There are apparently several ways of estimating total energy release in volcanic eruptions, all of them approximate. Energy is released as heat, vibrations, deformation of rock, kinetic energy of ejected material etc. Calculating an exact energy budget is hard.

The  Volcanic Explosivity Index (VEI) indicates how much volume the ejecta of the eruption takes up. One can estimate the energy release as a function of VEI class $M$ as $E=10^{aM+c}$ Joule where $a\approx 0.79$ and $c = 14$ (based on de La Cruz-Reyna 1991). That was in turn based on estimates from Yokoyama (1957).

Another way of estimating is to look at seismic signals and calculate how much energy the eruption must have had to produce the measured waveforms. Seismologists have fairly decent models of the scaling of energy with shaking intensity, and one can estimate how much it attenuates with distance.

A third way is to consider how much the pressure in the magma chamber is reduced times the reduction in volume, $E=\Delta P\cdot V$. A pressure drop of 5 MPa is apparently typical, and the volume reduction is proportional to the ejected volume (with some scaling factor from packed rock to ejecta).


What can we learn by studying lunar atmospheric tides?

This is a partial answer detailing some of the recent research in lunar atmospheric tides.  Many of which go beyond the 27.3 and 13.6 day cycles discussed in the Guoqing, 2005 paper, referenced in your question.  There has been some considerable research in this in recent years (an example is this list from Google Scholar of research since 2013).

A couple of examples are explained below that show that all manner of lunar cycles seem to have an effect on the Earth's atmosphere, generating a complexity of tides that tidally affect all layers of the atmosphere.  As we've been able to take long term measurements of various atmospheric parameters (most notably temperature, pressure and velocity) we have been able to come across patterns that suggest that several lunar cycles have made an imprint on them - in a way, suggesting that all lunar cycles have an affect on our atmosphere.

The lunar semi-diurnal cycle has been found to have a definite signature in the amplitude and phases of the temperature field of parts of the atmosphere between 20-120km altitude, according to research presented in the article A global view of the atmospheric lunar semidiurnal tide (Paulino et al. 2013) with the most pronounced signature observed in the lower thermosphere region.

Observations made between 1947-1994 in the article Long-Term Lunar Atmospheric Tides in the Southern Hemisphere (Wilson and Siderankov, 2013) have detected 4 roughly equidistant standing-wave summertime patterns with mean sea level pressure (MSLP) and sea-surface temperature (SST) consistent with being influenced by the 18.6 year Draconic lunar atmospheric cycle.  Superimposed on these is evidence of the SST's being affected longterm by the Perigee-Syzygy (or 'supermoon') lunar cycle.

A consequence is that the standing-wave pattern of the MSLP will interact and cause abnormal atmospheric pressure when passing over the semi-permanent South Pacific subtropical high roughly every 4.5 years, the consequences are that these affect the strength of the East-Pacific trade winds and according to the authors, may lead to conditions that "preferentially favor the onset of La Niña/El Niño events."


You don't need much of a depth to be able to stop a meteorite. Less than 100 m water depth should be enough to stop such a meteorite as shown in the provided link without any particular crater on the sea bed.

The Physics part of the story is provided here;

The rest is mathematics.

Short. At collision all the kinetic energy is transferred to Pressure, and thereafter this pressure is again transferred to kinetic energy; it is explosion. Very simply said it's Bernoulli principle.

By this reason it doesn't penetrate practically any deeper in water than in Earth, and as the water then smooths up you have no crater. A very simple scaling might be made with density; typical rock / water; 2.3/1 depth.

If you need some visual proof, try this video;

https://www.youtube.com/watch?v=cp5gdUHFGIQ


The AQI calculation does not require that all pollutants be measured.  Instead, it uses the pollutants that are available and then uses a function (chosen by the overarching regulatory agency) that equates health risk categories to the pollutant concentrations.  The pollutant with the highest health risk (at present concentrations) will effectively determine the corresponding AQI.  See here for how the USA EPA computes their AQI.

In order to detect the most commonly monitored pollutants, you would need an ozone analyzer and a PM2.5 monitor.  This is quite expensive.  A good single-pollutant monitor will cost thousands of dollars to purchase and many continuing costs.  You will also need calibration equipment and standards.  Depending on what AQI network you will be using as a reference, the model of instrument that you use will have to meet certain specifications in order for the data to be valid.  Teledyne is an example of a company that makes equipment that would meet the qualifications for the USA AirNOW network.  You may also find of interest their nice AQI calculator.


Yes, polar ice can melt -- significantly, if not completely, with substantial effects on human civilization. And it can stabilize and recover, but the question is at what pace relative to human civilization.

There are generally three types of polar ice:

Ice sheets: "An ice sheet is a mass of glacial land ice extending more than 50,000 square kilometers (20,000 square miles). The two ice sheets on Earth today cover most of Greenland and Antarctica."
Ice shelves: "Permanent floating sheets of ice that connect to a landmass."
Sea ice: "Sea ice is frozen ocean water. It forms, grows, and melts in the ocean. In contrast, icebergs, glaciers, and ice shelves float in the ocean but originate on land."

Sea ice is usually 1-2 meters thick; shelf ice is 100-200 meters thick; sheet ice is one to several kilometers thick.

The poles differ significantly. It's often pointed out that the Arctic is an ocean surrounded by land and the Antarctic is land surrounded by ocean. The North Pole is occupied by sea ice, about half of which melts every summer and reforms every winter.

At the other extreme are the ice "caps," more or less the ice sheets in Greenland and Antarctica that extrude ice in the form of glaciers and ice shelves that continuously flow into the ocean, breaking apart and melting.

To take just Greenland: Greenland has had some degree of glaciation for ~38 million years, but lost much or almost all of its ice during a warming period about 400,000 years ago, suggesting that the current ice sheet was created in that time.

  The evidence suggests nearly total ice-sheet loss may result from
  warming of more than a few degrees above mean 20th century values, but
  this threshold is poorly defined (perhaps as little as 2 °C or more
  than 7 °C).]5

(That melt ice is equivalent to about 7.3 meters of global sea level rise.)

So, yes, the ice sheets can melt away; how quickly they can melt will be driven by the amount and pace of CO2 emissions; the extent of that melting will be affected by the duration of that CO2 in the atmosphere and the impact of potential feedbacks.

The formation of an ice sheet -- glaciation -- can occur relatively rapidly in the correct conditions, according to this IPCC Assessment report on paleoclimate, which notes glaciation occurring in some regions of the world within a period of centuries.

In the short term, the most obvious impact we're seeing from global warming is the steady decline in the extent of Arctic Sea ice, at about 2.6 per decade since the satellite record began in 1979. Research suggests that this ice can come back, eventually:

  The central finding of this study is that sea ice loss is fully
  reversible in a state-of-the-art GCM over a range of CO2
  concentrations from the 1990s level to nine times higher. We find no
  evidence for threshold behavior in the summer or winter ice cover in
  either hemisphere. Thus if tipping points exist for future sea ice
  retreat in nature, it is for subtle reasons, i.e., through processes
  that are absent or inadequately represented in this model.

However, this team of researchers suggested an extensive project to prevent a worst-case scenario:

  This loss of sea ice represents one of the most severe positive
  feedbacks in the climate system, as sunlight that would otherwise be
  reflected by sea ice is absorbed by open ocean. It is unlikely that
  CO2 levels and mean temperatures can be decreased in time to prevent
  this loss, so restoring sea ice artificially is an imperative. Here we
  investigate a means for enhancing Arctic sea ice production by using
  wind power during the Arctic winter to pump water to the surface,
  where it will freeze more rapidly.


The WMO report Instruments and Methods of Observation has a chapter on Measurement of humidity and a separate chapter on Measurement of upper-air pressure, temperature, humidity. The first deals with instruments used for surface measurements. The second deals with instruments used for measuring vertical profiles, which have to deal with a larger range of temperatures and pressures.

For the surface instruments they list:

Gravimetric: take an air sample, extract all the water and weigh it (typically  used for calibration);
Chilled mirror: dewpoint or frostpoint: used for observations and for calibration;
Salt-solution: matching vapour pressure of a salt solution to atmospheric vapour pressure: used in automated weather stations;
Psychrometric: comparing wet or ice bulb temperature with actual temperature - used in observations and calibration;
Sorption methods: using hair or an alternative which stretches when wet, or using a material with a electrical resistance or capacitance that changes when wet.

In other words, the professionals use a lot of different methods.


But I don't understand the part of "degradation action" in the question, I think underground water only replaces the plant material in trees...

Degradation refers to the process of aqueous dissolution of the organic materials; the fact is, organic materials are generally quickly dissolved after the death of a living organism...degraded into nothing before the fossilization process can even start. (Think of the carbon cycle and how organic compounds are re-used over and over again over the eons of life on this planet.)

It's a bit of a misnomer in this case because it ignores the simultaneous replacement of that organic matter with inorganic siliceous materials.


If the Kola Superdeep Borehole were opened today, what would come out of it?

The only reasonable hypothesis is that it is filled with whatever it was filled with when the well was sealed.

A 12km long pipe with a sealed end is not going to have its contents replaced with something else easily. You could theorise that an intrusion of gas at the bottom opening of the pipe could expel liquid by replacement - possible, but slow.


That is the multimillion dollar question! "looking for surface formations" is indeed one way, and it was the main method of exploration in the past. This does not necessarily mean that you directly see the ore deposit in front of your eyes. Many ore-forming systems are accompanied by different kinds of alteration (for example potassic or argillic alteration) that are not too hard to see in the field. Once you see them, there is a possibility that an ore deposit is nearby.

Other surface methods include, among others, looking at rivers sediments. Since rivers transport soils and rocks from upstream, sampling the sediments may reveal an anomaly in a certain commodity of interest that may lie somewhere upstream. It is also possible to use satellite data - by looking at certain wavelengths it is possible to estimate the mineralogical composition of the surface. This may give hints on the possibility of mineralisation. I've even seen cases where people used different kinds of vegetation that grows on different lithologies!

Surface methods, however, require that the mineralisation will be close to the surface, and the truth is that most of the ore deposits that satisfy that requirement have already been found. This is where geophysical methods come into place. Gravimetric, magnetic and seismic studies probe the earth below the surface and may provide exploration targets, which are then drilled to see what's actually in there.

Mineral exploration is a hard business with much more failures than successes. That said, cases of serendipity are not unknown in exploration. Also, changes in global economics, production costs and increasing/decreasing metal prices may change what is actually an economically feasible ore deposit. The metals are always there - but is it actually worth taking them out?


Just to reiterate some of the points previously said here:

Continental crust fragments that collided are sticky. This results in mountain belts that essentially "glue" the two crusts together.
Subduction of a plate that contains both oceanic and continental crusts underneath continental crust will inevitably lead the the complete loss of the oceanic crust, and the gluing of the continental crust to the other one. India and the Himalayas are an example of something like this with all oceanic crust lost to the mantle, and the Mediterranean is an example of an almost completely subducted oceanic crust (aka the Tethys), with the formation of a mountain belt (Alps) and soon have two continental crusts glued together (Europe and Africa).

  it could also be subducting AWAY from an adjacent plate also containing continental crust

"Away" on a sphere means "towards" in the other direction. It's all relative here.

  or at least lower the probability of all continental crust being
  annealed at one time

They don't have to be annealed at one time. They just have to be annealed for long enough, without rifting, so all end up in one place.

  is how all these pieces land together again & again so improbably
  frequently

Improbably frequently? The last one existed about 300 million years ago, and the next one will form only in about 200 millions (more or less, depending who you're asking). In geological history, there are only two confirmed supercontinents, Pangea and Rodinia. Anything earlier than that is pure speculation (although educated speculation). I wouldn't call "twice" in 4.5 billion years "frequent".

I can also demonstrate by example. Today, there is only one rift that is properly breaking up a continent. This is the East African rift, and the Red Sea is a nascent ocean that is spreading now. But, there are more than one collision zones. The Australian plate is moving northwards, and soon will stick to SE Asia. India is already stuck there. Asian plate is stuck to European plate (Urals in Russia are the suture zone). Arabian plate and African plate are moving northwards as well (Alps, Zagros, all those mountain belts are the suture zones). The Pacific ocean used to be a whole lot bigger (Panthalassa Ocean). One oceanic plate is already underneath North America. The subduction rate of the Pacific Plate is the fastest of all subduction zones, and in not too long ago America (particularly North) will stick to Asia. The Atlantic Ocean has no subduction zones, so it will grow to become the new Panthalassa Ocean, with most other continents forming one single supercontinent.

  the break-up is of no particular relevance, and seems to be straight-forward - plate movement under the cratons

Actually no. The "cratons" are already a single plate, glued together from several other plates. The break-up usually occurs because of

  build-up of mantle heat under the insulating continental lid, will ultimately cause rifts to begin and start to form young oceanic crust (Arkenstein XII from the comments).


Why does the road appear wet on a sunny day?

This optical illusion is due to refraction of visible light due to density gradients near the surface and the fact that the index of refraction in a medium is dependent on the density of the medium.  In an atmospheric density gradient light will bend toward the direction of increasing density.  When it is cool at the ground and warms up with height this effect bends light toward the ground and when it is hot near the ground and cools with height this bends light toward the sky.  This is particularly strong over a road surface, which can be much hotter than the surrounding land surface.  This produces a sensible heat flux that warms the air over the road and can produce exceptional temperature gradients near the surface.

This strong temperature gradient near the ground is also a significant density gradient and when you look through it toward the horizon you are actually seeing the sky.  Photons that would normally illuminate the surface of the road are instead refracted by the density gradient and are bent toward your eye.  This only works for specific angles determined by the actual density gradient and this is why the mirage always appears at a certain distance.  You never really get closer or further from the "water" and you may be able to see road surface beyond the illusion.

Here is an image that describes the effect:

 Image licensed CC-BY by The School of Physics UNSW

This illustrates a the effect of a near-surface density gradient that is low density (warm) at the ground and increases (gets colder) with height.  The photons from the sky that pass close to the road are refract toward the observer and you see a false image of the sky as an inferior mirage.  The other photons do not pass through the strong density gradient and are not bent and you see the true positions of the objects.


0.07% of the mass of the Earth is estimated to correspond to carbon atoms (computed from data on Abundance of the chemical elements that comes originally from this paper)

The following table is from the above link and show the relative abundances on Earth in parts per million of mass:

The original table in the source paper (which correspond to Chapter 1 in, EARTHQUAKE THERMODYNAMICS AND PHASE TRANSFORMATIONS IN THE EARTH'S INTERIOR) is this one:


First, don't take that graph too literally, it is just a cartoon version and isn't quantitatively correct.

The USSR heavily subsidized fertilizer until 1988.  When they ended the subsidy, fertilizer prices increased to market prices and use of fertilizer decreased.  Fertilizer use decreased further after the USSR fell a couple years later.

Fertilizer use in France, Germany, UK and Japan peaked in the 1980s and contributed to the decline.


Why is the upper atmosphere brighter than the lower atmosphere in some photos from space?

The glow observed in those pictures in the upper layers of the atmosphere is the airglow from OH molecules. OH emission peaks between 75 and 105 km of elevation (Blamont and Reed, 1967) with intensities peaking at different wavelengths, the most prominent peaks in the visible spectrum are 557nm (Green), and multiple other peaks between 620 and 750 nm (red)

In 1965 the OGO-II satellite was launched with the propose to measure airglow, the following image show a typical altitude vs intensity profile:

From Blamont and Reed, (1967). The peak around 100 km is mostly due to OH airglow and the broader peak around 250 km is mostly due to atomic oxigen.

Regarding the color observed in the pictures, while it is difficult to trust them due to photo editing, they are consisten with OH airglow, in the greens, yellows and reds. This is the airglow spectrum from Broadfoot  and Kendall (1968), where I've highlighted in yellow the most important emission bands of OH in the visible range:

To get a sense of the color associated to each band here is a approximate scale (remember 1 nm = 10 Å)

From wikipedia

The fading yellow glow that goes below the brightest band can be explained as the OH glow at the same altitude band (75-105 km) but originating from the part of the atmosphere that is closer (or further) to the spacecraft from which the picture was taken. As that altitude band is a shell around the Earth and not a ring. For the same reason the peak intensity in the picture is likely a bit lower than altitude of the peak in emissions.


What is Stock or Overflow Pit? Is it a terminology in geography? What is the correct word for it?

Never mind I think I found what it is...

It is a tank that has a stock pit on the allotment. The tank usually about 30 feet radious and has a windmill.  It looks like this

http://www.panoramio.com/photo/9687839


How to predict when the pressure will change

Predictability of weather and climate is currently an active and lively research topic. I will try to giove some (very)  brief information on how it is normally done.

The best idea would be to use a weather (atmospheric) model, which is a numerical model that solves the Navier-Stokes Equations to bring prognostic information of the atmospheric state, for the next couple of days. This allows us to get a reasonably good prediction of high-low pressure zones within a week or so, which I intend is your goal.

Since you mentioned Windy.com, this is already a good source of information on weather prediction, probably one of the best compilation of weather models you can get nowadays. In the bottom right corner of the screan in windy.com (if using a desktop), you will see the acronyms GFS, ICON and ECMWF, for example. These are three models developed by possibly the three best centers in the world (from the USA, Germany and UK, respectively). A similar user-friendly interface, focusing on GFS is available at Earth Nullschool. They all bring a timer, so that you can choose the time of your prediction. Since you are asking specifically about a pressure system, I will assume you know how identify it in the images provided by these interfaces.

The predictability of weather for the next few days is good, and the predictability of "seasonal climate" is not bad either. For some time scale in between (subseasonal), there has long been a "grey zone of predictability". This is where cutting-edge research in Climate Science currently takes place. Sources of predictability, generally comes from a thorough understading of climatic phenomena (e.g. ENSO, NAO) and their relationship with the predicted variable. The NAO is known to modulate weather in North America and Europe in the day-to-day time scale, for example. ENSO is the dominant factor for tropical latitudes, with a lower-frequency variability.

This type of research is normally done using numerical weather and climate models, not so different from the ones in windy.com, often combined with statistics.

To reed further in the seasonal and decadal time scales.


Do ice crystals form in running super-cold water?

A snippet from the linked question:

Fred says:
Also, while water is flowing its potential energy is constantly being converted to heat energy that resists freezing on the molecular level and subsequent crystallization.
For flowing water to freeze, the temperature would have to be exceptionally cold


First thing is that the sea-level wasn't necessarily that high when the reef was growing, Hondurus is on the edge of the Caymen Trough Fault Zone and experiences quite high rates of uplift, (relatively speaking, your fingernails actually grow faster but over long periods it builds up). So the Coral reefs you're seeing high and dry could be quite recent in geological terms and laid down at or close to current sea levels.

Live Coral is a thin skin of either algae or tiny animals called polyps over what is essentially already Limestone. The live coating builds up this Limestone in order to 1. protect itself and 2. gain advantageous position as far as sunlight and nutrient rich currents etc... Once the coral builders die, which can happen within minutes of exposure to the air for some species (for others the water just has to get too warm, or too cold), the "skeleton" is already effectively a fossil and pretty well as hard as it's going to get.

Any reef is largely made of Limestone from dead Corals that have either simply been grown over or have been broken, ground down and then the coral sand concreted together because of biological and/or chemical processes to form bulk Limestone in which most or all of the old coralline structure is invisible. The primary mechanism for removing coral structure is actually fish that crush coral chips into sand or even finer grains while feeding on surface dwelling algae. The hardening of these grains into a homogeneous whole is usually a combination of the action of coralline algae creating lime on the grain surfaces that bridges individual grains together and the chemical precipitation of dissolved minerals, particularly calcium carbonate from the grains themselves, into the lime sand beds due to daily fluctuations in water temperature and the associated calcium carbonate solubility shift. As the temperature of the water drops at night more lime can and is dissolved into the sea, during the day this process is reversed by the rising water temperature. This process is ongoing with coral sourced lime being added to the limestone reef steadily all the time it's growing.

In terms of the grey colouration you've observed a lot of that will be land derived sediment that was incorporated into the reef while it was still growing and is the natural colour I would expect from an exposed reef deposit so close to shore. Some of it may also be surface in nature though and the rate at which that will accumulate will depend on the wind, the amount of dust in the environment and the surface porosity of the exposed deposit. The higher the winds, the dust count, and/or the surface porosity the faster that surface will be discoloured by dust. There might be a little bit of chemical staining from water percolation but that's normally in the form of Iron and is yellow, red, or orange in colour, similar to this image from Spain.

Short version not much has actually happened to the reef deposits you're seeing since they were laid down except that as the land has risen they've been taken along for the ride and are now above sea level.

If I missed anything or wasn't clear somewhere along the line give me a shout in the comments and I'll update accordingly.


depths of our planet

How deep? "Deep" is a relative thing. You can have 10 kilometres deep, or 5000 kilometres deep.

Super high pressure at the center of it

It's not the pressure per se that's causing the heat, it was the process of getting to the pressure when the Earth's formed. Compression creates heat. That's easy to know - just touch a bicycle air pump after filling up. There's also the issue of gravitational potential energy converting into heat once Earth was accreted. The the pressure and heat are together the result of Earth's formation. It's not that pressure itself makes the heat.

Radioactive decay

According to what we know, the three modern heat producing elements (thorium, uranium and potassium) are actually concentrated in the mantle, with an even greater concentration in the crust, which is just the top few kilometres. It's still deep for us humans, but extremely shallow when compared to the core. There is still some debate on this (see the two other answers), but my own personal opinion is that it's safe to say there's very little U Th and K in the core.
Also read my very relevant answer on the World Building website:
https://worldbuilding.stackexchange.com/a/123951/39999


No, you've misunderstood it. There's lots of information you're missing. Every data point is information, and you've listed a tiny proportion of them.

Furthermore, 4-7 km/h and 11-16 km/h aren't frequencies at all, they're wind speeds. The distance from the centre gives you the frequency.

So the spike towards N means that North winds are much much more frequent than the NNW and NNE winds. There may be some protection in those directions such that the winds that would come from there, are actually getting channelled to come from the North instead. Or there's a particular time-of-day effect, or a recording artifact, or one of a dozen other explanations that only someone with more information about the site and the data collection could assess.

However, the fastest winds don't blow from that direction at all: they're all coming from the quadrant between S and W.


Red volcanic soils - what are the likely constituents?

tl;dr

If it's red, it's iron.
If it's soil, it probably has iron even if it's not red.
Therefore there's no point testing it for iron (in a simple way), because you can be confident it's there.

I'd like to add a bit to Jezibelle's answer. First of all, you could do a simple chemical test to test for iron, but that would not give you much. Iron oxides on the surface are extremely insoluble in water. You would either have to use LOTS of soil and water to test it, or use acids that will dissolve it and then it's not a simple test anymore.

Another reason is that assuming you do that test, it is going to be positive for iron. Andesite has iron in it. This and just about every other rock you can find have iron in it. Those that don't, are not red. The colour that you're seeing is enough proof that there's iron in it.

Now the question is which iron oxide is it. Pure hematite ($\ce{Fe2O3}$) is deep dark red. Pure goethite ($\ce{FeO(OH).H2O}$) is yellow. But then you have everything in between, and mixtures (given the general name: limonite). Now remember, iron is not the only constituent of soil. Silicon is the most abundant metal in soils, followed by aluminum, sodium, calcium, magnesium and potassium (not necessarily in that order). These elements can combine with iron to form stuff that doesn't even have to be red. It can be grey, black, green and everything in between.


@John has answered to the second question: "Is there a natural process which removes salt from the sea at a significant rate?" This is an answer to the first one: "Is there a natural limit to this process, or the will the sea keep getting saltier forever?"
Yes, there is a limit, sea water cannot keep getting saltier forever.
Sea water is a solution of water and salt, i.e., the salt is dissolved in the water. But solubility, the ability of a material to dissolve in another, has a limit called saturation. Once this limit is reached, the material cannot dissolve anymore and precipitate.
Saturation of salt in water is 357 g L$^{-1}$ (at 20 °C, it depends on temperature), about 10 times the current salinity of seawater. If you keep adding more salt to such water, it will not longer be able to dissolve but will instead precipitate at the bottom of the sea.


What are the properties of the back arc extension related volcanic rocks?

Back arc basin lavas are basaltic and similar to the magma from mid ocean ridges, except that the magma from back arc basins is about four times as rich in magmatic water, which is typically 1.5 percent by weight of the rock.


What is the 'natural variation' in global temperature that climate-change skeptics mention?

First off, let me preface this answer with a disclaimer: I do not deny climate change.

From what I've read, the skeptics for the most part don't claim to have an alternative explanation for the recent warming. Their arguments (not mine!) are fourfold:

The recent warming doesn't exist, is natural, or is just noise. The tiny half degree warming we've seen in the last 40 years is a tiny blip on the huge changes that have occurred in the past.
Climate change is a natural occurrence. The climate has changed historically naturally by huge amounts, much bigger than the tiny half degree warming we've seen in the last 40 years.
Predicting the weather after ten days is a fool's errand. Predicting climate is worse than a fool's errand. It can't be done.
Even if things have warmed up in the last forty years, one thing is certain: It's not CO2. That a tiny trace gas could possibly drive the climate is laughable.

Those are not my arguments.

With regard to point #1,

Source: World Meteorological Organization Press Release No. 976: 2001-2010, A Decade of Climate Extremes

The above image speaks for itself. The global temperature change over the last forty years is very real, and is not noise.

With regard to point #2, yes the climate has changed in the past, and by huge amounts. We've had everything from snowball Earth to dinosaurs roaming the Arctic. And the point is? This argument is akin to a farmer taking a trip to the Grand Canyon and upon seeing what damage nature can do decides to forgo contour plowing and other anti-erosion farming techniques.

That the farmer's field might turn into a mountain or be washed out to sea several millions of years from now is irrelevant. What's relevant is that his good or bad practices have an impact on the world food supply. That nature can do far worse does not negate those bad farming practices. Bad farming practices are bad for humanity.

Getting back to climate change, if higher global temperatures are bad for humanity, it doesn't matter matter one bit how close ice came to the equator or how far north dinosaurs roamed in the past. What matters is that modern humanity is sensitive to climate change, be it natural or induced by humans.

With regard to point #3, yes, weather becomes chaotic after ten days or so. That does not mean that climate is chaotic, and if it is, the ~ten day Lyapunov time of the weather does not mean that climate also has a ten day Lyapunov time.

With regard to point #4, it is CO2. It was amusing to follow the skeptic response to Richard Muller's Berkeley Earth Surface Temperature project. Muller was a self-proclaimed skeptic, and he was going to prove those leftist climatologists wrong. The skeptic community cheered at the start.
"He's going to prove them wrong!" A funny thing happened on the way to proving them wrong: He proved them to be correct. Muller was an honest scientist in this regard. His own work caused him to switch from being a skeptic to ascribing to AGW.


How to genetically classify a mineral resulted from weathering?

My understanding of supergene is that it is about mineral enrichment/concentration at the base of an oxidized zone, within a weathered profile. The seasonal/periodic rise and fall of the local water table is critical to supergene enrichment.

  The descending meteoric waters oxidize the primary (hypogene) sulfide ore minerals and redistribute the metallic ore elements. Supergene enrichment occurs at the base of the oxidized portion of an ore deposit.

Supergene would not apply to the top of a weathered zone but to the base.

My old geology dictionary (The Penguin Dictionary of Geology, 1979) describes supergene as:

  A word suggesting an origin literally 'from above'. It is used almost
  exclusively for processes involving water, with or without dissolved
  material, percolating down from the surface. Typical supergene
  processes are solution, hydration, oxidation, deposition from
  solution, reactions of ions in solution with ions in existing minerals.

To me, supergene has a specific meaning, it may be part of the weathering process in some locations, but weathering involves the breaking down of rocks due to: reactions with atmospheric gasses, water (usually rain), changes brought on by plants, bacteria wind and temperature.

My suggestion to use the term weathering or weathered.


What is the lowest latitude at which snow has been recorded at sea level?

According to the USA Today article Answers archive: Winter, snow, ice, the sea level snow closest to the equator in recorded history are as follows.

The record for either hemisphere was in 1654, in the Chinese city of Nanning (now near present day Beihai) recorded snow, it is situated at 21°29'N.  This cold period is included in the article Coherence of climatic reconstruction from historical
documents in China by different studies (Ge et al. 2008) as part of a historical document that stated:

  ‘The winter in the 11th year of Shunzhi (1654 A.D.) was
  severely cold

For reference, the USA Today article states that the Southern Hemisphere record was considerably further from the equator, occurring in Valparaiso, Chile (33°02'S) in 1977.

One major caveat to this answer (asides from the USAToday source) is the length of time that records have been kept - for China, it has been thousands of years - there is virtually no equivalent record keeping in many areas (particularly in the Southern Hemisphere) for that length of time.

Having said that, according to the Australian Bureau of Meteorology, snow has been recorded in the 1950's and 1960's, several hundred kilometres north of Brisbane, the furthest north was in the Clark Ranges, west of Mackay at a latitude of about 21°S- but these locations were considerably higher than sea level, so do not qualify.

From personal experience, I recall when I lived in the southern suburbs (at sea level) of Melbourne as a child, one winter there was snow - melted as it hit the ground - but that is at a latitude of 38.2°S

In geological history, it could be argued that snow may have preceded the glaciation at the equator during Snowball Earth events, if proven to be true.


What is the range of possible atmospheric pressures on the surface of the Earth?

Presssure at the Mt. Everest summit has been measured to be 253 Torr (337 hPa).  http://jap.physiology.org/content/86/3/1062

Pressure at the Dead Sea as high as 1079 hPa is reported in Fig. 12 of this reference: http://isramar.ocean.org.il/isramar2009/DeadSea/Hecht&Gertman_2003_DS_Climate_Chapter4.pdf

As far as at sea level, 870 hPa was measured for typhoon Tip in 1979. http://www.wunderground.com/blog/weatherhistorian/world-and-us-lowest-barometric-pressure-records

And 1067 hPa at coastal areas of Estonia and Lativa are reported here: http://www.wunderground.com/blog/weatherhistorian/world-and-us-anticyclonic-high-barometric-pressure-records


What type of mammal does this fossil tooth belong to?

It's an entelodont, South Dakota is famous for it's Oligocene mammalian faunas which include entelodonts such as Archaeotherium and Daeodon.

here is an http://i.ebayimg.com/images/i/181202162847-0-1/s-l1000.jpg for comparison:

Thanks to the guys at fossilforum, they knew in less than a day. this question could have stayed on here for a year so i was impatient.


Did the surfaces of the oceans freeze over entirely during the snowball Earth periods?

By looking at the recent literature on the question, I see neither a consensus or a definitive answer on the extent of the snowball earth.

Since the Neoproterozoic Snowball Earth event is more recent, there seem to be more evidences available and therefore more relevant research on this event than the 2.1 BY one - and will consider in the following only the latest event.

This paper suggest that the ice cover was likely global but some open water would have persisted in equatorial regions where complex life would have been able to survive during the glaciation.

This other paper suggest that glaciogenic sequences (sedimentary rocks containing  sediments deposited by glacier actions, for modern analog non-consolidated examples see till or moraine) in high latitudes (North) contains fragments of carbonates which was likely formed near the equatorial zone and somewhat transported by glacier action.

This yet another paper modeled how glaciation likely reach the equator, where this paper suggest that open sea must exists.

Other papers suggested that once a significant part of the Earth was covered by glaciers, albedo effect significantly cooled the planet until some kind of massive volcanic eruption interrupted the cycle.

The only consensus I figure is that it most likely happened (a late Proterozoic Snowball Earth Event) but it still remain to be seen if a thick cover of ice 'a la Encalade' covered the Earth at one time or another, or not.


Glaciology: odd pattern of smooth and ribbed chunks of ice in Antartica

What you see are ice bergs frozen into a sheet of sea ice. The "chunks" are the ice bergs. Ice shelves are fed by two sources, ice from the interior of the ice sheet and ice formed by compaction of snow accumulating on the shelf itself. This means that a shelf can have very different dynamic regimes. Parts of shelves where ice is mostly formed locally will tend to be smooth whereas shelves feed by ice discharging from the interior can exhibit crevassing. It is very common to have ice streams or more rapidly flowing sectors carrying ice from the interior to the shelf and the position and width of these are often determined by subglacial topography (valleys and ridges where larger flow occurs in the valleys). At the margins of such more rapid sectors velocities drop from maybe hundreds of meters per year to a few or tens of meters per year. This cases severe shearing resulting in formation of cracks/crevasses.

When the ice eventually calves into the ocean as ice bergs, the ice will exhibit different patterns depending from what sectors it originates. The crevassed parts will result in the "ridged" features you see. Essentially, the ridges and furrows are traces of crevasse patterns. In your mid-picture you also see the calving front on the right hand side and it is evident that the ice there is heavily crevassed. It also exhibits flow striping (stripes in the direction of flow, usually perpendicular to the ice front) which indicates rapid flow.


Slab-breakoff - always connected to continent/continent collision?

Slab break off happens also during arc volcanic-continent collisions.
Andes is not an exception.


What is the status of meteorological data exchange standards?

I don't think there can be "the single standard" for a range of technical and organisational reasons.

Probably the biggest thing to note is that different formats serve different purposes. For example, comparing WFS, WMS and WCS. WFS is a feature concept - the sort of data you might get as observations from a set of irregularly distributed sites (e.g. automated weather stations at airports).  WMS is a picture (e.g. PNG image or JPEG) - the sort of data you might get as an IR image from a satellite, or some particular styling of a gridded forecast such as wave heights (turned into colour bands). WCS is a coverage (so no particular visual representation) - in the gridded forecast of wave heights example, it would be a floating point number of the height (average, peak, whatever is defined) for that "grid area".

Note that these OGC protocols weren't really designed to handle multiple parameters at a time, nor were they designed to handle data represented in more than two dimensions at a time (e.g. you can ask for an elevation and a time, but you can't ask for multiple elevations and times in a single output without some custom (i.e. not standard) approach.

So you'll see observations and forecasts in specialist formats (like BUFR, GRIB and NetCDF). Those formats can be transmitted (e.g. raw files), but they're also able to be subsetted. THREDDS is a particularly good tool for this purpose. Note that GRIB and NetCDF have some overlap in scope. There are also multiple versions of GRIB, and there are non-standard parts to GRIB (e.g. forecast centre specific tables). Adding new standards doesn't help.

Changing formats isn't easy - there are often massive collections of data and complex tools (like numerical forecasting models) that need to be updated or reworked to handle new formats. Not everyone can do that (e.g. for financial reasons, or organisational expertise reasons, or some programmatic reason like there is already another upgrade going on) at the same time.

So you can expect to need to handle lots of formats for a long time to come.

If you have options and need to exchange data, I'd start with NetCDF, mainly because it has a lot of pretty good tools.


What might be causing this rainbow-like effect on the ground?

This is very unusual and I've never seen it before, though I have seen other rainbow effects such as double and triple rainbows. What they all have in common is a mist of water droplets lit up by the sun. If you have ever seen a dew drop (and who hasn't) you will have noticed that when the sunlight struck it a pretty coloured light came from it. When you moved your head a little, the light changed colour. This is because white light is bent by the water droplet, and the different wavelengths bend to different degrees, so which colour you see depends on the angle of your eye to the dew drop. It's the same with a rainbow, but in this case there are millions of water droplets. It is also the case with the rainbow-like phenomenon in your photo, but instead of being high in the sky, the water droplets are hugging the ground.

So how could this happen? One possibility that occurs to me is that rain fell on hot ground, and quickly evaporated. As it evaporated into cold air, it condensed into water droplets, so you had this fine aerosol hanging low over the ground. Struck by sunlight, the white light was diffracted in the same way as in a rainbow or a dewdrop or the mist from a garden hose.


How global was the Bonarelli Oceanic Anoxic Event?

Recent research and models, based on sulphur and carbon radioisotope data, reported in the article Sulfur isotopes track the global extent and dynamics of euxinia during Cretaceous Oceanic Anoxic Event 2 (Owens et al. 2013) suggest that the oxygen-free and hydrogen sulfide-rich waters extended across roughly 5% of the global ocean, compared to <<1% today.

Owens et al. model results place important controls on local conditions, rather than global conditions and point to the difficulty in sustaining whole-ocean euxinia.

The models based on the sulphur and carbon isotopes suggest that

  the excursions were driven by increased burial of pyrite and OC. Although generally coupled, these C- and S-isotope excursions show a pronounced offset between peak magnitudes. The observed offset between these isotope signatures may not be unique in the geologic record but is certainly a pronounced characteristic of OAE 2.

and crucially, in terms of local over global controls,

  The spatial variability in the excursion magnitudes could be due to local watermass differences and/or varying riverine fluxes to an ocean with substantially lower than modern sulfate concentrations, an effect noted also for the Toarcian OAE*

Further explanations are provided in the article Marine $\mathrm{^{187}Os/^{188}Os}$ isotope stratigraphy reveals the interaction
of volcanism and ocean circulation during Oceanic Anoxic Event 2 (du Vivier et al. 2014), who found that, through analysis of marine $\mathrm{^{187}Os/^{188}Os}$ isotope stratigraphy

  differential input of nutrients from continental and volcanogenic
  sources, coupled with efficient palaeocirculation of the global ocean and epeiric seas, enhanced
  productivity due to higher nutrient availability, which permitted penecontemporaneous transport of
  continental and LIP-derived nutrients to trans-equatorial basins.

LIP = Large Igneous Provinces

and that the tipping point was rising sea levels at the time, further, the authors suggest that from local sources and igneous activity, coupled with rising sea levels and palaeo-oceanic circulation at the time, concluding with the evidence suggesting a global reach of the anoxic event:

  The close similarity of $\mathrm{Os_i}$ profiles from ∼50 kyr prior to the OAE 2 and through out the syn-OAE 2 interval indicates that transgression progressed to a point where a homogeneous global seawater signal was delivered to  multiple proto-transatlantic basins by active ocean circulation.

This suggests that the anoxic event started locally with weathering from the land surface, coupled with large igneous province (LIP) activity, progressing due to rising sea levels and palaeo-oceanic circulation.

Additional references

*Newton et al. 2013, Low marine sulfate concentrations and the isolation of the European epicontinental sea during the Early Jurassic


Unrealistic solution for advection-diffusion-reaction PDE with heterogeneous porous media

It's not clear exactly what is being modelled here, but it seems to me that there are two ways in which the concentration can 'go negative'. Firstly, the rate of change of concentration can be massive, in which case see what happens when modelling with much smaller time steps. Or, the diffusion term substantially exceeds the advection term, which is physically unlikely. However, you are modelling a large (more than 10-fold) anisotropy, in which almost all the flow will be in the x, horizontal direction - it is almost a one-dimensional problem in fact. So how can the advection be less than the diffusion? In the case of a constant concentration source, such as a saline water body, the negative results don't make sense, in which case the calculations have gone unstable, probably from using too large a time step. In the case of a pulsed source, as the concentration peak passes (along the x direction), the advected concentration rises and falls, such that the lateral (y axis) diffusion increases, then decreases, i.e. the concentration gradient changes direction, becoming negative.

As if this wasn't hard enough, in real life applications the 'sink' terms probably far exceed any back-diffusive effects.


Why doesn't it snow even when it is below freezing?

Farrenthorpe is right, a little surfing the net for snow distribution would clarify the picture for you. However, I think you are referring to certain times when it rains further north and snows further south. There are several reasons for local anomalies, of which the most important is the dynamics of the polar jet streams. These are strong high-altitude wind that blow constantly in both hemispheres. These winds have meanders which migrate around the world, as depicted in:

https://www.google.com/search?q=jet+stream++image+OR+picture+OR+diagram&lr=&as_qdr=all&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwiX44v3tbHJAhUEjywKHSncCP4Q7AkINA&biw=1352&bih=631#imgrc=LXFiBx8qaJg5xM%3A

Meanders in these polar jets pretty much control the mid- to high latitude weather within the troposphere, bringing bulges of Arctic air south, and counter bulges of warm mid-latitude air to further north. But then they move on, and the reverse conditions sometimes prevail. As a long-term average the latitudinal control on snow distribution dominates. Of course, there are other influences as well, mainly related to heat re-distribution by the great ocean currents.


By how much can rain temperature vary from the ground-level air temperature?

Rain is slightly cooler than near-surface temperatures because it condenses at higher altitudes where the air is colder. Thus rain tends to reduce the temperature difference between the surface and higher altitudes. This temperature difference is the free-energy or exergy source that ultimately drives convective weather systems and storms, and is expended or diminished by their operation. Usually the temperature of rain is only a few degrees cooler than that of ambient air by the time it falls to the surface. An extreme example is hail --- because of the large size and rapid fall of hailstones they can reach the surface still frozen even in midsummer. By contrast, freezing rain is often a different phenomenon. Freezing rain often results when rain originating in a warm air mass aloft falls through a subfreezing air mass near the surface, as typically occurs ahead of an advancing warm front.


Satellite ocean near-surface air temperature data

This is not a definitive answer but a few points from someone who has spent some time with remotely sensed temperature data.

I guess your best bet to get high spatial and temporal resolution surface air temperature would be to get reanalysis data from weather models and augment it with weather data from ships.

Purely satellite retrievals of surface air temperature are not very reliable as this is a rather indirect measurement. Consider Level 2 AIRS 50 km (approx. 0.5 deg) Surface Air Temperature data layer (https://disc.gsfc.nasa.gov/datasets/AIRS2RET_V006/summary?keywords=airs%20version%206). The spatial resolution is much lower compared to surface radiative temperature products. This is in order to compensate for the uncertainty in the atmospheric state and for lower resolution of the sensor that needs to balance its very high spectral resolution with lower spatial resolution to achieve usable SNR levels in each spectral channel.

Speaking of the reanalysis data the NCEP Global Data Assimilation System has 1 deg (approx. 100 km) spatial resolution. However depending on the region of study you might get higher resolution from regional weather models provided by local meteorologists. So you could start with the NCEP data spatially interpolated from 1 deg to 0.01 deg as an initial approximation.


Explanation for single rainbow that contained colors several times

It a supernumerary bow, which results when the droplets that create the rainbow are very small and of nearly uniform size. The droplets need to be small enough so as to make diffraction a significant effect.


Why is thunder and lightning rare, even though it rains frequently?

Rain in a climate such as Ireland is most often stratiform. That is, it is created when moist air is lifted by a front, or by divergence in the upper troposphere. Thunderstorms involve buoyant air, which rises on its own due to its being warmer than its surroundings. Typically solar radiation is involved in heating the surface such that the air near it warms and becomes buoyant. That is more common in lower latitudes and locations that are typically sunny.


Why does halite have perfect cleavage at the (110) plane?

I think the commenters have identified the issue. Halite does not have perfect cleavage along the {110} plane. As recorded in Mindat, Halite has perfect cleavage alone {100}, {010}, and {001}. This makes sense, as Halite is a cubic mineral (fcc), these are the planes you would expect it to cleave on.


What's the default meaning of "Valid" in NOAA weather map?

Short answer: Valid just means the expected conditions at that certain time.

In your example the map shows a forecast of 00 hours which is valid for 0600 UTC. Basically it means that the forecast/simulation is initialized on 0600 UTC and because the forecast time is 00 hours this forecast is also valid for 0600 UTC.

NOAA also provides forecasts for several hours (or days depending on the product). In this case, your simulation may be initialized on 0600 UTC but if you want to see what the conditions on 1500 UTC are you have a forecast of 09 hours which is valid for 1500 UTC. See this example.


Those charged particles you mention are not created by any kind of interaction with the Earth, but rather the term solar storm is used to refer to the temporary disturbance of Earth's magnetic field caused by bombardment of the charged particles which originate from the Sun. The stream of particles flow outward from the sun through the solar system(The particles escape from the sun because its outer atmosphere is very hot, and the atoms there move too rapidly for the sun's gravity to hold onto them).

However, these charged particles are different to the usual  solar radiation (visible and ultraviolet light) that penetrates Earth’s atmosphere and warms the surface. Most of the charged particles that are aimed at the Earth are deflected back into space by Earth's magnetic field, although a small amount may enter the thermosphere (upper atmosphere). This may cause some warming in the thermosphere, however, carbon dioxide and nitrogen oxide, coolants in the thermosphere, absorb the energy and then re-radiate heat back into space.  A small fraction of the extra heat from the solar flare radiates to layers of the atmosphere below the thermosphere, but it is insignificant compared to the normal amount of heating the lower layers of the atmosphere already experience from normal solar radiation.

References:

Bates, D.R., 1969. PHYSICS OF THE UPPER ATMOSPHERE. QUEEN'S UNIV BELFAST (NORTHERN IRELAND) DEPT OF APPLIED MATHEMATICS AND THEORETICAL PHYSICS.

Mlynczak, M.G., Martin‐Torres, F.J., Crowley, G., Kratz, D.P., Funke, B., Lu, G., Lopez‐Puertas, M., Russell, J.M., Kozyra, J., Mertens, C. and Sharma, R., 2005. Energy transport in the thermosphere during the solar storms of April 2002. Journal of Geophysical Research: Space Physics, 110(A12).


How is Doppler radar used in rain prediction?

The easiest answer is that Safe Haven is a movie, and the writer made a factual error (which is not uncommon). I have not watched that movie, so I am unsure what type of situation they were dealing with. Doppler radars do not predict, but they observe.

What is possible, however, is extrapolation and the creation of inferences. For example, tornadoes are not directly predicted by Doppler Radar, but by making inferences from the data, a meteorologist may detect a tornado. In a similar sense, if the radar-derived 'storm total precipitation' has estimated an average 0.25 inches of rain from a squall line for the past 200 miles, one may extrapolate, or estimate, that the squall line will produce ~0.25 inches of rain. Could the squall line alter its path or intensity and drastically change the amount? Sure, but without additional information, including information not derived from a radar, that would be a difficult task.

Edit: Ok, I think I have a better idea of what the question was and how it can be answered.
Doppler radar can measure wind speed relative to the radar site. So if can sense how fast a storm is approaching. Assuming the storm does not change it's speed, and given it's history, you can infer when it will arrive at the radar site. For example, if a storm is 50 miles away, and it moves at 25 miles per hour it will arrive in $50\text{ mi}\div 25\frac{\text{mi}}{\text{hr}}=2\text{ hr}$, provided the storm does not change.


Why is Carbon Dioxide a Greenhouse Gas whereas Ammonia is not?

A molecular gas is a good infrared absorber if it has several atoms (not just 2, like O2 and N2) or if it is hetero-nuclear (e.g. CO and NO).  These type of molecular arrangements allow more infrared energy to be absorbed because there are more vibrational states that are possible.  Yes, ammonia fits that description, but it is not long-lived in the atmosphere and it is not widespread.  So, even though ammonia is a good infrared absorber, it is not an important greenhouse gas.

Ammonia in the atmosphere is very reactive, and will form to make nitrates and sulfates while in solution (e.g. in cloud droplets).  Thus, the atmospheric lifetime of ammonia is short-lived, whereas most important greenhouse gases are long-lived and not reactive.  For global  warming discussion, you would likely associate ammonia with a net cooling effect since the increased formation of particulate (clouds/haze) increases the albedo of the Earth (which scatters light back to space).


What is cluster situation with respect to sand mining?

Cluster in this situation refers to a grouping or a number of mining operations within a giving area.

Sometimes deposits of minerals with sand deposits is such that a number of smaller deposits is created instead of one larger more continuous deposit. When this happens it sometimes makes more sense to mine the deposits as separate pits instead of one large pit. The result is a cluster of mines within a given region/area.


could a rhyolitic magma melt a ferromagnesian mineral like olivine?

This is an excellent question.

What does happen when you drop a crystal of olivine into liquid rhyolite?

There are several answers which all depend on the exact composition of the olivine, how much magnesium is in the rhyolite, temperature, size of the olivine, how much olivine are you dropping into how much rhyolite, and more.

Let's take the most extreme case of dropping pure Mg olivine (forsterite) into pure felsic rhyolite (a feldspar–quartz liquid mixture). For argument's sake let's assume full thermodynamic equilibrium.

First, rhyolites can dissolve some amount of Mg. Not much. Maybe 1%, maybe 2%. If it's only a tiny bit of olivine, the olivine will dissolve as a liquid into the rhyolite (you might call it "melt", but that's not the correct term), making the rhyolite a bit more magnesian.

If you add a bit more olivine, you saturate the melt with Mg. This means that a certain magnesian mineral will form in equilibrium with the rhyolite liquid. This could be biotite, amphibole, a clinopyroxene, etc. But because our simple system has no water and no calcium, pure solid olivine sounds like a good choice.

However, forsterite is not stable in felsic systems. It will react according to the reaction:

$$\ce{Mg2SiO4 + SiO2 = 2MgSiO3}$$

This is the reaction of forsterite (Mg-olivine), reacting with quartz, to form enstatite (orthopyroxene). Therefore, your olivine doesn't melt. It converts to a different mineral: orthopyroxene!

This is well illustrated by the following phase diagram, coming from this website:

Some more related questions and answers:

Melting point of minerals

Why do felsic materials have lower melting points than mafic?


Is sterescope still used to do cartography with orthophotography?

I am working in an academic environment and I know these tools are still shown to undergrads along other modern photo-interpretation techniques.

Often, modern techniques are more straightforward and convenient. There is a wide coverage of decent, recent and cheap satellite images available, providing a lot to work with in a short amount of time, easily compared to the interpretation of orthophotos. Elevation models, multi-bands and high resolution are big plus for modern techniques in a GIS for instance. Not counting just bringing a drone and ortho-photograph everything.

Where available stereo-pairs are somewhat older (50's to 80's) and of a limited/specific coverage depending on the region of interest - so this need to be considered.

But I also use stereo-pairs when I go in a tent at the tip of the globe where technology break, battery drains and internet lack. Portable stereoscope work well in the field.


Was volcanic activity more prevalent when the dinosaurs roamed?

There seems to be indeed reasons to believe in an enhanced volcanism during the Cretaceous at least.

The Cretaceous timescale is indeed peppered by the formation of large igneous provinces (known collectively as LIP; short review in Ogg & Hinnov 2012a): Parana at ca. 135Ma, the Ontong-Java Plateau at ca. 125Ma, the Kerguelen Plateau at 118Ma, the Caribbean Province at 90Ma and of course the famous Deccan Traps at the K/Pg boundary. In addition to those large events, they were as well other more minor pulses of large-scale volcanism during the earliest Cretaceous (Shatsky Rise), and at ca. 87Ma (Madagascar Traps) and ca. 73Ma (Sierra Leone Rise).

The 5 LIP, though localized to a specific region each time, had a global impact on the climate and on the oceans, as seen on $\delta ^{13}C$ curves for instance, or during the different episodes of Oceanic Anoxic Events.

As far as the pop culture trope is concerned, most of these volcanic events were partly underwater (Shatsky Rise, Sierra Leone Rise, Kerguelen Plateau, Ontong-Java) so I doubt dinosaurs were roaming around active volcanoes. It is probable that the trope originated instead in the idea that the Deccan Traps triggered the end Cretaceous mass extinction (i. e. the disparition of non-avian dinosaurs, in particular).

In comparison (see Ogg & Hinnov 2012b), there were only one LIP forming during the Jurassic in the Karoo Basin (South Africa); if we ignore the Central Atlantic Magmatic Province which formed just below the base of the Jurassic (it may or may not have caused the end-triassic mass extinction).

Ogg, J. G. & L. A. Hinnov, 2012a. Cretaceous. In F. Gradstein et al (Eds), The Geologic Time Scale 2012, Elsevier, Amsterdam: 793-853.
Ogg, J. G. & L. A. Hinnov, 2012b. Jurassic. In F. Gradstein et al (Eds), The Geologic Time Scale 2012, Elsevier, Amsterdam: 731-791.


What is the simplest meteorological model to operate?

I think you are asking a question with a variety of different constraints. I'll tackle a couple of them.

  What is the simplest atmospheric model to operate?

That would be the Zero-dimensional energy balance model. It has almost zero resolution and no temporal capacity.

  What is an atmospheric model that can be easily installed and run?

The Weather Research and Forecasting (WRF) model is a very flexible, limited area model. This model has successfully been run on what amounts to a child's toy.

  What is a global atmospheric model that can be run for a long period of time, but can easily be run?

While I have never run it myself, it sounds like you may be looking for SPEEDY. I have not heard it is the most numerically stable model, and I cannot attest to how easy it is to run. From the documentation, it seems like it can be run one year at a time, but I was once told that it is typically stable in the range of months or even days.

Atmospheric models are not like a game you can just install and run like MS Word or a game. With almost any atmospheric model, a knowledge of programming in a Linux/Unix framework is paramount.


Which crops are especially sensitive to atmospheric ozone?

I could find a relatively recent review by Mills et al. (2007) that lists sensitivity to ozone for several crops. Among the most sensitive were (table 1)

Watermelons (albeit with very few data points used)
Pulses
Cotton
Wheat

While the most resistant crops were

Barley
Fruits (Plums and Strawberries)
Broccoli

The measure for ozone used in this review is AOT40, which accounts for accumulated ozone levels over 40ppbV within the time from 8AM to 8PM.


Fair weather cumulus clouds are white because there is a clear path for sunlight to reflect off the cloud and into your eye.  Even when there are many of them, they are not vertically developed and photons can still scatter off of them to you.

As cumulus develop into towering cumulus and cumulonimbus they become horizontally widespread and quite high (the tops of severe convection overshoot into the stratosphere and the convection in the tropics can go even higher, owing to a higher tropopause).  A developed CB cloud also features an anvil.  These clouds are also optically thick, dense with cloudwater, rain, snow and ice.

For a cloud to appear white, photons representing the full visible spectrum must be able to arrive at your eye.  For an optically thick cloud of appreciable thickness, transmission isn't an option.  Note that both the physical thickness and the density of the cloud will increase its optical thickness.  This means that if the cloud size doesn't change but more and bigger rain drops are in the cloud, it will be optically thicker and appear darker. If there isn't a path from the sun to a surface of the cloud you can see, scattering isn't an option.  Water emits in the infrared, so emission isn't an option.  If visible photons cannot arrive at your eye from the cloud, then the cloud will appear dark.  The presence of hydrometeors (rain drops, snow, hail) in a rain cloud will further decrease transmission and darken the cloud.

Putting it together, as that white cumulus grows and becomes tens of thousands of feet tall, it will still appear white if the sun is on your side of the cloud.  It will appear darker if the sun is behind the cloud (transmission through the cloud).  As the cloud becomes horizontally thick, transmission will decrease, darkening the cloud if you aren't in a position to observe scattering.  Once an anvil starts to form, if you are anywhere near the storm you are likely in shadow and there probably isn't a path for scattering sun->cloud->eye.

In the picture you posted it appears the sun is behind the storm.  You can see the anvil in the upper left part of the image is bright white on its edge where you can see scattering from the sun.  As you see the anvil toward the storm it darkens because now you are seeing photons transmitted through the anvil, and less are making it to your eye.  The updraft is colored similarly, with some light areas with scattering and the bulk of the surface quite dark due to no scattering and low transmission.  Under the storm you see some bright clouds via scattering from the sun.  You can see this spectrum doesn't appear quite white, a consequence of different wavelengths scattering differently (and this effect can give rise to the green aura people associate with hail, which is really just related to having tall storms causing long path lengths and multiple scattering necessary for photons to reach your eye).


Why are the Little Colorado River and Havasu Creek blue?

The color of the water is determined by depth and mineral composition. Calcium carbonate is carried in the Little Colorado river water column and coats the river bottom. Calcium carbonate scatters white light (aka, looks white), so combined with water, which scatters blue light, a turquoise color is formed. When the water column is thin, white scattering of the calcium carbonate is more pronounced and the color of the water is lightened. In the deeper parts of the river, the color is a darker blue due to the smaller concentration of calcium carbonate (due to more volume of water) and the increased scattering of blue light through a thicker water column.

This blog has a great explanation.


Is it possible to determine where gold might be found based on a map, and if so, how?

On of the issues with geological maps is they have all required humans to walk over the ground and mark on a piece of paper the surface expressions of different types of rock and geological structures, such as faults and folds.

Because of this process and the time constraints placed on people when they mapped the land there will always be some level of detail missing.

Geological maps will show the different rock types and geological structures on the surface but they may not necessarily show what is at depth.

Geology has advanced to a state where most well trained geologist will know the potential for certain rock types to host certain type of mineral deposits, including gold. However, pinpointing where a gold deposit, or any other mineral deposit is located will always require a human to walk the ground and inspect it in more detail and to take samples and have them analyzed in a laboratory.

Initially those samples may be geochemical samples, others will be rock samples and chips taken from the surface or trenches dug into the surface, culminating in drill samples being taken.

To further assist where to look, geophysical testing methods may be used, such a magnetic anomaly testing or ground electrical resistivity testing.

It is very unlikely that anyone will be able to look at a geological map, and with any degree of certainty say "there is a gold deposit" or "there is a gold deposit that is economic to mine". More likely, a person will look at a geological map and say something like, "there is a greenstone belt, this may have potential to host a gold deposit, further investigation is needed".

There is an adage amongst some geologists that states "gold is where you find it". There is no altitude preferable for finding gold deposits. It's found in mountains, in deserts, in forests, under salt lakes, even dissolved in the oceans. The oceans contain the largest quantities of gold, but it is uneconomic to extract it from sea water because the concentration are so low.

Biological indicators, such a vegetation may work for some base metals, such as copper, but not necessarily for gold.

Also, gold can occur as a deposit of just gold, but it can also occur in association with other metals in the form of polymetallic deposits which contain gold, silver, copper, lead or zinc, even uranium.

Finally, not all deposits of minerals, gold included, are reserves. To be classified as a reserve and an orebody, a deposit of mineralization must be economic to mine.


Is there any rule of thumb to decide the indentation hardness test?

No. Grain size is not a factor . Test method depends on the size and shape of the test piece and why the test is being done. Vickers can use different loads so can be used for very small areas and the microscope can be used to select certain locations such as a carburized layer. Rockwell can test larger specific locations such as the components of a weld HAZ. Brinell hits a fairly large area ,it also requires significant thickness like 1/2 ". Vickers and Brinell results are based on the area of the impression , while Rockwell measures the depth of penetration. These comments apply to standard bench testers , portable testers is a different game.


How is Air Quality Index relevant to both PM2.5 and NO2

Most locations in the US don't see high concentrations of pollutants like NO2 and CO anymore.  They are largely no longer an air quality problem and air is "Good" in regards to those pollutants.  Especially during "lockdown", when traffic is light.  This is largely thanks to tailpipe emissions standards for vehicles and a much more fuel efficient fleet. On the other hand, PM2.5 has multiple sources that cause high concentrations, and we are much more likely to see the AQI vary beyond "Good" PM2.5 (e.g. outdoor fires, wood-stoves, secondary aerosol formation).

The AQI is based on health-based evidence, with a different concentration threshold for each pollutant.  These are all put onto the AQI scale for simple communication to the public. If concentrations of NO2 had reached levels of the NAAQS, then you would see your graph plot into those AQI levels (note NO2 doesn't go as far up in "AQI" values as PM2.5 on your graph because those NO2 concentrations were never detected by the monitor).

The National Ambient Air Quality Standard (NAAQS) for nitrogen dioxide (NO2) is a 1-hour NO2 standard of 100 parts per billion (ppb). See https://www3.epa.gov/airnow/no2.pdf and page 2 here: http://njaqinow.net/App_Files/2016/AQI%202016.pdf which has the break levels for each pollutant, shown below:


Generic pedo-transfer functions to compute field capacity and wilting point from sand/silt/clay?

As far as I know, there’s no one definitive pedo-transfer function (PTF) but there have been several studies that train functions against multi-site databases, rather than just deriving site-specific functions.  These PTFs typically define soil moisture-conductivity-suction relationships based on silt, sand and clay fractions from which you can read off field capacity (suction = -10 kPa) and wilting point (suction = -1500 kPa).  Which PTF you use will depend on the soil moisture-conductivity-suction hydraulic description that your model uses.

For Clapp and Hornberger hydraulics there's the Cosby et al (1984) PTF.  This is trained on data from the US.  It's quite possible that there are more recent PTFs trained on more and better data, but this one is still in use (e.g., by the UK Met Office).

For van Genuchten hydraulics there's the Wosten et al (1999) PTF (see also Wosten et al, 2001).  This is trained on the European HYPRES database, and you need organic percentage and bulk density in addition to the silt/sand/clay percentages.  There’s also ROSETTA (Schaap et al, 2001), which uses several PTFs hierarchically and is trained on data from North America and Europe.

Note that these hydraulic properties are difficult to measure in situ and in the lab, so the fitted PTFs often explain quite a low fraction of the variance in the training data.  You might be able to use this information to inform your priors, which should probably be quite conservative.


Why is the Atlantic anticyclone an area of high pressure if it's the warmest spot on the planet?

The Bermuda high is centered near the horse latitudes, where air from the tropical Hadley trade wind cell is sinking. This forced sinking of air can dynamically contribute to high pressure even if the air is warm --- warm air can be forced to sink against its own buoyancy in a Ferrel-type circulation. But the Bermuda high is helped thermally too, at least in summer, because the Atlantic Ocean at those latitudes, at least in summer, is cooler than North America and much cooler than the Sahara at the same latitudes. It is certainly easier for a Ferrel-type circulation to work against cooler surface temperatures than against warmer ones.


Roughly how much Co2 is generated per kWh of electricity generated

About 900 grammes of CO2 for each 1kWh of electricity.

There is some variation: very modern super-critical coal plants can be lower. But 900g is a reasonable central estimate.

Note that that's just CO2 from combustion. It can be higher, when we include CO2 and CH4 emissions from the rest of the coal supply chain too.


How high do you need to be to see Los Angeles from Washington DC?

The website you provide a link for gives the horizon distance as:

$d$ $\approx$ $1.23\sqrt{h}$

where d is in miles and h is height above ground level in feet.

Rearranging the equation

$h$ $\approx$ $(d/1.23)^2$

For a horizon distance of 2300 miles, the height would have to be 3,496,596 feet, or 662.2 miles.

For a flat Earth, it depends on the height of any obstacles between Washington DC & LA and the distance the obstacle is from either LA or Washington. If there are no obstacles, no height is required as light from LA can travel across the flat plane to Washington.

If you want to account for impedance provided by the Rocky Mountains, use Google Earth & draw a line between LA & Washington. A high point of around 9600 feet occurs some 780 miles from LA.

By using similar triangles such a height at Washington would be 28,308 feet.


700 m elevation difference on the windward side will be definitely enough to trigger orographic influences on precipitation. Thus from your description it seems very plausible that the mountains influence the precipitation you get.


About moving ice bergs northwards to slow down all the melting a tiny bit. ( Clearing away navigation hazards is a side effect of this.)

Some background. The idea of towing ice bergs to provide a source for fresh water in dry climate zones was first proposed in the 1970s by Weeks and Campbell (1973) and Hult and Ostrander (1973). This sparked interest that resulted in several studies published in conferences (Husseiny, 1980; IGS, 1980). The focus of the work was manly on the wastage of ice during transport and of course the technical aspects of towing ice. The main issue, however, concerns the integrity of ice bergs during transport. The mechanics of ice bergs is still poorly understood and it is known that bergs gradually break up. How this is affected by ocean swells and other forces acting upon a berg under tow is still investigated (see a wealth of publications in particularly Journal of Glacology and Annals of Glaciology). The idea has, however, not been forgotten and more possible technical solutions are proposed (e.g. Fast Company. So while the financial aspect of the process may be calculable, the strength of ice bergs, and the forces acting upon them in the open sea and under tow requires more research before towing could become a reality.

On top of this are legal issues. Who owns the ice? and also how can towing ice berg across busy shipping lines be safe, particularly in the event of a break-up in mid-ocean.

To respond to your specific question on towing northward and anchoring: The towing in any direction is subject to the same issues as described above. Anchoring, the ice bergs will melt and degrade over time so that moorings will continually have to be renewed. Most ice bergs in the north will go through at least one cycle of being caught in seasonal sea ice but eventually will be set free to follow ocean currents in whatever direction they move locally. Since the ocean water will carry some heat, it will not matter where the ice berg is located, it will slowly melt. On top of that is the issue of disintegration since melting will change the shape of the berg and hence its stability and centre of gravity causing stresses within the block to alter.

If one takes a longer-term perspective and ignores the practicalities (incl. costs), moving ice to a place where it melts slower would momentarily decrease the contribution but eventually one would reach a new equilibrium where the same rate of melt water will be contributed and the temporary benefit will be lost. So apart from being highly impractical from all aspects, the longer-term benefits will be nil.

References

Hult, J.L. and Ostrander, N.C., 1973. Antarctic icebergs as a global fresh water resource. Rand Corporation, Santa Monica. Report No. R-1255-NSF. 83 pp.

Husseiny, A.A. (ed.) 1978. Iceberg Utilization. Proceedings of the First International Conference, Ames, Iowa, 1977. Pergamon Press, New York. 759 pp.

IGS (International Glaciological Society), 1980. Proceedings of the Conference on the Use of Icebergs. Annals of Glaciology, 1 136 pp.

Weeks, W.F. and Campbell, W.J., 1973. Icebergs as a fresh-water source: an appraisal. Journal of Glaciology, 12, 65, 207-233.


Are we going to enter a mini ice age by 2030?

These claims originate with a paper by a mathematician named Valentina Zharkova and others, who studied a correlation between solar magnetic fields and sunspots.  Based on the last three solar cycles, her model predicted that the next several solar cycles will be less intense than typical (i.e. fewer sunspots), which implies lower radiant output.

Here is an article addressing the claims and explaining why it's not something to worry about.  Some key points include:

The paper only addresses solar activity, and does not mention the impact that lower solar radiation would have on earth.  Climate scientists have looked at the impact that a Maunder Minimum would have, and found that the cooling effect of reduced solar output is less than the warming effect of increased greenhouse gases, so the net effect is that the earth will continue to warm even if the predictions turn out to be correct.

The cooling associated with the Maunder Minimum was not entirely due to the lower sunspot numbers.  There is evidence that massive volcanic eruptions played a significant role in the cooling.

Claims that the earth is already cooling because there may be fewer sunspots 5 or 15 years from now simply make no sense, and  global temperature measurements  clearly show that there is not a cooling trend.


Did temperature for the US state of Illinois reach an all-time record low 1/31/2019?

The record is unlikely to change, at least based on the particular measurements provided in the initial question.

According to the Illinois State Climatologist Office at the link you provided, the -37°F temperature record was discarded for lack of quality assurance: "However, that observation came from a small airport station designed for aviation purposes and was not part of the climate network in Illinois. As a result, the data were not always archived and no quality control procedures were applied to the data."

From the URLs in your question, the recent weather observations you refer to exist within Weather Underground's network of personal weather stations. In other words, they are often relatively inexpensive sensors that are owned and maintained by private individuals, and their measurements will not have the accuracy required to be included in the official temperature records for the state. The actual temperature at the Sinnissippi Point station may or may not have been colder than Illinois' verified lowest temperature, but without additional info (e.g. knowledge of specific instruments/sites and operator, as implied in the answer by @DavePhD) the official record will not change based on that measurement.


What are the ranges of natural (or pre-industrial era) levels of CO2 in the atmosphere in ppm and tons?

There is no such thing as a single "natural" level of $CO_2$: In Earth's history, there have been levels much higher and much lower than currently, and they are all natural.

What we should consider instead is what levels of $CO_2$ are compatible with the mild and stable climate that humanity has enjoyed for the last few millennia, or conversely, which levels will upset the climatic equilibrium and send Earth into a completely new climatic regime.

The means to measure atmospheric $CO_2$ concentrations were invented during the industrial revolution, so we don't have direct records before that. However, we can reconstruct past $CO_2$ concentrations using proxies such as the analysis of air bubbles trapped deep within the ice in Antarctica.

Ice cores were drilled up to ~600 meters deep between 1987 to 1993 at Law Dome (Antarctica), allowing the reconstruction of $CO_2$ concentrations from the last millennium, and it looks like this:

Where the darker blue at the end corresponds to the direct instrumental record (source).

Later, another ice core from Vostok station in Antarctica was drilled to a depth of more than 3.6 km, allowing the reconstruction of atmospheric $CO_2$ concentration during the last 400,000 years, and it looks like this:

(Figure source)

The data from Law Dome and that of modern records at Mauna Loa, Hawaii are also displayed on the end for comparison.

More ice cores have been drilled after Vostok, and all of them tell more or less the same story.

So we know that atmospheric $CO_2$ concentrations now are much higher than at any other time since we invented agriculture. And the people that think they know how the atmosphere works run models and say that current levels will significantly upset the climate as we know it. On the other hand, the people who don't know how the atmosphere works (like me), should just stop producing so much $CO_2$, because we don't ourselves know what the effects could be, and at the same time, we rely on the climate to stay nice and stable to keep your flourishing society alive.

To address the last bit of the question, to transform 1 PPM by volume of atmospheric $CO_2$ into a GigaTon of Carbon you just have to multiply by  2.13. So the pre-industrial base level during the last millennia of 280 PPM is equivalent to ~596 GtC or 2,187 Gt of $CO_2$ (multiply again by 44/12, the ratio of $CO_2$ mass to C mass).