thought experiment nonetheless.


Equinoxes and solstices: start of the season or mid-season?

There are three main ways to reckon seasons:

Solar. The 3 months with the greatest insolation are designated summer, so the solstices and equinoxes fall in the middle of the season. In the Celtic calendar, summer started on 1 May; in the traditional Chinese calendar it is 5-7 May. The cultural 'Midsummer' and 'Midwinter' festivals reflect this.
Astronomical. The solstices and equinoxes are the starts of the seasons, with summer starting on about 21 June (it varies). Its use dates back at least to the Romans, and it's used in most western cultures today (apparently not in Russia, Australia, or New Zealand).
Meteorological. This is what professional meteorologists use (e.g. UK Met Office), and is based on the prevailing weather on land at mid-latitudes. Seasons are 3 months long and summer starts on 1 June.

I've tried to illustrate the relationships with insolation and temperature here:

There are some other ways too:

Ecological. Scientists who study the behaviour of organisms (hibernation, blooming, etc.) adapt to the local climate, sometimes using 6 seasons in temperature zones, or only 2 in polar and tropical ones.
Agricultural. This would centre around the growing season and therefore, in North America and Europe at least, around frost.
Cultural. What people think of as 'summer', and what they do outdoors (say), generally seems to line up with local weather patterns. In my own experience, there's no need for these seasons to even be 3 month long; When I lived in Calgary, summer was July and August (hiking), and winter was December to March (skiing). Here's another example of a 6-season system, and a 3-season system, from the Aboriginal people of Australia, all based on weather.

Why do systems with later season starting dates prevail today? Perhaps because at mid-latitudes, the seasonal lag means that the start of seasonal weather is weeks later than the start of the 'insolation' period. In a system with no heat capacity, there would be no lag. In systems with high heat capacity, like the marine environment, the lag may be several months (Ibid.). Here's what the lag looks like in three mid-latitude cities:

The exact same effect happens on a diurnal (daily) basis too — the warmest part of the day is often not midday (or 1 pm in summer). As with the seasons, there are lots of other factors too, but the principle is the same.
These aren't mutually exclusive ways of looking at it — there's clearly lots of overlap here. Cultural notions of season are surely rooted in astronomy, weather, and agriculture.


The Tambora eruption caused the "Year without a summer". How much would such an eruption today affect the output of solar pv on a global scale?

Volcanic eruptions effectively inject large quantities of aerosols in the upper layers of the atmosphere, increasing Earth's albedo and reducing the intensity of the solar radiation reaching the surface. Such reduction would indeed lower the solar energy available to solar panels.

These effects of volcanic eruptions have been studied by Gao et al. (2008) and Crowley and Unterman (2013). Both studies were combined by the IPCC Working Group I during the assessment report 5 (2013), and summarized on the figure 8.18 (Chapter 8), together with other climatic forcings:

You can see that the largest drop in effective radiative forcing happens in 1815 as a consequence of the Tambora eruption.

Unfortunately, that event goes out the scale of the plot. However, the data is available on Table AII.1.2 of Annex II, were we can see that the minimum value indeed happens in 1815 and reaches –11.629 W/m².

Considering the typical amount of energy received from the Sun under clear skies at seal level is roughly 1,000 W/m², the irradiation drop produced by Tambora would represent a drop of about 1% on the energy reaching the Earth's surface. Of course, much larger local effects could be observed due to transient and more localized dense ash clouds.

Therefore, at a global scale, if a new "year without summer" where to happen, photovoltaic energy output would drop by ~1%.

Of course, larger effects would take place if the eruption happens to be close to the most important areas for photovoltaic energy production.


The Mercator Projection has been used and it is used since the XVI century due to it maintain the course, rhumb or route. So it is useful for navigation.

As the Earth is approached by a ellipsoid, then you get the formulas that you saw on Mercator Projection. This transformation it is complicated for a ellipsoid, as the Earth curvature it is not a constant, so in the example you gave (moving 300m eastwords, or 400m northwards), you need to transform the first point from geographical coordinates to rectangular coordinates, then shift the point 300 meters east, check the correction on distance due to the different curvature on each point, apply the correction, then shift the point 400 meters northwards, check the correction, apply the correction and bring the coordinates back to geographical coordinate.

That is to much computing time and there are a lost of precision loss on the different shiftings and transformation geographical <-> rectangular coordinates. Web Mercator is just a Mercator that considers the Earth approach by an sphere, not a ellipsoid. That is much easier, needs less computation as, the curvature in a sphere is constant it is not required to consider.

Mercator projection is ok for navigation (that is what you are doing with Google Earth or Google Maps). Check this link.

Regarding the constants... a is the semi-major axis of an ellipsoid, amap is the semi-major axis on the map (as the Mercator Projection is distorting the distances, you should make a distance correction, that it is become bigger as far as you are from the Equator) e is the eccentricity of the ellipsoid.

Regarding the latitude issue... Thing a little bit on this question: In the Mercator Projection it is consider, as Earth approach a sphere and a revolution ellipsoid. Both surfaces are revolution surfaces so, there is no variation along the longitude way. That is why the longitude is not required for Y calculation.

Anyhow, is something is not clear, just let me know. Hope it helps!


Can I just walk around Greenland with a UV light and find rare Earth minerals on the ground?

I think the answer to your question have to be no.

Lots of minerals are fluorescent in UV light,You can take a look here https://geology.com/articles/fluorescent-minerals/

So as you can see in the linked summary of fluorescent minerals it can be hard to tell what you have found unless you know what to look for.

A better way to find Rare Earth Elements might be to use a Geigercounter,Many of the Rare Earth Elements can be found toghether with radioactive minerals.

Here is an example from Norway https://reeminerals.no/fens-field this is an area not far from where i live.

As you can see in the linked article this area can be seen using detectors from an airplane,Maybe not to tell the composition but it can give a hint about where to look.


Rate of underground formation of carbon-14 by neutron capture

I do not have access to the article you cite for the deep subsurface neutron flux but I question whether either article will be particularly useful. The shallow water and soil article is concerned with neutrons in the atmosphere and these attenuate so won't be significant at depth.

The major neutron source at depth are spontaneous fission of U-238 and α-n reactions from U and Th series alpha decay. So your flux will be highly dependent on the amount of uranium and thorium and the presence of light elements that will undergo the α-n reaction. This means that the flux will likely be very different from the Broken Hill ore deposit. You may want to look at the literature on subsurface Cl-36 production for flux estimates, but I'm unaware of any dealing with coal deposits.

In coal the C-14 production will be dominated by neutron capture on C-13. Nitrogen n-p should be insignificant because of it's low abundance. I think the n-p reaction depends on higher energy neutrons produced in the atmosphere (but check that).

Assuming you know or can bound the neutron flux then you can estimate the C-14 from the neutron capture cross section of C-13 - 1.4 mb (Chart of the nuclides 16th ed) and the half life of C-14 - 5715 years, assuming steady-state.


Why does phosphate rock contain uranium?

To understand why sedimentary phosphate rocks (hereafter referred to as phosphorites) have elevated uranium contents we first need to understand what are they made of and why do they form in the first place.

Phosphorites are rocks that are made of apatite, a mineral with the formula $\ce{Ca5(PO4)3(F,Cl,OH)}$. This mineral (especially the OH variant) is one of the main constituents of skeletons of living organisms. The hard mineralised part of your teeth and bones are made of apatite, for instance.

Skeletons of dead marine animals (e.g. fish) are deposited on the ocean floor as apatite. The source of apatite need not be biogenic: it can also be sourced from igneous or hydrothermal activity occurring on the ocean floor, or derived as clastic material from the continents. The end result, is the deposition of apatite as phosphorites.

An important property of apatite is that it can accommodate some uranium. The mechanism is not yet completely understood, but it's most likely the incorporation of $\ce{U^4+}$ in the mineral structure of apatite, replacing calcium. Now here's the interesting part - uranium in sea water is mostly present as $\ce{U^6+}$ (in the form of the uranyl ion). The uranyl ion is more soluble than $\ce{U^4+}$ so it mostly remains in solution in the sea water. But, as we mentioned earlier, apatite deposits form by the decay of dead marine animals. This accumulation of decaying organic material reduces the $\ce{U^6+}$ to $\ce{U^4+}$, facilitating its incorporation into the apatite structure.

That's only one side of the coin. Apparently $\ce{U^6+}$ can also be adsorbed on apatite grains. This is even used in some cases to stop uranium contamination from migrating through soil - by adding apatite to it in order to immobilise it.

Whatever the exact process (or combination of processes) that make uranium such a good friend of apatite, the end result is that apatite (and rocks containing it) is enriched in uranium relative to its environment.


How do I prepare for the International Earth Science Olympiad?

Here are a few, completely random advices I wished someone would have given me before I started to study geology. I'm aware of that this is over simplified, but I believe that it's good to start easy, gain interest and later, with experience, understand that you have been wrong.

A good book to start with:
Earth: Portrait of a Planet by Stephen Marshak. It is used in many universities for undergraduate students. It has a lot of good illustrations and goes breathy through most aspects of earth science. I'd check that and memorize the diagrams and pictures.

http://www.usgs.gov/ also have plenty of easy accessible material.

Make sure that you understand the concept of tectonics well and use that as a starting point for almost any geological discussion.

Don't forget the most basic physical properties. What works in a laboratory also works in larger scale. (E.g. Density will make light material float and heavy material sink. That's why rivers erodes the paths to the oceans and volcanoes erupt volatile rich lava. Oceanic crust is heavy and continental crust is light.)

Take one hour of your life to learn the geological periods (everyone should!). Use the periods as imaginary folders for fossils, orogenies, mass extensions and whatever you later come across. (E.g. 'Permian' will be something distinctive, just like 'Elephant', 'Qawwali' or 'Andhra'. You'll recognize it when you see/hear/feel it, even if it's difficult to describe in words!).

When you read articles, always start with the latest, and work your way back. In this way you'll start with the modern concept and not get biased by earlier models.

Keep an interest in the present. You should know some biology to understand paleontology, some oceanography to understand deposition and hydrology to understand erosion etc. When you add time, we call it geology.

And, if you start to study and research in geology or anything else, learn LaTeX and learn some basic programming, before you need it.

Good luck with the Olympiad!


Would a global cooling event disable solar energy usage?

I am not sure about the size of Krakatoa eruption but the eruption of Mt. Pinatubo in Indonesia around 12th June 1991 is considered as the largest eruption in the past 100 years. Global average of decrease in solar radiation after 4 months of eruption was about 2.7 +/- 1 W/m^2. Global average surface reaching solar radiation is about 198 W/m^2. In other words, Mt. Pinatubo eruption caused about 1.3% decrease.

The number 2.7 W/m^2 is a global average, so the decrease might have been more in tropical regions and less at high latitudes. It took about three years for stratospheric aerosol amount to return to the background level.

Reference:

Minnis et al., 1993, "Radiative climate forcing by the Mt. Pinatubo eruption", Science, vol. 259, 1411-1415, doi: 10.1126/science.259.5100.1411
Kremser et al., 2016, "Stratospheric aerosol - observations, processes and impact on climate, Review of Geophysics, vol. 54, 278-335, doi:10.1002/2015rg000511


How to tell the difference between real rain and fake rain (cloud seeding)?

What differences exist between natural rain and human “rain”?

The only physically measurable difference between rain from seeded clouds and unseeded is in the seeds/ cloud condensation nuclei/ aerosols that are the surface that moisture can condensate onto and form cloud droplets.
Measurements
You could collect rainwater, evaporate it and the remaining solids were the substances acting as cloud condensation nuclei. This process would get some aerosols from the ambient air, but simultaneously using a device for collecting aerosols and reducing their composition from the rainwater one would lessen this problem. After analyzing the solids one could do some guesswork whether the aerosols were natural or influenced by humans. For example if there is actually deliberate cloud seeding happening you could find traces of silver iodide. Most likely this is not the case and simply heavy pollution has a significant impact on formation of aerosols that can act as cloud condensation nuclei. In this case there are probably some compounds that can be formed only in combustion processes and finding them would mean that they played a role on the formation of the clouds. Doing this experiment in otherwise similar locations with the other having much more pollution would probably be the sanest option. Even after all this you still wouldn't be able to accurately tell whether it would've rained more or less without the pollution. If the air is clean to begin with, adding pollution and thus aerosols the cloud formation would be enhanced and probably then rain too. But if the air already has enough cloud condensation nuclei to begin with then adding aerosols might have the opposite effect; moisture would condense into many small droplets rather a few big ones that create rain.
Modelling
Another possibility would be to study this using a weather model with aerosol dynamics included using measurements of the given location to verify the results. And when the model simulates the reality accurately enough you could tamper with the aerosol fields (by adding and reducing aerosols) and see how the rain is affected. I'm not aware how accurate these kind of models are currently, but aerosol dynamics can make the model easily very heavy.


Mega-tsunami, what is the greatest possible height of a tsunami?

Your question seems to lump at least three different phenomena together: tsunami waves(seismic sea waves), the effects of landslides near the coast, and the effects of asteroid impact into the ocean.  You might have also included rogue waves. Each of these are complex phenomena when you start considering 'realistic' boundary and initial conditions - so you should not expect a highly accurate answer from a simple model.

Seismic sea waves, or waves initiated by land slide, can travel great distances across the ocean. These waves have a long wavelength and therefore may be modeled as shallow water waves. Although the height of classical shallow water wave may be limited (in theory) by the wave steepness (1:7) where the wave 'breaks' and collapses, Computer models of tsunami are likely to be much more accurate.

If you are primarily interested in what happens near a coastline or in a bay, then the most accurate solution will likely be a computer model that also include realistic boundary conditions. See these computer models of a dam break and waves in an irregular water body.

The possible initial conditions for an asteroid impact could be so large that planetary material is ejected into orbit. The Martian meteorites found on Earth are believed to have originated from a impact on Mars. In a large impact, the height of the rim wall might not be an accurate estimate of the maximum altitude material was actually thrown.


How did plants adapt to $\small\sf{CO_2}$ levels past 400k years? Why won't they do it again?

I'm not sure where and why has all CO2 gone every 100.000 years and out of where has CO2 come?

The amount of CO2 in the atmosphere for the last 400000 years is very strongly correlated with temperature.

Temperature change (blue) and carbon dioxide change (red) observed in ice core records.
Image source: https://www.ncdc.noaa.gov/paleo/globalwarming/temperature-change.html.

Glaciations currently occur at roughly one hundred thousand year intervals, driven primarily by Milankovitch cycles. So what causes the strong correlation between temperature and carbon dioxide levels? The primary reason for this marked correlation is that carbon dioxide dissolves in cold water much more readily than it does in warm water.

As a glacial period starts, the oceans gradually get colder worldwide as ice gradually spreads over the Northern Hemisphere. This enables oceans to absorb carbon dioxide from the atmosphere. Atmospheric CO2 drop as a glaciation proceeds. The plot shows that both temperature and CO2 levels drop rather slowly over the course of a glaciation, and then both rise rather quickly as the glaciation ends.

One reason for this is atmospheric carbon dioxide levels. The Milankovitch cycles triggers the end of a glaciation. The warming oceans cannot hold as much carbon dioxide as they could during the depths of the glaciation and release carbon dioxide to the atmosphere. This exacerbates the warming, releasing even more carbon dioxide into the atmosphere. This makes the escape from a glaciation much steeper than the entry into one (Shakun 2012). A nice graph from the cited paper:

Upper plot: CO₂ concentration (yellow circles), global temperature (blue), and Antarctic temperature (red).
Lower plot: Simulation results that show that Southern Hemisphere temperatures tends to lead but global temperatures tend to lag CO₂ levels.
Image source: http://www.nature.com/nature/journal/v484/n7392/fig_tab/nature10915_F2.html.

  But if CO2 came from burning trees or volcanoes and disappeared because plants adapted then I have this question:

  Plants somehow tolerated these 100.000 year CO2 changes over time which is very evolutionary small time. So perhaps adaptation was just about changing plants' composition percentages which is very flexible. When some rare CO2 eating trees came to be more frequent. But if that's true why can't plants change their composition again to adjust for human CO2-emissions pace?

Your question is a bit moot since the increases in CO2 did not come from burning trees or volcanoes and did not disappear because plants adapted.

Jeremy Shakun, et al., "Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation," Nature 484.7392 (2012): 49-54.


Is 2,000 years from now a credible figure for return to glaciation?

It's a little dated and brief, but it's a cool article and I believe it's overall sound in it's predictions and arguments presented.

On the overall point, the author isn't predicting an ice age in 2,000 years, so the answer to your title question is that he didn't really say that, though he writes the article somewhat poorly because that's not very clear, especially when he writes the words "double whammy".   But he's predicting a natural correction to the added CO2 within about 2,000 years, after which the glaciation cycle, but not necessarily an ice age, should return.

The next ice age is hard to predict because Earth's Milankovich cycles aren't adding up right for another 150,000 years, so if an ice age can be triggered by a small push, one could happen in 10,000 years, but a big push isn't due for some time.   More details on the timing of the next glaciation here.

Your author's primary point is that man made climate change won't prevent the next ice age because the Earth will reabsorb the CO2 before then.   He may be right, and I think that's a very sound and fair point to make.  He's not actually saying an ice age will begin in about 2,000 years, though he does seem to imply the possibility.

I think, 2,000 years is likely too soon.   The triggering of ice ages requires cold northern hemisphere summers (He says that in his article too).  Basically, the red line on this chart should be low, and we're in a leveling off and small warming period for the next 50,000 years.  The cycles are adding up in such a way that predicting the next ice age is hard.

On his predictions:

Predicting that mankind will run out of fossil fuels in 300 years is reasonable.   It's something that can't be predicted with accuracy and I personally think it's wrong.   I think we'll move away from coal as climate change gets worse and with abundant deep shale that can be fracked (natural gas is good for cooking and planes need fossil fuels), so I think fossil fuels will remain in use and to some extent, untapped considerably past 300 years, but my opinion aside, his prediction is still reasonable and possible.

Predicting that it will take the Earth about 2,000 years to reabsorb the added CO2 is also reasonable.  I don't think anyone knows how long, or if a new equilibrium will be reached as opposed to a return to how it was, and making this kind of prediction is replete with uncertainties, but 2,000 years is fair.   We should keep in mind that a science based hypothesis can be reasonable and still end up being wrong.   In science as "good" hyopthesis is one that can be tested.   A "good" hypothesis can still be wrong and for estimates this far out, there's room for both his estimate being reasonable and his estimate being very far off the mark.    People sometimes yell at scientific predictions for being wrong, but predicting the future is hard, and people should stop yelling about that because it's not helpful.   Scientists know that not all hypothesis based predictions are accurate, what matters is that a prediction is science based, has correlated cause and effect and can be studied and tested.   (I hope you forgive my little rant, but I wanted to say what a good hypothesis actually means).

Some studies on oceanic absorption of CO2 and other estimates of how long it would take for the Earth to recover might improve this answer, or be the subject for another question, but I'm not feeling the urge right now.   That's a tricky thing to estimate and 2,000 years seems fair enough to me.

It's funny that, today, it's in our best interest to try to stop using fossil fuels, but if/when the next ice age is coming, people might be encouraged to use clean fossil fuels to release more CO2 and prevent the coming ice age.   "go for a drive, it's good for the environment" . . . anyone who's still around in 100,000 years, feel free to put that on your bumper-sticker.   The author also indirectly makes the point that we might want to save some of our fossil fuels as a means of ice-age prevention.   It's a sound point.

I think the article should have been longer and more fleshed out, but it's a good basic article.

I also want to add that while the article is short, he has a 267 page e-book which I imagine, goes into more detail.   https://books.google.com/books/about/Energy_Demand_and_Climate_Change.html?id=EdAgjDtBsNsC


What time and date is the sun directly overhead a given place on Earth?

Having the sun directly overhead can happen only between the Cancer and Capricorn tropics. That is, only the places between 23.5° of latitude north and 23.5° of latitude south.

On the Cancer tropic (23.5° latitude north) it will happen once every year, on the day of the northern hemisphere solstice (about June 21st).
On the Capricorn tropic (23.5° latitude south) it will happen once every year, on the day of the southern hemisphere solstice (about December 21st).
On the equator it happen twice every year. One on each equinox (about March 21st and September 21st).
For any other given place between the tropics, it will also happen twice every year. On the days when the Declination of the sun (a coordinate in the sky analogous to latitude on the Earth), matches the latitude of the place.  Various formulas to calculate the declination to various precision can be found at Wikipedia.

This figure would help to visualize the situation:

The configuration depicted, will happen on the southern hemisphere summer solstice (about December 21st): The only day of the year when the sun passes exactly overhead on the Tropic of Capricorn.

When it comes to what time of the day it will happen, it won't happen at local noon (see this question), the exact time requires a lengthy calculation (see this), but a good estimate would be:

GMT - TimeZone + Longitude/15

Where GMT is Greenwich Meridian Time (the same than Universal Time for this effects), TimeZone is the time zone you are at. For instance -7 for the Pacific Time Zone in North America. And Longitude, is the longitude of the observer (expressed as a positive value for East longitudes and a negative value for West ones). The error of this estimate can be in the order of 15-20 minutes.


Chlorine is a very reactive element. Contrary to your statement, chlorine occurs in many rocks and minerals.

The mineral apatite, with the composition: Ca5(PO4)3(F,Cl,OH), is a natural source of chlorine. Virtually all rocks contain chlorine.

Chlorine even occurs occurs in alkaline magmas.

One of the most common minerals containing chlorine is common salt, which is sodium chloride, NaCl.

Geologically, chlorine is everywhere. When rocks are exposed to water and acids minerals, including chlorine, dissolve into solution and they are transported to lakes, salt lakes, aquifers and oceans.


It would depend on the reflectivity of the material used - a lighter color will reflect more solar radiation and help cool an area fairly quickly , but it would take longer for the area covered with such structures to experience changes in  poleward. energy transport. The poleward heat transport determines where the jet streams are located and how far north and south tropical rains (intertropical convergence zone) move. Thus, whilst the structures would cool the area, there would likely be insufficient rainfall to re-establish substantial plant life and reverse desertification.

In short, because of the need for water and the mesoscale weather patterns in a desert, shading the deserts would have little effect on the rate of desertification.


Extent of desert area influence in local climate

The mediterranian do in a way create its own climate and is partly protected from the north saharan desert by the dominating wind direction in the area.

The dominating wind direction is from west and northwest,The wind blows into the saharan desert in the direction of the equator in the winter,This creates the mild winters the mediterranian is known for.

In the summer more warm and dry air moves from the north saharan desert and into the mediterranian area,this creates the dry summer climate the mediterranan is known for.

So the north saharan desert have the strongest influence on the mediterranian climate in the summer.

you can read about it here https://en.wikipedia.org/wiki/Hadley_cell if you click on the animation you can see how the precipitation changes over the year and thereby also the temparature.

and here https://en.wikipedia.org/wiki/Mediterranean_climate


What was the storm surge height from Hurricane Harvey?

For a general view of the surge in the region, the maps in u-surge give a pretty good idea of numbers and more affected regions.

The USGS provides a comprehensive view of High Water Marks (HWM) in the entire region. If you are looking for observations, then the HWM database gives you the best spatial coverage. While HWM do not provide surge information per se as it includes multiple processes (like ocean surge from the storm, waves and wave run-up, and flooding from rivers and precipitation), it gives an idea of the extreme values of water level in many locations. It also shows the large spatial variability of the effects of the storm. There are also tide gauge and rapid response stations in the area as part of the USGS database that provides more information of the temporal evolution of water levels.

Part of the problem is that storm surge is only the result of two processes: 1) wind piling water against the coast and 2) low atmospheric pressure that causes ocean level to go up. Additionally, you have many other processes affecting water levels during a storm or hurricane. The tides are still there as always and that adds complications because if the storm surge peak occurs during high tide, then the impacts are much worse. Tides in the Gulf of Mexico are not that high, but they can be a much larger factors in some other areas. The combination of storm surge and astronomical tides is often label "storm tide", which is a very poor name choice and leads to much confusion, as clearly the storm does not cause a tide. Another impact is that associated with the high winds, you have large wave heights. As these high waves approach the coast, they cause higher water levels as a result of wave run-up and wave setup. The magnitude of these wave effects can be pretty large in some locations especially in ocean-facing locations. The last main impact on water level is precipitation and the resulting increase river discharge. Clearly, Harvey had a catastrophic amount of precipitation and its impacts were much larger than the purely oceanic-driven storm surge in this storm.

Many agencies are working on developing a measure of water level that includes all these processes. For instance a good example is the USGS effort to develop Total Water Level measurements and forecast.


Why does air pollution comes with cold weather in tropical areas?

Crop burning is a major cause.  Crops are burnt Lal across Thailand between December and march and air movements bring large concentrations south to Bangkok.  Even today islands as remote as Koh Phangan are 135 on AQI.  Can't imagine tourism can work with crop burning.


Do ringwoodite minerals point to an "ocean's worth" of water, or a true subterranean ocean?

A "true subterranean ocean" would suggest a vast amount of liquid water in the mantle. This is most probably not present, for which there are a number of clues.
First of all, when looking at the temperature (~2000K) and pressure (~20GPa) in the transition zone and look at a phase diagram for water it is clear water can't exist as a liquid even though the temperature isn't visible in the diagram. The exact phase isn't clear, it could be a solid or a supercritical liquid.

A second clue is in seismology. Earthquakes produce two types of waves, P-type and S-type, of which only the first can propagate through liquids, see for example this page. As a large body of liquid would produce a large shadow in seismic reflections, and these aren't well known (apart from the outer-core-shadow), it is unlikely there is much liquid water in the mantle.
Also, note that the water in ringwoodite isn't present as water molecules, but as hydrogen and oxygen ions, according to wikipedia.
Therefore, if there is indeed an ocean's worth of water present in the mantle transition zone, it will be there as a solid, which in my opinion can't be called a subterranean ocean.
Phase diagram for water from: http://www1.lsbu.ac.uk/water/phase.html


How can parameters of the ionosphere be calculated?

Answer to that one: What you describe is a measurment, not a calculation.
The measurment you describe varies the potential difference at a satellites Langmuir probe. The potential difference then attracts or deflects ions, and deflects or attracts electrons. Those electrons and ions are the current being picked up by the Langmuir probe.
Then follows a translation of current into local ion or electron densities. Different ion species can be distinguished w.r.t each other because they have different inertia, and thus different arrival times. I'm not sure how many ion species one can distinguish however in this way.


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

First, a short introduction to incompatible elements

The Earth's mantle is mostly composed of the minerals olivine, pyroxene, anorthite, spinel and garnet. These minerals are made from the elements Si, Al, Fe, Mg and Ca. In the figure below I've put them in the MRFE field (Mantle Rock Forming Elements). The trace elements, the elements that occur in very low concentrations, do not form their own minerals and instead are incorporated into the crystal lattice of the common minerals. This is easy in the case elements that share the radius and charge with the major elements because they can easily fit into the crystal lattice (for example Ni in olivine, Cr in clinopyroxene).

Most elements, however, plot out of the MRFE field in the figure and are considered incompatible elements. That is, in the case of mantle melting, these incompatible elements are partitioned to the magma and eventually migrate with it when it goes to form new rocks (for example basalts). Because different processes and conditions of mantle melting result in different patterns and contents of incompatible elements in the new rocks, we can learn about the mantle melting process by studying these elements in more accessible rocks (such as basalts in volcanoes).

Note that I am referring to incompatible elements as incompatible with respect to mantle minerals. In some crustal rocks K, Na and Ti become major elements. In that case the MRFE should be renamed CRFE (Crustal Rock Forming Elements) and expanded to include these elements as well.

HFSE and LILE

The incompatible elements are then subdivided into two groups: the high field strength elements (HFS or HFSE) and the large ion lithophile elements (LIL or LILE).

The LIL name partly gives away why they are called like that: the LIL are indeed larger than other cations. They are lithophile in the sense that they are incompatible and usually end up enriched in the crust (also lithosphere).

The HFS are also enriched in the crust (eventually) but their name derives from their small radius compared to their high cationic charge: the z/r ratio. As a result, their bonding to nearby anions is very strong, that is - they have a high electrical field strength.

The subdivision between the two groups has been defined at z/r = 2.0, but as this is a continuous value, no strict theoretical definition of where the boundary lies can be given. Historically, the REE have been considered as LIL. In more modern times, the REE may be excluded when discussing HFS.

Why do we need the two groups?

Even though both the LILE and HFSE behave in an incompatible way during mantle melting, their response to post-magmatic processes differ. The HFSE are usually immobile: that is, they are mostly resistant to metamorphism and hydrothermal alteration. On the other hand, the LILE are fluid-mobile and hydrothermal alteration may change their contents in the studied rock.

Fresh rocks are a scarce luxury and many rocks that we study have experienced some kind of alteration. Because HFSE are resistant to these processes, their contents are likely to be representative of the original rock. This is extremely important: it is possible to look at a rock beyond the altered mineral composition and the modified major element contents. The LIL can teach us the opposite - we can learn about the alteration processes. If we do find fresh rocks and we find anomalies in the LIL systematics, we can learn about hydrothermal processes that occurred in the mantle that would otherwise not be able to see.

What about hexavalent cations?

One would think that hexavalent cations such as Mo6+, Cr6+, V6+ and U6+ should also appear in the figure as cations with an even more HFS character. However, when in the hexavalent state they form anionic complexes and do not behave like the cations in the figure.

Further reading

MIT OpenCourseWare - Trace-Element Geochemistry

The Use of Trace Elements in Igneous Petrology

About the figure

Inspired by figure 2.2 from Ore Deposit Geology / Scott. Data for figure from An Earth Scientist's Periodic Table of the Elements and Their Ions (also doi)


Regarding the theory of the origin of water on Earth through meteorites, why wouldn't the water evaporate on impact?

why wouldn't that water evaporate on impact, and wouldn't the atmosphere at that time allow the vapours to escape Earth?

The water would very likely evaporate on impact.

However, gravity would prevent the gas phase water molecules from leaving Earth.

The speed of a water molecule must be compared to the escape velocity of Earth (11 km/s) to determine whether or not the molecule can escape.

At a given temperature, the velocity of water molecules will be governed by a Boltzmann distribution.

The most probable velocity of a molecule will be:

$$V= \sqrt{\frac{2kT}{m}}$$

where $m$ is the mass of the molecule and $k$ is Boltzmann's constant.

For example, at a temperature of 300 K, a water molecule will have a most probable velocity of 520 m/s, about a factor of 20 below the escape velocity.

  what is the current scientific opinion of the validity of this theory?

Comets have a higher fraction of deuterium in their water compared to Earth.

According to "Earth's water probably didn't come from comets, Caltech researchers say", this refutes the hypothesis that a large fraction of Earth's water came from comets.


Why is the eastern Pacific full of stratocumulus clouds, and why do they have so much variation in net radiation?

On the east side of the Pacific Ocean, there are cold currents coming the poles going towards the equator. The cold currents makes it so there is almost a permanent cold air mass above the eastern portion of the ocean. As warmer air is blown over this colder air, it must go above the colder air. The warmer air expands, temperature decreases, becomes saturated and the stratus clouds form!

The cold currents are there because of the semi-permanent high pressure system in the mid-latitudes of the ocean. The winds are equator-ward on the east side of high pressure systems. This drives the ocean currents to be equator-ward on the east side of the ocean.


Percentage of dry land surface with sea level elevation lower than 1 km

(Fig. 2.4 of Deep-Sea Biology: A Natural History of Organisms at the Deep-Sea Floor)

8.3% of the Earth's surface is above 1 kilometer.

This corresponds to about 29% of the land area.

So 71% of the land area is below 1 km.


Is there a conventional list of pollutants to consider for calculations? Or an updating one even?

In the USA there are two classifications of airborne pollutants. They are

Criteria Air Pollutants

There are 6 separate air pollutants. These make the bulk of the regulation, especially for the Clean Air Act. Each pollutant has different standards to adhere to. Examples include lead, ozone, and particulate matter.

Hazardous Air pollutants

This is a list of 187 pollutants. These are cancer-causing pollutants, but are usually in pretty low concentrations. Examples include asbestos, lead, and benzene.


In your calculation, did you use albedo correctly? Remember, albedo is the ratio of reflected radiation to total radiation, and 1-albedo is the ratio of absorbed radiation to total radiation.
Edit: Make sure you are plugging the numbers in correctly too.


How do they determine the "feels like" temperatures for weather data?

The "feels like" value is calculated based on temperature, but altered depending on wind (cold temperatures) or humidity (hot temperatures).  Think of it this way:

1) if it's freezing cold outside, the wind will make if seem even colder because any body heat you have will be blown away quickly.
2) if it's hot outside, high humidity will make it seem even hotter because your sweat won't easily evaporate.

From wunderground:

  The Feels Like Temperatures map show what the outdoor temperature will feel like for the current day. Feels Like Index is a factored mixture of the Wind Chill Factor and the Heat Index. The combination of the heat index and the wind chill factor are denoted collectively by the single terms apparent temperature or relative outdoor temperature or simply Feels Like.

  Wind Chill

  Wind chill is the apparent temperature felt on exposed skin, which is a function of the air temperature and wind speed. The wind chill temperature (often popularly called the wind chill factor) is always lower than the air temperature, except at higher temperatures where wind chill is considered less important. In cases where the apparent temperature is higher than the air temperature, the heat index is used instead.

  Heat Index

  The heat index (HI) is an index that combines air temperature and dew point in an attempt to determine the human-perceived equivalent temperature — how hot it feels, termed the felt air temperature. The human body normally cools itself by perspiration, or sweating, which evaporates and carries heat away from the body. However, when the relative humidity is high the evaporation rate is reduced, so heat is removed from the body at a lower rate causing it to retain more heat than it would in dry air. Measurements have been taken based on subjective descriptions of how hot subjects feel for a given temperature and humidity, allowing an index to be made which corresponds a temperature and humidity combination to a higher temperature in dry air.

  The heat index is derived from work carried out by R. G. Steadman. Like the wind chill index, the heat index contains assumptions about the human body mass and height, clothing, and the wind speed. Significant deviations from these will result in heat index values which do not accurately reflect the perceived temperature.


It is mammatus. The individual cells are hanging down, but it just isn't very obvious from your perspective. Nice photo. Usually one doesn't have much time to photograph mammatus because of its inherently unstable condition.


How does soil redox potential affect the rate of denitrification?

Denitrification requires anoxic conditions, organic matter, and NO3-.

Gleysols are anoxic soils formed in wetlands. Waterlogged wetland soils are generally both anaerobic and high in organic matter. For a given concentration of NO3-, denitrification rates should be higher in Gleysols than similar soils that are aerobic soils (because there will be less organic substrate and less anaerobic habitat).

Notably, even in aerobic soils, denitrification can occur within anaerobic microsites.

references:

Bedard-Haughn 2010. Prairie Wetland Soils in Prairie Soils and Crops Journal (pdf)
Schlesinger and Bernhardt 2013 Biogeochemistry 3rd Edition p 205-208


Why is Earth's age given by dating meteorites rather than its own rocks?

Some background:

We are able to determine the age of certain rocks and minerals using measurements of radioactive and radiogenic isotopes of certain elements. The most common are U-Th-Pb, Rb-Sr and Sm-Nd. Simply put, the resulting date is the time that has passed from the crystallisation of that mineral. Obviously there are complexities, but there are not critical for this answer.

  Why do we use meteorites if they hit the Earth after its formation?

Short answer: because the meteorites formed together with the Earth and the rest of the Solar System.

Long answer: The Earth formed together with the rest of the Solar System and its meteorites around 4.5 billion years ago. When meteorites fall on Earth and you pick them up, you are able to date the time of their formation.

You say:

  Why do we use meteorites if they hit the Earth after its formation?

You have to distinguish the time that the meteorites form and the time that they hit the Earth. If I throw a meteorite at you, and you date it, it still records the formation time and not the time that I threw it at you. Hitting the Earth does not reset the radioactive clock in the meteorite's minerals.

  Wouldn't it be more accurate by doing it with its inner materials?

It would. There are two problems:

We don't have materials from the time of Earth's formation. The Earth is a dynamic place, and rocks are getting formed and destroyed all the time (also see related question). It may be that such old rocks exist on Earth, but because they are so old there are either metamorphosed and buried deep in the Earth or covered by sedimentary rocks. The oldest exposed rock on Earth available for study is the 4 billion year Acasta Gneiss in Canada. The oldest mineral on Earth is a zircon found in Australia, which is 4.4 billion years old. These are the only two materials that are known to be older than 4 billion years on Earth. There could be more, but we just couldn't find them.
The moon forming event occurred some tens of million of years after the formation of the Earth. This event destroyed the Earth's crust and any evidence of the age of the Earth, on Earth itself.

This is why meteorites are excellent for this task - they mostly formed during the formation of the Solar System.


In geological terms, "dissection" appears to refer to the creation of cuts in a landscape due to erosion e.g. by the flowing of streams. Dissection rate would then be the rate at which such cuts in the landscape form.

https://books.google.com/books?id=AIyIAAAAMAAJ&pg=PA221&lpg=PA221&dq=dissection+rate+geology&source=bl&ots=bFXfYFDmt3&sig=CiiKojDNHIkyQxzqVkBuSyL1Zr0&hl=en&sa=X&ved=0ahUKEwiVgpOLm8TZAhUKnOAKHXQQBMMQ6AEIUjAI#v=onepage&q=dissection%20rate%20geology&f=false


Large Igneous Provinces are like Lunar Mare?

I disagree with Michael about the "not as large as the lunar mare" part. Head and Wilson (1992) mention that the "total area of exposed mare deposits is about 6.3 millions km2" (17 % of the Moon's surface area). They estimated a total volume of 10 millions km3. The largest mare, Oceanus Procellarum, covers about 4 millions km2.

These values are quite comparable with Large Igneous Provinces (LIPs) in terms of area, and are even one order of magnitude lower in terms of volume. From the Encyclopedia of Volcanoes:

  The composite Ontong-Java-Manihiki-Hikurangi plateau covers 3.5
  million km2 with an estimated volume 59-77 million
  km3. [...] The Kerguelen plateau in the southern Indian
  Ocean is the second largest LIP, covering 2.3 million km2
  with a volume of 15 million km3 [...] Not all LIPs are
  oceanic plateaus; for example, the North Atlantic volcanic province,
  derived from a hot spot presently centered beneath Iceland, has an
  area of 1.3 million km2 [...] Also notable are the Deccan
  traps in India (1.8 million km2/9.3 million
  km3).

If lunar maria seem that large from Earth, it's only because the Moon is small!

But to know if lunar maria or LIPs would have looked like "glowing lava oceans shinning in the night", we need to look at emplacement rates rather than just areas and volumes. From the same chapter, one can calculate LIP emplacement rates of ~3-13 km3 per year. It may seem quite low (for comparison, ocean ridges quietly produce ~20 km3 per year), but it is an average output rate over a few million years. As noted on largeigneousprovinces.org, their might be pulses of magmatic activity, with peaks in production rate. This is exactly what's been inferred for lunar maria by Wilson and Head (2017): even if the average output rate has been calculated at a very low 0.01 km3 per year, they found that some flows could have been emplaced with rates up to 106 m3s-1!

As to whether this would have been visible from space: define "from space"! From low Earth orbit like the ISS? From the Moon itself? :)


What is a pre-monsoon shower? Is there any distinguishing feature between monsoon and pre-monsoon showers?

Mango showers, or ‘mango rains’, is a colloquial term to describe the occurrence of pre-monsoon rainfall! Monsoon is prevailing wind due to seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea. Usually, the term monsoon is used to refer to the rainy phase of a seasonally changing pattern. They are notable across much of South and Southeast Asia, including India, and Cambodia.

https://en.wikipedia.org/wiki/Monsoon here is a helpful resource I used!

:)


Approximation of ancient landmasses using current ocean floor data

over that short a time there would be very little change in the land itself, all you really get is a sea level change due to changes in the ice sheets, continental movement is barely noticeable.
such measurements and maps already exist.
here is the earth 12,000 years ago.

Here is the same map with the changes highlighted.

sources for other maps
https://www.fieldmuseum.org/pleistocene-sea-level-maps
http://antiquity.ac.uk/projgall/sakellariou334/
Or you can even use this interactive map, which already does what you want to do, and compare it to past sea level.
As for why projecting backwards is easy, you may want to look up the term "continental shelf".


How do I derive the formula for lithostatic (overburden) pressure?

This isn't that difficult, but anything is if you start from the wrong place. Let's derive this thing:

$$P = \frac{F}{A}$$

Where $P$ is pressure, and $A$ is the area the force is pushing down on. Let's take a break and derive the units first, just so we know our end derivation is correct; $F$ is in Newtons, which comes out to $\mathrm{kg} \times \frac{\mathrm{m}}{\mathrm{s}^2}$ and $A$ is in $\mathrm{m}^2$. This means that pressure is $\frac{\mathrm{kg}}{\mathrm{m}\times\mathrm{s}^2}$. So your first substitution is correct.

Now that that is established, let's think about lithostatic pressure, and break up the original equation:

$$P = \frac{M \times a}{A} $$

We know that $a = g$, gravitational acceleration, but what we really want is to figure out how to get this equation in terms of density, so

$$\rho = \frac{M}{V}$$

where $\rho$ is density, $M$ is mass, and $V$ is volume. If we substitute this equation in for mass in the pressure equation, we get

$$P = \frac{\rho V \times g}{A}$$

let's now separate $V$ and $A$, $$V = \ell \times w \times h$$ $$A = \ell \times w$$

So canceling out $\ell$ and $w$, our final equation shows

$$P = \rho gh$$

or lithostatic pressure.


which are the two countries with the flight time between them and time zone differences are equal

I'm not going to look for examples, but there will be some. More interesting is to consider the underlying geometry:

At one extreme, if you fly from north to south (or vice versa) you'll experience little or no change in time zone no matter how long you fly for.

At the other extreme, if you fly from east to west the time zones will go in the wrong direction. Depending on how you define the question there might be an "answer" in this direction, where you fly west for n hours and go back by n time zones. But for the rest of this question, let's assume you want later time zones.

If you fly from west to east, you're chasing the time zones in the right direction... but unless you have a supersonic aircraft, you can't go fast enough - you will travel east slower than the rate at which the earth is spinning, so (as long as you go far enough for more than a 1 time zone change, i.e. to get out of rounding errors) the number of hours you fly for will always be more than the number of time zones you gain.

So to match the two, you must fly diagonally : north-east or south-east. The exact angle will depend on the speed of your plane and the latitude that you start from. And then, you have to find a city along that line!


Your image looks very similar to rocks we get here on the West Coast of Vancouver Island.  We have some rock boring bivalves that will effectively drill into the rock which breaks off and erodes into a shape similar to what you are showing.  https://en.wikipedia.org/wiki/Pholadidae or https://the-hazel-tree.com/2013/08/21/piddocks-anything-but-boring/

There are also echinoderms that will bore into rocks, Strongylocentrotus purpuratus, https://en.wikipedia.org/wiki/Strongylocentrotus_purpuratus
https://bmscblog.wordpress.com/2013/01/09/holey-rocks/  but the holes from these creatures tend to be larger than the image you present.

I a confident that the holes are created by some form a boring bivalve.


Does the long-term ice-core temperature record provide reasonable evidence that the current temperature trend is not anthropogenic?

No, ice cores do not refute human-caused warming.  In fact, they support it.  Your logic really doesn't follow because the rate of warming now compared to some arbitrary previous date is not  related to whether the warming is driven by humans.  Instead, it is important to consider the natural variation of physical factors that affect climate (collectively known as Malenkovitch cycles; http://en.wikipedia.org/wiki/Milankovitch_cycles ), and then recognize any large deviations from those cycles.

An image of the EPICA and Vostok ice cores versus age obtained from http://en.wikipedia.org/wiki/Ice_age , clearly shows influence of the Malenkovitch cycles.  The most notable of which is the strong cycle that is approximately 70,000 years and is associated with geologic ice ages. In fact, the Earth is historically on average much cooler than it is now, and the retreat of glaciers has been periodic but not sustained.  We were supposed to have cooled off some time ago, but clearly we are not in a global cooling period. Many would even argue that humans started affecting the climate over 7,000 years ago when land management and fire was wielded prevalently.

In order to attribute climate change to humans, climate models are run with and without anthropogenic climate forcing.  When they do so, climate models run without anthropogenic forcing are unable to duplicate the current warming trend.  I've attached an image of this from the IPCC AR5 Technical Summary draft which shows a full climate simulation, one without anthropogenic climate forcers, and one with no aerosol forcing for comparison.

Finally, I thought someone might value this link that discusses climate change atrribution:
http://www.realclimate.org/index.php/archives/2014/08/ipcc-attribution-statements-redux-a-response-to-judith-curry/comment-page-4/


How big of an event is needed to trigger a long winter?

A small meteor/asteroid impact might trigger a nuclear winter, but it would be registered by people and it would be very unlikely to trigger an ice age unless the impact created a very large amount of dust in the atmosphere. The dust would need to stay in the atmosphere for a decade or more to trigger an ice age.

A natural nuclear explosion cannot be very large because as soon as critical mass is reached it will explode so the size of the explosion is in a way self limiting. If this happened under the world's major ice sheets it will melt a relatively large amount of ice but this would be registered by an increase in radioactivity in sea water (possibly many years after the explosion took place). So this would not trigger an ice age.

A large volcanic eruption can cool the earth for a few years but is unlikely to trigger an ice age unless it lasts for several decades, and yest again, this would be registered by people. You can take a look here to see what kind of magnitudes that have happened in our history https://www.ranker.com/list/the-worst-volcanic-eruptions-in-history/drake-bird

When you ask about an overlaying thermal cycle (as in heating until the temperature crashes), this is very unlikely to happen unless the temperature reaches a point where a very large part of life gets eradicated, as the temperature on earth goes up the ocean can hold less and less CO2 until at one point the oceans starts to release more CO2 than it absorbs from the atmosphere. This means the heating will not trigger cooling unless life on our planet is significantly reduced.

Water can hold less dissolved gasses when the temperature goes up, so at one point aerobic life in the ocean can no longer survive due to the lack of dissolved oxygen in the water.

This is just about how serious it might get if we keep on going like we are now.


Why have "ozone-depleting substances" led to a third of all global warming and half of arctic sea ice loss?

The Global warming potential (GWP) describes how much global warming a particular gas may induce in a particular time period.  It is often expressed in terms of CO₂-equivalent.  The best known greenhouse gases are carbon dioxide (CO₂), methane (CH₄), and water vapour (H₂O).  Water vapour is short lived and therefore its emission is not a primary climate change contributor (but it is a strong secondary contributor through the water vapour feedback).  However, there are other greenhouse gases that are, per unit volume, extremely strong.  Some of those are CFCs and HFCs.

Wikipedia quotes various IPCC reports and summarises the 20-year global warming potential of some greenhouse gases (emphasis mine):

CO₂: 1 (by definition)
Methane: 86
Nitrous oxide (N₂O): 268
HFC-134a: 3790
CFC-11: 7020

The GWP is a result of a combination of the strength of radiative forcing and atmospheric lifetime.  The radiative forcing is about 20,000 times stronger, due to those complicated molecules having lots of rotational and vibrational states that can absorb IR radiation.  Fortunately, their lifetime is also shorter, resulting in an estimated GWP of around 7000-11000 for commonly used CFCs.

So to answer your first question: yes, ozone-depleting CFCs have a very strong greenhouse gas potential independent of their ozone-depleting properties.  Their replacement, HCFCs, are much more gentle to ozone but still very strong greenhouse gases.

I'm not sure why their effect is relatively stronger in the Arctic.  The research article you linked provides some ideas:

  It is also legitimate to ask whether such a large contribution of ODS to Arctic warming might be an artefact of the CAM5LE model.
  (...)
  In addition to a larger RF, two factors produce an enhanced Arctic warming with increasing ODS in CAM5LE: (1) a stronger lapse rate feedback (which is positive for the Arctic, confirming previous work) and (2) a weaker negative net cloud feedback (with contributions from both long and short waves).

Note that the article seems to entirely ignore that HFCs are not phased out at all — HFCs have largely replaces CFCs because they don't destroy ozone, but still have a strong GWP.  I find that a rather serious omission because it strongly undermines their conclusion that the phase-out of ODS, which is well under way, will substantially mitigate Arctic warming (the article groups HFCs together with CFCs, which makes sense for GWP but not for ozone depletion).


Why would a Martian tsunami travel at only 200 km/hour, four times slower than on Earth?

The linked paper does numerical modelling of a hypothetical tsunami and predicts speeds between 60 m/s (at its point of origin) and 30 m/s (nearer to shore). We can try a back-of-an-envelope approximation to see if we get close, and to understand why the speed would be so much lower than on Earth.

A tsunami behaves as a gravity wave with a very long wavelength. In shallow water (and pretty much anywhere in Earth's oceans counts as shallow water for such a long wave), the speed at which it moves is approximated by

$$V = \sqrt{gD}$$

where $V$ is the wave's speed, $D$ is the depth, and $g$ is the acceleration due to gravity.

On Earth, $g = 9.81$ m/s2 and, in the deep ocean, we might assume a depth of 4 km and obtain a speed of 198 m/s, or 713 kph.

Let's try this for Mars. As you've identified, the acceleration due to gravity on Mars is about 3.8 m/s2, and the linked paper gives assumed depths of the ocean on Mars as between 100 and 1200 m (forgive me if this is not quite right - I've only skimmed the paper, and these figures come from Table 1). Let's assume a 1000 m depth, since the highest speeds will be found in deep water:

$$ V = \sqrt{ 3.8 \times 1000 } = 61.6\ \textrm{m/s} $$

which is close enough to their value for comfort. So a tsunami on the Mars described here would be much slower than on Earth due to the weaker force of gravity and the shallower depth of the ocean.


How to handle negative cosine of Solar Zenith Angle while calculating clear-sky UV Index?

This is only to address the title question.

You are right, in a way. I would recommend that you set an if statement up such that

if cos(sza)>=0:
   raw_uvi = 12.50*pow(cos(sza),2.42)*pow(float(ozone)/300,-1.23)
else:
   raw_uvi=0.0

This makes it so that when the sun is beneath the horizon, the sun is not 'taking back' the energy


In a zero carbon future but with increasing energy requirements would Earths oceans continue heating?

Short answer: Yes, the ocean would continue heating for a while if we cut off all greenhouse emissions. Simply because CO2 has a long life span in the atmosphere and its effects will continue to be active for a long time, longer than human life spans.

Also, it may be that thresholds have already been passed that lead to positive feedbacks, like glacier retreat or desertification that amplify the forcing effects of greenhouse gases. Deforestation and wild fires are another such positive feedback, they release a lot of CO2 for immediate warming effect and expose a surface ready to be eroded and not available as a carbon sink any more.


In the blog post, "[They] start with a pressure gradient." So I'll discuss how a pressure gradient force develops at the jet streak level and why it develops at the jet streak level.

First let's go over some basics. From the meteorological perspective, one can think of pressure as the amount of air mass above a point (gravity provides the acceleration). So high pressure means relative large amounts of air mass above a point and low pressure means a relatively low amount of air mass above a point.

Now, think of two columns of air that start at surface and go into space. One column is really cold and the other column is really warm. Warm air is less dense than the cold air. If the cold air column and the warm column have the same amount of mass, the warm air column will be taller. If the two columns have the same mass, the surface pressure of the two columns will be the same.

If we travel up these two columns we would expect the pressure to decrease with them as the amount of mass above us decreases. The pressure in the cold column would decrease faster than the mass in the warm column as we travel up the columns. This means at a certain height, say 10 km, the pressure in the warm column will be much greater than in the cold column (see image below). This is a pressure gradient and causes the jet streak in the link you posted.

So how do we get cold air column next to warm columns? Those are fronts! A northern hemisphere warm front typically will have cold air to the north and warm air to the south. So the pressure gradient force at 10 km above the surface (about jet streak level) will be from south to north (note: the pressure gradient is from north to south in this example). Wind wants to go from south to north but is deflected by the Coriolis force as explained in the blog post. Now check out a weather map, you'll find the jet streak will be over a surface warm front!

Now, as we keep going up, the maximum pressure gradient will be at the jet streak level. Above the jet streak level, is the stratosphere which contains ozone. O-zone absorbs radiation and warms the air around it. The stratosphere starts at a lower altitude over cold surface air, so our pressure gradient begins to shrink above the jet streak.

In other words, the jet streak is at the maximum pressure gradient. Which occurs above the boundary of cold air and warm at the surface.

From: http://apollo.lsc.vsc.edu/classes/met130/notes/chapter10/graphics/pf_xsect2.free.gif

This picture does a good job of showing how cold air will have lower pressure than warm air aloft.

Edit: I should mention, fronts and jet streaks are kinda a chicken and egg scenarios. They each cause each other to some degree.


How much energy is released a year of all the lightning on earth?

Some basic math on this:

About 100 bolts of lightning hit the Earth every second and they average about a billion joules of energy be bolt.   That's 3.1 billion lightning strikes per year, coming to about 3.1 billion billion joules per year, or about 860 billion kilowatt-hours (kwh) of electrical energy per year.

That estimate is pretty rough as some estimates have as much as 5 billion joules per bolt of lightning, pushing it up over 4 trillion kwh/year.

Total human electrical usage, per source is about 18.1% of 104 trillion kwh/year, 2012 numbers, 18.9 trillion kwh/year of electricity generated.    So even if all the lightning energy was utilized (which would be unlikley for a few reasons), it would be somewhere in the 4%-20% range of our total electrical demand, which isn't bad, but I think that's the answer to your question.  There's not enough energy in all the lightning on Earth to supply our electrical demand.

Wikipedia has an article on the logistical difficulties.   It's perhaps doable, to some extent, but at best, lightning could provide only a small percentage of our electrical needs, unlike solar panels which could provide, at least in total energy, well in excess of our electrical needs.   Solar runs into problems like it's not always on, which is a limiting factor to it's usefulness, but in terms of total energy provided it's much easier and much more abundant than harnessing lightning.


Are you more likely to get a sunburn at the pole than the equator?

Assuming that your skin is exposed, you are standing upright are out when the sun is out, yes.

You don't even need to be very polar.

I live near Edmonton Alberta -- latitude 54 degrees.

At the equinox, the sun is at 54 degrees from the zenith.  At winter solstice it is 54 + 23 = 77 degrees from the zenith, or 13 degrees off the horizon.

No joke:  We use our car's sun-visors driving south at noon.

So if I'm standing up outside, I'm getting roughly the kind of sun intensity you would get lying flat on the beach in more tropical climes.  Since you aren't really hot, you can get a burn without your usual warning signs.

Confounding factors:

The sunlight is traveling through more atmosphere which reduces intensity somewhat.  At 13 degrees, the light path has about 4 times as much air in the path.  Which increases the amount of sunlight that is absorbed -- but not by a factor of 4.  The difference between sunlight in space and sunlight at the surface is about 30% overall, but adding to the air column will only increase the absorption of frequencies that are partially absorbed by a more vertical column.

Polar latitudes, and less polar ones in winter when solar angles are low, will tend to have less dust, water and smoke in the air, increasing air's transparency.

You get reflection off the snow which can come close to doubling your exposure.  Some of the worst sunburn's I've gotten have been on winter days on my poor nose.  (Sticking out of my face it's getting direct sun, reflected off of snow, and reflected off of face.)

One useful measure of the relative intensity is to look at the exposure information for photographs.  (You have to know the film speed or digital ISO as well as shutter speed and f/stop) I find that exposures in sunlight at 'low noon' in winter are comparable to summer ones.

Day lengths are short.  At winter solstice we theoretically have about 9 hours of daylight.  When the sun peaks at 13 degrees however there are a lot of shadows.

The weather tends to discourage large displays of skin, although I've split wood without a shirt on a calm sunny day at -10 C.  In general when dressing for outdoors I figure that bright sun in winter is equivalent to 10-15C degrees warmer, since it's hitting more of me.


What factors influence cloud height and type?

It depends on the height of the troposphere. On the equator troposphere has at least 12 km height, but in the polar latitudes it might be even less than 8 km. That difference in troposphere altitude allows clouds to form differently depending on the latitude. The second reason is that higher parts of the troposphere closer to the equator are warmer and contain more moisture than in the polar region.


Is the color of the sky the same everywhere on earth?

Absolutely not. While the answers by casey and farrenthorpe correctly state that the blue color is due to Rayleigh scattering, the composition of the atmosphere varies considerably from place to place - and with different composition come different degrees of scattering, and different color / intensity. Typically regions of greater industrial activity will carry larger densities of particles which, in the presence of moisture in the air, will become scatterers. The wavelength dependence is a function of the size of the particles - so as the size changes, so will the color.

See my answer to the question Why is the sun brighter in Australia compared to parts of Asia. The same mechanism that makes the sun "brighter" also makes the sky "darker" (namely, less scatter).

This is true even on a nominally "clear" day - because there is always some particulate matter in the atmosphere. And the concentration of particulates really does vary with location on earth - see this image  as an example (from NASA).

The other point worth keeping in mind is altitude: the sky looks darker when you are at the top of a mountain, even if the composition of the atmosphere is the same. That is because there is "less atmosphere" to scatter. And of course, some places on Earth are (always) at a different altitude...


See here for some ideas.  You may want to do some testing, at least for Mohs hardness.  But comparing your samples to the typical pictures shown in the referenced site I would guess an alkali feldspar (hardness = 6)  or perhaps rose quartz (hardness =7).  Note the hardnesses, a steel file falls in between at 6.5.


Terms:
Intraplate volcanism - as the name suggests it is volcanism within the plates rather than at plate boundaries.

These are also known as hotspots.

Ocean island basalt (OIB) - is the basaltic rocks associated with intraplate volcanism.

Relation between mid-ocean ridges and hotspots:

Hotspot–ridge interaction produces a wide range of phenomena including excess crustal thickness, geochemical anomalies, off-axis
volcanic ridges, and ridge relocations or jumps.

For further study refer to this research paper.

A conceptual schematic of a ridge jump from that paper:

Image Source

DR: Dying rift
PR: Propagating rift

There is a ridge jump towards the hotspot.  Due to the ridge jump lithosphere from plate B is transfered to plate A.


Are there any flights that fly east both from origin to destination and from destination to origin?

FlightAware suggests there are no non-stop flights from LA to Delhi.

Was certainly going to point out that we're pretty limited on ultra long-haul flights still, and it'd take a very special flight setup to make your scenario.  You'd need both:

Two locations about 180° longitude apart so that the distance going east vs. the distance going west is insignificant for both legs enough so the jet stream gains flying east pay off.
Two places at just the right latitudes.  They need to be at latitudes far enough south (in the NH) that it's not much shorter to just fly the great circle through the North Pole [or near if not 180° apart].
Here is a graph showing the ratio of the distances of the path crossing the Pole vs the distance of the constant-latitude path, for places 180° longitude apart [derivation in comments]... which shows it's 50% longer to fly around the 60° latitude circle than to fly over the Pole).
However, the further equatorward (south in the NH) you go, the less benefit you'd get from the jet stream as upper wind speeds are typically much slower further south, and you'd spend less of your flight time in the jet stream.  (Here's a current jet stream map).

Keep in mind that the jet stream is only going to add 100-200 mph in general.  So that's only like 1/3 of the cruising speed of a large jet.  Of course the benefits will show up in both in fuel usage (and the additional weight benefits of carrying less fuel) and in travel time (people like quicker flights, and you can run more flights in a year and/or pay crew less).  So despite being a longer distance, if it cut enough time/energy it might just be worth it.

And, well go figure, it turns out you weren't far off at all!  Because there actually is a direct flight from San Francisco to Delhi.  And it looks like they do exactly as you suggested!

(Click images for larger versions)

These are Air India flights 173 and 174.  The official flight does make a jaunt from Delhi to Bengaluru and back once it completes the SFO-DEL leg.  But you could indeed go around the world from Delhi to San Francisco to Delhi without any other stops... in looks like around 36 hours.

Pretty cool!


Are the precious metals (silver, gold, platinum) present everywhere throughout the Earth's crust at least in the trace quantities?

The average concentration of gold in Earth's crust is about 2 ppb (±0.5, depending who you're asking). This is about 2 milligrams Au per tonne of rock. It's not much, but it still equals about 6×1018 atoms, or 6 billion billion atoms.

Seawater has on average 0.004 ppb of gold. This equals 4 micrograms Au per tonne of seawater. Much less, but still about 1×1016 atoms of gold, or 10 million billion atoms.

So to answer your question:

  ...contain fewer than one atom of gold per cubic meter or tonne of
  their mass

The answer is a clear no.

Edit

These seemingly huge numbers do not mean that there is a lot of gold in the rock. That 0.004 ppb of gold which means 10 million billion atoms, is still only 0.0000000004% of the rock. This is clearly a completely insignificant amount of gold. Nonetheless, this insanely tiny amount of gold still an insanely large amount of atoms of gold. There are a lot of atoms out there.


According to Howarth, et al. 2011, from 4 wells they sampled, flow back after hydraulic fracturing lead to a release of methane equal to 0.6-3.2% of lifetime production of the well. Fracking wells released methane equal to 3.6-7.9% of lifetime production from all sources, while non-fracking wells released 1.7-6.2% of lifetime production.

Petron, et al. 2014 come to similar conclusions, though they don't provide data for lifetime individual well production to allow comparisons. They measured from an aircraft and found 10ppb to 100ppb increases in methane concentration in the air above wells at the Denver-Julenberg fracking site. They note that their estimated methane release is 2-3 times higher than the EPA's estimates (i.e. the estimates under which the fracking company filed its environmental impact statement). I don't like this study as much due to lack of information about what stage of production the wells are at (if they fracked two years ago and are still pumping, then this is just due to leaky pipes, not due to the fracking process).

In any case, there is some significant evidence that fracking is releasing more methane than it is expected to. The first paper adds some discussion of prevention measures and such.

I will say this, it barely matters in the long run if the methane is leaking or being pumped into your furnace and burned. Methane isn't going to last too long in an oxygen atmosphere, and its all going to end up as CO$_2$ sooner or later.


Why is the diurnal temperature range on the Cascade volcanoes so small?

I think the answer to this question can be split into two parts. First, it is important to know which weather model you are using. Weather models use grids to predict the weather. The finer the grid, the better the topography (mountains) are represented by the weather model. To get a reasonable representation of the mountains that you mention, you would need a horizontal grid spacing of a few kilometers at most.

For the second part of the answer, we will assume that the weather model you are looking at has a fine grid. The only effect that I can think of explaining the strong difference in the daily cycle between Seattle and the mountains, is the wind. At higher altitudes, radiative cooling cannot effectively bring down the temperatures since the air is continuously being mixed with air from the free atmosphere which has a much less pronounced daily cycle.


The Wikipedia entry for Zoeppritz equations says:

  A full derivation of these equations can be found in most exploration
  geophysics text books, such as:

  Sheriff, R. E., Geldart, L. P., (1995), 2nd Edition. Exploration
  Seismology. Cambridge University Press.


Why does relative humidity drop if I open the window in winter? What about the temperature drop?

Let's do this with accurate equations. We know how to calculate the saturated water vapour pressure for temperature $T$:
$$e_s(T)=e_{s0}e^{\frac{h_i}{R_w}(\frac{1}{T_{s0}}-\frac{1}{T})}=610\text{ Pa} \times e^{5423(\frac{1}{273\text{ K}}-\frac{1}{T})}$$
$e_s$ is saturated water vapour pressure as function of $T$ in Pascals
$T$ is the temperature in Kelvins
So, the saturated water vapour pressure at $T=0°C=273K$ is equal to $e_s(273K)=610 Pa$. Similarly, $e_s(293K)=2360Pa$ and $e_s(283K)=1230Pa$.
So we have two parcels of air: 1. 20°C, 40% and 2. 0°C, 40%. What are the masses of the water vapour in both parcels?
$$e=f\times e_s(T)$$
$f$ is relative humidity, $e$ is the water vapour pressure
$$m(T)=\frac{eV}{R_w T}=\frac{f\times e_s(T)\times V}{R_w\times T}=\frac{fe_s(T)V}{461\frac{J}{kg}T}$$
$$m(293K)=0.0070kg$$
$$m(273K)=0.0019kg$$
The next step is to combine these two masses:
$$M=m(293K)+m(273K)=0.0089kg$$
So the density is $\rho=\frac{M}{V}=0.0045\frac{kg}{m^3}$
The water vapour pressure is given by:
$$e=\rho RT=587Pa$$
The relative humidity is then:
$$f=\frac{e}{e_s(283K)}=0.477$$
So this is around 48% of the relative humidity.
Why did I put here so many equations? Simple! These equations hold on high degree of accuracy, so they can't be wrong. Why would the relative humidity drop in reality?

Also, for Skew-T Log-P lovers:

This solution is even more concise and less error prone.


I think Wikipedia explains quite well. It is the wind that transport the airborne water droplets from a nearby showering cloud. It is quite common in UK especially near the coast which is often very windy. Usually the weather forecast will say that it has scattered shower with sunny spell.
https://en.wikipedia.org/wiki/Sunshower


What is the current status of geophysical global cooling theory?

The effects one can see on other planets (and many of the icy moons in the solar system) are typically faults and scarps due to the fact that during cooling, these bodies contracted. Since the surface was solid, the only way to accommodate the contraction is through faults.

But Earth's surface is not solid on long time scales. We have plates that move, scrape, and subduct. If you shrink the perimeter of Earth slowly, you don't get compression faults. Rather, you're just going to accelerate subduction a little bit and maybe slow down mid-ocean ridges a bit.

In the end, the point is that the system of plates that covers Earth can accommodate slow shrinkage of Earth without producing visible faults.


How are Earth's rotational changes due to large earthquakes calculated?

Earthquakes, specially those at subduction zones, result in redistribution of mass (as one plate slides on top of the other). This change in distribution of mass causes changes in gravitational field that can be measured by satellites such as GRACE.

Now angular momentum is conserved. If we know the change in mass then we can calculate the change in moment of inertia and thus the change in the angular velocity.


Is this a contradiction in Wikipedia's definition of temperate zone?

Note that they say:

  the temperate or tepid climates of Earth occur in the middle latitudes

The word in can be used to convey that the first thing is only a part of the larger second thing... much as, for example, Texas is found IN the United States, or the preteen years are found in childhood.

But by including the additional further explanation of what the middle latitudes are directly after that, I agree it leans a reader towards your interpretation, and is ambiguous and likely confusing to others.

I'll try to make some minor adjustments to the article to hopefully alleviate any confusion.

But in all honesty, it's probably better to not get overly caught up in such excessively precise categorizing.  I tend to believe that what one person, even one climatologist, might call temperate climates may well vary from what another one would classify them.
For example, they can be based on temperature ranges, on prevailing wind patterns, on breaking into equally-sized regions (like Fred commented), etc.

Really, I'd think of the subtropics as sort of a blurry boundary between the tropics and the temperate zone... where the closer you get towards the Equator, the less seasonal variability and frequency of cold air intrusions.

Indeed, even typical places well across into the "official Tropics" can see occasional years with some notable cold fronts, as happened in Cuba and even Costa Rica in the winter of 2010.  So it's not like 23.5 is some magic physical boundary just because that's the northern extent of the sun's latitudinal cycle.

So the Wiki article as you read it appears to be saying the temperate climates are only 35° and 66.5°, only a subsection of the middle latitudes.  But honestly, exactly what you classify the boundaries as is sort of like arguing over which states are in the Midwest or Southern Southern US -- very unnecessary outside of very specific circumstances, and prone to at least occasional dispute probably even among experts.  Yes, a teacher or test may ask you to know their specific definition (whether of temperate boundaries or of which states are in the Midwest)... that's just part of life sometimes.

But the real take-home idea towards understanding how the Earth and specifically climate/weather work is just that there's a Polar region which has very cold polar air basically year-round, a Tropical region which has very warm Tropical air year-round (outside of colder mountains!), and then a "battle ground" that shifts seasonally and even daily in between, altering the weather significantly in those locations.  And local factors like bodies of water and wind regimes can significantly shift regions into a large array of different expected weather


This is an important and pertinent question to help understand the 'late veneer' process on Earth.  To do so, understanding how it may have occurred, if at all, on the other terrestrial planets (Mercury, Venus, Mars and possibly the Moon, even possibly the rocky moons of other planets).  If there is no evidence, then that sheds light on another aspect of the uniqueness of Earth.

For practical reasons, my answer will focus on Mars and Venus, as according to an article specific on the topic, Dynamical and collisional constraints on a stochastic
late veneer on the terrestrial planets (Raymond et al. 2013), that asserts that the late veneer was

  an accretionary phase for Venus, Earth and Mars but an
  erosive phase for Mercury and the Moon.

There are obvious difficulties in fully answering this question; however, Raymond et al. assert that evidence exists of 'late veneer' like activity for not only the Earth, but for the Moon and Mars, from the article:

  Evidence for the late veneer comes from the existence of highly-siderophile
  elements (HSEs) in the mantles of Earth, Mars and the Moon. Simply put,
  HSEs are “iron-loving” elements that tend to partition into metal and should
  thus be removed from a planet’s mantle during core formation.

Mantle samples are taken from Martian meteorites that have landed on the Earth and are detailed in the paper Evolution of the martian mantle inferred from the $^{187}Re$–$^{187}Os$ isotope and highly siderophile element abundance systematics of shergottite meteorites (Brandon et al. 2012) who observe the observations made by Raymond et al. as

  The
  measured concentration of HSEs in the Martian mantle is similar to the
  Earth’s (Walker, 2009; Brandon et al., 2012).

Based on a conclusion made by Brandon et al. that

  The relatively high HSE abundances in both planetary mantles likely cannot be accounted for by high pressure–temperature metal–silicate partitioning at the bases of magma oceans, as has been suggested for Earth. If the HSE were instead supplied by late accretion, this event must have occurred prior to the crystallization of the last martian magma ocean.

According to Raymond et al. the situation for for Venus and Mercury, the late veneer is modeled to have possibly affected their retrograde motion, but the authors admit that this is is speculative.

In the absence of sufficient samples from Mercury and Venus, it is modeling rather than sampling that the authors use to hypothesise the possible effect of the Late Veneer on them.  Given Venus' size, it is likely that it, alongside Earth were the 'primary targets' of the late veneer bombardment.

  Additional references:

  Walker, R. J. 2009. Highly siderophile elements in the Earth, Moon and
  Mars: Update and implications for planetary accretion and
  differentiation. Chemie der Erde / Geochemistry 69, 101–125.

  Walker, R. J., M. F. Horan, C. K. Shearer, and J. J. Papike 2004. Low
  abundances of highly siderophile elements in the lunar mantle:
  evidence for prolonged late accretion. Earth and Planetary Science
  Letters 224, 399–413.


How do geologists measure green house gass emmissions from large regions

Tracking atmospheric species over the entire planet really is comparatively easy via satellites, compared to plastering entire swathes of land with measurement stations.
You make one infrared image from an imaging satellite at the right wavelength and you got the entire country covered. The right wavelength to choose has to be

originating from the molecule in emission at the right altitude and
be optically thin. If you know your emission is optically thin, the flux in your image is directly proportional to the mass that is emitting this flux. If it's not optically thin, complications apply, but the idea is the same.

An example of the observational fleet that NASA has in orbit can be found here (scroll down the page). There it also becomes clear, that various instruments are needed to cover the entire range of interesting atmospheric species, which necessitates a number of observation platforms/satellites.


How does the changing seasons affect the large scale easterly flow of the ITCZ?

I hope I can explain this well! I will focus my answer on the ITCZ in the Pacific Ocean. The first point is that the Coriolis force is zero at the equator and maximum at the poles (1). So, another factor comes into play "the walker circulation which is strongly tied to El Niño–Southern Oscillation (ENSO). ENSO states are 3: normal conditions, La Niña, and El Niño.
Given that Coriolis force is minimal around the equator, other wind drivers are more important. El Niño (La Niña) occurs when the tropical Sea surface Temperature (SST) in the central and eastern Pacific ocean is warmer (cooler) than the multi-decadal climate average. During normal conditions, higher pressure over the southeastern Pacific and lower pressure over the western Pacific drive easterly trade winds along the equator (known as Walker circulation), resulting in cold water upwelling and dry weather in the eastern Pacific. When the easterly trades are exceptionally strong, the eastern Pacific becomes colder and drier, resulting in La Niña conditions. The last case, El Niño occurs if the pressure over the eastern Pacific decreases: then easterly winds weaken or reverse direction, leading to a stronger ocean countercurrent that carries warm water into the eastern Pacific beside wetter weather conditions (Ahrens, 2009; Stull, 2018). So during El Niño events, the winds are not always easterlies( heading west) in the western Pacific they are westerlies, and in the eastern Pacific are easterlies. And keep in mind that the ITCZ is strongly linked to warm SST. That is why the ITCZ reaches the northernmost location in September (same as warm SST), although the Solar insolation peak in mid boreal summer (July).
I hope this answers the question. late better than never ;-)


Relationship between tides and earthquakes

I don't find Ide et al's recent paper to be very convincing. They only studied three earthquakes - hardly a statistically representative sample. There are millions of earthquakes on record, and hundreds of really big ones, of more than about MM 7.0, so there is plenty of scope for a more rigorous study. They occur at all phases of the tides. Some have claimed a weak correlation between tidal maxima and earthquake occurrence, but these are only just detectable above randomness, so maybe tides have an influence, albeit very small. The additional shear stress caused by tides is 2 to 3 orders of magnitude less than the stress release of an earthquake, so clearly other factors are much more important, such as the extent and location of fluid lubrication, and heterogeneity of friction along the slip plane.


How to convert soil moisture units from meteorological model?

Your method looks OK, however, water density varies with temperature.

Not knowing exactly what your aim is or how accurate/fussy you want to be, you may want to consider using the density of water for its temperature rather than accepted average of $1000 kg/m^3$.


Why is there a daily inequality for low tides?

The water for high tides needs to come from somewhere; the mean sea level should stay approximately constant, as long as wind is neglected. That way tides are a kind of oscillations.

In the first of the two diagrams a low low tide is followed by a high high tide, and a high low tide is followed by a low high tide. That way the mean sea level, averaged over one low tide - high tide period remains constant:

In the second diagram you need to average over two low tide - high tide periods to get a constant mean:

The first diagram can be explained by the superposition of semi-diurnal tides, while
the second diagram needs an additional diurnal constituent. Depending on the amplitude and phase shift of the diurnal constituent relative to the semi-diurnal constituent we can get different resulting oscillations.

More about tides and their constituents.


What determines the spectrum of high and low frequency waves emitted by an earthquake?

There are several factors that determine the spectrum of wave frequencies of earthquakes. They include the following:

1) Size of the earthquake. All other things being equal, the larger the earthquake, the larger the spectrum of frequencies.

2) The texture of the rocks or other materials. Hard materials have a wider range of frequencies than soft materials.

3) The ratio of "body" to surface waves. Waves emanating from the body of the earthquake have higher total frequencies (and greater variation), than waves emanating from the surface of the ground.


Aren’t photons the vector for energy input to earth?

Photons do not emit energy but rather, carry stored kinetic energy that has the potential to give or TAKE AWAY heat so, to answer your question, they ARE an energy vector but would think they are not the fuel for the Carbon Cycle since they get scattered by particles and water vapour....which leads me to think they are part of the cocktail, but not the fuel in itself. Here is an excellent visual and summarized source for interactions of radiation with the atmosphere > https://www.nrcan.gc.ca/maps-tools-publications/satellite-imagery-air-photos/remote-sensing-tutorials/introduction/interactions-atmosphere/14635

I believe you have asked an excellent question and look forward to reading the subsequent responses.


How could humans alter storm intensity or direction other than cloud seeding?

There are numerous ways. Arguably, some we are already doing, but are not intended (such as urbanization and the emission of different pollutants). But I'll suppose you are wondering about intentional modifications. Moreover, this is perhaps too general of a question, as there are a variety of different types of storms, of varying sizes. I'll tackle what I can, in a reasonable fashion. And for the sake of argument, I'll just ignore the downsides.

Let me repeat that, I will ignore the downsides. This may yield a comedic effect.

Extratropical cyclones.

Being that these take the energy from baroclinicity, a good way of disrupting the intensity of these storms is to warm the cold area and cool the warm area. You can do whatever you want to do to accomplish that, be it drop a couple megaton nuclear bombs in the cold region, etc.

Tornadoes

One thing you need to know about tornadoes is that the storms that generate these rely on stability/buoyancy and shear. Leveling everything should reduce the shear. Covering the surface with ice should also promote a more stable atmosphere.

Hurricanes

Hurricanes derive much of their energy from the temperature and entropy difference between the surface and the tropopause. Also, increasing the drag can reduce the wind speed. Different ways to do these can be found in NOAA.

Certainly these aren't all the ways that the weather can be modified. But these are just some. Of course, anything we do may backfire. Extratropical cyclones serve a purpose-transporting energy and momentum. Even hurricanes move water vapor towards the poles. And to that, I'll quote Jeff Goldblum:

  ...[Y]our scientists were so preoccupied with whether or not they could that they didn't stop to think if they should.


What is the source of the Big Sur river?

This is the response I received after asking a friend who works as an Hydrologist:

  The river is fed by ground water that is slowly leaking out of the base of the mountains. Rain water slowly percolates through the (elevated) soil, which is why the river still runs many months after the rainy season.

Note to other prospective respondents: if you have a more technical/accurate answer to my question, I am still curious about the mechanics of this process, and am  will mark yours as the correct answer.