Online resources for geographical distribution of minerals

You did not mention why you are interested in brannerite, so I am assuming you want it as a collector's specimen and not a microscopic crystal.

Unfortunately, there is no definite source. However, there are some possibilities:

Try the Handbook of Mineralogy: http://handbookofmineralogy.org and more specifically the brannerite page. You will fine there a more detailed list of localities for that mineral.
Another option is to run a Google Scholar search for brannerite. You can find scholarly papers dealing with brannerite, and occasionally they also mention where they found the mineral or how they obtained it. Notice that in the specific case of brannerite, there are many articles dealing with brannerite structure. This may not be what you're looking for. There is also the problem of accessibility - unless you have an institutional or personal subscription to these journals, you may not be able to access the full article. However, sometimes this information can be found in the freely available abstract.
Go to Rocks & Minerals magazine and run a search there for brannerite. They may have some articles dealing with localities.

Regarding your second question about geological features, the features may be mapped if they are big enough. This is probably true for granitic gneisses, may be true for pegmatites and conglomerates and unlikely for veins and placers. This will not help you though. Even though the mineral appears in let's say gneisses, 99.9% of gneisses will not contain this mineral. Of those 0.1% that do contain it, only a fraction will have it big enough so you will be able to see with without a microscope, or any larger than a speck of sand.

Finding rare minerals is indeed hard. If however you do indeed come across brannerite, I would like to remind you that it contains quite a lot of radioactive elements so don't make jewelry or good luck charms out of it, and washing your hands after dealing with it is usually a good idea.

Good luck!


does silt form from sand ; does clay form from silt

Sand to silt is a physical process, silt to clay is most often a chemical process.

Sand and larger rocks are physically weathered to form silt, everything from frost wedging to simple abrasion.

Clay is a different creature entirely, for a start there is a disagreement about the definition of clay across disciplines. Several disciplines of geology use different size based definitions.  Clays can for from physical or chemical processes depending on the type of clay. Most often clay form from the hydrolysis of tiny mineral particles.


How to graph gravity as a function of depth, given radius and density?

As long as we deal with a spherically symmetric planet, the mass of the shell above you does not influence the observed gravity; the little mass close by exactly cancels the large amounts of mass far away (you would float inside a planet if it looked like a pingpong ball and had all its mass centered on the surface!), this is called Newton's Shell Theorem.

You can then compute $g$, acting as if the mass $M$ is concentrated at a point on the centre of the sphere. Thus, combining your knowledge of the mass $M$ underneath you, and the radius $r$ towards the center of this planet, you can compute the gravity field using the equation you give!

For a constant density we have a volume $V=\frac{4}{3}\pi r^3$, thus mass $M=\rho_1 V$, and the gravity is given as $g(r)=\frac{GM}{r^2}=G\frac{4}{3}\pi r \rho_1$, linear like you found. For two layers, it is a sum of this first mass $M_1=\frac{4}{3}\pi_1R_1^3$ and second mass $M_2=\frac{4}{3}\pi_2(r-R_1)^3$ but ONLY when this mass is below you, i.e.
$$g^*(r) = \begin{cases}G\frac{4}{3}\pi \rho_1 r & r\leq R_1 \\ G\frac{4}{3}\pi( \rho_1\frac{R_1^3}{r^2}+\rho_2\frac{(r-R_1)^3}{r^2}) & r>R_1\end{cases}.$$
This should not be linear anymore due to the $R_1^3/r^2$ contribution!

Good luck!


Are plastics a carbon sink and how much carbon is released to the atmosphere making them?

The idea of a carbon sink is a bit misunderstood here. The idea of a carbon sink is a reduction of carbon that comes from the atmosphere. It must “fix” carbon that is already in the air. Trees are a carbon sink, for the most part, because their mass is made of of carbon obtained from
The atmosphere. Unless the plastic formation process you are thinking of is vastly different that any industrialized ones, they are taking carbon from oil essentially. Since the carbon from the oil
Has not yet been released into the atmosphere, it would not qualify as a sink.


What are the farthest Time Zone locations?

The original wording of your question revealed that you are missing something about what time zones are, and how they are defined. So let me start from the begin. If you are impatient, you can jump forward for the answer in bold font after the figure, and come back here for the explanation.

Time zones are defined by by man just to facilitate time keeping. In principle the idea is that time anywhere should be such that noon happens when the Sun reaches its maximum elevation over the horizon.

Time keeping wasn't easy in the past. Therefore, time was kept by astronomical observatories. And due to the extent of the British Empire, in history was the observatory at Greenwich the one that stayed as the global reference point for time and longitude (because at first the main utility of precise time was to compute precise longitudes).

As Earth's rotates 360° in 24 hours, that's 15° per hours. So if you know the longitude of a place, you just divide that longitude by 15 and you know how many hours you have to add/subtract from Greenwich reference time to get your local time. For example: If you are in Eastern Island at longitude 109°W, it means your local time will be the time at Greenwich (know as Universal Time or UT) minus 7 hours 16 minutes ($109/15=7.26\, h = 7h\, 16m$), if you use that time, the Sun will effectively be at its highest point at 12:00 h.

But as you can see, if you move in the east-west direction, every point would have a different time if we just use the above rule, which is very inconvenient, as the time in the east side of a city would be different than the time on the west side.
For this reason they invented Time Zones: to keep the same time within reasonable large areas. In principle they created time zones every 15°, so that no point would be more than 30 minutes off their solar time. In other words, the moment the Sun reaches its maximum elevation in the sky won't be more than 30 minutes off from clock's noon.

However, this time zone lines crossed political borders, so they were adapted and bent so that whole countries or at lest states remained within a single time zone. That way the current designation of time zones was established and is neatly summarized in this figure from Wikipedia commons.

You can see that the most extreme time zones are +14 hours at Line Islands (Kiribati), and -12 hours in and around Baker Islands (US).

Therefore, the maximum possible difference between times on Earth is 26 hours. That means that at 11:00 PM of a Monday in Baker Island, it is 1:00 AM of a Wednesday in Line Islands.

As both places are fairly close to the equator, I doubt they use daylight saving. Therefore, that would be the maximum. In the case of Apia in Samoa, it also uses +14 hours but only in summer.

If you are mostly concern to the time difference with the UK, the largest would be +14 hours to Line Islands.

Finally, take into account that time zones are politically defined, so at any time a political decisión can change the actual answer to this question.


What are the causes of lower UV radiation at lower elevations?

You are almost totally correct when you asked:

  What are the reasons for that? Is it simply because there are more air molecules that absorb the radiation?

The Ozone Layer blocks most of UVB, but does not affect the amount UVA entering the atmosphere (as seen in the illustration below):

(Image source)

But there is a little more to it than that. From NASA's Earth Observatory's webpage What Determines How Much Ultraviolet Radiation Reaches the Earth’s Surface?, elevation's role in attenuating UVB (and by similar processes, UVA):

  high elevations UV-B radiation travels through less atmosphere before it reaches the ground, and so it has fewer chances of encountering radiation-absorbing aerosols or chemical substances (such as ozone and sulfur dioxide) than it does at lower elevations.

The aerosols absorb and scatter incident UV radiation.  So nearer to the surface, there is a greater concentration that the light must pass through - and as the altitude decreases, the UV radiation path is therefore increased, so the further 'down' in altitude, the more the air mass and an increased presence of aerosols absorb and scatter solar UV radiation.

In respect to the aerosols in area you have specified (the Dead Sea), according to the first link in your question, The Analysis of the Ultraviolet Radiation in the Dead Sea Basin, Israel (Kudish et al. 1997), they state

  the air above the Dead Sea is characterized by a
  relatively high aerosol content due to the very high salt content of the Dead Sea

Their results indicate that

  The relative attenuation in the ultraviolet range as a function of wavelength, i.e.
  site-specific spectral selectivity, decreases with increasing wavelength.

thus, indicating that the attenuation is also wavelength dependent.


I would agree with your hypothesis, but I must point out that it will likely break down further and further as you approach the tropopause. Whether the ISA model is actually a average, I cannot say. However, the idea that the ISA model is a horizontal average is plausible.


Strange circular structures found on a photo from Mars rover Curiosity at Dingo Gap

There are no circles, it is an image artifact. Here is another picture from Dingo Gap that shows nothing at the exact same position.

Your mind is a well-trained pattern-matching machine that makes up patterns even when they are not actually there.
In other words don't jump to conclusions. You are claiming that there are actual structures, which is one step too 'far'.

(Credit: Emily Lakdawallah blog post)


Does "wind" include the air molecules involved, or merely the kinetic energy?

Kinetic energy is the work needed to accelerate a mass. Wind defined as the velocity air (not the same as energy, as noted in comment).

However, the air moved by wind is a good example of kinetic energy, molecules are accelerated by a difference in pressure and moved. When the pressure difference decreases, the movement of molecules stop. So yes, the wind moves matter with weight.

However, weights of gases are somehow difficult to sense, as any gas would replace the weight of the air that normally surrounds us. The weight of the air can therefore be understood as the pressure generated by the weight of all the air above. Air particles moves from high pressure to low pressure and so the wind is formed.

A way to show how efficiently the wind is actually moving the air masses, is to consider how the wind can transport solid matter, sailing boats, wind mills and even sand and rocks. For example the Harmattan, a wind from the North that transport huge amounts of dust from Sahara to the coast of West Africa and the Atlantic Ocean. Other air borne sediments can form thick formations of Loess or other aeoloian formations as sand dunes. Also consider how the wind can move clouds and how all water in rivers and lakes therefore have been transported by the wind.

I hope that this, very simplified answer will make you more interested in meteorology and Earth science in general.


Pretty confident to answer No here.

Tsunamis are caused by water displacement due to earthquakes; this has nothing to do with global warming.  Any changes in density would be trivial, and although the water would have more thermal energy, this would not affect or be influenced by the kinetic energy of the Tsunami.

The only way in which a tsunami would be made more severe would be that any sea level rise due to global warming would be added to the Tsunami height.


What is the CI chondrite concentration of REEs/rare metals, in ppm/grams per ton?

You should start with the GERM Reservoir Database. Not the easiest to use website, but the most comprehensive. You can look up elemental concentrations in all kinds of "reservoirs", including meteorites. For example, look up CI Chondrites to see the elemental values that are commonly used for REE-diagram normalisation. You can look up by specific meteorites, or averages of groups. You can see values by paper, and in most cases they also include a scan of the original data from the paper itself. Note that it's also usually good practice to actually read the paper to understand how the data were collected, analysed and what do they mean.

That said, as for your general idea of using asteroids as ore deposits for rare metals:

  ...because I want to investigate the notion that asteroids represent abundant stocks of rare resources.

As a rule of thumb, this works well for the PGE (platinum group elements) and related metals (Te, Au, Re). The reason is that those metals are chalcophile or siderophile, and in the Earth they are concentrated in the core and depleted in the mantle and crust. In (some) asteroids, this differentiation did not occur and the concentration of these elements is still (relatively) high in the bulk material.

However, the REE and other HFSE metals (i.e. Zr, Hf, Nb, Ta), are not concentrated in the core. In fact, being lithophile elements, they are particularly enriched in the Earth's crust. Going to mine them from asteroids will be pointless.

Here are some more questions and answers that will clarify some concepts:

Why is uranium only in the crust, really?

What is the difference between chalcophile and siderophile elements?

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


Is there a recent global gridded temperature dataset with 0.1 deg resolution?

The most important reanalysis datasets covering until present time (I'm excluding the others that stop some years before present time) currently available are:

ERA5 by ECWMF: 1979-present (soon 1950-present), temporal resolution of 1 hour and spatial resolution quarter degree (0.25 x 0.25);
CRU by the UEA: 1900-present (some variables 1850-present), temporal resolution 3 or 6h, spatial resolution half degree (0.5 x 0.5);
GLDAS by NASA: 1948-present, temporal resolution 3 or 6h, spatial resolution quarter degree (0.25 x 0.25).
ERA5-LAND by ECMWF: 1981-present, temporal resolution of 1 hour and spatial resolution 0.1°x0.1°, global coverage, but only land-covered surface.

(please, feel free to edit the answer to add more)
You could download one of those and process these temperature data using a simple resampling procedure bringing it at the resolution you are interested in by using CDO or another similar software. The procedure could be based on a bilinear interpolation of the original data with a finer grid. This would bring uncertainty because the correct procedure would be to use the reanalysis as boundary conditions in a regional climate model, but it would give a good approximation of the data you are looking for.
The only dataset I am aware of that is providing global data at a resolution of a 0.1 deg. resolution is the MSWEP by JRC and Princeton, but present data are not available for free, and it includes only precipitation data.


This equation is a form of the Shallow-water equations, which are derived from Navier-Stokes in the incompressible limit and the vertical direction is integrated out.

One then takes the equation for the vorticity (which has only one component then) from the Shallow-water equations. The vorticity is split into planetary vorticity, as is the Coriolis term with the $\beta$-sheet-approximation.

Additionally it looks like they're using a velocity streamfunction.


What is the percentage of the global water cycle (evaporation, precipitation) that occurs over the ocean?

The bulk of the planet's precipitation falls from convective storms that develop throughout the Intertropical Convergence Zone (ITCZ). The ITCZ transits north and south of the equator due tracking the sun's zenith throughout the year and is skewed by the position of land, but is generally situated near the equator over the ocean.

Trenberth et al (2006) go into detail describing the different components of the global hydrological cycle, but the core of their research can be summed up in the image below.

~96.5% of the world's water is held in the oceans.
~90% of evaporated ocean water leads to precipitation over the oceans.
~77% of precipitation falls over the ocean.
~10% of evaporated ocean water leads to precipitation over land. This equals the roughly ~10% of runoff that returns to the oceans.
Envirotranspiration from plants plays a noticeable role in the water cycle over land.

Personally, I do wonder about the ~77% falling over the ocean.  That number seems a slight bit low given recent remote sensing data of global annual precipitation.


As the number of ocean dead zones increases, is the world's primary source of atmospheric oxygen (phytoplankton) at risk?

Yes, it is, though probably not immediately. Ocean and atmosphere deoxygenation is a thing, and many publications are out.
In a larger context, deoxygenation is indeed inevitable even if we ignore anthropogenic warming. Increasing solar flux alone (the sun get's hotter over its lifespan) could reduce the atmospheric oxygen to 1% of present day level within around a billion years, says this publication.
This publication estimates that almost 80% of ocean deoxygenation under current day CO2 levels have not been realized yet, but they say that oceanic surface deoxygenation will stop once CO2 emissions stop, while the deep ocean oxygen levels will continue to decrease.
A global warming by 6°C (which is at the upper end of current projections until the end of this century) could tip the oxygen production by phytoplankton, cancelling the ocean's role as a main oxygen producer.
Citing from the abstract:

[...] If, in the course of time, the oxygen production rate becomes too low or too high, the system’s dynamics changes abruptly, resulting in the oxygen depletion and plankton extinction. Our results indicate that the depletion of atmospheric oxygen on global scale (which, if happens, obviously can kill most of life on Earth) is another possible catastrophic consequence of the global warming [...]


What are the non-anthropogenic causes of The Netherlands' low elevation?

Forming of coastline

During the last ice age, the North Sea was dry. When the ice melted sea levels slowly started to rise again and due to tides and currents
a barrier of dunes was formed along what approximately is today's coast line. This created an area of land that fell dry during ebb-tide and flooded during high tide (this can still be seen in the 'Waddenzee' in the North of the Netherlands where you can walk to some of the islands during low tide). The big rivers that flow through the Netherlands brought in more sand, slowly keeping larger parts of the land dry.

Isostatic rebound

During the ice age, the surface of Scandinavia was pushed down. After the ice melted it started to rise again and pushed the Western and Northern part of Netherlands down. Strangely enough the Southern and Eastern parts of the Netherlands are rising, so it seems the Netherlands is tilting.
I'm not sure how large the isostatic effect has been, but we know that the North of the Netherlands is still going down with about 2cm per century (source in Dutch).

Human influence

I know you've asked for non-anthropogenic causes, but I'm going to include this anyway because it seems human influence has had a much bigger effect on elevation than the isostatic rebound.

In the 11th century the Dutch started to actively shape the land by building dikes and later also by using wind mills to pump out water. The Flevopolder is an example of a large part of land that has been created by the Dutch in the 1950s and 60s. When groundwater levels became lower the moors settled and started oxidizing. Researchers think that the settling and oxidation of moors today is responsible for up to 15mm decline per year (source in Dutch).

Additionally in the 16th and 17th century a lot of peat was removed from the moors and used as fuel. Peat removal created new lakes, but some of those lakes were pumped dry later and were used as farmland. Also, the weight of dikes and houses on moors still cause subsidence today in areas in the West.

In the Northeastern part of the Netherlands gas extraction has also caused local elevation drops of up to 30cm (source in Dutch) in the last 40 years.

Other sources (all in Dutch):

http://www.geologievannederland.nl/landschap/landschapsvormen/strandwal (forming of shoreline)
http://nl.wikipedia.org/wiki/Veenpolder_(poldertype) (Dutch moors)


Alternatives to Plant Functional Types as parametrisations in land surface models?

The approach used by Alton et al 2011 is appropriate for the scope and intent of this paper - to demonstrate a weakness in the approach - but is not a comprehensive analysis of PFTs in models.

I think it is useful to question the use of PFTs but incorrect to conclude that Alton et al claim PFTs are not useful. Alton et al show that albedo, net shortwave radiation, and runoff are insensitive to PFT-specific values of four parameters, but they also find that net carbon balance is sensitive.

The study's conclusions are limited to the JULES model that is evaluated and the parameters that are allowed to vary (and thus be estimated by inversion). There are many different models of terrestrial ecosystem functioning, and many approaches to model parameterization. Furthermore, JULES has more than 50 parameters for each PFT, and only four were varied in this study. (This is the number of parameters set in JULES' fortran namelist under JULES_NVEGPARM and JULES_PFTPARM).

This study also provides examples of how inversion using what are essentially 'free' parameters (analogous to 'flat priors' in a Bayesian context) has limitations. Fig 3 shows this, since the 'retrieved' (inverse-estimated) parameters are inconsistent with direct measurements of these parameters. This is more of a limitation of the inversion approach for estimating PFT-level parameters than of the utility of PFTs as an approximation of plant physiological diversity.

To answer your question - yes, there are alternative approaches to both model structure and parameterization. This is an active area of research (and one I am interested in). Here are some examples, in order of increasing complexity (and data and computational requirements).

Global land surface models like JULES are necessarily more abstract (and use PFTs to represent a 'Biome').
Represent groups of individuals that belong to a particular PFT and age class (This was first done in the Ecosystem Demography model (Moorecroft et al 2001, which has both evolved to ED2 and has been integrated into NCAR's Community Land Model.
Vary parameters dynamically in both space and time. For example, Wang et al 2012 show that varying Vcmax in (vertical) space and time improve estimates of gross primary productivity in a very simple crop model.
Individual Based Models (IBM's) represent individuals explicitly. These are reviewed by DeAngelis and Mooij 2005.
Using probability distributions to reflect parameter variability in the system being studied. I am not aware that this has been attempted.

However, adding more degrees of freedom limits inference - too many unconstrained parameters make it difficult to parameterize the model, understand its output, or make general conclusions about how the world operates.

Remember "All models are wrong, but some are useful" - George Box

Wang et al 2012 Impact of nitrogen allocation on growth and
photosynthesis of Miscanthus (Miscanthus x giganteus). Global Change Biology - Bioenergy. doi:10.1111/j.1757-1707.2012.01167.x
P. R. Moorcroft, G. C. Hurtt, and S. W. Pacala 2001. A Method for Scaling Vegetation Dynamics: the Ecosystem Demography (ED) Model. Ecological Monographs 71:557–586. doi:10.1890/0012-9615(2001)071[0557:AMFSVD]2.0.CO;2
DeAngelis and Mooij. 2005. Individual-Based Modeling of Ecological and Evolutionary Processes. Annual Review of Ecology, Evolution, and Systematics. doi:10.1 146/annurev.ecolsys.36.1020


Does the Sun and Moon basically appear to "move on the sky" identically regardless of location and date?

Like Fred said, this probably belongs on Astronomy SE, but I'll give my best answer anyways.
No, the sun and moon do not take the same path each day. The key to understanding this is knowing that the earth is tilted 23.5$^\circ$.

Let's take an example- the arctic circle. On the summer solstice, the sun doesn't set- It goes around and around (called the midnight sun). In the winter solstice, the sun doesn't rise in the Arctic circle.
I think a careful observation of mine might be useful for you. The word Mediterranean means "middle earth." Tolkien is likely referring to the specific geography- specifically the area around the Mediterranean Sea. In fact, Tolkien does state that the Mediterranean is the place he envisioned, but he does use a flat earth, so the cosmology doesn't really match up with reality. This is also another nail in the coffin for flat earthers.


Where can I find solar radiation data for specific land areas?

The Measurement and Instrumentation Data Center (MIDC, http://www.nrel.gov/midc/) provides Irradiance and other Meteorological Data from several stations. Have you also check in: https://mapsbeta.nrel.gov/nsrdb-data-viewer/? Some of the data maybe until the end of 2012 used to be in http://rredc.nrel.gov/solar/old_data/nsrdb/. Good luck!


How does the precession of the Earth's apses affect climate?

During the 20th century, the global mean temperature in January was 12°C while it was 15.8°C in July. This is a bit paradoxical as insolation is currently about 7% higher during January than it is in July. So why is July warmer than January?

The solution to this apparent paradox and the answer your question (how does apsidal precession alone affect the climate) are one and the same: The uneven distribution of land and water between the northern and southern hemispheres. The northern hemisphere has about twice as much land as does the southern hemisphere. Continental climates exhibit much more seasonal variability than do maritime climates.

That worldwide insolation is greatest in January and least in July is a bit irrelevant. What is more relevant is the length of the seasons in the northern hemisphere. Right now, summer is longer than is winter in the northern hemisphere because perihelion is in early January. This situation will be reversed in ten thousand years when perihelion and northern hemisphere summer solstice coincide. Looking at precession only, glaciation is much more likely during periods where northern hemisphere summers are short and winters are long.


Why are $\small\sf{CH_4}$ and $\small\sf{CO_2}$ levels coupled during the Pleistocene?

This question is addressed in a Nature paper on "Understanding the glacial methane cycle" (Hopcroft et al. 2017).

There conclusion is that changes in methane concentrations are driven by changes in the biosphere associated with the global temperature changes. The dominant factor is the reduction in methane emissions from wetlands in a colder climate. There is also a reduction in emissions associated with forest fires in the cold phases (colder climate means less forest fires; warmer climate means more forest fires).

Note that the model used by Hopcroft et al. has the CO2 levels prescribed. In this situation the temperature changes in response to the CO2, and then the methane changes in response to the temperature.


Why is Arizona the fastest-warming state in the U.S. (since 1970)?

The University of Arizona's South West Climate Network webpage Precipitation Changes  (Lenart, 2008) provides a detailed account of the causes of the warming in Arizona and the south-west region of the United States.  Principally, a major factor to consider is that the region is already arid, with low precipitation and high temperatures to begin with.

According to Lenart, global climate models predict that precipitation in the region is expected to drop in the region by between 5-10% by the end of the century.  Less rainfall, coupled with higher temperatures would cause an increase in dryness, hence droughts and sudden downpours.

The mechanism behind this precipitation drop is described by Lenart as being due to an increase in the area under the Hadley Cell circulation, resulting in a movement of the jet stream further north - resulting in winter storms bypassing the southwest altogether.  Some of the models predict there would be a northward shift of the subtropical anticyclone.

So how do these models match the observations?

Observations and measurements have found that

  lower precipitation rates in the Southwest correlated with positive phases of the atmospheric pattern known as the Northern Annular Mode (NAM), which they attributed to an associated northward shift of the jet stream during these years. Meanwhile, the Rocky Mountains, headwaters of the Colorado and Rio Grande rivers, tended to register higher precipitation rates during these positive phases, consistent with the observation that the jet stream was shifting north.

However, extreme precipitation events, such as the record breaking September, 2014 floods in Phoenix, as the remains of Hurricane Norbert swept through, are increasingly likely.  Crucially, from Lenart:

  Precipitation records contain a high degree of variability, however, as they are influenced by a variety of other factors in addition to climate change. For instance, much of the upward trend in the precipitation record from 1950 probably stemmed from an abundance of El Niño events in the second half of the record, according to Martin Hoerling, the researcher who conducted the analysis.

An interesting and somewhat ironic twist implied in the document The Heat Is On: U.S. Temperature Trends is a speculative point that

  points out that since cleanair
  regulations have dramatically reduced these
  emissions over the past 20-30 years, the cooling
  e"ect has already disappeared and will no longer
  be a factor in the future. If the study’s findings turn
  out to be applicable to the warming hole, then it
  is possible that without aerosols screening solar
  radiation these regions will catch up.

Anthropogenic sources, including land use can, according to the article Mesoscale Disturbance and Ecological Response to Decadal Climatic Variability in the
American Southwest (Swetnam and Betancourt, 1997), can amplify, mute or be utterly confounded by anthropogenic effects.


The rocks are undoubtedly of volcanic origin, and I would attribute the marks on their surfaces to shrinkage while their interiors were still in a semi-molten condition but rapidly cooling. The white crystals are probably quartz.


By Hydrostatical Law, $p_a = \rho gh$, at a given $h$. However density varies with altitude and with temperature. Temperature varies by altitude. $g$ constant varies with altitude.

That expression is for water, which has more or less constant density, and it is for depth rather than height.
Ynou need to change this to a differential equation. This is fairly easy: $$\frac{dP(h)}{dh} = -\rho g\tag{1}$$
This assumes the atmosphere is in hydrostatic equilibrium: Every layer of the atmosphere bears the weight of all of the mass above the layer.
Another key equation is the ideal gas law, $PV=nRT$. This can be rewritten in terms of local density as $$P = \rho R_s T\tag{2}$$ where $R_s$ is the specific gas constant, the ideal gas constant divided by the mean molecular mass of the gas. Combining equations (1) and (2) yields $$\frac{dP}{dh} = -\frac{g}{R_s T} P\tag{3}$$
Assuming that all of the factors $g$, $R_s$, and $T$ are constant results in an exponential: $$P(h) = P_0 \exp\left(-\frac{g}{R_s T}h\right) = P_0 \exp\left(-\frac{h}{H}\right)\tag{4}$$
where $P_0$ is the pressure at the surface and $H$ is the scale factor height, $H=R_s T / g$.
The exponential atmosphere model assumes constant temperature. This is not a valid assumption. Temperature drops with increasing altitude in the troposphere, rises with increasing altitude in the stratosphere, and drops again with increasing altitude in the mesosphere. Above the mesosphere, the assumptions of a specific gas constant and constant gravitational acceleration also fail.
The assumptions of a specific gas constant and constant gravitational acceleration are approximately valid in the troposphere. An approximate model for temperature in the troposphere is to assume a constant lapse rate $L$: $$T(h) = T_0 - L h\tag{5}$$
where $T_0$ is the temperature at the surface and $L$ is the lapse rate, the rate at which temperature decreases with altitude. Combining equations (3) and (5) results in a solvable first order differential equation, with solution $$P = P_0 \left(1-\frac{L}{T_0}h\right)^{\frac{g}{R_s L}}\tag{6}$$
This still assumes constant gravity and and constant atmospheric composition, and it assumes hydrostatic equilibrium (equation 1) and an ideal gas (equation 2). None of these are even approximately true above the mesosphere.
Increasing accuracy means that atmosphere models become ever more empirical. The models are still tied to physics, but they are also tied to observations. Lower atmosphere weather models have to eliminate the assumptions that pressure, temperature, and atmospheric makeup are functions of elevation only. Upper atmosphere models have to account for variations in solar radiation. One solar flare can make the upper atmosphere expand by over an order of magnitude.


Would a Yellowstone eruption destroy global agriculture?

An eruption of the Yellowstone super volcano would cause agricultural disaster over a very large area. Its global effect would be significant, but not totally devastating.

The resulting climate cooling could last up to a decade. The temporary climate shift could alter rainfall patterns, and, along with severe frosts, cause widespread crop losses and famine.
But a Yellowstone megablast would not wipe out life on Earth. There were no extinctions after its last three enormous eruptions, nor have other supereruptions triggered extinctions in the last few million years.

Eruption of super volcanoes is rare which makes it difficult to ascertain what exactly would happen when the Yellowstone super volcano eventually erupts - which won't be any time soon.
Yellowstone last erupted 174 000 years ago, which was a minor eruption. Lava from Yellowstone won't be the problem, but the ash and gases will be.
The last major eruption, 630 000 years ago, covered much of western and central United States with ash. The maximum thickness of the ash from that eruption is 660 ft. The eruption was a double eruption, 170 years apart. The amount of ash thrown into the atmosphere with each eruption caused the ocean to cool by 3 degrees Celsius with each eruption.


Let's start with the simplest fact.  With nothing else going on, air in our atmosphere will always be cooled at 5.4°F/1000ft (or the more widely used 9.8°C/km), due to it expanding in size (often times we'll throw a negative sign: -5.4°F/1000ft... this is just to emphasize that these lapse rates are about the air COOLING).  Every bit of the rising air cools at that rate (the oxygen, the nitrogen, even any water vapor in the air).  All of it will cool at 5.4°F/1000ft.  All rising air always expands at this same rate.

However sometimes there is a second complicating factor: the rising air may cool to the point where it is holding its maximum quantity of water vapor (because when colder, air cannot hold as much water vapor).

When it reaches this point, it is saturated, and any more cooling/rising will force some of its water vapor to condense instead into liquid droplets.  For this gaseous water vapor to become a liquid, its particles must expel quite a lot of energy.  And that energy gets released into the air.

So once air hits this saturation point, though its expansion continues to have a -5.4°F/1000ft impact on the temperature, it also has a second factor, that released phase change energy, warming the air some.  The result is that saturated air doesn't cool as fast.

Whenever air isn't saturated, it cools at the 5.4°F/1000ft (9.8°C/km).  We call this the dry adiabatic lapse rate because nothing else is altering the process.  We aren't assuming 0% moisture.  It doesn't matter, as long as it's not 100% moisture.  Water vapor cools just like every other molecule unless saturated.  The first 6 pages of these notes go into intimate detail for why the value is 9.8°C/km, but basically it depends only on the values for gravity and the specific heat capacity of water, plus any error in the hydrostatic approximation... all of which are minuscule for large air masses in the troposphere.  For all intents and purposes, the dry (unsaturated) adiabatic lapse rate on Earth depends on nothing, it is always 5.4°F/1000ft (9.8°C/km)
Then when air is saturated, because the condensation process hinders the cooldown by adding its energy, we call it the moist adiabatic lapse rate to distinguish it.  Picture moist as having an image of water DROPS, which you only get when saturated, due to condensation.  Moist and dry both have some water vapor.  But only moist has water droplets.  The moist adiabatic lapse rate has a smaller value because it is cooling LESS overall (due to the warming impact from the latent heat release).  But it is still cooling, just less.  The moist adiabatic lapse rate varies depending on how much water is actually released (which is based upon the amount of water held, or consequently, the temperature).  If you really wish to dig into the fine details, this AMS link gives the formula.  But generally the moist adiabatic lapse rate is around 5-7°C/km, or 2.5-4.0°F/1000ft, in the low-levels of the atmosphere.


Newton's estimate of the age of the Earth

The estimates of Newton and Kepler, and the similar estimates of dozens of their contemporaries, were produced by treating the Bible as a historically accurate document and deriving a chronology from it. I think that a detailed explanation of their techniques would be off-topic for Earth Science, but the Wikipedia page on the Ussher Chronology (which provides probably the most famous biblically-based estimate of the Earth's age) goes into reasonable detail about the methods used for such calculations.


What is the amplitude of the largest internal wave ever observed?

I believe the largest internal waves ever recorded in the ocean were observed in the South China Sea (SCS). The diagram above is from Alford et. al (2010) - see the two ridges near A1 and N2? The gap between them is just the perfect size so that the barotropic tide can interact resonantly and give rise to very long internal tides which radiate away towards MP2 and eventually shoal (they also go the other direction but we ignore that since it's more or less the open ocean).

The internal tide is very long, but its amplitude is not that large. However, as the internal tide shoals it fissions into a train of solitary waves. The leading solitons in the wave train are larger in amplitude but smaller wavelength than the original internal tide that gave rise to them. Each soliton propagates at its own speed with the largest amplitude wave propagating faster. As the amplitude of each individual soliton grows, the fluid velocity will eventually exceed the wave speed and the waves will break due to convective instability (overturning). Thereby depositing their energy nearshore, far away from the generation zone.

The largest amplitude wave measured in this study was around $200$~m, measured at LR2. But I am pretty sure I have seen other studies with larger amplitude waves in the SCS.


What caused peak CO2 to rise, starting about 400,000 years ago?

First things first: There's nothing per se wrong in science with answering "We don't know" to a vexing problem. This might well be one of those cases.

The question you are asking was asked by Imbrie and Imbrie in 1980. The problem you have noticed (a very strong interglacial despite low Milankovitch forcing) is now known as the "stage 11 problem", and this appears to be closely associated with the transition from a ~41000 year glacial cycle to the ~100000 year cycle we have seen for the last 900000 years.

Why "stage 11"? This is a reference to the concept of Marine Isotope Stages, depicted below. The Marine Isotope Stages refer to the abundance of oxygen 18 relative to oxygen 16. Water made of two protons (hydrogen) and one oxygen 16 atom evaporate more readily than does the slightly heavier water centered on an oxygen 18 atom. This makes the oxygen 18 levels in oceanic deposits a very nice proxy for climate.

Source: https://skepticalscience.com/print.php?n=1703

Three key transitions can be seen in the above graph. The glacial cycle started to change from a ~41000 year period to a ~100000 year period a bit less than one million years ago. The second transition occurred after MIS 17 when glacials shifted to being more extreme. The third transition, the one that you noticed, occurred after MIS 12 when interglacials shifted to being more extreme. This latter shift is the core of the "stage 11 problem".

The key issue with explaining the observed ~100000 year cycle is that the Milankovitch forcings for a 100000 cycle are rather low while the Milankovitch forcings for a ~41000 year cycle are very strong. The stage 11 problem gets at the very heart of the 100000 problem because stages 12 and 11, which mark an extremely large swing in climate, occurred when Milankovitch forcings were very low. One non-solution of this stage 11 problem is that the onset of stage 11 (or possibly the onset of the preceding stage 12) represents when the 100000 year cycle finally took full control. This is essentially the argument made by Berger and Wefer.

So, rhetorically, what did cause this shift from a glacial cycle of ~41000 years to ~100000 years, and why did it take half a million years for this transition to become complete? A partial explanation by Abe-Ouchi et al. is that something happened between 0.4 and 1.0 million years ago that enabled hysteresis loops. Instead of disappearing on a 41000 cycle, ice instead built up to such thick levels that all of the ice didn't melt at what would have ended a 41000 year glaciation. Once that happened, it wasn't much of a jump to survive two 41000 year cycles. But by then the ice had become so very thick that all that was needed was a mild forcing from warming to make the ice melt catastrophically.

This still falls in the "and then magic happens" category. One very plausible hypothesis that has gainied a lot of traction (e.g., Bintanja and Van de Wal) is that those massive ice sheets eventually pushed the built-up regolith from the 200+ million years since the previous ice age (the Karoo) either out to sea in the north or in huge piles of glacial drift to the south.

The initial glaciation events of the current ice age that started about 2.6 million years ago were rather weak in part because regolith makes for a rather nice ice lubricant. Those comparatively weak glaciation events continued for the next 1.6 million years, at a 41000 year interval. Much of the regolith had been pushed out of the way by a million years ago. While regolith is slippery (to ice), bare rock is anything but. This stickiness enabled ice to build up to the extent that those hysteresis loops could start to form, sporadically. It took another half a million years for the transition from a purely Milankovitch-driven 41000 year cycle to a Milankovitch+hysteresis 100000 year cycle.

References:

Imbrie, John, and John Z. Imbrie. "Modeling the climatic response to orbital variations." Science 207, no. 4434 (1980): 943-953.

Berger, W. H., and G. Wefer. "On the dynamics of the ice ages: stage-11 paradox, mid-Brunhes climate shift, and 100-ky cycle." GEOPHYSICAL MONOGRAPH-AMERICAN GEOPHYSICAL UNION 137 (2003): 41-60.

Abe-Ouchi, Ayako, Fuyuki Saito, Kenji Kawamura, Maureen E. Raymo, Jun’ichi Okuno, Kunio Takahashi, and Heinz Blatter. "Insolation-driven 100,000-year glacial cycles and hysteresis of ice-sheet volume." Nature 500, no. 7461 (2013): 190.

Bintanja, R., and R. S. W. Van de Wal. "North American ice-sheet dynamics and the onset of 100,000-year glacial cycles." Nature 454, no. 7206 (2008): 869.


What caused this waterfall to have rounded formations?

Looks like alkali earths ( Ca, Ba , etc.) carbonates deposited from a supersaturated hot spring. As the water emerges from the spring, carbon dioxide leaves the water and the water cools, it precipitates the carbonate ; you could call it limestone. There may be other minerals that will precipitate from a spring. From the foliage , it looks like a relatively recent development.


How to set up a domain from namelist in WRF?

There is a WRF domain Wizard offered by ESRL. You can download it here. Also, don't make the same mistake I made using Lambert Conformal- keep stand_lon the same as your ref_lon.


Why is a future increase in solar luminosity by 10% supposed to have disastrous consequences for life on earth when the last 30% did not?

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

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

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

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

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

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

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


If it's really hard, I'd tend toward an iron base mineral of some kind. Gold is not very hard. Just hedging bets, you should always bet iron because its so common.

It also doesn't look like any gold ore I've ever seen, but I've only ever seen pictures. I understand that gold ore usually has free and unattached veins (looks like lovely yellow gold stuck in a rock), while the small remaining minority is wrapped up in pyrite or something else by as much as 1 oz gold to 1 ton rock (not very profitable outside of industrial mining). Unless there's literal tons of it, I'd just carry on with your business.

I'm not sure what lab testing would cost or even how available such services are, but if you can find something cheap enough and they also promise anonymity (you want privacy if you're sitting on a literal gold mine), might be worth quelling the curiosity.

A quick google search found this site: How to Test for Gold Ore - Sciencing. The page promises to be an accurate, at-home testing method for identifying gold ore. You would need some acids (I guess you can just buy those) and gold testing wires (which might be expensive).


At what point does plate tectonics stop?

One permanent threat to plate tectonics is the oceans vanishing. The scientific jury may still be out on this matter, but most geologists and geophysicists consider water to be the lubricant that makes plate tectonics possible. In a billion years or so, the Sun will have become 10% more luminous. This is conjectured to make the Earth to undergo an unstoppable moist greenhouse / runaway greenhouse, and the oceans will vanish.

The core is still emitting residual heat from the formation of the Earth. As the core cools, iron in the outer core freezes onto the inner core. This is freezing is an additional source of heat. The solidification of the Earth's core thus represents another permanent threat to plate tectonics. The liquid outer core is conjectured to have frozen solid less than three billion years from now.

A nearer term threat is the formation of the next supercontinent. Plate tectonics may operate in fits and starts. What makes subduction zones form is not known. What is known is that a major subduction zone vanished when India collided with Asia, and no new subduction zones formed elsewhere to take its place. If this conjecture is true, plate tectonics will temporarily stop in a few hundred million years when the next supercontinent forms, only to restart later when too much heat stress builds up inside the planet.

This is all highly conjectural. No scientist will live to see their conjectures falsified.

References:

Kasting (1988), "Runaway and moist greenhouse atmospheres and the evolution of Earth and Venus," Icarus 74.3 : 472-494

McDonough (2003), "Compositional model for the Earth's core." In Treatise on geochemistry 2 547-568.

Silver & Behn (2008), "Intermittent plate tectonics?" Science 319.5859.


How is dense magma able to rise and punch through continental crust?

Your intuition is quite correct: Other factors being equall, a dense magma will not rise through lighter rocks. The exception is if it is under pressure, in which case a fluid magma will escape through 'pressure release' pathways, either laterally or vertically (or in complex geologic structures, in a variety of irregular pathways). Magmas may begin to crystallize at depth. As they do so, the volatile components, such as water, carbon dioxide, halogen acids, and sulphur dioxide, become relatively enriched in the residual magma, where they can build up enormous gas pressures. The most spectacular results are in Plinian-type volcanoes, and in many less dramatic eruptions. Consider, for example, pumaceous lava, which is essentially gas bubbles frozen-in during the process of escape. At depth there are no such bubbles. but the gasses are still there, and still exerting a huge pressure.

Otherwise, a magma may simply rise because of thermal expansion reducing the density to less than that of the host rock. Most likely the magma will rise as a combination of both mechanisms.

Also, you mention the Great East Africa Rift, which is notable for some extraordinary carbonatite lavas and related carbonatite-silicate hybrids, which are less dense than almost all of the other African crustal rocks.


Flexure of a viscous lithosphere - derivation

The problem with my derivation is I am not sure if it correct and I do not have a way to check it.

Try dimensional analysis to check your solution. Is your solution consistent with dimensional analysis? Estimate a solution to a real example, based upon you knowledge of geophysics and geology. Does your solution even come close to a reasonable estimate? If you are unfamiliar with dimensional analysis and estimation methods, I recommend the online book (MIT course) Street Fighting Mathematics for some possible ways to stimulate ideas of ways to check your derivation.

For example, as you have written your solution, the $b$ and the $\alpha$ are constant over time ($t$) and location ($x)$. First substitute your solution into the differential equation, and carry out the differentiation to confirm that it is in fact a solution. If it can be verified as a solution, turn your attention to the dimensions of b and alpha. The dimension of b must be time and the dimension of alpha must be length. You are modeling the system as a viscoelastic solid, so the the initial condition ($t=0$) for your displacements $w(0,x)$ are just the elastic solution, and the time-dependent term is unity. Use the elastic solution to solve for alpha (the characteristic wavelength) because this does not change over time. Name the purely elastic displacement '$e$' and it has dimension of length.

You know you want to include viscosity somewhere, so let's try the kinematic viscosity $v$ (dimensions $M*M/s$). So try $b = -(L * L)/v$, or $b = -(L * 1)/v$, because this is a 2D problem and can be one unit deep. You'll need the negative sign to make the displacement grow faster for a smaller viscosity.

What could $L$ be? I would try $L=e$, or $L=e/2$. Because you really don't know the kinematic viscosity of the lithosphere, the factor is not critical.

Substitute $b$ and $\alpha$ into your solution. Does the result seem to make physical and geological sense?


How much energy is required to hold the earth’s atmosphere up against the forces of gravity?

I can not comment on whether your understanding about the formation of the atmosphere (your first paragraph) is correct. However, given that the complete atmosphere lied at the surface at some point, it is possible to calculate the amount of energy to lift this towards its current state.

The calculations will be done for a small surface area of one meter squared and choosing values corresponding roughly to the global averages.

First we calculate the gravitational potential energy of the atmospheric column as follows

$$ E_{atmos} = m_{atmos} \cdot g \cdot h_{atmos}$$

with $h_{atmos}$ the height of the center of mass of the atmospheric column. Surface atmospheric pressure ($P_{surface}$) is the force resulting from the mass of the atmospheric column under gravitational acceleration. Therefore, the above can be rewritten as

$$ E_{atmos} = P_{surface} \cdot h_{atmos}$$

The centre of mass at the atmosphere is approximately at $h_{atmos}$ = 5 km (one can look at maps of the 500 hPa geopotential heights for example). For surface pressure we can take the standard atmosphere (101325 Pa). Plugging in the numbers:

$$ E_{atmos} = 101325\,Pa \cdot 5000\,m = 5.1e8\,N m^{-1} = 5.1e8\,J\,m{-2}$$

To get to the total energy, this number needs to be multiplied by the surface area of the earth. However, it is more insightful to get a certain timescale out of this value. We can calculate how long it would take for the sun to deliver this energy to the earth's surface.

$$ \tau_{sun} = \frac{E_{atmos}}{SI_{avg}}$$

With $SI_{avg}$ the global average incoming solar radiation (not taking into account atmospheric absorption). Plugging in the values

$$ \tau_{sun} = \frac{5.1e8\,J\,m{-2}}{340\,W\,m{-2}} = 1.5e6 s = 17.5 days$$

So it would take about 17-18 days for the sun in order to 'lift up' the atmosphere from the surface to its current height.


What is the most powerful natural catastrophic event on record?

hard to impossible to tell. In recorded history it was for sure one of those massive volcanic eruptions from Krakatoa, Yellowstone or Tambora. But in earth's history there were some impacts from meteorites or commets that must have been a lot more powerfull in terms of released energy than any volcanic erruption. My guess is the Vredefort crater in South Africa (largest verified impact crater on Earth with a diameter of 300 km) or the Chicxulub crater in Mexico that is said to have triggered the mass extinction of the dinosaurs.


If radioactive decay supplies only about half the Earth’s heat, what are the remaining sources of heat?

Mostly it is residual heat energy from when the Earth was very young. The biggest source came from the kinetic energy of all the bodies, big and small, that collided to form the Earth being converted to heat. The differentiation of the Earth added even more heat energy to the Earth.

In addition to radioactive decay, the on-going freezing of the outer core material onto to the inner core adds a bit more heat to the system, but neither one compensates for heat transported through the mantle and crust and then out into space. Note that this heating from below is but a tiny portion of the overall energy budget for the Earth's surface.

Even the Earth's surface was very hot shortly after the formation and differentiation of the Earth. While the surface cooled quickly (geologically speaking), the interior has not. The key reason is that 2,890 km of rock makes for a fairly thick blanket.


Potassum-Argon Dating and Proportions of Daughter Products in Potassium 40 Decay Channel

Potassium 40 has a half life of 1,300,000,000 years,  which means that within that time half of the 11 percent which you refer to will have decayed to form Argon 40. Potassium 40 has two modes of decay, which is unusual for a radioactive isotope. Only 11 percent of it becomes argon 40, the remaining 89 percent decays by a different mode and becomes Calcium 40. but there is no need for you to worry about Calcium 40, it is the 11 percent of K40 which becomes Argon 40 which is useful in dating ancient rocks. Fortunately geologists don't have to wait until it has completed one full half life for it to be useful. By assessing the amount of Argon which has accumulated within the material since it was ejected by volcanoes in pristine condition and had no Argon at all in it, geologists can get a rough idea of the age of the rocks. The potassium/argon method is very tricky to carry out and error can easily creep in.


Does Start / Stop technology in cars have an impact on air quality?

Generally idling will cause pollution in specific isolated areas and start stop technology could irradicate that pollution.  Here I will concentrate not on the global impact of the pollutants but at the location where the pollution is released.  The differing scenarios are important to how much of an effect start-stop / idling will have on air quality.  The location affected by idling will of course determine what air quality affects.  Taxi ranks, junctions, high streets, spaces outside schools, hospitals and other areas where cars often stop for longer than a few seconds.  The longer you idle and the more cars there are, the more pollution you would create in that specific location.  The number and type of person in the location where the idling is taking place would make a difference to how the air quality would affect people.

I present a few scenarios (a link at the bottom for my calculations)

A long journey with minimal stopping
Here the savings on pollution would be negligible because the car would not be stopped idling for much time at all!  Although of course the locations where the car does stop would be subject to fewer pollutants.

Major junction at 11:30am on a weekday (figures taken from Preston Circus Brighton)
During a full cycle of all traffic lights going from red to green and back for all junctions, 69 cars passed during 112 seconds.  The cars used an estimated 0.451L of petrol.  During this time 32 cars waited for 30 seconds using 0.2L of petrol.  Idling in this scenario is responsible for 44% of the fuel used and therefore I assume idling is responsible for 44% of the pollution.  It is a place where pedestrians will wait at crossings, drivers will sit in their cars, cyclists will stop catching their breath and where pedestrians sometimes have alternative routes.
44% here is a huge and very significant number.

Single car waiting in a single spot
In a car you would use around 0.75L of petrol per hour idling and you would change that single location from being pollution free to a place equal to a single lane road with regular traffic (1 car every 12 seconds)

A 1.5km stretch of road with 4 major junctions with traffic lights
A single 1.5km stretch of road could have four major junctions in a busy city.  A car stops twice for a combined total of 2 minutes.  The car will use around 0.025L of petrol idling.  Driving along this stretch of road would use around 0.15L of petrol, assuming the amount of fuel is equal to the pollution then start stop could reduce pollution by 6%.  This is a fairly small amount compared to the total but it is still significant difference in the air quality along a large stretch of road.  Streets like these in city centres will have many more people than in other areas waiting at the lights, walking along pavements, people working in shops, people living in flats above the roads, cyclists and drivers will be in their cars taking in the pollution.  These areas are some of the most dangerous generally for people because of the number of people so 6% could make a significant difference.

A taxi rank
A taxi rank with 10 cars idling in a space of around 35m. That 35m spot could have the air quality equal to a reasonably busy dual carriage way (a car every 1.68 seconds).  Some taxi ranks are covered (such as those near train stations) which could make those spaces much much worse as the pollution would not be dispersed easily. There will be people waiting for taxis next to the taxi rank, people waiting nearby as taxi ranks are usually in busy locations and the taxi drivers themselves will be sitting directly in these toxic fumes so there will be many people exposed to this pollution.  With start-stop, this pollution would be completely eradicated.

A school
The cars could be spread out more so you could say it would be a half of the above, so a busy single lane A road maybe.  The affects of pollution are greater on children because their lungs are smaller, more sensitive and growing.  Children and babies in prams are also more affected because they are shorter and closer to the pollution.

https://docs.google.com/document/d/1rASB96LRIP1II4vkxGKncshfZpR3iNAy9ONmSHAkTGs/edit?usp=sharing


What is the age of the Gamburtsev Mountains?

The Lamont-Doherty Earth Observatory describes the Gamburtsev Subglacial Mountains (GSM) as being like:

  opening the door of an Egyptian pyramid and finding an astronaut inside.  There is no good reason for an astronaut to be inside an Egyptian pyramid just as there is no good reason for a major mountain range in the middle of East Antarctica.

Despite being buried under a considerable amount of ice and observed to have had slow erosion rates since at least the Permian (Cox et al. 2010), accessible detrital material has been determined to have been deposited as fluvio-deltaic deposits in Prydz Bay (Cox et al. 2010; Flierdt et al. 2008).

$\ce{U-Pb}$ dating of dertital zircons and $\ce{^40Ar/^39Ar}%edit$ dating of detrital hornblendes age them as ~530 Ma and ~519 Ma respectively, with no evidence of any yonger volcanic contributions (Flierdt et al. 2008).  These dates led Cox et al. (2010) to postulate that the GSM formed during the Pan-African Orogeny.

Veevers and Saeed (2013) suggest that detrital zircons found in the Ellsworth Land–Antarctic Peninsula–Weddell Sea–Dronning Maud Land sector of ages 1.4-1.7 Ga, 1.9-2.1 Ga and 3-3.35 Ga possibly have their provenance from the GSM.

In summary, in the absence of direct measurements of GSM petrology, detrital material from pre-glacial erosion has suggested that the youngest tectonothermal evidence is for a Cambrian age of the GSM.

References

Cox et al. 2010 Extremely low long-term erosion rates around the Gamburtsev
Mountains in interior East Antarctica, Geophysical Research Letters

Flierdt et al. 2008 Evidence against a young volcanic origin of the Gamburtsev Subglacial Mountains, Antarctica Geophysical Research Letters

Veevers and Saeed, 2013 Age and composition of Antarctic sub-glacial bedrock reflected by detrital zircons, erratics, and recycled microfossils in the Ellsworth Land–Antarctic Peninsula–Weddell Sea–Dronning Maud Land sector (240°E–0°–015°E) Gondwana Research


How does the amount of mass in an atmosphere affect the seasonal changes and dynamics of the planet's climate?

Seasons are determined by the degree of tilt of the planet's axis, not the mass of the atmosphere.  Mars has an axial tilt slightly larger than Earth, so Mars' seasons are slightly more pronounced than Earth's.  For a planet like Venus, which has virtually no rotation and an extreme axial tilt, "seasons" are also affected by the rotation/revolution ratio.

If you are interested in the climate differences between separate planets, mass of the atmosphere does affect overall global temperature (e.g. more atmospheric mass = more heat trapping) but the mass itself is not the main driver of the dynamic changes of climate within an individual atmosphere.  Really Mars and Venus don't have as much "short term" climate dynamics like Earth, because they don't have ocean/land dynamics.  Though, they definitely have seasons. Earth's "short term" climate dynamics are driven by the heterogeneous distribution of land, ocean, and (to a smaller extent) clouds.

All the planets do share similar long term drivers of climate dynamics, which on Earth are collectively known as the Malenkovitch cycles.  The Malenkovich cycles are on the order of 10s of thousands of years and include changes in axial tilt, axial precession, and orbital eccentricity.  Some would also argue that long term gravitational changes in orbit parameters due to trojan asteroids and large planets like Jupiter also affect the Malenkovitch cycles.  These cycles shift the timing, intensity, and spatial distribution of solar input to the planet.


How to identify low or high pressure area

Because you specifically asked about winds and pressure, there is a fairly applicable rule of thumb.  It's called Buys Ballot's Law.  Basically, if the wind is to your back (coming behind you), and you're in the Northern Hemisphere, generally low pressure is to your left and high pressure is to your right.  This graphic from http://www.maiamarinelli.com/ illustrates it:

However, do note that Buys Ballot is really an imperfect estimation.  There's three big caveats/adjustments to consider:
[in all following description, replace left with right (and vice versa) for Southern Hemisphere]

The Buys Ballot Relationship fundamentally relies upon the Earth's rotation, i.e. the always vaunted apparent force termed the Coriolis Effect.  Coriolis actually causes wind NOT to flow towards low pressure, but instead along equal pressure contours.  If it weren't for the Coriolis Effect, low pressure centers would quickly fill in with air, and we wouldn't have the complex weather that we have.  That said, at the equator, where the differences in rotation with latitude are smallest, Buys Ballot no longer works as there's limited/no Coriolis.  So the nearer the equator you are, the more low pressure would be more infront left, or even straight in front of you if wind is to your back.
Friction also slightly imbalances the relationship near the ground, such that wind actually flows towards low pressure again.  So once again, wind to your back may actually indicate the low pressure center is more to your front left than your left at ground level.  If you were up off the ground, or out in a body of water, this friction adjustment would be minimized, and low pressure is indeed more to your left.
Local effects, such as terrain (or buildings) definitely overwhelm the larger pattern at times.  And because the Coriolis force isn't significant in smaller, more localized features, Buys Ballot's becomes shakier in those situations.  The impetus from the broader wind flow does feed down to guide even pressure local features.  So wind to your back may well be telling you that a smaller area of low pressure is somewhere between to your left and in front of you... but that low pressure could be local: a building... a thunderstorm... even a tornado.  That said, as the pressure gradient gets greater, Coriolis is more and more marginalized, and the low pressure can be almost directly in front of you... and there are even rare circumstances where it is strong that the low can rotate backwards, and low pressure may be to your right.  As far as I know, this scenario only can maintain itself at all in strong thunderstorms, with the quite rare antimesocyclones and anticyclonic tornadoes.  However, perhaps it could also happen on the microscale, such as around buildings, but those circumstances are no within my area of knowledge.

So all that put together:
If indeed you can get away from those big buildings, are fairly removed from the regional impacts of mountains and smaller nearby terrain features, and ideally can escape areas with dense foliage... then if the wind is coming from behind you, you can be almost certain that large low pressure is to your left or front left (in the NH, right/front right in the SH)... if you can find the wind direction.

And if there isn't much wind?  Well then you're probably fairly near a high pressure center!  But that will make it fairly tough to diagnose exactly where high pressure centers/low pressure centers are in relationship to you.

(And if there is a great deal of wind... well maybe you should just get inside, and turn on your tv to find out when the big tornado/hurricane/winter storm is going to end!)

Other options:

You could also use a barometer to diagnose falling/rising pressure trends.  Those indicate that a low/high is moving towards you.  However, this doesn't tell you what direction the low or high is located [though you can often make an educated guess based upon predominant wind flow; most pressure systems come from the west in the mid-latitudes, which include much of the US/Europe/Asia].
As gansub noted in the comments, you could watch how atmospheric conditions evolve, such as the cloud patterns/types.  https://www.youtube.com/watch?v=tsD6zkBMmck is a reasonable description of what goes on around fronts, which could help alert you to incoming storms (both warm and cold fronts are dips of low pressure, and indicate a large low pressure system is coming).  The continuing lack of cloudcover might be an indication of high pressure in the vicinity.


How to characterize flow of nonreactive tracer in a porous media?

Governing Equation
The constitute equation for a nonreactive tracer test is governed by fluid flow due to advection (viscous flow) and fluid flow due to diffusion. The partial differential equation that governs this process is given as:
$$\frac{\partial C}{\partial t} + \nabla.\left(v  C - D\nabla{C} \right)=0$$
Where, $C$ is concentration of the tracer in space $(x,y,z)$ and time $t$; $v$ is the velocity of the injected tracer fluid, and $D$ is the dispersion coefficient.
1-Dimensional Example
Let's consider a following 1-dimensional core in which tracer is injected at left hand side face (point B) as a heavyside unit step function. The output tracer concentration profile is observed at right hand side face (point A):

The boundary conditions for this general scenario are given as follow:
$$\overline C_B=0, x>0, t=0$$
$$\overline C_B=1, x=0, t>=0$$
$$\overline C_B=0, x\rightarrow\infty, t>=0$$
Now, there exists an analytical solution for this 1-dimensional example that can give you tracer concentration at any place within the column, say $x$, at any time, say $t$. That is, we can estimate $C(x,t)$ using the following analytical solution:
$$\overline C_B=\frac{1}{2}\left[1-{erf}\left(\frac{x-vt}{2\sqrt{Dt}}\right)\right]$$
where, $v$ is the fluid velocity which is known and $D$ is the fluid dispersion coefficient which is unknown.
How to Estimate Dispersion Coefficient
One of the data that we obtain from tracer experiment is the tracer concentration with time at the column output (point A), which is also referred to as effluent concentration. Let's call this data as $C_{measured}$.
Similarly, using the above analytical function, we would estimate the tracer effluent concentration (at $x=L$) by guessing some value of dispersion coefficient $D$. However, since this $D$ is just a guess, so the estimated effluent concentration using the formula is not correct. The correct effluent concentration is the one we have measured i.e .$C_{measured}$. You would have guessed by now that we use the measured concentration in the analytical expression to estimate $D$, and the appropriate way of doing this is by devising an objective function and minimizing its square as follow:
$$f_{obj}=min\left[\sum (C_{measured}-C_{calculated})^2\right]$$
So you find $C_{calculated}$ using multiple guesses of $D$ and stop the iteration for that particular $D$ which gives you minimum $f_{obj}$


Where does all the earth from surface mining go?

In opencast mining it is dumped on a huge spoil heap, and if the company is environmentally conscientious or wants to avoid penalties, it is used to fill in the hole left when the mining is finished. With underground mining it is also dumped on spoil heaps, and as it is not practical to infill the mine workings, in best practice the spoil heaps are later landscaped, or at least restored to nature so they are no longer unsightly and could become a nature reserve. Some mining companies are reckless with their waste and dump it into lakes and rivers, potentially causing pollution incidents, though not all mining waste is hazardous.


The simple answer is 'crustal thickness'. The two crustal plates of India and Eurasia are very different in character. The Indian plate is thin, the Eurasian plate is much thicker and more rigid. Both plates are so buoyant with respect to the underlying mantle that neither can subduct in the normal sense. But India is moving so fast that something has to give. The Indian plate is buckling a bit, but mostly being under=plated at low angle as the Eurasian plate rides over it - as it did is such spectacular fashion during last year's Nepalese earthquake.

PS the main continent-continent crunch occurred some 40 to 20 million years ago.


Winter in the Northern Hemisphere in July? Can anyone explain it?

Can anyone explain more didatically how such a shift is expected to
  happen? How the wobble movement is doing it?

First, it's probably a bad approach to think of it as a shift.  It's a rotation.  similar to a spinning top.   It's called precession.  It's always been there - (so to speak).  It's part of Earth's motion.

The Earth is sufficiently massive and space, sufficiently empty that there's effectively zero resistance and the Earth's precession is permanent and largely consistent.  (unlike a top that slows down due to friction from the ground and air resistance).

Earth's precession shifts a tiny bit due to the sun, moon and gravity from other planets but those adjustments are very slow and not relevant to your question.

As Earth's precession completes one rotation every 22,000 years (give or take), over a human lifetime that's about 1.5 degrees or 1.5 days, which is pretty small and easily missed by anyone not taking very careful measurements. That doesn't affect calendars however.

Calendars are a little complicated, and I'm not sure it's necessary to go into that in detail for your question.   Calendars also can be adjusted to match Earth's orbit.   Any un-adjusted calendar will eventually mess things up like putting July in winter, but that has nothing to do with the 22,000 year precession.   365.25 days (a leap year every 4 years), was inaccurate enough to lead to the year that lost 11 days in the UK in 1752.

365.25 days (Julian calendar) is much more accurate than 365 days (which loses a day every 4 years (in effect, a 365 day year would put July in winter in 720 years, not 11,000).  Any movement of winter across the calendar depends on how good the calendar is, NOT earth's precession.

365.242 days (Gregorian calendar), or 97 leap years every 400 years is better than the Julian (1 every 4).  Having an accurate accounting of leap years and being able to add or remove one as needed, will keep winter in the winter months for as long as we need to, much longer than 11,000 years.

What changes with Earths precession is the position of the stars.  The sky will shift depending on where Earth is in it's 22,000 year wobble.  Similarly, the North star won't always be the North star.   The night sky will look shifted by about 46 degrees in 11,000 years (some of the stars will have moved over that time-frame as well, but lets ignore that for now).

You've herd the term "Age of Aquarius".   The astrological ages each last about 1,800-2,000 years, and the cycle of 12 ages corresponds to Earth's 22,000 year wobble.  Note, that article says 25,860 years and your quoted 22,000 years.  The solar system also wobbles, so how those wobbles add up can give different estimates.   If you use 22,000 or 25,860 or 25,771 or 26,000 or 23,000 on average, the different numbers don't change the answer to this question.   This explains the variation in the numbers used.

  Is such an astronomic phenomenon accepted by scientists
  unquestionably?

Absolutely, 100%, unquestionably yes.  This is accepted, measured, confirmed and can be modeled and explained.  It's 100% accepted science.  Even the ancients were able to observe this with careful measurement, though they couldn't accurately explain it.

  If winter is expected to be in July 11,000 years from now and such a
  shift is under way right now, does it mean that winter in the NH is
  slowly moving towards July and that, perhaps, 5,000 years from now
  winter solstice will be in March

As the assumption is flawed, then both no and yes.  With an imperfect calendar, then this would happen and the rate would depend on the accuracy of the calendar as noted above (not precession).

Because we use a very accurate calendar that allows for adding and removing a leap year as needed, no "drifting" of the solstices across the months will happen.   There will be some yearly variation as the solstice is a precise point in Earth's orbit, so it happens not only on a day but at a precise time, it might be December 21 one year and December 22 the next year, but every year our calendar gets "messed up" by about 6 hours, and every 4 years, that 6 hour error is mostly corrected.   Jupiter also accelerates or decelerates the Earth in it's orbit and Earth's orbital speed varies depending on how close to perihelion and aphelion, so there's some variation year to year, but there's no movement across the calendar over 11,000 years.


What is this "hole" that blows sand into the air?

Blowholes are formed through small openings in the ground through which air will blow out or suck in.They have been likened to natural fans or vacuums.Blowholes are dependent on weather: air temperature and pressure interact to create the stunning effects when air travels from higher to lower density. When outside air warms up, it may eventually become the same density as air underground, causing air flow at the blowhole to stop.This outside air continues to warm up, causing air to begin blowing out of the hole.


Round structure in southern United States

This is a sedimentary sequence representing the shoreline of a Cretaceous-Paleogene inland sea, the Western Interior Seaway. You can look at the sequence of sediments laid down in the USGS Geological Map of North America. I recommend downloading the Southern Sheet in high resolution and the Explanation Sheet to explain what's going on.

The land use pattern as seen by other people answering this question is actually putting the effect in front of the cause; due to the nature of these sediments being a positive influence on the fertility of the land, it is more likely to be used for farming.


The bad part about geo-engineering are the unknown unknowns, to paraphrase a certain US politician.

Our climate models are wrong.  All models are wrong, but some are useful..  Our models are useful, but not quite useful enough to trust them when they tell us massively spraying stuff into the stratosphere or the oceans is mostly harmless.  Our models can't properly reproduce our current climate.  They agree about some trends, but there's lots of stuff that they're missing.

We used to use lots of toxic chemicals in our fridges.  That was a bad idea, so we found some stuff that wasn't toxic.  Great, no?  Decades later, scientists realised this was destroying ozone above Antarctica.  At first the measurements were rejected because they didn't make sense.  Contrasted with our understanding of the atmosphere, and why would ozone suddenly disappear anyway?

Our climate system is complex.  Very complex.  Mess with one of the symptoms, and who knows what side effects are going to be?  It's a risk that we cannot quantify, and those are probably the scariest risks out there.  If even with stuff that doesn't seem remotely connected to each other (fridge coolants and ozone) we almost messed up very seriously, who is to say actively messing with our atmosphere or ocean isn't going to have nasty unintended consequences?

Better than offsetting one set of geoengineering (deforestation, ocean acidification, enhanced GHG emissions) with another equally radical one, it might be safer — from a risk management point of view — to try to not do any geoengineering at all.  Certainly as long as our understanding of climate is just starting.

To borrow an analogy from medicine: preventing is better than curing.  Patients are sometimes prescribed medicine where the side-effects are so bad that they're almost lethal by themselves, but only when the patient is surely terminally ill, so there is "nothing to lose".  We do have a lot to lose on Earth.

Note that weather models are initial value problems and climate models solve boundary value problems, so mathematically speaking, the two are completely different.


This methodology won't work. Haude's method only gives a rough estimate of evaporation. Consider the hydrologic cycle: Rainfall = evaporation (or evapotranspiration) + runoff + surface detention + soil moisture storage + infiltration +/- interbasin transfer. It sounds like you don't have nearly enough data to estimate the aquifer recharge.


Some books are about specific parts of the Andes, for example - The Geology of Chile (Mareno and Gibbons - editors). This book represents a culmination of research in tectonics, geology and such from researchers across Chile.  Given the location of Chile, this is definitely an apt reference.

A comprehensive resource is the book Tectonic Evolution of South America (edited by Cordani et al. 2000), this brings together data, information and observations from dozens of scientists across South America.

A paper that is involves a study related to your query is Andean tectonics as a cause for changing drainage patterns in
Miocene northern South America (Hoorn et al. 1995) - this looks at the palaeodrainage of the northern portion of South America in the relation to the mountain building and tectonics of the region at that time.

Another paper, is The proto-Andean margin of Gondwana: an introduction, this introductory paper reviews the evidence for Andean tectonics and palaeotectonic regimes, stretching back to the Neoproterozoc.


Unlike the East African Rift system, it is not possible to view the rifting crust of the West Antarctic Rift directly due to the extensive ice cover over the region (1). However, scientists can and have inferred the nature of the rifting from other methods, including seismic, radar sounding, geodetic methods and by examining the petrology of exposed rocks in surrounding areas. Also, of significance, are observations made of glacial activity, particularly of the prominent Thwaites Glacier (2).

There seems to still be some uncertainty as to the nature of the current tectonic status of the West Antarctic Rift.

On one hand, observations of radar sounding and subglacial water routing at the base of the Thwaites Glacier show some melting that Schroeder et al. (2014) (2) suggest that the melting is due to a geothermal flux that is consistent with magma migration and magmatism, they record a minimum average geothermal flux of ~114 mW/m2, with some areas peaking at >200 mW/m2.  Petrologic observations by Martin et al. (2014 (3) based on samples of of Cenozoic outcrops of surrounding exposed areas on the shoulder of the West Antarctic rift system suggest active rifting with mantle 'refertilisation'.

On the other hand, seismic observations from authors such as Lough et al. (2013) (4), match geodetic data from the POLENET (5) program suggest that much of the rift is not presently active.  Although several earthquakes have been recorded in West Antarctica, very few occur in the rift itself, and these tend to be much smaller magnitude.  Lough et al. (2013) suggest that some of the shallower quakes occur due to glacial activity.

The seismicity further reinforces the conclusions made by Winberry and Anandakrishnan (2003) (6) that the earthquake pattern suggest that the West Antarctic Rift is a dormant rift system, with a possible hotspot origin for volcanic activity occurring in the nearby Marie Byrd Land (1).

The evidence suggests that the West Antarctic Rift system is either dormant, or a very slow moving one.

References

(1) Winberry and Anandakrishnan, 2004, Crustal structure of the West Antarctic rift system and Marie Byrd Land hotspot Geology

(2) Schroeder et al. 2014, Evidence for elevated and spatially variable geothermal flux beneath the West Antarctic Ice Sheet, PNAS

(3) Martin et al. 2014, Increased mantle heat flow with on-going rifting of the West Antarctic rift system inferred from characterisation of plagioclase peridotite in the shallow Antarctic mantle Lithos

(4) Lough et al. 2013, Subglacial volcanic seismicity in Marie Byrd Land detected by the POLENET/ANET seismic deployment American Geophysical Union, Fall Meeting 2012

(5) POLENET

(6) Winberry and Anandakrishnan, 2003, Seismicity and neotectonics of West Antarctica Geophysical Research Letters


There are at least 2 books that come to mind:

National Geographic Readers: Rocks and Minerals (2012), a richly illustrated guide for kids.
Ultimate Explorer Field Guide: Rocks and Minerals (2016) by Nancy Honovich, a guide focussed on getting kids outside, looking at rocks in their backyards and on the camping.

Considering you're in the UK, afterwards I'd start with some experiments about limestone. National Geographic used to have rock kits for kids, not sure who else sells them near you. With the keywords "rock kit kids uk" I get some results that may be worth a look at.


Is there a name for the great circle where latitude and longitude are equal?

The curve where latitude and longitude are equal is not a great circle.  But as joe khool writes in his excellent answer, it's called the curve of Viviani!  It's easy to see that the curve is not a great circle, because, using naïve spherical coordinates (in radians) $(\phi,\lambda)$ with $\lambda$ being longitude and $\phi$ being latitude (zero at equator), this curve passes through $(0,0)$, and also through $(\pi/2,\pi/2)$ which is the north pole ($(\pi/2,\lambda)$ is the north pole for any $\lambda$),  But it also passes through, say, $(1,1)$ which is not on the great circle the between previous two points.

In fact the curve you get looks like this:

Note. I plotted this by defining Cartesian coordinates in the obvious way:

$$
\begin{align}
 x &= R\cos\phi\cos\lambda\\
 y &= R\cos\phi\sin\lambda\\
 z &= R\sin\phi
\end{align}$$

and then plotting $(x,y,z)$ for $\phi = \lambda$ and $\lambda\in[-\pi/2,\pi/2]$.

An earlier version of this answer plotted $(x,y,z)$ for $\phi = \lambda$ and $\lambda\in[-\pi,\pi]$.  This means that $\phi$ takes values which are not in $[-\pi/2,\pi/2]$ of course.  I had assumed that these points would end up around the back of the planet: that you'd get a kind of 'S' which wraps around the planet, but in fact it ends up around the front of it again:

This surprised me!


First, a distinction between "gravity" and "gravitation" as used in geophysics. "Gravitation" pertains to Newton's law of gravitation. (Nobody uses general relativity to model gravitation for small, lumpy masses such as the Earth, Mars, or the Moon.) "Gravity" pertains to how things appear to fall from the perspective of an observer fixed with respect to the rotating Earth. Thus gravity includes gravitational acceleration (inward, more or less toward the center of the Earth) and centrifugal acceleration (outward, away from the Earth's rotation axis). This question is asking about gravity rather than gravitation.

As I understand to compute vector of gravity not saficient to compute normal to elipsoid, but we need to computer normal to geoid (by definition geoid is a surface to which the force of gravity is everywhere perpendicular).

It's the other way around. The geoid is a calculated surface. Before the satellite era, one of the key sets of inputs to the calculation of the geoid were observations of deviations of local gravity, particularly the deflection of the vertical. Which way gravity pointed at several locations gave clues as to the local shape of the geoid.
Observing the orbits of satellites provides a global measure Earth's gravitational field. Satellites have been specially constructed for this job, most recently, GRACE and GOCE. The Earth's gravitational field is published in terms of spherical harmonics coefficients. The gravitational vector for a point in space on or above the Earth's surface can be calculated directly from these coefficients. Vectorially adding in the centrifugal acceleration due to the Earth's rotation results in the gravity vector. The position also yields the nominal gravity vector assuming an ellipsoidal Earth.

So I have some questions:

How to compute normal to geoid?

As noted above, a geoid is not needed. Modern models of the geoid are calculated from those same spherical harmonic coefficients (plus Earth rotation) that used needed to calculate the gravitational acceleration and gravity.

What is the maximum discrepancy of angle between elipsoid normal and geoid normal?

The technical term is "deflection of the vertical" (with variations). Per Hirt et al., it's up to 100 seconds of arc, about 10 kilometers south of the peak Annapurna II. This is a calculated value based on various satellite models (which are a bit coarse) coupled with digital terrain maps coupled with some more hairy mathematics to create fine-scale models.
C. Hirt, et al., “New ultrahigh‐resolution picture of Earth's gravity field,” Geophysical Research Letters, 40.16 (2013): 4279-4283.


Is there a differential angular rotation on Earth?

The Earth's atmosphere rotates at more or less the same rate as the Earth as a whole. Note my use of "more or less". That does not mean exactly the same.

The air does rotate pretty much at the same rate as the Earth near the equator. These are the doldrums. Getting stuck in the doldrums was a big problem for ships in the days when ships used sails.

Moving northward or southward, the air near the surface of the Earth tends to rotate slightly less than the solid Earth's rotation rate. These are the trade winds. Sailing ships used the trade winds to go from Europe to the western hemisphere. The coriolis effect means that the trade winds stop at about 30° north and south latitude. These are the horse latitudes, another area where the atmosphere pretty much does rotates with the Earth. Sailing ships had problems here, too.

Moving even further north in the northern hemisphere / south in the southern hemisphere brings one to the region where surface winds blow predominantly from the west, so faster than the Earth's rotation rate. Sailing ships used these winds to return to Europe from the western hemisphere. Finally, even further from the equator (at roughly 60° north or south latitude), yet another transition occurs. This is the polar cell.

  So, my question is anyone aware of the differential angular rotation on Earth as a result of solid earth and fluid atmosphere interaction?

I mentioned sailing ships. People have been aware of how the winds blow locally since sailing started. People probably started sailing before they started writing. The Portuguese discovered the importance of the trade winds before Columbus sailed to the Americas.

So far I've only written about winds near the surface. The winds are different well above the surface. There are jet streams at the boundaries between where the trade winds and prevailing westerlies flow and at the boundaries of the polar cells.

The Japanese discovered these jet streams during World War II and used this to their advantage. They launched fire balloons from near Tokyo to drop a bomb on the US about three days later. Nowadays, we use the jet streams for more peaceful purposes.


How to find Cloud cover data in GFS grib models

This is not an explicit answer but might give you an idea. The US National Weather Service forecasters use a tool called GFE to create gridded forecasts, largely starting from raw model data. For most models, even those that have TCDC as an output field, the model sky cover grids are computed by GFE using RH at various levels. For a few of the high resolution mesoscale models, the sky grids use the model cloud cover field and the resulting values are either 0% or 100%. Thus a blend of these differing sources can be used to get a more nuanced output forecast.


Difference between Meteosat and Insat satellite Images

Meteosat:-

The Meteosat series of satellites are geostationary meteorological satellites operated by EUMETSAT under the Meteosat Transition Programme (MTP) and the Meteosat Second Generation (MSG) program.

INSAT:-

INSAT-3D is the first Indian geostationary satellite, equipped with sounder instrument that provides frequent good quality atmospheric profiles (temperature, humidity) over Indian landmass and adjoining areas.

More information is here: Two generations of active Meteosat satellites, Meteosat First Generation (MFG) and Meteosat Second Generation (MSG), providing images of the full Earth disc, and data for weather forecasts.

and here: INSAT-3D, Advanced Weather Satellite, Completes Two Years in the Orbit.


What is the nature of the "unexpected geomagnetic pulse that took place beneath South America in 2016"?

The "geomagnetic pulse" here refers to a series of academic works studying the Earth's core such as this open access article (other related articles require scientific journal subscriptions to read).

Geomagnetic pulses have been associated with "geomagnetic jerks". A jerk was reported (yay for open access again) to have occurred in 2014, the 2016 pulse under South America is believed to be related to this, both events having been measured and identified after the fact.

The magnetic field is always changing - a "pulse" is a quicker-than-normal (few year) acceleration of magnetic field change in time, in a region at the surface of the Earth's outer core (magnetic field is generated within the core).

A "jerk" is a quick change (few months) of the rate at which magnetic field changes at Earth's surface, making something like a 'V' shape if you plot the field against time at a given location.

The idea is that a pulse occurs at the core, and jerks are an effect seen at the surface just before and after the peak of the pulse, as the field change ramps up and down. The underlying cause of this is not known, and we only identify them after they've occurred, so they're currently unpredictable. That said this behaviour is apparently part of the core's repertoire, and pulses and jerks have been observed before.


Why do felsic materials have lower melting points than mafic?

Good question! As you know, Bowen's reaction series describes the order of crystallization of silicate minerals in a cooling magma.

The complex anion of silicates is a tetrahedron of four oxygen atoms surrounding one silicon atom, connected with strong covalent bonds. Each tetrahedron may be isolated from one another or they may be bonded together covalently by sharing oxygen atoms between adjacent tetrahedra. In this way they may form single chains (pyroxene), double chains (amphibole), sheets (biotite), and three-dimensional networks of interlocking tetrahedra (quartz).

Each of these covalently bonded structural groups (except 3D networks) is bonded to its neighboring structural group (e.g. single chain to single chain) by ionic bonds with intervening cations (K+, Na+, Ca2+, Mg2+, Fe2+, etc.).

Relatively speaking, covalent bonds have lower melting points than ionic bonds. Source

In Bowen's reaction series, the minerals that form at the cooler end of the discontinuous series are richer in silicon and oxygen and poorer in metal cations. Therefore, the minerals at the cooler end are also more dominated by covalent bonds over ionic bonds. This prevalence is the reason why felsic minerals melt at lower temperatures than mafic ones.

Your logic is correct when looking at mineral stability in the face of chemical weathering. At the Earth's surface, those covalent bonds are much more stable and minerals like quartz tend to be much more resistant to weathering than olivine or pyroxene. This is described in the Goldich stability series, which I like to think of as Bowen's reaction series stood on its head.