What is the relationship between the derivatives of specific volume and potential temperature with height?

$$\theta=T\left(\frac{P_0}{P}\right)^\frac{R_d}{c_p} \tag{1}$$
$$\alpha=R_d T P^{-1} \tag{2}$$
$$\frac{\partial P}{\partial z}=-\rho g \tag{3}$$

It can be shown that $$\frac{\partial \theta}{\partial z}=\frac{\theta}{T}(\frac{\partial T}{\partial z}+\frac{g}{c_p }) \tag{4}$$

Therefore $$\frac{1}{\theta}\frac{\partial \theta}{\partial z}=\frac{1}{T}(\frac{\partial T}{\partial z}+\frac{g}{c_p })\tag{5}$$

So if we take $\frac{\partial \alpha}{\partial z}$, we find $$\frac{\partial \alpha}{\partial z}=R_dP^{-1}\frac{\partial T}{\partial z}-R_dTP^{-2}\frac{\partial P}{\partial z}\tag{6}$$

Then we can rewrite (6) using (2):

$$\frac{\partial \alpha}{\partial z}=\frac{\alpha}{T}\frac{\partial T}{\partial z}-\alpha P^{-1}\frac{\partial P}{\partial z}\tag{7}$$

Divide by $\alpha$ $$\frac{1}{\alpha}\frac{\partial \alpha}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}- P^{-1}\frac{\partial P}{\partial z}\tag{8}$$

Employing (3) $$\frac{1}{\alpha}\frac{\partial \alpha}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}+ P^{-1}\rho g\tag{9}$$

Which is the equivalent of

Employing (3) $$\frac{1}{\alpha}\frac{\partial \alpha}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}+ P^{-1}\alpha^{-1} g\tag{10}$$

Now, it may get a little sketchy in this derivation. But we're close. Assuming an adiabatic transformation ($dH=c_p dT-Pd\alpha=0$ and $H-H_0=c_pT-P\alpha$), we can rewrite (10) to look a little funky

$$\frac{1}{\alpha}\frac{\partial \alpha}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}+ \frac{g}{H-H_0-P\alpha}\tag{11}$$

Since enthalpy is conserved, $H=H_0$

$$\frac{1}{\alpha}\frac{\partial \alpha}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}+ \frac{g}{c_p T}\tag{12}$$

And finally,

$$\therefore \frac{1}{\alpha}\frac{\partial \alpha}{\partial z}=\frac{1}{T}\left(\frac{\partial \alpha}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}+ \frac{g}{c_p}\right)=\frac{1}{\theta}\frac{\partial \theta}{\partial z}$$


Does "atmospheric forcing" have a stated definition?

The example that you've linked to (Larsen, 2003, "An investigation of the Faroe Shelf Front", Univ. of Bergen) is a description of various processes that contribute to the existence and variability of an ocean front around the Faroe Isles.  As an oceanography thesis, it's mainly concerned with the ocean state (e.g., temperature, salinity) and local, internal process that affect the front.  But the introduction also mentions external process that affect the local ocean state, such as the wider-scale ocean state/fluxes, topography and atmospheric forcing.

You could loosely think of these three respectively as the lateral, lower and upper boundary conditions for the local block of ocean of interest around the Faroes. In this context it could also be phrased as the forcing of the ocean by the atmosphere, so how the ocean is affected by the exchange with the atmosphere of quantities such as heat, water and momentum.  Larsen summarizes these through descriptions of air temperature and heat flux, precipitation, evaporation and runoff, and wind speed and direction.

Often when we're interested in a particular physical realm (e.g., atmosphere, ocean, land or ice-sheets) we prescribe (i.e., force) the interactions it has with the other realms to make it easier to investigate processes within the realm.


If you are smelling something, you are inhaling gases, particles, or a combination of the two.  They don't normally build up in the atmosphere because of three reasons:  transport/dilution (which you mentioned), chemistry, and deposition.  Yes there is plenty of fresh air out there but as you say, over billions of years there would be a lot of accumulation of odorous compounds if it weren't going somewhere.  Though, stinky air does get trapped near the ground sometimes during stagnation events, caused by a temperature inversion close to the surface which prevents mixing with the upper air.

Atmospheric chemistry usually involves the hydroxyl radical (OH) in some way.  Rapid chemical conversions of gases often depends on OH, which is cycling and replenished thanks to the abundance of oxygen and water vapor in the atmosphere.  Many gaseous pollutants will go through a series of chemical reactions with OH, other chemicals, and/or sunlight.  They are then converted to simpler chemicals that we don't really smell.  Most odorous pollutants are chemically converted quickly (e.g. hours, days).  Some pollutants do take years to convert (e.g. methane) and so accumulate in the atmosphere.  We don't smell them, though, because our ability to "smell" things is limited to organic compounds and other molecules like hydrogen sulfide and ammonia (see here).

Deposition of air pollutants is dominated by precipitation, whereby rain can scavenge particles and chemically react with gases.  The rain deposits the pollutants (usually in a modified form) onto the surface of the Earth.  Dry deposition also occurs, especially with "sticky" compounds like ammonia.  However, dry deposition is not nearly as efficient as wet deposition.  Though, if particles are large enough, they will settle out of the atmosphere relatively quickly and deposit on the surface.

I suggest you read up a little on the topic here to get you more familiar with the different factors that affect air pollutants.


First, you need a phase diagram that goes to higher pressure. The pressure at the inner/outer core boundary is over 300 GPa. The one in the question would only get us into the mantle:

(link to source)

A typical temperature and pressure at the outermost part of the core would be 3750K and 135GPa, which is in the liquid region of the phase diagram.

For more data on pressure and temperature as a function of depth see this University of Arizona source.  All appropriate credit to Marcus Origlieri.


According to Wikipedia and Nature.com, "R Horizon" is the official letter for bedrock.

CAPTION: Example soil with designations that communicate the soil formation processes occurring in each horizon.


What are today's methods in calculating the Local Magnitude of earthquakes?

According to the equation for local magnitude calculation I give my answer: Of course there is a lot of algorithms for auto-picking, in fact, the magnitude value that you see in the first report (immediately) after an earthquake is (almost always) an automatic calculation. https://academic.oup.com/gji/article/199/1/368/731808. However, the P and S picked time is checked but humans in order to improve the accuracy. I think the human verification is always necessary and obligatory, because some earthquake are complex signals. !. Moreover, the point here is not the human-based method, I thing it should be focused on the quality control system.


Can earthquakes contribute to Antarctic ice loss?

There are two ways in which earthquakes could affect the Antarctic ice sheet, either by occurring on the Antarctic continent or by occurring elsewhere and sending tsunami-type waves towards the ice sheet/continent.

Seismic activity occurs all the time on Antarctica. Particularly the West-Antarctic Ice Sheet (WAIS) is located over seismically active zones although such occur under the East Antarctic Ice Sheet (EAIS) as well. In the case of WAIS, subglacial volcanoes have been inferred from geophysical measurements. It is possible that such activity but also elevated geothermal heat fluxes, typical of seismically active areas, contribute to making the subglacial thermal regime temperate (at the melting temperature). This means the ice flow can, at least partially decouple from the bed and slide causing larger ice fluxes. Such behaviour is known from WAIS but is observed to be a part of the dynamic setup of the ice sheet and does not seem to change fluxes on time frames that we can observe directly or through investigations of indirect evidence of past flow variations. In short, there is no clear evidence that seismic activity in Antarctica directly causes major changes in ice loss.

Tsunamis reaching Antarctica could conceivably cause break off of larger ice bergs or larger numbers of ice bergs at the fringes of the ice sheet. Ice berg calving in Antarctica is largely through ice shelves, which are floating parts of the ice sheet. These ice shelves are part of the natural way in which the ice sheet looses mass so a momentary acceleration due to tsunami-type waves is conceivable. But, the main question will be of this momentary acceleration of calving simply causes ice that would calve anyway within some period is shed more quickly resulting in a period of quiescence as the shelf recuperates and resumes normal "operations*. This is unclear because we are dealing with processes that have to be seen over long time spans. The loss of an immense ice berg, such as occasionally reported in media, may not have that much significance in the long-term.

There are studies indicating larger ice fluxes out from specific outlets in Antarctica. How these may be influenced by direct or indirect seismic activity has not been investigated. Ice in glaciers and ice sheets behaves plasticly, which means it can accommodate external forcing to some extent by plastic deformation, and also elastically. As an example, lake ice may bend when waves propagate in the underlying water but can also cause breakage under certain circumstances (wave amplitude and frequency). It is hence conceivable that increased breakage can occur if circumstances are just right but it is not at all clear that such activity would cause anything but momentary acceleration of processes that would be shadowed by the longer term trends caused by climatic forcing.


The calculation of UV indices requires some effort.

Because different wavelengths of UV radiation have different effects on skin, to calculate the UV index you need to apply "McKinlay-Diffey" weighting factors to various wavelength components of UV radiation and then integrate (sum) those results and then divide by 25.

The procedure does not use ozone readings but it does use elevation and cloud cover.

The following two references list the procedure required:

Smithsonian Environmental Research Center
US EPA
NOAA-EPA Brewer Network


Here is a nice picture from Ashok & Yamagata (2009):

It seems like the Kelvin wave is held back for some reason that I am not familiar with. From the figure below it looks analogous to a standing wave vs a freely propagating wave.  Interestingly, some authors argue that the frequency of these events has increased in recent years for anthropogenic reasons. i.e. climate change.

  a, An El Niño event is produced when the easterly winds weaken; sometimes, in the west, westerlies prevail. This condition is
  categorized by warmer than normal sea surface temperatures (SSTs) in
  the east of the ocean, and is associated with alterations in the
  thermocline and in the atmospheric circulation that make the east
  wetter and the west drier. b, An El Niño Modoki event is an
  anomalous condition of a distinctly different kind. The warmest SSTs
  occur in the central Pacific, flanked by colder waters to the east and
  west, and are associated with distinct patterns of atmospheric
  convection. c, d, The opposite (La Niña) phases of the El Niño
  and El Niño Modoki respectively. Yeh et al.3 argue that the increasing
  frequency of the Modoki condition is due to anthropogenic warming, and
  that these events in the central Pacific will occur more frequently if
  global warming increases.

The most concise definition i found is:

  The peak warming of the sea surface temperature anomaly (SSTA) is confined to the  central equatorial Pacific until boreal winter instead of propagating to the east.

You may already be familiar with this paper, but I found this passage interesting:

  Because of the obvious distinction from the traditional El Niño
  [Rasmusson and Carpenter, 1982] and even from that defined by NOAA in
  2003, we refer to the SSTA pattern observed in 2004, namely, warming
  in the central Pacific (∼NINO4 region) flanked by colder SSTA to the
  west and east, as an El Niño Modoki (pseudo-El Niño) event; this term
  is now popular in Japan and east Asia. (The word Modoki was introduced
  by T. Yamagata during 2004 while explaining a probable cause behind
  the abnormal summer climatic conditions over Japan. It has been often
  used since then by various Japanese Mass Media. “Modoki” is a
  classical Japanese word which means “similar but different.” A news
  article also appeared in The Japan Times on 24 July 2004 under the
  heading “'Mock El Niño' culprit behind heat wave, floods: Professor,”
  which follows: “The heat wave and floods in various parts of Japan are
  being caused by an El Niño-like phenomenon in the central Pacific
  Ocean, a Japanese researcher said Friday. Toshio Yamagata, a professor
  at the University of Tokyo specializing in climate dynamics, said an
  increase in the sea surface temperature has activated convection
  currents and promoted a high-pressure ridge in the Pacific, bringing a
  hot summer to Japan …”

(Ashok et al. 2007)


Is the Arctic ice dissapearing faster than IPCC models say?

The IPCC said "Although the Hadley Centre climate model underestimates sea-ice extent and thickness, the trends of the two models are similar. Both models predict continued decreases in sea-ice thickness and extent (Vinnikov et al., 1999), so that  by 2050, sea-ice extent is reduced to about 80% of area it covered at the mid-20th century."
The graph on this IPCC page shows a predicted decline in annual average extent of about half a million km$^2$ from 2000 to now. Your monthly average graph shows a somewhat faster decline over this period.

The SA article talks about the much more drastic decline in minimum (September) extent.

I can't find any IPCC prediction of minimums, so you could say the IPCC failed to predict it or you could say it's in accord with what the IPCC did predict about annual averages.

Ice volume is also declining rapidly.


Is it possible to estimate the size of a meteorite from its remains?

Meteors enter the atmosphere at speeds ranging from 11 km/sec, to 72 km/sec. Those speeds are so large that if a meteorite were to hit the surface at that speed, the energy released would be more then enough to to vaporize the meteorite on impact, therefore leaving nothing of the original impacting body. However, during their fall, meteorites slow down due to the friction with the atmosphere. The friction is proportional to the square of the meteorite radius (its cross-section), but the mass is proportional to the cube of the radius (its volume). This means that the larger the meteorite the less it slows down and the faster it hits the surface.

Past a given size, the atmosphere doesn't provide enough breaking power. Therefore, all meteorites larger than that limit vaporize during the impact. To have a sense of how big is that size limit you can simply have a look of the larger meteorite on Earth: the Hoba meteorite.

(image taken from TripAdvisor and submitted by user huys25)

Therefore, what your picture shows is not a meteorite (there would be also other reasons beside the size to say so), nor the remains of one. The remains of large meteorites often reduce to small fragments that broke from the main body before impact, or impactites. Impactites are small pieces of rock that might contain meteorite materials but are not unaltered pieces of it.

Said that, once a meteorite is found the calculation of the original size considers the final size, the speed and angle of impact (computed from crater geometry) and the meteorite composition among other parameters.

There are many online calculators that allow you to have a rough estimate of the size of a crater that a meteorite like that would leave. For example the Convertalot Asteroid Impact Calculator. From the picture it looks like porous rock, so plugging in a density of 1.5 g/cm$^3$ and impact angle of 45°, a fairly low speed of 20 m/s, and a diameter of 20 m, it would have produced an impact crater 177 meters in diameter and 44 meters deep. Definitely a landscape feature difficult to miss.

Finally, from the shape of what you show in the picture, I don't see how it can be associated to a meteorite, as it doesn't look like one at all. In that line, it could resemble the central peak of an impact crater. Like the one visible at the center of Tycho crater on the Moon.

(Image source: Wikipedia - Tycho crater on the Moon: mosaic of images, made by Lunar Reconnaissance Orbiter. Width of the image is 120 km.)

However, if the central peak were that well preserved you would expect the rim of the crater to be well preserved too, and from what you say, that doesn't seem to be the case.


The mean is probably the average cloud cover in percentages: 41% cloud coverage on average over time. The categories you mentioned: 'clear', 'scattered', 'broken' and 'overcast' are defined in different ways sometimes. Basically there is a human observing the sky analyzing the coverage in oktas or tenths (e.g. 6/8), or more likely there is a sounding device looking through the sky and getting a value in percentages of the cloud cover (e.g. 75.0%). To get one of these categories from the device data, the percentages are turned into oktas or tenths. Some data is lost in this transformation and thus from the categorized data it is impossible to get calculate the actual mean.

Some use more the oktas (World Meteorological Organization) and others (I would guess often USA) tenths in the categorization. Also after quick googling the categorization bins seem to be differ from source to source at least for the ones who use tenths. The clear and overcast bins are for all the same less than 1/8 or 1/10 and more than 7/8 or 9/10 respectively. Obscured also always means basically that the value is undetermined: perhaps there is fog and the device doesn't get the responses it would've wanted. Some have also a category 'few', but since it was not present in the data they have used a categorization that doesn't include it.

Based on all above I would guess the categorization is the same as in this webpage. Categories are clear: less than 1/10, scattered: 1/10 to 5/10, broken: 6/10 to 9/10 and overcast: over 9/10. As the tabulated values are historical they give a climatological average of what are the possibilities of different cloud cover scenarios. I would suspect that clear and scattered scenarios are good enough for watching an eclipse so e.g. in Salem you would have a 32.2 + 19 = 51.2 percent chance to have a decent or better viewing conditions.


How are low pressure zones tracked across the ocean?

It is a combination of points 1,2 and 4.
Ships
Ships can provide observations, but they are generally confined to shipping lanes rather than distributed all over the oceans.   NOAA operates a volunteer observing program and you can find recent ship obs here.  The ships can report location, wind direction, wind speed, pressure, pressure tendency, air temperature, water temperature, dew point, wave information and a few other fields.  Not all ships report all of the data, but pressure is generally reported by all ships participating.
Buoys
NOAA operates a global buoy network though these are generally located in coastal regions.  There are regions of regularly spaced buoys in the ENSO regions.  There are also some buoys in the Indian Ocean (not pictured).

Drifters
The buoy network leaves vast swathes of ocean unmonitored and to get these obs NOAA uses a network of drifters that, as the name implies, drift along the ocean surface.

The blue points in the map above are drifters than can report sea level pressure.
Summary
Weather models that assimilate these observations will use sophisticated algorithms to "fill in the gaps" and produce a continuous field of global sea level pressure.
Aircraft can report pressure, but knowing pressure at altitude won't yield sea level pressure without knowing (or making assumptions) about the state of the atmosphere between the airplane and the surface.  Upper air observations are good though, and quite important to forecasting and generally much more sparse than ocean surface observations are.


Will geothermal cooling be greatly affected by global warming?

I presume that by geothermal cooling you mean geothermal energy. Yes, it's an attractive option and is used a lot in Iceland, but unfortunately there are not many places that have such easy access to it as Iceland. Geothermal energy will be just one source of non-polluting energy, along with hydro-electricity and many others. Today's global warming is just a passing phase, and will be followed sooner or later by another ice age.

The Earth is gradually cooling as geothermal heat is lost into space and the crust is getting thicker, as has already happened on Mars, but this will have no noticeable effect on Earth for many millions of years, by which time we will have gone to join the dinosaurs.


Firstly, the RSS and UAH datasets do not "line up nearly perfectly", the diagram below shows both products over the last 20 years (which appears to be what this question is actually about) here is the url used to generate it.

As you can see, they disagree quite considerable on the value of the trend.  UAH and RSS are different methods used to infer trophospheric temperatures from them MSU instrument carried aboard various weather satellites.  The reason why they differ is because they use different methods to deal with the various drifts and biases involved in the measurements, and the fact that we don't know exactly how this is best performed is what is known as structural uncertainty.  Note there are a couple of other similar products, but UAH and RSS are the main ones.

As to "no significant warming for over 20 years", this is the subject of a fair bit of discussion in the journals, but not nearly as much as in the blogsphere, and a lot of it stems from not understanding what the term "statistically significant" means (and more importantly, what it doesn't mean).  The key point is that "no significant warming" does not mean "there has been no warming" or that "the rate of warming has slowed".  Unfortunately the reasons for this are a little complicated, so I will start with a simple example.

Consider the usual statistical test for the bias of a coin, we start by stating the null and alternative hypotheses:

$H_0$ - null hypothesis, unbiased coin, probability of a head = p - 0.5.

$H_1$ - alternative hypothesis, biased coin, $p \neq 0.5$.

We then flip the coin $n$ times and count the number of heads, if the p-value is less than some pre-determined value, typically $\alpha = 0.05$, then we say that we can "reject the null hypothesis", implying that the data provides some support for our alternative hypothesis, $H_1$.

However, if we are unable to reject $H_0$, there are at least two reasons for this, it may be that $H_0$ is true, or it may be that $H_0$ is false but we haven't seen enough data yet to be confident of this.  For example, if we only toss the coin four times, then even if we get a head every time, we still won't be able to reject the null hypothesis as the p-value cannot be smaller than 0.0625.

The statistical power is the probability [in a frequentist sense] that the test correctly rejects the null hypothesis ($H_0$) when the alternative hypothesis ($H_1$) is true.  In this case, the statistical power of the test with only four flips is zero, because we can never reject $H_0$.

So, if you want to claim that it is in some way a surprise that we can't reject the null hypothesis, you need to show that the power of the test is high, and in the case of the trends over the last 20 years, it isn't particularly high, as similar trendless periods ocurr both in the observations and in the model output, as shown by Easterling and Wehner.  For example the trend in RSS to 1997 is very similar to the trend from 1995 to the present day, and that is almost as long:

Part of the reason for this is that the RSS and UAH datasets are both very sensitive to ENSO, and the trend over the last 20 years is dominated by the 1998 El-Nino.

So how long do you need to get reasonable statistical power?  Well climatologists generally use a period of at least thirty years (IIRC this is a WMO guideline).  Santer el al performed a study and found that you would need at least 17 years of data for identifying human impacts on surface temperatures.  Note this is a bare minimum, and refers to the detection of a trend in a randomly chosen time period.  If you wait until a period of 17 years comes a long before making the argument for a hiatus, the assumptions of that analysis are violated by the fact that multiple hypothesis tests are being implicitly performed, and in practice you would need a much longer period.

Now are scientists ignoring the apparent "hiatus"?  No, there have been many studies analysing it, for instance Foster and Rahmstorf show that the apparent hiatus can be reasonably explained by ENSO and volcanic forcing, and so there is no real reason to suppose that there has been a pause in anthropogenic global warming, and the apparent hiatus is probably due to a redistribution of heat between the atmosphere and oceans.  There has even been a special issue of Nature Geosciences devoted to this topic.

UPDATE: @user1286792 notes in the comments below: "!UAH, and !RSS show it has been 21.5 years since there has been any tropospheric warming.".  This clearly isn't true, at least for UAH.  If you plot the trend since 1995, it is essentially the same as the long term trend since the start of the dataset.  The fact that the RSS trend for the last 20 years is very different is I suspect the reason skeptic blogs switched from using UAH to RSS, but as always don't believe everything you read on line, and woodfortrees is a great tool for checking things.  As I said, UAH and RSS vary considerably over the last 20 years in their trends and the reason for this is structural uncertainty.  That doesn't mean that either of them are right or wrong and if your argument is not valid for both, then you probably shouldn't be confident that it is true.  Basically the timescale is too short to reliably estimate the trend given the uncertainties in the data, including the structural uncertainties.

Caveat: I think WFT may be using a previous version of UAH, however this rather illustrates my point about the structural uncertainties, if successive updates to the algorithm make such large differences to the trends, that means the structural uncertainties are very large and we should take that into account when looking at the trends.  However, the basic point remains that (i) the trends are too short to expect the warming to be significant (ii) the apparent haitus is adequately explained by ENSO and volcanic forcing (iii) similar periods of little warming are seen in the output of GCMs, and so it is not entirely unexpected.


Would the oceans have boiled off if life (cyanobacteria) hadn't evolved on Earth?

Short answer: no. The life does contribute to the amount of CO2 in the atmosphere and the temperature on the Earth but mostly not by photosynthetic organisms.

The main mechanism, which regulates the temperature and removes CO2 from the atmosphere is silicate and carbonate weathering cycle. In simple model the more CO2 you have in the atmosphere, the more acidic is rain water. More acidic rain can dissolve more of silicate and carbonate minerals and the dissolved minerals are carried to the ocean, where they either precipitate or are used by living organisms to create shells of CaCO3 (calcite) or SiO2 (opal). When these organisms die, many shells are dissolved but some shells fall all the way to the sea floor and are buried.

In simple words: more CO2 -> more (acidic) rain -> more weathering and C02 removal -> more mineral deposits -> less CO2 in the atmosphere -> lower temperature -> less rain

If you want more information with formulas, I suggest looking up for description of carbonate–silicate geochemical cycle.


Could one say that granites are metamorphic rocks, or not at all?

This is the key:

  used to be part

It is important to look at this from a historical point of view. Up until the 1950s and early 1960s, there was no agreement to how granites form. This became the granite controversy.

On the one hand, experimental work showed that granites crystallise from magma, but this magma had to be derived from basalt-like magmas. This led to two problems:

Where is all the basalt from which the granite was supposed to form?
What happened to all the rock that was there before the granite (aka the "room problem")?

This led people to think that granites formed by metasomatic replacement of other rocks. Essentially, you have other things than were not granite and then they were transformed to granite through various geological process, without ever crystallising from magmas. This is what people say when they talk about granites as metamorphic rocks.

But, this is not the case and later research demonstrated that granites from by crystallisation of magma and the process of metamorphic formation of granites (by metasomatism, or "granitisation") does not actually exists. There were (and still are) many questions left unanswered on exactly how this happens, but we know that this does happen and granites are indeed igneous rocks. In fact, there's a great paper published just this week in the journal Nature, showing modelling of how some of these things can form.

Nevertheless, granite formed can be sometimes related to metamorphism. Extreme cases of hot metamorphic can cause melting of (previously sedimentary and then metamorphic) rocks to form magma that eventually crystallises as granites. This is known as migmatisation, and is commonly used to explain the widespread occurrence of "leucogranites" in the Himalayas for example.

Additionally, some high-grade metamorphic rocks contain quartz, feldspars, micas, and amphiboles. The metamorphic texture (foliation and lineation) is not always obvious, making it easy to mistake metamorphic gneisses as igneous granites.


There are various plate tectonic models around, that are able to provide insight in paleobathymetry and -altimetry. These models include information on sea floor spreading and subduction, which provides much information on bathymetry. Also plate tectonic movement largely drives the uplift of mountain ranges, and combining this with isostatic effects of sediment loading, glaciation, etc. you can get a fair picture of paleoaltimetry as well. Of course this method provides only relatively low resolution data, and to get more detailed maps you need more localised data.

Outcrops and bore holes provide much information on the depositional environment, and for example sequence stratigraphy is a tool that can be used to predict/retrodict regional environments. If you know from a number of locations where the coastline was relative to its current position, and know from models etc. where the sampling locations were in the past you can map paleocoastlines as well.

So to answer your question shortly, yes there is a lot of global information available by combining large scale models and local investigations, and where such information is missing you can at least provide an educated guess of coastal positions.


What percent of the Earth's core is uranium?

Good question! Geochemists and geophysicists agree to disagree, sometimes quite strongly. There are also disagreements within each group as well as between the two groups.
It's not just uranium. There are four isotopes whose half-lives are long enough that they can be primordial and whose half-lives are not so long that they don't produce much heat. These four isotopes are

Uranium 235, with a half-life of 0.703 billion years,
Potassium 40, with a half-life of 1.277 billion years,
Uranium 238, with a half-life of 4.468 billion years, and
Thorium 232, with a half-life of 14.056 billion years.

The consensus view amongst geochemists is that there is very little, if any, of any of these isotopes in the Earth's core. Potassium, thorium, and uranium are chemically active. They readily oxidize. In fact, they readily combine chemically with lots other elements -- but not iron. They are strongly lithophilic elements. Moreover, all three are "incompatible" elements. In a partial melt, they have a strong affinity to stay in the molten state. This means that relative to solar system abundances, all three of these elements should be strongly enhanced in the Earth's crust, slightly depleted in the Earth's mantle, and strongly depleted in the Earth's core.
Geophysicists look at the amount of heat needed to drive the Earth's magnetic field, and at the recent results from neutrino observations. From their perspective, the amount of residual heat from the Earth's formation is not near enough to drive the geomagneto. The growth of the Earth's inner core creates some heat, but not near enough to sustain the geodynamo. Geophysicists want a good amount of heat flux across the core mantle boundary to sustain the geodynamo, and to them the only viable source is radioactivity. Recent geoneutrino experiments appear to rule out uranium or thorium in the Earth's core, but not potassium 40. The neutrinos generated from the decay of potassium 40 are not detectable using current technology.


Global scale seismology experiments / observations disproving flat earth conspiracy?

As you rightly say, seismicity is one geological proof of an almost spherical planet, but surely it is far easier to prove your case by satellite data, such as scenes from http://weather.msfc.nasa.gov/GOES/ Irrespective of the position of the satellite, the Earth always appears as a disc, never 'edge on'. For that matter, if the Earth wasn't approximately spherical there wouldn't be any stable satellite orbits - so no satellite pictures in the first place. You could use your mathematical skills to demonstrate that the only stable orbital configuration is around a sphere. Also the consistency of gravity, at any known point on the planet's surface, points to a spherical Earth. Then there are commercial and military flights which have, over time, flown arcs along almost every conceivable great circle, without ever coming to an edge. Turning to astronomy, every stellar or planetary object large enough to form under gravity appears as a disc - never edge on - surely no coincidence..... etc. etc.

But I'm curious - why bother?! You are never going to convince the likes of creationists, climate-change deniers, 'flat earthers', and the like. They have already made up their mind, and don't want to be confused by the facts. No matter how much evidence you supply, it is like water off a duck's back to the closed mind. They are comfortable with their own warped model of reality in their head - no matter how erroneous. Paradoxically, they view the discomfort of having to adjust their world view as a form of 'cognitive dissonance'. So trying to convince flat earthers is like the proverbial 'flogging a dead horse'.


No, earthquakes are sudden, often very energetic events which produce faults and discontinuities. There is a sharp break in the strata when subjected to a powerful earthquake. The folding of strata is a much more gradual process, where rock deep underground is subjected to enormous lateral pressure over millions of years. This pressure is caused by plate movements (continental drift). Earthquakes have a variety of causes, but the most violent ones are also caused by continental drift as one plate slides past another along a fault line. The San Andreas Fault in California is an example of this. One of the plates is moving, but friction holds it in place for a while, sometimes for many years. Pressure builds up until suddenly the friction force holding it in place gives way, and there is an earthquake as the moving plate slips forward for a few metres. For these reasons, geologists have never seen a newly created fold after an earthquake. It is impossible for one to form in so short a time.


How did sand dunes appear in the midst of a fertile region?

It appears the sands at Talakad are the result of a ecological disaster that occurred in the 17th Century. At the time, a dam was constructed north of Talakad on Kaveri River which caused the river to be diverted. This exposed a sand deposit in the river which was subsequently moved to Talakad by monsoonal winds. The following quote is from this source AB Roy & MS Sethumadhav, 2014:

  It is thought to have originated due to an ‘eco-disaster’ that
  lashed the region during the 17th century. That was the
  time when the normal flow of the Kaveri River was
  impeded because of the construction of a dam on the up-
  stream side, north of Talakad and subsequent diversion of
  water in a different direction. As a result, the water level
  at the point bar on the concave side of the Kaveri meander southwest of Talakad was significantly lowered leading to the buildup of sand at this place. The accumulated
  sand was then actively reworked and carried by the
  northeasterly monsoon winds, which were subsequently
  deposited around Talakad engulfing the temples and other
  settlements in the region. The yellow coloured, uniformly fine-grained and homogeneous nature of the sand
  without any clay material in it provides further proof that
  the air-borne sand deposited as dunes


How much water does a wave transport into a sea cave?

The time-averaged material transport by water waves is quantified by Stokes drift, which is the residual Lagrangian drift due to sub-surface orbits not being closed:

$$
u_{St} = \dfrac{\omega k^2 a \cosh[2k(z+d)]}{2\sinh(kd)^2}
$$
where $\omega$ is the angular frequency, $k$ is the wavenumber, $a$ is the wave amplitude, $d$ is mean water depth, and $z$ is the displacement from water surface, positive upward.

Because the cave is closed, there is build-up of water in the cave which results in pressure gradient-induced Eulerian backflow which opposes the Stokes drift. This backflow is barotropic in nature and equals:

$$
u_E = -\dfrac{1}{d}\int_{-d}^{0}u_{St}(z)dz
$$

The transport velocity is the sum of mean Eulerian velocity and Stokes drift:

$$
u_L = u_E + u_{St}
$$

For the case of $T = 12\ s$, $a = 1\ m$, and $d = 5\ m$, the resulting transport looks like this:

Because the Stokes drift is not uniform in the vertical but compensating Eulerian backflow is, the resulting transport is into the cave in the upper 2 m, and out of the cave below that depth.

Assumptions made:

Inviscid ($\mu\nabla^2\mathbf{u}=0$), irrotational ($\nabla \times \mathbf{u} = 0$), and incompressible ($\nabla\cdot \mathbf{u}=0$) flow.
Small amplitude for the linear wave theory to hold.
All wave energy is dissipated at the cave wall (no reflection). If there is some reflection of waves out of the cave, then the Stokes drift and the corresponding Eulerian backflow would be reduced in magnitude, but the answer for the net transport would be qualitatively the same.
Shallow water dispersion relationship ($\omega^2 = gk^2d$).

And here is the Python code:

import numpy as np
import matplotlib.pyplot as plt

T = 12. # wave period [s]
d = 5.  # mean water depth [m]
a = 1.  # wave amplitude [m]
g = 9.8 # gravitational acceleration [m/s]

omega = 2*np.pi/T # angular frequency [rad/s]
k = np.sqrt(omega**2/(g*d)) # wavenumber [rad/m]

z = np.linspace(0,-d,501.) # depth array [m]
dz = -np.gradient(z) # depth increment [m]

# Stokes drift in arbitrary depth
ust = 0.5*omega*k*a**2*np.cosh(2*k*(z+d))/np.sinh(k*d)**2

# Eulerian backflow is the vertical integral of Stokes drift
ue = -np.ones(z.size)*np.sum(ust*dz)/d

fig = plt.figure(figsize=(8,6))
ax = fig.add_subplot(111,xlim=(-0.2,0.2),ylim=(5,0))
ax.tick_params(axis='both',which='major',labelsize=16)
plt.plot(ust,-z,'r-',lw=3,label='Stokes drift')
plt.plot(ue,-z,'g-',lw=3,label='Eulerian backflow')
plt.plot(ust+ue,-z,'k-',lw=3,label='Lagrangian velocity')
plt.plot([0,0],[5,0],'k--')
plt.legend(loc='lower left',shadow=True,fancybox=True)
plt.grid(True)
plt.xlabel('Velocity [m/s]',fontsize=16)
plt.ylabel('Depth [m]',fontsize=16)
plt.savefig('transport.png',dpi=100)
plt.close(fig)


What? Northern lights are *not* simply caused by energetic charged particles from the sun?

Solar wind particles directly entering the Earth's magnetosphere are not responsible for the majority of bright auroral displays. As you have found, it is magnetic reconnection that accelerates magnetospheric plasma that collides with the upper atmosphere to cause the visible aurora.

Polar rain

The Solar wind does enter the magnetosphere directly, and travels down the field lines that have their feet poleward of the main auroral oval. This is termed the polar rain¹. The particles in the polar rain are usually too low energy and low intensity to provide visible aurora, though they do produce X-rays as the particles accelerate in the atmosphere (for example, in this report of a Nasa study). On occasion, the polar rain can become energetic and intense enough to generate visible emissions, unsurprisingly termed 'polar rain aurora'².

Magnetic reconnection

Magnetic reconnection is responsible for the displays that people usually think of as the Northern Lights. The brightest aurorae typically occur on the auroral oval around midnight Magnetic Local Time (MLT). This can be seen in the results of the current OVATION model below.

The energetic electrons that cause the bright midnight aurora are generated by reconnection in the magnetotail, the portion of the Earth's magnetosphere that streams behind the Earth, dragged by the motion of the Solar wind (this is briefly mentioned in the NASA youtube videos linked in the question). We can tell this from the fact that the aurorae occur in a distinct oval around the pole.

The bright aurorae occur near the open-closed field line boundary³, toward the closed side of the boundary. Closed field lines are those that have one foot in the northern hemisphere, follow a continuous closed path through the magnetosphere and have a second (conjugate) foot in the southern hemisphere. This means that any charged particles on these field lines must originate from within the Earth's magnetosphere.

Conversely, the field lines accessible to charged particles from the Solar wind are the open field lines; it is along these field lines that polar rain occurs. These occur closer to the pole than the closed field lines, and form the dark area around the pole where the aurorae are not usually observed. The field lines are 'open' in the sense that they connect to the interplanetary magnetic field and are connected to the Earth at only one end, the other being open to the Solar wind.

An historical footnote

The idea that magnetic reconnection is the main cause of the aurorae is not a new one. I am not sure when magnetospheric sources of energetic particles, and reconnection specifically, became the dominant theory of the aurorae, but it was certainly before Dungey⁴ described the magnetospheric convection pattern in 1961.

So, why is this news in the 2010s? I would suggest that it is a case where an earlier, simpler explanation has become lodged in the public consciousness long after it has passed from being the state-of-the-art. Around the turn of the 20th century, the earliest investigations into the aurorae involved physical models of the magnetosphere and the Solar wind. These terrellas suggested that Solar wind directly caused the aurorae, but left investigators such as Kristian Birkeland unable to explain why the real aurorae did not occur over the pole itself, as the terrella model suggested they should.

Fairfield, D. H., and J. D. Scudder (1985), Polar rain: Solar coronal electrons in the Earth's magnetosphere, J. Geophys. Res., 90(A5), 4055–4068, doi:10.1029/JA090iA05p04055.
Zhang, Y., L. J. Paxton, and A. T. Y. Lui (2007), Polar rain aurora, Geophys. Res. Lett., 34, L20114, doi:10.1029/2007GL031602.
J. A. Wild et al. (2004), The location of the open-closed magnetic field line boundary in the dawn sector auroral ionosphere, Ann. Geo., 22: 3625–3639, doi:10.5194/angeo-22-3625-2004
J. W. Dungey (1961), Interplanetary Magnetic Field and the Auroral Zones, Phys. Rev. Lett. 6, 47-48, doi:10.1103/PhysRevLett.6.47


1. What is the youngest/oldest rock in the geological history of this map.

Your approach is the right one but isn't the limestone  underlain by something? Drawing the AB cross section would be of great help here, did you manage to do that?

2. What type of fold is shown on the map.

What is the definition of a syncline and does your interpretation agree with your answer to question one?
Are there any legend symbols on the map which would be used to indicate a fold?

3. Brief geological history of map

Putting all the lithologies and the deformation (Question 2) in right order would be a big part of that. After that maybe you have some ideas about a succession of claystone, limestone and mudstone


Regarding the melting glaciers and icebergs, why isn't the extra water vapor in the atmosphere mentioned in discussions of global warming?

Extra water doesn't mean extra water vapor. Even without this EXTRA water, the water vapor levels will increase, in the current warming world. As its the temperature rise that is making the water turn to vapor.

  As temperature rises, evaporation increases and more water vapour accumulates in the atmosphere. As a greenhouse gas, the water absorbs more heat, further warming the air and causing more evaporation. When CO2 is added to the atmosphere, as a greenhouse gas it has a warming effect. This causes more water to evaporate and warm the air to a higher, stabilized level. So the warming from CO2 has an amplified effect. Water vapor is infact the largest positive feedback in the climate system (Soden 2005). - Skeptical Science

Intensification of the water cycle hence, is a product of rise in temperature, rather than the water content. Of course we need water to evaporate, but the increase in the water content doesn't correlate to increased water vapor. It might play some role locally in small ponds and seasonal rivers which get dry during summers, but on a global scale with most of our evaporation occurring over oceans (86% of global evaporation), its not significant enough.

So coming to your question. First of all its not like water vapor is never mentioned -

  As global temperatures rise, the atmosphere then holds more moisture ... Therefore there is more water vapor available to fall as rain, snow. - thinkprogress.org - September 5

  Global warming is moistening the atmosphere - The Guardian - August 13

And if you notice, all the recent news about melting glaciers has been in connected to some recent developments and observations in form of published papers at reputed journals. NASA even conducted a press conference explaining their latest research, which led to a series of news articles on the topic. So, i'm quite sure if there are some significant developments in terms of water vapor research, it will make the news as well.


Why are there no crystals with 5-fold symmetry?

All unit cells are parallel-sided hexahedra. These are six sided shapes with parallel opposite sides. Their three principle angles may or may not be 90 degrees. And the three side lengths may or may not be equal. All of these unit cells can be uniformly stacked.

Using these building blocks it is only possible to produce planes of reflection, diads (axis of rotational symmetry order 2), triads, tetrads, and hexads.

For example, a cube (all sides the same length, all angles 90 degrees) has diads, triads, and tetrads; plus planes of reflection.
A hexagonal symmetry can be used with 60 / 120 degree angles.

Note that it is impossible to produce a regular arrangement of unit cells to produce a pentad (order 5 symmetry). As @Nathaniel says, this can be almost achieved using Penrose Tiles (2d mathematical constructions), and quasicrystals (real 3d materials). Quasicrystals will produce an x-ray diffraction pattern with a pentad, but the actual atoms do not follow a true 5-fold symmetry.

I suspect your confusion is over the final (macroscopic) crystal shape and the unit cell shape. These are rarely the same. (Salt being an example where they are; but diamonds, garnets, do not)


What determines the scale of columnar jointing?

There is a paper about this in the Bulletin of Volcanology (Hetényi et al. 2012).

Cooling rate seems to be the main parameter controlling column size (faster cooling yielding to thinner columns). According to the authors, cooling rate is itself controlled by two non-independent factors: (1) the geometry of the lava body, and (2) the chemical composition of the lava.

(1) Geometry of the lava body influences the boundary conditions for cooling, depending on the emplacement setting (air, host rock, ice...). In the case of a lava lake (figure 2b), lava close to the lake walls will cool faster than lava at the centre of the lake, resulting in thinner columns. Thickness also plays a major role, as shown by figure 10: thicker lava bodies cool slowly, generating thicker columns.

(2) Chemistry plays a role (figure 11): felsic (SiO2-rich) lavas tend to have thicker columns than mafic lavas. It seems a bit counter-intuitive, as felsic lavas are usually emplaced at a "low" temperature and should thus cool faster than a basalt emplaced at 1200 °C... But felsic lavas are more viscous and tend to form thicker flows -> back to (1).


Probably the best known is more recent, the 1902 eruption of Mt. Pelée on Martinique, where 30,000 people were killed by pyroclastic flows. I don't know the extent of burial - it appears that the city may have been destroyed more by the ash cloud than the dense part of the flow.


How do oases form in the middle of the desert?

Oasis are places where aquifers are connected to the surface. The source of the water in the aquifer however can be hundreds of miles away in areas that do get significant rainfall.

The trick is geologic strat have different properties; some allow water to flow easily, others are very water tight, a water accessible layer covered by a water proof layer creates a aquifer. Faults or erosion can breach this water seal allowing to water to the surface, as can human wells. Recharge areas are places at higher elevation where water can enter the aquifer and flow downhill, they can be hundreds of miles away and are often in the mountains which often get much higher rainfall.  A picture is worth a thousand words.


What are the effects of underwater "windmills"?

As you have noted, this technology is new, and so far only small numbers of experimental tidal energy converters (TECs) have been deployed. For this reason, little has been possible in the way of measurement, and so as you note, all estimates are based on models or other means of prediction.

To answer the second question first - how much the currents are affected depends how much of the energy you remove. Since the whole point of TECs is to remove energy from the flow, there must be some effect on currents. Garrett & Cummins (2005) built a simple analytic model of a channel between two large basins (which reflects many tidal energy scenarios) and showed that if all other considerations (e.g. navigation, engineering practicality) are ignored then the maximum power that may be extracted from the channel is obtained when its flow rate is reduced by approximately two thirds. However, this scenario is unlikely to ever be obtained, and the real limit on energy extraction at a given site (if not an economic limit) will probably be determined by what level of environmental effects are deemed to be acceptable. The relationship between power extracted and effect on the flow is not a simple one, and in most cases a significant proportion of the available power could be obtained with a relatively small change to the local currents.

A number of modelling studies have been made of more realistic scenarios for early deployment (e.g. Admadien et al 2012). These typically predict local changes to current speeds of up to 30%, which fade after a few km. Typically there is a decrease in the flow speed in line with the TECs, and an increase to either side of the farm/array, as some of the flow diverts around the added impedence. Effects on residual velocity (i.e. that which is left in the long term when the tidal cycles are averaged out over a period of time), which is relevant to sediment transport processes, are predicted up to at least 15km away.

Some baroclinic modelling (Yang & Wang 2013) has suggested increased mixing, and thus decreased stratification, as a result of the turbulence introduced by TECs. It is also conceivable that in other scenarios, stratification might be increased as a result of reduced flow speeds.

Physical effects, then, are likely to include direct effects on current speed, sediment, and stratification.

The obvious possible biological effect is from collisions. This is not my field, but as I understand it no effect is likely on small fish populations from collisions, although individuals may be affected. Collision risk for large animals (e.g. sharks and marine mammals)  and for diving birds is a topic of active research, and is likely (especially for mammals) to depend on their behaviour around the devices. No large animal collisions have been reported on any of the prototypes undergoing testing so far.

A good review of possible effects on benthic organisms is provided by Shields et al (2011). These may include,

Direct disruption of seabed habitats by physical interference, e.g. from moorings
Disruption of ecological niches: Some organisms have evolved to survive in areas where others cannot - e.g. high current speed environments. Changes in seabed conditions, e.g. from greater or lesser current speeds, may cause them to be out-competed by other species that can then settle there.
Similarly, changes to sediment distribution represent changes to seabed habitats.
Alteration of flow patterns could have implications for species with a dispersive juvenile stage (e.g. larvae that rely on currents to spread) or those that rely on current flow for nutrient or waste transport.


Is snow less likely to appear at a coastal area?

I don't know if someone has conducted statistical research on this. It certainly depends on the situation. Here are some situations:
More snow in coast

Like @gerrit commented, elevation increases precipitation as air is forced to lift up and thus cools condensing water vapor -> rain/snow. This is true when predominant winds are from the sea.

Lake-effect snow situations

Less snow in coast

The air temperatures are affected by nearby bodies of water so situations where temperatures are freezing, but the sea isn't frozen yet will keep the coastal temperatures higher. Thus melting falling and fallen snow faster than in inland.


Water and explosive volcanoes in the Pacific ring of fire

How is it possible for magma to contain water at such depths?

This can happen precisely because the magma is at such depths. Think of CO2 in soda or coke. When the drink is closed and pressurised, the CO2 is dissolved in the liquid. This means it's part of one physical phase. There is one "thing" that contains the liquid and the CO2 together: the CO2 is not a gas! Only when you open  the bottle, the CO2 can escape being dissolved in the liquid, and separates from the liquid as a distinct gas phase.

The same thing happens in magmas. While the magmas are pressurised at depths they have water dissolved in them. Note that this water is not separate liquid water or vapour flowing around the magma. It is inside the magma in one physical entity. Think of dissolving salt in water - you can't see salt grains but it's there. Anyway, once the magma rises it loses pressure. This causes the water to separate out from the magma into a distinct vapour phase that rises and expands rapidly, causing the explosive eruption.


What are these underwater structures near 6°N 85°55'W

As the other answer suggests, these are sonar surveys of the ocean depths. But the answer is a bit more complicated.

The vast majority of the ocean floor has never been mapped. We really only know about the water depth because the water above the sea floor is lighter than if it were rocks. So a deep ocean produces less gravity than a shallow one. And, miraculously, you can fly satellites over the oceans that pick up on how hard Earth pulls on the satellite at any given point and convert that data into an ocean depth.

This is what Google Maps and other mapping services show by default. The problem is that this information is not very accurate: That's because not just the point immediately under the satellite pulls on the satellite, but also points elsewhere. So a very steep undersea mountain will not be distinguishable from a broader but less high one. This is why in general these images of ocean depths are not shown in high resolution -- we just don't know the depth of the ocean on length scales of a few kilometers.

But then along comes the occasional ocean survey. (Think: Research ships, the ships that lay undersea cables, the ships that search for ship wrecks or the occasional plane that fell from the sky.) They tow a sonar array behind a ship, or send a side-scan sonar equipped submersible, to actually map the ocean floor on length scales of a few dozen meters. For map services, this presents a conundrum: They'd like to show the more accurate sonar data where it is available, but they need to overlay it on the low resolution maps that comes from satellites.

This is exactly what you see here: The background is the low-resolution satellite map. Overlaid is the high resolution sonar data. At the edges of the sonar maps, these two maps won't match, and so you will see the sharp edges. You can see the different resolutions if you zoom in and out of the view you showed.

(Given the long straight tracks of these sonar maps, one can guess that in your view, these were created by surveys for laying undersea cables, for example to the  Galapagos Islands.)


These are qanats, a type of antique drainage system common in arid climate regions of the Middle East, particularly in Iran (as mentioned by @Spencer @Winwaed). Some of those are still in use for storage because of lower underground temperature or to access the underground water.

In the picture posted by OP, it further make sense since the underground channels follow linear paths near, around and crossing the small stream, thus providing a remote access to water.

Here is an oblique picture showing the qanats of Bam in Iran (Higher resolution available at the source here).


What control the atmospheric lifetime of different metals in aerosols?

You could say that metals and aerosols reside in the atmosphere but I'm struggling to call that "atmospheric lifetime", which I've only heard in reference to gases.  The residence time of particulate matter is mostly a function of meteorology (e.g. PBL height, wind speed) and deposition (e.g. raining, settling velocity).  You've observed some metals that had a longer residence time.  I can think of two reasons for that:

Unique reactivity with other atmospheric components will change the mass and deposition velocity of particles.  Metals that do not react well in the atmosphere may not grow as quickly and therefore settle more slowly.
Specific metals may be used more prevalently in fireworks that obtain high altitude, such that the metal emissions are injected further up into the atmosphere and subjected to more atmospheric mixing and therefore longer settling times.

You might find this article by Licudine et al., (2012) of interest, which discusses monitoring of metals on New Years in Hawaii.


Why are clouds outlining the southeastern United States?

The small puffy clouds over Florida are cumulus clouds ('fair weather clouds' accompanying the launch). The sun heats the ground and the ground composition is not evenly distributed, where air is warmed more quickly it starts to rise until the moisture it contains condensates, forming clouds, while colder air in between sinks. This is called convection, in this case limited to the lower atmosphere over Florida.
The ocean is mostly free of them because it isn't heated as much as the land and warming is more uniformly distributed, so that in that specific weather situation (high pressure it seems) no convection did develop over water.


Is there a meaningful concept of a mountain having a footprint area?

The mountain you see is only a part of the story. From a geological view all mountains have roots, in which the weight of the mountain depresses the upper crust into the lower crust (occasionally with gravity inversion, as in salt diapirs), and the overall crust is depressed into the upper mantle. This results in a regional gravity anomaly which could be regarded as one form of the mountain footprint. That is, a map of the deviation of the mountain's 'Bouguer anomaly', away from the regional gravitational envelope.
But that's just a geophysical perspective. You could doubtless develop comparable 'footprint definitions' from a hydrologic or geomorphologic perspective.


An interesting question! I suggest you do some 'slightly complex' calculations. Look up the angular momentum of the whole Earth. Then calculate pM.dF where pM is the additional angular momentum from the melted ice, redistributed as a function of latitudinal angular momentum. dF is differential redistribution caused by continent-ocean constraints. I'm confident that you will find that the additional differential off-axis angular momentum will be miniscule compared to the total. There will of course be some effect upon the Earth's spin axis, but this will be just another of the small catalogue of mass distribution effects which contributes to a somewhat chaotic wobble in the Earth's spin axis, which is typically in the order of a meter or two. When global warming gets worse and huge masses of ice /water are redistributed, then I'm guessing that the effect could be orders of magnitude more - tens or hundreds of metres maybe? Also consider that the Earth behaves like a gyroscope, so much of the additional angular momentum will exhibit as rotation around other axes, much as hurricanes rotate in the atmosphere.


How to make, read, and calibrate a ping-pong ball anemometer?

The drag coefficient varies with Reynolds number and hence with wind speed. Most fluid-dynamics textbooks have a graph of the drag coefficient of a sphere versus Reynolds number. Hopefully that could help. (A sphere such as a ping-pong ball is the best shape since its shape is the same in all orientations --- only a sphere has complete omnidirectional symmetry.) Because wind is rarely steady but usually includes gusts and lulls, it may be necessary to account for overshooting. A sudden gust can cause the ping-pong ball to temporarily overshoot to a higher angle than in a steady wind at the same speed as the gust.


This is a part answer, as pinning down the actual date that the canal formed is not well framed in the literature.

According to the Texas A&M University web-chapter The Vaupes Arch and Casiquiare Canal Barriers and Passages  (Winemiller and Willis, 2011), are quite vague about exactly pinning down the age of the canal, with

  Extensive alluvial sedimentation and channel
  meandering provided subsequent opportunities for drainage
  capture between the Orinoco and Negro headwaters to the
  east of the Vaupes Arch, and at some point the Río Casiquiare
  formed a connection between the upper Orinoco and upper
  Negro rivers

and by using digital maps based on the topography suggest that

  the upper
  Casiquiare course may have been captured quite recently by
  the Pasiba–Siapa–lower Casiquiare drainage network as a result
  of river meandering on the peneplain.

The article The Casiquiare river acts as a corridor between
the Amazonas and Orinoco river basins: biogeographic
analysis of the genus Cichla (Willis et al. 2001) are more direct in stating that

  Unfortunately, the precise timing of the origin of the
  Casiquiare remains unknown

also stating that in studies of the DNA of species in either basin, there seems to be little dispersal between them through the canal.  Specifically noting that the

  Casiquiare River acts as a selective filter, where only
  some species are able to make the transition from
  stained, acidic water in the Negro River to unstained,
  neutral water in the upper Orinoco River.

Winemiller et al. (2008) state in the article Fish assemblages of the Casiquiare River,
a corridor and zoogeographical filter for
dispersal between the Orinoco and
Amazon basins (2009), that

  Hydrologically, the
  Casiquiare represents a stream capture in progress, but there is
  some debate concerning its formation

Secondly, an answer to your question as to why the water does not stay in the Orinoco, it is a question of elevation, according to Winemiller and Willis, (2011), it is a case of flowing downstream from the western edge of the Guiana Shield, the direction governed by the elevations of the two ends of the bifurcation.

  At its origin at the
  bifurcation of the upper Orinoco, the Casiquiare
  is about 90 m wide and lies at an elevation of 120 meters
  above sea level (m-asl). At its mouth at the upper Rio Negro,
  the Casiquiare is over 500 m wide at an elevation
  of about 90 m-asl.

and passes through what Winemiller et al. (2008) describe as an alluvium filled floodplain, that coupled with the meandering and stream capture (mentioned above) has governed the course of the canal.

The Rio Negro being a major tributary of the Amazon River.

Lujan and Armbruster, authors of the chapter The Guiana Shield (2011) assert that

  In the
  future, it is likely that a new drainage divide will form within
  the Orinoco downstream of the Tama-Tama bifurcation, and
  the current headwaters of the Orinoco will become entirely
  adopted by the Amazon


Is there an Existing Model of Computing Rice Sufficiency?

Rice production and yield, like any other agricultural crop depends on a number of factors. These include, but not limited to:

The variety of rice being grown
The fertility of the soil, and this can and does vary between regions
in countries
The availability of water for the variety of rice
Loss due to pests or natural events (ie weather)

When new varieties of rice are developed, test plots are planted in various locations and the yield per area of land, typical tonnes per hectare, are ascertained. Once this has been done for a number of test plots and for a number of growing seasons, average numbers of tonnes per hectare can then be applied to larger/national plantings.

Combine this with data regarding the number of people that need to be fed and the determined average of the amount of rice each person needs it is possible to determine the sufficiency of a rice production.


Why are there no deep caves in the continental US?

It is related with the large-scale geology of the USA and Europe. The USA is rather normal in this regard, but the particular geological history of Europe allowed the formation of exceptionally deep caves there.

During Mesozoic, Europe was a closed ocean: the Tethys Ocean, with shallow carbonated platforms. The Alpine Orogeny formed the continent and the carbonaceous materials emerged creating mountains with large carbonaceous units. The meteorization and erosion of these carbonates created big karstic systems with deep caves.

Conversely, the USA has a lot of Paleozoic units where the carbonaceous materials are too compact to form deep caves. You may have shallow Mesozoic caves near the surface but Mesozoic units are thinner than some folded zones of Europe.


(Why) Is there more landmass on Earth's Northern hemisphere than the Southern Hemisphere?

It would be a strange coincidence (but of course possible) if the landmass would be exactly evenly divided between the northern and southern hemispheres, as defined by the equator. However, you can cut the globe with another plane and form two hemispheres that have the same landmass, eg. any vertical plane that goes through the Geographical centre of Earth.

Calculation of Geographical centre of Earth by whuber at GIS stackexchange

The landmass distribution is largely depending of the location of the continental plates, but Global Paleogeography maps also suggest that the breakup of Pangaea follows other laws than an even distribution between north and south hemisphere.

The problems to find a map that accurately portrays which hemisphere actually has a greater landmass, is probably related to the fact that many popular (and in many ways useful!) map projections are not made to show area relations. Use a globe or equal area projection to compare the size of landmasses.

This might also be an interesting article for you and a starting point for further research: Riguzzi et al. (2009) Can Earth's rotation and tidal despinning drive plate tectonics?. The authors argue that there is a correlation between tectonic movements and rotation of the Earth and the Moon's revolution plane. Tomographic data of slab dip angles support the point and this might also be part of an explanation why earthquakes and volcanism varies along the latitudes and might be rare in the polar regions.


Historically, how has the fraction of Earth covered by water changed?

Can't say much about the later epochs, but the 'hellish Hadean' epoch without oceans is kind of an outdated idea.
We have zircon records indicating that crust and oceanic formation was already done to some unknown extent 4.4 Gyrs ago. The zircon analyzed in the nature paper given originates from interaction with sub-crustal material in a watery environment at this date.


I didn't study tropical soils in any depth, but I've studied quite a bit about wetland soils. In my experience most peaty soils are waterlogged, which would encourage anoxia and prevent decay. Laterites are, from what I've read, usually dry at least part of the year, which would allow bacteria to munch on the organic matter.


The geology of local landscapes and small scale features

(this is consciously the start of the answer - my regional geology books -cf. above comment, are packed away due to a house move).

The rolling hills are very distinctive of the English Jurassic & Cretaceous. Relatively low dipping rocks - long wavelength folds. The ridges are due to rocks that are more resistant to erosion. For example, the English chalk forms the North Downs and South Downs (and the Yorkshire & Lincolnshire Wolds). Chalk is actually more resistant to erosion that some of the surrounding rocks (don't believe me? Have a look at Beachy Head or Flamborough Point!).  These ridges have influenced pre-Roman history - eg. the Ridgeway follows a series of these ridges.

I may be out of date on this, but the folding is usually blamed on the formation of the Alps. The Alps are a long way off, but their influence can be felt as mild folding. The cause must be after the youngest Cretaceous that is present (which I think is the chalk?) - and there was only really the Alps, the Paleogene North Atlantic Volcanism (eg. Skye, Arran, Mull), and opening of the North Atlantic to choose from.

As for your soils: This is where the Regional guide will help. The soils are much more recent. A decent explanation will probably involve at least one ice age, and river courses which have since changed (eg. the proto-Thames used to flow from the North!)


Seismometer records ground displacement or acceleration

A geophone (type of seismometer) contains a coil of wire, wrapped on a mass, surrounded by a magnet. As the Earth moves we assume the mass stays still due to inertia and this changing magnetic field will produce a current in the coil of wire. This current is measured as a voltage and relates to the rate of change of displacement of the Earth with respect to time or:

$$
v \propto \frac{dx}{dt}
$$

Where v is voltage, and $\frac{dx}{dt}$ is the velocity of ground motion. Correct me if I'm wrong but the difference in seismometers eg. MEMS accelerometers (acceleration) vs geophone (velocity) is their frequency response.

https://www.crewes.org/ResearchLinks/GraduateTheses/2008/Hons-MSc-2008.pdf


Prompt gravity signal induced by the 2011 Tohoku-Oki earthquake - could this really be useful for warnings?

If you have a sufficient number of sensors, e.g., land-based or ocean-bottom seismometers, in the vicinity of where strong earthquakes typically happen, then it will take a few seconds for seismic waves to reach them, and a few hundred milliseconds for the electric signal to get to a place where a warning could be triggered.

On the other hand, the gravimeter would provide essentially instant warning. So you save a few seconds. At the same time, it takes many many seconds for earthquake waves to travel to the places where the warning would matter. In fact, the earthquake rupture itself may be many many seconds long. And it will take minutes for tsunamis to reach shore.

In other words, what you gain in advance warning time is not actually very large, and it may not be worth the effort. I would also not be surprised if it takes tens of seconds or minutes to actually see the change in gravity in noisy gravity measurements, and/or to take the same amount of time to just process the data.


When it is said that air moves from warm object to a cold object, how is it possible that air moves from high pressure area to low pressure area?

You are correct that air generally moves along the surface from high pressure towards low pressure (not directly, but deflected due to the coriolis effect).

However, this does not imply that it is moving from a colder area to a warmer area. And, there is nothing contradictory in a cool air mass moving horizontally to displace a warm air mass.

Extratropical cyclones (a kind of low pressure system found in mid latitudes) are actually related to the movement of a cold front and a warm front, as part of a frontal wave. They drive cold and warm air masses to move.

Your claim that "air moves from warm object to a cold object" might be the root of your misunderstanding. That claim isn't true. It is true that heat will move from a warmer object to a cooler object through conduction and radiation. But that is not related to whether the air itself will move. A local effect called a "sea breeze" demonstrates the opposite scenario. A hot beach creates a warm, rising column of air (and a local area of low pressure), bringing in cooler air from the ocean to replace it.

You have conflated the transfer of heat with the movement of air and air masses.


When taking these standardized tests, the first thing to do is to try to solve the problem. If the problem is weirdly stated, as standardized test writers are wont to do, the next thing to do is to eliminate obvious non-answers. (I didn't know that when I took those tests 40+ years ago.)

Choices C and D are obviously wrong. The data shows that regardless of hemisphere shadows point more or less to the west at sunrise, east at sunset. Since the shadows point opposite the Sun, this means the Sun rises in the east, sets in the west. This leaves choices A and B as the only viable options.

Try to match columns (days) from tables one and two based on shadow length against choices A and B. Day 1 in table 1 is an exact match against day 2 in table 2. This column doesn't help with answering the question. The other two columns do help. Day 2 in table 1 is most similar to day 1 in table 2, and day 3 in table 1 is most similar to day 3 in table 2.

Day 2 in table 1 and day 1 in table 2 are most illustrative. Every shadow in day 2, table 1 has some northward component while every shadow in day 1, table 2 has some southward component. Since the shadows point opposite the Sun, this suggests (B) is the correct answer. This is consistent with the other results.

As a sanity check, what about option (A)? This is not consistent with the tabulated results from day 2 in table 1 versus day 1 in table 2, or from day 3 in table 1 versus day 3 in table 2. Option (B) is the only possible answer.


A recent 2016 Stanford University study reported in the article "Oxygen-starved oceans held back life's recovery after the 'Great Dying'", suggests that

  Analysis of ancient seabed rocks from disparate locations reveal that life did not rebound until anoxia had fully ebbed.

Specifically, the researchers found evidence from a lot of places around the world that, according to the researchers, point to a possible conclusion that globally

  anoxic conditions reduced seawater oxygen levels by 100-fold at the onset of the mass extinction. Oxygen levels then slowly rose, only returning to pre-extinction levels after 5 million years, corresponding to when the climate became more stable and life regained its former diversity.

This research paints a picture that the mass extinction event resulted in a global anoxic event, that took the Earth a considerable amount of time to recover from.


Open source seismic refraction processing

There are several references to refraction tools in the Wikipedia page for free geophysics software:

https://en.wikipedia.org/wiki/Comparison_of_free_geophysics_software


The Iberian plate may have been a sub-plate once-upon-a-time, but in modern maps it is usually shown as part of the Eurasian plate, and the next plate to it is the African plate. The same thing applies to the so-called Indian plate. Prior to 43 million years ago it was indeed a separate plate, but then it fused with the Australian plate and there is no longer a plate boundary between India and Australia. The resulting plate is therefore usually referred to as the Indo-Australian plate.

A lot can happen in tens of millions of years, and one of the things that can happen is a change in plate boundaries. There is no longer a plate boundary between what was the Iberian plate and the Eurasian plate. If you are referring to events which happened tens of millions of years ago, it might make sense to refer to them a separate plates, which is why the article you quote refers to an Iberian sub-plate.


Modified blackbody model of earth. What is wrong with it?

The premise that the Stefan-Boltzmann equation is used for greenhouse gases is wrong. The Stefan-Boltzmann equation is used for irradiance output, not energy input. The ground warms the atmosphere, and the atmosphere releases energy into space.

I suggest looking at the one-dimensional energy balance model. See http://kurs.uib.no/acdc/filer/219.BYQINh.pdf


Are the polar vortexes main cause of ozone hole?

To blame ozone destruction on the polar vortex would be like blaming trees for surface ozone production downwind of cities. Yes, nature is involved in the process, but nature is not the source of the catalytic pollutant that caused large change in ozone concentrations.
The polar vortex is a naturally occurring meteorological phenomena that has occurred for millions of years, and the ozone layer was fine.  The issue is man-made halogenated compounds that catalytically destroy ozone (e.g. CFCs) when polar stratospheric clouds (PSCs) form.  The stronger the polar vortex, the colder it is and the longer the PSCs stick around, allowing more destruction of ozone.  The continental ice sheet over the south pole allows extremely cold temperatures, and so PSCs have been more prevalent there. Typically the Antarctic circle is much colder than the Arctic, so ozone destruction has been more prevalent in the southern hemisphere.  However, polar stratospheric clouds are occurring with increasing frequency in the Arctic.
I suppose you could argue that if there were no polar vortices, the ozone layer would not be so susceptible to CFCs.  However, the polar vortex and associated PSCs is a natural phenomena we cannot avoid.


How to Interpret this set of Latitude and Longitude?

It looks like your coordinates are written in decimal degrees but with the decimal points omitted.

34.144442 -118.654084 corresponds to 34°08'40.0"N 118°39'14.7"W.

Google maps shows this to be a location just outside LA.


What causes lava eruptions (and shutoffs)?

Basaltic magma (pictured above) rises for several basic reasons: 1) High temperature, low density liquid mass that is buoyant relative to surrounding rock and 2) Low crustal overburden stresses that allow upward movement of the underlying buoyant magma.

Many magmas fail to break the surface if overburden keeps them "capped", but they can flow horizontally (ie between sedimentary bedding planes) if that's where the zone of weakness lies. Many may also simply lose their heat to surrounding rock and solidify on their upward migration. In many cases, buoyancy of rising magma may meet a layer of similarly dense material, effectively stopping it in its upward track.

Heat loss is important as magmas can stop flowing once relieved reservoir pressures slow upward flow to the point that rising magma cools faster than it can be replenished from below; as the flow trickles down, what's left just cools down, solidifies in place and flow stops.

On the other hand, a large reservoir contains both enormous buoyancy and, importantly, heat. That heat, constantly replenished by a large supply below, will prevent excessive conductive heat loss to surrounding rock and solidification of magma pathways, ensuring the path to the surface stays open. It's also worth noting that the local stress field changes as a magma body is emptied and can also work, along with heat loss, to cap flow.


Differences between hydrothermal vents on Earth and Europa

At the moment, the question is unanswerable, because nobody knows if the vents exist - or even if there is an ocean under Europa's icy exterior (although the idea is reasonably well-accepted). At the moment, they're hypothetical, and until a mission is sent to Europa to observe the depths of its oceans, we won't know much about them.

Well, there actually is one difference. On Earth, hydrothermal vents are the byproducts of tectonic activity. They occur near where tectonic plates meet - for example, in the Mid-Atlantic Ridge, or the Pacific Ring of Fire. On Europa, however, the source of the vents is thought to be tidal interactions with Jupiter, which provide enough heat to keep the ocean from freezing solid, like the moon's exterior.

There is one interesting difference regarding the impacts of vents, described in part of this paper (starting at the bottom of page 7, then jumping in more detail to page 10), which is that Earth's oceans are stratified (i.e composed of distinct layers, stemming from effects of heating, cooling, and convection), whereas Europa's ocean may be unstratified and uniform. On page 10, the authors explain this by saying:

  Earth's ocean is stratified because it is both heated and cooled at different locations along the upper surface. Water cooled at the poles slides beneath warm tropical water, forming stable stratification. If the dominant source of buoyancy in Europa's ocean is heat input at the base, the situation is more reminiscent of a pot of water on a stove, or of convection in the Earth's liquid core. The fluid should be convectively unstable everywhere, and stable stratification should not occur.

The authors say that they can apply this unstratified model to plumes from vents and therefore better explain ocean dynamics on Europa.

Sources:

National Oceanic and Atmospheric Administration

Woods Hole Oceanographic Institution

"Hydrothermal Plume Dynamics on Europa: Implications for Chaos Formation" by Goodman et al.


How big does a pointed piece of tungsten need to be to self-propel into the earths core by gravity alone?

It will never get past the mantle.

The tungsten (or tungsten carbide) will chemically react with the rocks surrounding it to dissolve and form other minerals (silicates), or even worse: get diluted to trace levels in mantle minerals. Compare this with dropping some grains of salt in the ocean and asking when they will arrive to the sea floor. Your block
of tungsten will probably need to be on the scale of tens of metres or more (km?) to escape that.

Furthermore, the mantle is convecting so it will keep your thing from sinking directly down. Compare with leaves falling from a tree in a thunderstorm. This will encourage the chemical mixing I mentioned before.


During an average winter, what part (if any) of the Mississippi River becomes unnavigable?

Upper Mississippi river near St Paul Minnesota is closed December - March.  US Army Corp of Engineers is responsible river navigation in the United States.  From winonapost.com, (from 2015) the article states that all vessels need to be south of Lock and Dam 9, near Lynxville, Wisconsin.  Sounds like the upper river is closed so locks can be dewatered and maintanence performed.

My guess is most of the Mississippi river remains open to navigation south of Wisconsin during the winter.

US Army Corp of Engineers river navigation site.


What would the equilibrium temperature be at the poles in a world without seasonality?

If we consider that by "Assume daily cycle and convection and so on operate as usual" you meant that all heat transport from/to the pole remain as it is today. Then, we can do a back of the envelope calculation. This calculation will at least give you an order-of-magnitude answer, and we can then consider everything that would affect the result.

Currently both poles radiate more energy than they receive trough direct solar irradiation. This is because they are colder than the rest of the planet. Therefore, there is a neat heat transport from the equatorial latitudes to the poles. That heat travels on atmospheric and oceanic currents. This figure nicely summarize this radiation balance:

Figure from here ©The COMET Program

If we consider that the heat transport depicted at the bottom of the figure remains the same. The only change in the energy budget would be from solar irradiation, and once they start warming the only way to release the additional heat and reach equilibrium would be trough infrared radiation (black body radiation).

The poles receive zero energy on the equinox and the winter solstice and 12.64 kWh/m$^2$ per day on the summer solstice. Therefore a rough yearly average would be 3.16 kWh/m$^2$ per day. So, if we were locked on a summer solstice state you would receive four time more energy, and none if locked in a winter solstice state.

Summer solstice locked pole

Let's consider the summer solstice case first. If we call $E_1$ the current amount of outgoing radiation from the pole, and $T_1$ the current temperature. The Stefan–Boltzmann law states that

$E_1 = \sigma T_1^4$

Analogously, if $E_2$ and $T_2$ represent the summer solstice locked state, you have

$E_2 = \sigma T_2^4$

Considering that $E_2 = 4 E_1$

You can write that

$4 = \frac{T_2^4}{T_1^4}$

Or

$T_2 = \left(\frac{1}{4}\right)^4 T_1 = 1.41\, T_1$

Therefore the temperature would increase 41%. It doesn't sounds much, but considering that the temperatures above are in Kelvin, it es a lot! In fact, with the current mean temperature in the north pole of -16 °C (257K), it would go up to +89°C!! And the South pole would go from the current -49°C (224K) to +42°C.

This diverges from any posible reality because with 89°C at the north pole there would not be a net influx of energy from the equatorial latitudes as we are assuming. Instead, atmospheric and oceanic currents would take a lot of that heat down south and the temperature would equilibrarte at a much lower value.

Note that in the above calculation I've ignored the energy flux due to advection in atmospheric/oceanic currents. I did so because that flux is about five time smaller than the flux from solar radiation, so it won't change much the results and ignoring it simplifies the math. You can do the calculation considering those flows if you want.

Winter solstice locked pole

In the case of a pole locked to a winter solstice. There would be no incoming solar radiation at all. Therefore, all incoming energy would be transported by currents from equatorial latitudes. In that way, we can see in the above figure that the north pole receives about 150 W/m$^2$, and the south pole about 100 W/m$^2$. The equilibrium temperature would be reached when they radiate the same amount. So, using Stefan–Boltzmann law again we can do some rough calculations.
Let's call the south pole temperature $T_{SP}$ and $T_{NP}$ for the north pole. Then:

$T_{SP} = \left(\frac{E_{SP}}{\sigma}\right)^{1/4} = \left(\frac{100 \,W/m^2}{5.67\times 10^{-8}}\right)^{1/4} = 205 K= -68°C$

And for the north pole

$T_{NP} = \left(\frac{E_{NP}}{\sigma}\right)^{1/4} = \left(\frac{150 \,W/m^2}{5.67\times 10^{-8}}\right)^{1/4} = 227 K= -46°C$

But again, with such cold temperatures the actual inflow of energy would be grater and the equilibrium temperature would not be that extreme.
In any case, that condition would be favourable to the growth of a massive ice sheet in the corresponding polar area, in the same way I describe in this question and answer.

As a final thought. For this condition to happen in real life you would need something analogous to Tidal locking to lock the period of Earth's precession (currently about 26,000 years) to exactly one year. And don't know of any mechanism that could achieve that.


It is "mean sea level above the Baltic Sea", in meters (source on page 109).

That explains why it is used mainly in East-European countries.

Martin Ekman - The Changing Level of the Baltic Sea during 300 Years - A clue to understanding the Earth shortly mentions some historical 'zero points' (page 111).

As mentioned in the comments:
mBf means méter Balti felett (Hungarian for meters above Baltic Sea). They also use meters above the Adriatic as a datum (https://en.wikipedia.org/wiki/Metres_above_the_Adriatic, mAf from méter Adria felett).


P and S waves are fundamentally different, when it comes to properties of the wave. An example might be that P waves can travel through fluids while S waves cannot. However, when it comes down to wave theory, these two are just different polarizations of a mechanical wave.

Seismology

In seismics this concept may be puzzling as we make some very fundamental assumptions. However, seismologists are very well aware that these polarizations (they call them phases) usually change throughout their travelpath. When you look at the image below, you can see different travelpaths and the same source will trigger P and S waves. This P wave will travel to the point P where it can be recorded as direct P wave. Upon reflection it will be partially converted to a S wave, which you can also see on the nomination PP is the P part of the reflected P wave and PS is the S part of the reflected and converted P wave. (Actually you can go on happily converting back and forth.)

Seismics

In seismics we get this conversion on interfaces or layer boundaries (whichever name you use). So everytime a wave is reflected it may also be partially converted into a different polarization. So essentially, your statement is wrong. The wave doesn't just convert passing through a layer, it is converted upon interaction with an interface.
So while this wasn't a yes directly to your question let me elaborate why this conversion happens.

This picture basically shows the rate of conversion depending on the incident angle. At 30° the rate of conversion is maximized. (The scales are terrible to read sorry.) At this interface we can see the incident wave as excitor of a new wave package. So we have to take a detour into wave excitation.

Exctiting waves

In marine seismics we can excite pure P waves, because we're operating in a fluid. On land you will always excite a mix of P and S waves (and variations thereupon, namely surface waves). The excitation of these waves is direction dependent. Starting a P wave in one direction will always start an S wave component perpendicular to this direction. Of course we have some energy distribution so that we get something like this:

P waves in the + direction and S waves in the - direction. (This image was vor conductivity but it serves the point.)

At the interface

We have to look at the incident wave as an excitor at the interface, which will give us a P and a S wave response. In seismics, wave theory and other solutions you can usually see the S wave solution stands perpendicular on a P wave solution (except when we're dealing with anisotropy). So yes in the end your incident wave will start two P waves and two S waves that look like this:


Looking for global cloud cover animations or videos

That kind of "moving clouds animation" is a very common one, as it is used routinely to aid in weather forecasting. However, it is not very common to see it in a whole-world geographic projection as the example you show, I'll elaborate later on why that's the case.

Traditionally, a common source of "cloud animations", have been NOAA's geostationary GOES satellites, in operation since 1975, with 17 satellites launched so far and more to come.

If you are looking for visually compelling animations, the latest GOES-16 satellite is capable of producing color images of the Earth's disk every 15 minutes at a resolution of 0.5 km per pixels (at the equator). They look like this:

And you can access images and animations pretty much right after acquisition, here is an example of the 24 hours before I posted this (reduced to a 20% of the size due to Stack Exchange upload size limits):

You can see updated animations at any time on the GOES-East Image viewer.
More traditional, B&W images (infrared band) can be found in the NOAA GOES page, or many other weather data sources. Also, beside GOES satellites there are many other geostationary weather satellites that cover different parts of the globe.

The reason images like the one you posted are rare (whole-Earth images), is because these kind of images are either taken from:

Geostationary orbits, that can't see polar areas and suffer of a strong degradation of the ground resolution per pixel at higher latitudes, or
Polar sun-synchronous orbits, like MODIS or Suomi, that allow whole-world composites but using images from multiple passes. Therefore, the full image is composed of images acquired at different times, leading to an ambiguity in the image's time and an impossibility to produce a seamless image, due to the de displacements of the clouds between the different passes.

Worldview is a great source of such multi-temporal composites, and as an example, here is a preview of yesterday's cloud cover by Suomi:

Worldview also allows to produce animations of the cloud cover spanning several months at one day interval. You just have to click on the video icon in the lower left and select the dates interval.

The GOES-East Image viewer stores images of the last four days (with some gaps some times), if you bulk-download them you can create longer animations. As an example, I just did a one of the last four days that you can see here (I do recommend to enable HD resolution).

Another interesting one, that also allow for animated display is the EPIC camera on DSCOVR satellite. Despite that the time resolution is a bit too low for looking at the clouds evolution, its unique perspective from the L1 point (42 times further than geostationary orbits) allow a full view of the illuminated side of the Earth. In addition from the animation in the link above, this video is also worth checking.

You can also find animations created using models instead of real data. That approach allows seamless global coverage at an arbitrarily high temporal resolution. A nice example is the one year long animation (at one hour time steps) of cloud cover and precipitation created from the NCAR's CESM model.


viable geothermal energy supply from exhausted fracked gas wells?

Viability of an oil or gas well for geothermal energy production is dependent upon several factors:
 - Geothermal heat profile with depth near the well
 - Depth of the exhausted well
 - Volume of fluid acting as a heat exchange around and near the well.

I think it might be possible to use exhausted natural-gas wells will be suitable for re-use as a geothermal energy supply. Likelihood of success would require site investigation and the engineering pilot study.  This idea would be ideal for university engineering / geology research.


Why do tropical cyclones around Australia have erratic paths?

The paths of cyclones in the Australian Basin are no more erratic than cyclones, hurricanes or typhoons elsewhere. Conditions at the time of a cyclone's existence determine its path.

Sinuosity of Cyclone Tracks - SW Indian Ocean states that over the past three decades the sinuosity of cyclone paths in the SW Indian Ocean has a high degree of variability. It appears that in that part of the world, cyclones can make more abrupt changes in their paths during January than in other months of the cyclone season. It also goes on the state there are marked periods when the paths of cyclones are less sinuous and other periods when they are more sinuous when compared with long term averages.

The following picture, from Wikipedia, shows the paths of the cyclone tracks for the 1988-89 south west Indian Ocean cyclone season. A number of the paths are erratic.

Paths of other cyclones can be seen on the following Wikipedia pages:

1988-89 SW Indian Ocean Cyclone Season

1988-89 Australian Cyclone Season

2013-2014 SW Indian Ocean Cyclone Season

1985-1990 Southern Hemisphere Cyclone Paths

Paths of the World Hurricanes, Cyclones & Typhoons for the past 170 Years

NOAA Site displaying the paths of past cyclones, hurricanes & typhoons

Tracking paths for current cyclones in the Indian Ocean & Western Pacific


Could the earth be much older than the currently accepted number?

The age of the solar system is 4.6 billion years.  We know that because almost all meteorites are 4.6 billion years old¹.  Therefore, that puts a very solid upper boundary to the age of the Earth.

According to solar system models, it took between 10 million and 100 million years for the Earth to form in the early Solar System.  That result is consistent with the independently estimated age of the Earth of 4.54 billion years old.  The Earth could maybe be 10 million years older, but it certainly couldn't be older than the solar system.

None are older.  We've never found a meteorite from outside the solar system.  I expect some scientists would have given an arm and a leg for the opportunity to sample some rocks from interstellar Oumuamua but it was not possible.