Isn't a warmer climate better for energy generation? Nowadays, everyone talks about it: climate change, and more importantly, how to stop it from happening. Although there's a lot of debate around the topic, the conscensus is that by inventing a way of generating clean energy, we can slow down (and maybe even reverse) the effects global warming has on the planet. Using energy that was created without burning millions of years worth of stored carbon, we can not only power our everyday lives, but also capture the carbon we've been blowing into our atmosphere using the energy-intensive process of carbon capture.

But there are still some problems. Currently, photovoltaic cells are pretty much useless during winter when it comes to fueling the homes of millions (at least where I live). We want to warm our homes, but there's not enough clean energy during those months, so we fall back on nuclear.

Wouldn't it therefore be better to have a small rise in global temperature? I mean, a higher temperature means you don't have to warm your home during winter (as much). During summer, you can use the extra energy generated by the photovoltaic cells to power airconditioners in order to cool buildings and (maybe) use some excess energy to stop the snowball effect that those higher temperatures would have on the climate and keep it at a constant level. Even though cooling requires more energy than heating, might it break even?

I don't have the knowledge nor the means to calculate if this is the case.

I know that climate change is a thing and that it's really, really bad. I'm not a guy that doesn't believe the effects it has on our surroundings. I just don't have the means to investigate this idea, that's why I ask you: will the rise in temperature have a positive effect on our energy production and the ability to satisfy energy demand?

The real problem, of course, is that it's not going to be limited to a small rise in temperature.

However, WRT energy generation in particular, most forms of generation become less efficient as temperature increases.  For thermoelectric generation - fossil fuel, nuclear, & geothermal - that's obvious thermodynamics.

Photovoltaic cell efficiency also decreases with increasing temperature (e.g. https://www.sciencedirect.com/science/article/pii/S1876610213000829 ).  The drop in energy production during winter is a product of factors like the shorter day and lower sun angle, not the temperature.

Unless I've missed something, that leaves just hydroelectric & wind generation.  AFAIK, they aren't directly affected by temperature.  Changes in weather patterns might produce more or less precipitation and stronger or weaker winds in any particular location, but I don't think the effects are predictable, or necessarily a net increase.

Finally, increased temperature affects the efficiency of power transmission.  Electrical resistance increases with temperature, so an increase in temperature leads to increased transmission losses, and a decrease in the effective capacity of the lines: https://iopscience.iop.org/article/10.1088/1748-9326/11/11/114008


Climatology of the Indian Summer Monsoon - A modern consensus Edmund Halley viewed the monsoon as a glorified sea breeze circulation fueled by different heat capacities of land and ocean.

The resulting meridional temperature gradient between warmer air of the land and cooler air of the ocean  fueled by heating caused by the Sun were thought to cause precipitation in the Indian subcontinent. However, there has been tremendous progress in recent times and a broad consensus has been reached on the climatology of the the Indian Summer Monsoon. Several groups of scientists are converging on the land - ocean - atmosphere coupling model as an explanation of the causes of the Indian Summer Monsoon.

What are the salient features of the new understanding of the land sea atmosphere coupling model?

The question does NOT refer to causes of the interannual variability of the Indian Summer Monsoon but the climatological causes of the Indian Summer Monsoon.

The Indian Summer Monsoon(ISM) has several layers of complexity as it involves interactions between land, sea and atmosphere. This answer will focus on the state of the art overall understanding of the ISM and provide a summary of the salient features of the interactions between land, sea and atmosphere. In general it should be noted that while some references may talk of Land - Atmosphere interactions and Ocean - Atmosphere interactions it is almost impossible to differentiate between the role of land - atmosphere interaction and that of the  ocean -atmosphere  separately and the two processes should be considered to be part of the overall land - atmosphere - ocean interaction especially in the context of Asian Summer Monsoon[1]

1) Seasonal transition from boreal spring to  summer causes heating of the Asian landmass faster than the  surrounding oceans owing to the difference in heat capacities in land and sea leading to the establishment of a meridional temperature gradient [2]. The land retains  a shorter climate "memory" than the ocean [1].

2) The presence of the Himalayas(oriented east west) and Tibetan plateau ensures that sensible heating occurs aloft as well. The implications of the elevated sensible heating are that not only is the meridional temperature gradient present at the surface but aloft as well and  thereby "tethering" the monsoon onset [2] [3]

3) Formation of a surface heat low pressure over the Indian subcontinent during the late boreal spring that ensures a cross equatorial flow due to the north south pressure gradient at the low level and return cross equatorial flow aloft.

4) Thermodynamic conditions caused by the solar heating in boreal spring and early summer cause the seasonal migration of the Inter Tropical Convergence Zone also known as the Monsoon Trough(MT) [4]

5) Seasonal migration of the Mascarene High from it's December January February(DJF) position over the south eastern Indian Ocean at 85 E 30 S to June July August(JJA) position over the southern Western Indian Ocean near 55 E 30 S[5]

6) The role of East African Highlands(oriented north-south) in blocking the low level easterly flow and steering the winds across the equator into the south westerly monsoon flow. Without orographic influence of the East African Highlands  the south easterly winds that blow across the equator would blow over East Africa and the Atlantic rather than being transformed into the Somali Jet[5]. A GCM simulation study in which the orographic influence of the African Highlands were removed showed  that the Highlands have a huge influence on the monsoonal flow[6]

7) The Findlater Jet otherwise known as the Somali Jet gathers momentum due to the Earth's rotation [7]

8) A wind evaporation feedback mechanism is responsible for rapid onset as well as intensification  [8]

9) Initial monsoon onset is attributed to sensible heating but after the monsoon has set it is latent heat that drives the monsoon.[9]

10) Interactions between extra tropical eddies and meridional overturning circulation modelled as feedback. This study is remarkable as it shows that the onset of monsoon can be modelled in the absence of surface in-homogeneities as well as hydrological cycle [10]

11) The poleward extent of the monsoonal precipitation has been attributed to the "ventilation effect". At mid latitudes westerly winds advect air with low moist static energy from the cool oceans of the continent which tends to balance incoming solar radiation [11] [12]

12) Oceans contribute by changing SSTs and the Indian Ocean sees a large surface positive heat flux during the boreal spring and summer which is balanced by net southward transport of heat across the equator and increase of heat storage across the upper ocean [13]

Finally it must be mentioned that not all of the coupled feedbacks have been fully explored in general circulation models or in observations [14]

References

[1] Yasunari, T. Role of Land - Atmosphere Interaction on Asian Monsoon climate. J.O.M. S. of Japan, Vol. 85 B, pp.55-75, 2007

[2] Li, C. F. & Yanai, M. The onset and interannual variability of the Asian summer monsoon in relation to land sea thermal contrast. J. Clim. 9, 358–375 (1996).

[3]Fasullo, J. & Webster, P. J. A hydrological definition of Indian monsoon onset and withdrawal. J. Clim. 16, 3200–3211 (2003).

[4]Prive, N. C. & Plumb, R. A. Monsoon dynamics with interactive forcing. Part I: Axisymmetric studies. J. Atmos. Sci. 64, 1417–1430 (2007).

[5]Slingo, J., Spencer, H., Hoskins, B., Berrisford, P. & Black, E. The meteorology of the western Indian Ocean, and the influence of the East African highlands. Phil. Trans. R. Soc. A 363, 25–42 (2005).

[6]Rodwell, M. J. & Hoskins, B. J. 1995 A model of the Asian Summer Monsoon. II. Crossequatorial flow and PV behavior. J. Atmos. Sci. 52, 1341–1356.

[7] Findlater, J. A major low-level air current near the Indian Ocean during northern summer: Interhemispheric transport of air in the lower troposphere over western Indian Ocean. Q. J. R. Meteorol. Soc. 96, 551–554 (1970).

[8] Boos, W. R. & Emanuel, K. A. Annual intensification of the Somali jet in a quasi-equilibrium framework: Observational composites. Q. J. R. Meteorol. Soc. 135, 319–335 (2009).

[9] Chou, C. Land-sea heating contrast in an idealized Asian summer monsoon. Clim. Dynam. 21, 11–25 (2003).

[10] Bordoni, S. & Schneider, T. Monsoons as eddy-mediated regime transitions of the tropical overturning circulation. Nature Geosci. 1, 515–519 (2008).

[11] Chou, C., Neelin, J. D. & Su, H. Ocean-atmosphere-land feedbacks in an idealized monsoon. Q. J. R. Meteorol. Soc. 127, 1869–1891 (2001)

[12] Chou, C. & Neelin, J. D. Mechanisms limiting the northward extent of the northern summer monsoons over North America, Asia, and Africa. J. Clim. 16, 406–425 (2003).

[13] Loschnigg, J. & Webster, P. J. A coupled ocean-atmosphere system of SST modulation for the Indian Ocean. J. Clim. 13, 3342–3360 (2000).

[14]Turner, A. G. and Annamalai, H.  Climate change and the South Asian summer monsoon. Nature Climate Change, 2. pp. 587-595.(2012)


What is more important in Antarctica calving or basal melting of the ice shelves? Ice shelves are present along 75% of Antarctica coast and cover over 1.5 million km2. The two main processes causing mass loss of the ice shelf are basal melting and calving. Which of the two processes is more important in Antarctica?

There are two studies published in 2013 that provide the most recent updates on this balance

Depoorter, M.A. and 6 others, 2013. Calving fluxes and basal melt rates of Antarctic ice shelves. Nature, 502, 89–92, (03 October 2013),  doi:10.1038/nature12567
Rignot, E. and 3 others, 2013. Ice-Shelf Melting Around Antarctica. Science, 341, 6143, 266-270, (19 July 2013), doi: 10.1126/science.1235798

The first study arrives at a calving loss of 1321 ± 144 Gt/yr year and a total basal mass balance of −1454 ± 174 Gt/yr (− = loss). The mass balance is the net of mass added by freeze on and mass lost by melting so the number does not reflect melting alone. The pure loss by melt is hence larger but from a balance perspective the net is what counts.
The second study indicates a calving flux of 1089 ± 139 Gt/yr and a basal melt of 1325 ± 235 Gt/yr. Although they report "melting" it is likely that they mean net balance as in the other study.
The two studies have used slightly different approaches to arrive at their results, both indirect, but over all the numbers indicate that basal losses are larger than calving and that the order of magnitude is the same.
In more detail, the studies show that calving losses are dominant from the larger ice shelves, the Ross and Filchner-Ronne. Melting dominate regions along the western Antarctic Peninsula and down along the coast of the Bellingshausen and Amundsen seas. For most of the East and West Indian Ocean coastlines losses are relatively small and equal between the two processes.
The bottom line is that these studies have changed the perspective from ice loss being predominantly through calving to now slightly dominated by basal melting.


Using the Born approximation in seismic inversion In physics, the Born approximation allows us to separate the wave-function in terms of electronic and nuclear components.

Why is this concept relevant in seismic inversion? For example in Colombi et al. (2014), Geophys. J. Int. (2014), doi 10.1093/gji/ggu112 .

The best reference on this is:

J.A. Hudson and J.R. Heritage, 1981, The use of the Born approximation in seismic scattering problems, Geophys. J. R. Astr. Soc., v.66, 221-240.

Basically, the Born approximation is a governing principle of the standard imaging condition that treats seismic wavefields from a single point scatterer. This is the justification for simplifying the full elastic wave equation into the scalar and vector potential wavefields and just working with the scalar wave equation for the purposes of building seismic images.

There is a very nice derivation of this in Aki & Richards (Quantitative Seismology, 1980).


Does the Sun's oscillation affect Earth's climate? Today, discourse on climate change seemingly tends to focus on earthly elements such as pollution and human activity. While I am certainly not well-read on climate change research, after inspiration from a physics teacher's example of a baseball bat's center of gravity, and from reading this Stack Exchange post, I was curious about how the Sun's oscillation might play into our planet's entire climate activity. Have scientists even considered this information in determining the cause of climate change? Due to its elliptical orbit, Earth's distance from the sun changes, but wouldn't the Sun's oscillation affect what parameters this distance shall be over time?

I'll get you started at least, this is a bit too broad otherwise; I guess what you're describing are called Milanković (Milankovitch) cycles. Are climatologists aware of these? Yes, for a long time. Milanković published his first paper on the subject, Theorie Mathematique des Phenomenes Thermiques produits par la Radiation Solaire, in 1920. As for Solar oscillations in general, even much longer periodicity of ~ 26 million years of the Sun's oscillation about the galactic plane has been considered before (in 1984). As we're aware of the 11 year solar cycles, and have been integrated into climate models that climatologists work with, including collective effects of all of these manifesting in grand minima and maxima of solar activity (PDF).


How much water gets consumed by residential use versus all other uses? I have read different statistics on residential water use. One EPA chart I saw had residential use of water taking up half of all water, which seems unbelievable to me. Another writer claimed that only 1% of water is used by residential consumers. Quite a big difference.

One statistic I saw said that 45% of water "withdrawals" was for thermoelectric power, but presumably water can still be used by other consumers after it has gone through a dam power plant.

If we split water use between (1) residential consumption, (2) agricultural irrigation, (3) industrial consumption, and (4) commercial business consumption, there would seem to be four basic types of consumers. What is the relative balance of water consumption between these four types?

Dams are hydroelectric, thermoelectric is something else.

Thermoelectric refers to water extracted to boil to power a generator or used to cool the fluid used in said generator, In the US mostly coal, gas, and fuel oil plants but other ones like geothermal, nuclear, and mass solar also count, basically if it works off heat it consumes water (thermo- literally means heat). Much of this water of course evaporates. And yes it is quite high. About the same as we extract for irrigation.

 https://water.usgs.gov/watuse/wuto.html

Public water (purple), can be further divided, the USGS estimates public use as follows. You'll note no differentiation is made between commercial and industrial.

Wikipedia actually has a decent entry with further EPA estimate breakdowns, if you want to dive further.


Is it natural for clouds to flow near the surface? A week ago, I have seen something that I have never seen before, Nah it's not a flying dragon, but clouds that were flowing so near my roof (about 5-6 meters above my roof). These are the pictures, I have taken

Some of the clouds were passing just above the tree. I just want to know if this is a natural scene that occurs very often. What's the reason for clouds to flow so close to the surface?

I suppose that it had been raining before. The water had gone to the soil, but the moment you took that picture, it was already evaporating. The air was filling with such water coming from the soil, but air can hold only a limited quantity of gas water, so no more water could be in the form of gas (at so called "point of saturation"). Thus, it changed its state of matter from gas to liquid. But as we all now, liquid water can be seen (the "gas" above the boiling water that we can see is actually liquid water that rapidly cools down). Also, clouds are just such liquid water caught in the air, thus a cloud formed.
The near surface clouds can also form near the sea, with orographic clouds, or on a front, but such near surface clouds are more similar to fog (actually they are fog).


Has a hurricane or cyclone ever reformed after passing over a large land mass? Hurricane Michael recently hit Florida as a Category 4 storm, and after the remnants passed across a great deal of the east coast of the United States it appears to have re-emerged into the Atlantic Ocean as a "tropical storm" with some models predicting it will cross the Atlantic and a couple even suggesting it will then turn south and possibly loop back west again. Unfortunately the model I saw predicting the full turn has been overwritten by a new forecast, so I can't put a link here but it is intriguing as a possibility.

Has any hurricane or other tropical storm ever managed to hit land deeply as Michael did, where most of the storm has been inland for more than a couple hundred miles, and then re-emerge over the same ocean and reform into a substantial storm in the same ocean?  If it struck two different land masses, did a whole loop across a basis hitting a second time close to the first area, or if regained most of or more than its former strength that would also be notable but not required.

This page mentions hurricanes that have crossed from one ocean to another but does not mention storms that have reformed in the same Ocean (with the Caribbean counting as part of the Atlantic).  One reason I'm not wanting to count these storms is that to cross between oceans like this requires a relatively small jump over land, especially if done across Central America, such that a significant part of the storm may always be close enough to water to fuel it, whereas Michael seems to have traveled at least 800 miles across land without much ocean support and is still being reported by multiple weather sources as being "tropical storm" strength and projected to possibly be a tropical storm all the way across the Atlantic, for instance in this forecast:

(This copy is here because this image is from this link and will likely be overwritten as soon as the next forecast is run.)

Since you don't seem interested in Atlantic-Pacific crossovers, of which there are several good examples.....

2004's Hurricane Ivan made landfall on the Gulf Coast, degraded into a tropical depression and was eventually declassified while crossing the southeast US. After coming back into the Atlantic, Ivan tracked back south, re-formed into a tropical depression, then hit the Atlantic coast of Louisiana.

The key was the southward track in the Atlantic. Hurricanes weaken when they're that far north; they're away from the warm ocean waters that generated them in the first place.  But because Ivan tracked south into warmer waters it was able to strengthen a little. It may have been pushed by a cold front. But also, the next hurricane, Jeanne, was already approaching Florida, so Ivan may have been sucked into the circulation around it. Jeanne did its own loop-de loop out the in the Atlantic, so the jet stream may have affected both.


Earth's interior heat ratio between pressure and atomic decay What is our current understanding between the ratio of Earth's interior heat between the downward pressure and atomic decay?

There is no heat caused by pressure. Heat increases with depth, like pressure, so the two show a correlation, but this does not imply causality.

The two main sources of Earth's internal heat are radiogenic heat (as you said) and primordial heat, that is the kinetic energy turned into thermal energy during the accretion of the planet. There are also minor sources, like tidal heat caused by the Moon, and latent heat caused by crystallization of the liquid core.

The total heat budget of the Earth is pretty well constrained: we can just measure the heat flow coming out at the surface (in W/m$^2$) and multiply this by the Earth's area. The current estimate is ~47 TW (Davies & Davies, 2010). Getting ratios between sources, however, is more difficult, and rely mostly on modelling. See for instance the work of Dye (2012), who proposed a radiogenic heating of 15–41 TW, while other authors (referenced by Dye) proposed 12–30 TW of primordial ("fossil") heat. As you can see, the uncertainty is still quite high...


What is the range of possible atmospheric pressures on the surface of the Earth? I'm developing an Android app which uses a pressure sensor. Due to storage limitations I have to normalize and scale the atmospheric pressure values. For this I need to know the extreme values of pressure.

Different conditions should be respected, e.g.

Weather conditions (low/high)
Locations (high mountains, deep valleys like Dead Sea with a surface elevation of: -427 m (−1,401 ft))

If this is unknown, does anybody know the range at sea level? Something like 1013 hPa ± X?

With a formula I've found I calculated that the pressure on Mount Everest should be something like 300 hPa and at Dead Sea about 53 hPa more than at sea level. But this is not a very complex formula, so these values might be theoretical and wrong.

Edit / additional info

I discovered that my sensor provides values like 980.01 hPa, so there are 2 digits precision (don't know whether this reflects sensor precision). A difference of 0.01 hPa means ~8cm altitude. This might sound little, but I need to calculate the current incline of athletes, so I cannot sacrifice precision. My current scaling algorithm produces normalized numbers from 0 to 32768. It would imply much work to change the output range.

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


Does this peer-reviewed study (referenced in Forbes) contradict the accepted position that climate change is real? This Forbes article from 2013 (archive link here) with the headline "Majority Of Scientists Skeptical Of Global Warming Crisis" gets brandied around a lot. It states that

  Only 36 percent of geoscientists and engineers believe that humans are
  creating a global warming crisis, according to a survey reported in
  the peer-reviewed Organization Studies. By contrast, a strong majority
  of the 1,077 respondents believe that nature is the primary cause of
  recent global warming and/or that future global warming will not be a
  very serious problem.

Also, 14% of the respondents replied that :

  “they strongly disagree that climate change poses any significant
  public risk and see no impact on their personal lives.”

The article is reporting the paper Lefsrud and Meyer (2012) "Science or Science Fiction? Professionals’ Discursive Construction of Climate Change", Organization Studies, 33(11), pp. 1477–1506.

I want to know if that article has been refuted anywhere, and (if the information is misleading), how can a layperson recognize that, given that its published in such a renowned magazine.

I want to know if that article has been refuted anywhere

Yes. You can read all about it in the blog post
James Taylor misinterprets study by 180 degrees.

In short, the original paper was designed to test the view of "professional geologists", which in this case are members of the Association of Professional Engineers and Geoscientists of Alberta. The vast majority of them work in the fossil fuel industry. Therefore, those are people whose livelihood depends on the extraction of fossils fuels. This is not exactly the most unbiased crowd...

The article by James Taylor is spinning the original study into claiming that it applies to all geoscientists. The original authors of the study actually replied to Taylor's article saying:

  First and foremost, our study is not a representative survey. Although
  our data set is large and diverse enough for our research questions,
  it cannot be used for generalizations such as “respondents believe …”
  or “scientists don’t believe …”

(This is taken from a secondary source here)

In short, the article is not from "Forbes" (i.e., presenting the opinion of Forbes magazine). It was published in Forbes, but written by a lying climate denier. He has misinterpreted the original study, as evident by two independent analyses and by the reply of the authors themselves.

So to answer your question:

  Does this peer-reviewed study contradict the accepted position that climate change is real?

This peer-reviewed study does not contradict anything. Climate change is overwhelmingly accepted by all scientists. What this peer-reviewed study shows is that those who deny the realities of climate change are those employed by the fossil fuel industry, particularly people in top management positions.

Also, quoting myself from the comments:

  The study correctly showed that people employed by the fossil fuel
  industry tend to disagree that climate change is anthropogenic. The
  Forbes article generalised this to all scientists. This is wrong. The
  authors of the study said this is wrong.

I will finish with some anecdotes. I am a geoscientist at a top Australian University. Every single one of the scientists here accept the climate change is a major threat to modern human civilisation as we know it. In a previous university where many people were involved with fossil fuel research, people accepted the realities of climate change. They were involved with the research because they either tried to find better ways of fossil fuels (realising that renewables are not there yet, and nuclear is unfortunately not an option), or because they have to pay their rent and feed their children. None denied that climate change is real, and none denied that the fossil fuel industry is the leading cause of it. We geoscientists all understand that the major driving force of the fossil fuel industry and climate change denialism is political, financial (usually old white rich men who don't care about anything but their own monetary benefit) and not scientific.


Growth of polar vortices vs projective geometry; what does this figure mean? I was reading the Wikipedia article about a mathematical subject called projective geometry, and I noticed that the second image in the body of the article referred to the "growth of polar vortices". The only use of the term polar vortex that I'm aware of is in meteorology:

  A polar vortex is an upper level low-pressure area lying near the Earth's pole.

Can anyone recognize how this drawing might relate in any way to meteorological polar vortices?

From the Wikipedia article Projective Geometry:

Caption: "Growth measure and the polar vortices. Based on the work of Lawrence Edwards"

I suspect that this diagram has nothing to do with polar vortices in the meteorological sense. It’s hard to prove a negative, but digging into the source of this image led me in some very non-meteorological directions.

The file itself is entitled ‘Growth measure and vortices’ on Wikimedia (note absence of ‘polar’), with a source of ‘own work’ (by the user ‘Snowy Weather’) and the description ‘Projective geometry block in a Waldorf high school’.

Apart from the ‘Projective geometry’ page, the only Wikipedia page using this image is the one on Waldorf education, where it’s described as ‘Student work from a projective geometry block in a Waldorf high school’. The image was added to both the projective geometry article and the Waldorf article by the same user (not the original uploader of the image), who doesn't seem to have any background in meteorology. This makes me suspect that the ‘polar’ may have been added in error.

On the ‘Projective geometry’ page, the image is described as being ‘based on the work of Lawrence Edwards’. Almost certainly, this must refer to Edwards’ book Projective Geometry, which seems from the reviews to be rather esoteric:

‘The reason why modern materialists are unable to understand anything of a spiritual nature is that their ways of thinking, based purely upon sense perception, are much too rigid. Books such as this can help loosen such rigidity.’
‘… some of the terms that Edwards uses (e.g. "breathing involution") may actually be his own creation… and this made cross-referencing the book with other projective geometry texts a little harder.’

The same author has written a book entitled The Vortex of Life – again, not related to meteorology – suggesting to me that he may be quite keen on the word ‘vortex’, perhaps in a broader or more unusual sense than one might find in the mainstream of scientific literature.

In short: the word ‘polar’ may or may not have been added in error by a Wikipedia editor, but in either case I am fairly confident that the ‘polar vortices’ referred to here have nothing to do with meteorology.


Is everything affecting everything on Earth? If a single butterfly can alter the future, then can't every single action keep the future in chaos? According to the question about butterfly effects, this must be so, is it not?  If this is an accurate description of the physical world, if so many things act continuously on other things, is there a way to predict anything or action at all?  If so, why are we worrying about it?

Do you know what the weather will be in four hours time? You can probably make a very confident guess. How about this time tomorrow? You can probably make a reasonably confident guess. How about this time, in fourteen days exactly? Now, you're much less confident.

That's because weather is a chaotic system, and it's very sensitive to boundary conditions.  In such a system, very small disturbances can make very big changes, far enough out.

Now, for Wisconsin (as that's what the OP's profile gives as their location), let's think about the external air temperature at 05.00 on 1 February 2017, and at 14.00 on 1 July 2017. Which do you think will be higher? Will it be a difference of a few Kelvin, or more than ten Kelvin (18°F) difference? How confident are you in your answer? You're probably very very confident that the July temperature will be higher, by more than ten Kelvin. The climate is still reasonably predictable months or years ahead, even though it gets very hard to predict the weather reliably more than ten days ahead. Climate is a long-term system, and is not sensitive to boundary conditions in the same way that weather is.

If you roll a fair six-sided dice once, you can't be very confident about whether a one will come up, however much you know about the air movements in the room when you throw the dice (you can be reasonably sure that the probability is 1/6, however much you know about the air). However, if you roll that dice 6000 times, you can be reasonably confident that one will come up a thousand times, give or take a hundred times, and you don't need to know anything about the air movements in the room.

That's the difference between weather and climate; even though weather is just a manifestation of climate, it's just a sample from the climate distribution.

We've built the global economy, patterns of habitation and movement, food supplies, energy systems, around the climate that we've had for the last few hundred years. And that should be ok, because climate, sea levels and sea pH levels normally take between thousands and millions of years to change radically. But our releases of greenhouse gases are now causing big changes to happen within years to decades: and it will be enormously expensive, disruptive, and cause huge suffering to billions of people, to reorient the global economy, patterns of habitation and movement, food supplies, and energy systems, to newer, unknown, unfamiliar climates, coupled with rising sea levels and ocean acidification.


Who are the 3% in the often cited "97% of climate scientists"? The media have variously reported that:

  Ninety-seven percent of climate scientists agree that climate-warming
  trends over the past century are very likely due to human activities.

Based on this study. My question is, who are the 3%, who do not agree on anthropogenic global warming, and what are their main lines of reasoning? It seems that the fact that these scientists represent a small minority is simply an "Argumentum ad populum", not a real refutation, and I'd like to learn more.

As the abstract makes clear, the finding of Cook et al. (2013) is not really "97% of researchers agree..."; rather, it is "97% of peer-reviewed publications agree". They didn't just go through some directory of climate researchers asking them what they thought. They read the abstracts of all 11,944 publications they found on the topic, and classified them according to what the abstract said. (The classification was blinded and crowdsourced -- read the paper for details.) As a secondary check, they asked the original researchers themselves to evaluate their own abstracts, presumably to control for any bias which Cook et al. might be bringing to the evaluation. The proportions of abstracts endorsing the consensus were 97.1% and 97.2% respectively for the two methodologies.

Note that this isn't asking researchers anything about their own beliefs. Imagine that, for instance, Jane Q. Scientist privately believes that the earth will cool by 5°C in the next century, but that she hasn't found any solid data to back up this belief, so hasn't yet managed to publish anything supporting it. However, in 1998 she published a paper which provided evidence for anthropogenic global warming. Perhaps she now disbelieves the conclusions of that paper, but it remains in the literature because the data and reasoning were strong enough to stand up to peer review, no matter what the original author now thinks. In practice, of course, it's likely that scientists' personal beliefs will be similar to their published results, but I feel it's very important to stress that this study is not an opinion poll -- it's an evaluation of the research itself. (The media can be a little sloppy in their reporting of this distinction.)

Thus, your question is a little misconstrued: we can't answer "Who are the 3%?" because the 3% are research articles rather than people. However, we can ask "Which are the 3% of published research abstracts which do not support the scientific consensus?" And since Cook et al. (2013) is an open access paper with supporting data provided, you can easily answer this question for yourself: simply download the data file from the supplementary data page and look at the papers with an endorsement rating of 5, 6, or 7. (It's in CSV format, so is easy to load into a spreadsheet or text editor.) Further supplementary data is available from the project page at Skeptical Science, and replication of the research is actively encouraged. If you're interested in the actual people behind the 3% of "non-consensus" papers you can look at the author lists for those publications (though of course there's no guarantee that all those authors would still stand by all their conclusions).

I suggest that you start your investigations by reading the paper itself. It's clear and concise, and will give you much more thorough information about the methodology and supporting data than I've been able to fit into this answer.

Cook, J., Nuccitelli, D., Green, S. A., Richardson, M., Winkler, B., Painting, R., ... & Skuce, A. (2013). Quantifying the consensus on anthropogenic global warming in the scientific literature. Environmental Research Letters, 8(2), 024024.


What happens when the North and South poles flip? How long does it take the magnetic field to move once the poles start to flip?
What environmentally would change? Does the core of the Earth flip?

The magnetic poles are moving now. When will it start to move faster and how would a compass behave?

https://www.space.com/43173-earth-magnetic-field-flips-when.html

First of all I will try to explain what a geomagnetic pole reversal is.

A magnetic pole reversal happens when the magnetic field weakens until it can no longer sustain itself. This can take 1000-3000 Years or more to complete the time it takes is very variable.

After years with a weak and sometimes variable magnetic field. The magnetic field re emerges in its original, or in a changed direction. So it is not the poles moving over the surface of earth.

Link https://en.wikipedia.org/wiki/Geomagnetic_reversal

What happens during a geomagnetic pole reversal.

During a pole reversal earths magnetic field is weak so our planet is less protected from cosmic radiation and from the solar wind.

Link https://en.wikipedia.org/wiki/Earth%27s_magnetic_field

This increase in cosmic radiation does not fit any of the known extinction events that have happened in Earth's history. This does not mean nothing at all will happen to life during this time it only means the dangers are low.

If you want to follow how the cosmic radiation changes you can do this on the last part of this page http://spaceweather.com/

Link https://en.wikipedia.org/wiki/Cosmic_ray

I mentioned in my comment Earth's magnetic north pole is really in the south. To understand how this can be true in a magnetic compass the magnetic north pole is repelled by Earth's north pole so it does point in the opposite direction (a bad explanation but it is how it works).


Are there any general-purpose climate-model coupling projects? In climate modelling, there are three major model types that form the basis of a fully coupled Atmosphere-Ocean General Circulation Model (AOGCM):

Atmosphere circulation models
Ocean circulation models
Land surface models

There are at least 10-15 well-known models of each type that are widely used. Each atmosphere model usually has one, maybe two ocean models, and one or two land surface models that it has been made to work together with as an AOGCM. But if you want to use one atmosphere model with arbitrary ocean and land models, you usually have to modify the models to some degree to get them to play well together.

Are there any projects that aim to be a generic "glue" between any combination of climate models? This could be in the form of a software framework, or it could just be a specification for data format and exchange methods.

Coupler software (e.g. OASIS, MCT, C-Coupler) is frequently used to combine these different components of earth system models. Of course interfacing models with each other using these couplers or other methods always needs some technical work and sometimes also some algorithmic work. Therefore the number of model combinations will always be limited.


If I can drill a hole to mantle, does it form a volcano? Suppose if I can drill a hole to mantle at arbitrary point of crust, will magma start rise from the hole and finally become a volcano?

As Bon says, the mantle is solid, albeit somewhat viscous / plastic under the prevailing pressure and temperature conditions, so your hypothetical borehole isn't going to puncture any liquid magma chamber. Could it liquify if suddenly depressurized in a borehole? I doubt it, although it might do so if there was a local concentration of volatiles to depress the melting temperature.

But the question is forever going to be hypothetical because there is no drill string capable of cutting into the lower crust, let alone the upper mantle. The heat would soften the drilling bit to the point where it was like putty. Also, the lateral rock pressure would be so high that the borehole walls would implode.


Database of mineral with images for a neural network application I'm diving into data science and I'm looking for a complete database of minerals.  I downloaded the csv file from http://rruff.info/ima/ . It contains 5516 lines of data but it does not have images or urls. Does anyone know if there is a database of minerals with images? I'd like to find it to train a neural network.

First of all rruff.info is an excelent site done by chemists to take data quickly, and you can totally trust the source.

Second, for images, most of the listed +5000 species are not shown in nature, and you cannot have pictures of all of them. You will only find on the net pictures from common minerals on nature.

Third it depends if your work is gonna be published or not, as you would need permission or CC licensed images if so.

Copyrigthed database of pictures and data:

Webmineral
Mindat.org

Mindat can share with you their data, and they are going soon to open them on CC format with an API, but the pictures they have belong to each author and many of them are copyrigthed (and gonna stay copyrigthed if they open data, you would need to ask permission individually for each picture).

CC license pictures:

I wondered how to obtain pictures from common minerals on CC license because I am writing a mineral app and my choise was Dr Lavinsky collection uploaded to wikipedia from his mineral shop iRocks.com.

At his website they have plentifull of high quality well described pictures of common minerals you can maybe download with a script making GET petitions, and you can ask them for permission, even for the pictures that are not uploaded to the wiki. I did it myself for my mineral guide and they just ask me to quote iRocks.com; they are very fair people. Aparently they are happy to share if you quote his shop.

At Wikipedia you can find on CC license >2000 pictures uploaded from mindat.org, and >5000 uploaded from iRocks.com

You have the complete list of minerals with picture on Wikimedia Commons where to start to collect the data. I don't know if you could somehow extract all the images url using GET petitions with code. Myself I only took the iRocks pictures because my guide covered only 180 minerals, the descriptions Dr Lavinsky provides are valuable (example), and then I only needed to quote one author (I ended by taking them directly from iRocks and link on my work to each piece on his shop, they got very happy about that, they answered my mail with "many thanks").


Did the formation of Panama trigger the beginning of Ice Ages? I have been studying ocean currents and associated energy flows in the eastern Pacific and western Atlantic oceans.  I also looked at El Nino cycles.

I also noted when the large glacial periods started 3 million years ago and noticed that these began when what is now Panama formed between North and South America by continental drift effectively separating the Gulf of Mexico from the Pacific Ocean.  The ocean currents from the Atlantic and Pacific no longer mixed from then on.  However, this article in Scientific American mentions some evidence that the isthmus of Panama actually formed enough to block ocean currents 10 million years ago.

I am not sure on the macroscopic thermodynamics on how this contributed to the start of the Ice Ages but this is the situation.  Could be coincidental.

The closing of the Isthmus of Panama alone did not trigger the beginning of the Ice Age, but it is a potentially decisive step on the way of ice shield build up in the north.
The development that leads to the current Ice Age, per definition a phase in earth's history were polar and continental ice shield build up, starts much earlier. Cooling began after a greenhouse phase already 60 million years ago at the end of the Cretaceous, possibly because of declining atmospheric CO2 levels. Intense volcanism (flood basalts) and the Chicxulub impact surely have contributed to peak cooling at that time.
During the late Paleogene and Neogene, Around ~40 - 30 Million years ago Antarctica and Australia separated and the Drake Passage opened, enabling an Antarctic circumpolar current (ACC) that isolated Antarctica from global circulation. Though the role of the current is debated, it coincides at least partly with ice shield buildup in Antarctica, but declining CO2 may have played an equal or even bigger role. The uplift of the Tibetian plateau may have contributed to cooling by chaning continental circulation patterns. Reason for the CO2 carbon decline in the late Paleogene/early Neogene may be increased silicate weathering in the course of the Himalayas and the Alpine orogeny.
So, when the Isthmus of Panama closed (exact date debated), it was already pretty cold compared to the Cretaceous and an ice shield covered Antarctica. The closing is hypothesized to have steered the gulf stream farther north, enabling the transport of moisture and warm air to the north and thus ice shield build up there.
We also should keep in mind generally ice shield buildup has a feedback in itself by rising the albedo, thus reflecting more energy back to space.
It is a complicated path to the current Ice Age with a lot of facets, starting in the late Cretaceous.


Ore Deposit Identification What type of ore deposit does this rock best represent?

A rock with a porphyritic texture is cross cut by a stockwork of
quartz veins.  Bordering the veins is extensive alteration of the host
rock. The vein contains fine-grained (~1mm) chalcopyrite and
molybdenite.

I believe it to be a hydrothermal ore deposit as porphyry ore formation, stockwork and the Cu-Mo-Au element list indicates.
Is this a correct line of thinking and if so is it specific enough, do you think?

This is the classic description of a porphyry copper-molybdenum deposit.
What happens is that there is a magmatic intrusion (the porphyry), which then solidifies. When it solidifies, it expels acidic hydrothermal fluids which carry metals in them - most often copper (represented by chalcopyrite) but also sometimes molybdenum (represented by molybdenite).
Once the fluids hit solid rocks, they react with it, and become neutralised. The carrying capacity of the fluids diminish, and they deposit the metals into the minerals you observe. The solid rocks can be pretty much anything. It can be the porphyry itself, another porphyry that happened to be around, sedimentary rocks, or whatever.


Where can we see the noctilucent clouds? I saw many pictures of noctilucent clouds in the UK. Is it a phenomenon only visible in the UK or we can see it somewhere else?

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.


What would a graph of magnitude >7.5 earthquakes over last 400 years compared to Grand Solar Minimums look like? I am a novice here and I really appreciate the graph of magnitude >7 earthquakes related to 11(22)yr solar minimum cycles.

I was wondering what the correlation would be (if any) if we changed the window to  consider 7.5 and above quakes over the past 400 years  (assuming such data is available and reliable)?

Also, some discussion about the difference between Solar Minimums and Grand Solar Minimums would be helpful.  In other words are there set periods in which Solar Minimums are even smaller than usual (Grand Solar Minimums) and do really large earthquakes tend to happen during these periods?

Thank you for your interest.

As others have pointed already in the comments, there is no earthquake data extending that far back. But we do have data for the last century. In a similar way to my answer to this question. Here I've plotted the yearly count of all of the earthquakes worldwide from 1900 to 2018 of magnitude greater of 7,7.5, 8, or 8.5 found in the USGS Earthquake Catalog that span back to year 1900 (bars), along with the total number of sunspots per year from the Sunspot Index and Long-term Solar Observations (red line).  Here is the resultant graph:

As you can see, there is not any significant correlation between frequencies of large earthquakes of any size and the solar activity. The solar record shows the well-proven 11 year solar cycle (actually it's a 22 year cycle with two similar halves). On the other hand, the earthquakes show no clear pattern.

Unfortunately, for the grand minimums like Maunder and Dalton's solar minimums we do not have a reliable earthquake record. Nevertheless, given that EVERYTHING we know about physics and earthquakes suggest that there is NO mechanism by which solar activity could possibly influence earthquakes. And provided that there is no evidence of such correlation in the 100+ years of the instrumental record. There is absolutely no reason to believe that such correlation exist. The answer to this question should be informative too.


What are these radial line patterns shown in representations of antarctica? In the video of the recent Iridium-6/GRACE-FO launch at about T+ 33:00 (curently at 49:00 in the video) the 2nd stage passes over Antarctica and this is shown in the animation.

I noticed a strange pattern of radial lines drawn on Antarctica, presumably near the South Pole. I remembered seeing these before and assumed them to be some kind of graphics glitch, until I saw something similar in the BBC News article Giant canyons discovered in Antarctica.

Are the patterns in the two images related, and what do they mean?

I can't be sure, but I strongly suspect that the radial lines in the first two images are the result of a bug in the software used to draw the map, probably resulting from vector polygons that are described in an inappropriate coordinate system going around, or too close to, the south pole.

It's impossible to guess at the meaning of the blue lines in the third image without any caption or context, but from referring back to your link for the article that you took it from, my guess would be that the lines show the tracks of the flights that gathered the data.

No, they are not related to each other.


How to convert mol/m^2 to total mass ( e.g gram, kg etc )? I want to calculate the total $\rm{NO_2}$ amount in a year using satellite Sentinel-5p NO2 dataset. But the problem is sentinel satellite data stored in $\rm\frac{mol}{m^2}$ unit. But I have to compare it to lb or ton or any other unit to compare $\rm{NO_2}$ amount with ground-level $\rm{NO_2}$ measurement.

  Example: In our satellite dataset, we have tropospheric $\rm{NO_2}$ column number density which unit is $\rm\frac{mol}{m^2}$. We want to calculate
  the total yearly $\rm{NO_2}$ of California. So we have summed all the year
  data of California. Then we get a total yearly $\rm{NO_2}$ 4200 $\rm\frac{mol}{m^2}$. I
  want to convert this to gram or ton or lb. For example, the
  total yearly $\rm{NO_2}$ of California is 35000 ton.

Also, if I convert that $\rm\frac{mol}{m^2}$ to $\rm\frac{molec}{cm^2}$, is it then possible to convert it to total gram or ton?

Research: I have asked that question in here. After getting answers, I thought I have found the solutions. But after some more research, it turns out not easy. Because in satellite data what we get is tropospheric vertical column number density and convert them to total mass like total $\rm{NO_2}$ in gram or ton is not straightforward. These forum posts (#1, #2, #3) also somewhat similar to mine, but I didn't get quite a solution to my problem.

EDIT: I know that we can easily multiply by area in $\rm m^2$ to cancel out $\rm m^2$ in the unit and multiple by $\rm{NO_2}$ molar mass, but this is not a ground-based problem. We are talking about satellite imagery dataset especially tropospheric vertical column density. #1, #2, #3 These posts shows why it is different for converting satellite imagery units to ground-based units.

$\rm \frac{mol}{m^2}$ shows the amount of $\rm{NO_2}$ in the atmosphere over a square meter of surface area - in mols.

The molar mass of the $\rm{NO_2}$ is $14+2\cdot 16=46$. It means, the mass of 1 mol of $\rm{NO_2}$ is $\rm{46g}$.

The surface area of the Earth is 510million $\rm{km^2}$. Thus, 1 $\rm \frac{mol}{m^2} \rm{NO_2}$ translates to $\rm{46 \frac{g}{m^2} \cdot 5.1 \cdot 10^8 km^2}$, what means a total mass of $23.46\cdot 10^9 \rm t$ in the whole atmosphere.

Here we assumed a constant distribution of the $\rm {NO_2}$ in the atmosphere, which is typically not the case in earth science-related problems. Also your research question is about the visualization of a highly non-level distribution. Here you need to integrate (or, considering your digital evironment, sum).


Why One Side of Mountain Range is Lush I'm new to this site and certainly not someone with any real background in atmospheric science, so please forgive me if this question is a little stupid.

I recall learning in High School about mountain ranges frequently being dry on one side and lush on the other. The explanation was that as a cloud approaches the mountain from the lush side, it releases any rain so it can rise over the range. This always seemed like a silly explanation to me, because in the way it's phrased, it seems to imply that the cloud is cognizant. Also, this would mean that clouds can only (for the most part) approach the mountain from the lush side, which may or may not be true, but I don't know why. So I'm sure there's a better explanation as to why this happens, but I'm hoping someone can explain.

Thanks

The Cascade Mountain Range in the US Pacific Northwest is a good example to use to explain this. The predominant wind direction is from the West - over the Pacific Ocean. The air over the ocean picks up moisture from evaporation. After it passes the coast, the mountains cause the air to rise. As it does so it cools. Colder air can hold less water vapour than warm air so that the air becomes saturated with water and it condenses out into clouds. With enough condensation you get rain - a lot of it on the western side of the mountains. So you had it backwards, the rain doesn't allow the air to rise - the rising allows it to rain. Clouds mainly approach from the lush side because that is the prevailing wind direction but it is better say that it is the lush side because clouds mainly approach that way. When wind comes from the other direction is travelling across land so it contains less water and the cooling generally isn't enough to cause rain.

Once the air crosses to the other side of the mountain range it warms and becomes undersaturated with water. Clouds often disappear and even if they remain you aren't getting further condensation to produce a lot of rain. So those areas are much drier.


How does argon-argon dating work - need a simple but not-wrong explanation The Washington Post article Scientists discover hundreds of footprints left at the dawn of modern humanity describes the geological dating of  stratified layers of mud by analyzing and dating minerals within each layer.

But since floods jumble materials of different origins and ages together, that meant the scientists had to date dozens of different minerals. The youngest crystal in the footprint layer would represent the oldest possible age for the prints; the oldest crystal in the layer above it would represent the youngest they could be.
Using the argon-argon dating technique, by which scientists measure the decay of an isotope called Argon-40 into Argon-39 in order to find the age of crystals, they came up with a rough approximation of the footprints' age: 19,000 years at the oldest, 10,000 or 12,000 years at the youngest.

I can't exactly follow the logic, but I'm asking here about the dating process itself. How does argon-argon dating work?
I do not think that Argon-40 decays into Argon-39 as the article states, at least not all by itself. And when I look at the Wikipedia article, the discussion is so technical and defensive that I can't actually picture what is going on.
How does argon-argon dating work?

As noted in the comments the wikipedia articles (at the time this question was submitted) are contradictory. There are quite a few steps to the logic of how argon-argon dating works but none are too complicated, although I won't go into all of the possible interferences. One thing to keep in mind is that high-precision isotope measurements always measure ratios between isotopes, not absolute concentrations.

To understand argon-argon dating, you need to understand potassium-argon dating.

The isotope potassium-39 makes up about 93% of natural potassium. Potassium-40 is radioactive but has such a long half-life that it is primordial - it has been around since the earth was being formed. Because of this, we can assume that the potassium-40:potassium-39 ratio in minerals at any time is a constant. Potassium-40 decays in 2 different ways. Most decays by beta decay to calcium-40. About 10.7% decays to Argon-40 by emitting a positron.

If the argon-40 stays trapped in the crystal and you can measure the ratio of potassium-40 to argon-40, then you know how long it has been since the mineral formed. This also assumes that there is no other source of argon like trapped air. A problem is that it takes two separate measurements to get the potassium concentration and the argon isotope ratios, increasing the uncertainty. Argon-argon dating gets around many of the issues by measuring only multiple isotopes of argon.

The trick is to irradiate the sample with neutrons along with samples of known age. Some of the potassium-39 forms argon-39 by an n,p reaction. By converting potassium-39 to argon-39 then measuring the argon-39:argon-40 ratio, you can calculate the sample's potassium-40:argon-40 ratio, remembering potassium-40:potassium-39 is fixed. The standards of known age are used to account for differences in the neutron flux during irradiation. Argon-36 in the sample accounts for any air contamination.

Argon-argon dating, ideally assumes that:

all argon-40 in the sample comes from either atmospheric argon or from decay of potassium-40 in the sample
all argon-39 in the sample comes from irradiation of potassium-39 in the sample and as noted above, if you know potassium-39:argon-40 ratio then you know the potassium-40:argon-40 ratio because the potassium-40:potassium-39 is constant (at this point in time)
all argon-36 is the sample is from atmospheric argon

The actual calculations are pretty simple algebra, combining all the pieces.


What is the long term impact of large scale removal of material from subterraneal caches on the structural integrity of the soil? For example, sinkholes can be human induced:

  New sinkholes have been correlated to land-use practices, especially
  from groundwater pumping and from construction and development
  practices. Sinkholes can also form when natural water-drainage
  patterns are changed and new water-diversion systems are developed.
  Some sinkholes form when the land surface is changed, such as when
  industrial and runoff-storage ponds are created. The substantial
  weight of the new material can trigger an underground collapse of
  supporting material, thus causing a sinkhole.

We have been pumping oil out of the ground, fracking, extracting natural gas, mining, etc. for a long time now and in some instances to the point that we completely deplete such reserves. What is the long term impact of anthropogenic removal of material from the underground on the ability of the foundational soil to support our ever expanding population and associated infrastructure?

The answer to your question will depend on the type of material and the depth. I will restrict this answer to groundwater withdrawal to focus the discussion.  Of course there can be effects from other extractive industries.

Groundwater pumping can lead to large scale subsidence, with the Central Valley of California being one of the best described examples. According to that website, "More than 80 percent of the identified subsidence in the United States is a consequence of human impact on subsurface water."

Overall, the extreme subsidence shown may cause damage to foundations, etc. but is spread over a large area and is pretty even, unlike your classic sink-hole.  It is the differential settling that causes the most damage.

There are several types of sink holes (also called dolines), they may be related to failure of indurated rock above cavities or by failure of soft soils/sediments. The most common natural sinks occur through the dissolution of limestone in 'karst' terrain and they can be kilometers across. This can lead to the creation of water or air filled caves. In some cases a cavity forms in sediments above the limestone and can subsequently collapse. Cavities can also be formed in sediments where they are removed through pipe erosion but that tends to be a shallow phenomenon (but can still be damaging).

The description, above, talks about natural processes but these can be enhanced by groundwater pumping.  The water supports some of the overburden and removing it weakens the structure and can lead to collapse. Flow systems can change, enhancing subsurface soil erosion as water tables decline. And of course, building over a cavity may exceed the load bearing capacity.

So the long term impacts will depend on both the geologic setting and the severity of water level decline. Will this have a major effect on global infrastructure and economies? I suspect not but the damage we have seen in certain areas is likely to continue and perhaps spread.

A somewhat old but good reference on the subject sinkholes and caves that discusses the land-use issues is Geomorphology and Hydrology of Karst Terrains. White, William B. (1988). Oxford University Press.


Thermohaline current in North Atlantic The thermohaline current in the North Atlantic ocean sinks because it gets cooled, or it gets cooled because of sinking?

Complementary to the points about salinity emphasised by TomO and S Verhoef, one more point to emphasise is the role of deep ocean convection. You may have in mind this picture of water sinking because it gets heavy, which is not quite wrong, but you get a more accurate picture if you see that the water column down to about 3000 meter deep is convectively mixing (mainly in winter) in localised areas of the  Greenland, Iceland, Norwegian and Labrador seas. Convection is what you get when dense water lies above lighter fluid, which is as unstable as an egg on its head.

The consequence of this mixing is twofold.

First it shapes the hydrological structure of the deep ocean and determines its organisation into distinct water masses (e.g.: http://www.soes.soton.ac.uk/teaching/courses/oa631/plot_20w.jpg )

Second it induces a strong cooling of the ocean water masses.

Together these effects control the strength of the meridional overturning cell.

If your are after an advanced and authoritative review on this, see http://onlinelibrary.wiley.com/doi/10.1002/2015RG000493/full, which is open access.


How do we know how much Uranium was in any given sample when it was deposited? Concerning "Uranium-series dating", also known as "Uranium-thorium dating".
 Uranium is present in deposits, "typically at levels of between a few parts per billion and few parts per million by weight", according to the wikipedia article on the subject.

As an example, with carbon dating, the amount of carbon-14 originally present in any given sample is consistent with the amount of carbon-14 created by the activity of sunlight in the atmosphere.

How do we know how much uranium-234 was in any given sample of rock when it was created/deposited?

The chemistry of lead is very different from that of uranium and thorium. There are key kinds of rock that could not possibly have been formed with even the smallest amount of primordial lead. The lithophilic nature of uranium and thorium means that those same kinds of rock could easily have readily accepted primordial uranium or thorium.

Any lead in those kinds of rocks must necessarily be the result of decay of uranium or thorium after the rock formed.


Can we define "drainage density" for a soil column (point-scale)? From what I read all over the web and articles, drainage density is a parameter that is defined for a catchment.
I want to use a hydrological model to simulate the percolation from the bottom of a soil column, therefore my spatial scale is point-scale.
This model both works in point-scale mode and distributed mode. In the point-scale, I still need to choose a value for the drainage density (DD).
As described in this paper :
$$ DD = \dfrac{1}{2 HL} ,$$
where $HL$ is the length of hillslope.
Any idea how to calculate $HL$ for a soil column?
Can I say $HL$ is equal to the depth of the soil column (surface to the seepage face)?
Or it doesn't make sense to define DD in the point-scale?
In this model, DD affects the ratio of $\dfrac{lateral flow}{percolation}$. As for the lateral flow in the soil column, beside the topographical slope and soil textures, is there any other parameters that is important to consider?
Please let me know if I did not explain my question clearly.

Fundamentally it doesn't make sense to describe the point scale model with hillslope length and drainage density. If you are looking to model a soil column, you could use Darcy's law or Richard's equation. If you are looking to model the catchment, the point scale is not appropriate, although you could always incorporate those point-scale appropriate equations into a more complete hydrologic model if you wish (something like HydroGeoSphere does), but that is still a catchment scale model.
In either case, this comes back to 1) what is the purpose of your modelling exercise, and 2) making sure that your choice of model is appropriate for that purpose. A hydrologic model that uses hillslope length for a point scale is not an appropriate choice for what (I think) you are trying to do.


How much is Iceland/Norway/Western Europe warmed up by the Meriodional Overturning Circulation? A shutdown in the circulation was associated with the Younger Dryas stadial, also referred to as the Big Freeze, so I'm curious how much warmer Western Europe is due to the MOC, and how much heat (in Joules) the MOC actually releases into the region.

To answer the numerical aspect of your question: Rintoul & Wunsch 1991 advanced a poleward heat flux in the North Atlantic (i.e. that generated by the Gulf Stream) of $1.3\pm0.2\times 10^{15}W$.

That number of 1.3 PW (PetaWatts) have been reused in several reviews on the thermohaline circulation such as Clark et al. 2002; hinting that this number is at least realistic (since I'm not a physical oceanographer myself it is difficult for me to judge otherwise).

References:
Clark, P. U., Pisias, N. G., Stoecker, T. F., Weaver, A. J. 2002. The role of the thermohaline circulation in abrupt climate change. Nature, 415: 863-869.
Rintoul, S. R., Wunsch, C. 1991.Mass, heat, oxygen and nutrient fluxes and budgets in the North Atlantic Ocean. Deep Sea Research Part A, 38: S355–S377.


Does lapse rate apply below sea level? In many parts of the world there are dry lands below sea level, such as parts of the Netherlands. Since we know that temperature decreases with increasing altitude, does it mean that temperature will increase as we go lower below sea level?

Yes.  The height of the ground or ocean surface is of no consequence to the lapse rate as long as we remain above it -- in the atmosphere.  E.g. the dry adiabatic lapse rate is a conservation of entropy as a parcel of air rises or descends.  This means the temperature change is related only to the expansion of contraction of the parcel as it responds to changes in pressure.  When you move down below sea level there is nothing fundementally different than starting at 500 m height and moving down from there.  Both are moving down into higher pressure and the parcel will contract and warm as a result.


Where does the lithium in Salar de Uyuni comes from? Salar de Uyuni in Bolivia holds a large percentage of the world's lithium reserves. Since the lithium is dissolved as LiCl in the brine, it makes extraction much easier than the alternative: Li bearing minerals in granitic pegmatites.

What is the source of lithium in the brine? Where does it come from?

Due to its increasing economic importance, Lithium deposits are coming under more intense scrutiny, by organisations such as the United States Geological Survey (1).  The Salar de Uyuni deposit in Bolivia is one of the deposits of lithium brine that is undergoing modelling and research.

The USGS noted that all lithium brine deposits have some very similar characteristics, climatically, they are in arid environments, be near one or more aquifers and have had sufficient time for the accumulation of the lithium from weathering processes, other commonalities include the tectonic settings, associated volcanic/hydrothermal activity and local petrology (lithium bearing rocks) (1).

The geological setting of the Salar de Uyuni is described by the USGS (1) as being situated in the Altiplano of Bolivia and Chile - a high, internally drained plateau along the crest of the Andean convergent boundary orogen, that includes closed basins. Active faulting is present, causing in subsidence, allowing sediments to accumulate.

Observations made by Hofstra et al. (2013) (2) in similar lithium brine deposits in the United States came to the conclusion that melt inclusions in quartz phenocrysts in rhyolite tuffs in association with hydrothermal deposits of tin, molybdenum and beryllium have been found to be heavily enriched in lithium (to the order of 1000's ppm).  Hofstra et al. (2013) surmise from these observations that the source of the lithium has been leached out over time from the nearby rhyolitic tuffs of the Bolivian tin belts to the east of the Salar de Uyuni (2),(3).

The lithium is then leached out of the rhyolite by meteoric water, draining into the basins and concentrated by evaporation in the local arid environments.

References

(1) Bradley et al. 2013, A Preliminary Deposit Model for Lithium Brines, USGS Open-File Report 2013–1006

(2) Hofstra et al. 2013, Silicate Melt Inclusion Evidence for Extreme Pre-eruptive Enrichment and Post-eruptive Depletion of Lithium in Silicic Volcanic Rocks of the Western United States: Implications for the Origin of Lithium-Rich Brines*, Economic Geology

(3) Arce-Burgoa and Goldfarb, 2009, Metallogeny of Bolivia, Metalliferous Ore Deposits of Bolivia


How high do you need to be to see Los Angeles from Washington DC? If you were to stand on a tall building in Washington, DC and looked west, how tall would the building need to be to see Los Angeles? I would like answers based on if the world was flat and if the world was round. The distance is 2300 miles from Washington, DC to Los Angeles, California. According to Visual Line of Sight Calculations, the Earth's curvature has an average curvature of 7.98 inches per mile.

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.


Does the configuration of a confined layer change the storage? I have a confined aquifer of sand. I will temporarily drain the aquifer, remove the top one meter of the aquifer and then replace that with a layer of gravel. After that I will restore the layer (and the aquitard above it). After that, it is a confined layer again.

Is the storage of the aquifer different with the small layer of gravel?

Under normal conditions a layer of gravel has more hydraulic conductivity in comparison to sand. Check this table with a hydraulic conductivity k per soiltype

The storage in the aquifer with gravel will be larger than in sand if the same thickness is used. Otherwise you should take the thickness into account as well (= Transmissivity: kD).


How would a world entirely covered in oceans get the nutrients to support life? On earth nutrients flow from the land to the ocean. Life on oceans need those nutrients to trive.

I was trying to think how an ocean world might support life if there was no land to provide the necessary bootstapping nutrients.

Any thoughts?

If the planet is geologically/volcanically active hydrothermal vents are a way by which nutrients, in the way of minerals and chemicals, can enter the ocean.

Certain types of bacteria can consume the minerals and such bacteria form the base of a food chain. Also, the heat from the hot water can provide energy to life forms.


Effect of reducing conditions on melting point I've been reading a paper(*) looking at the deep carbon cycle and it mentions a key process that the authors refer to as "redox melting". According to the paper, reducing conditions increase the melting point of the rocks at depth, which affects partial melting. Can anyone explain why the redox state has an impact on the melting point?

(*) Foley & Fischer (2017) An essential role for continental rifts and lithosphere in the deep carbon cycle, Nature Geoscience 10, 897–902

As you probably know, the melting temperature in the mantle is a function of H2O contents. The more H2O you have, the lower the melting point of the rocks (i.e. dry vs wet solidus in the sketch). A less known phenomenon is the decrease of melting point with the addition of CO2.

The CO2 melting curve has a weird shape. At low pressures nothing much happens, but there's a certain pressure where all of the sudden CO2 is soluble in the melt and it greatly depresses the melting point. This kink is known as the "carbonate ledge". The exact depth of the ledge depends on the composition of the rocks and the experimentalist that performed the experiments, but it's somewhere around two to three GPa, corresponding to about 65 to 100 km deep. Low degree melts above the solidus (the yellow area) are proper carbonatites, and higher degree melts are all kinds of carbonated alkaline melts, with more CO2 dissolved in them at higher pressures. True hybrid carbonate and silicate melts are only possible at pressures of let's say 4-5 GPa and higher. Below that an immiscibiliy gap exists (also dependent on the alkali contents of the melts - more alkalis = more miscibility).

redox melting

Now, for this to happen you obviously need to have CO2 in the mantle. But CO2 is the oxidised form of carbon. In general, the deeper you go in the mantle the more reduced the conditions are. The roots of cratonic lithospheric mantle are very reduced and any carbon in there occurs in the form of reduced carbon: diamonds. Diamonds are no good in facilitating carbonated melting of mantle rocks. However, if a process of metasomatism of fluid flow causes oxidation of the diamonds, they transform to CO2 thus enabling the formation of carbonated mantle melts.


What efforts have been made to separate the microseismic events related to wind-related ocean waves from the components of volcanic origin? I have read the question What generates the microseism? and it's accompanying answer.

In [#1, cited below], they use the azimuth values of seismographic activity on the flanks of the volcano Stromboli to discern where this microseismic "noise" is coming from:

  The behaviour of polarisation at the east flank lets us suppose
  that the microseismic noise comes from this direction.
  This is the direction of the Scirocco wind (south, southeast
  direction) that blows on Stromboli during summer season.

So, according the other answer on the site, these low frequency oscillations are due to the wind's effect on the waves of the ocean.  In the initial question that sparked the answer, it was cited the frequency of these ocean waves was 0.2 Hz, which is in the 0.1-0.5 Hz region that the Stromboli researchers were looking at.

The whole crux of the Stromboli paper was that the microseismic events (volcanic and non-volcanic) were enough to confound the separation of the tremor signals into independent components  These researchers were using independent component analysis (ICA) and were able to pull a 0.2 Hz and a 0.4 Hz component out of the mixture (likely corresponding to the 0.2 Hz ocean wave energy mentioned in the other question).

The remaining energy in the microseismic range (which can be seen in the first two components) is preventing further separation of the other components of the microseismic activity .

Stromboli has a constant tremor due to its ongoing activity, but have there been efforts elsewhere to suss out which of the microseismic activities are from sources in the ocean versus those coming from intermittent volcanic tremors?  Could this be achieved by using a combination of sensors, some in the ocean and some on land, or is this type of analysis not really useful?

  Reference:

  De Lauro, E,De Martino, S, Falanga, M, and Palo, M. (2006). Statistical analysis of Stromboli VLP tremor in the band [0.1-0.5]Hz: some consequences for vibrating structures. Nonlin. Processes Geophys., 13, 393–400. [DOI] [PDF] (freely available)

There have been several studies regarding the separation of volcanic and water-wave (surf) microseismic traces, recently a study was performed exactly as you asked - using and comparing data from several sensors.

A recent study at Pagan Volcano in the Northern Mariana Islands (1) demonstrated multiparameter seismo-acoustic observations of long-period signals from seismic, infrasound and buoy data can not only determine the azimuth to the source of the mcroseism disturbance, but can provide a means to compare the frequency typical of surf and those that are 'normal' for the volcano.

One of the major differences they found was when a typhoon passed 770km away from the sensors, these clearly showed the difference in the signal that ocean waves have on local surf induced microseisms - causing a peak that is not present on the volcanic microseism (as the volcano itself is not directly affected by the surf). In fact, the storm track could be tracked, something that was also done during Superstorm Sandy (2) - which presents another signal that is very different to volcanic microseisms.

The research and observations suggest that a feasible way of determining the origin of the sources to microseisms is to have an array of types and spacing of sensors.

References

(1) Lyons et al. 2014, Distinguishing high surf from volcanic long-period earthquakes, Geophysical Research Letters

(2) Sufri et al. 2014, Microseisms from Superstorm Sandy, Earth and Planetary Science Letters


baroclinic current - dimensional analysis I am puzzled by the dimensions of the formulas given here for the baroclinic component of ocean currents (first terms on the right-hand side of formulas 5 and 6).

If I am not wrong:

[f]=1/s

[$\rho$]=kg/m3

[$\frac{\partial}{\partial y}$]=1/m

[dz]=m

therefore:
$$[\frac{1}{f\rho}\frac{\partial}{\partial y}\int_{-z}^0\rho(z)dz]=s\frac{m^3}{kg}\frac{1}{m}\frac{kg}{m^3}m = s$$

What am I missing?

They are missing $g$ in equations 4,5 and 6. When they go from the hydrostatic equation to equation 4, they forget to include gravity in their equations.
All the dimensions except from $g$ and $f$ compensate each other and then $g/f$ produces the right velocity dimensions $m/s$.


Climate on Venus after it becomes tidally locked Suppose, Venus becomes tidally locked. Will its dark side cool enough so that the CO2 from atmosphere to precipitate in liquid form to make an ocean?

While Venus is not tidally locked to the sun, it rotates slow enough that you might as well consider it tidally locked.
However you have to disentangle the slow rotation from the superrotating atmospheric motion. The fast atmospheric rotation (as reaction of the atmospheric gases to the intense solar radiation) redistributes heat very efficiently in the upper atmosphere.
In the lower atmosphere, no significant winds are observed, but the atmosphere has a large density, which through heat conduction again makes redistribution of heat efficient.
All in all, Venus' atmosphere has therefore a horizontally uniform temperature. Said differently, next to no dayside-nightside temperature gradients exist. Nothing will precipitate.
Furthermore the $CO_2$ at the surface is superfluid due to the intense pressure, and this state doesn't seem to form droplets, it IS a sort of highly-viscous $CO_2 $-ocean.


What are the fields in Petrel's IESX seismic horizon file? I have a text file containing 23 seismic horizons from Petrel, Schlumberger's seismic earth interpretation and modelling tool, using the 2D IESX format. Here are the first few rows:

PROFILE Fault to seafloor    TYPE 1  5 By Petrel 2014.2 (64-bit)                2d_ci7m_gf.ifdf  m  ms
SNAPPING PARAMETERS 5     2 2
  4.19846879E+05  4.66812161E+06  1 14  2742.85   5460.00  16382.00 4262               2 276-109::normTOv
  4.19840089E+05  4.66813210E+06  1 14  2756.25   5461.00  16383.00 4263               2 276-109::normTOv
  4.19833299E+05  4.66814259E+06  1 14  2769.65   5461.00  16384.00 4264               2 276-109::normTOv
  4.19826509E+05  4.66815308E+06  1 14  2783.05   5461.00  16385.00 4265               2 276-109::normTOv
  4.19819720E+05  4.66816357E+06  1 14  2733.93   5462.00  16386.00 4266               2 276-109::normTOv
  4.19812930E+05  4.66817406E+06  1 14  2809.85   5462.00  16387.00 4267               2 276-109::normTOv
...

Each horizon starts with two similar header rows. I'm not too worried about those (but it would be nice to know about them too). I'm more interested in the (400,000 or so) data rows. Here's what I surmise so far:

(float) — x location
(float) — y location
[1-9] (int) — seems to change with each interpreted segment of horizon
14 — no idea
(float) — two-way time
(float) — no idea
(float) — no idea
(int) — CDP or trace number
2 — no idea
(str) — line::dataset

I have look at the application's documentation, to no avail. Does anyone know what the fields are?

X-coordinate
Y-coordinate
Segment number
Symbol code
Two-way time (ms)
Shot-point number
CDP number
Trace number
Line type (2=2D, I=inline, X=crossline)
2D line name or 3D survey name

The format allows for a column between 8 and 9, for amplitude value — not present in this example.

This is a formatted layout to specific columns. So there is the potential for fields to butt against each other with no spaces between.

The top 2 lines define the horizon name (after PROFILE) and various picking parameters you shouldn't need.

This answer comes from Tom Cox (geoscientist at Schlumberger).


Can the Bering Sea Rule be used to predict the weather? Recently, a colleague explained that the recent cold spell in the eastern United States could have been predicted using the Bering Sea Rule. The idea is that 17-21 days after a storm appears in the Bering Sea, a storm will appear in the United States.

Is this rule reliable?
What is the explanation for it?
What is the skill of a forecast using the Bering Sea Rule?

Here is a news report that mentions it for the recent weather pattern.

There are two papers produced by the NOAA's National Weather Service investigating the claims regarding the Bering Sea Rule (BSR) and the Typhoon Rules for long range forecasts.  Some insite for your immediate questions:

Although not giving a percent reliability of the BSR, the second
study does say that the BSR has forecast skill above climatology for
long range forecasting - see Discussion, Summary and Conclusions
section of study II.
From paper I:

  The Bering Sea (BSR) and Typhoon (TR) rules are two observations used
  by weather forecasters. The former was introduced in 2011, while the
  latter has been used since at least the 1940s and are based on the
  idea of teleconnectivity within the Pacific Ocean region which was
  defined statistically by Wallace and Gutzler (1981). For example, the
  Pacific North American (PNA) pattern will be associated with
  alternating trough-ridge patterns from the Central Pacific to the East
  Coast of the US. A ridge-trough pattern from west to east over the US
  is a positive PNA configuration, while the opposite pattern is
  negative. Teleconnection is thought to be the result of downstream
  propagation of Rossby Wave activity in the North and South Pacific
  basins (e.g., Renwick and Revell, 1999; Wang et al. 2011, and
  references therein). The Bering Sea region is close to one
  teleconnective centers in the PNA pattern, which should make these
  rules useful indicators of weather downstream.

Refer to the Case Studies in study II.

Source (Study I): http://www.nws.noaa.gov/ost/climate/STIP/39CDPW/39cdpw-JRenken.pdf

Source (Study II): http://www.nws.noaa.gov/ost/climate/STIP/40CDPW/40cdpw-JRenken.pdf


What effect does river channelization have on the surrounding water table? Correct me if I'm wrong, but most rivers lie where the water table protrudes into open air. In other words, the water table level is exactly the same as the river water level. (Wikipedia has a good diagram.)

So now the question is, what happens if you channelize the river with impermeable walls and bed? E.g., the Los Angeles River, which has concrete walls.
What happens to the isolated water table now? It is no longer free to drain into the river, so where does it go? Does it drain away more into the ground? Does it stay more saturated than normal until evaporation? And doesn't this produce dangerous ground conditions and bad environmental effects?
Water needs to follow some cycle, or it will just fill up more and more till the whole region is a flooded lake or ocean. So I'm trying to understand the water cycle in this case.

The concept of rivers being the outcrop of an aquifer at the surface is a useful generalization, but tends to simplify the real world.

The water level in a river can be higher than the water table in an aquifer. We would describe the river as 'losing' water and it would recharge the aquifer. So in that case channelization would reduce aquifer recharge and potentially lower the water table. As an example irrigation canals in arid areas are often quite leaky. Projects to line the canals to reduce leakage have frequently had the unintended consequence of cutting off local recharge to aquifers used by farmers adjacent to the canal.

If the water level in the aquifer is higher than the river we describe it as a 'gaining' river. Channelization would reduce river flow and lead to higher water tables in the aquifer. The consequence of the higher water tables might be increased spring or river flow in another part of the aquifer - or in the worst case emergence of water adjacent to the channelized section waterlogging the ground. The extreme case of filling up a whole region is improbable, as once levels rise enough the water will just flow back into the channel, or further rise will be balanced by evaporation from open water.

Stretches of river may change from losing to gaining, and vice versa, seasonally, or in response to changes in geology or topography over quite short distances. Natural river beds are often not seamlessly connected to the aquifers they run over; muds and silts on the river bed can reduce permeability and effectively cause natural channelization. Equally artificial channelization is rarely 100% effective and leak proof.


Is the ocean a carbon sink when considering only the biospheric component? Most people knows that the ocean overall is a carbon sink, but a big part of the sink is due to chemical equilibrium (via dissolution) with the atmosphere (for ref: https://link.springer.com/article/10.1007/s10021-005-0036-3). Not all the (chemically) dissolved CO2 is consumed by primary producers in the ocean (simple deduction from ocean acidification).

In terrestrial ecosystems, we have a term called net ecosystem production (NEP) which is defined as gross primary production minus the total (autotrophic + heterotrophic) respiration in an ecosystem (generally a meaningful timeframe should be at least on an annual basis). I wonder is there any research done regarding the NEP of the ocean? (I am sure there are some out there but I cannot find a conclusive summary of the entire ocean or at least a big part of the ocean). I am assuming this would be harder to measure than terrestrial ecosystems considering how big the ocean is and the big confounding factor of physicochemical processes in the ocean.

Edit: I found somebody trying to answer the same question 20 years ago (Del Giorgio, P. A., & Duarte, C. M. (2002). Respiration in the open ocean. Nature, 420(6914), 379). But in it, it said the answer remained uncertain. I am assuming there would be advances since then.

Yes, the marine biosphere is a carbon sink, and a very important one. It is known that the oceans produce more oxygen and biologically consume more carbon dioxide than all the tropical rainforests. This is done by microscopic blue-green algae, cyanobacteria and phytoplankton of many kinds. Also by green algae such as seaweeds, by sea grass meadows, and by coral reefs which are built of calcium carbonate synthesised by the corals themselves. Sea grass is an interesting plant, related to land grasses but able to survive and prosper in shallow seas where there is plenty of light and suitable soil. It is very important for the marine ecosphere. As on land, there are marine deserts where there is very little biological activity, and other areas that are teeming with life.

The question arises of how much of this captured carbon remains in the sea. The answer is most of it, but it is impossible to give exact figures. Some of the marine biomass is removed by various means, fishing for example, but that does not mean that all the carbon is returned to the atmosphere. Sea birds consume a lot of fish, and much of their guano is deposited on land, and some of them die on land, but again not all the carbon is returned to the atmosphere. There are enormous deposits of guano on the coast of South America and some Pacific islands, which are mined for fertiliser. The bodies of dead marine creatures, and sometimes live ones, are often consumed by other marine creatures. A dead whale, for example, provides a feast for all sorts of marine carnivores and scavengers. Much of the marine biomass eventually sinks to the ocean floor, where it becomes part of the ooze and sediment.


Does US have more forest fires in Sep 2020 than average? I see lots U.S. wildfires on Zoom Earth, and lots news about them. Is this amount of wildfires normal? Or is this average? If over average, why?

For now it seems to be average, at least compared to the last decade. The National Interagency Fire Center has a page with a year-to-date statistics table. You can see that so far, the values for 2020 are pretty similar (even slightly below) to the 10-year average, both in terms of number of fires and burned acres.
2020        |   Fires: 41,599   |   Acres: 5,288,247
2010-2019   |   Fires: 44,177   |   Acres: 5,761,034

Now if you go further back in time, there seems to be an upward trend. I did not compute the means, but just by looking at the numbers you can guess that there were less fires in the 80's and 90's, and about the same amount as today from the 2000's.


Is the difference in 'Summer tanning' in the Southern Hemisphere related to the Ozone hole or are there other factors? Many people have observed that people 'tan faster' in the Southern Hemisphere, compared to equivalent latitudes in Europe. Some Australians even say the sun is 'less bright' on a European beach.

Now is there some natural Earth-Science explanation for this - or do we go back to a climate-change explanation for this?

My question is: Is the difference in 'Summer tanning' in the Southern Hemisphere related to the Ozone hole or are there other factors?

Tanning is the skin's response due to the dose of UV radiation that the person is exposed to  [Wikipedia].

One major factor for the differences in tanning between the two hemispheres is that the Earth's orbit is not circular - and is at aphelion (furthest distance from the sun) during the Northern Hemisphere summer and is at perihelion (closest distance from the sun) during the Southern Hemisphere summer.  See the diagram below:

Source: NASA

Hence, a greater amount of solar radiation reaches the Earth's surface during the southern hemisphere summer.

As for the ozone 'hole', as can be seen in the image below, it only really affects Antarctica and surrounding oceanic waters to any great extent:

Source: NASA

Taking Australia as an example (as you mentioned it in your question).

According to the Australian Bureau of Meteorology FAQ about ultraviolet radiation:

  Does the Antarctic Ozone Hole ever come over Australia?
  No. The ozone hole has only ever been observed to be well south of the Australian mainland and Tasmania. In fact, during springtime, when the hole is in existence, ozone levels over southern Australian cities are at their highest.

  However, after the ozone hole has broken up parcels of ozone depleted
  air mixed with mid latitude air move northwards. These parcels can
  move over the southern part of Australia and cause a reduction in
  total ozone values.

Australia's SunSmart FAQ about UV radiation sums it up nicely:

  Why does Australia have high levels of UV radiation?

  Australia experiences some of the highest levels of UV radiation in
  the world because we are close to the equator and have a lot of clear
  blue-sky days. The Earth's orbit also takes countries in the southern
  hemisphere (Australia included) closer to the sun in their summertime
  than countries in the northern hemisphere during their summer.


Is global warming a linear process? Is global warming linear in the sense that doubling the emission of Greenhouse gases will result in a doubling of global warming. Is there a threshold, i.e. is there are certain concentration of GHG where global warming is triggered and additional gases do not lead to a faster global warming?

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.


Volcanic Eruption Calculation? I was trying to find the amount of energy created during a volcanic explosion, I have been looking around, There was one formula I found where I could use the Kinetic Energy,  which is $KE=\frac{1}{2}mv^2$, but I feel that there is something more.

I am looking at Volcanic Explosivity Index for Krakatoa, which says that it is class 6, and it has a TNT equivalence to 200 megatons.

I was hoping if someone can give me the correct calculation to find the means of measuring a volcanic explosion in joules, tonnes or higher.

Or if there are other means or formula like finding the result in newtons, go ahead with that as well

https://en.wikipedia.org/wiki/Volcanic_Explosivity_Index
https://en.wikipedia.org/wiki/1883_eruption_of_Krakatoa

Here is information about the Volcanic Explosivity Index

https://geology.com/stories/13/volcanic-explosivity-index/

It says you can measure it by volume of volcanic material, height of eruption column and duration of explosion.

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).