How to count lightning in a thunderstorm? Is there an accurate way to count the amount of lightning happening in a thunderstorm? How is lightning measured? Is there a special unit for this?

There are many types of devices used for measuring lightning. The first natural radio wave receiver was also the first lightning detector invented by Alexander Stepanovich Popov. In 1896 Popov presented a paper on a wireless lightning detector he had built that detected radio noise from lightning strikes.

Popov's discovered that lightning produces radio waves. Popov discovery originates from the fact that lightning produces light and sound. If the sound of the thunder is produced by the rippling of air because of the expansion of air produced by the heat of the lightning, then Popov thought that lightning could produce other forms of energy too. This other form of energy turned out to be radio waves.

Popov's designed a very sensitive coherer (a primitive radio signal detector) connecting it to an antenna that received the radio waves from the lightning. The coher was also connected to a circuit with a battery and a relay that rang a bell and sent a pluse to a chart recorder that could mark the occurrence of the lightning.

Popov built a radio receiver that could only receive natural radio waves from lightning (then the only good source of radio waves) leading him after to build an artificial radio transmitter.

The radio waves of lightning travel much farther than the light and sound it produces so a lightning detector can measure the distance to the lightning strike. Some of today's lightning detectors use this basic concept. With four of them you can combine the time at which each device measures the radio signal from the lightning and determine the strike location. Meteorologist today call this detector a ground-based lightning sensor.

There are other devices used to measure lightning using other kinds of antennas and signal processing techniques like radar and temperature data. Lightning detection can also be from advanced devices on artificial satellites. Using direct observations such as with the Geostationary Lightning Mapper a near-infrared optical transient detector can detect changes in an optical scene, indicating the presence of lightning, frequency and location of lightning events.

Alexander Stepanovich Popov radio receiver and lightning detector.

Further information:

Alexander Stepanovich Popov: https://en.wikipedia.org/wiki/Alexander_Stepanovich_Popov

The Popov Lightning Detector: http://weatherbreak2.creighton.edu/?p=1809

A Brief History of Lightning Detection: http://scijinks.jpl.nasa.gov/lightning-detection/

Geostationary Lightning Mapper (GLM): http://www.goes-r.gov/spacesegment/glm.html


Why do trees break at the same wind speed? Several people have independently mentioned to me that all trees break at the same wind speed. This phenomenon is independent of type and size of the tree. Supposedly, Galileo already had described this phenomenon in one of his books. I think the wind speed was something like 150 km/h. I just do not understand what can cause such behavior to be valid for all size and types of trees.

Why do trees break at the same wind speed?

Image source: Wikimedia Commons
Note that in the above image, that almost all of the trees had their tops snapped off. This claim is about tree's being snapped in two and is not about trees falling over or being uprooted.
This claim is approximately valid for many species of trees. Apparently oaks can withstand slightly higher wind speeds than can pines. This claim does not apply to non-woody trees such as palms. It also is not true for species of woody trees that have evolved to live in areas where winds occasionally exceed 42 m/s (the equivalent of a category two hurricane).

I just do not understand what can cause such behavior to be valid for all size and types of trees.

The authors of a recent paper on this subject attribute it to evolution. While winds frequently exceed 30 m/s (126 km/h), they very rarely exceed 50 m/s (180 km/h) in most places. The sweet spot in a tree's ability to sustain winds is between these limits. A tree that is too flimsy will be snapped by a heavy gale, won't live to maturity, and won't spawn offspring. A tree that is too sturdy is wasting precious energy building unneeded structure.
As for why and how, it's a matter of allometry. Trees grow in girth as the age and add to their canopy. Tree allometry investigates the relationship between tree girth at chest height and other features of trees such as height and canopy area. The relationship between girth and canopy area is close to linear.
Another factor is defects, which are places where a tree is most likely to snap in two. The extent of these defects also scales with size. Young trees lose tiny branches; the young tree eventually grows around these, leaving the small defect buried deep inside the tree as it ages. Older trees lose larger branches, leaving behind a potentially larger defect.
References:
Critical wind speed at which trees break.
Trees, regardless of size, all break at the same wind speed. Here’s why.
Urban Tree Database and Allometric Equations.


How much heat was released from the 2019-2020 Australian bush fires? How much heat was released from the 2019-2020 Australian bush fires? And is that likely to have a measurable impact on global atmospheric heat content?

Maybe as a secondary question: How much impact will the CO2 released by the fires have? And (maybe a bit to hard to answer) how much will regrowth draw down?

Right. We can make some estimates of the scale of the problem, but they will come with a healthy margin of error.

If we assume that wood has a calorific value of 18.5 GJ/t (from the phyllis2 database)
The area burned is 18.6 Mha (from Wikipedia here)
The standing volume of material is circa 1500 m3/ha (an educated guess based on Eucalyptus values in Forest Yield)
The density of timber is circa 0.5t per dry m3 (from Forest mensuration handbook)
and only 90% of that material actually burns (a guess)

Then:

There's around 675 tonnes of material burned per ha releasing 12,150 GJ of energy which is equal to 225,990,000 TJ for the total area or 3,587,143 Hiroshima bombs (at 63 TJ each)...

This is a (very) rough calculation, but it gives a scale of the amount of heat released. This is about 10 day's worth of solar constant radiation over the same area, so it might appear in local temperature readings, but bear in mind that 1) there was already unusually high temperatures in the area, and 2) fires like this produce a lot of smoke which will have had an effect on the local radiation budget.

In terms of all that CO2, you can expect it to be reabsorbed by the surrounding biosphere which is described in the impulse response function described in the IPCC AR5 WG1 CH8 technical supplement (8.SM.11.1 Equations for the Global Warming Potential). You can also expect the burned areas to regrow - which will absorb CO2 as well. Depending on rates of growth, I would expect this to take several decades. - but there is a lot of very complex processes, so this is open to a lot of discussion!

Hope this helps.


Temperature differences in sand Sand is granular in nature, which allows air columns to trap in between them. As we know that air is an insulator of heat. So here are my questions:

Does sand maintain its temperatures close to its surface? (Like a conducting shell distributes charge on its surface)

If there were layers of sand, is it possible that in the deeper layers the temperatures remain constant? And only the temperatures of the upper layers changes as the surrounding environment changes?

P.S. If all of this is true is there a particular formula or a study I can use to figure out the temperature difference between the surface and at a depth in a desert?

Yes sand is, on average, quite insulative with the temperature at the surface being rather higher than that at depth when the surface is being actively heated, as by sunlight. The actual degree of insulation depends on at least three factors;

Moisture content, wetter sand is less insulative than dry sand because the water in it's pore spaces conducts heat better than air filled pores would.
Average grain size, courser sand has more pore spaces and thus more of it's total volume is made of air so it's more insulative at a given water content.
Grain size distribution and sorting, sand composed of grains that are all of a similar size will have more pore spaces than sand composed of many sizes of grain. Grains of the same size act like stacked ball-bearings leaving a lot of empty spaces but with larger and smaller grains the pores between the large grains are filled by the small ones leaving little space for insulative air pockets.

Due to the complexity of the processes involved it is very difficult to have any single formula that gives you a measure of sand in general. You may be able to find, or create, data sets that allow you to predict the insulative value and thus temperature at depth of a particular sand under a particular set of circumstances. Generally speaking it's easier to take field measurements, unless there's a really long-term project involved.


Do cloud formations change depending on the season? I'm currently working on some software for cloud masking, and thus far I have only been using satellite data as recent as spring (northern hemisphere). However, I'm wondering if cloud coverage or formations have a noticeable change across different seasons?

Yes. The types of clouds formed are dependent on the profile of temperature and the profile of water vapor. During the summer, there is more radiative flux, which produces more buoyancy. Hence more buoyant clouds (cumulus-type) are formed in the summer than in the winter. Instinctively you may recognize that you get more thunderstorms during the summer than the winter.

Kelvin-Helmholtz wave clouds usually need different densities of air, typical of an inversion. This is more likely to happen during cooler seasons (Fall, Winter, and Spring).

Also, freezing fog is inherently more common in the winter than the summer.


How much atmoshphere is there compared to land and water We know our earth has 71% water and 29% land, but compared to that land and water, how much air do we have in our atmosphere?

I mean:

How big is our atmosphere
Is there any increase or decrease in the amount of atmosphere over time
Is there any change in percentage of oxygen over time

71% of Earth's surface is covered with water and 29% land.

Thinking in that regard, that's saying that on 29% of Earth's "surface" locations you have land below your feet, and in 71% of the locations, you have water.  So to continue in such terms, you'd then ask... ok, what percentage of Earth's surface locations would have air above them!?!  Well that's all of them.  So to if you're comparing it with those percentages, I guess you'd have to say it's another 100%.  Or, if we put them together into a full 3-dimensional surroundings at the surface, well it'd basically be 50% air, 36% water, 14% land.

But to compare how much of each there REALLY is, you need to include depth, getting some sort of 3 dimensional understanding of it.  But the picture that reveals is certainly not the picture we are used to from daily experience.  From the values I was able to find:

In terms of the room each takes up, the volume:

Surface water (oceans+lakes+rivers, glaciers, etc) is 1.4 billion km³
The inside of the Earth is about 1 trillion = 1000 billion km³
For the atmosphere, as mentioned in comments, it's a little more difficult, as the gases only gradually give way to space.  You find less and less gas as you go up, but there's no set spot where there is none, as some tiny amount is always floating off into space.  So where do you draw the line?  A commonly used boundary between the atmosphere and space is the Karman line.  This would lead to a volume of 53 billion km³ (using Earth's radius = 6371 km).  Note that only about half of that is in the troposphere and stratosphere, which are perhaps the familiar zones of the atmosphere where weather and the ozone layer (and 95% of air molecules) reside.

To compare these directly, the volume of land is 20+ times larger than the atmosphere (or 40+ times larger than the troposphere+stratosphere), and 750+ times larger than the Earth's water.

Or as percentages, the volume is:

Land 95.3%
Air 5.6%,
Ocean 0.1%

Another useful way to look at is mass.  In terms of how much mass there is of each (from NASA):

Atmosphere: $5.1\times10^{18}$ kg
Hydrosphere: $1.4\times10^{21}$ kg
Geosphere: $6.0\times10^{24}$ kg

So there is 500+ times more water than air... and 4000+ times more "land" than water.

Or in percents, the mass is:

Land: 99.98%
Water: 0.02%
Air: 0.00008%

You could also look at the comparison in other ways, such as with the number of molecules.  But to save time, the answers will still typically boil down to the same idea: though land is the least of what we see around us on the surface (if you're a true global traveler), it is by far and away the greatest part of our planet overall.

One final visualization that looks interesting is considering if we made giants balls of the air and water at Earth's surface... they'd actually be about the same size...  and nowhere close to the size of Earth (and that's even neglecting the fact that for fair comparison, the Earth, if somehow all of it could be brought to surface conditions, would be even larger due its current internal compression).

As to whether the amount of oxygen is changing, remember no element can be created or destroyed (aside from nuclear processes).  So the only way oxygen can change is if it is tied up in a compound or is removed into the ground or space.  In our lifetimes, there is very insignificant change overall, though it sounds like a notable amount is being used up each day in combustion reactions (see the part about oxygen depletion further down) [oxygen decreases from that, but since carbon dioxide has more mass, the overall atmospheric mass actually increases, just not the stuff you can breathe!].  If you're looking for a much longer history, it appears this Britannica article gives a more thorough discussion of the factors in play and some of the changes that have occurred.

As to the mass of the atmosphere over eons, I naively thought maybe less would be known about that... but articles in Scientific American and Nature both hint the atmosphere was at much different pressures once upon a time (albeit reaching conclusions in opposite directions!)  Such changes in pressure would likely come with large differences in mass and/or volume of the atmosphere as well, but until someone shows me otherwise, those estimates would seem to be quite speculative.

And if we're going that direction, maybe we should just turn to What-If XKCD!


Results of large woody debris in river/lake In the following questions I am wondering how large woody debris and/or submerged trees enhance river or lake environments.  Also I am wondering how they are detrimental to humans.

I know that large woody debris and submerged trees are commonly found in rivers and lakes. They may be present by a result of flooding, logging, bank erosion, forest fires, beavers and many other causes.

I am not sure how they would enhance river or lake environments.  Clearly beavers could use them to build dams but how is this good? Is there any other ways they benefit?

Also, how are they detrimental to humans?  Might they potentially hurt the ecosystem present in the water, which in turn may hurt humans if they are using the ecosystem for resources?

Depending on the fauna within the rivers and lakes, submerged trees can be like reefs in oceans. They provide protection for fish and other fauna and they can also act as nurseries for certain types of fish.

Submerged trees can sometimes be snags in waterways which increases the difficulty in navigating waterways, particularly for larger boats.


coriolis force in atmospheric/ocean modeling The Coriolis force is not a real force, but depending on the reference system and how it does refer to an inertial system. Could this Coriolis force as widely used in atmospheric/climate modeling be replaced by an explicit force eg from sun gravitation and would this give the same results?

Here are your choices with regard to modeling the atmosphere. There aren't many, and only one of them makes sense.

Model the atmosphere from the perspective of an inertial frame of reference.
Good luck with that! As an advisor told me decades ago, "Name one!" It's certainly not an Earth-centered frame; the Earth is orbiting the Sun. It's certainly not Sun-centered frame; the Sun is orbiting Jupiter, Saturn, Uranus, and Neptune. It's certainly not the solar system barycenter (center of mass); the solar system is orbiting the Milky Way. The Milky Way barycenter? Nope. The Milky Way and the Andromeda galaxy are accelerating toward one another. No matter how far afield we look, we see gravity (and even further afield, metric expansion of space) that hides this inertial frame from us.
Use a non-rotating frame centered at the solar system barycenter.
The International Celestial Reference Frame is one such frame. This is more or less a constructible frame. Here we either ignore or account for the acceleration toward the center of the Milky Way, the Andromeda galaxy, and stuff further afield. It does makes sense to ignore those extraneous accelerations; they are very, very tiny, and the variation across the solar system is tinier yet. There's another issue with any such construction. The ICRF almost certainly is rotating. The predecessor of the ICRF, the J2000 frame: Scientists now know it was rotating. The same goes for the predecessor of the J2000 frame, the B1950 frame. In fact, scientists know the ICRF is rotating. The ICRF has been upgraded to ICRF version 2.0. And that too is rotating. Scientists just don't know how much.
Use a non-rotating frame centered at the Earth's center of mass (aka Earth-centered inertial).
Even if the ICRF was perfect, there is no way one can reasonably model the Earth's atmosphere in a computer program from the perspective of such a frame. The length and velocity scales needed to properly model the atmosphere and the length and velocity scales using a solar system barycenter frame just don't match. Oil and water. Even worse, it's a Sesame Street moment! ("One of these things is not like the others, One of these things just doesn't belong.")
The thing that doesn't belong is the solar system barycenter. The only reasonable way to model the Earth's atmosphere is to use an Earth-centered perspective. Now a computer program is starting to have a chance to represent the atmosphere, and do so in a way that is computationally feasible. An Earth-centered frame is accelerating, but we can handle that. We can pretend that $\vec F=m \vec a$ still applies. This result in fictitious tidal accelerations. It's not a problem. Physics still works.
Use an Earth-centered, Earth-fixed reference frame.
A problem remains with the Earth-centered inertial frame described in option #3. The Earth, the atmosphere, and the oceans are rotating, and at different rates. This means that "starting to have a chance" was a bit overoptimistic. It makes much, much more sense to use a frame that rotates with the Earth. This adds even more fictitious forces, the centrifugal and Coriolis forces, but once again, that's not a problem. In fact, this simplifies things to the point where meteorologists do finally have a chance to represent the atmosphere in a way that is computationally feasible.

Option #4, the one that requires fictitious third body forces (aka tidal forces), fictitious centrifugal forces, and fictitious Coriolis forces, is the only option that makes a bit of sense from the perspective of modeling the atmosphere.


can wet winters require more home heating than colder winters, in same place? This winter in UK has been wet and windy but rarely below freezing. Last winter was colder with snow but less rain and wind. My storage heating seems to need to be set higher this year. I suspect the wet external walls of the building are chilled more with the wind. Or maybe more evaporation of wet external walls chills the building. Or maybe more cloud cover means less solar radiation heating the building. It's timber frame brick clad building with what I assume is reasonably ok cavity insulation.

This probably has less to do with the rain and more to do with the wind. The wind helps move the colder air that is outside into your house more easily because there is more force being exerted on your exterior walls and therefore cooler air can work its way through any small cracks. Sorta similar to the wind chill being colder on windier days. The lessened amount of sun also comes into play as even in the dead of winter it helps warm surfaces, even just a tiny amount.

Welcome to the Earth Science exchange!


Are Earth´s interannual global climate variations affected by other bodies in the solar system and their evolution? Are fluctuations like El Niño and La Niña entirely independent of outside influences such as the gravitational effects from other planets, variation in solar output, etc?

Short answer:

There's probably very little effect, but "entirely independent" is another matter entirely.   There might be some small effect on a year to year, or, for sake of argument, 12 year orbital period of Jupiter.

Long answer.

The precise cause and predictability of (El Nino/La Nina and Neutral), or, lets call it ENSO remains inexact and it's at best, a complex combination of causes and feedbacks.  I'm not precisely sure if it's simply complicate or there are still some unknowns that make any kind of longer term prediction very difficult.  I suspect there's still some unknowns and uncertainty in the longer term causes of ENSO.  This is a pay article, in the summary it says.

  Year-to-year ENSO variability is controlled by a delicate balance of
  amplifying and damping feedbacks

The immediate cause for ENSO seems to be weakening or strengthening of easterly, equatorial, Pacific trade winds.   This makes El Ninos, La Nina's or "Neutral" predictable up to several months in advance but they remain very hard to predict further out than that.

ENSO Explained here with pictures.

and while I generally hate the website, Wattsupwiththat, if you ignore their climate model discussion, their trade wind article is pretty good and the picture below gives a good summary of why trade winds control Pacific surface temperature.

Also, just to clarify "Easterly" winds blow West.  The term means the winds come from the East, just as Northerly winds blow south.   That's why the diagram has easterly's blowing towards Indonesia.

The next logical question is, what causes trade winds to weaken and strengthen and as noted above, that's complicated.  This article says the El Ninos occur every 2 to 7 years, which, while generally cyclical, is a pretty irregular period.

And This article describes the cycle as "flipping and flopping"

Wikipedia touches on the cause of trade winds, but not on the precise mechanisms which strengthen or weaken them.   If the planets, presumably Jupiter being the primary one, has a significant effect, then it's 12 year orbital period should be have a detectable effect and I've never read anything to suggest that it does.

Jupiter does, very slightly affect Earth's orbit and Earth's orbit affects Earth's climate but the effect is small on a 12 year (1 Jupiter orbit) basis.

Earth, relative to the sun, is basically in the same position every season.   Jupiter moves more slowly, so for practical purposes it can be viewed as relatively stationary.    When the Earth is behind Jupiter, it moves through it's orbit a little faster.   When it's ahead of Jupiter, it slows down a little bit.   Also, Jupiter has a tidal effect, where, Earth's orbit stretches in the direction of Jupiter.   These kinds of changes in orbital speed were observed in Uranus and lead to the discovery of the planet Neptune.  For similar reasons,  Jupiter does have an effect on Earth's orbit depending on which side of the solar system it's on, but the effect is small.

I'll skip the math cause I don't do it well enough and it would get long and ugly, but a rough calculation puts an upper limit of the Jupiter effect on Earth's climate as 1/20th of 1% of solar radiation over a few years and then a return in the other direction a few years later, and that's peak season variation, not over a full year.   If winter gets 1/20th of 1% less radiation from the sun, or Summer, 1/20th of more is 1/20th of 1% colder might have a small effect, but not a big one.   That's less than the TSI variation of the sunspot cycle which peaks at about 1/10th of 1% and lasts longer.

I've never heard it argued that Sunspots drive the ENSO cycle, though there is probably some small effect with that too.

Of-course, over much longer periods, Jupiter and to a lesser extent, Saturn likely do effect Earth's ENSO cycle, because Jupiter and Saturn drive Earth's Milankovich cycles, but those happen over periods of 20,000 years and up.   I don't see any way that the 12 year Jupiter orbit has anything more than a very tiny effect.


Is there a widely accepted reason for the formation of tafoni? Expansion of tafoni seems to be based on weathering (seems reasonable enough.) But what creates them in the first place? There are a number of explanations online (Wikipedia lists eight plausible causes!) Many websites trying to give a simplified explanation simply say "salt weathering", but from a brief search it's clear that salt weathering is not always the cause of tafoni [0]. They develop on a wide range of rock types, from granite to sandstone to tuffs and conglomerates, and in many situations where they'd be expected to develop they don't.

From what I can tell, they seem somewhat mysterious, and there are explanations that make sense in some cases but not every case of tafoni is well explained. Is there a widely accepted explanation for the formation of tafoni?

Picture of tafoni (Martin Sharman, Wikipedia):

[0] for example: page 75, Arid and Semi-Arid Geomorphology, Andrew S. Goudie

I had a good geomorphology teacher. He was so good that I bought his book, published on Prentince Hall at 2008. He is an aged an experimented geomorphologist, so I totaly trust there is not an agreement about the physical origin of tafonies (or at least there wasn't an agreement at 2008 when his book was published).

  "Its origin [tafonis] is controversial (Twidale and Vidal Romaní, 2005). Some authors differentiate between wall tafonis and basal tafonis, linked to the processes of basal undermining (Smith, 1978, Bradley et al., 1978). It is agreed that the dominant processes are those related to the movement of water with salts close to the surface, which correspond to haloclastism and wetting and drying. Thermoclastism, cryoclasty, dissolution of carbonated cements and wind erosion are also mentioned (Evans, 1969-70, Mustoe, 1983, Young, 1987, Robinson and Williams, 1992). In addition to these subaerial processes, some taphonis can be generated by weathering under the soil surface and subsequent exhumation by erosion (Dragovich, 1969)."

  Source: Geomorfología, Prentince Hall (2008), page 152.
  Translated from spanish by Google.

-Gutiérrez Elorza, M. (2008) "Geomorfología". Ed Prentince Hall.

-Twidale, C. R.; Bourne, J.A., y Vidal Romaní, J.R. (2005): "Beach etching and shore platforms" Geomorphology 67, 47-61.

-Smith (1978) "The origin and geomorphic implications of cliff foot recesses and tafoni on limestone hamadas in the northwest Sahara" Zeitscrift für Geomorphologie, 22, 21-43.

-Bradley, W.C.; hutton, J.T., y Twidale, C.R.(1978). "Role of salts in development of granitic tafoni, South Australia". Journal of Geology 86, 647-654.

-Evans, I.S. (1969-70) "Salt crystallization and rock weathering: a review" Revue de Géomorphologié Dynamique, 19,153-177.

-Mustoe, G.E.(1983)"Cavernous weathering in the Capitol Reef Desert, Utah" Earth Surface Processes and Landforms 8, 517-526

-Young, R.M. (1987) "Salt as an agent in the development of cavernous weathering" Geology 15, 962-966.

-Robinson, D.A. Williams, R.B.G.(1992) "Sandstone weathering in the High Atlas, morocco" Zeitscrift für Geomorphologie 4,413-429.

-Dragovich, D. (1969): "The origin of cavernous surfaces (tafoni) in granitic rocks of Southern Australia". Zeitscrift für Geomorphologie 13, 163-181.


What is the difference between Saprolite and Regolith? Saprolite and Regolith both imply loose material, is one a subset of the other how can I differentiate them ?

In short, saprolite does make up the regolith. Saprolite is a term for in place, weathered rock. Regolith encompasses all the heterogeneous components of loose material covering the solid rock of the earth or other planetary bodies.


Why does air subside in the Eye - the lowest pressure area of a tropical cyclone? A low pressure area is associated with rising air while a high pressure area is associated with subsiding air. The best explanation I could come up with is either the cyclone is an exception or the above associations are not an absolute rule in the first place.
However, none of the articles I read provide an explanation on this phenomenon, indicating that I am missing something trivial.
Could anyone shed some light on this? I would appreciate a layman explanation.

I will just talk about an already formed tropical cyclone. Converging winds spiral in (counterclockwise in northern hemisphere) over the warm ocean waters towards the central low pressure area of the eye.

At the eye they spiral upwards, taking the warm, moist ocean air high into the atmosphere. As it reaches cooler elevation, the air releases its latent heat, adding more energy to the storm.

So you have a tremendous volume of air converging from 360 degrees around the hundreds of miles of the storm, all converging on the eye and spiraling up with an intense updraft, creating a very low pressure near the surface in the eye/core.

High above the eye wall this upflow begins to spread out. This permits cool dry air above the eye to sink down into the central core of the eye (that is why the eye is often clear and cloud free).

So why is the hurricane core/eye low pressure when there is cool dry air subsiding down into the core/eye?

Soundings taken within the eye show a low-level layer (at surface) that is relatively moist with an inversion above, i.e., it appears that the sinking cool dry air (which warms somewhat as it is compressed in descent) never reaches the ocean surface, but only reaches within 1 - 3 km (1 - 2 mi) of the surface. See, among other sources, http://www.aoml.noaa.gov/hrd/tcfaq/A11.html.


What is the significance of amphidromic points related to tides? On reading about tide formation and the role of moon's gravitational force, I came across the term amphidromic point. Could someone please elaborate this concept?

This will be a bare-bones answer, because I don't have time to do more. If somebody wants to do a more complete answer, with a figure or two, feel free; otherwise I'll try to come back and expand this in a day or two

Good question! If one is familiar with the simple explanations of tides (bulges of water following the moon around the earth), this doesn't make sense.
However, that way of thinking only gives us equilibrium tides, which are what we would have if Earth was an ocean planet. In reality, we have continents, and they get in the way.

Most tidal movement actually consists of water "sloshing" around ocean basins - e.g. across the Atlantic between North America and Europe. But because the planet is spinning, Coriolis force applies and tends to impart rotation to straight-line movements. This results in the tide tending to form two-dimensional waves that go around ocean basins in a roughly circular pattern. You can get a similar wave going in a hot-tub, with a bit of effort! At the outside of the basin, where the wave meets the land, the amplitude tends to be the greatest - but in the middle, it's close to zero.


Fine particulate matter - Why the lack of attention? What can be done to tackle it? If fine particulate matter as a pollutant from industrial or natural sources (e.g. a desert) can be such a cause for concern in terms of (further) desertification as well as health impacts, is there a reason why there does not appear to be much action to control or solve it?

For instance - you will sometimes see construction sites required to use a canopy and/or water to localize the spread of fine particulate matter to a particular site, and forestation projects can serve to anchor some land in the face of advancing desert boundaries - but such applications seem limited in their enforcement.

What more could be done to control and combat fine particulate matter (and perhaps avoid warmer, drier countries and regions from becoming dust bowls)?

There has been some considerable attention, it is not that factor that is hampering more coherent action, it is a lack of full understanding of the fine particulate matter itself - allow me to explain.

A lot of the reason why there has only been largely piecemeal approaches to combat Fine Particulate Matter, globally speaking, is due to the incomplete understanding of the aerosols and their dynamics themselves.

Having said that, there are different strategies to combat fine particulate matter (FPM). But, first, a definition - the United Nations Environment Program (UNEP) page Pollutants: Particulate matter (PM) states:

  PM 2.5 refers to particles with a diameter of less than 2.5 microns. These are usually called fine particles and contain secondary aerosols, combustion particles and re-condensed organic metallic vapour, and acid components. Fine particles can reach all the way down to the alveoli in the lungs.

The inclusion of secondary aerosols, combustion particles (e.g. soot) and recondensed organo-metallic vapour can and does complicate attempts to mitigate the effects once released and would also complicate attempts to prevent the release.

It could be argued that the ultrafine fraction at 0.1 microns and less could be included under the FPM umbrella; however, as stated on the UNEP page, these are still the focus of extensive research.

There are several documents calling for the control and providing practical strategies by governmental organisations, one such document is the US EPA's Controlling
Fine Particulate Matter
Under the Clean Air Act:
A Menu of Options (2006), in which it is acknowledged that

  The chemistry and physics of PM2.5 formation in the
  atmosphere is incompletely understood.

also, in a practical sense,

  In a perfect
  world, control-efficiency and cost-effectiveness data would
  be at hand; however, it is not consistently available.

and also in a scientific - practical sense:

  there are important distinctions
  between filterable and condensable PM2.5. Further, some
  methods used to measure PM emissions reflect only the
  filterable components and, to exacerbate the problem, the
  filterable components vary depending on the test method
  used.

The first step in any attempts to mitigate the FPM content in the air is to monitor the sources, flow, composition etc of the particles.  From the EPA document:

  The importance of determining source apportionment
  for ambient PM2.5 in a specific area cannot be overstated;
  developing a cost-effective approach to controlling PM2.5
  emissions sources requires an understanding of the relative
  contribution from local and regional sources. Adequate
  monitoring data are needed to provide insight into the
  composition of ambient PM2.5 in a given area.

A British document Fine Particulate Matter
(PM2.5) in the United
Kingdom (2012), states the reason why action is not happening fast enough reasonably well, with

  The science underpinning the knowledge of PM2.5 is rapidly evolving and
  remains uncertain in many areas. There is a need for rapid translation into the
  policy arena of the newest results and understanding.

The uncertainty due to the varying compositions, which in turn affect how the particles move, how they interact with the surrounding environment suggests that 1 method would not be sufficient, and that more localised methods of control are necessary.

As you suggested, the importance of understanding FPM can not be understated, in epidemiological research Reduction in Fine Particulate Air Pollution
and Mortality
Extended Follow-up of the Harvard Six Cities Study (Laden et al. 2006), there have been found to be a drop in mortality corresponding to a drop in FPM concentrations.


What processes created these apparent topographical anomalies in North California? In the attached topographical map, you can see some strong topographic features in Northern California — elongated foothills below Mt. Tamalpais.  You can also see, circled, some apparent anomalies.  What could account for them?

Tectonic processes and erosion.

Well.....obviously: all surface features on our globe are caused, at base, by tectonics (uplift or subsidence) and erosion (knocking down or burying). To simplify: shifting plates cause mountains to build and basin to form and water falling from the sky erodes the rock and fills valleys with sand and gravel.

That, however, won't explain why a specific mountain will be shaped like a dog biscuit, or why a certain lake will look like a guitar. These are very specific results of erosion and, as such, are controlled largely by the internal fabric of the eroded body.

Water, as we all know, is the most important erosive force on earth and we also know that water will always seek the easiest path to the sea; it's a constant, stream of fine sandpaper always first eroding the softest, weakest spots of anything it touches. This would include the following:

"Soft" rock units like carbonates, shales, and chemically unstable rocks like serpentinites.
Internal weaknesses like fault planes, joints, bedding planes, and folds,

In the area highlighted by the OP, there is an abundance of these weaknesses for water's erosive power to exploit. That these weaknesses occur rather randomly in this area means that there is no specific orientation to drainages and mountain ridges. And this all makes sense given the context of the geologic history of the region.

This area is home to the Fransiscan Assemblage of rocks. These mangled, misshapen, motley group of metamorphosed sedimentary rocks were once part of the accretionary wedge that built up at the bottom of a subduction zone. Tectonic forces bent, folded, cooked, smeared, and finally lifted these rocks, exposing their inherent weaknesses to the erosive power of water. The relatively random nature of these weaknesses results in a pretty random-looking erosional pattern.

Below are a few examples from the SW U.S. of what erosion does to uplifted units that contain regular and ordered weaknesses:


Fix pH Value ongoing with right plant I am a very beginning in planting three.
I sent a ground sample for analysis and one of the results is the pH value of
pH 6.2 in water solution and
pH 4.75 in KCl solution.
I am planning to seed walnut tree which likes most alkaline ground rather than acidic.
One of the solutions for fixing Ph value is to put limestone in the ground but this needs at least 2 years to finish part of the process and also can affect microelements in the ground like Iron or Boron.
Assuming that current pH value is ok to start with planting
I would like to ask if there is some plant that can make ground alkaline and also Walnut friendly.
Or in other words, is there a combination of plants with Walnut that can help each other to use the best from the ground without artificial ground fixing?

A pH of 6.2 is pretty acidic for soil . A more obvious method to lower acid would be limestone as gravel. And for a fast start ,add lime powder, available at any agriculture supply. Rototilling would be good ,but just sprinkling on the surface would be some help.  You can measure soil pH yourself easily. Put a soil sample in distilled water and shake in a sealed container ( to avoid CO 2 from the atmosphere ) .Then get pH indicator solution from a pet shop ( bromthymol blue ?) and test the water after the soil settles. Aquarium water is routinely tested with this indicator.


Can I regard the grayscale of a RGB color image as a panchromatic image? Here I have a remote sensing dataset with many bands (e.g., blue, green, red, ...), and I use the blue, green and red bands to get a true color image. I want to know if I can get a panchromatic band based on this true color image?
I guess it can be done by displaying the true color image as a grayscale image, then this grayscale image can be seen as a panchromatic image. Or I can convert the RGB format image to HIS format, then the insensity component can be seen as the panchromatic image. I am not sure whether it is right.

The workflow of fusing RGB true color image and panchromatic grayscale image can help understand this question. After converting RGB color space to the IHS space, the intensity component is replaced with the (high-resolutional) panchromatic image, and then the new intensity, hue, saturation combination as IHS are converted back to the original RGB space.


Is altitude of everything decreasing due to sea level rise? We know that sea level is rising, though some people say climate change is fake.

Altitude is defined as the height of something measured from sea level.

Since sea level is increasing, and the heights of most things is not: is the altitude of most things decreasing?

Altitudes are referred to a geoid (an imaginary surface of equal gravity strength), that is chosen to fit the mean sea level. Therefore, if we were to constantly adjust the geoid to fit the rising sea level, all the altitudes would indeed be decreasing in average.

However, it is very important to highlight that "in average" part, because of the rates involved. Let's have a look at the sea level rise rates:

As you can see in the above image (taken from Hawaiʻi Climate Adaptation Portal), the rates of rise are in the order of 4 mm/yr, a value that is small in comparison with other processes that can also change elevations. When you go down to the millimeter-scale, the topography is much more dynamic than you would think, for example:

Post-glacial isostatic rebound: One of the reason the sea level is rising is because the glacier are melting. Mostly from mountain areas. As the glaciers melt, they unload the crust that can be pictured as floating on the mantle (a.k.a. magma at the interior of the Earth), and as any floating object that loose weight, it gain flotation and rises. Typical rates are about 10 mm/yr, but rates up to 39 mm/yr have been measured in heavily glaciated areas. Therefore, most mountains in medium and high latitudes are rising faster than the sea level.
Erosion: Erosion rates are also of the order milimeters per year up to meters per year in river beds and other areas. So, in some areas the erosion can play a much bigger role than sea level when it comes to elevation change. To make it more complex, erosion will also trigger isostatic rebounding, in many case both processes are in balance at large scales.
Deposition: Landforms like stuaries, beaches and deltas, are product of the balance between sediment deposition and erosion. If the sea level rise, the delta will rise too given enough time. The problem currently in some areas, is that the sedimentation can't quite catch up with sea level rise and coastal erosion.
Tectonic uplift: Tectonics also is constantly changing the elevation trough slow deformation and Earthquakes. Parts of the Himalaya are rising at rates of 10 mm/yr, and large earthquakes can produce sudden elevation changes in the order of a few meters.
Tectonic relaxation: As volcanic islands cool down, they sink, Hawai'i is doing so at rates of about one millimetre per year. And geologically young volcanoes are sinking due to the extra weight its formation put on the underlying crust.

Therefore, to say that the elevation of something specific is changing because of sea level rise is not something easy to backup, as there are many other processes to take into account. Scientist make fairly complex models to figure out which areas will actually experience flooding due to sea level rise, and unfortunately, so far they have found that there are many highly populated areas that will face big challenges for that reason.


Algorithmically Determining the Rainy Season I have historical precipitation data for hundreds of cities around the world. I would like to algorithmically determine when the rainy season (if exists) is for each location. Are there any algorithms out there that can determine this based on the monthly averages alone?

Some problems that I envision are:

Having a lot of rain is not enough. Many places in south east asia have very heavy rain falls for a couple of minutes a day, but it still is not necessarily considered rainy season.
Is it better to say that if the weather is x standard deviations above the average precipitation that it is rainy season or use a moving average?
Any other ideas, links, etc?

I'm brand new to the field so help and an open discussion would be appreciated.

This is an interesting statistics problem.  I would do this for starters.  Take all the years of data and calculate average rainfall amounts for each day of the year.  If you're looking for the rainy season, I would use maybe a 30-day moving average on this, but make sure that the average can wrap around Jan 1.  Once you have these values -- 365 values for each site -- I suggest trying a few things:

1) Try out the standard deviation approach.  It's easy to calculate, so you should be able to play around with the particular number "x" in "x standard deviations above the mean".  If it works for you, there's no reason to make it harder.

2) Using "x standard deviations above the mean" really just means that you're looking for a certain value of the cumulative distribution function (CDF) of rainfall.  Instead of using standard deviation, you could calculate these CDFs for each site from those 365 values, and pick the 75th percentile or something.  I'm still thinking through whether this would guarantee that you get a "season"; it's possible that the top-percentile values of the year are nowhere near each other.

3) Plot out a few distributions for key sites: dry midlatitudes, wet midlatitudes, polar, tropics (monsoon-dominated).  If these PDFs look pretty similar, you might be able to figure out a sensible approach.

I think the key difficulty here isn't going to be that different places have different total rainfall, but that different places can have rainy seasons of different lengths.  If the season was always 30 days, I think this approach would be fine.  I'm really interested in seeing those CDFs just to see how different they are.

Let us know what you come up with!


What determines the spatial resolution of a study? This might sound like a silly question to many of you, but I am addressing the comments of a referee regarding a study I'm trying to publish and I remained a little puzzled about this issue.

Let's assume I have set up a simplified model that processes biophysical and socioeconomic data to analyze an issue attaining water management. Biophysical data (mainly topographic, climatic, and hydrological) are available at relatively high resolution (0.25 or 0.5 degree), while socioeconomic data are available at country resolution. The model was set up to run at gridcell resolution (0.25 degree), but, of course, all the cells of the same country share the same values of the socio-economic variables. However the process is run for each individual cell and the results are different from cell to cell, even in the same country.

In my manuscript, I claim that the resolution of my study is a quarter degree. This sentence is contested by a referee that states: "The resolution of the results of a given study is actually defined by the coarsest dataset that the study uses (not the finest). Part of the data used are available only at country level, so the spatial resolution of their results is at that level, not finer."

Now, I understand that coarse biophysical data (precipitation, temperature, land use, ....) should be eventually downscaled to be used in a gridded modeling approach, but what about variables like "corruption" or "quality of the institutions"? Does a downscaling of such variables make any sort of sense?
What finally determines the spatial resolution of a study?

Thank you

It sounds to me like the reviewer is fixated on a 'rule' they encountered in grad school, but the rule ignores some real-world nuance (as rules do).

Quick caveat: my answer isn't definitive, it's more of an opinion, but it was too long for a comment.

It seems intuitively true that some phenomena just are smooth, so the resolution of the data is not the limiting factor in an analysis of resolution. I'm thinking of things like maps of average seasonal air temperature (say). Certainly, you can combine that with higher-resolution data and still claim to have a high-resolution analysis.

Other data may not be implicitly smooth, but it's interesting to aggregate the data for the purposes of generalization.So the quality of academic institutions obviously varies on a per-institution basis (or per teacher, if you want to get silly about it), but it would be crazy to interpolate data like that and, since it's reasonable to think there might be national-level influence (e.g. in funding for education), it only makes sense to aggregate it that way. Again, I think it's reasonable to argue that you can combine data like this with higher-resolution data and have a high-resolution analysis overall.

Still other data may simply be oversmoothed, or smoothed on the wrong basis. Temperature data by country, or geological data on a 100-km grid... Then I'd say those are limiting the resolution of any analysis you do.

In conclusion...

I can't think offhand of a way to formalize all this, and don't know of any research around it (though I'd bet on its existence). Assuming you don't want to go down the research rabbit hole, or have a protracted argument with the reviewer, my advice is to respond to the objection by using more specific language. Instead of generalizing, specify the resolutions of the various datasets involved and mention where it might be possible to improve the resolution.


What is the lowest latitude for which if the ideal solar energy received each day for a year is graphed, the graph would contain one peak? I asked a question with the same meaning on Quora, but it seems no one got it, so I'm asking it here with a very different wording. I'm actually not sure if this would belong here or on the Astronomy stack exchange, as though it deals with the Earth, it is an extremely pure question with almost nothing to do with its atmosphere or complicated innards. Real-world topographic and atmospheric moisture conditions that may affect the results are to be ignored.

For all latitudes outside the tropics, as I'm sure we know, the summer solstice is the date where the sun culminates the highest in the sky, having the highest solar angle and insolation. This angle is 90° at the tropical circles. Closer to the equator, this 90° angle is experienced in 2 Lāhainā noons moving further from the solstice the lower the latitude is until reaching the equinoxes at the equator.

However, at all locations except the equator, the summer solstice is the longest day of the year and the winter solstice the shortest. Hence, down to a certain latitude within the tropics the summer solstice should still experience the most total solar energy, as the effect of the longer day would be stronger than that of the lower solar angle. As you get closer to the equator, the day length gets more consistent and the angle at the solstice becomes still further from that at the subsolar point, until eventually the solstice no longer receives the most total solar energy and two "humps" emerge.

So, what is that latitude?

Note: This answer can depend on if the eccentricity of the Earth's orbit is taken into account, in which case the values for the Northern and Southern hemispheres will be different. Answers may choose to take this into account or not (ideally I'd like both).

Any area south of the northern polar circle will have one peak per day,and the same goes for the southern polar circle any area north of this will have one peak per day,the polar circles is at 66,33 north/south.

The areas whitin the polar circles will have only one peak per year but it will last for half a year.

A solar panel will only produce significant power for a maximum 12 hrs even in the area of the midnight sun,This is due to the very low angle of the sun during the "night",or at the poles it will produce energy for 24 hrs but due to the suns angle a solar panel will produce a lower level of power than if the solar panel was at the equator.

Solar panels will be most effective if placed close to equator and less effective as you move away from equator,The suns rays have to penetrate less atmosphere at equator and a lot more closer to the poles.


Leaching Requirement How can we determine supplemental irrigation needed to reduce soil salinity knowing ETP of a crop and the annual precipitation?

Here is some supplemental material for the good answer above. It won’t let me comment, http://www.fao.org/docrep/x5871e/x5871e04.htm


Estimating fracture pressure (looking for literature to support) I am trying to estimate fracture pressure of a reservoir when applying injection.

I keep reading fracture pressure=reservoir pressure+2000psi
or fracture pressure gradient is 0.7psi/ft, but I can't find anything to support those values.

Can you provide me with a literature or a better way to calculate the fracture pressure?

fracture formula What is the method of injection and fluid you are using? Apply a leak off test to the formation after drilling out casing shoe and your 5-10m into open hole. I’ve attached two links that may be helpful.                           formation fracture pressure
                         a list of methods
There are also plenty of apps for you’re phone that you may find useful. Search “drilling formulas”

Basic frac graduent is 18kpa per meter there fore at 1000m it would take 18000kpa pressure  more or less to fracture a zone.
In psi it is .8 psi per ft of vertical depth.
Usually it takes a higher pressure to frac a formation but feed rates are much lower.

Kind regards
Jeff B.


What is the best way to mount white mica separates? I have detrital mica separates that I would like to mount in EpoThin resin for microprobe analysis and I would simply like to know the best method for mounting them. With zircons you can mount on double sided tape and then simply pour the resin over them. But with micas I am worried that they will not peel away easily from the tape once the resin has cured. I am also concerned about polishing them. Any advice would be much appreciated.

I had asked the same question on ResearchGate and got some good feedback. So anyone who is interested in this kind of methodology can follow the link below.

https://www.researchgate.net/post/What_is_the_best_way_to_mount_white_mica_separates


Can cooled/hardened lava rock return to a molten state? Can lava that has cooled to a hardened state be returned to a molten state by, say, a new river of molten lava flowing over it - like re-smelting iron? If you threw a lava rock into the mouth of a volcano, would it remain in its solid state or would it melt and become part of the cauldron of magma?

Yes, at least partially.

It is important to remember that a "rock" usually does not have a single melting point. It melts over an interval. Igneous (magmatic) rocks are made of combination of minerals (for example, quartz, olivine, pyroxene, feldspar) that each will melt at a different point. When a rock is heated up, the minerals with the lower melting point melt first, followed by the higher melting point minerals with progressive heating.

Some rocks are composed mostly of easier-to-melt material (for example the stuff that came out of Mt. St Helens, mostly granitic composition) and others are made of harder-to-melt material (for example Hawaiian basalts). Taking a a granite and throwing it into a basalt will melt most of it for sure, if not all. Not the opposite though.

Even if you do not completely melt the rock, you will disintegrate it enough that the remaining harder-to-melt minerals will just drift away and mix with the lava, making it impossible to distinguish the original rock any more.

Likewise, when hot lava flows on easy-to-melt material (for example clay-rich soil), some of it will melt or vitrify (turn to glass).

I will finish by emphasising that all lavas, every single one of them, were originally solid rocks that melted at depth by some kind of process. So yes, it is possible to melt rocks.


What allowed the Himalaya to become so high? Of course the mountains were caused by moving tectonic plates. But in case of the Himalaya mountains was the speed of the plates just higher so more energy got 'into' the mountains. Or was the continental plates just slightly more loose on the plates? Or did the plates just submerge more, if so what caused that? Or....

It mostly has to do with the type of convergent boundary the  Himalayas are, continental crust to continental crust. Most convergent boundaries are oceanic to continental or oceanic to oceanic. In both cases there is a dense oceanic plate that can get subducted. But in a continental crust to continental crust collision neither can really dive under the other and get reworked*, since both are low density, thick, and roughly equal in density, so they just compress together like pushing two wads of clay together. They build both up and down since they sort of float on the rock below. Think of it kinda like a geologic iceberg, it is too light to sink. All compressive collisions  thicken like this to a lesser extent, due to the compressive forces, it is just far more intense with continental to continental collisions because there is no other outlet for the energy but compression because all the material involved is to light to be subducted. .

the Eurasian and Indian plates are both large continental plates so as long as they are getting forced together they can only get thicker and thicker. This is the only boundary like this on earth right now, so it seems weird to us, but this type of collision has happened before they are just rarer.

*sometimes one does go down more than the other but it does not get reworked, they just get fused together in a lopsided fashion.


How does Vertical Electrical Sounding Work? I recently conducted a brief training exercise with VES equipment, although it had to be called off due to rain. I can't help but wonder about the basic physics of it, why is it that increased distance between the electrodes results in an increased depth of investigation? See the image below for an example, see the difference between A1 and B1, vs A2 and B2

The diagram is perhaps a little mis-leading.
Think of the ground/rock between the electrodes as a big resistor. The surrounding rock can be modeled as a set of parallel resistors. Most of the electrons will take a direct straight line route between the electrodes, but some of them flow through this surrounding rock, so increasing the current and reducing the measured resistance.

In theory this parallel resistor model could go off to infinity (or the other side of the Earth), however if the probes are close together, then the resistance for the electrons to go down and then back up counteract any reduction in overall resistance. Yes there's a contribution but it is vanishingly small.

Move the probes further apart and rock of varying depths (and widths) can add effective current carrying capacity - as per the diagram. Just remember that for the outer probes, the electrons are also moving horizontally, as well as in the deeper tracks.

So what you measure is a composite effect of many depths. By moving the electrodes further apart, you can sample deeper, but you are still measuring a composite resistance.

This makes interpretation difficult! In fact, the only time I've seen or known a Schlumberger or Wiener array being used, was in a student demo that I participated in.

Resistance is much more practical in the archaeological domain. Here, two electrodes are left at a base station, and two are moved around in a sampling frame (rather like a zimmer frame or walker). Then you are sampling shallow variations localized to the frame-mounted electrodes. Eg. shallow stones, charcoal, etc. The resulting images are much easier to interpret and often appear on TV shows like Time Team, Discovery Channel, etc.


Can winds also arise due to a statistical probability that more air molecules suddenly gets an equal direction? Although air molecules have an average speed of about 1,500 km/h if there is no wind the air would stay still. The reason for that is that the directions of the molecules cancel each other out.

But is there a probability that wind arise because a majority of the molecules get the same direction? Or is this only theoretically possible?

This is perhaps more of a physics question than an earth science one. Thus, answering with the caveat that I am not a practicing physicist:

Yes, it's possible. But it's VERY unlikely. Without doing the maths, I'm guessing "probably won't happen in the lifetime of the universe" unlikely. The reason for this is that there are a LOT of molecules in any macro-scale parcel of air, and a huge majority of them would all have to randomly move the same way at the same time. (plus, I'm guessing there are some Newton third-law, ie action & reaction, reasons why a spontaneous mass movement wouldn't really work)


Will photosynthesis based carbon sequestration always be more efficient than other chemical means - in terms of rate? There seem to be many ideas for carbon sequestration. The problem with anything electrochemical, is that unless it is solar-based, you're putting carbon into the atmosphere at probably a great rate than you're taking it out.

One interesting one seems to have been dumping limestone into the oceans, but calculations indicate that this will be too slow in terms of reaction mixing time, given our current CO2 emission rate.

One wonders if you could build an extrochemical device based on solar power - to pass carbon dioxide through water, and create an ionic reaction that would lock up the carbon. But that would just be a less efficient version of photosynthesis.

My question is: Will photosynthesis based carbon sequestration always be more efficient than other chemical means - in terms of rate?

Edit: A helpful question has been raised about what efficient means. It could be land use or energy consumption or rate. I meant rate.

Rate.. no.

Brute Force

We can treat this as an industrial chemistry question. The brute-force method for carbon sequesteration is simply:

Extract CO2 from the air (using the acid/base chemistry, Sodium Hydroxide will scrub it as fast as you can supply air)
Reduce CO2 to elemental carbon and oxygen. The exact details are not actually important - that's one for the industrial chemists - just the concept that it would take a LOT of energy. Basically as much energy as we currently get from fossil fuels, and then some, to extract and reduce at the same rate.
Store the carbon somewhere safe, where it isn't going to catch fire. As long as it doesn't, it's stable on geological timescales.

The rate of this process is dependent on how much energy you are prepared to throw at it. A fleet of several thousand nuclear reactors running 24/7 on this problem would do it.

Burial

Well, brute force sounds a bit expensive.. so we can try the approach mentioned by Jack R Woods. In this case, we capture CO2 (this still takes energy, although not much in theory), and pump it into thick basalt formations such as the ones in Iceland. Many flood-basalt igneous provinces have the combination of low-silica rocks and high porosity that are ideal for this kind of sequestration. The rate is limited by how fast you can capture CO2 out of the air.  You could imagine using a Solar Updraft Tower - this would give an air flow that you could extract CO2 from, and provide power for the process. If the reaction goes as planned, it's safe on geological timescales.

The problem is, as ever, getting enough resources to build these things on the scale required.


Need help identifying this rock that my grandfather found in or around Hot Springs, AR 75 years ago. PLEASE I inherited this from my grandfather and all i know is that it's very heavy and it appears to have gold content. It's actually just been sitting around my house as a door prop the past 20 plus years. help?

From the looks of it, I would suggest that it is more likely pyrite than gold. However, it is difficult to say without inspecting it in person.


Is it possible to predict the maximum daily/annual tide height without calculating hourly heights? It's possible to predict tide at a given location and at a given time reasonably well (e.g. predicting low tide). And there are tools available that make it possible to do this calculation for any location on earth at any time, such as OTPS.
Given that, it's possible calculate the annual maximum tide by calculating (sub)hourly data, and then taking the maximum. However, this is a pretty expensive way to do things - you're calculating 8.7k heights just to calculate a single maximum, and the calculations themselves are not particularly cheap. This quickly becomes a problem if you want to calculate a lot of locations.
Annual maximum tide is not the same year to year, and from memory, the tides have a long-term cyclic nature of around 18 years (that is the lowest common multiple of the periods of all of the cyclic components).
Is there a way of either analytically calculate the maximum tide height on a given day, or for a given year; or to calculate/estimate the time of that maximum (from which it would be possible to calculate the height)?
I'm only interested in the long-term predictable component of tides - astronomical tides (and perhaps other things, like local orographic effects?). Not interested in storm surge or wave effects, or other things that are hard to predict in the long term.

Tidal tables are regularly calculated by several oceanographic institutes worldwide and handed out e.g. for navigation. Influencing factors (superficially spoken) are positions of celestial bodies like Sun, Moon, Venus, Mars, Jupiter and others, modelling of the propagation of the tidal bulges over the ocean basins, and topography and coastal features to calculate individual heights and, equally important, strength and timing of currents. These calculations are done for certain points of interest, like ports or coastal features or areas that could pose a risk to navigation. It is calculated and published for a year in advance.
Modern electronic equipment displays values directly, else one would have to do it old style and search in the tables for adjacent places and a time interval and do a little interpolation manually.
The tables are usually to the minute, to the tenth of a knot in current, and a decimeter in height, but of course small scale local features and meteorology and weather can have huge influence and significally alter the precomputed values. But weather prediciton has its limits which are days.
Examples for tide tables:
https://www.linz.govt.nz/sea/tides/tide-predictions/how-calculate-tide-times-heights
https://www.admiralty.co.uk/digital-services/admiralty-digital-publications/admiralty-totaltide
You can check tidal figures for individual times and places yourself with the help of a nautical chart viewer (e.g. navionics.com chartviewer, the red diamonds with a T inside), or by buying the tables if one needs a copy, e.g. the ATT. I fear they cost a little something.
All that said, there is the concept of the "Highest Astronomical Tide" HAT, which is part of the calculations. Simply spoken the highest possible tide if all the celestial bodies pull in the same direction. But meteorological influences (e.g. a storm) cannot be calculated beyond a few days.
So, generally, this can not be done with exactness because of unforeseeable meteorological influences. If we ignore these (not advisable for nautical purposes) and for average meteorological conditions, the highest (or lowest) tide for a time and place can be taken from these tables.


Did global temperature increase or drop in the last 2 years (2017-2018)? This website

Climate change global temperature from a governmental organization,
shows 2 graphs , one called "History of global surface temperature since 1880" and the other called "Yearly surface temperature compared to average (1850-2018)" which seems to show global temperature dropped the last 2 years. The second graph shows as source NOAA, NASA, University of East Anglia and the Japan Meteorological Agency. The lines of all of them are going down for the last 2 years.

But for NASA in particular, you have in their official website  Global temperature a graph called "GLOBAL LAND-OCEAN TEMPERATURE INDEX" which measures "temperature anomaly", which shows for the 2 years the temperature going up.

My question is, and even more considering both websites share one of their sources,

Did global temperature increase or drop in the last 2 years?

Did global temperature increase or drop in the last 2 years?

Before I answer the question, I need to add the caveat that climate change does not say that every year will be warmer than the previous one. Events such as El Ninos and La Ninas can make the global temperature spike or drop in any one year. The Pacific Ocean dumps huge amounts of pent up heat into the atmosphere during El Nino events.

2014 saw the start of an El Nino event that briefly stalled but then became one of the largest such events ever observed. The 2014-2016 El Nino made 2015 and 2016 the warmest years on record -- so far. 2017 and 2018 were a bit cooler than 2015 and 2016. They were however warmer than every year on record prior to 2015.

2019 most likely will not be warmer than 2016, but it might well beat 2015 as the second warmest year on record. And that is without the help of a massive El Nino event.


Is soil a renewable resource? My geology textbook tells me that soil is not renewable, and I agree with this, but there was some question in my class as to whether this is true.

Some soils take more than a human lifetime to regenerate.  However, in crop production, it seems as if soil can be regenerated with additives.

In the scientific community of soil scientists, is soil considered a renewable resource by most of those scientists?  Is there strong evidence to support this?

Soil is an interesting case because although it is non-renewable (at any useful rate) as a 'bulk material' once removed from the ground, the nutrient content of soil can be renewed with fertilizers.

What a soil-scientist would understand as 'soil' is ultimately produced from the physical and chemical breakdown of solid bedrock at the base of the soil horizon. The rate at which this happens for natural soil production can vary substantially depending on the climatic conditions and other factors, but typically could range from 0.1 to 2.0 mm/yr.

In many intensively farmed regions, (top)soil is being removed by erosion much faster than it is being replaced by natural process. Removal of vegetation cover is enough to expose bare soil to rainsplash erosion at rates much greater than it is renewed. Once soil is bare, it becomes much more susceptible to erosion.

I think the additives you are referring to replenish the nutrient content of the soil, and not the the bulk material that would be produced by bedrock decomposition. With careful management, the fertility of existing soil can be maintained. But if the soil is allowed to be washed off or erode, for all practical purposes, the rate of replenishment is not fast enough for it to be classed as renewable in that sense.

This site has links to more aspects surrounding this issue.


What is the residue after plant matter is completely decomposed? What typical fraction of decomposing plant matter, left on the surface rather than buried, is not released in gaseous form?

My simple world view is that the plant structure has all come from the air, water content in the ground and a few nutrients and so I am wondering if the process of decomposition leaves just a tiny percentage of nutrients or if some larger fraction is left as solid material.

I had thought of posting this on sustainability.stackexchange though I am looking for a rational explanation rather than a practical experience.

Lastly, I appreciate the answer is likely to vary according to type of plant matter. If it helps I'm thinking of the UK, and a mixture of deciduous (beech, hazel, and oak), yew, spruce, and other grasses and shrubs.

Clearly I understand that the timescales applicable to woody stems and branches will be much longer than for green shoots and leaves.

From Mary, et al., 1996, Figure 1 on the second page shows a nice breakdown of there the Carbon and Nitrogen go when a plant decomposes. Hadas, et al., 2002 has experimental data from plants with C:N ratios from 11:1 to 136:1.

In summary, most carbon ends up in microbial biomass or as CO$_2$. If the process is allowed to proceed to infinity, then presumably, the microbial biomass will itself be decomposed by other microbes until all of it in the form of CO$_2$.

The nitrogen is mineralized, first into NH$_4^+$, then NO$_2^-$ and eventually all into NO$_3^-$ by various decomposing microbes. Normally these ions are attached to something else that they got from the soil and thus enter the soil. In the regular nitrogen cycle, the ions that eventually end up as NO$_3^-$ will be processed by other bacteria into atmospheric nitrogen (N$_2$). So, if decomposition proceeds to infinity, all the nitrogen would be expected to return to the atmosphere eventually too.

That leaves us with the small amounts of other biologically common elements such as phosoprous, calcium, etc. This will be the only stuff left. From Latshaw, 1934 (side note, not the oldest paper reference I've seen on Stack Exchange, but close!), and the chemical composition of a corn plant, considering all parts of the plant together, there is on average 44.9% oxygen, 44.0% carbon, 6.3% hydrogen, and 1.5% nitrogen by mass; all of these would be expected to leave as as gasses.

Of the remainder, representing 3.3% of the mass, probably most of that would stay. Whatever elements are left are most likely to form molecules with oxygen, since it is freely available in the air and likes to react with just about anything. Silicon, potassium and calcium don't seem to have any likely gaseous forms they could take, while sulfur (SO$_2$) and phosphorous (possibly P$_2$H$_4$) might take some more volatile forms. In the end, little will be left of the former plant, just a scattered residue of oxidized minerals, around 3% of the original mass.


If the nitrogen and oxygen in our atmosphere were doubled would the pressure double? As to P=ρgh, would the height of the atmosphere be affected by an increase in nitrogen and oxygen mass or would the height remain constant?  Thanks!

The surface pressure is just the weight of the atmosphere per unit area, so yes.

The density decreases with altitude so there is no well defined "top" to it. Assuming constant temperature (Isothermal-barotropic approximation) the density decreases exponentially with altitude.

If it were doubled there would the same portion of mass above any given altitude (but more mass above any given altitude).


Where can I find information about the basic concepts of sedimentary basins? There are a lot of papers on the web but they don't explain the concepts, they just mention them, taking for granted that the reader knows the concepts.
I mean piggyback basin, forearc, back arc, intracratonic, intramontane, etc.

In general, a good answer to "where can I learn the basic concepts of X" is "a textbook on X". For sedimentary concepts, you might try Nichols (2009), for instance. Academic papers are a publication vehicle for new research, so you'll seldom find much introductory material in them.

For terms like "intracratonic" and "intramontane", you might also find it useful to learn some common Greek and Latin prefixes and suffixes. If you look for "intra" in a list like this one, you'll find that it's Latin for "within", and you might be able to guess that "intracratonic" refers to something occurring within a craton.

If you just want to look up terms as you go, and you're happy with brief definitions, a specialist dictionary might also be helpful. For Earth Sciences, Allaby (2008) is a good concise dictionary, though it might be a little too concise if you're a beginner.

References

Allaby, M. ed., 2008. A Dictionary of Earth Sciences 3rd ed., Oxford: Oxford University Press.

Nichols, G., 2009. Sedimentology and Stratigraphy 2nd ed., Chichester: Wiley-Blackwell.


Measuring the circumference of the earth - revisited I have done a bit of research on this topic already and the easiest way seems to be the experiment by Eratosthenes. We pick two locations on the same latitude (of which we know the distance) and then measure the length of the shadow of a vertical stick at solar noon to get two angles. We can then figure out the difference between these angles and plug it into the formula:
\begin{align}
\frac{\text{angle}}{360°}&=\frac{\text{distance}}{\text{circumference of the earth}}\\[3mm]
\text{circumference of the earth}&=\frac{360°}{\text{angle}}\times\text{distance}\\
\end{align}
Now I would like to do a similar experiment. My family has friends who live 1260km west (and a little south) from us. Is there a way for us take a measurement at the same time and calculate the circumference of the earth? Obviously the formula above does no longer apply since we never have the same solar noon.

You can use the fact that the Earth's rotation period is known.  Then divide that period (use the solar day of 24 hrs 00 minutes instead of the sidereal day of 23 hrs 56 minutes) by the actual amount of time between your two solar noons and multiply the resulting factor by your 1260 km distance.
The result is the circumference ... of your latitude circle.  To get the circumference of a great circle and thus the Earth, you need to divide the calculated number above by the cosine of your latitude.  To get the latitude perform your experiment on an equinox and measure the shadow angle at solar noon.
Have fun, good luck!


What is the ratio of infra-red light absorbed by green house gases? I know that some gases like CO2, N2O and CH4 absorb infra red radiation.

What is the proportion or percentage of radiation absorbed by CO2 among all the gases?

There is no simple relationship since it all depends on the frequency (IR spectral lines for most species of molecules are a mess). The most direct and precise way of calculation is through line-by-line calculation from a large spectrum database. The atmospheric column will be very different based on angle off normal, weather, and even time of day (water content has diurnal variability, mostly).

Surface temperature and surface properties also influence the distribution of emitted IR.

See also: Atmospheric radiative transfer codes


How can I estimate a 2 m temperature from / in an atmospheric model? Numerical models of the atmosphere usually have their first atmospheric grid level well above 2 m, but the temperature at 2 m above ground level is something one often wants to calculate with such a model.

These models have some surface scheme to calculate temperatures at / in the ground and solve (approximated) Navier–Stokes equations on the atmospheric grid. Heat fluxes between these model components are usually parameterized with the help of Monin–Obukhov similarity theory. Hence, a diagnostic calculation of the 2 m temperature is needed.

What needs to be done to get a reasonable 2 m temperature? Is a simple use of a diagnostic formula using surface layer similarity again enough? What could be done based on data, assuming many simulations and observations are available?

Your premise is incorrect.
Numerical models normally have:

A full temperature profile
A specific field for the 2 metre temperature
A specific field for the skin temperature

For example, see ERA-40 daily fields, which both 2 metre temperature and Skin temperature, or CFS reanalysis 6-hour fields, which has Air temperature, Skin temperature, and Surface air temperature, (I think surface air temperature means 2-metre temperature, but check their full documentation to be sure).
It is not accurate to take the lowest temperature level in the temperature profile for either of the two, nor to interchange skin temperature with 2-m temperature.  But, in some cases, the data distribution may be such that either or both of these are actually attached to the temperature profile.  For example, the CFS hourly timeseries has the question:

Where is Sea Surface Temperature (SST) in CFSR? Where is Skin Temperature?

CFSR does not label SST and skin temperature grids differently than temperature grids on other levels. Select the parameter 'Temperature' and the level 'Ground or water surface' to obtain the SST/skin temperature grids, and then use the land/sea mask to determine whether a gridpoint is over water (SST) or land (skin temperature).

(I had the opposite problem, needing skin temperature, and being tempted to use 2 metre temperature instead, until I realised where the data were).
If you encounter a model that really only has the full temperature profile, then I would contact the authors to inquire.  Maybe it is a model that really only does well in the free atmosphere, and is not suitable for the extraction of (near-) surface temperatures.  The boundary layer can be a hard thing to model!


How Good is The Evidence For Snowball Earth? Some geologists say there were times between 770 million years BP and 630 million years BP when ice ages were so profound that the Arctic and Antarctic ice caps met at the equator. This is called the Snowball Earth theory.

Although at the beginning of this period, there were, so far as we know, no advanced invertebrates able to leave easily identifiable fossils, there were by the end of it, so how were they able to thrive and evolve under the ice? There must also have been early marine plants under the ice (there were none on land), so how did they survive?

The main evidence for this glaciation is apparent glacial markings on rocks in S.Africa and Australia, Couldn't there be other explanations for these apparent glacier tracks, apart from Snowball Earth? For example, Australia may have been closer to the S.Pole then, and some of the locations where evidence of glaciers was found might have been much higher above sea level than they are today.

Paul Hoffman's argument for Snowball Earth

So, first off, I'm just a guy with access to JSTOR and an interest in geology, so perhaps I'm not really qualified to assess "how good" the evidence is. But, I can read through the papers and summarize some stuff for you, which perhaps is sufficient to answer the question.

So, as suggested in the title, serious consideration of the Snowball Earth theory started with a Paul Hoffman paper in 1998, free copy linked here. The evidence in the initial paper is thus:

Inorganic $\delta^{13}$C showed decreases during glacial periods between 750 and 550 Ma that were 'enormous in comparison' with variation seen at other times in the Earth history. This references previous stratigraphic work by Alan Kaufman, a co-author on the paper we are discussing.
Based on a theory by Kirschvink (the geologist who proposed the Snowball Earth theory), an ocean completely sealed by sea ice would quickly become anoxic, leading to chemical reactions that would cause the observed changes in carbon deposition.
New stratigraphic work in the Otavi Group formation in Namibia confirms the drop in inorganic carbon, as well as providing evidence of glaciation on land at a latitude of ~12 S (latitude determined by paleomagnetic data; age determined by radiometry).
The geological evidence suggests that the proportion of organic carbon in total carbon burial drops to "virtually zero" immediately after the glaciation begins.
The paper then presents evidence that a large volcanic event with C)$_2$ levels > 300 times the present could "undo" the Snowball Earth event.

In the conclusion, the authors say that a Snowball Earth explains the evidence from carbon isotope excursions, but no alternative hypothesis does. This is discussed more in detail in Hoffman, et al., 1998a (an article by the same authors, the same year) and Hoffman and Schrag, 2002. Among hypotheses rejected include a period of ocean stagnation and overturn; the Earth having a larger axial title until the end of the Proterozoic, true polar wander, a major bolide impact, deep ocean anoxia and others.

The point I want to make here is that the questions that you ask in the OP don't fit into the original explanation for why there might have been a Snowball Earth episode. It is true, that without accurate fossil dating, radiometric methods can't prove that near-equatorial glaciers occured in multiple places at the same time. But, that isn't really a required proof. Evidence for Snowball Earth is "good" as long as it is the most likely explanation for the observed paleomagnetic, stratigraphic, and carbon isotope data.

That last is the part that I am perhaps not qualified to speak on; you'd have to do a full literature review on both Snowball Earth and alternate theories to determine which has the best evidence supporting it. But, clearly there are many geologists who thing that Snowball Earth is the "best" hypothesis.

Answers to specific questions

Although at the beginning of this period, there were, so far as we know, no advanced invertebrates able to leave easily identifiable fossils, there were by the end of it, so how were they able to thrive and evolve under the ice?

From Kirshvink, et al., 2000,

  Finally, we speculate that the predicted severity of climate and
  geochemical change during the snowball event and its aftermath may
  have forced enormous biological adaptation and left recognizable
  signatures in the phylogenies of extant organisms and their genes.

The extreme geochemical conditions include significant changes oxygen and iron availability. Thought the above article specifically addresses an earlier Snowball Earth episode, the suggestion is that the few organisms that did survive the glaciation had novel geochemical adaptations that allowed them to explode into the much more friendly world environment that existed after glaciation.

Indeed, the Ediacara fauna appeared after the glaciations had passed; from Hofmann, et al., 1990 (not the same Hoffman/Hofmann; also couldn't find a free full copy):

  The Ediacara fauna generally regarded as containing the oldest
  metazoan fossils, has been described from about 25 localities around
  the world; all occurances to date place it above the highest
  Proterozoic tillites of the Varanger glacial epoch.

The Varanger glacial epoch is what is now theorized to be the Cryogenian period, divided into two glaciations, the Sturtian and Marinoan.

So, overall, the explosion of evolution and diversity happened after the glaciation passed, and it happened because radial new biochemical processes had to be evolved to survive in the radically divergent marine chemistry of the frozen ocean.

There must also have been early marine plants under the ice (there were none on land), so how did they survive?

Eukaryotic algae (like red and brown algae) existed before the Cryogenian, and survived until after. There are many mechanisms for them to have survived. Firstly, algae do live on the snow on the terrestrial surface of Antarctica; such "snow algae" could have survived on Snowball Earth.

Secondly, there is no consensus that the surface of the Ocean was uniformly thick. Some modeling, for example from Pollard and Kasting, 2005 indicates that the sea ice was on the order of meters thick in the equatorial regions. In that case, algae could have easily survived on the underside of ice sheets, as it does in the modern arctic and antarctic. A thin, cracking, and periodically melting (under tropical solar radiation) state would be consistent with conditions in the polar regions today, and is quite capable of supporting life.

Couldn't there be other explanations for these apparent glacier tracks, apart from Snowball Earth? For example, Australia may have been closer to the S.Pole then, and some of the locations where evidence of glaciers was found might have been much higher above sea level than they are today.

I haven't done a deep dive, but the latitude of various points of the Earth's surface can be estimated by paleomagnetic data. Note that the many of the alternate explanations (such as increased axial tilt and true polar wander) also include mechanisms for explaining why the magnetic record is wrong (i.e. the magnetic poles were not where we though they were).

However, this is something of an Occam's Razor situation. In order to explain tropical glaciers without Snowball Earth, you have to explain how the Earth was physically rotating on a different axis. While possible, it takes a lot of energy to make the Earth move from one axis of rotation to another. Snowball Earth is a simpler explanation from the energy physics point of view.

As mentioned earlier, there are two links to papers where Hoffman and company dismiss various alternate explanations.


Why can't we dig deeper? I recently read on another SE site that there's a limitation on how deep we can dig into the earth.

A Google search reveals that temperature is the problem.

I quote from a Popular Mechanics article which speaks on the Kola Superdeep Borehole

  The limiting factor is almost always the temperature. The Kola was abandoned in 1992 when workers hit 356 degrees Fahrenheit, far hotter than they had anticipated. The tunnel was eventually closed off in the early 2000's.

356$^\circ$F is 180$^\circ$C, for those of you who don't get Fahrenheit, like me.

Iron's melting point is well above 1000$^\circ$C, and I think it is okay to assume most of our machines have iron as a major constituent. Alloys with iron will only have higher melting points.

Why is 180$^\circ$C a problem? Why can't we dig deeper?

Here is a thermal profile of the borehole:

(Source: Fig 5 in Yuri A. Popov, Sergei L. Pevzner, Vyacheslav P. Pimenov, Raisa A. Romushkevich,
New geothermal data from the Kola superdeep well SG-3,
Tectonophysics,
Volume 306, Issues 3–4,
1999,
Pages 345-366,
ISSN 0040-1951,
https://doi.org/10.1016/S0040-1951(99)00065-7.)

This borehole is (almost) vertical and not an angle, so its depth is true (11662 m) and it is quite warm down there, around 180 degrees Celsius as shown in the above figure. I assume temperatures were similar in other shafts drilled at maximum depth at 12262 m.

The equipment they used initially for the 1982 borehole down to 11662 m was made to be able to work in thermal stability up to 200 degrees Celsius (Source: Kozlovsky, Yevgeny A., and N. I. Adrianov, eds. The superdeep well of the Kola Peninsula. Springer Berlin Heidelberg, 1987.) Consequently I assume the equipment used for the later shaft that reached 12262 m was of similar or better make than the original.

The problem is not the temperature against the barrel only: there is heat due to the shear (rotation) and let's not forget the weight of the shaft down the base. This is why the thermal stability of the system is to be considered in addition to the resistance of single parts of the drill system. So while hotter than they expected, it was within the operating range conform to the specifications of the make - but yet very near the thresholds and thus problematic.

The problem lied also with the rock being more and more plastic deep down in the borehole, due to pressure, porosity and water, making it a very difficult challenge to keep the borehole open each time the shaft need to be replaced or removed, adding difficulties to this already never-been-done-before project.

So this sum of challenges are probable reason why the project was interrupted before reaching the initial goal of 15 km.


Why do we measure eustatic sea-level from the center of earth? Earth is rotating so it has a ellipsoidal shape. The measurement will therefore be different from equator and pole. So why do we measure eustatic sea-level from the center of earth?

The centre of the Earth is the only true unchanging datum.

Land masses rise and fall due to geological actions such as melting of land based ice sheets, volcanism, plate tectonics, erosion, sedimentation and ground stresses causing land masses to move relative to one another at faults.

As stated here, sea level changes resulting from,

  Eustatic change (as opposed to local change) results in an alteration to the global sea levels due to changes in either the volume of water in the world oceans or net changes in the volume of the ocean basins.

With the elevation of land altering over time (rising or falling depending on location), the true change in sea levels cannot be determined from using points on the Earth's surface as a datum; particularly when the volume of the ocean basins changes due to land mass movements.

True changes in sea levels can only be ascertained from an unchanging datum, which on Earth is the centre of the Earth.


Difficulty interpolating near poles using lat/lons I've been writing a 2D interpolation scheme for use on the globe which utilizes lat/lon values.  Once I try to use values closer to the poles, latitude distortion becomes an issue.  For example:
270,-86 ---------- 0, -90          This looks like an ordinary square on the globe
        |        |                  but when these values are projected to a plane,
        |        |                  they create a shape that's unworkable.
        |        |                  Note that opposite corners have the same latitude.
225,-84 ---------- 180,-86

I've been converting from spherical to cartesian coordinates in an attempt to create a 2D plane but there's still the issue of these planes existing in three dimensions and I've had difficulty "flattening" them.  Surely there must be a common method for dealing with the latitude distortion near the poles but I don't know what it is.  Any help would be much appreciated.
Thanks.

$\color{blue}{\text{The answer here presumes that Earth is a sphere.}}$
$\color{blue}{\text{This is not fully true, but the question seems to build in that assumption.}}$
$\color{blue}{\text{That should be clarified to determine if this answer is relevant.}}$
Do not use a 2D-plane which does not generally exist for four points.  Use a tetrahedron.  You can interpolate inside the tetrahedron and then project the interpolated point (which will be inside the globe) radially onto the globe's surface.
Say you pick the South Pole, S, and three points A, B, C at 60° south latitude and longitude 0°, 90° east, 90° west.  Converting these coordinates to Cartesian form with the South Pole at $(0,0,-1)$ prime meridian passing through $(1,0,0)$, we get the coordinates
South Pole = $(0,0,-1)$
A = $(1/2,0,-\sqrt3/2)$
B = $(0,1/2,-\sqrt3/2)$
C = $(0,-1/2,-\sqrt3/2)$
Now suppose you want to interpolate with a weight of 1/2 for S and 1/6 for each of the other three points.  Take the linear combinations of the above coordinates with those coefficients to get a point P inside the tetrahedron:
$P=(1/2)(0,0,-1)+(1/6)(1/2,0,-\sqrt3/2)+(1/6)(0,1/2,-\sqrt3/2)+(1/6)(0,-1/2,-\sqrt3/2)=(1/12,0,-(2+\sqrt3)/4)$
Point P has the following physical significance:  if you draw the smaller tetrahedron PABC, opposite S, then this tetrahedron has 1/2 the volume of the big tetrahedron ABCS, where 1/2 is the coefficient you put in for S.  For this choice of P the corresponding tetrahedra opposite A,B,C will each have 1/6 the volume of the big one.
Now we need to project this point onto the surface ofthe globe.  Work out its distance $d$ to the origin:
$d^2=(1/12)^2+0^2+((2+\sqrt3)/4)^2=(16+9\sqrt3)/36\approx 0.8775, d\approx 0.9367$
Note that $d<1$. Divide this $d$ into the coordinates of P getting the approximate result
$P'\approx (0.0890, 0, -0.9960)$
Converting back to spherical coordinates then gives a latitude of $\approx 84.90°=84°54'$ south and longitude zero, the latter due to equally weighting the eastern and western hemispheres in this example.  The interpolated point is more than halfway from the 60° south latitude circle to the South Pole because we interpolated from a distribution of points along this circle rather than a single point; the centroid of of this distribution ( $\triangle ABC$) is at more than 60° south latitide.