What is the meaning of integral of negative magnetic field (nT) over time?

Disturbance storm time index is a measure of the weakened horizontal component of Earth magnetic field during great magnetic disturbances. The depression is often flanked by peaks, that initiates and ends the storm. Dst is published by Kyoto University and more information about the methods and references are available on the web page.

  The Dst index represents the axially symmetric disturbance magnetic field at the dipole equator on the Earth's surface. Major disturbances in Dst are negative, namely decreases in the geomagnetic field. These field decreases are produced mainly by the equatorial current system in the magnetosphere, usually referred to as the ring current. The neutral sheet current flowing across the magnetospheric tail makes a small contribution to the field decreases near the Earth. Positive variations in Dst are mostly caused by the compression of the magnetosphere from solar wind pressure increases.

Sugiura and Kamei, IAGA Bulletin No 40 (1991)

Measures are presented as the deviation from the average magnetic field strength, measured in the SI unit Tesla $T$ at time $t$. In this context, the magnetic field is very weak, so the nano prefix $n$ is usually used. Magnetic field strength can be derived from weight (in $kg$), electric charge (in Coulomb $C$) and time in second ($s$) as:

$T =\frac{kg}{C \times s}$

if you integrate with time (in seconds, $s$) you'll get for each unit:

$T \times s =\frac{kg}{C}$.

The relation of electric charge and weight is used as a measure of Radiation exposure, often given in röntgen ($R$) and related as:

$1 \frac{C}{kg} = 3876 R$

Technically, your integral will, therefore, be a measure of increased radiation exposure, kinetic energy released per unit mass, for the time you integrate over. You could convert it to röntgen ($2.58×10^{−4} C/kg = R$) but note that the calculated product describes the deviation, not the absolute ionization.


Current temperature increase VS decrease during the little ice age

To be sure about why it appears to be centered around -0.2°C, you'd have to go to the original source of the graph.  However, as an educated guess, I would imagine that they are showing the anomaly compared to some recent period, such as 1961-1990 or 1971-2000, as is commonly done.  From your Wikimedia Commons link, this figure appears to be original work by a Wikipedia author.  The link does not appear to state this, so this is rather sloppy and perhaps illustrates why it's preferable to obtain information from peer reviewed sources.

If the temperature increase stays at +0.4°C, it is not catastrophic.  However, considering the greenhouse gases (GHG) we have already pumped into the atmosphere, temperature increase will not stay at +0.4°C.  With currently projected increases in GHG emissions, the global average temperature increase may range from anything between +1.5°C and +6.5°C, with some regions exhibiting far larger temperature increases than that.  At such scales, the entire climate system might enter a different state, which means many regions will have climates very unlike before.  And then I'm not even mentioning the problems associated with sea level rise yet.


It's hard to visualize exactly what you saw, but typically in convective clouds, there is such significant motion that oftentimes very chaotic and varying cloud shapes will develop as a result, and they may move quite quickly due to the strong winds.  It appears the term pannus may be used for these, though I'm more familiar with calling them scud.  You mentioned rain, it's northern hemisphere summer, so these cumulus-convection byproducts sounds quite likely.

Around other storm chasers/meteorologists, I've also heard these types of clouds called debris clouds... which is a rather apropos description given that such clouds are often leftovers from earlier storm evolution (perhaps even remnants of old wall clouds if in a situation with supercells)... but using that term might bring confusion to others because tornado debris can also be called a debris cloud.  This page appears to exemplify the confusion, as the picture appears to include remnant clouds from earlier storms in the foreground while the description gives the tornadic definition.  So we probably should avoid this term.

There's no bad gas in thunderstorms... what you see in meteorological clouds is liquid or ice water (all clouds form around tiny bits of dust and such, but this wouldn't affect appearance).  Occasionally smoke or such may be ingested in a cloud, but even in situations where large fires and volcanic eruptions produce clouds, the forced moist updraft region will often look quite similar to a typical cumulus cloud.


Yes. The moon is lit by the sun, so as its position relative to the sun changes, so does the angle from which it is lit.

I recommend reading the Wikipedia page on lunar phase for a good overview, some data, and some good references. This diagram from that page more or less sums it up — the bottom row shows how the moon looks from the earth over the course of a lunar month:

Image is CC-BY-SA by Wikipedia user Orion 8.

The angle of the shadow depends on the time of the observation, and many lunar calendars seem to rotate the lunar images (as above). But this one gives a hint to the shifting relative sun position:

Image is of unknown origin, found here. Unclear rights; fair use.


Centripetal Force Perfect Ball and Water

In short, weird things happen when you combine things that don't combine in nature:

the Earth as a perfect sphere
the Earth spinning on an axis

Einstein's equivalence principle tells us that accelerations are all the same, no matter what's causing them. So you just add the acceleration vectors up.

The (real) Earth has an equatorial bulge because a stable surface can only exist where those vectors sum to zero:

gravity
residual ("centrifugal") acceleration from the Earth's rotation
the ground holding you up

This is called an equipotential surface and because of the centrifugal acceleration, on a spinning Earth this surface is an ellipsoid (well, mostly; there are small adjustments due to mass distribution).

The constraint of having a perfect sphere means that the materials making up the Earth your fictional planet are strong enough to keep it from ballooning out and filling an equipotential surface.

So if you make your fictional planet a perfect sphere, what you're really doing is changing where #3 happens but leaving #1 and #2 the same.

In other words, you're creating a 26 km deep valley encircling the globe.

Water runs downhill.

So eventually, all of the water will flow down into the giant equatorial valley...


Glossary of oil and gas industry geophysical terms

Sheriff's Encyclopedic Dictionary is the closest thing to a canonical text, but the Schlumberger glossary is more up to date.

Sheriff is a scientific text, whereas the Schlumberger glossary is a little more generally accessible, but neither is comprehensive. Sheriff is especially poor on recent advances. On the plus side, you can edit it, if you're an SEG member.

After those two, Wikipedia is probably your next best bet.


Greenhouse gas emissions from wildfires in California

The California Air Resources board posted this PDF that includes emission estimates up to 2017, which were 37.1 million metric tons. If anyone is interested in related info, the search phrase I used was, "CO2 estimates for california wildfires".


What, exactly, is angle of repose, and where is it in this image?

Geological materials such as sediments are never totally homogeneous. There will always be softer and harder regions within sedimentary deposits.

The fact that erosion channels have been created is due to the force/energy of the water creating the channels, the extent of the force the water had when it created the channels, the softness of the material being gouged out and the hardness and cohesion of the material left behind.

The angle of the walls of the channels is not sustainable and over time the walls will slump (fail) to the lower angle of repose you see for the overall deposit. When this occurs the floors of the channels will be filled with the slump material.

In the meantime, when more rain falls, the runoff will naturally flow in the extant channels - the water taking the path of least resistance. The water will flush out the loose slump material and if the force of the water is great enough it may also widened the channel and eventually cause more material to slump into the channel.

A material's angle of repose is a function of its cohesion and it is the overall/average angle the material lies at over a long period of time.


Coral growth keeping up with sea level rise?

I have worked as a climate-change specialist in many countries including those with coral atolls, such as the Maldives, Solomon Islands and Samoa. I have analysed, at first hand, both the the tide-gauge and satellite-based rates of sea level rise. Notwithstanding the non-scientific writings of that well-known journalist, Andrew Bolt, the demonstrable truth is that ocean acidification is real and unstopable for the foreseeable future. The sea surface is warming faster than expected a decade ago, and the rate of sea level rise is accelerating. In the southwest Pacific, which is particularly prone to El Nino intensification, these affects are even more alarming.

I point out that Bolt has zero scientific credentials, has never done any climate research, and is only able to make a living as a climate-skeptic writer because many Australians are, by nature, predisposed to enjoy 'contrary' arguments, irrespective of the science.

Much research has gone into coral growth over the last decade, particularly in peri-Australian waters. Current findings are that, under optimum conditions, the fastest growing corals can indeed grow fast enough to keep up with the current rates of sea level rise. However, this cannot continue indefinitely. The reef is a total ecosystem, of fast and slow growing corals, bryozoa, etc., which has an aggregate rate of growth of less than the rise of sea level. Fast growing pioneering corals eventually collapse if left to continue growing ahead of the rest of the biome. Note also the phrase "under optimum conditions". As Jan Doggen rightly points out, sea-surface warming beyond the optimum thermo-tolerance, acidification, and water pollution are all serious stress factors. Between them one can say that, apart from deep-water corals, there is hardly a coral reef on the planet that isn't  suffering from sub-optimal growth conditions.

There is another somewhat unexpected threat to corals: ordinary sun-cream from holidaymakers swimming near reefs. The common sun-cream component of oxy-benzone (present in most sun-creams) is toxic to corals at only about 60 parts per trillion. Globally, an estimated 10,000 tonnes of sun-screen ends up in the oceans, near corals, every year. This has a noticeable negative impact on the reef.

Taken altogether, this quadruple whammy bodes ill for the world's coral reefs. When the reefs die, and sea level rises there will be nothing to stop sub-tropical waves eroding the very land that some Pacific Islanders live on. Even islands with higher elevations still have fringing reefs. They are all in trouble, because sea level rise and higher erosion rates will force a retreat from the coast (hopefully planned), with massive social, environmental and economic disruption. So yes, they are absolutely justified in getting agitated about reef degradation!


This is adiabatic compression of descending air. The air warms and clouds dissolve. The air is blown by a wind that's roughly perpendicular to the ridge, causing it to rise, cool and eventually condense on the windward side and sink and warm on the leeward.


Part 1, see Neos answer.  Earth will lose its heat no matter what we do, and our extraction of geothermal energy is insignificant (Wikipedia quotes a BP figure of 11.4 GW electrical, 28 GW heating).

To answer part 2 of your question: if the Earth's core loses its heat, this will not have a major direct impact on climate.  Internal heat generation is estimated by Davies and Davies (2010) to be roughly 47 TW.  With a surface area of 5.1 × 1014 m2, this translates to roughly 0.1 W/m2.  This can be compared to the other flows in the climate system, illustrated by Trenberth and Fasullo, 2012:

—Trenberth, Kevin E., and John T. Fasullo. "Tracking Earth’s energy: From El Niño to global warming." Surveys in geophysics 33, no. 3-4 (2012): 413-426.  Weblink

So, from a climate perspective, internal heat generation is not important.  See also this post on skepticalscience.

However, we might lose our atmosphere, which would have inconvenient consequences.  An ice age would be the least of our worries.  A subsequent question would be: (How long) would Earth's atmosphere last without a global magnetic field?  That is a different question and I'm not sure if we really know the answer.


Why is the zonal component of flow in the ocean much larger than the meridional component

It is more of a consistency argument: if a constant-depth ocean with much less relative vorticity than planetary vorticity is to stay that way, the flow must be zonal.

If there were significant meridional velocities, they would cause significant meridional displacements of water masses, which would then, by conservation of angular momentum, no longer have small relative vorticity. (Same angular momentum and same depth means same absolute vorticity.  Different planetary vorticity then means different [in the opposite direction] relative vorticity. If planetary vorticity was zero before the displacement, it isn't anymore afterward.)


There is a nice tracker for global earthquake activity at https://www.volcanodiscovery.com/earthquakes/global-seismic-activity-level.html, although it doesn't conveniently allow you to look at regional statistics, as opposed to global or national records.
At a global level there doesn't seem to be any particular increase in events , although in a quasi random series clustering in time and space isn't unexpected.
The perception that there might be an increase is probably a reflection of human and media behaviour; when one event occurs it heightens our interest and the likelihood of noticing other events. The media are far more likely to report a small earthquake occurring in the immediate aftermath of a large earthquake elsewhere in the world, than they would have if it had occurred in isolation.


How many joules are required to mine a unit of coal?

The efficiency of coal as a source of electricity is very low: typically of the order of 30%. So losses are of the order of 70%. But losses due to energy expended in the extraction of the coal itself only form a very small proportion of this.

Estimates for extractive losses tend to be of the order of 0.5-5%. That's a huge relative range, because the energy density of different types of coal (J/kg) can vary by a factor of 5; the coal could come from a deep mine or an open-cast; and the amount and kind of mechanisation varies hugely.

But these huge relative variations are completely swamped in absolute terms by the other losses, which are at the very best 20%, and can be 65% or so. Which is why there's not a huge amount of literature on the energy inputs to coal extraction: it's such a small part of total losses, that it gets lost in the rounding.

In the British residential electricity supply, there's about 7% losses from local distribution (UK figure), 2-3% from transmission grid, and about 60% losses at the plant itself, in the form of heat (NB efficiencies here are multiplicative, rather than additive). The British average for 2013 was 64.2% losses in plant - see DUKES 2014 table 5.9

CHP plants mitigate this by capturing a large share of the heat, for distribution in local heat grids. But they still have losses of 5-25% at the plant itself, and then further losses in the heat and electricity distribution system. Call it 20% losses in the best case. Denmark has a lot of high-efficiency coal plants and CHP, but still only managed 55% efficiency, so 45% losses (Danish Electricity Supply '08 Statistical Survey, Table 10).


Causes and concentration of red rain of Kerala

Despite the obvious red colour Trentepohlia annulata and numerous related species are blue-green algae. The red colouring comes from beta caroteine and related natural pigments. There are very many such common pigments in nature, comprising scores if not hundreds of compounds, ranging in colour from yellow through orange, red and purple, eg. from lichens on wood bark, carrots, saffron, beetroot, and certain bird feathers/beaks - to name but a few sources. The red colourant masks the natural greenish hue of the original organism. It is a strong colouring compound which is why beta-caroteine and its derivatives are sometimes used in food colouring.

As to the concentration of algal spores, this is difficult to determine because the colour intensity is a function of the pH, exact chemical species of pigment, biological viability of the spores, and presence/absence of co-variable interacting ions in the water. As a very rough guide I would estimate that the concentration of pigment (not the concentration of spores) is likely to be in the order of 20 to 200 mg/l. For a bit of fun, you could get some beta-carotein-based food colourant and experiment on concentration and colour vs. pH.

Trentepohlia annulata and related algal species are pretty much ubiquitous in wet tropical and subtropical environments, but they don't like cold weather. The red colour in your photograph is extraordinary and very unusual. I would assume that conditions of nutrient availability, pH and temperature would have to be 'just right'.

My last comment is pure conjecture on my part - and I may be way off beam here - but maybe the intense red colour could be brought on by the physics of raindrop formation. If very moist warm air, rich in T.a algal cells was rapidly lofted in a tropical convection cell, the sudden cooling could kill off the algal cells, thereby rupturing the cell membranes, and triggering catastrophic release into solution of carotein-related pigment into resulting raindrops, which would normally pass unnoticed. Further concentration could occur by evaporative reduction of raindrop volume, especially if most of the rainfall dissipated into the atmosphere as so-called 'occult rainfall'.


Sources of $\ce{CO_2}$ during Carboniferous period

The terrestrial vegetation makes ca. 500 PgC (i. e. $500 \times 10^{15}$ grams of Carbon) which is rather small compared to the carbon stored in the ocean of ca. 37 000 PgC, see Fig. 6.1 in Ciais et al. 2013 1.
Even if we assume that the fossil fuels reserves are the remainders of the Carboniferous period, they only add up to no more than ca. 2 000 PgC.

The terrestrial biosphere only makes use of a very small portion of the total available carbon.

1 Ciais, P., C. Sabine, G. Bala, L. Bopp, V. Brovkin, J. Canadell, A. Chhabra, R. DeFries, J. Galloway, M. Heimann, C. Jones, C. Le Quéré, R.B. Myneni, S. Piao and P. Thornton, 2013. Carbon and Other Biogeochemical Cycles. In T. F. Stocker et al. (Eds): Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.


Lack of annual slash-and-burn in North America?

Slash and burn has been used in North America and still is at times.  I see regular field burning near me where fields are particularly rocky and tilling if impractical for the crops grown.  It also occurs when there is intrusions of some noxious weeds that are controllable through fire as effectively and much cheaper than chemical controls.

In general, I would consider slash and burn in disfavor because of it consumptive nature.  The practice does provide some otherwise missing nutrients, but it consumes large quantities of biomass while doing so.  More favored in many regions it to use that biomass to supplement the soil by tilling it in and allowing it to aerate the soil while slowly breaking down and augmenting the soil.  Between being fortunate enough to have good soil to begin with, or the ability to augment with either natural or chemical supplements, many North American farms do not need the quick fix burning can supply so opt for the slower, longer term solution of turning in the organic materials.


How to measure the cycles of earth moving/rotation?

In theory, if the Earth was a solid object, the Chandler wobble would be easy to understand. It's simply a result of the polhode rolling without slipping on the herpolhode lying in the invariable plane. In other words, $\mathrm I \dot \omega + \omega \times (\mathrm I \omega) = 0$, where $\mathrm I$ is the Earth's inertia tensor and $\omega$ is the Earth's angular velocity. The Chandler wobble is simply the consequence of the Earth not having a spherical mass distribution and the Earth not having it's angular momentum and angular velocity coaligned.

In practice, the Earth is not a solid object. The theory behind the Earth's orientation is rather (putting it mildly) complex. The best model involves over a thousand parameters. Unfortunately, this best model of the Earth's precession, nutation, and rotation does not explain the Earth's orientation. The Chandler wobble, along with a number of lesser phenomena, is an after-the-fact discrepancy between the very best analytic model and the very best observational results.

Knowing the Earth's orientation is extremely important to some sciences, high resolution astronomy in particular. The US Naval Observatory (USNO) publishes its estimates of the deviation of the Earth's true orientation versus that of the best analytic models on a daily basis. The USNO is a key member of the International Earth Rotation and Reference Systems (IERS, for short, and yes, the acronym doesn't work. It used to work.)


At what depth does the underground begin to warm up?

Your question has an incorrect assumption built in.  Near surface ground water temperatures are not generally colder, but rather reflect the average annual temperature. This will be colder than surface temps in summer, but warmer in winter.  There is an an additional effect if your rainfall isn't evenly distributed over the course of the year, as percolating rainfall will be initially warmed by warm soil temps in summer.  As an example, in central Alberta shallow well water temps run about 10 C, while our average temp for the year is around 4-5 C

Start here: https://www.builditsolar.com/Projects/Cooling/EarthTemperatures.htm

A graph on that page shows how soil temps vary with depth depending on seasonal variation, and moisture levels.  Ball park:  30 feet gets out out of the seasonal variation, but 12 feet eliminates about 2/3 of the annual variation.

If your climate is cold enough in winter, it may be worth your while to store coolth in the form of brine.  In effect build a well insulated building with insulated foundation with what amounts to a swimming pool in it filled with either salt water brine, or calcium chloride brine.  Have a few thousand feet of 1/2" plastic pipe (drip irrigation pipe is cheap)  both outside and in the pool, and circulate antifreeze through the pipe when winter temps are below the brine temp.  In the summer, a secondary loop circulates between the pool and the heat exchangers for the house.

If you are in a desert climate, you may be able to do something similar on a smaller scale.  Under a calm clear sky, you can often get frost on the side of an insulator facing the dark sky at night.  Modifying this idea, create a large bottom insulated surface coated with a good IR emitter (Titanium dioxide white is one such.) , and run shallow water over it.  If you can routinely get 30 C colder than day time air temps, then you only have to store a few days worth of coolth instead of a years worth.

You can make the system above colder by pre-chilling the water with an evaporative cooler

Edit:  One source claims 1 degree F per 30 feet starting at around 100 feet.  Temperatures above this
however are highly variable from water movement.


Is there a simple temperature prediction model?

Simple? Depends upon the level of accuracy you are looking for. Insolation alone is a rough indicator of sea surface temperatures.

image from http://www.ospo.noaa.gov/Products/ocean/sst/contour/

In more detail SSTs around the globe are significantly influenced by oceanic currents which, in turn, are very strongly influenced by the distribution of continents.


Dry atmospheric temperature profile (dry adiabatic vs. isothermal)

The two articles you found are spot-on. An isothermal atmosphere is indeed the condition that maximizes entropy for a given amount of energy. Yet a positive lapse rate is almost always observed. Temperature typically decreases with increasing altitude. The key to resolving this apparent paradox is how heat flows into and through the Earth's atmosphere. The Earth's atmosphere is a system that is very far from equilibrium.

If the atmosphere isn't in that maximum entropy state (and it never is, at least not from very bottom to very top), heat transfer will set up to put move it toward that state. Very key: That entropy-driven heat transfer rate is rather low. If other heat transfer processes are in play (and they always are), it is very easy to overwhelm that low entropy-driven heat transfer that would nominally equalize the temperature. The Earth's troposphere is heated from below and cooled from above. This alone overwhelms the entropy-driven heat transfer, and by multiple orders of magnitude.

The other factor is how heat flows through the atmosphere. The presence of greenhouse gases in the atmosphere set up the conditions that make a positive lapse rate possible. By way of analogy, imagine a perfect blackbody heat source that generates heat at a rate $Q$ and has a surface area A. If that heat source radiates to the dark sky, the equilibrium temperature will be given by the Stefan-Boltzmann law, $T_\text{top} = (Q/(\sigma A))^{1/4}$. (Note: I'm assuming that $Q$ is much, much greater than the tiny amount of heat coming in from the cosmic microwave background.) If you put a perfect blackbody blanket atop that heat source, the blanket will radiate at a rate $Q$ outward and inward. The heat source will receive heat from above and below, making the equilibrium temperature of the heat source with one blanket equal to $(2Q/(\sigma A))^{1/4}$, or $2^{1/4} T_\text{top}$. Yet another blanket makes the thermal equilibrium equal to $3^{1/4} T_\text{top}$, and so on.

The atmosphere with its greenhouse gases that are optically thick in the thermal infrared acts as a bunch of blankets. Obviously not perfect blackbody blankets, but blankets nonetheless. This is what favors the development of a positive lapse rate.

This favoring isn't universal. There are times when weather creates conditions where the lapse rate is negative, that is, temperature increases with altitude. This turns out to be a very stable condition (the name for this is a "very stable atmosphere"). This negative lapse rate precludes rising and falling parcels of air. With calm air as well, the only thing that can transfer heat is diffusion, which is a very slow process in the atmosphere.


What are these lines that I frequently see on doppler radar?

If they propagate outward from thunderstorms, they are outflow boundaries. Cold air flows down from the thunderstorm with precipitation and spreads outward upon hitting the ground. This air moves ahead of the storm and forces warmer air upward, suspending clouds and other particles. That's what is visible on radar.
More: https://en.wikipedia.org/wiki/Outflow_boundary


...the submerging plate is always drawn as deep (seemingly tens of km) into molten rock...

It's actually hundreds of kilometres, not tens of them. But let me correct a common misconception:

The mantle is solid rock. It is not molten rock.

So subduction leads solid rock into more solid rock.

  the surrounding medium is hot enough to melt rock

The surrounding medium is hot enough to melt rock only under very special circumstances, the two most common being:

If the rock gains water somehow (yes, water under pressure helps rock to melt), or
If even hotter rock from down below rises up and decompresses.

  Why are so many textbooks drawing it submerged and unmelted to such depths?

Because it doesn't melt. The subducting plate goes down faster than it heats up. Therefore, pressure increases faster then temperature. This does not allow melting of the subducting slab.

What does happen? The slab loses water. Remember - this was oceanic crust and it's wet. On moderate heating, the water from hydrous minerals (serpentine etc) is lost to the mantle rocks above it. Because the mantle rocks above the slab are hot, the addition of water causes them to melt. We see this all the time in the form of arc volcanoes. The Pacific "rim of fire" is the most famous example of this process.

I would say that some very limited amount of melting may actually happen, but in terms of volume % of the entire slab it's likely to be negligible. The contribution of this melting to global volcanism is also likely to be negligible.


How to classify the ENSO phase of a year?

First, based on the ONI, there are El Niño and La Niña periods, not necessarily years. For example, 2016 was El Niño during the first half and La Niña during the second half. On the flip side, From summer 1998 to early 2001 was one continuous La Niña period.

Second, The The wording that the NOAA gives for official classification of El Niño and La Niña periods is a bit misleading. El Niño periods are designated as such when there are 5 consecutive three-month-running means of sea surface temperatures that are 0.5 degrees C above the 30 year mean. For example, take a look at NOAA's ONI data here: https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php
in 2016 there was an La Niña event that lasted from July to January because there were 5 three-month-running means in a row that were 0.5 degrees C below the 30 year mean. However, this only encompasses three "season", summer, fall, and winter.

Third, to answer your question, El Niño/La Niña classification is not bound by a calendar year, so going forwards and backwards until you hit a three-month-running mean that is less than the 0.5 threshold. The NOAA has already down the work for you, and even color coded it for you at the link above. Hope this helps.


The main resistance that winds have to their movements comes from the topography and surface obstacles. Therefore, as a general rule the closer to the surface the less wind you will find. But I guess you are interested in the winds in areas clear of surface obstacles, otherwise the answer would a be a cave or a dense forest somewhere.

To figure out what is the calmest place on Earth wind-wise, we can use one of the global datasets that NASA put together (initially to help with solar and wind energy planning). One of them is a 10-year average (July 1983 - June 1993) of wind speed at 50 m above surface, ignoring the effect of trees and other non-topographic obstacles at a resolution of one degree (roughly 111 km or less).
I just loaded that dataset and searched for the minimum (and maximum) values, this is how it looks:

The minimum is not actually in Antarctica as your research suggested, but in the Amazon at longitude 68° west and latitude 0° (that's Brazil near the border with Colombia), with a mean wind speed of 1.55 m/s (5.6 km/h).

This is an enlarged version of the most relevant area overlaid with a world map for easier interpretation:

In line to what was stated at the beginning, the maximum happens in an area were the lack of landmasses allow it to blow unimpeded around the world. And it happens at 60° W -52° S, reaching a mean wind speed of 12.62 m/s (45 km/h).

Note that this analysis is valid for broad areas. And of course individual weather stations at punctual locations can give different values. As for Antarctica, the winds there are mainly catabatic, therefore at the top of antarctic domes the average wind speed are very low. For example the average at Dome C is 10.1 km/h and 9.4 km/h at Dome F. However, those values are still bigger than what NASA's models suggest for the Amazonas.

I think the model I used here is reliable. As an exercise, you can see all the images that show up in a Google search for "global mean wind speed" and you see that most images show a similar pattern, where Antarctica doesn't seem to contain the calmest place.

The model used to produce these datasets is a reanalysis, it means it takes all the weather data of the past (weather stations and satellite data) and attempts to reconstruct how exactly was the weather over the whole word. A similar kind of model takes only past weather data and attempts to predict how will be the weather over the whole world. That's a much more difficult problem, prone to bigger errors but that's actually what all the weather forecast we see on TV are based upon. One of the best global forecast models is called GFS (Global Forecast System) that is produced by NOAA's Environmental Modeling Center.

To have a sense of how winds vary in different locations and altitudes you can explore the GFS  data using Cameron Beccario's amazing vizualization tool. There you can see the predicted global wind patterns all the way from the surface to more than 26 km of altitude (here you can find a table with referential equivalences between pressure levels in hPa and altitudes). Despite those are not multi-year averages, they are still very informative. Muze, the author of the question, pieced together a beautiful animated gif that show how the above mentioned visualization looks like for the elevation range of the jet streams at about 10 km of altitude (250 hPa):

Finally, I have to note that I've interpreted "calmest" as the minimum mean wind speed. However, it would be sensible also to consider it as the place with the lowest maximum wind speed or some other metric, that would perhaps change the picture described above. And maybe using that metric one of the Antarctic domes could be the "calmest" place. But I won't extend the answer further with any possible interpretation for "calmest".


To delineate the drainage basin for a lake, would the pour point be the inlet or the outlet?

I think there are a few things to consider. First, a drainage basin is defined as the area upstream of the point to which all precipitation converges. Flow does not converge at the outlet - flow converges at the lake. Outlets don't contain any additional information of the upstream area draining into the lake. This implies that to find the area draining into a lake, you would necessarily have to proceed beginning from each and every inlet.

Here's another way to see this. Approximately 20% of all land drains to lakes with no outlets. These are referred to as endorheic lakes or endorheic basins. Even though there is no outlet, there is absolutely still a definable drainage basin area.


Is the Younger Dryas associated with an extinction event?

Some authors thinks that the extinction of the Pleistocene megafauna (large mammals such as mammoths, etc.) was contemporaneous with the Younger Dryas (Firestone et al. 2007; Faith & Surovell 2009), while some thinks that it predates it by a couple thousand years (Gill et al. 2009).

Whether or not it was contemporaneous with the Younger Dryas, it constitutes a rather modest extinction event compared to the Big Five (i. e. the five bigger mass extinctions of the Phanerozoic: End Ordovician, Late Devonian, Permian/Triassic boundary, Triassic/Jurassic boundary and Cretaceous/Paleogene boundary, see this previous answer of mine for more details on that), with nonetheless a noteworthy impact (e. g. Johnson 2009) on the remaining ecosystem. The current/future mass extinction is however often considered to be at a comparable scale with these previous five (see for instance Barnovsky et al. 2011), but climate change is not the only one to blame: active destruction of ecosystems, mainly through anthropization, is one major factor as well.

References:
Barnovsky et al., 2011. Has the Earth’s sixth mass extinction
already arrived? Nature, 471: 51-57.
Faith & Surovell, 2009. Synchronous extinction of North America’s
Pleistocene mammals. PNAS, 106(49): 20641-20645.
Firestone et al., 2007. Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling. PNAS, 104(41): 16016-16021.
Gill et al., 2009. Pleistocene Megafaunal Collapse, Novel Plant Communities, and Enhanced Fire Regimes in North America. Science, 326: 1100-1104.
Johnson, 2009. Ecological consequences of Late Quaternary extinctions of megafauna Proc. Roy. Soc. B, 276 (1667): 2509-2519.


Upon breaking apart andesite, what do you get?

By definition andesite is mainly plagioclase (mostly variety andesine),and pyroxene with either quartz or olivine (not both), and minor amounts of magnetite, ilmenite, zircon, apatite, possibly biotite mica, and maybe a few traces of rarer minerals. The pyroxene is probably a mixture of orthopyroxene and augite. In addition to plagioclase there may be small quantities of other, more alkaline feldspars.

Andesite is chemically about 60+/-3% silica, SiO2, but the amount of free silica is very small, if present at all - at most 2 or 3 percent. So no, you won't extract commercial powdered silica. Better than 99.9% pure silica is found very abundantly in some quartzites, a common sedimentary rock. So nobody is going to try to extract silica from other silicates.


Standardized scale for coastline length or mapping in general?

One standard that has be used by the USA is to measure the distant between points on the coast at intervals of 30 latitude minutes, as measured on a 1:1,200,000 scale map.

See chapter 5 of Measurements from Maps: Principles and Methods of Cartometry by D. H. Maling for further information and other standards that have been used.


How to calculate maximum and minimum mean monthly temperatures?

From my experience, first of all, you should calculate the hourly average, in your case should be the average of the 2 minimum and 2 maximum temperatures. (In your sample data you need the 0:00 hours of 2009-05-02, as it is covering 23 hours)

Once you have the average by hour in a day, you can go for the daily average, then monthly average and so on...

For the minimum and maximum, there is no average, it should be just one value. If you want to calculate a monthly minimum average, then it should be calculated with the same process, so there is just one minimum by hour (the minimum in the range, f.e. 0:00-1:00), then one average of all the hourly minimums to get the daily minimum, and the same system for the monthly one.

If you try, you will see that you don´t have exactly the same result than making a daily average. For your sample, the daily average by hour is 26.31 degrees and by the daily average of all data is 26.25 degrees.

Hope it helps!


Can Monin-Obukhov Similarity theory be generalized to tracers?

Yes, the equation can be generalized as you mentioned. The method used to drive it is pretty close to humidity and temperature formulas.

I will start with neutral case and apply law of the wall, it is pretty simple to drive the following equation with Fc as diffusive flux and K as an empirical constant (NOT von-Karman) and also you can get C* from here by setting z = z0:

Remind yourself that Monin-Obukhov length scale (L) is simply the ratio of shear production to buoyancy in TKE budget and is NOT tracer dependent.

Now back to dimensional analysis. The group of variables are unique to our problem are :

1) z/z0 , 2) C/C* and
3) **z/L

where C is mean concentration (C bar in previous equation). Similar to what we do for temperature and humidity. A ψc can be calculated by choosing the second and the third group as independent variables and we would arrive at your equation.

Regarding the Gaussian plume, Remember that the equations you posted are only applicable near a boundary and only used to drive eddy diffusivity close to the wall layer e.g. wind tunnel, ocean, and earth. If I recall correctly Gausian plume model use different diffusivities compared to these and are more appropriate to interior of the flow.


Does rain (temporarily) deplete the surrounding atmosphere of carbon dioxide?

Here is the mass-calculation. We will consider a column of the atmosphere with a footprint of 1m × 1m. This column weighs about 10,000 kg (per square metre). In these days of climate change we will assume the current average CO2 concentration is 400 ppm, yielding a total mass of CO2 in this column of 4 kg.
The rain doesn't wash out the entire thickness of atmosphere but only (in general) the lowermost troposphere. We will assume, generously, that some 2.5 kg of this 4 kg of CO2 is available to be scavenged by raindrops.
Now consider a cloudburst of raindrops, equivalent to some 100 mm  on the ground. So we have 0.1 cubic metres, or 100 kg, of fallen raindrops within our square metre column of air. The solubility of CO2 in air is strongly temperature dependent, up to 2.5 g per kg at 10 deg C. But at such a low temperature we couldn't achieve 100 mm of rainfall, so we will compromise at about 1.5 g per kg at 25 °C. So, assuming complete CO2 saturation within the raindrops (unlikely) our 100 kg of rain will contain 0.15 kg of CO2 , scavenged from about 2.5 kg of CO2 in the 'rained out' column of air, or about 6% of the low atmospheric CO2 .

Bear in mind that this assumes an enormous rainfall intensity, 100% CO2 saturation of the water and equilibrium chemical dynamics. After the raindrops hit the ground at least half of it will immediately re-evaporate back into the air, leaving, at absolute most, about 3% of the atmospheric CO2 leached out of the atmosphere that will be available to react with the soil, rock or biosphere. Also consider that this is but one of several important processes affecting CO2 transience, such as photosynthesis, respiration, volcanism, industrial pollution, etc. So the CO2 estimates that you read about are average values. Advection and turbulent air mixing should ensure that the CO2 regains approximately normal concentration within an hour or two after rainfall.


Limestones are usually categorized following the Dunham & Folk classification. Only very rare or special limestones were given a name and these are often named after the location where they can be found e.g. Travertine.

The images you provided are not very explicit which makes it literally impossible to clearly identify the limestone. Please consider next time to upload close up pictures that show the composition e.g. bioclasts and cements of the limestone.

However, there is a paper by the Geological Society of India were the authors date a limestone from the Jammu region which they refer to as Jammu limestone or Great limestone. The authors suggest that the limestones are from the Precambrian due to stromatolites that were found there in.

I hope this helps!


Does crustal thickness have anything to do with how life existed and sustained on Earth?

If the crust were the thickest layer or Earth, several things would happen:

It wouldn't be a "crust" any more, by definition. Because this is what a "crust" is: a thin layer on the exterior of something. However, if we assume that the mechanical properties of the crust (being cold and brittle etc) would extend deeper in the Earth, the following applies.
No mantle convection, or at least mantle convection weak enough to probably not affect the surface. Therefore, no volcanoes, no mountain building, no subduction, no recycling of volatile elements, no sub-seafloor hydrothermal vents.
If it's cold enough, the core probably solidified and there is no magnetic field.

A good example would be Mars. A planet hypothesised to have tectonic activity in the past, but not any more. The crust of Mars isn't the thickest layer (again - think of definitions), but it is thicker in absolute and relative terms when compared to Earth. I will leave the implications of "Marsifying" Earth on organisms for you to figure out.


Could a large burst of super-heated or super-cooled air cause tornadoes to fall apart?

Changing air currents is very difficult and energy intensive.  You'd need to alter an entire weather system - no easy feat.  If you heated a very large region of cool air you might prevent the spiraling that causes tornadoes to form, but you'd need to warm at least few states worth of upper atmosphere.   It would be an enormous undertaking.

There's also the logistical problem of how would you go about doing it?   Heating in principal can be done faster than cooling, presumably sending up a whole lot of hydrogen in a few hundred balloons and igniting it forming hot water-vapor, which as it condenses, would further heat the atmosphere.    Cooling warm air is harder as there's no quick and easy method to cool an enormous  volume of air, so I think heating the high cold air would be easier than cooling the low moist air, but it would still be an enormous effort and probably cost more in prevention than the tornadoes are likely to do in total damage.

http://images.slideplayer.com/22/6379142/slides/slide_22.jpg

There's no neat and tidy technological trick to get it done that I can think of.


No. Consider water vapor. Water vapor is a greenhouse gas. As the temperature increases, more water is evaporated. Since water vapor is a greenhouse gas, the temperature will increase. Clouds, however, form from water vapor, reflect sunlight.

The earth is not as linear as people would like.


Does ground-to-cloud lightning create crystals as well?

I would assume that any lightning bolt connecting to the ground would be capable of producing a fulgerite in the soil, regardless of the direction that the bolt "flows". Fulgerites are caused by the extreme heat of the lightning bolt, which fuses the soil (sand mainly) together into a type of glass. Since the extreme heat of a lightning bolt also causes the sound of thunder, it's safe to assume if you hear thunder from a ground to cloud strike, it can also cause a fulgerite.

Most ground to cloud lightning seems to flow from the highest points of very tall objects, such as sky-scrapers, radio towers, etc. Since the best fulgerites are formed in sand, it may be very hard to find a fulgerite caused by ground to cloud lightning. Perhaps on a sandy mountain peak?


What is the Calcite Compensation Depth and what is its significance for carbonate deposits?

The Calcite Compensation Depth is the depth below which all calcite minerals are dissolved. The solubility of calcite (and the amorphous variant aragonite) depends on both pressure and temperature. Under high pressure, low temperature conditions calcite is most soluble, and in deep parts of the ocean only siliceous deposits are found.

Typical values for the CCD are between 3000 and 4000 m, but since the CCD also depends on the amount of calcite in the water it can occur as shallow as 2500 m (in parts of the Pacific Ocean). These shallow zones are often caused by high biological activity of carbonate shell forming organisms.

Taking all this together it becomes clear carbonate deposits can form and/or be preserved only above the CCD.


How will the rising ocean affect aquatic life?

Biological communities (ecosystems) commonly change along topographic (bathymetric) slope - because conditions change along the slope. For example, there will be a temperature gradient with elevation along the side of a mountain, and gradients of temperature and the amount of incident sunlight reaching the sea floor just offshore. When climate changes, this can shift conditions up or down the slope.

The organisms of an ecosystem must be able to colonize any "new habit" that may be created by climate change in order to take advantage of it.  If conditions shift too quickly for the species to adapt by migration along slope, species may become extinct before they can become established in another area. For example, consider coral reefs, which are dependent upon depth, if sea-level rises too quickly, the population of surviving corals may become too small to successfully colonize reefs in new areas.

The answer to your question is complex. If you search the web for the term velocity of climate change you will find that your question is being actively researched by scientists.


It is possible to reduce global sea level via filling empty lowlands with ocean water?

Based on calculations of the effect of melting ice on sea level, we know that to effect a 1 mm change in global sea level requires around 360 km3 water. The largest lake by volume, Lake Baikal, contains just under 24,000 km3 of water. So if you created an equivalent lake you would lower sea level by 66 mm. At current rates of global sea level rise that would offset less than 20 years of melting ice and thermal expansion.


Just to expand upon my comments:

This page from CPC suggests that the error message is likely due to wgrib2 thinking subsequent arguments are actually additional grib files because they aren't properly given the - prefix.  That lead me to realize that you have a space between your last dash and grib which appears to cause the error:

  wgrib2 gfst.grb2 -match ":(APCP):" - grib gfst.grb2.small

should be

  wgrib2 gfst.grb2 -match ":(APCP):" -grib gfst.grb2.small

Hopefully that helps if anyone else comes across the issue at a later date!  You might also have forgotten a dash somewhere... or tried using too many arguments in an option?


What potential geoengineering technologies could help a country "achieve its Paris (agreement) targets"?

I think the third paragraph of the article hints at what might be the thinking.

In the next five years, the total area covered by artificial rain or snowfall will reach 5.5 million sq km, while over 580,000 sq km (224,000 sq miles) will be covered by hail suppression technologies. The statement added that the program will help with disaster relief, agricultural production, emergency responses to forest and grassland fires, and dealing with unusually high temperatures or droughts.

Firstly, rain will absorb some CO2 by creating small amounts of carbonic acid (H2CO3). Agricultural production would remove some CO2. Reduction of CO2 production via the possible prevention of grass & forest fires. This would also be aided by the supposed reduction of temperatures and droughts. With sufficient rain to ensure the Three Gorges Dam is always full, potentially consistently reliable hydroelectricity could be achieved, thus reducing the amount of CO2 producing energy sources used for energy production.
Finally, hail suppression technologies were mentioned. By eliminating hail one eliminates the potential for damaging hail to occur thus reducing the need to manufacture building products to repair buildings damaged by hail. It also prevents crop damage by hail thus eliminating the need to plant replacement crops.


Reisdual soil and the atmosphere influence

If you are including the early history of the earth, study of regolith from the Archean period has been used to indicate the oxidation state of the atmosphere. Different weathering products form, depending on the amount of oxygen in the air and dissolved in infiltrating rainwater. So the residual soil chemical and isotopic composition changed when the atmosphere became oxic. There are a few locations in South Africa, Canada, and probably other places where these soils were buried and preserved, (e.g. by lava flows near Flin Flon Manitoba Canada).


It all depends on the region you are interested on. For the North America region, you could use the North American Regional Reanalysis (NARR).

NARR is a "high resolution combined model and assimilated dataset. It covers 1979 to near present and is provided 8-times daily, daily and monthly". The best and easiest way to access the data is through NOMADS. There you will find data in several different formats (netCDF, GRIB...) and it has a resolution of around 32km.

If your interest is in global data, then you could try the NCEP/NCAR Reanalysis. It is a global reanalysis of the atmosphere from 1948 to the present with a resolution of 2.5 degrees. There is also the NCEP/DOE reanalysis with a similar footprint. I think you can get both of them from NOMADS.

All these products are reanalysis (therefore not forecast) products. If your interest is in forecast products, then you can use the North American Mesoscale (NAM) product. It has a resolution of 12km and it is available through NOMADS. The model they are currently running is a version of the Weather Research & Forecasting - Nonhydrostatic Mesoscale Model (WRF-NMM).

There is a complete list of NOAA model products available and a brief description of each in the NOAA NOMADS page.


Put a cylindrical beaker out in the open at mid day. Remove it at mid day on the following day. Measure the depth of the accumulated rainfall and divide by 24 to give the average rainfall per hour, and divide that by 6 to give the average per 10 mins. In the summer, some of your collected rainwater will be lost through evaporation, so to find that, put your beaker of water outside, but under some sort of roof. Measure the depth when you put it out, and measure it next day when you take it in. That will give an idea of losses due to evaporation, which reckoned in losses every ten minutes would by tiny. If there is not much rain but plenty of hot sunlight, things become tricky, because you will be measuring very tiny quantities. Other than that, you could camp outside and weigh your beaker every 10 minutes, but that's not something I would do myself. The roof I mentioned is only necessary if it is raining, because rain would destroy your figures for evaporation.


Is it possible to kickstart an hypothetical frozen earth with 0.6 ice albedo to an earth with an atmosphere, with just the sun at current distance?

The answer is no.
Explanation:
No atmosphere is equivalent to all molecules being able to evade to space (This happens on planets with low gravitational force). Thus also $H_2O$ molecules will evade and I guess that many molecules already evaded during the frozen state of the planet due to sublimation. So this could be the end of this answer.
But let's suppose for a moment, even if it is not realistic, that an atmosphere could form. Top of atmosphere power received from the sun is around $S_0 = 1368 \, \frac{\text{W}}{\text{m}^2} $ ($S_0$ being the solar constant). Assuming earth is a blackbody we can equate power received from the sun and power radiated from the hypothetical earth (see also Stefan-Boltzmann law).
$S_0(1-\alpha) \pi r^2 = \sigma T^4 4 \pi r^2$
$\alpha = 0.6$ is the albedo, $\sigma = 5.67 \cdot 10^{-8}$ is the Stefan-Boltzmann constant, $\pi = 3.1415$, $T$ is earths surface temperature and $r = 6371 \, \text{km}$ is earths radius. Simplifying and rearranging yields
$T = \left(\frac{S_0(1-\alpha)}{4\sigma}\right)^{\frac{1}{4}} \approx 222 \, \text{K} = -51.15°\text{C}$.
Taking a look at the phase diagram you provided, we see that at $222 \, \text{K}$ and low pressure water naturally occurs as gas. Given the assumption that an atmosphere could indeed form (for some magical reason someone increases gravtiy) the answer is yes an atmosphere could form.


How to distinguish an explosion crater from an impact crater?

A manmade crater would leave behind traces of the chemical(s) used to create it (C4, TNT, ANFO, etc.). Assuming the impactor were large enough, there would be traces of shocked quartz or other shocked stone in and around the crater. If the impactor landed in limestone, then there would be significant quantities of quicklime. (I'm purposely omitting thermonuclear devices here.)


Did a gamma ray burst contribute to the Ordovician mass extinction?

As a preamble, let me say that I don't know remotely enough on galactic dynamic to know if a supernova could have possibly been close enough during the Ordovician for Earth to be affected by a gamma ray burst, nor do I know enough about geochemistry to know if there are ways to detect such an event in the fossil record.

That being said, the questions that I'll try to answer are: do we need to invoke an extraterrestrial event to explain the Late Ordovician glaciation? does the taxa selectivity of the extinction event support the GRB hypothesis?

So let's look at the different hypotheses on how the glaciation occurred, the original conundrum being: how could a glaciation occur when mid-Ordovician $p_{CO_2}$ is believed to be up to 14 times Quaternary level? Brenchley et al. 1994 suggested that the Ordovician ocean circulation changed from a system having warm saline bottom waters to a system with cold bottom waters (i. e. a thermohaline instead of an haline circulation), which triggered a phytoplanktonic bloom, which then decreased atmospheric $p_{CO_2}$ and provoked an eutrophization of the ocean. Kump et al. 1999 argued in favor of a tectonically derived $p_{CO_2}$ decline: with the Appalachian and Caledonides orogenesis came an increased weathering which decreased $p_{CO_2}$. Of course the two hypotheses are not mutually exclusive since increased weathering also means increasing nutrients in seawater and therefore increasing primary productivity.

Another question is which groups went extinct during the glaciation: recent studies show that acritarchs (the most diverse group of phytoplankton known for that period) did not suffer from these events (Vecoli 2008); oppositely benthic group such as crinoids or brachiopods did (see Sheehan 2001 for a review); some pelagics groups such as graptolites and nautiloids did suffer as well during the event while some other didn't (radiolarians for instance). In summary there is no clear pattern, but there is also no reason to think that there was a preferential extinction of surface organisms over deeper-living ones.

So, does that answer the question: no; but it seems to me that GRB doesn't explain better the event that unfolded during the late Ordovician than other hypotheses (namely the ocean eutrophization and the continental weathering). Does it discard the hypothesis of a GRB: no; but since there is no direct evidence that it indeed happened at that time, and that we can explain the Ordovician events without, it seems, to me, more parsimonious to think that it didn't.

References:
Brenchley et al., 1994. Bathymetric and isotopic evidence for a short-lived Late Ordovician glaciation in a greenhouse period. Geology, 22: 292-298.
Kump et al., 1999. A weathering hypothesis for glaciation at high atmospheric $p_{CO_2}$ during the Late Ordovician. Palaeogeography, Palaeoclimatology, Palaeoecology, 152: 173-187.
Sheehan, 2001. The Late Ordovician Mass Extinction. Annual review of Earth and Planetary Science, 29: 331-364.
Vecoli, 2008. Fossil microphytoplankton dynamics across the Ordovician–Silurian boundary. Review of Paleobotany and Palynology, 148: 91-107.


Where can I find geomagnetic observations for the Indian Ocean region in 2017?

For surface data, a good place to start is Intermagnet, a global network of geomagnetic observatories. Their data download page lets you filter by time span and region, and sample rates down to the second are available for some observatories. The data are direct observations from individual observatories at fixed locations, and are not averaged over a region. (You mention in a comment that you couldn't find a station for ‘the northern equatorial part of the region near India’; for this region I'd suggest Gan in the Maldives.)

For recent satellite data, the Swarm mission provides an excellent resource. This page gives instructions on how to download their freely available data sets. Registration is required, but as far as I can tell it's free and available to anyone. They've also got an excellent online visualization tool which lets you explore their data interactively.


Will tropical cyclones form and be sustained in areas they previously were not due to global climate change?

The short answer is no.

Tropical cyclones (TC) develop and persist in conditions favorable to them:

1) Low Coriolis parameter $f = 2\Omega \sin{\theta}$, where $\Omega$ is the angular velocity of Earth and $\theta$ is latitude. If $f$ is small, the centripetal force balances the pressure gradient force in the gradient wind balance, and the radius of curvature becomes small. While this is one of the reasons why TCs form in the tropics, that still does not prevent the storm to move North and re-curve into Western Europe or Northern California. This limits the latitude extent of the region of TC genesis to approximately 5-30 N (or S). This factor is most certain and not subject to climate change.

2) TCs get the energy from sensible and latent heat fluxes at the surface. Thus, they form over the ocean and it needs to be warm. Historically popular threshold of sea surface temperature (SST) necessary for a TC to develop was 26$^{\circ}$C. Nowadays, we know that this is not enough - TCs need a significant thickness of the upper ocean to be warm in order to get enough heat to be sustainable. Another reason why the ocean is more favorable for TCs than land is surface friction - the air flow over the ocean surface is typically much more aerodynamically smooth compared to over land. Low wind stress and high heat fluxes are key. Though the wind stress is not going to change, heat fluxes may increase if the ocean heat content in the tropics increases (for example, by weakening of the Meridional Overturning Circulation).

3) TCs also need favorable atmospheric conditions in their environment - namely, high humidity (water vapor content) in the environmental air, and low wind shear (difference between wind in the upper and lower troposphere) facilitate TC genesis and longer life. These factors are, in my opinion, least understood of the three, especially in terms of their contribution to the vortex dynamics and vortex-mean flow interaction. This aspect is more likely to be subject to climate change compared to the others.

All this being said, we may see a change in the occurrence frequency of TCs in the future, and/or a change in the distribution of the extreme weather events. However, the mechanisms in the climate that would lead to this change are still not well understood. It is unlikely though that the TCs will start forming in new regions around the world.


Extratropical transition of tropical cyclone

No, it is not sufficient to just discuss the behavior as it moves into higher latitudes. ET occurs because of environmental reasons, not geographical reasons.

How much of a beginner are you? My answer below may be a bit over your head if you do not know much about tropical cyclones. If that is the case, I suggest looking back at the theory and basics of tropical cyclones (structure, maximum potential intensity, etc.) to get a good grasp of what separates tropical cyclones from extratropical cyclones.

If you are specifically looking at quantities, I suggest looking at cyclone phase space diagrams. The variables in these diagrams include the thermal wind for different levels, as well as baroclinicity. FSU has examples of cyclone phase space diagrams for different storms.

Edit: I remembered two recent articles that review ET. They are Evans et al. (2017) and Keller et al. (2019).


How to speciate EDGAR emissions for CBMZ?

I used the R package eixport (Ibarra-Espinosa et al., 2018) to download EDGAR data (5 and spec voc 4.3.2) and then include several speciations for chemical mechanisms according to Carter (2015) and Lopez-Norena et al (2019).
The functions to download EDGAR are commented. This means that you must download all NetCDF files before running chem_edgar.

library(eixport)
library(rasterVis)
#> Loading required package: raster
#> Loading required package: sp
#> Loading required package: lattice
#> Loading required package: latticeExtra
library(cptcity)
# 1 Get EDGAR ####
# get_edgar(dataset = "v432_VOC_spec",
#           destpath = "V50_432_AP/TOT/",
#           sector = c( "TOTALS"),
#           type = "nc",
#           year = 2012)
#
# get_edgar(dataset = "v50_AP",
#           destpath = "V50_432_AP/TOT",
#           sector = c( "TOTALS"),
#           type = "nc",
#           year = 2014)
#
# get_edgar(dataset = "v432_VOC_spec",
#           destpath = "V50_432_AP/TRO/",
#           sector = c( "TRO"),
#           type = "nc",
#           year = 2012, ask = F)
#
# get_edgar(dataset = "v50_AP",
#           destpath = "V50_432_AP/TRO",
#           sector = c( "TRO_RES", "TRO_noRES"),
#           type = "nc",
#           year = 2014)
#
# totals <- list.files(path = "V50_432_AP/TOT/",
#                      full.names = TRUE,
#                      pattern = ".zip")
# lapply(totals, unzip, exdir = "V50_432_AP/TOT//")
#
#
# tros <- list.files(path = "V50_432_AP/TRO",
#                      full.names = TRUE,
#                      pattern = ".zip")
# lapply(tros, unzip, exdir = "V50_432_AP/TRO/")
a <- chem_edgar(path = "EDGAR/V50_432_AP/TOT", chem = "cbmz_mosaic")
#> units:  kg m-2 s-1
#> Detecting the following files:
#>                                                           lncs
#> voc1   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc1_2012.0.1x0.1.nc
#> voc2   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc2_2012.0.1x0.1.nc
#> voc3   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc3_2012.0.1x0.1.nc
#> voc4   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc4_2012.0.1x0.1.nc
#> voc5   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc5_2012.0.1x0.1.nc
#> voc6   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc6_2012.0.1x0.1.nc
#> voc7   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc7_2012.0.1x0.1.nc
#> voc8   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc8_2012.0.1x0.1.nc
#> voc9   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc9_2012.0.1x0.1.nc
#> voc10 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc10_2012.0.1x0.1.nc
#> voc11 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc11_2012.0.1x0.1.nc
#> voc12 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc12_2012.0.1x0.1.nc
#> voc13 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc13_2012.0.1x0.1.nc
#> voc14 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc14_2012.0.1x0.1.nc
#> voc15 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc15_2012.0.1x0.1.nc
#> voc16 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc16_2012.0.1x0.1.nc
#> voc17 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc17_2012.0.1x0.1.nc
#> voc18 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc18_2012.0.1x0.1.nc
#> voc19 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc19_2012.0.1x0.1.nc
#> voc20 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc20_2012.0.1x0.1.nc
#> vpc21 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc21_2012.0.1x0.1.nc
#> voc22 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc22_2012.0.1x0.1.nc
#> voc23 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc23_2012.0.1x0.1.nc
#> voc24 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc24_2012.0.1x0.1.nc
#> voc25 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc25_2012.0.1x0.1.nc
#> co                 EDGAR/V50_432_AP/TOT/v50_CO_2014.0.1x0.1.nc
#> nox               EDGAR/V50_432_AP/TOT/v50_NOx_2014.0.1x0.1.nc
#> nmvoc           EDGAR/V50_432_AP/TOT/v50_NMVOC_2014.0.1x0.1.nc
#> so2               EDGAR/V50_432_AP/TOT/v50_SO2_2014.0.1x0.1.nc
#> nh3               EDGAR/V50_432_AP/TOT/v50_NH3_2014.0.1x0.1.nc
#> pm10             EDGAR/V50_432_AP/TOT/v50_PM10_2014.0.1x0.1.nc
#> pm25            EDGAR/V50_432_AP/TOT/v50_PM2.5_2014.0.1x0.1.nc
#> bc                 EDGAR/V50_432_AP/TOT/v50_BC_2014.0.1x0.1.nc
#> oc                 EDGAR/V50_432_AP/TOT/v50_OC_2014.0.1x0.1.nc
#> EDGAR data: voc1  voc2  voc3  voc4  voc5  voc6  voc7  voc8  voc9  voc10  voc11  voc12  voc13  voc14  voc15  voc16  voc17  voc18  voc19  voc20  voc21  voc22  voc23  voc24  voc25  co  nox  nmvoc  so2  nh3  pm10  pm2.5  bc  oc  units of gases: mol/km2/h
#> units of aerosols: ug/m2/s
# just for the plot, replaces 0 with NA

a$E_CO[] <- ifelse(a$E_CO[] <= 0, NA, a$E_CO[])
colors <- c(cpt(pal = "mpl_viridis", rev = F, n = 200),
            cpt(n = 100, rev = T))
levelplot(a$E_CO,
          col.regions = colors,
          zscaleLog = T)

Created on 2020-10-15 by the reprex package (v0.3.0)
Carter, W. P. (2015). Development of a database for chemical mechanism assignments for volatile organic emissions. Journal of the Air & Waste Management Association, 65(10), 1171-1184.
Lopez-Norena, Ana and Fernandez, Rafael & Puliafito, SALVADOR. (2019). ESPECIACION DE INVENTARIOS DE EMISIONES DE AEROSOLES Y COMPUESTOS ORGANICOS VOLATILES PARA EL MODELO WRF-CHEM, APLICADO A LOS ESQUEMAS RADM-2, CBM-Z Y MOZART
Ibarra-Espinosa et al., (2018). eixport: An R package to export emissions to atmospheric models. Journal of Open Source Software, 3(24), 607, https://doi.org/10.21105/joss.00607


When sea level rises, does the increased ocean area cause the earth to cool down somewhat?

As you say, land and water albedos are very different. Meaning that a square meter of water, in average, absorbs more energy from the sun than a square meter of land. Also water transfers heat vertically more efficiently than land due to convection and it also affects climate by providing a ready moisture source.

That said, changes in the surface of land vs water do have an impact on climate. However, the change in water surface area due to sea level rise is very small compared with other changes in land/water surfaces. Let's crunch some numbers to see it more clearly...

Lets consider a good approximate of the length of the global shoreline of 620,000 km (a precise number is impossible to get due to the coastline paradox). Now, at current sea level rise of 3.2 mm/year, 30 years would mean about 10 cm of sea level rise. If we assume that the typical slope is such that this moves the shoreline also 10 cm forward, the associated area increase would be:

$620000\, \text{km} \times 0.0001\, \text{km} = 62\, \text{km}^2$

And this is negligible compared with other effects like the drying of the Aral sea (~28,000 km$^2$), the construction of the Three Gorges Dam (1,084 km$^2$), or even the construction of the Palm Islands in Dubai (80 km$^2$).

Even if our very rough calculation above is multiplied by ten or even one hundred, the contribution of sea level rise would remain small compared with other changes.

At a global scale over the last 30 years there was a net increase of 58,000 km$^2$ of water surface, but mostly due to natural processes or large infrastructure projects. Sea level rise played just a very minor role in those changes.  Indeed the following figure from the paper Earth's surface water change over the past 30 years shows changes from land to water in blue and changes from water to land in green:

Now, what's the effect of this increased water surface area (even if it is not due to sea level rise), that's another question that I won't get into in detail. But in general it will be a warming effect, both because of the lower albedo of water, and because of the warming effect of low clouds. However, the actual effect will depend on where the new water bodies are located; some extra water near the sea wouldn't have the same impact as some extra water in the middle of a desert.


Oxygen is always divalent negative. An oxide has to be charge balanced, meaning the total has to be zero.

Therefore, some like CaO means you have Ca2+O2-.
Something like SiO2 is going to be Si4+2O2-.
Something like Na2O is going to be 2Na+O2-.

As you can see, the charges all sum to zero, given that oxygen is negative two.

Let's work out an example:

You have 1 moles of each: K2O, MgO, and ZrO2. You will have one mole of Mg2+, one mole of Zr4+, and two moles of K+.


Where can we see the noctilucent clouds?

Noctilucent clouds form during summer at high latitudes, such as between 50 and 70°N.  They are noctilucent because at their high elevation (80 km), the sun is still shining, although the sun is below the horizon at ground level.  Due to this high elevation, you can see them from several 100s of km south of their actual location.  This means the ideal viewing location is at around 55–60°N; the night there gets dark enough throughout the summer, while the noctilucent clouds a bit further north are still sunlit.

If you go too far north, you will not see them very well, because the night will be too bright.  I lived for 5 years at 68°N, and although they could easily be detected by ground-based lidar, I never saw any myself.


Placement of crustal thickness estimation from 1D inversion of surface wave dispersion curves

This is a very good question, not just important to seismic inversion, but also modeling in general.

Lets set this problem up differently. Lets say point's A and D are nodes.

Each node represents a system of equations, and these equations are only calculated on these points. Therefore, the model can only exist on the points in which they are calculated. Since B and C are dimensionally  between A and D, a smoothing factor must be imposed to graphically represent them. So while there might be a line in between A and D, the model only exists on points A and D. To find the model at point B and C, you would have to build them in your model, creating a higher resolution mesh.  This is perhaps why it is so important to have a dense seismic array when doing seismic studies.

So in your case, the model is dependent on information on information at two stations, making each node TWO STATIONS. This would mean that the it is impossible to give an exact geographic location to where the inversion is, just a generalized idea of between these two stations.


Can we carbon-date the remains of homo floresiensis found in 2003?

ScienceMag says:

  Rather than damaging the fossils by dating them directly, the team looked to the sediments in which they were found. They discovered pieces of charcoal in sediments at similar depths, and considered those to be proxies for the ages of the fossils themselves. The charcoal bits were dated to around 19,000 and 13,000 to 11,000 years before present.
  But Liang Bau boasts a devilishly complicated geological history, as layers of silt and clay interleave with layers of weathered limestone, loose gravel, and volcanic ash. In many places, these layers have been scoured by erosion, altered by seeping water, and jumbled by tectonic activity.
  ...
  Dating on the gravelly sediment layer containing the fossils suggested it was deposited between 100,000 and 60,000 years ago; just above it is a layer of volcanic ash that was dated to about 60,000 years ago. This suggests that the fossils themselves couldn’t possibly be younger than 60,000 years old, the team reports online today in Nature.
  To cap it off, the team has now directly dated the fossils themselves. Originally, researchers shied away from that analysis for fear of damaging them, Tocheri says. But this time, they felt they needed to do it. “It wasn’t until [we] were reasonably convinced that [the fossils] were probably older than 50,000 years old that we decided we needed to date them directly to be absolutely certain,” he says.
  The team dated three arm bones found at different locations within the cave during previous excavations. Using uranium-thorium dating—which is based on the radioactive decay of uranium and thorium isotopes in a material—they found dates ranging from about 66,000 to 87,000 years old.

I could not find how the "charcoal bits" were dated, but it would be in the range for carbon dating.


How many $\ce{^{14}C}$ measurements have been made?

How many have been validated by historic calibration, and what
  proportion (if any) yielded inconsistent results?

Often with an item that they want tested, a specific date isn't available so calibration isn't possible, but calibration can be done when dates are known.  Tree rings are most common and (though I've not read of this being done), samples from dead bodies from a specific battle or disease outbreak where a date of death is known.  Article here and here.

The calibration curve represents changes in the amount of C-14 present in the atmosphere which is also a factor.   There wouldn't be a charted curve if calibration hadn't been done quite extensively (see 2nd article above).

There's some room for bacterial or other contamination, especially with older objects, and contamination has lead some inconsistent results but that's not because the theory isn't sound but because of miss-handling.


In Earth-system models, the term "coupling" is often used in two ways.  The first is "offline" coupling, where output from one model is passed to another model for computation of some variable.  The second is "online" coupling, where the feedbacks are allowed to pass between the two models.  Online coupling is synonymous with "fully coupled".

A good example is when wildfires are modeled with coupled meteorology-chemistry models.  Historically, the aerosol emissions from the fire would be modeled by a separate chemistry model that only used the meteorology model as an input (e.g. offline coupling).  However, now you can fully couple (e.g. online coupling) the chemistry with the weather such that the heat and aerosol released from the fire perturbs the meteorological/radiation calculations in the next iterated time step.


Why does atmospheric oxygen remain so "constant"?

The main reasons the atmospheric oxygen remains constant are:

The sheer quantity of it. Not even a large forest fire will
measurably deplete it. Most of it is fossil oxygen created many
millions of years ago by photosynthetic organisms.
It is constantly being replenished by photosynthetic organisms,
mainly in the ocean.
Measurements of the percentage of oxygen in the atmosphere are a
modern phenomenon. There are no accurate measurements of atmospheric
oxygen in previous geological periods, but we know the percentage
has not always been 21 percent.


What are the key elements defining the separation between Jurassic and Cretaceous?

Short answer, there isn't one.

The J-K boundary does not have a well defined fingerprint or marker, because of this it is in flux with different studies constantly offering to tweek or redefine its date based on their own criteria.

https://www.sciencedirect.com/science/article/pii/019566719190001S

https://ui.adsabs.harvard.edu/abs/2017EGUGA..1912252L/abstract

https://www.researchgate.net/publication/236003223_Fixing_a_basal_Berriasian_and_Jurassic-Cretaceous_J-K_boundary-_perhaps_there_is_some_light_at_the_end_of_the_tunnel


Perple_X (http://www.perplex.ethz.ch/) is software designed to do exactly that.

It has thermodynamic and mineral property databases for phases in interest. This is pretty much automation of method 3 given by the other answer.

In short, the way it works: you input your bulk composition, pressure, and temperature, and it spits out the phase relations.

A bit of warning: this software is very poorly documented with many tutorials and guides referring to older version that don't work exactly like the new one. I recommend going on their discussion forum which is very active, and the developer himself is commonly there. He is usually very responsive and can fix bugs pretty much on the spot (time-zone constraints permitting).


Why is my pond / lake melting when the temperature is still far below freezing?

My guess is that since ice (and the liquid water underneath it) is much better at absorbing thermal radiation than air, then even if the air temperature is below zero, the ice can heat up in the sun and melt a little bit. It will presumably then refreeze at night when there is no sun to keep it warm.

This was probably also happening on the surface of the snow as well before you cleared it but you didn't notice it because there was no colour change.


Is the work "The photochemical origin of life" ,by A.Dauvillier, in line of principle still valid today?

Possibly, but they don't apply to today's world

I'm reasonably sure, without having read the book but having looked at summaries online, that Dauvillier was arguing that the conditions on Earth when life first developed were such that life would not have developed if the Earth were 2 C warmer.

First of all, you would need to specify from what baseline the 2 C rise was measured. There are many times in the past where the Earth was at least 2 C warmer than the present and covered in advanced life (possibly up to 10 C warmer at time during the Mesozoic). NOAA suggests that parts of the Neoproterzoic saw global temperatures of 90 F and up, and of course life managed to persist through that.

Since his book is about biogenesis in general, there isn't much comparison to the conditions on Earth today. On that early Earth where life developed, the sun was much weaker (a paradox not completely resolved). There was no oxygen and much more carbon dioxide, ammonia, and/or methane, depending on who you ask. There were also (obviously) no photosythesizing plants and no biological component to the carbon cycle.

Life has profoundly changed how the Earth is. The atmospheric dynamics of the early Earth are not comparable to those of our Earth, and thus a 2 C rise then has almost nothing to do with a 2 C rise now.

Again, I haven't read the book so I can't asses what specific theories Dauvillier made about the early Earth. However, it could be possible that both things are true: a 2 C rise 4.5 billion years ago would have sterilized the Earth forever, and a 2 C rise today would not.


As bon noted in the comments, that it the time it would take the gamma rays to reach Earth. Gamme rays travel at the same speed as all other forms of electromagnetic radiation, including visible light, so we will not have any warning. This kind of makes the "6000" number meaningless. We will know that the star exploded and the gamme rays will reach earth at the same time. The destruction of ozone will then probably be instantaneous (on a geological time scale).

From your quote:

  It has been suggested that a supernova or gamma ray burst caused the End-Ordovician extinction.

It has been suggested because there was no other plausible terrestrial cause for the mass extinction, so people started to look at extra-terrestrial causes. But a paper published earlier this year documents a mercury anomaly associated with the extinction event. This gives strong evidence for a volcanic cause for the extinction (similar to the P-T or K-Pg events), and there is no need to make up a gamma-ray burst.

David S. Jones, Anna M. Martini, David A. Fike, and Kunio Kaiho: A volcanic trigger for the Late Ordovician mass extinction? Mercury data from south China and Laurentia. Geology, July 2017, v. 45, p. 631-634, 2017, doi:10.1130/G38940.1


The tidal flow velocity is not the same thing as the mass movement. Think of the tidal flow as a pressure pulse that moves up the river. It moves much farther than the actual salt water movement. The extent of the brackish zone is much shorter. The relationship depends on the river flow and the shape of the estuary.

In your case, your source area is within the limit of saline intrusion so there is some mass movement upstream. Given that you are studying bacteria particles rather than dissolved salt, I would say that the limit of saline intrusion marked on your map is an upper limit for the distance it could move upstream. That is assuming that the bacteria haven't established a stable population that can reproduce and grow outward.


Google Maps and MapQuest have gathered data and information through subcontractors and their own internal efforts. Their information is proprietary and is very hard to gain access to (and most methods of scraping this data would violate their Terms of Service). It's generally not considered a reliable source for getting anything beyond geocoded addresses.

An alternative method for getting more specific geographic data (e.g. building footprints, forest extents, roads/highways, POIs, etc.) is through the OpenStreetMap Project. This information is Open and crowd-sourced with very few limitations. Specific information can be grabbed through their Overpass API or can be downloaded as a whole in their pbf format which can then be converted to shapefile/GML.


Geological evidence about climate change: has there ever been a period with a rate of climate change as great as it is today?

Quick answer: yes.

But please read the following comments and explanations:

Most statistics about climate change are not based only in the 150 years of instrumental records. We have many good temperature proxies that go back between a millennia and 70 million years. Among them: tree rings, growth bands in corals, layered marine sediments, bog and lake sediments, stalagmites and stalactites, ice cores (800,000+ years), and isotopic composition of shells of single-cell organism called foraminifera. This last one can be used to estimate the temperature of the deep ocean as far back as 70 million years.
Although, the interpretation of the isotopic composition could be tricky, the caveats do not change the general picture presented by this long term temperature record. Here is a reconstruction of temperature based on foraminifera shells.

You can see that there were long periods of time with temperatures much higher than today. However, when it come to the rate of change this record doesn't have the resolution to answer your question.
As a first remark, note that we don't have a reliable temperature record going 400 million years back, and for the ones that do extend multiple million years, the resolution is not good enough to see quick climate change events as the one we are experiencing now.

However, we don't need to go that far back to find climatic changes greater than the one we are experiencing today. Such changes are actually visible in the 800,000 years records recovered from antarctic ice cores. And actually, the best examples come from high-resolution Greenland ice cores that go only about 110,000 years into the past.

One of the most studied quick climate changes is the one after the Younger Dryas about 12,000 years ago. Considering changes in the chemical composition of the atmosphere, and proxies of temperature, the data suggest that climate change after the Younger Dryas and other previous ones were more dramatic than the cumulative changes in the last 200 years. And such dramatic changes happened in periods as short as 40 years. The end of the Younger Dryas was associated to changes in temperature of 8 °C or maybe up to 15°C regionally, accompanied by two-fold changes in precipitation and methane concentrations (reference 1, reference 2)

Unfortunately the second reference (a Nature paper) is behind a paywall so I'll add here figure 4, the most relevant to this question.

You can see how fast are the changes in methane concentrations and $\delta^{18}O$. As a rough reference, a change of one unit in $\delta^{18}O$ is equivalent to a change in temperature of 2 °C, therefore the big jump in the figure is about 10°C.

Now I could argue that given that agriculture appeared just after that change (~12,000 years ago). When assessing if we have faced in the past a climate changes as dramatic as the one we are observing now you have to focus on what happened after that time. And notably, since then, the climate have been very stable. In fact, the change we are experiencing now is the largest after the invention of agriculture (previous references and this one).

As a corollary, it is important to realize that Earth's climate is much more chaotic and capable of large changes in short periods that what you would think by looking at the written history, and that we have enjoyed a long period of calm that at some point, sooner or later will be followed by changes unprecedented in human history.
The equilibrium we have enjoyed might be a kind of unstable equilibrium, and you might not need a very large perturbation to upset that equilibrium and send the system into a large climatic swing.


Source of water for the Great Artesian Basin in Australia

Many studies, observations and measurements indicate that a great deal of the water recharges from the eastern highlands (Great Dividing Range).  This answer focuses on Governmental reports (including the CSIRO)

According to the CSIRO report Hydrostratigraphy, hydrogeology
and system conceptualisation of the Great Artesian Basin (2012), the Great Artsian Basin consists of complex geological and hydrogeological features.  This extensive study of the basin indicated no recharge from Papua New Guinea, stating that the recharge areas as being from folded Mesozoic rocks surrounding the basin in the central and southern parts, and Cenozoic aged recharge areas around the Gulf of Carpentaria in the north.

The recharge areas of the Great Artesian Basin are, according to the Australian Government Department of the Environment is mainly from rainfall on the highlands (near to the western margin of the Great Dividing Range) to the east of the Basin (with some from the western margin), as shown in the image below (from the Dept webpage):

Source:after Habermehl and Lau (1997). The shaded patterns broadly represent the
recharge area; arrows represent modelled flow lines after Welsh (2000). Dashed
lines represent spring clusters updated from Habermehl.

One major observation is that the top of Cape York is indicated as a recharge area, however, the CSIRO report details that this is recharge area is the Coen Inlier, just to the south of the shaded are.  Also noted is that there is discharge into the Gulf of Carpentaria in the north - according to the CSIRO, the basin extends into the Gulf of Carpentaria.  Although in all 3 reports there is no mention of recharge through the Torres Strait, the most any such discharge could influence, is the part of the basin in the Cape York/Carpentaria area.

A cross-section of a section of the basin is show in the image below (from the Queensland Government WetlandInfo webpage, clearly modelling the recharge areas (for the most part) being from the highlands on the eastern margin of the basin:

Additional References

Habermehl MA and Lau JE 1997, Hydrogeology of the Great Artesian Basin (Map at scale
1:2500000), Australian Geological Survey Organisation, Canberra

Welsh WD 2000, GABFLOW: A steady state groundwater flow model of the Great Artesian
Basin, Bureau of Rural Sciences, Canberra.


The effect of the 2019-2020 bushfires/wildfires in Australia

The total area burned was 12.6 million hectares, or 126,000 square kilometers. This is equivalent to:

The US state of North Carolina (125,920 sq km)
The US state of New York (122,057 sq km)
The US state of Mississippi (121,531 sq km)
North Korea (120, 408 sq km)
96% of Greece (130,647 sq km)
52% of the United Kingdom (241,930)
36% of Germany (348,672 sq km)
22% of France (549,970 sq km)
45% of Ecuador (276,841 sq km)
10% of South Africa (1,214,470 sq km)
20% of Australia’s forests
Nearly twice the size of the 2019 fires in Siberia
5.5 times the size of the 2019 Amazon fires
6 times the size of the 2018 California fires

The amount of carbon dioxide emitted was 434 million tonnes. This equated to over three-quarters of the 532 million tonnes Australian industry emitted in 2018-19. Air quality during the fires was up to 20 times higher than hazardous levels.
The smoke encircled the Earth and discolored the snow on the alpine regions of New Zealand leaving it caramel colored.
The number of people affected by smoke for the fires was 11.3 million, or 57 percent of the population of Australia.
The estimated number of animal killed by the fires is 3 billion (revised on 28 July 2020, from 1 billion animals, when updated information was available). The breakdown by animal type is:

143 million mammals
2.46 billion reptiles
180 million birds
51 million frogs

28 July 2020
Substantial summary of the fires in Wikipedia.


Pumped systems are much more common. However, there are some artesian type hot springs where the water flows spontaneously and is not replenished in the immediate area.


How can we have "floating" and convection currents in a non-liquid mantle?

Is the mantle solid?
It's all a matter of timescales. The mantle is undoubtedly solid (except locally in the uppermost regions where melting can occur) but on a long enough timescale it can display plastic behaviour under high temperatures and pressures, with a viscosity on the order of $\text{~}\mathrm{10^{21}~Pa~s}$ (based on estimates from isostatic rebound after melting of ice sheets). Think of plasticine - it is obviously solid but it deforms easily under stress. This is how the mantle behaves on long timescales at high temperatures and pressures. On short timescales the mantle is a brittle solid and this is what allows it to transmit seismic S-waves.

Why does the crust 'float' on top of the mantle?
The answer to this is quite simple - the crust is less dense than the mantle and so on the long timescales, where the mantle is ductile, the crust does not sink into the mantle (except at subduction zones but that's another story). Granitic continental crust has an average density of around $\mathrm{2.6~g~cm^{-3}}$, basaltic oceanic crust is around $\mathrm{3~g~cm^{-3}}$, and the upper mantle is around $\mathrm{3.5~g~cm^{-3}}$.

How does convection work in the mantle?
The details of mantle convection are a subject of active research but all geologists agree that the mantle does convect vigorously and that this is the major form of heat transport from the core to the crust. If you calculate the Rayleigh number for the mantle you come out with $R_a~\text{~}~10^6$ which indicates that convection should be vigorous. On the other hand, the thermal diffusivity of the mantle is very low ($\text{~} \mathrm{10^{-6}~m^2~s^{-1}}$) and so conduction is not the dominant form of heat transport.


How straight is the Kola superdeep borehole?

Borehole drifted from straight vertical by ~840 meters over 12,000 meters.  All drill-bore wander side to side some and Kola borehole did not drift much until depth exceeded 5000 meters.

See page 102 in the linked document.

Typical rotatory drill heads designed for vertical drilling can be steer to a small degree by using a simple concept: point the bit in the direction that one wants to drill. A common way to achieve this is by the use of a bend near the bit in a down hole steerable mud motor. the bend points the bit in a direction different from the axis of the well bore.

By spinning the drill head at a different rate vs the drill stem, allows the bit to drill in the direction it points.

Reference: PDF document gives an excellent technical summary of the project.


Venice can't really be flooded by rivers, since there are none worth mentioning throughout the city.
High tides are predictable, yes.
Take a look at how Venice is situated. The historic city is sheltered behind low sandbanks/islands, which form the foremost coastline. Still the laguna is - obviously - connected to the open sea. Meaning: Huge waves, like in the open sea, wont rush through the city's channels, since they are dispersed by these islands. Still, in some images the water is quite choppy - a sign for rather windy conditions. Furthermore, all the houses of the city act like additional "islands", calming the surface of the water by dispersing larger waves into smaller and smaller ones. However, wind does not only create waves, it pushes the water also into the direction it is blowing to. In case of the Scirocco, which blows from northern Africa across the Mediterranean right into the Adriatic Sea, at which northern end Venice is situated. Thus, this wasn't simply a high tide, it was a spring tide, a combination of favourable planetary alignment and wind conditions. And, as already commented, winds/weather are quite hard to predict.

The whole process actually has a local name: "Acqua alta". It is nothing new, simply the intensity was noteworthy.


Why does the colour of amethyst fade if exposed to too much light?

The reason why amethyst loses its colour in sunlight is due in no small part to what impurity in the $\ce{SiO2}$ crystal structure gives the vivid purple and violet tones of amethyst.

According to several sources (1),(2),(3), the main source of the colour is naturally irradation-borne tetravalent iron $\ce{Fe^{4+}}$, which is formed via naturally occurring gamma radiation altering trivalent iron $\ce{Fe^{3+}}$ during crystalisation (3).  Other elements exist as impurities but are far less important considerations for the colour produced (3).

The tetravalent state of iron is inherently unstable in 'normal' surface conditions and the process is reversible due to prolonged exposure to natural sunlight (3).  Some research and experiments have demonstrated that some of the bleaching is caused by the UV portion of sunlight (4).

References

(1) Amethyst, Mindat.org

(2) Dudushenko et al. 2003, What Oxidation State of Iron Determines the Amethyst Colour?, ICAME 2003

(3) Hatipoğlu et al. 2011, Spectral, electron microscopic and chemical investigations of gamma-induced purple color zonings in amethyst crystals from the Dursunbey-Balıkesir region of Turkey, Radiation Effects and Defects in Solids: Incorporating Plasma Science and Plasma Technology

(4) Nunes et al. 2013, Spectroscopic study of natural quartz samples, Radiation Physics and Chemistry