Given your description of the base rock and the age of the mine I would suggest that what you are seeing is what in a cave we would refer to as flow stone (A deposit of Calcium Carbonate in one or more of many crystal structures).

Simplified Process:

Ground water often has varying degrees of dissolved carbon dioxide in it.  This carbon dioxide within the water creates a mild acid, carbonic acid.  The acid in the ground water will corrode out Calcium Carbonate in the base rock.  Most ground water will be saturated with Calcium Carbonate, the lime, depending on the concentration of dissolved carbon dioxide in the water.  When the water seeps out of the walls of the mine it has an opportunity to off gas some of the dissolved carbon dioxide.  When this occurs the water can no longer hold as much dissolved Calcium Carbonate and the excess is deposited on the walls in various forms.  The mechanism of dissolving the rock and re-deposition is driven by various equilibrium reactions( involving temperature, water mixing, partial pressures of the gases...).  A karst hydrologist/geologist would be able to give you much more detailed information on the processes. It is this process that forms caves and causes the formations with the caves to form.

The following web site gives a pretty straight forward explanation of what I believe you are seeing. https://en.wikipedia.org/wiki/Karst


(Related to answers to the question Thermal expansion of Earth, which I only realized after having saved this answer. So, in principle, a double post, but I was asked to undelete :-))
Earth's thermal history may give some hints -- not sure if this is an actual answer to the question. It seems like Earth's radius depends on the layering of mantle convection, and that though there were significant changes during the Archean Eon and earlier, the current and recent (since the late Archean) shrinking rate is slow (a reduction of 12km in radius in 2.5Gy).
Source:
Expanding-contracting Earth by Tsuchiya et al. 2013 in Geoscience Frontiers

Questions that remain:
What about the core ?
And is mass loss or gain from astronomical processes significant enough ?
I would like to add that WGS 84 is a reference ellipsoid, and height values can be (are) given as positive or negative numbers. They can be updated every now and then by satellite. Also, I would assume that tectonic processes or local anomalies may by far outweigh any signal from thermal shrinking over the course of next centuries or even millennia (speculation).


Why does the Hadley cell descend at 30 degrees?

The Hadley cell was proposed and works only for a non-rotating earth. When we consider the earth's spin, we have to consider the Coriolis force as well. Because of this force air cannot travel in one unhindered cell from the equator to pole or back. So there must be an odd number of cells together so that the air rising and falling in the adjacent cells is oriented in the proper direction. Considering the various observations of the Easterly and Westerly trade winds a 3 cell model best explains our atmospheric circulation. The location of the majority of earth's driest and arid regions are located in the areas underneath the descending branches of the Hadley circulation around 30 degrees latitude, which also supports the 3 cell model.

Also watch this video which gives a great explanation to all of your questions with the help of practical experiment and animations.
Atmospheric Circulation Video


If an asteroid strikes a glacier, does it make a print on the land below?

A 10 km asteroid would not only obliterate the section of glacier it hit, but also create a huge crater at the impact site!

The asteroid that created the Vredefort crater in South Africa is estimated to have been 10 to 15 km in diameter. It is also estimated that the initial crater created by the impact, some 2 billion years ago before it was eroded, was 300 km in diameter.

To date, this is the largest recognized asteroid crater on Earth. The crater that was produced by the dinosaur extinction asteroid, in the Yucatan (Chicxulub) was only 180 km in diameter. Interestingly, the asteroid that created that crater was also estimated to be 10 to 15 km in diameter.

The Gosses Bluff Crater, in Australia, is 22 km in diameter and it is estimated to have been created by an asteroid 1 km in diameter. The rim of the crater is still 150 m above the surrounding desert.

Any sizable asteroid will vaporize the section of glacier it hits and create a large crater at the impact site.


Are ice-ages dependent on an un-equal distribution of land-masses?

The Earth's climate switches between "hothouse Earth", where ice is nearly absent worldwide, and "icehouse Earth" where the Earth intermittently has ice that stretches far from the poles. Periods when the Earth is in the icehouse Earth phase are called ice ages. The most recent ice age began about 2.6 million years ago and has not yet ended. We are still in an ice age, as evidenced by the fact that Antarctica and Greenland are still covered by ice. Ice ages last many tens to a few hundred of millions of years.

Ice ages are characterized by glacial periods where ice reaches far from the poles separated by interglacial periods where the climate is a bit more moderate. The glacial and interglacial periods within an ice age last tens to hundreds of thousands of years. The current interglacial period began about 12,000 years ago.  It's the Milankovitch cycles that are responsible for the short duration glacial and interglacial periods within an ice age.

These cycles are still present when the Earth is in a hothouse Earth phase. The Earth was in the hothouse phase for about 250-260 million years before the current ice age. That's 2000 or so multiples of the very longest Milankovitch cycle. The Milankovitch cycles are not responsible for the hothouse Earth / icehouse Earth phases. It's plate tectonics that dictates whether Earth is in a hothouse Earth or icehouse Earth phase.

So what aspects of plate tectonics govern whether the Earth is in a hothouse phase or icehouse phase? Below are a series of images depicting how the Earth looked over recent times.

http://upload.wikimedia.org/wikipedia/commons/thumb/7/73/Blakey_35moll.jpg/640px-Blakey_35moll.jpg
35 million years ago, hardly any ice anywhere.

http://upload.wikimedia.org/wikipedia/commons/thumb/2/2c/Blakey_20moll.jpg/640px-Blakey_20moll.jpg
20 million years ago, just a tiny bit of ice in the very far north and very far south.

http://upload.wikimedia.org/wikipedia/commons/thumb/7/7e/Blakey_Pleistmoll.jpg/640px-Blakey_Pleistmoll.jpg
Current ice age, (~2.6 million years ago to present), with ice sometimes reaching as far as 45° latitude.

Source: Ron Blakey, via wikimedia.org. (Blakey's maps are 1200x600, which is a bit wide. I used the 640x320 previews at wikimedia.org.)

There are two key differences at the boundaries of the Pacific Ocean between the pre-ice age Earth and our current ice age Earth. One is the Indonesian seaway. That closed up 3 to 4 million years ago thanks to New Guinea, Indonesia, and the Malay Peninsula. The other is the Panama seaway. That closed up about 3 million years ago thanks to the formation of the Isthmus of Panama. The closing off of the Pacific near the equator drastically changed the global ocean conveyor belt, which in turn drastically changed the climate of the Earth.

So which of these two seaway closures, if any, is the cause of the most recent switch from hothouse Earth to icehouse Earth? A number of researchers put the blame on the formation of the Isthmus of Panama (Bartoli 2005, Nie 2014). Others claim the closure of the Indonesian seaway was responsible (Cane and Molner 2001, Molner 2008). Yet others say "none of the above" (Lunt 2008). The jury is still out, but note that Smith and Pickering 2003 claim that plate tectonics are responsible for each of the four major icehouses in the last 620 million years.

Bartoli, G., et al. (2005). "Final closure of Panama and the onset of northern hemisphere glaciation." Earth and Planetary Science Letters, 237.1: 33-44.

Blakey, Ron. cpgeosystems.com/paleomaps.html (website)

Cane, Mark A., and Peter Molnar (2001). "Closing of the Indonesian seaway as a precursor to east African aridification around 3–4 million years ago." Nature 411.6834: 157-162.

Lunt, Daniel J., et al. (2008). "Late Pliocene Greenland glaciation controlled by a decline in atmospheric CO2 levels." Nature 454.7208: 1102-1105.

Molnar, Peter (2008). "Closing of the Central American Seaway and the Ice Age: A critical review." Paleoceanography 23.2.

Nie, Junsheng, et al. (2014). "Pacific freshening drives Pliocene cooling and Asian monsoon intensification." Scientific Reports 4.

Smith, Alan G., and Kevin T. Pickering (2003). "Oceanic gateways as a critical factor to initiate icehouse Earth." Journal of the Geological Society 160.3: 337-340.


Could an earthquake on flat land still kill someone without any buildings/boulders or such near by?

Yes, a man in the open sitting on grass could be killed by a magnitude 8 or 9 earthquake, but in the circumstances you describe it would be very unlikely. Not all large earthquakes produce huge rifts on land, but if you were unlucky enough to have one open up beneath you then the chances are you would fall into it. Another danger would be liquefaction. In some places the moisture content of the land is such that although in normal circumstances it is perfectly solid and stable, when subjected to the violent shaking of an earthquake a phenomenon called liquefaction occurs. The ground becomes a sort of quicksand into which buildings can collapse and humans disappear. It is quite rare, however, and fatalities among people are unlikely if they are out in the open where nothing can fall on them, though I dare say a few unlucky ones might have a heart attack. On hard ground,though, even a fit and healthy young man might be severely bruised and shaken in a magnitude 9 quake.


difference between different meteorological models

In general, the relation between the three datasets is as follows:

The simulation model is initiated with a set of boundary and initial conditions, and will on the long-term provide good mean conditions. However, depending on the frequency of data assimilation, the results on short-term time spans can deviate from the observations, due to internal variability of the model. Besides, models aren't perfect and sometimes have biases for some variables.
In contrast, the satellite data provides observations. These are of course limited by technical aspects, but as indicated by the table in Section 3 of the link you provided, the quality of the precipitation measurements is very good. However, satellites often have a poorer temporal/spatial resolution than models (a satellite can't be everywhere at once and depending on the type, cannot measure at a very high resolution).
The reanalysis is a combination of the model simulation and the observations, where both sets are merged (via data assimilation) to provide a coherent dataset. This provides a dataset that can be considered 'pseudo-observations' (they are often used as continental-scale or global scale 'observation' datasets in climate studies), but without the poor spatial/temporal resolution of satellite observations. The biases in the reanalyses should be lower than in the original weather simulation, but may still be present.

Concerning the difference between temperature and precipitation: temperature is much easier to correctly simulate than precipitation (e.g. because of the dry/wet-day transition). As such, on a monthly scale, precipitation biases might be already quite large. For more information on precipitation biases, this paper might be relevant: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010jd014532 (Stephens et al. (2010): The dreary state of precipitation in global models)
In essence, the dataset you want to use should depend on your needs. If spatial/temporal coverage and historical data is the most important, the reanalysis is probably your best choice. If you want to know more about this dataset and its biases, this article is a good starting point: https://hess.copernicus.org/articles/24/2527/2020/ (Tarek et al. (2020): Evaluation of the ERA5 reanalysis as a potential reference dataset for hydrological modelling over North America). Or, if your goal is impact assessment, you might immediately check this one: https://essd.copernicus.org/articles/12/2097/2020/ (Cucchi et al. (2020): WFDE5: bias-adjusted ERA5 reanalysis data for impact studies)


How long does earth take to recover from mass extinctions? What is "normal"?

Mass extinctions are selective: not all living organisms will be affected by it to the same extent. Meaning also that various groups will recover from it at various speed: a group from which half of the species were exterminated by the event will most probably take longer to recover (i. e. reach its pre-event diversity) than a group for which only 10% of the species are gone. And a group for which 95% of the diversity is gone is likely to never fully recover its initial diversity.

If you are looking at the recovery of the ecosystem/biome as a whole, then what is likely to happen is that the extinct species left whole ecological niches vacant, meaning that this vacuum is likely to be quickly filled by new species (either species group that already existed and were already occupying this ecospace but were dominated by the now-extinct species or brand new species group). On that subject, one has to realise also that the recovery of a trophic level of an ecosystem is dependent on the recovery of the others (i. e. and to simplify, recovery of apex predators depends of the recovery of grazers, which depends on the recovery of primary producers etc.), so a mass extinction affecting primarily the primary producers might need longer to recover than one affecting mainly the apex predators.

So is 10 Myr a short amount of time to recover from a mass extinction? I'll say that one would expect ecological recovery to be faster than that (see for instance the speed at which milieux disturbed by glacial episodes recover during interglacials, or the speed at which new islands get colonised). But for the complete recovery of global diversity (in particular for an event supposedly wiping out 90% of life diversity) i'd have expected it to take longer than 10 Myr. In the second article you link, the authors estimate that the recovery of the terrestrial ecosystem is fast by comparison with how long it took to colonise the land in the first place (i. e. 100 Myrs). But all the evolutionary adaptations needed to function on land do not need to be re-evolved, so it seems rational to expect it to take a shorter time than those 100 Myrs... Otherwise the probable reason the news article you linked considered it to be a long recovery time was to emphasise the fact that the article show that it took longer because of ripple effects of the Permo-Triassic event during the early Triassic that slowed down the recovery.

In a review of mass extinction recovery predating those two articles, Erwin (1998) estimated the duration of the recovery from the End Ordovician, Frasian-Fammenian, end-Permian, end-Triassic and K/T extinction events (I mention here only the so-called "Big Five" extinctions) to, respectively, 7, 3, "3 to 9?", 3 and 2 millions years. With those number in mind, then indeed 10 Myrs is a long recovery.

The same article also had this to say about the definition of mass extinction recovery:

  How does one define a recovery? Mass extinctions create new ecological opportunities, and the common-sense definition of a recovery interval encompasses the rapid diversification by surviving lineages following the end of the extinction and ending with either the waning of the rapid, postextinction diversification or the return of normally functioning communities. Normal is hard to quantify, however, even without the extensive disruptions associated with some mass extinctions. Moreover, different clades recover at different rates and the same clade can recover at different rates in different regions. If we accept the recovery as beginning with an increase in evolutionary rates, this usefully distinguishes an immediate, postextinction survival interval, dominated by surviving lineages, from the often exuberant diversifications of the subsequent recovery phase. An alternative definition relies on the 're-establishment of pre-extinction isotopic values and ecosystems that are essentially equivalent to those that existed before the extinction'. Here the emphasis lies equally on the physical environment and the ecosystem recovery.
  Douglas H. Erwing, 1998. The end and the beginning:
  recoveries from mass extinctions, Trends in Evolution and Ecology.

Finally, evolution is non-repeatable: so to answer your question "Let's say some catastrophe strikes and wipes out everything but bacteria - are we likely to see complex life ever again", the answer is that if all eukaryotes are wiped out then no eukaryotes is likely to reappear, but another "complex" group can appear anew (though bacteria are already very complex if you ask me). Similarly if life is completely wiped out I don't think it is reasonable to think it will reappear (in particular because the Hadean/Archean conditions that saw its appearance do not exist anymore).


Are there any uncharted waters left on earth?

There are many "uncharted waters".  Nautical charts have information about water depths, dangers to navigation, aids to navigation, anchorages, and other features.  You can see here what might be included in a nautical chart: U.S. Chart No. 1

The area in question is a shallow sea... so boats of different sizes may or may not be able to take certain routes depending on tides etc.  Thus a nautical chart is important in these types of regions.

Yes satellites have mapped the world... and coastline is well defined.   You can even learn about underwater depths using satellite instrumentation that detects gravity (e.g. CryoSat2) as discussed here: Global seafloor map reveals uncharted sea mountains, stunning details of Earth's oceans which discusses recent measurements of the seafloor from space.

  University of Sydney geophysicist Dietmar Müller said about 71% of the Earth's surface is covered by water and roughly 90% of the seafloor is uncharted by survey ships that employ acoustic beams to map the depths. ... Müller said the conclusions the [satellite] researchers made about seabed topography may be less accurate than acoustic beam methods employed by ships.

and the article Gravity’s Magic: New Seafloor Map Shows Earth’s Uncharted Depths says:

  The effect of the slight increase in gravity caused by the mass of rock in an undersea mountain is to attract a mound of water several meters high over the seamount. Deep ocean trenches have the reverse effect,” ESA wrote in a statement.  “These features can only be detected by using radar altimetry from space.


How to derive the total potential energy of the atmosphere?

First, let's acknowledge this fact: $$c_p=R+c_v \tag{1}$$,
where $R$ is the specific gas constant.
This means that $x=R/c_p$.
Rearranging the equation, we can see that $$P+I=\int{c_p\left(\frac{P}{P_{00}}\right)^{R/c_p}\Theta dM}\tag{2}$$
Notice that $\left(\frac{P}{P_{00}}\right)^{R/c_p}$ is the Exner function. By extension,$$P+I=\int{c_p T dM}\tag{3}$$ If we rearrange (1) we can get
$$P+I=\int{c_v T+RT dM}\tag{4}$$.
You observed correctly that $I=\int{c_v T}dM$. This leaves $$P=\int{RT dM}\tag{5}$$.
Using the ideal gas law,$$P=\int{P\alpha dM}$$, where $\alpha$ is specific volume. This makes (4) look like $$P+I=\int{c_v T+P\alpha dM}\tag{4}$$ which is just a restatement of the first law of thermodynamics: $\delta q = c_v dT + p d\alpha$


Carbon dioxide and ocean acidification based on temperature

From Sabine, et al., 2004:

  The capacity for ocean waters to take up anthropogenic CO2 from the
  atmosphere is inversely proportional to the value of the Revelle
  Factor, hence the lower the Revelle Factor, the higher the oceanic
  equilibrium  concentration of anthropogenic CO2 for a given
  atmospheric CO2 perturbation.

The Revelle Factor is, "the ratio of instantaneous change in carbon dioxide to the change in total dissolved inorganic carbon (DIC)"

Therefore, the controlling factor for CO$_2$ absorption in seawater is presence of DIC and buffering. If you add CO$_2$ and a relatively small portion of it becomes other DIC species such as HCO$_3^{-}$ or CO$_3^{2-}$, then you have a low Revelle factor and high uptake of atmospheric CO$_2$. Alkaline waters (lower pH) can absorb more CO$_2$ because they have less of the acidic CO$_3^{2-}$ and neutral buffering HCO$_3^{-}$.


Do Earth's layers move at different speeds?

Im am currently doing my masters in geophysics (last semester) and before that I did a bachelor in geoscience.

I assume by layers you mean the crust, the mantle and the core.
These all have different composition and also different densities. But the earth rotates as a whole, not the individual layers, all layers have the same angular velocity. That means they all make one rotation per day.
These layers are also not the perfect boundaries we like to imagine, but more a change in properties around a finite depth. This depth can even change at different places.


How to calculate Wind direction from uwind and vwind?

The base formula for the direction $\theta$ is

$\theta=atan2\left(\frac{\text{uwind}}{\text{vwind}}\right)$

Where $atan2$ is the four quadrant inverse tangent. Note that if you used the normal inverse tangent your results will be all collapsed to the first quadrant (0° to 90°). Also note that depending on the platform the result can be in radians or degrees (most often in radians, some platforms have a function atan2d that return values in degrees).

If you get a negative value (which is the same direction but measured counterclockwise), you have to add 360° (or $2\pi$ radians).

This will give you the direction the wind is coming from. For the direction is going to, you have to add/substract 180° (or $\pi$ radians).

For the values you provide, the answer would be 210°.


Short answer: UT1

Long answer:

The Julian Day (JD) is just a consistent day count since the beginning of the Julian period, that is January 12th 4713 BC. As the numbers tend to be large (today is day 2,458,557.5), in the 80's and motivated by computer memory limitations, the reduced JD was created which is just $JD-2400000$. Then, to remove the annoyance that the Julian Day starts at midday instead of midnight, the Modified JD (MDJ) was created, which is just $JD-2400000.5$.

By definition the MJD zeroes at solar noon at the 0° meridian. Therefore, it is not a regular time measure, it is tied to Earth's rotation and accelerates or decelerates depending on minute variations of Earth's rotating speed.

You can use basically any solar time including all flavors of UT time to define your MJD, but the most precise is UT1.

But UT1 is not a regular measure of time either, and is also affected by variations on Earth rotation speed. The only really regular time standard among the ones you mention is UTC, which is based on atomic clocks. Being regular, the solar noon drift off UTC and doesn't happen at 12:00 h UTC, therefore, leap seconds are added to keep UTC reasonably close to solar time. But a record of leap seconds is kept so you can use UTC to precisely measure time intervals independently of the variations of Earth's rotation.

In that sense UT1 and UTC are not two flavors of the same thing as you suggest, they actually measure two completely differing things. The first measure Earth's rotation and the second measures time. Due to the same reason, MJD cannot or should not really be referenced to UTC (otherwise it would not zero solar noon).

Said this, in those bulletins the MJD conveys exactly the same information than the date. So "2019 1 2" meaning January 2nd 2019, conveys exactly the same information than MDJ 58485, it is just a more machine friendly way to refer to a specific day. And it also removes the need to account for missing calendar days if you work with dates relatively far in the past.

Now if you want to know how much time have elapsed between two entries in the table, you need to know how to transform whatever version of solar time they use (UT1 in this case), to a regular time reference like UTC or TAI. That's why the "UT1-UTC" value is included. In any case, in doing such calculation you need to take in account any leap seconds added to UTC between the time of the two entries.

Does that makes sense?


How is the mass of the Earth determined?

According to Newton's Law of Gravity based on attractive force (gravitational force) that two masses exert on each other:
$$F=\frac{GmM}{r^2}$$
Where:

$F$ is the gravitational force
$G = 6.67 \times 10^{-11}\ \mathrm{m}^3\ \mathrm{kg}^{-1}\ \mathrm{s}^{-2}$ is a constant of proportionality
$M$ and $m$ are the two masses exerting the forces
$r$ is the distance between the two centers of mass.

From Newton's second law of motion:
$$F=ma$$
Where:

$F$ is the force applied to an object
$m$ is the mass of the object
$a$ is its acceleration due to the force.

Equating both the equations:
$$F = \frac{GmM}{r^2} = ma$$
$$\frac{GM}{r^2}= a$$ (The $m$'s canceled out.)
Now solve for $M$, the mass of the Earth.
$$M = \frac{ar^2}{G}$$
Where $a = 9.8\ \mathrm{m}\ \mathrm{s}^{-2}$, $r = 6.4 \times 10^6\ \mathrm{m}$, and $G = 6.67 \times 10^{-11}\ \mathrm{m}^3\ \mathrm{kg}^{-1}\ \mathrm{s}^{-2}$.
$$M = 9.8 \times (6.4 \times 10^6)^2/(6.67 \times 10^{-11})\ \mathrm{kg}$$

Hence,
$M = 6.0 \times 10^{24}\ \mathrm{kg}$


How to run earth system, land surface and climate models?

As alluded to in some of the comments, all of the CMIP5 models will have been run on supercomputers, and it takes a lot of effort to get one of them running on a new platform, even for a team who know both the model and platform well already.  In addition to that, many of those models are closed-source and are not generally available to an individual researcher.  However, there are several older models such as MITgcm and EdGCM that it might well be possible to get running on a cluster.  It's something I've thought about but never quite got around to.  One group have even been
running CESM on Amazon's EC2 service.

Depending on what aspect of leaf phenology you're interested in, you may need to run quite long simulations (e.g., several centuries), which is prohibitive with a full ESM.  You can make a lot of progress in this area by running just the land surface components.  This is several orders of magnitude simpler than running an ESM: the source codes are often freely available where their host ESM code is not, and they can be run globally on desktop machines or clusters.  Some example land surface models you might want to look into:

Community Land Model (CLM) (used in CCSM, US)
JULES (used in HadGEM, UK)
CABLE (used in ACCESS, Aus)
ORCHIDEE (used in IPSL-CM5, Fr)
SURFEX (used in CNRM-CM5, Fr)

Each of these will require a set of forcing boundary conditions, and there are several commonly used by the land community:

GSWP3
WFDEI
CRU-NCEP
Princeton

If you go down the land surface route (and I suggest that's a good place to start), you should probably just pick a model and ask it's community directly about the details of getting it running.  In my experience, several of them have very good tutorials especially for people with a bit of Linux experience.


If we assume the mega impact hypothesis for the formation of Moon, where on Earth is the impact point?

I think you are confused about the timescales and the magnitude of the impact that is being talked about here.

The collision between the early Earth and a roughly Mars sized body, Theia is thought to have happened between 4.4 and 4.45 billion years ago. The Pangaea supercontinent had fully assembled by around 250 million years ago. Previous to this there are a number of other supercontinents which have been recognised, the oldest speculative ones dating back to around 3 billion years ago. The Earth's crust is constantly being reshaped by plate tectonics and so the location of an impact at 4.4 billion years ago has no bearing whatsoever on the orientation of the Pangaea (or any other) supercontinent.

In addition, based on computer simulations of the impact, we know that the impactor mass must have been on the order of 0.1 Earth masses and the initial impactor velocity must have been something like 5 km/s. This means that a colossal quantity of energy would have been released by the impact which would completely reshape any surface structure (and much of the internal structure) that the Earth may have had at that early stage. Indeed, a significant quantity of the mass of the two impactors was put into orbit around the Earth by the impact, either as solid debris, some of which coalesced to form the Moon, or as vaporised rock. Due to the complete lack of direct evidence, it is difficult to determine the exact impact parameters, including the impact angle. Some simulations suggest a fairly moderate angle of impact of around 45° [1], but there is some geochemical evidence from the Moon to suggest a higher angle of impact, with higher energies involved [2][3].

References:
  [1] http://www.sciencedirect.com/science/article/pii/S0019103503002999
  [2] http://science.sciencemag.org/content/351/6272/493.full
  [3] http://science.sciencemag.org/content/338/6110/1052.full


Why does dew accumlate on only one side of my car?

The formation of dew is due to atmospheric moisture and temperature.

Given that dew forms on all sides of your car at your mother's house, this makes me think the car is more exposed at you mother's house so that the car is uniformly cold and the temperature of the car is at, or below, the dew point.

With dew only forming on one side of the car when at your father's house, this tends to infer there is a temperature difference between each side of the car; with the side of the car on which due forms being colder.

You mention that dew does not form on the side of the car facing a tree. If the tree is sufficiently large and leafy (bushy) and the car is close enough to the tree, the tree can shield the car from the cold air thus making that side of the car slightly warmer than the other side of the car. As long as the temperature is above the dew point, due will not form.

Dew point varies for atmospheric moisture content, temperature and air pressure.


How to get the exact temperature from 1880 to 2020?

I assume is an annual temperature change relative to the previous year.

No, that would be called the rate of change. "Anomaly" means the difference from some reference temperature.


I think you have drawn the 'short straw'! As disasters go, volcanoes have about the least to do with human activity. Basically, volcanoes are the product of plate tectonics, which operates on a scale vastly greater than human impacts on the planet. At least one book has been written about earthquakes, volcanoes and human impacts, but the linkage is tenuous at best. The argument goes something like this: Humans modify the water table by pumping, diverting water, building dams, etc. Also by human-induced climate change contributing to rising sea levels. Increased hydrostatic pressure in the ground 'lubricates' fault planes causing lesser but more frequent earthquakes. In and around volcanoes, there is more groundwater which increases water vapour in/near magma chambers, and hence increases the activity of volatiles, contributing to volcanic eruptions.

This is all speculative, and most geologists doubt whether these effects are significant, or even if they exist at all. I think you will have a hard task trying to provide supporting evidence for any of this.

On the other hand there is passive interaction in that many terrestrial volcanoes in wet climates produce vast quantities of volcanic ash that weathers rapidly to produce fertile soil. This fertility attracts farming communities who put themselves in harms way, being at risk from hot ash clouds, hot lava, volcanic bombs and mudflows. The latter are produced by hurricane level rainfall mobilizing the loose ash, such that mudflows (or 'lahars') kill far more people than the volcanoes themselves - we have seen many examples in the news in recent decades - in South and Central America, Indonesia, Philippines, etc.

The Mount St. Helens eruption was caused by the Juan de Fuca tectonic plate subducting under North America. It's a 100% natural process, with no human causation whatever.

There are no known cases of fracking having any impact upon volcanoes. Can you imagine any fracking company taking the legal risk of setting off a volcanic eruption? In any case, the basic geology of volcanoes and hydrocarbon bearing sediments is quite different.


Is there a difference between rock and stone?

I'm quoting from my old The Penguin Dictionary of Geology by D. G. A Whitten &
J. R. V. Brooks, published in 1979.

  Rock (1) To the geologist any mass of mineral matter, whether consolidated or not, which forms part of the Earth's crust ... (2) The
  civil engineer regards rock as something hard, consolidated, and/or
  load bearing, which, where necessary, has to be removed by blasting.
  This concept also accords with the popular idea of the meaning of the
  word.

  Stone In geology the word 'stone' is admissible only in combinations such as limestone, sandstone, etc., or where it is used
  as the name for extracted material - building stone, stone road. It
  should not be used as a synonym for rock or pebble.


Is there an instance where the sun sets or rises partly, then return back?

Yes, such sunrises happens every year at the beginning and end of the polar nights at high latitudes. One can have a few days with a glimpse of the sun but disqualified sunsets and sunrises.

Sunsets occur at the end of the midnight sun period by the end of the summer, the first sunset is not complete.

Sun at it's highest elevation at midday. (To be honest, the picture might be taken the day after the first sunrise, as some mountains are hiding the horizon.)

Here is e.g. an article from Svalbardsposten, the northernmost newspaper in the world, reporting of the first rays of sunlight after the polar night and some pictures from the last sunrise/sunset before the polar night in northern Sweden.

The same occurs at the southern polar circle and south thereof, unless it's cloudy...

Update: here is a great time laps from Davis Station in the Vestfold Hills showing exactly what you asked about: Mid winter


Regarding subdomains - I expect that there may be hundreds or thousands of subdomain *spheres.

For example, I've studied soil for many years and had never heard of the "drillosphere", "porosphere", "aggregatusphere", or "detritusphere".

  “drilosphere” (the portion of the soil volume influenced by secretions
  of earthworms), the porosphere (the total pore space), detritusphere
  (dead plant and soil biota), aggregatusphere (the sum of aggregates)
  and the rhizosphere.

from fig 4 in the same Nature Education article that provided the macro-view venn diagram in @blunders' answer.

(source: nature.com)


Botryoidal habit describes the arrangement of a large group of hematite crystals.

While hematite's trigonal crystal system describes the geometry of a single unit crystal of hematite,  the two terms are really not related at all. Many minerals with different crystal systems can have a botryoidal habit.

The difference between a Botryoidal habit and mineral's unit crystal geometry is a difference in scale. A botryoidal habit can be measured in inches to feet while crystal geometry is measured in Ångstroms.


Applications of differential/integral calculus in crystallography (teaching undergraduates)?

This site may give you some ideas. In particular, look at the Petrology and Geochemistry section:

  Metamorphic phase diagrams show which minerals are stable under
  various temperatures and pressures. The slopes of the boundaries
  between the areas where different minerals are stable depend on the
  properties of the minerals (like the entropy and the molar volume).

  And... well, mineralogy, petrology, and geochemistry are full of ideas
  taken from chemical thermodynamics. And thermodynamics is full of
  multivariable calculus. (How does changing the pressure change the
  amount of calcium in garnet vs the amount of calcium in plagioclase?
  The question is a partial derivative.) From my own favorite,
  metamorphic petrology, there are all kinds of techniques for using
  metamorphic minerals to tell stories of heating and burial and cooling
  and exhumation. And none of the techniques would be possible without
  calculus. (Or, in many cases, differential equations.) I'm sure
  igneous rocks and ore deposits have similar uses of thermodynamics.

Here's an example of a metamorphic P-T Diagram with the source link with more examples:

Source:  https://serc.carleton.edu/research_education/equilibria/metamorphic_diagrams.html


What's the difference between uptake and adsorption of gas into aerosols

Adsorption is adhesion of thin film of liquid or gas on solid substance and the host solid substance does not form chemical bond with deposited material. Uptake is entering of material into substance, end product of which is a solution. Uptake generally happens in liquid host substances but it is also possible for solid host substance to uptake the gas or liquid.

In context of aerosols, the term adsorption is used when solid aerosol particles like dust, soot, ice, etc. are interacting with gases. The term uptake is used when liquid aerosol particle are interacting with gases.

Reference
http://glossary.ametsoc.org/wiki/Adsorption


Derivation of Geomagnetic field lines (after interaction with solar wind)

Short answer: Tsyganenko was not the first to attempt an observation based mathematical model, and older purely theoretical models also exist.
The first mathematical magnetic field model was created from measurements made on Earth's surface by Carl Friedrich Gauss in the 1830s, when he derived the mathematical techniques we still use. For the solar wind and interactions between the Earth's field and the solar wind, we're talking the advent of the space age when we were first able to make measurements out in space and begin to mathematically describe them, though the idea of the solar wind had been suggested (not by that name) in the early 1900s, and theoretical models exist from the 1960s at least.
Wikipedia has a brief summary of the history of major magnetospheric and solar wind discoveries, that suggests things kicked off with satellite measurements made in 1958/9. Tsyganenko cites a NASA study from 1975 as the first empirical model of Earth's magnetosphere and its interaction with the solar wind, though direct measurements apparently weren't made in the magneto-tail until 1983 (from the first Wiki page).
An aside for clarity: the dipolar nature of Earth's magnetic field isn't due to the interaction with the solar wind - the field generated by the geodynamo in Earth's outer core contributes the bulk of Earth's magnetosphere and has a more complicated shape when considered at the Earth's surface, for example.
Magnetic fields have a strong dependence on distance from their source, and smaller spatial features attenuate more rapidly (think like with sound waves - you hear low frequencies far away, but the high frequencies attenuate more quickly), so the approximation as a dipole gets more accurate as you move further away from the source of the field.
So when considering the interaction between the solar wind and Earth's field, which occurs at several Earth radii out in space (the exact distance changes as it depends on the strength of Earth's field pushing out, and the strength of the solar wind pushing back) the Earth's field is roughly dipolar, and then gets distorted with a squashed bow-shock and elongated magneto-tail by the action of the solar wind.


A guide to how climate change will affect different countries

There's a fair bit of unknowns for what you're asking, 300 years and specifics.   For one, climate change modeling is based off CO2 levels and CO2 levels long term are difficult to predict.   That's why they run hundreds of models, each with different circumstances.  Nobody can make an accurate assessment of mankind's CO2 output will be 50 or 100 years so the further out you go the greater the unknowns.  Targets are being set for 2050, but whether they will be reached is a big unknown and I've never seen anything that goes for 300 years.  Most of the models run till 2100.

Some Unknowns:

Will CO2 PPM peak at 500 or 600 or higher?   Will it fall below 400
in 100 years?
Will the oceans continue to absorb CO2 or will they warm to the point
where they stop.
Will the North Atlantic current stop or weaken?   That would have an
enormous effect on European climate.
Will large chunks of ice break off or will the ice sheets remain
mostly intact?

These are impossible things to predict with any accuracy and they significantly effect the outcomes you've asked for.

Smaller effects, such as whether the Sun will enter an extended solar minimum or whether we have a big volcanic eruption like the one in 1815 (which would slow things down for 5-10 years, but wouldn't have a significant long term effect).   Other questions are whether parts of the Earth can be greened, artificially, which might not measurably slow down the warming but it could ease the effects of drought in some areas.

Bottom line is that "basic" predictions might be just as good as detailed because of all the unknowns.   A few aspects are pretty straight forward, like knowing the effect of 1 foot of sea level rise, but predicting how fast the oceans will rise 1 foot is very difficult.   The effects of ocean acidity and some weather driven species migration is somewhat predictable too.   Predicting where droughts are more likely to happen can be done as well, but as I said above, might be preventable with strong irrigation efforts.

Rough predictions aren't hard to find, but for the 21st century only.  Anything further out than that is probably lots of guesswork and not carefully modeled.    Basic and this century is probably as good as this field of study gets.

Articles here and here.  I imagine those are both based on the 5th assessment report.

footnote:  If you read assessment reports online, keep in mind the labeling system - 5th; AR5,  4th; AR4, 3rd; TAR, 2nd; SAR, first; FAR.  Given how fast this field tends to update, I'd mostly just read IPCC reports labeled AR5, perhaps AR4.   Anything before then is quite dated by now.


The Southern Ocean does have its own current, the Antarctic Circunmpolar Current.

It helps generate the Circumpolar Deep Water due to density gradients. Ice melts and thus salinity decreases. Differences in salinity are the reason for bulk water movements in the ocean.

Thus the Southern Ocean contributes to cool the Earth.

Geographical criteria may be open for discussion, but oceanographically speaking it is a separate system from its neighbors, the Atlantic, Pacific and Indian.


How can there be a hot summer with rain and no thunderstorms and lightning?

This is an El Nino summer, and a very strong one and a very weird one at that. Weather patterns are messed up world-wide. Apparently a stable high pressure cell has set up that oscillates back and forth between just east of Barcelona to eastern Europe.

France suffers when that high pressure cell is just east of Barcelona. That high pressure cell off Barcelona means France is in that thick of it. Moderately high temperatures and low humidity rule the day. The chance of rain is drastically reduced, and the chance of abnormal high temperatures is drastically increased.

France suffers even more when that high pressure cell migrates to the northeast. Now the clockwise rotation of the high pressure cell carries extremely hot and extremely dry air from the Sahara towards France. If on the very odd chance that you do see clouds, and on the odder chance that you do see rain falling from a cloud, the odds are that you'll see the rain disappearing halfway to the ground.


Why is the outer color of a rainbow red?

Rainbows are created under certain light conditions when water droplets in the atmosphere act like a prism and refract sunlight.

Light is part of the electromagnetic spectrum which covers electromagnetic waves from radio waves with a wavelength of 1000 m (long wavelengths) to gamma rays with wavelengths around 0.01 nm (short wavelengths).

Sunlight is composed largely of all the colors of the spectrum of visible light. When our eyes see all the colors at once, our brain interprets the color as being "white light".

When humans see a red object that object reflects red light by absorbs all the other colors of light.

In the spectrum of visible light, red light has the longest wavelength of 700 nm and violet light has the shortest wavelength of 400 nm.

When light enters a water droplet in the atmosphere the water droplet acts like a mini prism. The angle at which the different wavelengths of light exit the prism is determined by Snell's Law and this is why light that exist a prism, or is in a rainbow, is layered into colors with red being the first layer and violet the last.


How to convert the units of specific cloud liquid water from ERA5 (kg/kg) to kg/m2?

I got the solution https://www.researchgate.net/post/How_to_convert_the_units_of_specific_cloud_liquid_water_from_ERA5_kg_kg_to_kg_m2

and

https://www.nwpsaf.eu/site/download/documentation/rtm/docs_rttov12/rttov_gas_cloud_aerosol_units.pdf

In the above link the conversions between $\small\mathsf{kg/kg}$ , $\small\mathsf{g/m^3}$ , $\small\mathsf{kg/m^2}$ can be explicitly derived

EDIT
The summary of the first hyperlink is:

  $\small\mathsf{kg/kg}$ stands usually for kg liquid water per kg air.
  Multiplying the term with the calculated air density within the field will result into $\small\mathsf{kg/m^3}$, which means kg liquid water per $\small\mathsf{m^3}$ air. Then you have to multiply with the thickness of the liquid cloud, which will result into $\small\mathsf{kg/m^2}$."


Are "rainy season" and "less rainy season" good ways to describe Amazon seasons in English scientific language?

Dry season

While not being very descriptive, 'dry season' is in general use, even for rainforests (Af Koppen climate, if you will). Example papers using the terminology here.


Using Range Height Indicator scan of radar

A vertical cross section in RHI mode reveals vertical structure that you can't directly observe in a horizontal PPI scan.  In the image below you can clearly see that there is a significant bounded weak echo region (BWER).  You could put this together from PPI scans at different scan elevations combined for a 3D view but with RHI you can see this from a single scan.  You can also get a sense of the anvil structure as shown in the image below.

Whether you can determine anvil rain or structure is going to be affected by the particular radar and where it is located.  Each radar band has pros/cons related to detection and attenuation but if you take these into account then you could be able to determine the features you are interested in.  You should also be able to observe Doppler winds in RHI and if you are doing this in the field with research radars it is a good bet you have dual-polarimetric data as well.

Here is a presentation of RHI scans in supercells with dual-pol data.


How much have global GPP and biomass changed over Earth's history?

To answer your question to the point: we don't know at all.

For most of living organisms, the fossil record is either inexistent or very fragmentary. Even estimating the number of species (which is somewhat less difficult since you need only one specimen of each species to have access to that information) is very difficult and affected by many, many biases (see the works of Jack Sepkoski, David Raup and John Alroy for instance, to see the difficulty of estimating past biodiversity). Attempts at reconstructing marine "invertebrates" diversity (Sepkoski 1978; Alroy et al. 2001, 2008) showed an increase during the Phanerozoic (so, give or take, the last half-billion years), with five main mass extinction events (End Ordovician, Late Devonian, Permian/Triassic boundary, Triassic/Jurassic boundary and Cretaceous/Paleogene boundary).

The general assumption is that biomass increases when diversity increase. There is frankly not very strong basis for this assumption but that's basically all we can work with.

Some living organisms however have a much better fossil record: diatoms, radiolarians, foraminifera and calcareous nannofossils (mainly from the algae group of the Haptophyta) constitutes the bulk of marine sediments and are therefore recorded consistently and abundantly. Their Cenozoic record (i. e. the last 66 Myr) in particular is remarkably complete, but still in some cases biased enough to prevent us for estimating reasonably changes in their abundance.

As a matter of fact, my current research revolves around the changes in diatom abundance in sediments during the last 50 Myrs (Renaudie 2016). Without going too much into the details, it seems, in that case, that their abundance (in sediments at least) and their diversity are more or loss synced. The interest of diatoms, in regard to your specific question, is that, today, there are one of the two main oceanic primary producers (along with Haptophyta), oceanic production itself being more or less half of the global production (see this previous answer of mine). Their abundance increased significantly at the Eocene/Oligocene boundary and then during the Mid-Miocene. Of course it is possible that in the mean time other phytoplankton (Haptophyta, Dinoflagellates, or others) abundance might have dropped but what makes us think that this is not the case is that changes in diatom abundances during the Cenozoic match changes in atmospheric $p\mathrm{CO}_2$ (Beerling & Royer 2011), implying a global increase in the net primary production.

References:
Alroy, J. et al., 2001. Effects of sampling standardization on estimates of Phanerozoic marine diversification. PNAS, 98(11): 6261-6266.
Alroy, J. et al., 2008. Phanerozoic Trends in the Global Diversity of
Marine Invertebrates. Science, 321: 97-100.
Beerling, D. J. & Royer, D. L. 2011. Convergent Cenozoic CO2 history. Nature Geosciences, 4: 418-420.
Renaudie, J. 2016. Quantifying the Cenozoic marine diatom deposition history: links to the C and Si cycles. Biogeosciences, 13: 6003-6014. [Disclaimer: I am the author of this article]
Sepkoski J. J. Jr, 1978. A kinetic model of Phanerozoic taxonomic diversity I. Analysis of marine orders. Paleobiology, 4: 223-251.


Can tides at night by consistently higher than in the daytime?

I find the statement in the question difficult to believe.Tides have a pretty cyclical period and I doubt the resulting effect is a day-night difference unless only S1 and S2 tidal constituents are important in that location, which I find very unlikely.

In fact, the portal
https://www.tide-forecast.com/locations/Fremantle-Australia/tides/latest
shows the high tide being larger during the day for the rest of the month of May 2018.
That behavior changes in time as one would expect. The dominant frequencies at this location are diurnal tides (mostly a single high tide and low tide per day). The main diurnal tides have a period around 24 hours and in this case the dominant periods are slightly larger than 24 hours.

You can download the hourly data from: http://uhslc.soest.hawaii.edu/data/netcdf/fast/hourly/h175.nc
and the resulting time series goes from 1984 to now. Here is the time series for the year 2017. There is no time at which the tide "dissappears".

The resulting harmonic analysis (using t_tide) shows that the tidal constituents with amplitudes over about 5 cm are:

Constituent  Period (h)  Magnitude (m)
   O1         25.82      0.1206
   K1         23.93      0.1667
   M2         12.42      0.0525
   S2         12.00      0.0465

The dominant constituents are K1 and O1, with comparable amplitudes. The resulting effect of the two main diurnal frequencies is a period slightly over 24 hours. The effect of the semidiurnal constituents (M2, S2) is smaller and can be seen in the first time series as slight humps in May 24-27.

T_tide: Pawlowicz, R., B. Beardsley, and S. Lentz, "Classical Tidal
"Harmonic Analysis Including Error Estimates in MATLAB
 using t_tide", Computers and Geosciences, 28, 929-937 (2002).


Why isn't the side of the earth facing the sun completely illuminated by sunlight from the north to the south pole every day of the year?

If the diameter of the Sun is $R_S$, the diameter of the Earth is $R_E$, and the orbital radius of the Earth is $r$, as in the drawing below (sorry about the quality),  then you can do some geometry and compute $\theta$, which is the angle at which the light from the edge of the Sun's disk as seen from Earth is tangent to the Earth's surface referenced to a line between the centres of the Sun and the Earth.

The expression for $\theta$ comes out to be

$$\theta = \sin^{-1}\left(\frac{R_S - R_E}{r}\right)$$

(You get this by extending the tangent line and the line connecting the centres, realising that this makes two similar right triangles with the angle at the tip being $\theta$, and the base of the larger one being $R_S$, then working out what the hypotenuse of the larger triangle is, which gives you $\sin\theta$.)

Since $\theta$ is small we can just say $\sin \theta = \theta$ in the usual way, and plugging in values we get $\theta \approx 0.0046\,\mathrm{rad}$.

If the angle at which the Earth's rotation axis is tilted is more than $\theta$, then there will be a period of the year during which the poles are not illuminated as the point at which the Sun's light is tangent to the Earth's surface is sunward of the pole.  Well, the angle of tilt is $23.5^\circ \approx 0.41\,\mathrm{rad}$, which is about $90\theta$.


Why does seismic activity shed light on the inner core rigidity?

The question that Azzie Rogers linked to: How can we determine the size and composition of Earth's inner core?

Does answer the theory part of the question, but I will extrapolate a little more to answer the question.

The question becomes, what kind of waves travel through what? Both shear and compressional seismic waves can travel through solids, but as it turns out, you cannot shear a liquid. As you look at teleseismic raypaths (waves traveling far from the source) you can see that the wave must travel deep into the earth and then back up again. The wave forms, and directions of these wavepaths will be altered by the different compositions of Earth's layers as it travels through: a wave just traveling through the mantle will have both its shear and compressional component.  A wave traveling through the mantle and outer core will lose its original shear component, and either develop a new one as it leaves the core (but distinct from the wave that travels through the mantle only) or not have one at all. And finally, a wave that travels through the mantle, outer core and inner core will have distinct wave patters as well. Its by this comparison of waveforms that we realize that the earth not only has different compositional layers, but phase boundaries as well. I am not sure seismology alone would lead to a solid inner core, but there is abundant evidence  supporting that fact. When you combine Seismology, rare bits of geochemistry, the calculation of Earth's gravity , and perhaps the most important part, the magnetic dynamo generating our magnetic field, we see a fairly clear ( albeit incomplete) story.


What does the precessional parameter measure?

What is usually shown in cyclic plots showing precession is the precession index ($e \cdot \sin\varpi$ where $e$ is the eccentricity and $\varpi$ is the moving longitude of the perihelion). It is dimensionless ($e$ and $\sin \varpi$ being ratios).

Here is the precession index for the last 2 Myrs that I plotted using data from Laskar et al. (2004) (in the data file, first column is the age, second the eccentricty, third the obliquity and fourth the longitude of perihelion from moving equinox):

As for the range of values, by definition a $\sin$ can only take values on the range [-1,1], while the eccentricity (at least during the last 100Myrs) has values ranging from 0 to 0.067; hence a resulting precession index ranging in theory from -0.067 to 0.067.

References

Laskar, J., Robutel, P., Joutel, F., Gastineau, M., Correia, A. C. M., & Levrard, B. (2004). A long-term numerical solution for the insolation quantities of the Earth. Astronomy & Astrophysics, 428(1), 261–285.


How much time does water takes to reach to the ground?

It depends upon the hydraulic conductivity, the degree of saturation, and the depth to water table. Generally, water seeping down in the unsaturated zone moves very slowly. Assuming a typical depth to water table of 10 to 20 metres, the seepage time could be a matter of minutes in the case of coarse boulders, to months or even years if there is a lot of clay in fine sediment. Under saturated conditions, the water might move a lot faster. Other factors include the configuration of the wetting front, the unsaturated storage, temperature, and the hydraulic gradient. So basically, there is no simple answer - it's all a matter of the local hydrogeology.

There is no substitute for local measurement - water levels in an observation bore, in the case of water table conditions, or tensiometry in the case of the unsaturated zone.


Sand on the beaches of Kanyakumari, India

There are a few studies looking at different aspects of the magnificent colours observed at the Kanyakumari region. The colours, according to the research are due to the mineral content therein.

According to the article Hydrogeological Studies of the Coastal Areas of Kanyakumari to Colachel after Tsunami, South Tamil Nadu, (Perumal et al. 2010), it is common for zircon, rutile, ilmenite and garnet to be observed in the sand - this can acount for reddish hues.

In some places, monazite has been noted, also noted in radiological studies in Baseline Assessment of dose due to Natural Radionuclides in soils of coastal regions of Kanyakumari district in Tamil Nadu, India (Sarojini, 2014).

According to a Geological Survey of India (GSI) report of the region, there are also small amounts of sillimanite and leucoxene.  They also state that there is between 10-25% silica sand content.

The presence of zircons, causing some of the brilliant lustre, was confirmed by XRD analysis discussed in the article Observations on the reported incidence of micro-diamonds in the beach sands of the Kanyakumari Coast, Tamil Nadu (Dinesh et al. 2011).

Much of the beach sand sources are likely to be weathered from the surrounding gneissic (including garnetiferous gneisses) and charnockites, as described in Perumal et al. and the GSI report.  Additionally, the report Post Tsunami Heavy Mineral Distribution
Between Cuddalore to Kanyakumari Along the
Tamil Nadu Coast, India – A Review  that also suggest some offshore and alongshore sources of the heavy minerals.


Is there any experiment to prove that CO2 with the atmosphere concentration can have greenhouse effect?

Your question about water vapour is quite a common one among people learning about the greenhouse effect. Once you discover the relevant proportions of water vapour and CO2 in the atmosphere, it's perhaps natural to assume that the CO2 can't be playing a major role. In reality it doesn't work like this, for at least a couple of reasons. First, let's look at what the 98% actually means in practice.

It's not just about the concentration

The concentration of a gas in the atmosphere isn't the only thing that determines its warming potential -- otherwise nitrogen, at 78% concentration, would be the most important greenhouse gas. Each gas has a different radiation absorption spectrum, and a different warming potential. So despite its much greater prevalence in the atmosphere, water vapour only has about twice as much long-wave absorption potential as CO2.

At this point, you may be thinking ‘but twice as much is still a lot more, so the CO2 can't be significant!’. But there's another non-obvious factor here, which has to do with the difference between feedbacks and forcings.

Forcings versus feedbacks

In the climate system, CO2 concentration is a forcing, whereas the water vapour concentration is a feedback. To illustrate the difference, here's a crude analogy:

Suppose that I'm trying to lose weight, but I'm reluctant to reduce the 300 grams of delicious chocolate cake that I eat every day. Having read that the human body is around 80% water by weight, I conclude that the cake can't be a problem: after all, I drink 2 kg of water per day, so it would make more sense to reduce that! So I cut down to 1 kg of water per day and maintain my cake intake. Several weeks later, I'm surprised to find that I haven't lost any weight! What's happened? It turns out that the human body regulates its water content, so reducing my intake just reduced my output. Fat storage isn't regulated in the same way, so the cake keeps piling up.

It's a similar story with CO2 and water vapour: CO2 concentration in the atmosphere actually changes for a long time (decades to centures) when we release more gas. Water vapour is, in effect, self-regulating. If we could wave a magic wand and instantaneously remove all the water vapour from the atmosphere, here's what would happen:

(source)

Within 50 days, the water vapour is back to  within 1% of where it would have been without our intervention.

So, if the water vapour concentration isn't controlled by input, what is it controlled by? Temperature. The warmer the atmosphere is, the more water vapour it can hold. This means that when the temperature goes up due to increased CO2, the water vapour content also increases, which further intensifies the greenhouse effect. It's acting as a positive feedback.

Since you're not the first person to ask this question (by a long way), there are already some good resources online specifically addressing the different roles of water vapour and CO2 in global warming.

"Common Climate Misconceptions: The Water Vapor Feedback" is a 2008 piece in the Yale Climate Connections series saying more or less what I've said above, but in more detail and without the cake analogy.
"Water vapour: feedback or forcing?" is a great 2005 essay by Gavin Schmidt explaining the role of water vapour in climate change.
"Explaining how the water vapor greenhouse effect works" is a brief Skeptical Science piece mainly focusing on the positive feedback effect.

Laboratory measurements of CO2 absorption

You seem to be particularly interested in laboratory experiments on
carbon dioxide absorption. As an excellent starting point, I can
recommend the (currently) 26 publications in AGW Observer's list of
papers on laboratory measurements of CO2 absorption properties. If you're really keen to see experimental confirmation that CO2 can still absorb radiation even at atmospheric concentrations, you could take a look at (for example) Taylor and Yates (1957), Yates and Taylor (1960), or Streete (1968), all of which clearly demonstrate that CO2 absorption bands are present in normal atmospheric air.

As an aside: personally I find find that the numerous spectroscopic observations of the whole atmospheric column -- from satellites or ground stations -- provide a more compelling demonstration of the greenhouse effect. After all, the atmosphere isn't a homogeneous bottle of gas that can be faithfully scaled down into a lab sample. But your question and subsequent comments indicate that you're not interested in measurements of the atmospheric column itself, so here I'm just concentrating on ground-level experiments which demonstrate the long-wave absorption properties of CO2.

Answers to comments

  If there is a such positive feedback exist without other negative feed backs, the earth will get warmer without co2 contribution.

I think you might be a little confused about the definition of a feedback here. As I've tried to explain above, the term ‘feedback’ means that the water vapour content is determined by other factors within the climate system. It can amplify the effects of forcings, but it can't in itself ‘push’ the system one way or the other. So you can't have a positive feedback without some kind of forcing: the forcing is precisely the input which the feedback is ‘feeding back’ into the system, in this case via the global temperature increase.

To understand the difference, it might be helpful to think about another form of feedback familiar to a lot of people -- audio feedback through an electric guitar and amplifier system. As you can see in the linked video, there's no sound until the guitarist plays a chord. But once he does play a chord, the guitar pickup itself detects the amplified sound and feeds it back into the amplifier, creating a loop which sustains the sound indefinitely. You can think of the initial chord as analogous to the CO2 input, and the feedback loop as analogous to the water vapour effect: the audio feedback, like the water vapour feedback, doesn't do anything until it's got an initial input from some other source.

  All co2 released from fossil fuel was in the atmosphere during the dinosaurs time. If co2 release from all fossil fuel, it will restore the dinosaurs time atmosphere status. ... you can not deny that those co2 was in the atmosphere in earth history and earth animals and plants flourished

This doesn't really have much to do with your original question! If you want to ask about this, please go ahead and post a new question; StackExchange isn't a discussion site, and we try to keep each question focused on a single topic.

With this in mind, I'll just give a very brief answer here. Your formulation is a little inaccurate: the age of the dinosaurs spans at least 135 million years, there was a lot of carbon burial before it started, and all the carbon currently in the ground wasn't in the atmosphere at the same time. However, it is true that the Earth has seen higher CO2 levels than at present, and that much of that excess carbon is now locked up in fossil fuels. So what would happen if we put a lot of that carbon back in the atmosphere and tried to recreate the high-CO2 atmosphere that, say, T. rex breathed in the Late Cretaceous? Back then, the Earth was a lot warmer, with little or no ice at the poles. One of the biggest effects of re-releasing all that carbon would be the melting of our current polar ice sheets, raising sea levels by some tens of metres. The problem is not that the Earth will become completely uninhabitable by any life form whatsoever (although many current species will go extinct). The problem is that a lot of species, including Homo sapiens, are poorly prepared for a climate change of this magnitude. Ten percent of the world's human population and 8% of its urban land area is in low-elevation coastal zones, and would be completely submerged by a 10-metre sea-level rise -- which is still far less than the sea levels seen during the age of the dinosaurs.

Sea-level rise is just one effect among many, but for now I'll leave it at this since (as I mentioned above) this isn't related to your original question.

  If a person cut his water intake in half, he will get sick before he can get fatter.

This is a little peripheral to the question, I think :-). If you don't like the analogy you can ignore it: it's not essential to the explanation. However, just to reassure you: the EPA Exposure Factors Handbook (2011 edition) gives a mean value of 1,043 ml for the daily drinking water intake of an adult in the US. Thus, I don't think that restricting one's water intake to 1 kg per day, as in my thought experiment, would necessarily cause sickness.

References

Streete, J. L. (1968). Infrared measurements of atmospheric transmission at sea level. Applied optics, 7(8), 1545-1549.
Taylor, J. H., & Yates, H. W. (1957). Atmospheric transmission in the infrared. JOSA, 47(3), 223-226.
Yates, H. W., & Taylor, J. H. (1960). Infrared transmission of the atmosphere (No. NRL-5453). Naval Research Lab, Washington DC.


Does PV=nRT mean that isobars are also isotherms?

No. After a bit of mathematics, and the inclusion of water vapor, you can also get $P=\rho_d R_dT_v$, where $\rho_d$ is the dry air density and $R_d$ is the specific gas constant for dry air, and $T_v$ is the virtual temperature. So isobars are more than just isotherms- they are also dependent on density and water vapor. Check out Wikipedia's derivation for the proof that $PV=nRT$ is the same as $P=\rho RT$, and then use the fact that $\rho$ has both dry air and water vapor, to get $P=\rho_d R_dT_v$.


Why does the Earth's crust have more aluminum than magnesium while the Sun has more magnesium than aluminum?

On the earth as a whole, there is much more magnesium than aluminium.
Your question is why, specifically in the crust, there is more aluminium than magnesium.
The reason is that Mg is a compatible element whereas Al is an incompatible element. There were several questions here that addressed some aspects of this topic, for example:
What are the high field strength and large ion lithophile (HFS or HFSE & LIL or LILE) elements?
What was the likely composition of Earth's early crust (how did crustal composition evolve)?
Why silicon is abundant in earth surface?
Why do felsic materials have lower melting points than mafic?

Why is there more Al than Mg in the crust?
In earth's (upper) mantle, most Mg is inside the mineral olivine, with some in other minerals such as clinopyroxene and orthopyroxene. In contrast, most Al is in the minerals plagioclase, spinel, and garnet. There could be a tiny amount of Al in the pyroxenes as well.
When you melt the solid mantle rock that is composed of all of the minerals I listed above, some minerals melt at lower temperatures than the others. So the magma composition that is formed more closely resembles those minerals that melted.
As you can guess, the Mg-rich minerals are refractory (that is, they are harder to melt). The Al-rich minerals are usually very easy to melt. So whenever you have magma that comes from the mantle into the crust, it will have more Al than Mg. Over the billions of years of Earth's crustal evolution, quite a lot of Al (along with Na, K, Fe, Ca, and Si) accumulated in the crust, relative to the amount that was in the parental mantle.


Would hurricanes on an ocean planet continue indefinitely?

No. As it is, many hurricanes never make landfall. In an oceanic world I could see three fates happening:

Hurricanes that dissipate due to dynamical features or climatological features.
By dynamical features, I mean things like two hurricanes that shear each other out or produce an environment that can't be sustained. An example of the latter is upwelling, which generates cooler water that saps the energy from the hurricane. A climatological feature that might prevent a hurricane from developing indefinitely might be the Azores high. As it is, there are places that hurricanes don't seem to go.

Hurricanes that undergo extratropical transition.
Notice in the figure above, the hurricanes just disappear near the poles? As they come closer to the poles, the temperature difference becomes larger. Eventually they no longer look like tropical cyclones/hurricanes (little to no temperature difference), but rather look like an extratropical cyclone (see this link for some differences). This process is called Extratropical transition.

Chavas and Reed (2019)
While looking up papers for this question, I stumbled upon this paper. It implies that we would get longer lived hurricanes spreading the entire planet. I'd be a little skeptical of this result though, since it ignores the fact that the earth is heated unevenly, which drives most of the climate.

On a side note, such simulations do exist. These are called Aquaplanet simulations. Some studies I found include:

Li et al. (2011)
Merlis and Held (2019)
Chavas and Reed (2019)
Viale and Merlis (2017)

And for kicks and giggles, if you want to consider what the worst-case scenario for a hurricane could be, such a thing has been named a "Hypercane" (see here, too).


Is there a way to find the direction to land in the middle of an ocean?

Your best bet without modern tools would be a sextant and the proper maps for celestial navigation.  This is a time-tested and old method of navigation no longer in regular use, but it probably doesn't meet your "no over-technical methods" criterion as it requires a tool, maps and knowledge of its use.  If you only had knowledge of the constellations and a few stars (e.g. Polaris, the Sun) you could probably figure out what region of the globe you were on and make a best-guess as to the direction of land.

You might be able to do a similar guess with surface winds, ocean surface flow and temperature to get a rough location but if any synoptic conditions are masked by storms or local anomalies then this will likely not work.  There are some semi-presistent weather features (e.g. the Bermuda high) that you could use along with knowledge of the general circulation that could potentially help you out.  You could make similar estimates with ocean current and temperature (if you have equipment to measure this), but I think this would only provide regional benefits and may not work everywhere you could find yourself.  These would also be marred by tropical convection (e.g. in the wake of a hurricane sea surface temperatures will be cooler than normal) and other storms.


Hydro-meteorological hazards vs climate extremes

The UN International Strategy for Disaster Reduction gives a good definition of a "hydrometeorological hazard": Natural processes or phenomena of atmospheric, hydrological or oceanographic nature, which may cause the loss of life or injury, property damage, social and economic disruption or environmental degradation..

The IPCC define and "Extreme weather event" as follows: "An extreme weather event is an event that is rare at a particular place and time of year".

The debate around extremes is strongly focused on extremes which are of interest to society because of their harmful effect (extreme wind, extreme heat, extreme cold, etc), but the term itself could be interpreted as having a broader meaning. We might, for instance, experience extremes of the surface pressure difference between the Azores and Iceland (a statistic which is studied by climatologist because changes in this statistic have interesting links to weather patterns in Europe) -- but this pressure difference is not usually considered as a hazard.

An earlier answer by haresfur has given several examples of hydro-meteorological hazards which are not climate extremes. To these I would like to add:

Coastal erosion: this is a continuous process caused by tides and storms. It is hazardous for anyone living in a coastal region;
Lightning strikes: thunderstorms always pose a hazard. You could, of course, call every thunderstorm "extreme", but this is not the common usage. Thunderstorms can be common in a given region, but still be a hazard.

Hence, though the bulk of public and scientific debate occurs at the intersection of extremes and hazards, there can be hazards which are not extreme and extremes which are not hazardous.


Distance to epicenter vs distance to focus

This is a good question, but it really has a simple answer. How can you determine the depth of an object when you are not even calculating it? Triangulation uses circles, 2-D shapes, so when finding the solution to the equations of circles that solve all 3 circles, you only find X and Y. Z isn't even being solved for.

Triangulation is not precise. In practice, we end up using much more than 3 stations and statistical methods to find the precise epicenter (and other methods to find the focus).


How did these grassy hillsides in Colombia become terraced?

These are terracettes https://en.wikipedia.org/wiki/Terracette#targetText=In%20geomorphology%2C%20a%20terracette%20is,them%20to%20move%20slowly%20downhill
  These are caused by natural earth movements as the slope angle is beyond the natural resting angle of the soil. These slopes are a result of rapid erosion e.g. by rivers and glaciers.
Solifluction https://en.wikipedia.org/wiki/Solifluction is a similar process.


Seeing a varied change in brightness across the landscape during sunrise?

TL;DR: It certainly is possible from a geosynchronous orbit, an altitude of 35786 km. It is also possible from a very high altitude weather balloon.

A key issue is that the terminator is not a line. Thanks to the Earth's atmosphere, the terminator is instead a band that is about 1000 km across that gradually transitions from sunlit to dark. At most latitudes sunlight notably  starts to decrease at least 10 minutes before sunset, but one can continue with outdoor activities for a half hour or more  after sunset. (The reverse is true for sunrise.) That 40 minute period or longer time span corresponds to a very wide band. Even an SR-71 could barely have seen that ~1000 km wide band that transitioned from sunlit to dark.
In addition to barely being high enough, another issue with an SR-71 was that they moved so fast. Something that flies even higher than did an SR-71 but flies much, much slower than an SR-71 is needed. That would be a high altitude weather balloon. A high altitude weather balloon (30 km or higher) could see both the bright and bright sides of that 1000 km band, and it could see that band slowly moving.
Even higher up (much higher up), that widish band doesn't look at that wide from the perspective of a geostationary satellite. Now it does looks a bit like a line. Just as is the case with a geostationary high altitude weather balloon, a geostationary satellite would be able to see the terminator (now a line rather than a band) move over the more or less stationary Earth.


What atmospheric radiative effects, if any, do contrails cause?

We had a surprising opportunity to study this very question during the period of September 11-14, 2001, when all air traffic was grounded across the United States.

The research was inconclusive, but they found that there was a 1.8 degree celsius increase across the US during this time frame compared to the three days before and after that time frame.  However, this shift may have been coincidental.  It was found by others that this temperature shift was within the normal range for the time of year.

Ultimately, the question of whether these high-level clouds impact the weather and temperatures is still an open debate.

The source for this answer is from a Nature.com article.  However, they take their sources from the original research:

Travis, Carleton, & Lauritsen showing contrails have an effect
Hong, et al showing contrails do not have an effect


Global Gridded Daily Temperature (at 2m): difference between GEFS Reforcast and NCEP Reanalysis

The fundamental difference is that you are comparing an ensemble reforecast with a reanalysis product. The assumption here is that the reanalysis provides the best possible information based on all available measurements using state of the art modelling.

The reforecast on the other hand simulates the forecast process based on current models and all available observations, i.e. it only utilizes observations up to the forecast base time, then runs a forecast just like a forecast system does in real life. This might still be good but you are looking at forecasts with a lead time of 0 to 24 hours if you are using the first day.

Also, GEFS is an ensemble system. That means that it performs several forecasts for the same days using different starting parameters. In this way, it is possible to estimate the uncertainty of the forecast system. E.g. if for a certain day the available forecasts deviate a lot, you can assume that there is higher forecast uncertainty.

As a summary, I'd say that using reforecast data would require some more justification than using reanalysis data. Using the ensemble information may be a good reason to use GEFS reforecast but would also add another layer of complexity.

Finally, allow me some general comments:

Have you considered using data from other services, most notably ECMWF? The ERA-Interim reanalysis is quite commonly used and has very good reputation. Or, as gansub pointed out, you can consider the reanalysis by JMA.
No matter which product you are using, do not take the results as "truth". You may find that interpolating down to an individual location requires more thought than people usually expect. For example, what happens if your location is a land location but falls into a sea pixel? This would greatly affect simulated 2m temperatures and the diurnal cycle. Using a neighbouring pixel in such cases may get you better results.
Speaking of the diurnal cycle, do you really care about daily means? In this kind of studies, I have seen people distinguish between day and night-time temperatures, which appeared to me as quite crucial.


That's amethyst, a violet version of quartz

See here


This tool lets you determine daylight hours from latitude for any day of the year.

I feel like this answer should be longer, but there is not much more to say.


How does anthropogenic heating affect global warming?

A recent study by Chen et al. (2014) in the article Anthropogenic Heat Release: Estimation of Global Distribution and
Possible Climate Effect defined the heat release as you described as being Anthropogenic heat release (AHR), and has it basis as a product of economic prosperity, which leads to energy usage and excess heat produced - usually in large cities globally - this is sometimes referred to as 'waste heat'.

In their research, Chen et al  report on an earlier global estimate made by Chen and Shi, 2012:

Globally, the estimated AHR is 0.03 Wm$^{-2}$
Over land, this average becomes 0.10 Wm$^{-2}$

Although, globally, these amounts are considerably less than that from $\ce{CO2}$ emissions, they still add to the problem - especially as the rate of urbanisation, hence the use of heat generating appliances is increasing rapidly, this value will become more significant.

However on a regional scale, over large cities for example, such as Tokyo, the effects of AHR are more profound.  In and around the region around Tokyo city, the AHR can exceed 400 Wm$^{-2}$.  So what are the consequences of this flux?  Most of it causes regional effects, in particular (from Chen et al.):

Can influence urban climates and is a significant contributor to the urban heat island, which amongst other things can affect regional rain patterns.
Can affect the dynamics and thermodynamics of urban boundary layers.
Can influence the reaction rates and types of emitted aerosol and particulate species.

All of which have a compounding effect in the regional and to a lesser degree, global environment, that Chen et al. attribute to as being a cause of a 1-2K temperature rise in high altitude areas in Eurasia and North America and as a disrupting influence in global atmospheric circulation.

Edit 28/2/2016: There is an interesting blog post about a similar phenomenon: Dubai construction alters local climate

Additional references

Chen, B., and G.-Y. Shi, 2012: Estimation of the distribution
of global anthropogenic heat flux. Atmos. Oceanic
Sci. Lett., 5, 108–112.


Would epicenters in less-deep areas of ocean tend to reduce the impact of a resulting tsunami somehow (wave "breaks" before getting there?)

Tsunamis are created when large volumes of water are displaced vertically.

The predominant ways this can happen are when an earthquake of significant magnitude is created at a subduction zone - one tectonic plate subducting under another tectonic plate. During such an event, part of one plate moves downwards or upwards very quickly causing the water above it to be displaced vertically.

The other predominant way a tsunami can occur (seismically) is when an earthquake causes massive subsidence or slumping of material on the ocean floor - such as an underwater landslide. This can also create a significant vertical displacement of water. It is speculated this was the cause of the October 2018 tsunami in Palu, Indonesia.

There are meteorological causes of tsunamis but I won't address them because your question relates to seismically induced tsunamis.

The epicenter of an earthquake, whether under shallow or deep water, is largely immaterial to the creation of tsunamis. What is is critical is whether the earthquake has caused sufficient water to be displaced vertically either through sea floor movements (tectonic plates) or slumping or subsidence of sea floor material.

The difference between a quake under shallow and deep waters would be the size of the tsunami - how much water has been displaced vertically, how much energy has been imparted into the water and thus how high any wave will be and the destructive energy that it has.

Humans have tried to create tsunamis but were largely unsuccessful. During World War II, in Project Seal, New Zealand tried experimenting with explosives in what is now Shakespear Regional Park. Likewise, the US did similar experiments during nuclear weapons testing in the Pacific Ocean - Operations Crossroads and Hardtack, at Bikini Atoll. The heat from the nuclear weapons produced a lot of steam, but not significant tsunamis.


How much role does radioactivity play in making Earth geologically active

The idea that the heat of the earth is from the time of its formation dates back to the late 1800s before radioactivity was known.  Unfortunately for that theory it was shown that an initial blob of molten rock would cool to a solid chunk, radiating its heat into space, in a few tens of millions of years.
When radioactivity was discovered it was seen as a way out of the problem but the known radioactive elements were sufficiently rare in the earth's makeup that they couldn't provide enough heat.  Finally in the fifties the bulk composition  of the earth and the occurrence of radioactive isotopes were well enough known that it was shown that there is enough radioactive potassium, with a long enough half life, to provide the observed heat flux from the earth's interior.  Most of the heat is generated in the mantle, not the core since, as you point out, that is where the potassium is.  The mantle is also the layer that has convection currents in it to release that heat and drive plate tectonics.
The outer core is liquid because, at the pressure it is under,  being a liquid is the thermodynamically stable state of the heavy core minerals.  The ice under a skater's blade turns into a thin layer of water under the passing skater's pressure, lubricating the passage of the skate.  The water does not warm up much, it is still below freezing, but it is not stable as a solid under the pressure of the skate. As soon as the pressure is released the water returns to ice which is the stable state of H2O at atmospheric pressure and sub-freezing temperatures.  Similarly the outer core is liquid because that is its stable state given the pressure and temperature at that depth.
Increase the pressure more, as happens as you go deeper, and the stable state of the core material is a solid.  This explains the reason the inner core is solid.


Could Earth have had a greater axial tilt?

There is no evidence that Earth had a much greater axial tilt so long ago.  To my knowledge, the evidence for changes in the axial tilt of the Earth is based on ocean sediment cores (see http://en.wikipedia.org/wiki/James_Hays ) and ice cores ( see http://en.wikipedia.org/wiki/Milankovitch_cycles#Axial_tilt_.28obliquity.29 ).  However, these only go back 100s of thousands of years.  There is no record that I know of that could be used to assess the axial tilt of Earth 100s of millions of years ago.  However, you could speculate that after the collision that Earth had that led to our moon, the axial tilt could have been much greater as a result.  However, all records that I have seen show that the axial tilt fluctuates from 22.1 to 24.5 degrees.


Can an aurora australis be bright enough to illuminate someone's face?

If your eyes are fully adapted to the darkness you will be able to see a persons face in the light from the auroras.

By fully adapted to darkness means sitting in a totally dark room for 20+ minutes before you start looking at the night sky. The time you will need to adapt depends on your age.

Any bright light will destroy your night vision. As we get older our night vision will get poorer so young people will see better at night than older people do.


Estimated sulfur release 325 gigatonnes = 325,000 teragrams. The numbers in this diagram are in teragrams

Sulfur Cycle

so the release is $\approx 1000\times $ today's annual sulfur cycle.

I think most of the sulfur compounds would be washed into the ocean and then deposited into sediments. I can't find how much sulfur is currently in the oceans, this article says gigatons (because you can smell it). I also can't find how fast the increased sulfur would be deposited.

Another issue is that, unlike iridium, there is normally a lot of sulfur in marine deposits, so it is hard to distinguish what comes from Chicxulub.


What is the purpose of this large structure on a Japanese hillside?

The structure looks similar to this photograph of a "Japanese land retention system" mentioned in passing towards the bottom of this webpage. From the linked page:

  Land retention systems in Japan, for example, are often designed as heavy waffle grids which are molded to the topography and cover it to a uniform structural depth.

This seems to correspond roughly to the structure in the question, although the "waffle-grid structure" is only evident in some parts.
I've been unable to find any more details online about these land retention structures and their design.

As farrenthorpe writes in a comment, the three-dimensional view is probably more informative:

At first glance the siting seems strange, since there is no major settlement or road below the structure. However, it does overlook a river which, around 3 km downstream, feeds into the Tenjin water storage dam. In the current Google satellite imagery the riverbed is mostly dry and ongoing engineering work is visible in it, presumably also related to debris/sedimentation control. Similar hillside structures can also be seen on some of the slopes around the dam itself.


Yes, the age of the Earth is about 4.5 billion years (4,500 million years). Your linked articles describes well how it was formed and how we know about it. The uncertainty is less than 1% and depends partly on the radiometric dating methods and partly on the definitions. Sometimes the age is said to be 4.567 Ga, that might be a little too exact number to claim, but at least it's easy to remember.

I haven't heard any different age constraints that are scientifically founded, but before we had access to the methods and data we have today, there was a broader range of estimates.

Early estimates were based on the supposed increased salinity of the oceans, but those estimates fail to recognize that salt is also removed from the seawater in subduction zones and to form evaporites.

Noteworthy is Lord Kelvin's very sensible estimate of 20–40 million years, published first in 1863. The estimate was based on the heat lost since formation and Earth's capacity to withhold its energy. Unfortunately, Lord Kelvin worked too early to know that $E=mc^2$, so energy is also generated within Earth and that is the main source of heat. He also didn't understand the Sun's source of energy and convection and therefore miscalculated the solar age constraint and Earth's heat flux.

Radioactive decay is not only the source of heat but also the process we use to measure the age by radiometric methods. These methods became known decades later and quickly provided age constraints sin the right magnitude.

Earth scientists have assumed the deep time age of Earth since the antiques. It must have been frustrating for the early geologists to not be able to put a number of the Earth's age. As a rudiment of that time, we still use their relative terminology to describe the development.

Our present estimate is based on a range of agreeing models and data. The Earth science community has, in general, moved on to new and more challenging questions.


Is there evidence to suggest that the release of methane clathrates in permafrost regions will impact climate change?

Your first two links don't seem to mention clathrates.

Much ado about methane says:

  What methane are we talking about?
  The largest methane pools that people are talking about are in sediments of the ocean, frozen into hydrate or clathrate deposits (Archer, 2007). The total amount of methane as ocean hydrates is poorly constrained but could rival the rest of the fossil fuels combined. Most of this is unattractive to extract for fuel, and mostly so deep in the sediment column that it would take thousands of years for anthropogenic warming to reach them. The Arctic is special in that the water column is colder than the global average, and so hydrate can be found as shallow as 200 meters water depth.
  On land, there is lots of methane in the thawing Arctic, exploding lakes and what not. This methane is probably produced by decomposition of thawing organic matter. Methane could only freeze into hydrate at depths below a few hundred meters in the soil, and then only at “lithostatic pressure” rather than “hydrostatic”, meaning that the hydrate would have to be sealed from the atmosphere by some impermeable layer.
  ...
  The possibility of a catastrophic release is of course what gives methane its power over the imagination (of journalists in particular it seems). A submarine landslide might release a Gigaton of carbon as methane (Archer, 2007), but the radiative effect of that would be small, about equal in magnitude (but opposite in sign) to the radiative forcing from a volcanic eruption. Detectable perhaps but probably not the end of humankind as a species.


Color of ocean waters and Ekman pumping - what is the connection?

The relationship of the observed "aquamarine color" near the coast and the Ekman pumping in the open ocean, while possible is rather unlikely. Ekman pumping is confined to the areas affected by the cyclonic wind stress curl and by definition it is mostly effective in the open ocean, where there is no bottom boundary effect. The color of the coastal waters is likely more affected by the upwelling-favorable wind creating upwelling conditions that provide nutrients to the coastal areas. The fact that the color is affected by the sea-breeze is even more justification for the upwelling mechanism. While transport of nutrient-rich waters to the coastal areas is not uncommon, the time scales associated with primary production especially in coastal areas are quite fast and tend to use the open-ocean nutrients in short time scales.

Phytoplankton changes especially on the order of hours are more likely associated with purely coastal processes. While there might be an input of open-ocean nutrients to the coastal areas, the coastal primary production tends to differ from open-ocean communities and tend to respond rapidly to extra nutrients.

The aquamarine color could be the result of many coastal processes. Without knowing the area, I don't feel qualified to make a strong case about the causes. Reasons for the color could include 1) vertical phytoplankton migrations that settle to the bottom/lower water column when the breeze comes up; 2) the sea breeze resulting on a local near-shore downwelling; 3) a breakdown of the stratification by the breeze that mixes down the surface layers; 4) regional features (e.g., sea level pressure gradient) that become active when the breeze is occurring. Too many unknowns for me. It would be good to know the extent and duration of the "aquamarine color" patch, the width and slope of the continental shelf in the area and the ind and stratification conditions in the near-shore and coastal areas.


Does hydroxyl radical chemistry in air quality models create numerical stability problems?

The hydroxyl radical chemistry is not modeled explicitly in air quality models, so numerical stability is not an issue.  Instead, OH is held in pseudo-steady-state.  For instance, see CMAQ's documentation which states:

  In CMAQ's gas phase, OH is assumed to be in pseudo-steady state, and it is not a transported species.  This is because hydroxyl radical reactions tend to be catalytic (e.g., consumption and production). In the aqueous phase chemistry, OH is absorbed by cloud water and in an open cloud model (i.e., the design approach currently employed), absorbed species (e.g., OH) would be replenished via gas-to-cloud partitioning. However, due to operator splitting, aqueous and gas-phase chemistry are not solved simultaneously. To account for this and other uncertainties in predicted OH aqueous phase concentrations (e.g., neglect of production reactions (H2O2 + hv -> 2 OH) not currently implemented in aqchem), a steady-state assumption for OH is adopted in the aqueous chemistry routine.

Typically, if you are trying to model something like the hydroxyl radical, you would use a box-model like MECCA, not a chemical transport model.


Whitecapping refers to the steepness-induced wave dissipation in deep water during which some air is entrained into the near-surface water, forming an emulsion of water and air bubbles (foam) that appears white. It occurs when the velocity of individual water particles near the wave crest exceed the phase speed of the wave, causing the front face of the wave to become too steep and "break". Steeper and more vigorous breakers are more efficient at entraining air bubbles into the water column, and they generate more foam.
Whitecapping is an essential process for air-sea gas exchange.

In the wave modeling community, because current spectral wave prediction models do not resolve air entrainment by the breaking waves, we use the term "whitecapping" to describe all steepness-induced deep-water wave dissipation. For example, see Hasselmann (1974).

Waves also break due to shoaling as they enter shallow water, and these are usually referred to as plunging breakers. While plunging breakers without doubt generate a lot of foam, we don't use the term whitecapping to describe them. Thus, whitecapping is a specific kind of wave breaking, as described in the first paragraph.

See a comprehensive review by Cavaleri et al. (2007) for a description of all the processes represented by current wave models.