earth_science/query.jsonl

{"query":"We know (think?) that Earth has three Hadley cells per hemisphere, but from observing gas giants such as Jupiter, we see that they have many more cells. According to a link from a comment in this question, Titan might have one cell going from north to south poles.\n\nWhat factors affect the number of cells a planet has, and how? Or to put it another way, given a hypothetical planet with atmosphere, what facts would you need to know in order to guess at how many cells it has?","reasoning":"this post want to find out the factor determines the number of Hadley cells. The anwser use some formula to infer the number is determined by the planet's rotation rate and the latitudinal distribution of heating from the parent star.","id":"0","excluded_ids":["N\/A"],"gold_ids_long":["number_of_hadley_cell\/Hadley_cell.txt"],"gold_ids":["number_of_hadley_cell\/Hadley_cell2.txt","number_of_hadley_cell\/Hadley_cell3.txt"],"gold_answer":"$\\begingroup$\n\nWell for one, this will surely be the speed of planetary rotation and the wind\nspeeds your atmosphere can generate in North-South-direction.  \nIn my understanding those cells form as N-S winds flow and become deflected\nfrom this direction. So the number of cells will be determined by the winds\nthat start either at the equator or the pole and the distance that they can\ncover before being deflected into completely zonal direction.\n\nTo have a rough idea about this distance I tried to estimate this (in a very\nquick, dirty and most likely extremely wrong way) by assuming the simplified\nNavier-Stokes equation in planetary coordinates on synoptic scales:  \n$$\\partial_t \\vec v = 2 \\Omega \\sin\\Theta (\\vec v \\times \\vec z),$$  \nwhere  $\\Theta$  is the planetary latitude,  $\\Omega=\\Omega(\\Theta)$  the\nlocal planetary rotation frequency at the given latitude and  $v_0$  the local\nwind speed, leading to a harmonic equation for the meridional speed  \n$$\\partial_{tt} v_{\\phi} = -(2\\Omega \\sin\\Theta)^2 v_{\\phi},$$  which with the\nusual arguments of scale-analysis gives us a timescale  $\\tau_{\\phi}$  for the\nperiodic movement involved in solutions of that equation, of  \n$$\\tau_{\\phi} \\sim \\frac{1}{2\\Omega \\sin\\Theta}$$  \ncorresponding to a distance  $$ d \\sim \\frac{v_0}{2\\Omega \\sin\\Theta_0}$$\ncovered by the vortex. Of course, I cheated here by assuming the initial speed\n$v_0 = \\text{const}$  and the initial Coriolis-factor constant with  $\\Theta =\n\\Theta_0$  .  \nAs now such a \"structure\" (solution of the above eqs.) will have a size of\n$2d$  in the meridional direction, having space of  $\\pi R_{\\text{planet}}$\nour number of Hadley cells per hemisphere becomes simply  $$N = \\frac{\\pi\nR_{\\text{planet}} \\Omega \\sin\\Theta_0}{v_0}$$  \nWhere we'd need to estimate this number starting at the poles, as the\nCoriolis-parameter vanishes at the equator.\n\nI will later (if I don't forget it) pluck in some numbers and see how bad this\nestimate is, or perhaps someone can try that. Anyway, I'm open for\nimprovements of those arguments from anyone who knows something, but a quick\nlook into Holton, _An Introduction to Dynamic Meteorology_ , unfortunately\ndidn't reveal much.\n\nBut to also address your question a little bit further: Of course, we'd need\nto have some climatic model to be able to estimate  $v_0$  and know the speed\nof planetary rotation. Independent of how bad my formula is, the initial\narguments of deflection vs. 'climbing the meridian' should hold for the\nformation of a Hadley cell.  \nReturning winds from higher atmospheric layers, surface friction in the\natmospheric boundary layer will also play a role for an exact calculation.\n\n* * *\n\nAddendum: [ Rhines (1975)\n](http:\/\/journals.cambridge.org\/action\/displayAbstract?fromPage=online&aid=373502&fileId=S0022112075001504)\nhas however found a relation  $N \\sim R_{planet} \\sqrt{\\frac{\\Omega}{v_0}}$  ,\nby considering how turbulent eddies will break up energy-limited by zonal\njets. Also turbulent eddies can provide a good mechanism for justifying a\nlocally constant  $v_0$  , that I simply assumed in my calculation above.\n\nOn the other hand I just noticed a trivial error in my above calculation and\ncleared that. The fraction that is N was the other way round. Sorry for that.\n\n* * *\n\nI wanted to note one other thing that seems important to me (and is perhaps\nalso to anyone on this planet..):  \nWhile this rule of thumb-calculations can work out, there is more physics that\nplay a role in shaping the exact morphology of circulation-cells on a planet.\nNamely the radiative equilibrium in the atmosphere, which links the exact\npositions of those cells to a changing climate.\n\nAs a [ study\n](http:\/\/www.nature.com\/ngeo\/journal\/v1\/n1\/full\/ngeo.2007.38.html) suggests by\nmeasuring Tropical to Polar-Jet distances and Tropopause heights, those cells\ncan expand and reshape the environment people live in."}
{"query":"We see tropical cyclones (going by different names e.g. hurricane, typhoon, cyclone) all over the tropics, but it seems that there are never any storms in the southern Atlantic. See this map of tropical cyclone activity and note the lack of activity in the south Atlantic and also in the south Pacific until you near Australia.\r\n\r\nWhere are all the tropical cyclones in the southern Atlantic basin?","reasoning":"The post asked about why there's no hurricanes in the southern Atlantic basin. The reason anwser gave is that it's about naming conventions based on location","id":"1","excluded_ids":["N\/A"],"gold_ids_long":["hurricanes_in_the_southern_Atlantic_basin\/Tropical_cyclone.txt"],"gold_ids":["hurricanes_in_the_southern_Atlantic_basin\/Tropical_cyclone1.txt"],"gold_answer":"$\\begingroup$\n\nThere have been tropical storms and hurricanes in the south Atlantic, with,\naccording to NOAA's webpage [ Subject: G6) Why doesn't the South Atlantic\nOcean experience tropical cyclones?\n](http:\/\/www.aoml.noaa.gov\/hrd\/tcfaq\/G6.html) , with a hurricane forming in\nthe south Atlantic making landfall in Brazil in 2004 and a strong tropical\ndepression\/weak tropical storm that formed off the coast of Congo in 1991 -\nbut these are exceedingly rare.\n\nThe reason why these storms generally don't occur in the south Atlantic,\naccording to the Penn State webpage [ Upper-level Lows\n](https:\/\/courseware.e-education.psu.edu\/public\/meteo\/upperlevel_lows.html) as\nbeing:\n\n> There are two primary reasons why tropical cyclones are rare in the south\n> Atlantic basin. First, vertical wind shear between 850 mb and 200 mb is\n> typically greater than 10 meters per second (check out the long-term average\n> of vertical wind shear between 850 mb and 200 mb). To make matters worse,\n> westerly shear dominates over latitudes where tropical cyclones would be\n> most likely to form. Second, easterly waves from Africa do not form south of\n> the equator (the MLAEJ is a northern hemispheric singularity.\n\nFurther, from the NASA News page [ The Nameless Hurricane\n](http:\/\/science.nasa.gov\/science-news\/science-at-nasa\/2004\/02apr_hurricane\/)\n, they provide an extension to the explanation with\n\n> Vertical wind shears in the south Atlantic are too strong for hurricanes,\"\n> Hood explains. Winds in the upper troposphere (about 10 km high) are 20+ mph\n> faster than winds at the ocean surface. This difference, or shear, rips\n> storms apart before they intensify too much\n\nAn article [ The first South Atlantic hurricane: Unprecedented blocking, low\nshear and climate change\n](http:\/\/onlinelibrary.wiley.com\/doi\/10.1029\/2005GL023390\/full) (Pezza and\nSimmonds, 2005) suggest that the implications of the southern hemisphere\nhurricane presents\n\n> evidence to suggest that Catarina could be linked to climate change in the\n> SH circulation, and other possible future South Atlantic hurricanes could be\n> more likely to occur under global warming conditions.\n\n_Catarina refers to the southern hemisphere hurricane_\n\n_SH = Southern Hemisphere_\n\nedited to add an [ NASA Earth Observatory\n](http:\/\/earthobservatory.nasa.gov\/NaturalHazards\/view.php?id=12935) satellite\nimage of the hurricane:\n\n![enter image description here](https:\/\/i.sstatic.net\/Z3EMC.jpg)"}
{"query":"How long does it take the magnetic field to move once the poles start to flip? What environmentally would change? Does the core of the Earth flip?\n\nThe magnetic poles are moving now. When will it start to move faster and how would a compass behave?","reasoning":"The post wants to know what happens when the North and South poles filp. The anwser indicates that pole reversal will ease the magnetic field. The Earth's magnetic field temporarily weakens, allowing more cosmic radiation and solar wind to reach the Earth.There may be some low-level radiation effects on living organisms, but likely not enough to cause a mass extinction event.Apart from increased radiation, there is limited direct impact on human activities.After the reversal is complete, the Earth's magnetic field will re-establish itself, but with the magnetic north and south poles switched.","id":"2","excluded_ids":["N\/A"],"gold_ids_long":["pole_flip\/Geomagnetic_reversal.txt"],"gold_ids":["pole_flip\/Geomagnetic_reversal5.txt","pole_flip\/Geomagnetic_reversal1.txt","pole_flip\/Geomagnetic_reversal6.txt","pole_flip\/Geomagnetic_reversal4.txt","pole_flip\/Geomagnetic_reversal3.txt","pole_flip\/Geomagnetic_reversal2.txt"],"gold_answer":"$\\begingroup$\n\nFirst of all I will try to explain what a geomagnetic pole reversal is.\n\nA magnetic pole reversal happens when the magnetic field weakens until it can\nno longer sustain itself. This can take 1000-3000 Years or more to complete\nthe time it takes is very variable.\n\nAfter years with a weak and sometimes variable magnetic field. The magnetic\nfield re emerges in its original, or in a changed direction. So it is not the\npoles moving over the surface of earth.\n\nLink [ https:\/\/en.wikipedia.org\/wiki\/Geomagnetic_reversal\n](https:\/\/en.wikipedia.org\/wiki\/Geomagnetic_reversal)\n\nWhat happens during a geomagnetic pole reversal.\n\nDuring a pole reversal earths magnetic field is weak so our planet is less\nprotected from cosmic radiation and from the solar wind.\n\nLink [ https:\/\/en.wikipedia.org\/wiki\/Earth%27s_magnetic_field\n](https:\/\/en.wikipedia.org\/wiki\/Earth%27s_magnetic_field)\n\nThis increase in cosmic radiation does not fit any of the known extinction\nevents that have happened in Earth's history. This does not mean nothing at\nall will happen to life during this time it only means the dangers are low.\n\nIf you want to follow how the cosmic radiation changes you can do this on the\nlast part of this page [ http:\/\/spaceweather.com\/ ](http:\/\/spaceweather.com\/)\n\nLink [ https:\/\/en.wikipedia.org\/wiki\/Cosmic_ray\n](https:\/\/en.wikipedia.org\/wiki\/Cosmic_ray)\n\nI mentioned in my comment Earth's magnetic north pole is really in the south.\nTo understand how this can be true in a magnetic compass the magnetic north\npole is repelled by Earth's north pole so it does point in the opposite\ndirection (a bad explanation but it is how it works)."}
{"query":"I have never understood why earth's inner core is solid. Considering that the inner core is made of an iron-nickel alloy (melting point around 1350 C to 1600 C) and the temperature of the inner core is approximately 5430 C (about the temperature of the surface of the sun). Since Earth's core is nearly 3-4 times the melting point of iron-nickel alloys how can it possibly be solid?","reasoning":"This post tries to find out why the inner core of earth is solid. According to the temperature and pressure in the core, ","id":"3","excluded_ids":["N\/A"],"gold_ids_long":["solid_inner_core\/Phase_diagram.txt","solid_inner_core\/Earth%27s_inner_core.txt"],"gold_ids":["solid_inner_core\/Earth%27s_inner_core1.txt","solid_inner_core\/Phase_diagram3.txt"],"gold_answer":"$\\begingroup$\n\nEarth's inner core is solid even though the temperature is so high because the\npressure is also very high. According to [ the Wikipedia article\n](http:\/\/en.wikipedia.org\/wiki\/Inner_core) on the Earth's inner core, the\ntemperature at the center is $5,700\\ \\text{K}$ and the pressure is estimated\nto be $330$ to $360\\ \\text{GPa}$ ($\\sim3\\cdot10^{6}\\ \\text{atm}$).\n\nThe phase diagram shown below (taken from [ this paper\n](http:\/\/www.agu.org\/books\/gd\/v031\/GD031p0083\/GD031p0083.pdf) ) shows the\nliquid\/solid transition, where fcc and hcp are two different crystalline forms\nof solid iron. You can see clearly from the slope of the line going off toward\nthe upper right that iron should be solid at this temperature and pressure.\n\n![enter image description here](https:\/\/i.sstatic.net\/w82eb.png)"}
{"query":"The enlightening image below is of a lightning strike slowed down at 10,000 frames per second. It can be seen that the most intense flash produced from the lightening occurs in the direction from the ground up. Why does this final \"ground-up\" strike occur and why is it so much brighter and faster than the initial part of strike heading towards the ground?","reasoning":"The post wants to know why the most powerful lightening strike comes from the ground-up. The reason is the existence of the opposite chargers.","id":"4","excluded_ids":["N\/A"],"gold_ids_long":["ground_up_lightening\/Lightning.txt"],"gold_ids":["ground_up_lightening\/Lightning6.txt"],"gold_answer":"$\\begingroup$\n\n> **Does lightning strike from the sky down, or the ground up?**\n>\n> The answer is both. Cloud-to-ground lightning comes from the sky down, but\n> the part you see comes from the ground up. A typical cloud-to-ground flash\n> lowers a path of negative electricity (that we cannot see) towards the\n> ground in a series of spurts. Objects on the ground generally have a\n> positive charge. Since opposites attract, an upward streamer is sent out\n> from the object about to be struck. When these two paths meet, a return\n> stroke zips back up to the sky. It is the return stroke that produces the\n> visible flash, but it all happens so fast - in about one-millionth of a\n> second - so the human eye doesn't see the actual formation of the stroke.\n>\n> **Source:** [ National Severe Storms Laboratory\n> ](https:\/\/www.nssl.noaa.gov\/education\/svrwx101\/lightning\/faq\/)\n\nThe reason is that when cloud-to-ground strike approaches the ground, the\npresence of opposite charges on the ground enhances the strength of the\nelectric field and the \"downward leader\" strike creates bridge for the \"return\nstroke\"; this [ per the wiki page for Lightning\n](http:\/\/en.wikipedia.org\/wiki\/Lightning#Upward_streamers) .\n\n* * *\n\n**Cloud to cloud and Intra-Cloud Lightning**\n\n![enter image description here](https:\/\/i.sstatic.net\/vBIiD.jpg)\n\nMight be worth also noting that cloud-to-ground is not as common as **[ Cloud\nto cloud (CC) and Intra-Cloud (IC\n](http:\/\/en.wikipedia.org\/wiki\/Lightning#Cloud_to_cloud_.28CC.29_and_Intra-\nCloud_.28IC.29) ) ** :\n\n> Lightning discharges may occur between areas of cloud without contacting the\n> ground. When it occurs between two separate clouds it is known as inter-\n> cloud lightning, and when it occurs between areas of differing electric\n> potential within a single cloud it is known as intra-cloud lightning. Intra-\n> cloud lightning is the most frequently occurring type.\n\n**Ground-to-Cloud**\n\n![enter image description here](https:\/\/i.sstatic.net\/RM2Xe.jpg)\n\nAppears that ground-to-cloud is possible, though normally only a result of a\nman-made object creating \"unnatural\" electric potential, and is the least\ncommon type of lightning."}
{"query":"As far as I understand it is perfectly valid for air to have 100% humidity. At that point, all water can still exist in form of vapor, non-condensed.Does it immediately start to rain if humidity is >100%?If so, why do we have slight rain and heavy rain if any 0.1% above 100% drops out immediately? That should always be only a small amount of rain and rainstorms could not be explained.If not, what is the limit of humidity if not 100% and why can it exceed 100%?","reasoning":"The post wants to know the relationship between whether it rains or not and humidity. But humidity alone is not a sufficient condition for rain to start. High humidity means there is a lot of water vapor in the air, but rain requires several other factors:","id":"5","excluded_ids":["N\/A"],"gold_ids_long":["humidity_and_rain\/Convective_available_potential_energy.txt","humidity_and_rain\/Kelvin_equation.txt"],"gold_ids":["humidity_and_rain\/Kelvin_equation1.txt","humidity_and_rain\/Convective_available_potential_energy1.txt","humidity_and_rain\/Kelvin_equation4.txt","humidity_and_rain\/Kelvin_equation5.txt","humidity_and_rain\/Convective_available_potential_energy3.txt","humidity_and_rain\/Kelvin_equation3.txt","humidity_and_rain\/Kelvin_equation2.txt"],"gold_answer":"$\\begingroup$\n\nShort answer: humidity is not a proxy for rain starting and no, it does not\nstart raining automatically when 100% humidity is reached (haze or clouds can\nform though). The onset of rain is dependent on many things including\nhumidity, but a specific value of humidity is not a sufficient condition for\nrain.\n\n* * *\n\nWater vapor is a gas and invisible. The amount of water vapor in the air can\nbe expressed as relative humidity (RH) which is the ratio of water vapor\npressure ($e$) and saturation water vapor pressure ($e_s$). Saturation vapor\npressure is the partial pressure of vapor when evaporation and condensation\nrates are equal, represented by RH=100%. When RH > 100% net condensation\noccurs, but water has its own ideas.\n\nIn a mixture of pure dry air and water vapor, water will not condense until\naround 400% RH. Reasons for this are a bit complicated but it has to do with\nvery small droplets being more likely to evaporate as their curvature is very\nlarge ( [ Kelvin effect ](https:\/\/en.wikipedia.org\/wiki\/Kelvin_equation) ,\nsaturation vapor pressure is higher over curved surfaces than flat ones).\nLuckily for us, our atmosphere is not pure air but has small particulates\nsuspended in it (aerosols). Some of these aerosols are classed as cloud\ncondensation nuclei (CCN) and enable droplet formation at lower relative\nhumidities. These work by forming a solute in water increasing the energy\nneeded to break bonds and evaporate the water ( [ Raoult's_law\n](https:\/\/en.wikipedia.org\/wiki\/Raoult%27s_law) )\n\nThe combined interaction of these are described by [ K\u00f6hler theory\n](https:\/\/en.wikipedia.org\/wiki\/K%C3%B6hler_theory) and describe droplet\ngrowth in terms of drop size, solute and supersaturation (RH-100%). In a\nnutshell, there is a critical drop size below which drop size decreases for\ndecreasing supersaturation and above which drop size _increases_ for\ndecreasing supersaturation. The critical supersaturation is the\nsupersaturation needed to attain the critical drop size, and is generally\nsmall (e.g. 0.3% supersaturation).\n\nDroplets below the critical size are 'haze drops' and these make up the haze\nyou see on very humid days. Drops that reach the critical size can continue to\ngrow to become cloud drops. The condensed water is carried in the air but is\nno longer water vapor and is not part of relative humidity (but does\ncontribute to the parcel density)\n\nSo... when does it rain?\n\nIt rains when water vapor is in the presence of CCN, driven to a\nsupersaturation causing growth to the critical drop size (on the order of\n$\\mu$m) and continuing to grow to cloud drops and further to the much bigger\ndrop sizes that make up drizzle (100-300 $\\mu$m)and rain drops(mm), a process\nthat takes around 40 minutes. Drops will grow until the updraft can no longer\nsupport their mass and then they fall from the cloud as rain.\n\nYour question asks at what humidity does it rain, but what surface humidity\ndetermines is how high the cloud bases are. When the dew point depression (the\ndifference between temperature and dew point) is high, the cloud bases will be\nhigher than when the dew point depression is small. As air rises it cools, and\nat some point 100% RH is attained. If there is forcing for vertical ascent,\nparcels can rise to this height and then to a height where they freely convect\ndue to decreased parcel density caused by the release of energy during\ncondensation (see: [ CAPE\n](https:\/\/en.wikipedia.org\/wiki\/Convective_available_potential_energy) ).\n\nSo far to have rain we've needed water vapor (but not at 100% at the surface),\naerosols to aid condensation (CCN) and a way to cool the air to reach 100% RH\nvia lifting. It is these three things -- moisture, aerosols and cooling, that\nwe need for a rain storm. We can have 100% RH days that are just hazy or foggy\nthat do not rain and we can have days with mextremely little RH (e.g. deserts)\nthat result in little rainstorms or large severe storms. We also have storms\nwe call 'elevated convection' that are completely disconnected from surface\nconditions and when these storms cause rain is not related to surface humidity\nat all.\n\nIf you are looking for a magic trigger for rain, your closest bet will be\nlooking at temperature, dew point and the height parcels need to attain to\nfreely convect ( [ LFC\n](https:\/\/en.wikipedia.org\/wiki\/Level_of_free_convection) ). If there is\nforcing for parcels to get that high and instability above, then rain is a\ngood bet. Forcing for lift can be anything from convergence along a boundary\n(sea breeze, cold front, outflow from another storm), orographic lifting\n(mountains, hills), thermally or dynamically forced.\n\n* * *\n\nTo address your specific concerns:\n\n> Water vapor is the gaseous state of water and is invisible\n>\n\n>> Invisible to me would mean that clouds are excluded from humidity.\n\nCorrect, clouds are not part of humidity, they are suspended liquid water\ndrops, usually condensed onto a solute of some kind.\n\n> Absolute humidity is the total mass of water vapor present in a given volume\n> of air.\n>\n\n>> That again makes me think a cloud must be included.\n\nWater vapor contributes to humidity but water vapor does not include liquid\nwater. Cloud water, ice, snow, rain, grapple, hail all contribute to the total\nmass of a volume of air, but are not humidity.\n\n> The humidity is affected by winds and by rainfall.\n>\n\n>> Rainfall certainly decreases humidity, but it is not stated at what\npercentage it starts to rain.\n\nHumidity will increase during a rainstorm as rain and puddles evaporate.\nTemperature will decrease toward the wet bulb temperature. As noted in the\nanswer, there isn't a magic number of %humidity that causes rain to start."}
{"query":"Forgive my ignorance of the subject but I was always wondered about the exact reason of this phenomenon.\n\nVernal equinox happens around March 20, whereas autumnal equinox happens around September 22, so wherever you are in Northern Hemisphere, the length of the day, and consequently the amount of solar energy that reaches the place should be almost the same.\n\nHowever the average temperatures differ widely, for example Toronto has average temperatures of 2\u00b0C to 6\u00b0C on March 20th, and 14\u00b0C to 19\u00b0C on September 22nd. So around 12\u00b0C difference [link].\n\nSo obviously there is some sort of temperature inertia, as temperatures seem to experience a delay in responding to changes in day length.\n\nWhat is the main reason for it? Is it effect of sea ice or snow-covered land albedo? Energy stored in oceans? Energy absorbed by melting snow and ice?","reasoning":"The post wants to know the reason behind the fact that the March is colder in the Nothern Hemisphere. The phenomenon is called season lag. Basically temperatures lag behind the peak in solar radiation by several weeks because it takes time for the land, atmosphere, and especially the oceans to absorb and release the accumulated heat energy due to their different thermal properties and capacities.","id":"6","excluded_ids":["N\/A"],"gold_ids_long":["colder_march\/Seasonal_lag.txt"],"gold_ids":["colder_march\/Seasonal_lag1.txt","colder_march\/Seasonal_lag2.txt","colder_march\/Seasonal_lag3.txt"],"gold_answer":"$\\begingroup$\n\n**The phenomenon is called[ seasonal lag\n](http:\/\/en.wikipedia.org\/wiki\/Seasonal_lag) . **\n\nThere's [ a more extensive answer elsewhere on this site\n](https:\/\/earthscience.stackexchange.com\/questions\/2490\/equinoxes-and-\nsolstices-start-of-the-season-or-mid-season\/2603#2603) but the basic idea is\nthat temperature lags behind insolation by several weeks, because it takes\ntime to change the mean temperatures of the land, the atmospehere, and\nespecially oceans change their mean temperature. This diagram tries to show\nthe lag, along with various ways of reckoning the seasons:\n\n![enter image description here](https:\/\/i.sstatic.net\/gWNb5.png)"}
{"query":"Intuitively, it makes perfect sense to think that the coldest day of the year would be the day that gets the least sunshine, the winter solstice. In the northern hemisphere, this occurs a few days before Christmas. But as anyone who lives in places that gets snow can tell you, the most bitter parts of winter are in January and February, not December.\r\n\r\nWhy does it get so much colder when sunlight (and the warmth it should be bringing with it) is increasing?","reasoning":"The post wants to know that why the weather gets colder after the solstice, i.e., the less sunlight day of the year. The reason behind it is the pheomenon of seasonal lag","id":"7","excluded_ids":["N\/A"],"gold_ids_long":["colder_winter_after_solstice\/Seasonal_lag.txt"],"gold_ids":["colder_winter_after_solstice\/Seasonal_lag2.txt","colder_winter_after_solstice\/Seasonal_lag1.txt"],"gold_answer":"$\\begingroup$\n\nPrimarily because of **inertia** . This phenomenon is called [ seasonal lag\n](https:\/\/en.wikipedia.org\/wiki\/Seasonal_lag) .\n\nIt is true that the December solstice is the moment that the northern\nhemisphere gets the lowest total amount of insolation. Conversely, the June\nsolstice corresponds to the moment of maximum insolation. The oceans, and to a\nlesser degree the land, absorb a lot of heat. Due to the large heat capacity\nof water and the large amounts of water, the seasonal lag can be considerable.\nIn general, mid-latitude areas near large bodies of water have the largest\nseasonal lag, to the extent that the warmest month of the year in most of\nwestern Europe is August.\n\nIt is illustrated very well by this _Warmest day of the Year_ map that NOAA\nNCDC (now NCEI) produced for the contiguous United States:\n\n[ ![NCDC\/NCEI map of warmest day of the year](https:\/\/i.sstatic.net\/b4A5P.jpg)\n](https:\/\/i.sstatic.net\/b4A5P.jpg)\n\nAs expected, areas with a humid climate, such as southern Texas and nearby\nareas, tend to have the warmest day of the year in August. The west coast is\neven more extreme, with some places having the warmest day in September.\nConversely, desert areas in the southwest (southern Arizona, New Mexico,\nwestern Texas) have the warmest day of the year in June. (For the Big Bend\narea in Texas, it's even in the _first_ half of June, which has different\nreasons; I'm no expert on the climate of the region, but according to [ a\ncomment by David Hammen\n](https:\/\/earthscience.stackexchange.com\/questions\/7233\/why-does-winter-get-\ncolder-after-the-solstice\/7234?noredirect=1#comment59315_7234) , it's _due to\nthe North American Monsoon. July and August are much cloudier (and\noccasionally, much more rainy) than is June in the Big Bend area_ ). There is\na corresponding map for coldest day of the year:\n\n[ ![Coldest day of the year](https:\/\/i.sstatic.net\/46JC8.jpg)\n](https:\/\/i.sstatic.net\/46JC8.jpg)  \n(Source: [ NCEI ](https:\/\/www.ncdc.noaa.gov\/news\/when-to-expect-coldest-day-\nof-year) )\n\nThe detailed structure is somewhat different, which has to due with local\nclimate and circulation, but the overall trend related to humidity and\nproximity to ocean shows up in both. We can also see the mountains, which I\nwould guess to be a snow albedo feedback effect (ever notice how nights get\ncolder when the ground is snow-covered?). At NCEI you will also find [ similar\nmaps for the rest of the USA ](https:\/\/www.ncdc.noaa.gov\/news\/when-to-expect-\ncoldest-day-of-year) as well as [ updated information focussing on the\n1991-2020 timeframe ](https:\/\/www.ncei.noaa.gov\/news\/when-expect-warmest-day-\nyear) ."}
{"query":"My son wants to replicate some experiments and try to grow plants in Martian soil for his A-level science project. I know NASA have managed to produce soil that mimics Martian soil, however I also know how expensive it is.\n\nMy question is, what is the closest proxy to real Martian soil that I can create using readily available supplies from builders merchants, garden suppliers, chemists, and supermarkets?","reasoning":"The post wants to know the ingredients to make martian soil. The anwser gave it a list of ingredients and their percentage in composing it. ","id":"8","excluded_ids":["N\/A"],"gold_ids_long":["make_martian_dirt\/How_to_make_simulant_Martian_dirt.txt"],"gold_ids":["make_martian_dirt\/How_to_make_simulant_Martian_dirt2.txt"],"gold_answer":"$\\begingroup$\n\nthe other posters are correct - true Martian soil contains perchlorates, high\nlevels of iron, and can be highly toxic. What you want to look for is called\n\"Mars Regolith Stimulant\". There are a few websites that have recipes.\n\n[ https:\/\/reprage.com\/post\/home-made-simulant-mars-dirt\n](https:\/\/reprage.com\/post\/home-made-simulant-mars-dirt)\n\n> The five most abundant ingredients, account for almost 90% of the dirt taken\n> from Mars samples.\n>\n>   * SiO2 - 49.5%\n>   * Fe2O3 - 17.9%\n>   * Al2O3 - 7.2%\n>   * MgO - 7.7%\n>   * CaO - 6.7%\n>\n\n>\n> That seems like a good starting point. If I pad those out to reach 100% and\n> use the results as a weight ratio, it should make a decent first batch of\n> home-made Martian soil. Luckily most of this stuff can be found in hardware\n> and health food stores.\n>\n> SiO2\n>\n> Silicon dioxide, yeah sand. You can go budget and get a bag of propagation\n> sand (it won\u2019t be 100% silica). If you want a bit more precision you can\n> hunt around for educational or scientific samples that contain less\n> impurities. You can get 2.7 kilograms for about \\$16\n>\n> Fe2O3\n>\n> Iron oxide, is red cement colouring and is often advertised as red oxide or\n> similar. You can get 2.2 kilograms for about \\$20\n>\n> Al2O3\n>\n> Aluminium oxide, is used as an abrasive. It gets stuck to sandpaper and is\n> used in sandblasting. It was a bit difficult obtaining smaller amounts in\n> Australia (places wanted to sell me 20kg bags). You can get 340 grams for\n> about \\$10.\n>\n> MgO\n>\n> Magnesium oxide, is a dietary supplement found in health food stores. You\n> can get 225 grams for about \\$10.\n>\n> CaO\n>\n> Calcium oxide, Now this one is tricky. I couldn\u2019t easily buy calcium oxide.\n> It seems that calcium oxide reacts with CO2 in the air and gets converted\n> into calcium carbonate. But you can buy calcium carbonate (CaCO3) as a\n> dietary supplement. This can then be turned into calcium oxide by \u2018lime-\n> burning\u2019, just heat it up in a kiln to above 825\u00b0C. You can get 340 grams of\n> calcium carbonate for about \\$10\n\nand others that lets you buy your own (I won't link to them because of\nadvertising, but the Martian garden is one such site). I think you could get\nclose with the above recipe.\n\nIn any scenario, I would strongly recommend supervising your child when they\nare working with the stimulant. It should be handled with gloves and a\nrespirator mask. Ingestion is very dangerous, and it might not be the worst\nidea to check the number of your local poison control center. While this may\nseem like overkill, it would make a great section of your child's science\nproject. \"Methodology\", \"Safety\", and \"Standards & Practices\" are all very\nimportant parts of working in a lab and in engineering.\n\nBest of luck!"}
{"query":"In the United States, the upcoming autumnal equinox is marked on most calendars as the \"first day of autumn.\" Similarly the solstices are commonly called the \"first day of summer\" and \"first day of winter.\" However in most other languages -- and even in older discussions in English -- the solstices have names like \"Midsummer's Day\" and \"Midwinter's Day.\"\n\nIs there some sound reason (e.g. typical temperatures, asymmetrical sunrise\/sunset times, thermal inertia, etc.) to consider a solstice as the first day of a new season, rather than the middle?\n\nAlso (perhaps less on-topic) is there any record of when the change in nomenclature took place in the U.S.? Are there similar discrepancies in other English-speaking countries or in other cultures?","reasoning":"The post is confused about the naming of some seasonal checkpoints, doubting that they may not precisely describe the real season is. The anwser gave a expaination that it may due to a seasonal lag, and gave some ways to reckon seasons. ","id":"9","excluded_ids":["N\/A"],"gold_ids_long":["start_of_a_season\/Season.txt","start_of_a_season\/Seasonal_lag.txt","start_of_a_season\/Growing_season.txt"],"gold_ids":["start_of_a_season\/Growing_season1.txt","start_of_a_season\/Growing_season3.txt","start_of_a_season\/Season1.txt","start_of_a_season\/Season2.txt","start_of_a_season\/Season3.txt","start_of_a_season\/Growing_season2.txt"],"gold_answer":"$\\begingroup$\n\nThere are three main ways to reckon [ seasons\n](http:\/\/en.wikipedia.org\/wiki\/Season) :\n\n  * **Solar.** The 3 months with the greatest insolation are designated summer, so the solstices and equinoxes fall in the middle of the season. In the Celtic calendar, summer started on 1 May; in the traditional Chinese calendar it is [ 5-7 May ](https:\/\/en.wikipedia.org\/wiki\/Lixia) . The cultural 'Midsummer' and 'Midwinter' festivals reflect this. \n  * **Astronomical.** The solstices and equinoxes are the starts of the seasons, with summer starting on about 21 June ( [ it varies ](http:\/\/en.wikipedia.org\/wiki\/Solstice) ). Its use dates back at least to the Romans, and it's used in most western cultures today (apparently not in Russia, Australia, or New Zealand). \n  * **Meteorological.** This is what professional meteorologists use (e.g. [ UK Met Office ](http:\/\/www.metoffice.gov.uk\/climate\/uk\/summaries\/2014\/summer) ), and is based on the prevailing weather on land at mid-latitudes. Seasons are 3 months long and summer starts on 1 June. \n\nI've tried to illustrate the relationships with insolation and temperature\nhere:\n\n![Different ways to reckon seasons](https:\/\/i.sstatic.net\/gWNb5.png)\n\nThere are some other ways too:\n\n  * **Ecological.** Scientists who study the behaviour of organisms (hibernation, blooming, etc.) adapt to the local climate, [ sometimes using 6 seasons ](http:\/\/seasons2011.blogspot.ca\/2011\/06\/ecological-seasons.html) in temperature zones, or only 2 in polar and tropical ones. \n  * **Agricultural.** This would centre around [ the growing season ](http:\/\/en.wikipedia.org\/wiki\/Growing_season) and therefore, in North America and Europe at least, around frost. \n  * **Cultural.** What people think of as 'summer', and what they do outdoors (say), generally seems to line up with local weather patterns. In my own experience, there's no need for these seasons to even be 3 month long; When I lived in Calgary, summer was July and August (hiking), and winter was December to March (skiing). [ Here's another example ](http:\/\/www.bom.gov.au\/iwk\/yawuru\/index.shtml) of a 6-season system, and [ a 3-season system ](http:\/\/www.bom.gov.au\/iwk\/maung\/index.shtml) , from the Aboriginal people of Australia, all based on weather. \n\nWhy do systems with later season starting dates prevail today? Perhaps because\nat mid-latitudes, the [ seasonal lag\n](http:\/\/en.wikipedia.org\/wiki\/Seasonal_lag) means that the start of seasonal\nweather is weeks later than the start of the 'insolation' period. In a system\nwith no [ heat capacity ](http:\/\/en.wikipedia.org\/wiki\/Heat_capacity) , there\nwould be no lag. In systems with high heat capacity, like the marine\nenvironment, the lag may be several months (Ibid.). Here's what the lag looks\nlike in three mid-latitude cities:\n\n![Seasonal lag. Licensed CC-BY-SA by EOEarth](https:\/\/i.sstatic.net\/jOEgw.png)\n\nThe exact same effect happens on a [ diurnal\n](http:\/\/en.wikipedia.org\/wiki\/Diurnal_temperature_variation) (daily) basis\ntoo \u2014 the warmest part of the day is often not midday (or 1 pm in summer). As\nwith the seasons, there are lots of other factors too, but the principle is\nthe same.\n\nThese aren't mutually exclusive ways of looking at it \u2014 there's clearly lots\nof overlap here. Cultural notions of season are surely rooted in astronomy,\nweather, and agriculture."}
{"query":"Why is the sea level in Hudson Bay decreasing so much? Hudson Bay is pretty far up north, much closer to glaciers. Would it make sense for it to recede at this level with sources of fresh water relatively close?","reasoning":"The post is confused why the relative sea level falls in hudson bay. The anwser reveals that it's a phenomenon of post-glacial isostatic rebound.","id":"10","excluded_ids":["N\/A"],"gold_ids_long":["falling_sea_level_in_hudson_bay\/Post-glacial_rebound.txt","falling_sea_level_in_hudson_bay\/Last_Glacial_Period.txt"],"gold_ids":["falling_sea_level_in_hudson_bay\/Post-glacial_rebound1.txt","falling_sea_level_in_hudson_bay\/Last_Glacial_Period1.txt","falling_sea_level_in_hudson_bay\/Post-glacial_rebound3.txt","falling_sea_level_in_hudson_bay\/Post-glacial_rebound2.txt","falling_sea_level_in_hudson_bay\/Last_Glacial_Period2.txt","falling_sea_level_in_hudson_bay\/Last_Glacial_Period5.txt","falling_sea_level_in_hudson_bay\/Post-glacial_rebound5.txt","falling_sea_level_in_hudson_bay\/Last_Glacial_Period3.txt","falling_sea_level_in_hudson_bay\/Last_Glacial_Period4.txt","falling_sea_level_in_hudson_bay\/Post-glacial_rebound4.txt"],"gold_answer":"$\\begingroup$\n\n**The area is experiencing[ post-glacial isostatic rebound\n](https:\/\/en.wikipedia.org\/wiki\/Post-glacial_rebound) . **\n\nMuch of Canada was covered in an extensive ice sheet in the [ last glacial\nperiod ](https:\/\/en.wikipedia.org\/wiki\/Last_glacial_period) (the 'Ice Age'),\nfrom about 110 ka until 12 ka. The ice in the Hudson Bay area was among the\nlast to melt:\n\n![Ice retreat in North America](https:\/\/i.sstatic.net\/FEFew.png)\n\nA thick ice sheet depresses the crust (the lithosphere), making a small dent\nin the uppermost mantle (the [ asthenosphere\n](https:\/\/en.wikipedia.org\/wiki\/Asthenosphere) ) in the process. Well, not\nthat small: p 375 in [ Gornitz\n](https:\/\/books.google.ca\/books?id=yRMgYc-8mTIC) (2009, _Encyclopedia of\nPaleoclimatology and Ancient Environments_ ) says it could be 800 m for a 3000\nmetre-thick ice sheet!\n\nSince the asthenosphere is highly viscous, it takes a long time time for the\ndepression to 'bounce' back up. This map from Natural Resources Canada shows\nthe current rate:\n\n![Isostatic rebound rate in Canada](https:\/\/i.sstatic.net\/kd0gN.jpg)\n\nSince _global_ sea-level is [ currently rising\n](https:\/\/en.wikipedia.org\/wiki\/Current_sea_level_rise) at about 3 mm\/a, a\n_local_ uplift at this rate will break even. Anything more will result in\nrelative sea-level fall, as we see in Hudson Bay (as well as in Scandinavia,\nthe UK, Alaska, and elsewhere \u2014 [ this map is wonderful\n](https:\/\/tidesandcurrents.noaa.gov\/sltrends\/sltrends.html) ).\n\nInteresting, for geologists anyway, is the sedimentological record this\nleaves. I love this example of raised beaches and a small delta experiencing [\nforced regression\n](https:\/\/www.sepmstrata.org\/Terminology.aspx?id=forced%20regression) on the\nshores of Hudson Bay:\n\n![Forced regression of small delta](https:\/\/i.sstatic.net\/5ugZd.jpg)\n\nLast thing \u2014 you asked:\n\n> Would it make sense for it to recede at the level that it is receding with\n> sources of freshwater relatively close?\n\nSince Hudson Bay is connected to the world's ocean, mainly through Hudson\nStrait, the runoff into the Bay has no measurable effect on the water level.\n\n**Credit** [ Ice retreat map\n](https:\/\/commons.wikimedia.org\/wiki\/File:Retrait_des_glaces_en_Am%C3%A9rique.svg)\nby TKostolany, licensed CC-BY-SA. Rebound map by NRCan, free of copyright.\nGoogle Maps image contains own credit."}
{"query":"Are clouds a solid, liquid, or gas?\n\nI have been looking online and they are often described ambiguously as a \"mass\". For instance, from NASA:\n\nA cloud is a mass of water drops or ice crystals suspended in the atmosphere. Clouds form when water condenses in the sky. The condensation lets us see the water vapor. There are many different types of clouds. Clouds are an important part of Earth\u2019s weather and climate.\n\nSince they describe it as a vapor, that makes me think it is indeed a gas. But condensation is by definition the change of state from a gas to a liquid. So that makes it sound like it could be a liquid, or contain liquid droplets rather than \"freely moving\" molecules that typically make up a gas.\n\nBut at another web site, which doesn't seem all that authoritative, it says that clouds are a solid, liquid, and gas simultaneously!\n\nA cloud is a liquid, a solid, and a gas.\n\nThat does seem intriguing. If I remember correctly, liquids are supposed to be incompressible, and clouds are likely compressible.","reasoning":"The post wondered that whether the cloud is gas\/liquid\/solid. The anwser gives a explaination that the cloud is a mixture of them","id":"11","excluded_ids":["N\/A"],"gold_ids_long":["composition_of_cloud\/Cloud_condensation_nuclei.txt"],"gold_ids":["composition_of_cloud\/Cloud_condensation_nuclei4.txt","composition_of_cloud\/Cloud_condensation_nuclei1.txt","composition_of_cloud\/Cloud_condensation_nuclei3.txt","composition_of_cloud\/Cloud_condensation_nuclei2.txt"],"gold_answer":"$\\begingroup$\n\nThe cloud that you see is a mixture of solids and liquids. The liquid is water\nand the solids are ice, [ cloud condensation nuclei\n](https:\/\/en.wikipedia.org\/wiki\/Cloud_condensation_nuclei) and ice\ncondensation nuclei (tiny particulates that water and ice condense on). The\ninvisible part of clouds that you cannot see is water vapor and dry air. The\nmajority of the cloud is just plain air in which the invisible water vapor is\nmixed with and the very tiny water drops and ice particles are suspended in.\n\nA cloud is a mixture of gas, liquid and solids."}
{"query":"Aside from the fraction of water stored as ice on land and temperature of the water, are there other factors that change sea level, and if so what are is the magnitudes of the these changes?\r\n\r\nFor example, by how much does sediment and soluble matter entering the ocean change sea level? What about volcanoes and tectonic activity? Is there a tendency toward hydrostatic equilibrium where the Earth is entirely covered by an ocean of uniform depth?","reasoning":"The post wants to know other reasons that causes rising of sea level. The anwser lists some examples.","id":"12","excluded_ids":["N\/A"],"gold_ids_long":["sea_level_rising_factor\/Sea_level_rise.txt"],"gold_ids":["sea_level_rising_factor\/Sea_level_rise3.txt","sea_level_rising_factor\/Sea_level_rise2.txt","sea_level_rising_factor\/Sea_level_rise6.txt","sea_level_rising_factor\/Sea_level_rise4.txt","sea_level_rising_factor\/Sea_level_rise5.txt","sea_level_rising_factor\/Sea_level_rise1.txt"],"gold_answer":"$\\begingroup$\n\nYes, there are lots of other factors.\n\nFactors affecting sea levels are no different from other natural processes:\nthere is a large number of coupled, non-linear effects, operating on every\ntime scale, and at every length scale, and across many orders of magnitude.\n\nThe Wikipedia page [ Current sea level rise\n](http:\/\/en.wikipedia.org\/wiki\/Current_sea_level_rise) lists many of the known\nprocesses. And I wrote a blog post, [ Scales of sea-level change\n](http:\/\/www.agilegeoscience.com\/journal\/2011\/4\/11\/scales-of-sea-level-\nchange.html) , a couple of years ago with a long list, mostly drawn from Emery\n& Aubrey (1991). Here's the table from it:\n\n![Factors affecting global sea levels](https:\/\/i.sstatic.net\/hqb0B.png)\n\n**Reference** Emery, K & D Aubrey (1991). _Sea-Levels, Land Levels and Tide\nGauges._ Springer-Verlag, New York, 237p."}
{"query":"We all know that as waves approach the shallow shores, the waves begin to form a characteristic shape. The upper portion of these breaking waves appears to curl forward and downwards over the bottom segment of the wave, before breaking into \"white wash\". The image below illustrates what this characteristic shape looks like:\n\nSo why do waves form this characteristic breaking shape as they approach the shallow shores?","reasoning":"The post wants to know why the sea wave is of a certain shape. The phenomenon is wave shoaling, which can be inferred by dispersion relationship.","id":"13","excluded_ids":["N\/A"],"gold_ids_long":["shape_of_waves\/Wave_shoaling.txt","shape_of_waves\/Dispersion_%28water_waves%29.txt"],"gold_ids":["shape_of_waves\/Wave_shoaling1.txt","shape_of_waves\/Dispersion_%28water_waves%297.txt","shape_of_waves\/Dispersion_%28water_waves%294.txt","shape_of_waves\/Dispersion_%28water_waves%291.txt","shape_of_waves\/Dispersion_%28water_waves%296.txt","shape_of_waves\/Dispersion_%28water_waves%293.txt","shape_of_waves\/Wave_shoaling4.txt","shape_of_waves\/Dispersion_%28water_waves%295.txt","shape_of_waves\/Wave_shoaling3.txt","shape_of_waves\/Dispersion_%28water_waves%292.txt","shape_of_waves\/Wave_shoaling2.txt"],"gold_answer":"$\\begingroup$\n\nThe physical process you describe is known as [ wave shoaling\n](http:\/\/en.wikipedia.org\/wiki\/Wave_shoaling) .\n\nAt the basic level, waves propagating into shallow water become shorter and\nhigher, and consequently, steeper. In shallow water, the water particles near\nthe crest move **forward** faster than those below them. Similarly, the\nparticles near the trough move **backward** faster than those above them. This\ncauses strong shearing of the near-surface body of water, eventually forming a\nplunging breaker, or a surf wave. For small-slope (linear) and inviscid (no\nfriction) waves, the above is a consequence of the bottom boundary condition\nfor the water velocity to be zero at the sea floor.\n\nThere are two fundamental and related properties of water waves that\ncontribute to shoaling. One is the wave frequency $\\omega$ remaining constant\nas the depth $d$ decreases. Think of this as the conservation of wave crests\nat any fixed point. However, the wavenumber $k$ (wavelength $\\lambda$) must\nincrease (decrease) with decreasing depth, as per the [ dispersion\nrelationship ](http:\/\/en.wikipedia.org\/wiki\/Dispersion_%28water_waves%29) of\nwater waves (neglecting the effects of viscosity):\n\n$$\\omega^{2} = gk\\tanh{(kd)}$$\n\nwhere $g$ is gravitational acceleration. In shallow water, the dispersion\nrelationship reduces to:\n\n$$\\omega = \\sqrt{gd}k $$\n\nand phase speed $C_p$ and group velocity $C_g$ are both proportional to the\nsquare root of the water depth:\n\n$$ C_p = \\dfrac{\\omega}{k} = \\sqrt{gd} $$\n\n$$ C_g = \\dfrac{\\partial\\omega}{\\partial k} = \\sqrt{gd} $$\n\nIndividual wave crests propagate with phase speed $C_p$. Wave groups and wave\nenergy propagate with group velocity $C_g$. Thus, waves entering shallow water\nbecome **shorter** and **slower** . The second important property leading to\nshoaling is the conservation of wave energy flux, which is proportional to the\ngroup velocity and wave energy:\n\n$$\\dfrac{\\partial(C_{g}E)}{\\partial x}=0$$\n\nBecause the group velocity decreases, the wave energy (read: height) must\nincrease (locally). This causes the waves to grow in height as they enter\nshallow water. As pointed out by @IsopycnalOscillation in a comment above, the\nseparation of water particles from the wave crests happen because the\nindividual orbital velocities at the top of the crest exceed by far the phase\nspeed of the wave.\n\nAlthough bottom friction is significant and non-negligible in shallow water,\nit does not cause shoaling. Mathematically, wave shoaling can occur for\ncompletely inviscid and small-slope (linear) waves that propagate into water\nof decreasing depth."}
{"query":"Messing around on Google Earth recently I noticed a number of striations in the Eastern Pacific. These appear in an East-West orientation and seem to start on the North and South American continental shelves, and extend for roughly half the Pacific Ocean. For example one of these striations start in Santa Rosa Island off California and ends at Hawaii. These striations also appear to be roughly equally spaced at 8 degree intervals. The North and South American striations are angled with respect to each other and seem to converge at roughly Tahiti.\n\nWhat causes these? I'm a fascinated novice.","reasoning":"The post wants to knwo what the ridges in the pacific ocaean are. They are fraction zones actually","id":"14","excluded_ids":["N\/A"],"gold_ids_long":["ridges_in_eastern_pacific_ocean\/Fracture_zone.txt"],"gold_ids":["ridges_in_eastern_pacific_ocean\/Fracture_zone1.txt","ridges_in_eastern_pacific_ocean\/Fracture_zone2.txt","ridges_in_eastern_pacific_ocean\/Fracture_zone3.txt","ridges_in_eastern_pacific_ocean\/Fracture_zone4.txt"],"gold_answer":"$\\begingroup$\n\n**They are[ fracture zones ](https:\/\/en.wikipedia.org\/wiki\/Fracture_zone) . **\n\nI've annotated your image with the names of these very long, tectonically\nimportant features. They even have names, such as the [ Mendocino Fracture\nZone ](https:\/\/en.wikipedia.org\/wiki\/Mendocino_Fracture_Zone) :\n\n[ ![Fracture zones in the northeastern\nPacific](https:\/\/i.sstatic.net\/ceZqX.jpg) ](https:\/\/i.sstatic.net\/ceZqX.jpg)\n\nI also labelled some survey tracks (rather subtle, very straight, very regular\nin width), which are data artifacts \u2014 these are the things you noticed\nradiating from the vicinity of Los Angeles.\n\nThere are yet other types of linear feature on the sea floor:\n\n  * [ Transform faults ](https:\/\/en.wikipedia.org\/wiki\/Transform_fault) are strike-slip faults connecting segments of spreading centres in the oceanic crust. \n  * The [ spreading centres ](https:\/\/en.wikipedia.org\/wiki\/Mid-ocean_ridge) themselves. \n  * Roughly linear archipelagos like Hawaii. \n  * The long, curved trenches at [ convergent plate margins ](https:\/\/en.wikipedia.org\/wiki\/Convergent_boundary) . \n\n_Images from Google Maps. Note: I edited this answer substantially after the\nOP clarified the question... and I learned about[ the difference between\ntransform faults and fracture zones\n](http:\/\/www.columbia.edu\/~vjd1\/MOR_transforms.htm) . _"}
{"query":"If I have wind speeds at 80m and 120m above the surface and I am interested in approximating the speed at 100m, is it valid to just average the 80 and 120 speeds? In other words, should I expect wind speed to be a linear function of height or would a nonlinear function be more appropriate?","reasoning":"The post wants to know the speed when different winds combines togeter. The anwser gives a explaination based on wind gredient formulas","id":"15","excluded_ids":["N\/A"],"gold_ids_long":["interpolating_wind_speed\/Wind_gradient.txt"],"gold_ids":["interpolating_wind_speed\/Wind_gradient2.txt","interpolating_wind_speed\/Wind_gradient1.txt","interpolating_wind_speed\/Wind_gradient3.txt","interpolating_wind_speed\/Wind_gradient4.txt"],"gold_answer":"$\\begingroup$\n\nThe content below is based on expressions found in [ Wind gradient\n](https:\/\/en.wikipedia.org\/wiki\/Wind_gradient) from Wikipedia. See that link\nfor more background information.\n\nWind speed as a function of height can be modeled with the following\nexpression:\n\n$$v_2 = v_1 \\left(\\frac{h_2}{h_1}\\right)^a$$\n\nWhere  $v_1$  and  $v_2$  are the wind speeds are heights  $h_1$  and  $h_2$\n,  $a$  is a parameter related to the atmospheric stability.\n\nGiven your two values for wind speed at different height we want to solve for\n$a$  :\n\n$$a = \\frac{\\ln(v_2\/v_1)}{\\ln(h_2\/h_1)}$$\n\nYou can now use this value, along with the original height \/ wind speed pairs\nto evaluate the wind speed at a different height.\n\nThe model will likely be best when the evaluated hight is between the points\nused to compute  $a$  , basically interpolation will be better than\nextrapolation."}
{"query":"Egypt is planning to create a new delta on the left of the old one by building an artificial river that redirects agricultural waste water into the desert. The water should gradually turn the desert into land that's suitable for agriculture. Here's a video that explains the plan further.\n\nThis ambitious plan will cost around 9 billion euro's to complete. What I don't understand about it though is how simply redirecting water to a desert can turn it into arable land. The Egyptian desert consists of sandy soil and this soil type usually lacks the nutrients necessary for crops to grow. So how will this work?","reasoning":"The post wants to figure out how the aritificial river can make desert arable land. The anwser reveals that not only it provides water, but also will lead some biological precession ","id":"16","excluded_ids":["N\/A"],"gold_ids_long":["artificial_river\/Humus.txt","artificial_river\/Biomass_(ecology).txt","artificial_river\/Soil_conditioner.txt"],"gold_ids":["artificial_river\/Soil_conditioner1.txt","artificial_river\/Biomass_(ecology)1.txt","artificial_river\/Soil_conditioner5.txt","artificial_river\/Humus1.txt","artificial_river\/Humus3.txt","artificial_river\/Biomass_(ecology)5.txt","artificial_river\/Soil_conditioner3.txt","artificial_river\/Humus6.txt","artificial_river\/Soil_conditioner2.txt","artificial_river\/Biomass_(ecology)7.txt","artificial_river\/Biomass_(ecology)6.txt","artificial_river\/Humus2.txt","artificial_river\/Biomass_(ecology)3.txt","artificial_river\/Biomass_(ecology)2.txt","artificial_river\/Humus4.txt","artificial_river\/Soil_conditioner4.txt","artificial_river\/Biomass_(ecology)4.txt","artificial_river\/Humus5.txt"],"gold_answer":"$\\begingroup$\n\nSuch projects take time to fully achieve their aims. In addition to providing\nwater, the sand will need to undergo a process of [ soil conditioning\n](https:\/\/en.wikipedia.org\/wiki\/Soil_conditioner) . This will include the\nprogressive addition of [ biomass ](https:\/\/en.wikipedia.org\/wiki\/Biomass) , [\nhumus ](https:\/\/en.wikipedia.org\/wiki\/Humus) and compost. This will include a\nmeans of water retention, which may include the application of clay or slit\neither mechanically or via the outflow of the Nile River."}
{"query":"According to textbook knowledge, the mass of the earth is about 6\u00d71024kg\r\n. How is this number determined when one cannot just weight the earth using regular scales?","reasoning":"The post wants to find the mass of the Earth. By using the law of universal gravitation and law of motion, we can solve that. ","id":"17","excluded_ids":["N\/A"],"gold_ids_long":["mass_of_earth\/Newton%27s_laws_of_motion.txt","mass_of_earth\/Newton%27s_law_of_universal_gravitation.txt"],"gold_ids":["mass_of_earth\/Newton%27s_laws_of_motion2.txt","mass_of_earth\/Newton%27s_laws_of_motion1.txt","mass_of_earth\/Newton%27s_law_of_universal_gravitation7.txt","mass_of_earth\/Newton%27s_law_of_universal_gravitation5.txt","mass_of_earth\/Newton%27s_laws_of_motion8.txt","mass_of_earth\/Newton%27s_law_of_universal_gravitation8.txt","mass_of_earth\/Newton%27s_law_of_universal_gravitation1.txt","mass_of_earth\/Newton%27s_laws_of_motion6.txt","mass_of_earth\/Newton%27s_law_of_universal_gravitation9.txt","mass_of_earth\/Newton%27s_laws_of_motion3.txt","mass_of_earth\/Newton%27s_laws_of_motion4.txt","mass_of_earth\/Newton%27s_laws_of_motion5.txt","mass_of_earth\/Newton%27s_law_of_universal_gravitation4.txt","mass_of_earth\/Newton%27s_law_of_universal_gravitation6.txt","mass_of_earth\/Newton%27s_laws_of_motion7.txt","mass_of_earth\/Newton%27s_law_of_universal_gravitation2.txt","mass_of_earth\/Newton%27s_laws_of_motion9.txt","mass_of_earth\/Newton%27s_law_of_universal_gravitation3.txt"],"gold_answer":"$\\begingroup$\n\nAccording to **Newton's Law of Gravity** based on attractive force\n(gravitational force) that two masses exert on each other:\n\n$$F=\\frac{GmM}{r^2}$$\n\nWhere:\n\n  * $F$  is the gravitational force \n  * $G = 6.67 \\times 10^{-11}\\ \\mathrm{m}^3\\ \\mathrm{kg}^{-1}\\ \\mathrm{s}^{-2}$  is a constant of proportionality \n  * $M$  and  $m$  are the two masses exerting the forces \n  * $r$  is the distance between the two centers of mass. \n\nFrom **Newton's second law of motion** :\n\n$$F=ma$$\n\nWhere:\n\n  * $F$  is the force applied to an object \n  * $m$  is the mass of the object \n  * $a$  is its acceleration due to the force. \n\n**Equating both the equations** :\n\n$$F = \\frac{GmM}{r^2} = ma$$\n\n$$\\frac{GM}{r^2}= a$$  (The  $m$  's canceled out.)\n\nNow solve for  $M$  , the mass of the Earth.\n\n$$M = \\frac{ar^2}{G}$$\n\nWhere  $a = 9.8\\ \\mathrm{m}\\ \\mathrm{s}^{-2}$  ,  $r = 6.4 \\times 10^6\\\n\\mathrm{m}$  , and  $G = 6.67 \\times 10^{-11}\\ \\mathrm{m}^3\\ \\mathrm{kg}^{-1}\\\n\\mathrm{s}^{-2}$  .\n\n$$M = 9.8 \\times (6.4 \\times 10^6)^2\/(6.67 \\times 10^{-11})\\ \\mathrm{kg}$$\n\n* * *\n\nHence,\n\n##  $M = 6.0 \\times 10^{24}\\ \\mathrm{kg}$"}
{"query":"My question refers to the current process of climate change. CO2 is rising, which leads to the greenhouse effect, which raises temperatures. This leads to more wildfires, which reduces number of trees, increasing CO2 and reducing CO2 capacity absorption. Ice caps start to melt, which reduces sunlight reflection (less snow), trapping more heat on atmosphere. Water rises, taking over land and trees, further enhancing the CO2 absorption capacity. Oceans acidify, lowering their CO2 absorption capacity too. Etc etc.\r\n\r\nIt seems the process of climate change is a \"vicious circle\", with a lot of feedback loops reinforcing the trends.\r\n\r\nIs this the case? Are there counteracting forces that go against this circle?","reasoning":"The post wants to know whether the climate change is purely a negative phenomenon. The anwser gives some pros and cons of climate change, indicating that it's not just a negative thing.","id":"18","excluded_ids":["N\/A"],"gold_ids_long":["vicous_climate_change\/Climate_change_feedbacks.txt"],"gold_ids":["vicous_climate_change\/Climate_change_feedbacks4.txt","vicous_climate_change\/Climate_change_feedbacks6.txt","vicous_climate_change\/Climate_change_feedbacks3.txt","vicous_climate_change\/Climate_change_feedbacks5.txt"],"gold_answer":"$\\begingroup$\n\nThere are indeed a lot of positive feedback mechanisms, i.e. a warm climate\nleads to a warmer climate. From [ this Wikipedia article\n](https:\/\/en.wikipedia.org\/wiki\/Climate_change_feedback) , they are:\n\n  * Carbon cycle feedbacks \n  * Cloud feedback \n  * Gas release \n  * Ice-albedo feedback \n  * Water vapor feedback \n\nHowever, there are also a few negative feedbacks (same source):\n\n  * Blackbody radiation \n  * Carbon cycle \n  * Lapse rate \n  * Impacts on humans \n\nNow the question is: what is the net budget between positive and negative\nfeedbacks? To assess this, climatologists use some metrics, the main ones\nbeing \"transient climate response\" (TCR) and \"equilibrium climate sensitivity\"\n(ECS). From [ Knutti et al. (2017) ](https:\/\/doi.org\/10.1038\/ngeo3017) :\n\n> TCR is defined as the global mean surface warming at the time of doubling of\n> CO  $_2$  in an idealized 1% yr  $^{\u22121}$  CO  $_2$  increase experiment, but\n> is more generally quantifying warming in response to a changing forcing\n> prior to the deep ocean being in equilibrium with the forcing. Based on\n> state-of-the-art climate models, and instrumentally recorded warming in\n> response to CO  $_2$  and other anthropogenic and natural forcings, the\n> Intergovernmental Panel on Climate Change's Fifth Assessment Report (IPCC\n> AR5) assessed that the transient climate response is 'likely' (>66%\n> probability) to be in the range of 1 \u00b0C to 2.5 \u00b0C.\n>\n> By contrast, the equilibrium climate sensitivity (ECS) is defined as the\n> warming response to doubling CO  $_2$  in the atmosphere relative to pre-\n> industrial climate, after the climate reached its new equilibrium, taking\n> into account changes in water vapour, lapse rate, clouds and surface albedo.\n> [...] The estimated range of ECS has not changed much despite massive\n> research efforts. The IPCC assessed that it is 'likely' to be in the range\n> of 1.5 \u00b0C to 4.5 \u00b0C.\n\nWhich basically means that the climate will get warmer in the future, until it\nwill eventually reach some kind of equilibrium."}
{"query":"I've seen models in astronomy that show how the Earth-Moon system must have come together after a collision. However, I have not heard whether there is any actual physical evidence on Earth that points to a prior collision. Is there geological (or other physical) evidence here on Earth that confirms the moon originated from a collision on Earth? If so what is that evidence?","reasoning":"The post wants to know if there are any evidence which may proov the moon collided with the earth once. The fact that the collision is only a theory. ","id":"19","excluded_ids":["N\/A"],"gold_ids_long":["moon_collided_with_earth\/Giant-impact_hypothesis.txt"],"gold_ids":["moon_collided_with_earth\/Giant-impact_hypothesis1.txt","moon_collided_with_earth\/Giant-impact_hypothesis2.txt","moon_collided_with_earth\/Giant-impact_hypothesis3.txt","moon_collided_with_earth\/Giant-impact_hypothesis8.txt","moon_collided_with_earth\/Giant-impact_hypothesis9.txt","moon_collided_with_earth\/Giant-impact_hypothesis7.txt","moon_collided_with_earth\/Giant-impact_hypothesis6.txt","moon_collided_with_earth\/Giant-impact_hypothesis5.txt","moon_collided_with_earth\/Giant-impact_hypothesis4.txt"],"gold_answer":"$\\begingroup$\n\n> Is there geological (or other physical) evidence here on Earth that confirms\n> the moon once collided with the Earth?\n\nNo, there isn't. This is, however, plenty of evidence that the moon formed due\nto a collision of a third body (sometimes referred to as Theia) with the\nEarth, and the moon formed from the ring of debris that resulted from the\ncollision.\n\nThis theory is often known as the _[ Giant Impact Hypothesis\n](http:\/\/en.wikipedia.org\/wiki\/Giant_impact_hypothesis) _ and searching for\nthis term may help you find other links and references elsewhere.\n\n> If so what is that evidence?\n\nTo summarise the geological evidence, much of it is **indirect** evidence, in\nthat it compares geology on the Moon with similar geology or features on the\nEarth, and draws conclusions to explain the similarities (or discrepancies).\n\nBecause of the sheer size of the proposed impact, it would have likely\nreconfigured the surfaces of both bodies entirely, and so finding direct\nphysical evidence on the Earth would be extremely unlikely. (e.g. a massive\nhidden crater would simply no longer exist)\n\n##  Geological Evidence\n\n  * Moon rocks collected from the Apollo missions that have almost identical oxygen isotope ratios to similar rocks found on Earth of the same age. \n  * A large portion of the Lunar crust is made up of Anorthosite, which is indicative of a large melting event. (with the energy for this supplied from the impact) \n  * Zinc. Lunar rocks contain less zinc, but with heavier _isotopes_ of Zn than those found on Earth, which by contrast has lighter isotopes in greater abundance. This is consistent with zinc being depleted from the moon by evaporation, such as during a massive impact event. \n\n  * Density and volatiles. The Moon is 25% less dense than the uncompressed density of Earth. It is severely depleted in volatiles, with practically no water and less than half the potassium abundance that Earth has. The combination of low density and lack of volatiles implies that the Moon was not a simple accretion of early solar system material, but resembles the Earth's mantle in bulk composition. Volatile material would have been vapourised by the impact. \n\n  * The bulk composition of the Moon's crust. (This one does not actually involve the Earth, but I feel it is still important to mention.) The Moon's mantle and crust chemical composition _could_ be explained if the Moon had a large iron core, but its core is actually quite small. \n\n##  Other Physical Evidence\n\n  * The ratio of the Earth and Moon's mass far exceeds any other planet in the solar system, and this begs the question of how did so much material become in orbit of the Earth. (Not evidence as such, but raises the question in the first place) \n\n  * Getting more indirect...there are bands of warm silica-rich dust orbiting nearby stars which is interpreted as planet-sized bodies having collided with each other, so there is precedent for similar events happening elsewhere in the galaxy. (Again, I realise this is one is not strictly answering the question, but Earth Scientists often have to look well outside the Earth to answer their questions!) \n\nHope this gets you started!\n\n**Update:** I recently came across [ this short article\n](http:\/\/www.ox.ac.uk\/news\/science-blog\/where-did-moon-come) , which provides\na summary of some of the latest thinking on the Moon's formation, including\nthe Giant Impact Hypothesis.\n\n_Sources:[ de Pater and Lissauer (2010): Planetary Sciences\n](http:\/\/books.google.co.uk\/books\/about\/Planetary_Sciences.html?id=RaJdy3_VINQC)\n; [ Canup and Asphaug (2001), Nature\n](http:\/\/www.es.ucsc.edu\/~rcoe\/eart206\/canup_Moon_Nature_01.pdf) _"}
{"query":"I am procedurally generating planets for an open world space sandbox game. I am using a rough simulation of tectonic plates to create mountain ranges and other geological features.\n\nA planet surface consists of several plates, which consists of tiles. The continental plates are randomly generated, with random initial elevation and drift velocities assigned.\n\nTile elevations are generated by multiplying an envelope ( e^{ -d^2 } ) with a function for different types of plate boundaries and relative drift velocities.\n\nFor the sake of realism, is it possible to have a land-ocean divergent plate boundary? I could not find anything online. There also doesn't seem to be any examples on Earth from what I could find. Is it safe to assume that divergent boundaries only occur between land-land and ocean-ocean plate boundaries?","reasoning":"The post wants to generate some ocean-continent boundaries. The anwser is no since the boundaries are formed themselves.","id":"20","excluded_ids":["N\/A"],"gold_ids_long":["ocean_continent_divergent_boundary\/Triple_junction.txt","ocean_continent_divergent_boundary\/Mid-ocean_ridge.txt","ocean_continent_divergent_boundary\/Plate_tectonics.txt"],"gold_ids":["ocean_continent_divergent_boundary\/Triple_junction4.txt","ocean_continent_divergent_boundary\/Triple_junction5.txt","ocean_continent_divergent_boundary\/Mid-ocean_ridge1.txt","ocean_continent_divergent_boundary\/Mid-ocean_ridge6.txt","ocean_continent_divergent_boundary\/Mid-ocean_ridge7.txt","ocean_continent_divergent_boundary\/Plate_tectonics3.txt","ocean_continent_divergent_boundary\/Plate_tectonics5.txt","ocean_continent_divergent_boundary\/Triple_junction2.txt","ocean_continent_divergent_boundary\/Mid-ocean_ridge2.txt","ocean_continent_divergent_boundary\/Mid-ocean_ridge3.txt","ocean_continent_divergent_boundary\/Triple_junction3.txt","ocean_continent_divergent_boundary\/Plate_tectonics7.txt","ocean_continent_divergent_boundary\/Mid-ocean_ridge4.txt","ocean_continent_divergent_boundary\/Plate_tectonics4.txt","ocean_continent_divergent_boundary\/Plate_tectonics9.txt","ocean_continent_divergent_boundary\/Plate_tectonics6.txt","ocean_continent_divergent_boundary\/Plate_tectonics2.txt","ocean_continent_divergent_boundary\/Plate_tectonics8.txt","ocean_continent_divergent_boundary\/Triple_junction1.txt","ocean_continent_divergent_boundary\/Plate_tectonics1.txt","ocean_continent_divergent_boundary\/Mid-ocean_ridge5.txt"],"gold_answer":"$\\begingroup$\n\nThe oceanic plates are themselves formed from the [ divergent boundary\n](https:\/\/en.wikipedia.org\/wiki\/Plate_tectonics) , so probably not. Even if a\nnew rifting occurred exactly at the boundary, the result would eventually be\nthat the ocean floor surrounds the divergent boundary.\n\nA very simplified model of an ocean would have a [ divergent boundary\n](https:\/\/en.wikipedia.org\/wiki\/Mid-ocean_ridge) in the middle. This oceanic\nspreading center might have basaltic volcanic islands along it, and two\nmirrored plates on each sides, pushing towards neighboring continental or\noceanic plates.\n\n[ ![From wikipedia, as usual](https:\/\/i.sstatic.net\/OVQRD.png)\n](https:\/\/i.sstatic.net\/OVQRD.png)\n\nI'm trying to think about any oddity that would fit your description, but\ncan't really come up with a good example. Locally you might have the\nconditions in [ triple junctions\n](https:\/\/en.wikipedia.org\/wiki\/Triple_junction) eg. at Afar Triangle.\nSomehow, it could also describe parts of New Zealand and eastern\nMediterranean, but it's very complex areas with more parameters controlling\nthe rifting.\n\nEarth is not controlled by any simple equation, its formed by 4.56 billion\nyears of interaction between rocks, magma, life, atmosphere and even\nastronomic influence, so I'm not sure that divergent boundary never occurred\nbetween existing continental and oceanic plates, but at least it's very\nuncommon and couldn't last long.\n\nA way to understand plate tectonics better, and maybe even a good inspiration\nfor world building games, is to have a look at the (free) program [ Gplates\n](https:\/\/www.gplates.org\/) that is used by students and scientists to\nsimulate tectonic history. Don't worry about your ignorance, interest is more\nimportant than knowledge. The game might be a good inspiration for someone to\nlearn more about something really [ awesome\n](https:\/\/www.google.com.au\/imgres?imgurl=https%3A%2F%2Fwww.nasa.gov%2Fsites%2Fdefault%2Ffiles%2F1-bluemarble_west.jpg&imgrefurl=https%3A%2F%2Fwww.nasa.gov%2Fcontent%2Fgoddard%2Fearth-\nfrom-space-15-amazing-things-\nin-15-years&docid=t97PKMHHmGUgVM&tbnid=I6mUIX2BemSxbM%3A&vet=1&w=2048&h=2048&noj=1&client=firefox-b&bih=1082&biw=1831&q=earth%20from%20space&ved=0ahUKEwi4sYL4u87RAhWKHZQKHUr8B_QQMwgzKAMwAw&iact=mrc&uact=8)\n."}
{"query":"I remember Journey to the Center of Earth and wonder: What is the deepest in the Earth surface or below sea level we have traveled either by foot, sub, drill or camera?\r\n\r","reasoning":"The post wants to know the deepest surface that human have traveled to in the earth. The anwsers is the Mponeng Gold Mine in South Africa","id":"21","excluded_ids":["N\/A"],"gold_ids_long":["deepest_into_earth\/Mponeng_Gold_Mine.txt"],"gold_ids":["deepest_into_earth\/Mponeng_Gold_Mine1.txt","deepest_into_earth\/Mponeng_Gold_Mine6.txt","deepest_into_earth\/Mponeng_Gold_Mine2.txt","deepest_into_earth\/Mponeng_Gold_Mine5.txt","deepest_into_earth\/Mponeng_Gold_Mine4.txt","deepest_into_earth\/Mponeng_Gold_Mine3.txt"],"gold_answer":"$\\begingroup$\n\nProbably a bit over 4 km, in this South African mine: [\nhttps:\/\/en.wikipedia.org\/wiki\/Mponeng_Gold_Mine\n](https:\/\/en.wikipedia.org\/wiki\/Mponeng_Gold_Mine) But as the link mentions,\nthe mine operators go to considerable lengths to reduce the mine temperature\nto endurable levels from the 66\u00b0C\/151\u00b0F of the surrounding rock.\n\nNote: This answer is for the original question, where the OP asked for the\ndeepest depth below the surface. It's since been changed to ask for depth\nbelow sea level.\n\n[ ![enter image description here](https:\/\/i.sstatic.net\/VwkFT.jpg)\n](https:\/\/i.sstatic.net\/VwkFT.jpg)\n\n[ http:\/\/cracked.tumblr.com\/post\/162183647834\/the-mponeng-gold-mine-in-south-\nafrica-is-the ](http:\/\/cracked.tumblr.com\/post\/162183647834\/the-mponeng-gold-\nmine-in-south-africa-is-the)"}
{"query":"In the movie Into the Storm (2014) near the end, storm chaser Pete sees the eye of a massive tornado.\r\n\r\nIn 1928 (real life), Will Keller was in his barn when a huge tornado passed through. He reported seeing an opening in the center of the tornado \"about 55 feet (17 meters) across and extended some 2,500 feet (762 meters) up.\" Source\r\n\r\nIs there any \"official\" documentation or evidence that tornadoes, especially stronger ones, have eyes like a hurricane does? Or is it just an urban legend?","reasoning":"The post wants to know whether the tornado has an eye in it. By coriolis function we can compute that. ","id":"22","excluded_ids":["N\/A"],"gold_ids_long":["eyes_of_tornadoes\/eye.txt","eyes_of_tornadoes\/Coriolis_force.txt"],"gold_ids":["eyes_of_tornadoes\/eye1.txt","eyes_of_tornadoes\/Coriolis_force1.txt","eyes_of_tornadoes\/eye2.txt","eyes_of_tornadoes\/Coriolis_force4.txt","eyes_of_tornadoes\/Coriolis_force6.txt","eyes_of_tornadoes\/Coriolis_force2.txt","eyes_of_tornadoes\/Coriolis_force8.txt","eyes_of_tornadoes\/Coriolis_force5.txt","eyes_of_tornadoes\/Coriolis_force3.txt","eyes_of_tornadoes\/Coriolis_force9.txt","eyes_of_tornadoes\/Coriolis_force7.txt"],"gold_answer":"$\\begingroup$\n\nYes, if one takes the common meaning of the term [ \"eye of the storm\"\n](http:\/\/glossary.ametsoc.org\/wiki\/Eye) to be the area of relatively low wind\nspeed near the center of the vortex, most tornadoes can be said to have eyes.\nCyclostrophic balance describes a steady-state, inviscid flow with neglected\nCoriolis force:\n\n$$ \\dfrac{v^2}{r} = -\\dfrac{1}{\\rho}\\dfrac{\\partial p}{\\partial n} $$\n\nwhere centripetal force balances radial pressure gradient. Here, $v$ is\ntangential wind speed, $r$ distance from vortex center, $\\rho$ is air density,\n$p$ is atmospheric pressure and $n$ is the radial direction pointing inward.\nFrom here, tangential wind speed is simply:\n\n$$ v = \\sqrt{-\\dfrac{r}{\\rho}\\dfrac{\\partial p}{\\partial n}} $$\n\nsuggesting that $v\\to0$ when $r\\to0$. While the flow in tornadoes is highly\nnon-stationary and subject to friction, this idealized model shows why there\nmust exist an \"eye\" inside a vortex or an area of closed circulation. This\n\"eye\" may or may not be easily recognized by a hypothetical human observer\ninside a tornado."}
{"query":"I have heard from many people that sinks do not empty in a particular pattern depending on what hemisphere you are in, but I have also heard from people who adamant that a sink of water would empty clockwise in one hemisphere and anti-clockwise in another.\n\nWhile I acknowledge the above idea is probably a myth, is there any simple experiment that one can do do determine what hemisphere they are in, utilizing the Coriolis effect, or otherwise?\n\n","reasoning":"Besides using Coriolis effect, the author wonder if there is anthoer simple ways to find the hemisphere you are in. The solution is Foucault pendulum. ","id":"23","excluded_ids":["N\/A"],"gold_ids_long":["determine_hemisphere\/Foucault_pendulum.txt"],"gold_ids":["determine_hemisphere\/Foucault_pendulum5.txt","determine_hemisphere\/Foucault_pendulum2.txt","determine_hemisphere\/Foucault_pendulum1.txt","determine_hemisphere\/Foucault_pendulum4.txt","determine_hemisphere\/Foucault_pendulum3.txt"],"gold_answer":"$\\begingroup$\n\nYou can use the [ Foucault pendulum\n](http:\/\/en.wikipedia.org\/wiki\/Foucault_pendulum) to determine the hemisphere:\nIts plane of movement rotates:\n\n  * anti-clockwise in the southern hemisphere; \n  * clockwise in the northern hemisphere. \n\nThe rotation of the plane can be explained by the Coriolis force."}
{"query":"Are there any estimates of the amount of Uranium there is in Earth's Crust?\r\n\r\nFrom what I know, it's supposed that there are large amounts of Uranium in Earth's Core, the decay of which is responsible for the core maintaining its high temperature. Mining the core is hardly imaginable, while the resources in Crust are more accessible available for mining: so how much is in the Crust, and at what levels of concentration? (which affects the viability of accessing it).","reasoning":"The post wants to know how much Ur  in the Earth. The anwser gave some estimations in different perspectives. ","id":"24","excluded_ids":["N\/A"],"gold_ids_long":["uranium_in_earth\/Uranium.txt"],"gold_ids":["uranium_in_earth\/Uranium4.txt","uranium_in_earth\/Uranium7.txt","uranium_in_earth\/Uranium3.txt","uranium_in_earth\/Uranium5.txt","uranium_in_earth\/Uranium1.txt","uranium_in_earth\/Uranium2.txt","uranium_in_earth\/Uranium8.txt","uranium_in_earth\/Uranium6.txt"],"gold_answer":"$\\begingroup$\n\nAccording to wikipedia, there are around 5.5 million tonnes of [ uranium in\nore deposits ](https:\/\/en.wikipedia.org\/wiki\/Uranium#Resources_and_reserves)\nthat are commercially viable at current prices, and perhaps 35 million tonnes\nthat are potentially viable if prices increase.\n\nAlso according to wikipedia, [ the Earth's crust\n](https:\/\/en.wikipedia.org\/wiki\/Uranium#Biotic_and_abiotic) (to 25 km depth)\ncontains an estimated 10^14 tonnes (100 trillion tonnes), while the oceans may\ncontain 10^10 tonnes (10 billion tonnes). This presumably includes the ore\nfigures stated above.\n\nThe previous link states that \"The decay of uranium, thorium, and potassium-40\nin the Earth's mantle is thought to be the main source of heat\", however no\nestimate is given for quantities. All\u00e8gre, Lewin and Dupr\u00e9 (1988) state that\n\"The concentration of U in the primordial mantle (bulk Earth) has been\ndetermined to be ~21\u00b11 ppb\". Back of the envelope calculations would then give\nus that the [ mantle ](https:\/\/en.wikipedia.org\/wiki\/Mantle_%28geology%29) is\n84% of the [ Earth ](https:\/\/en.wikipedia.org\/wiki\/Earth) by volume (probably\nslightly less than that by mass?), and the mass of the earth is 6*10^21\ntonnes, which would give us, very approximately, 0.84 * (6*10^21) *\n(2.1*10^-8) ~= 10^14 tonnes, or roughly the same as is in the Earth's crust.\n\n  * All\u00e8gre, C.J., Lewin, E. & Dupr\u00e9, B., 1988. [ A coherent crust-mantle model for the uranium-thorium-lead isotopic system. ](https:\/\/www.sciencedirect.com\/science\/article\/pii\/0009254188900940) Chemical Geology, 70(3), pp.211\u2013234."}
{"query":"Someone shared a video with me in which clouds were forming a ring around the Sun. I took this screen shot of that video:\r\n\r\nWhat is the reason behind this?","reasoning":"The post wants to know what the ring around the sun is. It's the 22 degree ring","id":"25","excluded_ids":["N\/A"],"gold_ids_long":["22_halo\/Halo_(optical_phenomenon).txt","22_halo\/22%C2%B0_halo.txt"],"gold_ids":["22_halo\/Halo_(optical_phenomenon)6.txt","22_halo\/22%C2%B0_halo1.txt","22_halo\/Halo_(optical_phenomenon)5.txt","22_halo\/22%C2%B0_halo3.txt","22_halo\/Halo_(optical_phenomenon)3.txt","22_halo\/Halo_(optical_phenomenon)2.txt","22_halo\/Halo_(optical_phenomenon)1.txt","22_halo\/Halo_(optical_phenomenon)7.txt","22_halo\/Halo_(optical_phenomenon)4.txt","22_halo\/22%C2%B0_halo2.txt"],"gold_answer":"$\\begingroup$\n\nThis optical phenomenon is called a [ 22\u00b0 halo\n](https:\/\/en.wikipedia.org\/wiki\/22%C2%B0_halo) which is a subset of other [\nhalos ](https:\/\/en.wikipedia.org\/wiki\/Halo_\\(optical_phenomenon\\)) . This\narises from sunlight refracting through hexagonal ice crystals, which can be\nfound in high level cirrus clouds. Light that would otherwise not make it to\nyour eye enters an ice crystal and then exits at an angle of approximately 22\ndegrees. This produces the arc of light you see in the video. You see\n(inverted) rainbow coloring of the halo because the light is not uniformly\nrefracted but varies from 21.7 degrees for red photons to 22.5 degrees for\nviolet photons.\n\n![enter image description here](https:\/\/i.sstatic.net\/4gojQ.png)  \nImage by donalbein, Wikemedia Commons, CC-By-SA-2.5 [\nhttps:\/\/commons.wikimedia.org\/wiki\/File:Path_of_rays_in_a_hexagonal_prism.png\n](https:\/\/commons.wikimedia.org\/wiki\/File:Path_of_rays_in_a_hexagonal_prism.png)\n\nThere are many more optical phenomenon you can see, but all are based around\nsunlight and the optical properties of ice crystals and water droplets. Here\nis a phenomenal picture taken in winter showing many examples:\n\n![enter image description here](https:\/\/i.sstatic.net\/kv1zw.png)"}
{"query":"It is said about ozone:\n\na layer in the earth's stratosphere at an altitude of about 10 km (6.2 miles) containing a high concentration of ozone\n\nOver the Earth\u2019s surface, the ozone layer\u2019s average thickness is about 300 Dobson Units or a layer that is 3 millimetres thick. (nasa)\n\nSo, how does the Ozone gas stays in that altitude without dissolving?","reasoning":"The post wonder how the ozone stay in the place it should be. The reason behind it is a series of chemical reaction.","id":"26","excluded_ids":["N\/A"],"gold_ids_long":["ozone_layer\/Chlorofluorocarbon.txt","ozone_layer\/Ozone%E2%80%93oxygen_cycle.txt"],"gold_ids":["ozone_layer\/Ozone%E2%80%93oxygen_cycle1.txt","ozone_layer\/Chlorofluorocarbon3.txt","ozone_layer\/Ozone%E2%80%93oxygen_cycle2.txt","ozone_layer\/Chlorofluorocarbon1.txt","ozone_layer\/Chlorofluorocarbon2.txt","ozone_layer\/Chlorofluorocarbon6.txt","ozone_layer\/Chlorofluorocarbon5.txt","ozone_layer\/Chlorofluorocarbon7.txt","ozone_layer\/Ozone%E2%80%93oxygen_cycle3.txt","ozone_layer\/Chlorofluorocarbon8.txt","ozone_layer\/Chlorofluorocarbon4.txt"],"gold_answer":"$\\begingroup$\n\nFor the ozone layer to dissolve, it would need something to bind to. [\nChloroflurocarbons ](https:\/\/en.wikipedia.org\/wiki\/Chlorofluorocarbon) are one\nvery notable thing that it can bind to, but that doesn't exactly answer the\nquestion.\n\nWhile the ozone layer would be 3 mm thick if it was compressed down to the\npressure of earth's surface, since it is further up in the atmosphere, it can\ntake up a larger volume (like 20 km thick). The ozone layer is maintained by\nthe [ Chapman cycle ](http:\/\/glossary.ametsoc.org\/wiki\/Chapman_mechanism) .\n\nThat is, the oxygen molecule (  $\\ce{O_2}$  ) is dissociated by UV radiation\n(photolysis) to oxygen atoms (  $\\ce{2O}$  ). Then the photolyzed oxygen atoms\n(  $\\ce{2O}$  ) can bond with two oxygen molecules (  $\\ce{2O_2}$  ) to make\nan two ozone molecules (  $\\ce{2O_3}$  ), provided another molecule can take\naway some excess energy.\n\nSince it is a cycle, there has to be a way for the ozone to return to oxygen.\nOne ozone molecule (  $\\ce{O_3}$  ) can photolyze to make an oxygen atom (\n$\\ce{O}$  ) and oxygen molecule (  $\\ce{O_2}$  ). The oxygen atom (  $\\ce{O}$\n) can react with another ozone molecule (  $\\ce{O_3}$  ) to make two oxygen\nmolecules (  $\\ce{2O_2}$  ).\n\nTo just answer your question directly, the ozone layer is replenished by the\nsun's UV energy reacting with the oxygen in the atmosphere."}
{"query":"This question asked: What is the evidence it is feasible to reverse ocean acidification by adding large quantities of a base (bicarb soda)?\n\nThe result was:\n\nDanny Harvey of the University of Toronto has already looked into this. His solution is to deposit 4 Gt\/a of limestone into the oceans. To put this in perspective, global coal production in 2013 was nearly double this at 7.823 Gt and it is more than global iron ore production in 2014 of 3.22 Gt.\n\nThe respondent then posed the question: Are there sufficient quantities of easily obtainable limestone to do this?\n\nMy question is: Are there sufficient quantities of limestone to dump in the ocean to reverse acidification?","reasoning":"The post intends to find out limestone's quantity to stop the ocean from being acid. The anwser gave a way to estimate, but it's really hard. ","id":"27","excluded_ids":["N\/A"],"gold_ids_long":["limestone\/Cement.txt","limestone\/Limestone.txt","limestone\/Karst.txt"],"gold_ids":["limestone\/Limestone7.txt","limestone\/Cement7.txt","limestone\/Karst6.txt","limestone\/Karst1.txt","limestone\/Cement8.txt","limestone\/Limestone1.txt","limestone\/Karst5.txt","limestone\/Karst2.txt","limestone\/Limestone3.txt","limestone\/Cement6.txt","limestone\/Karst7.txt","limestone\/Karst3.txt","limestone\/Cement5.txt","limestone\/Cement4.txt","limestone\/Limestone2.txt","limestone\/Cement1.txt","limestone\/Cement3.txt","limestone\/Limestone6.txt","limestone\/Limestone5.txt","limestone\/Karst4.txt","limestone\/Limestone4.txt","limestone\/Cement2.txt"],"gold_answer":"$\\begingroup$\n\nGetting figures on the amount of limestone available is difficult.\n\nApparently \" [ limestone ](https:\/\/en.wikipedia.org\/wiki\/Limestone) makes up\nat least 10% of the total volume of all sedimentary rocks\".\n\nOne way to answer your question is by inference. [ Cement\n](https:\/\/en.wikipedia.org\/wiki\/Cement) is manufactured from limestone.\nCurrent [ global production of cement\n](http:\/\/www.statista.com\/statistics\/373845\/global-cement-production-\nforecast\/) is in excess of 3.27 Gt\/a and by 2030 it is forecast to be\napproximately 4.83 Gt\/a. Thus if all limestone currently earmarked for cement\nproduction were diverted to neutralizing the acidity of the world's oceans it\ncould be done at short notice. How sustainable it would be over the 200 years\nrequired, is another matter. It also raises the question of what happens to\nall the industries and projects that current rely on a cheap and ready supply\nof cement?\n\nWith much tongue in cheek, the Florida peninsular in the US is predominantly\nlimestone, likewise a significant portion of eastern England, with the \"white\ncliffs of Dover, the [ karst ](https:\/\/en.wikipedia.org\/wiki\/Karst) regions of\nthe eastern Adriatic, southern Europe, southern and eastern Asia and the\nNullabor Plain in southern Australia. Would these countries be will to\nsacrifice their lands to neutralize acidity in the worlds oceans?"}
{"query":"I was just reading this about how Hurricane Ethel could have merged with Hurricane Dora in 1964.\n\nHas such a merge ever happened before in history? If so, what was the result? Would storms become twice as powerful? Or would they disrupt and dissipate each other?\n\nThey don't have to be hurricanes or typhoons per se, just large storms. I would think the low pressure regions of two storms would tend to attract each other if they were nearby, but it's apparently rare or unheard of because a quick google search showed nothing.","reasoning":"The post intends to figure out some merged hurricanes. The anwser is yes, and the phonomenon can be explained by  Fujiwhara effect.","id":"28","excluded_ids":["N\/A"],"gold_ids_long":["merged_hurricanes\/Hurricane_Diane.txt","merged_hurricanes\/Hurricane_Connie.txt","merged_hurricanes\/Fujiwhara_effect.txt"],"gold_ids":["merged_hurricanes\/Fujiwhara_effect2.txt","merged_hurricanes\/Fujiwhara_effect3.txt","merged_hurricanes\/Fujiwhara_effect1.txt","merged_hurricanes\/Hurricane_Connie1.txt","merged_hurricanes\/Hurricane_Diane2.txt","merged_hurricanes\/Hurricane_Connie5.txt","merged_hurricanes\/Hurricane_Connie6.txt","merged_hurricanes\/Hurricane_Connie4.txt","merged_hurricanes\/Hurricane_Connie2.txt","merged_hurricanes\/Hurricane_Diane4.txt","merged_hurricanes\/Hurricane_Diane1.txt","merged_hurricanes\/Hurricane_Connie3.txt","merged_hurricanes\/Hurricane_Diane3.txt","merged_hurricanes\/Hurricane_Diane5.txt"],"gold_answer":"$\\begingroup$\n\nYes two hurricanes\/tropical cyclones\/typhoons can merge with each other and\nthe effect is known as Fujiwhara effect- [ Fujiwhara effect\n](https:\/\/en.wikipedia.org\/wiki\/Fujiwhara_effect) .\n\nThe National Weather Service defines the Fujiwhara effect as \"Binary\nInteraction where tropical cyclones within a certain distance(300-375 nautical\nmiles depending on the size of the cyclones) of each other begin to rotate\nabout a common midpoint\". What really happens is that centers of both systems\nbegin to orbit in a counter clockwise direction about a midpoint that is\ndetermined by the relative mass and cyclone intensity. Eventually the smaller\ncyclone may merge into the larger cyclone. There are several examples of the\nFujiwhara effect and one example would be Hurricane Connie [ Hurricane Connie\n](https:\/\/en.wikipedia.org\/wiki\/Hurricane_Connie) and Diane [ Hurricane Diane\n](https:\/\/en.wikipedia.org\/wiki\/Hurricane_Diane) way back in 1955. Shimokawa\net al [ Fujiwhara Effect Types ](http:\/\/dil-\nopac.bosai.go.jp\/publication\/nied_natural_disaster\/pdf\/45\/45-02E.pdf) talk\nabout the various kinds of interactions that can take place among various\ntyphoons(Please note that the Fujiwhara effect is not restricted to two\nsystems). The various kinds of interactions are\n\n  * Complete Merger \n  * Partial Merger \n  * Complete Straining Out \n  * Partial Straining Out \n  * Elastic Straining Out \n\nComplete straining and complete merger interactions lead to destruction of one\nof the vortices. Partial merger and partial straining lead to partial\ndestruction of one vortex and elastic straining is an interaction in which\nboth vortices survive with their initial circulation. Partial merger and\npartial straining out have received less attention in the literature on binary\ntropical cyclone interactions as the interactions are extremely complex.\nPrieto et al claim that during a partial merger repeated mass exchanges occur\nbetween vortices. As these are nonlinear effects a quantification is only\npossible by a direct numerical integration and precise initial condition [\nBinary TC Vortex Like Interactions\n](http:\/\/journals.ametsoc.org\/doi\/pdf\/10.1175\/1520-0493%282003%29131%3C2656%3AACOBTC%3E2.0.CO%3B2)\n\nThe period of orbit maybe as small as one day or there are others such as\nCyclone Kathy and Cyclone Marie [ Kathy\/Marie Fujiwhara\n](https:\/\/en.wikipedia.org\/wiki\/1964_Pacific_typhoon_season#Typhoon_Marie_.28Undang.29)\norbited for a period of 5 days prior to merging into each other as pointed out\nby [ Lander et al\n](http:\/\/twister.ou.edu\/QJ\/CD3-1990-1995\/1993\/v119n514\/s5.pdf?origin=publication_detail)\n. If the period of orbit is longer then there is a greater probability of a\nmerger.\n\nRegion wise binary cyclones are more common in the Western North Pacific than\nthe North Atlantic as pointed by Dong et al [ Relative Motion Of Binary\nTropical Cyclones\n](http:\/\/journals.ametsoc.org\/doi\/pdf\/10.1175\/1520-0493%281983%29111%3C0945%3AOTRMOB%3E2.0.CO%3B2)\nRegarding the predictability of the track of binary cyclones Dong et al. state\nthat prediction of steering forces of a single tropical cyclone are replete\nwith numerical forecasting uncertainties and the problem is accentuated by the\npresence of another tropical cyclone in close proximity. Those who followed\nthe progress of Hurricane Sandy in late October 2012 (an instance of the\nFujiwhara effect but in this case a tropical cyclone merged with an extra\ntropical storm) will remember the ECMWF model correctly predicted the landfall\nlocation."}
{"query":"I've had an inconclusive chat about the Sveconorwegian belt of the Fennoscandian shield, the western parts in particular, and reasons as to why there would not be any deposits of hydrocarbons there. Perhaps someone here can provide a definite answer?\n\nIs it simply that the belt is of primarily Gothian origin, or might there be more to it?","reasoning":"This post wonders why there's no  hydrocarbons in the Sveconorwegian belt. There are mainly 3 reasons: 1. These old rocks never had a good source rock: too old, too little life. \r\n2. They are so old that any source would have been mature hundreds of millions of years ago.\r\n3. In any case, metamorphosis has destroyed any potential reservoirs, and a combination of tectonism, orogenesis, and exhumation has destroyed any traps.","id":"29","excluded_ids":["N\/A"],"gold_ids_long":["no_hydrocarbons_in_sveconorwegian_belt\/Petroleum_trap.txt","no_hydrocarbons_in_sveconorwegian_belt\/Kerogen.txt","no_hydrocarbons_in_sveconorwegian_belt\/Petroleum_reservoir.txt"],"gold_ids":["no_hydrocarbons_in_sveconorwegian_belt\/Petroleum_reservoir7.txt","no_hydrocarbons_in_sveconorwegian_belt\/Kerogen5.txt","no_hydrocarbons_in_sveconorwegian_belt\/Kerogen8.txt","no_hydrocarbons_in_sveconorwegian_belt\/Petroleum_reservoir2.txt","no_hydrocarbons_in_sveconorwegian_belt\/Petroleum_trap3.txt","no_hydrocarbons_in_sveconorwegian_belt\/Kerogen3.txt","no_hydrocarbons_in_sveconorwegian_belt\/Kerogen1.txt","no_hydrocarbons_in_sveconorwegian_belt\/Kerogen6.txt","no_hydrocarbons_in_sveconorwegian_belt\/Petroleum_reservoir3.txt","no_hydrocarbons_in_sveconorwegian_belt\/Petroleum_trap1.txt","no_hydrocarbons_in_sveconorwegian_belt\/Petroleum_reservoir1.txt","no_hydrocarbons_in_sveconorwegian_belt\/Petroleum_reservoir4.txt","no_hydrocarbons_in_sveconorwegian_belt\/Petroleum_trap4.txt","no_hydrocarbons_in_sveconorwegian_belt\/Kerogen2.txt","no_hydrocarbons_in_sveconorwegian_belt\/Kerogen9.txt","no_hydrocarbons_in_sveconorwegian_belt\/Kerogen4.txt","no_hydrocarbons_in_sveconorwegian_belt\/Petroleum_trap2.txt","no_hydrocarbons_in_sveconorwegian_belt\/Petroleum_reservoir8.txt","no_hydrocarbons_in_sveconorwegian_belt\/Kerogen7.txt","no_hydrocarbons_in_sveconorwegian_belt\/Petroleum_reservoir5.txt","no_hydrocarbons_in_sveconorwegian_belt\/Petroleum_reservoir6.txt"],"gold_answer":"$\\begingroup$\n\nThere's a little more to it than its substantial age, but not a lot.\n\nFirst, a bit of background. We need a few conditions for accumulations of oil\nor gas:\n\n  * A [ kerogen ](https:\/\/en.wikipedia.org\/wiki\/Kerogen) -rich source rock that has been 'cooked' to thermal maturity. Insufficient temperature, or insufficient time, and it's undercooked; if the temperature is too high, or the rock is very old, then the volatiles have all been discharged or cracked. I don't know of any source rocks older than about Ordovician; the best ones are Jurassic in age. \n  * A migration pathway from the source to a trapping configuration, and time for this to have happened. \n  * A [ structural ](https:\/\/en.wikipedia.org\/wiki\/Structural_trap) or stratigraphic trap, such as an anticline, and the geological conditions that have preserved it since filling. \n  * A reservoir rock \u2014 a porous and permeable rock. Usually this is a sedimentary rock, though hydrocarbons have been discovered in fractured granites (in Vietnam for example; this is rare). \n\nOnly 'conventional' hydrocarbon deposits need all these conditions (sometimes\ncalled a [ 'petroleum system' ](http:\/\/subsurfwiki.org\/wiki\/Petroleum_system)\n, such as you might find in the North Sea). 'Shale gas' is basically just a\nmature source rock \u2014 we can extract hydrocarbons from it by fracking, for\nexample.\n\nAs you might guess from the list of conditions, there are lots of things that\ncan destroy a hydrocarbon accumulation, or preclude its formation. For\nexample, deep burial destroys porosity by diagenesis and compaction. Time\nincreases the likelihood of trap leakage or thermal destruction of volatiles.\n\nSo, why no hydrocarbons in the (mostly Precambrian) Swedish-Norwegian shield?\nMaybe these are the top 3 reasons:\n\n  * These old rocks never had a good source rock: too old, too little life. A bad start. \n  * They are so old that any source would have been mature hundreds of millions of years ago. \n  * In any case, metamorphosis has destroyed any potential reservoirs, and a combination of tectonism, orogenesis, and exhumation has destroyed any traps."}
{"query":"I know that helium is a very light and rare gas on Earth because Earths gravity is not strong enough to keep it. Instead, helium and hydrogen are rising through the atmosphere and escape into outer space.\n\nMy question is: How massive would Earth have to be so that it could keep helium in the atmosphere? 2, 5, or 10 times the actual mass? Could we, for example, compare it to Neptune or Saturn?","reasoning":"The post wants to calculate the 'g' which guarantee helium on earth. It's actually a possiblity distribution. ","id":"30","excluded_ids":["N\/A"],"gold_ids_long":["g_needed\/Atmospheric_escape.txt","g_needed\/Atmospheric_escape#Thermal_escape_mechanisms.txt","g_needed\/Maxwell_E2_80_93Boltzmann_distribution.txt"],"gold_ids":["g_needed\/Maxwell_E2_80_93Boltzmann_distribution3.txt","g_needed\/Atmospheric_escape#Thermal_escape_mechanisms1.txt","g_needed\/Atmospheric_escape#Thermal_escape_mechanisms4.txt","g_needed\/Maxwell_E2_80_93Boltzmann_distribution5.txt","g_needed\/Atmospheric_escape1.txt","g_needed\/Maxwell_E2_80_93Boltzmann_distribution2.txt","g_needed\/Maxwell_E2_80_93Boltzmann_distribution7.txt","g_needed\/Maxwell_E2_80_93Boltzmann_distribution6.txt","g_needed\/Atmospheric_escape#Thermal_escape_mechanisms6.txt","g_needed\/Atmospheric_escape6.txt","g_needed\/Atmospheric_escape#Thermal_escape_mechanisms5.txt","g_needed\/Atmospheric_escape#Thermal_escape_mechanisms2.txt","g_needed\/Atmospheric_escape4.txt","g_needed\/Atmospheric_escape#Thermal_escape_mechanisms3.txt","g_needed\/Maxwell_E2_80_93Boltzmann_distribution4.txt","g_needed\/Atmospheric_escape5.txt","g_needed\/Atmospheric_escape2.txt","g_needed\/Atmospheric_escape3.txt"],"gold_answer":"$\\begingroup$\n\n[ Atmospheric escape ](https:\/\/en.wikipedia.org\/wiki\/Atmospheric_escape) is\nthe loss of planetary atmospheric gases to outer space. You'd never be able to\ncontain ALL of any gas forever by gravity. Ultimately you end up in the\nrarefied atmosphere where there is some probability that a molecule of gas\nwill reach escape velocity. The probability distribution is given by the [\nMaxwell-Boltzmann distribution\n](https:\/\/en.wikipedia.org\/wiki\/Maxwell%E2%80%93Boltzmann_distribution) and\nthe thermal escape mechanism is known as the [ Jeans escape\n](https:\/\/en.wikipedia.org\/wiki\/Atmospheric_escape#Thermal_escape_mechanisms)\n.\n\nOn earth the problem is compounded by the fact that helium is lighter that the\nother gases. So (1) helium migrates to the upper atmosphere because of its\ndensity and (2) helium atoms on average have the same kinetic energy as oxygen\nand nitrogen molecules which means that helium atoms are on average traveling\nmuch faster than oxygen or nitrogen molecules.\n\nAll of this is made more complicated by needing a temperature profile of the\natmosphere as a function of the height.\n\nIt doesn't help to assume temperature of background radiation because even at\nthat temperature you can calculate the probability of a helium atom having 80%\nof light speed. This sort of like being able to calculate the probability of\nthrowing $n$ heads in a row regardless of how big $n$ is."}
{"query":"The magnetic North (or South) Pole moves due to activities in the inner of Earth. And earthquakes can tilt the Earth's orientation a tiny bit. But can and does the axis' orientation relative to the surface change too? A major impact could surely do it, but could the Earth's inner activities?\n\nI don't mean precession, nor tectonics or continental drift, but the movement of the rotation axis. Could for example the geographic North Pole move to Greenland? (Not Greenland moving to the NP)","reasoning":"The post wonders whether the earth's geographic north point move. It's a phenomenon called polar motion.","id":"31","excluded_ids":["N\/A"],"gold_ids_long":["north_pole_rotation\/Polar_motion.txt"],"gold_ids":["north_pole_rotation\/Polar_motion1.txt","north_pole_rotation\/Polar_motion6.txt","north_pole_rotation\/Polar_motion2.txt","north_pole_rotation\/Polar_motion4.txt","north_pole_rotation\/Polar_motion5.txt","north_pole_rotation\/Polar_motion3.txt"],"gold_answer":"$\\begingroup$\n\n**Yes, it's called[ _polar motion_\n](https:\/\/en.wikipedia.org\/wiki\/Polar_motion) . **\n\nThe rotational pole moves continuously, as you can see from the right-hand\nside of this figure (below) by the [ Earth Orientation Centre\n](http:\/\/hpiers.obspm.fr\/eop-pc\/) (EOC) and the [ International Earth Rotation\nand Reference Systems Service\n](http:\/\/www.iers.org\/IERS\/EN\/Organization\/ProductCentres\/EarthOrientationCentre\/eoc.html)\n(IERS). The figure shows about 650 days of time; ` mjd ` is _modified Julian\nday_ and time goes along the locus in the polar motion diagram.\n\n[ ![The daily polar motion](https:\/\/i.sstatic.net\/lP4kg.png)\n](https:\/\/i.sstatic.net\/lP4kg.png)\n\nThe left-hand side of the figure shows Length of Day, and I think that's\nchiefly why they are making these refined polar measurements \u2014 to keep track\nof leap seconds, etc.\n\nIt's been established, by Fong et al. (19996), among others, that [\nearthquakes could change the earth's rotational axis\n](http:\/\/www.nasa.gov\/topics\/earth\/features\/japanquake\/earth20110314.html) ,\nby redistributing mass on a large scale. Their table 1 shows [the sort of\neffect that individual earthquakes theoretically have \u2014 _edited after comment\nfrom David Hammen_ ] on the length of day; $\\Psi$ is the excitation vector:\n\n[ ![Table 1 from Fong et al 1996](https:\/\/i.sstatic.net\/BsKx1.png)\n](https:\/\/i.sstatic.net\/BsKx1.png)\n\nThe EOC's website lists [ other geophysical excitations\n](http:\/\/hpiers.obspm.fr\/eop-pc\/index.php?index=excitation&lang=en) , among\nthem:\n\n  * Atmospheric angular momentum \n  * Oceanic angular momentum \n  * Hydrological excitation function \n  * Axial angular momentum of the core \n\n###  References\n\nChao, Benjamin Fong, Richard S. Gross, Yan-Ben Han (1996). Seismic excitation\nof the polar motion, 1977\u20131993. _Pure and Applied Geophysics_ , September\n1996, Volume 146, Issue 3, pp 407-419. [ DOI 10.1007\/BF00874727\n](http:\/\/dx.doi.org\/10.1007\/BF00874727)\n\n**Update:** [ This article ](http:\/\/www.nasa.gov\/feature\/nasa-study-solves-\ntwo-mysteries-about-wobbling-earth) on some new research in this field is\nworth a read."}
{"query":"I was checking the weather forecast just now, and it is showing that it \"feels like -999 \u00b0C\". I never heard or saw -999 \u00b0C before. I searched other weather channels, and they were showing that it feels like 2 \u00b0C. What is the meaning of -999 \u00b0C, irrespective of the weather?","reasoning":"The post wonders what the meaning of -999 celsius degree is. It doesn' t mean anything since the absolute zero is higher than it. ","id":"32","excluded_ids":["N\/A"],"gold_ids_long":["-999_celsius_degree\/Absolute_zero.txt","-999_celsius_degree\/Lowest_temperature_recorded_on_Earth.txt"],"gold_ids":["-999_celsius_degree\/Lowest_temperature_recorded_on_Earth1.txt","-999_celsius_degree\/Absolute_zero4.txt","-999_celsius_degree\/Absolute_zero1.txt","-999_celsius_degree\/Lowest_temperature_recorded_on_Earth3.txt","-999_celsius_degree\/Absolute_zero6.txt","-999_celsius_degree\/Absolute_zero3.txt","-999_celsius_degree\/Lowest_temperature_recorded_on_Earth2.txt","-999_celsius_degree\/Absolute_zero7.txt","-999_celsius_degree\/Absolute_zero5.txt","-999_celsius_degree\/Absolute_zero2.txt"],"gold_answer":"$\\begingroup$\n\nThe value -999 is likely the \"fill value\" used in the dataset when data is\nmissing or is not being properly filtered or handled when displayed. In the\nspecific case on the website you cite, it is likely a problem with the\nalgorithm for wind chill (the \"feels like\" temperature this time of year).\n\nIt isn't a physical value and only means the value is missing. Furthermore,\n-999\u00b0C is not a possible value because [ absolute zero\n](https:\/\/en.wikipedia.org\/wiki\/Absolute_zero) is \u2013273.15\u00b0C, and it's not\npossible to be colder than this (at least [ not in any meaningful way\n](http:\/\/www.nature.com\/news\/quantum-gas-goes-below-absolute-zero-1.12146) ,\nand certainly not because of wind chill). The [ coldest recorded temperature\n](https:\/\/en.wikipedia.org\/wiki\/Lowest_temperature_recorded_on_Earth) on earth\nis around \u201390\u00b0C."}
{"query":"between 1950 to 1980 there were negative temperature anomalies in the years of those decades.\n\ndecade        difference (\u00b0C)        difference (\u00b0F)\n1950\u20131959        \u22120.02        -0.0360\n1960\u20131969        \u22120.014        \u22120.0252\n1970\u20131979        \u22120.001        \u22120.0018\nThis seems odd considering massive oil consumption started in 1880 IIRC, and by 1980 over 350 billions of oil barrels were already consumed (much more probably, since the data before 1950 isn't considered because there weren't reliable records).\n\nWhy was there a negative temperature anomaly between 1950 to 1980?","reasoning":"The post observes that there's a negative temperature falling in the year of 1950-1980. It's a result of global dimming","id":"33","excluded_ids":["N\/A"],"gold_ids_long":["temperature_anomaly\/Global_dimming.txt"],"gold_ids":["temperature_anomaly\/Global_dimming4.txt","temperature_anomaly\/Global_dimming3.txt","temperature_anomaly\/Global_dimming2.txt","temperature_anomaly\/Global_dimming1.txt","temperature_anomaly\/Global_dimming7.txt","temperature_anomaly\/Global_dimming5.txt","temperature_anomaly\/Global_dimming6.txt"],"gold_answer":"$\\begingroup$\n\nThis phenomenon is known as [ global dimming\n](https:\/\/en.wikipedia.org\/wiki\/Global_dimming) .\n\nIt was due to the particles and aerosols mostly released by combustion of\nfossil fuels such as diesel. Those particles block the radiation from the sun,\nso they have a cooling effect. For some decades this effect counterbalanced\nthe warming effect of greenhouse gases, although it is no longer the case at a\nglobal scale (see for instance [ Wild et al. 2007\n](https:\/\/doi.org\/10.1029\/2006GL028031) ). Particles emission has been reduced\nthanks to better engines and new regulations, which stopped their masking\neffect on global warming. Which is a good thing since those particles have a\nserious impact on health."}
{"query":"We know that plates can subduct, causing one plate to be pushed into the core by another. As the plates move, the subduction continues, pushing one plate under the other.\n\nIf this process continues, logic says, the entire plate could be subducted under the other.\n\nHas this ever happened? How would we know?","reasoning":"The post tries to find out if there's an entire plate subducted before. The anwser is yes, such as Intermontane Plate","id":"34","excluded_ids":["N\/A"],"gold_ids_long":["subducted_plate\/Intermontane_Islands.txt","subducted_plate\/Intermontane_Plate.txt"],"gold_ids":["subducted_plate\/Intermontane_Islands1.txt","subducted_plate\/Intermontane_Plate2.txt","subducted_plate\/Intermontane_Plate1.txt"],"gold_answer":"$\\begingroup$\n\nExcellent question! Indeed, entire plates have subducted before.\n\nOne example is the Intermontane Plate ( [ Wikipedia\n](https:\/\/en.wikipedia.org\/wiki\/Intermontane_Plate) ). This plate sat west of\nNorth America around 195 million years ago. The plate contained a chain of\nvolcanic islands on its western edge (known as the [ Intermontane Islands\n](https:\/\/en.wikipedia.org\/wiki\/Intermontane_Islands) ). As the plate\nsubducted under the North American plate, that island chain stood too tall and\nmerged with the North American plate.\n\nAn illustration of the plate:  \n![enter image description here](https:\/\/i.sstatic.net\/m3oXq.png)  \nSource: [ Black Tusk, Wikimedia Commons\n](https:\/\/en.wikipedia.org\/wiki\/File:Intermontane_arc.png)\n\nThe entire Intermontane Plate was subducted under the North American plate.\nHowever, we are able to see the remnants of the plate in the volcanic islands\nit left behind.\n\nOnce this Intermontane Plate was subducted, the Insular Plate became the new\nsubduction zone.\n\nThis entire process was actually repeated with the Insular Plate, subducting\nthe entire plate, leaving behind yet another chain of volcanic islands that\nfused to the western coast of the North American Plate.\n\nThe Burke Museum has an excellent article that describes the subduction of\nboth the [ Intermontane Plate\n](http:\/\/www.burkemuseum.org\/static\/geo_history_wa\/The%20Omineca%20Episode.htm)\nand the [ Insular Plate\n](http:\/\/www.burkemuseum.org\/static\/geo_history_wa\/Coast%20Range%20Episode.htm)\n. Well worth the read."}
{"query":"I'm using ADXL345 accelerometer with Raspberry Pi to build a seismograph. I've successfully hooked it up and can plot the accelerometer data in three axis. Is there any way to express these data in the form of the magnitude of an earthquake, of course, at the point of sensing? I know that it might be imprecise, but any representation would be helpful (e.g. Richter scale), and how to accomplish that.","reasoning":"Using an accelrtometer as a seismograph is not possible, it can only be used to measure the local sesmic intensity. Instead, if we have two, it's possible as it can triangulate the location of the earthquake. ","id":"35","excluded_ids":["N\/A"],"gold_ids_long":["using_accelerometer_as_a_seismograph\/Seismic_intensity_scales.txt","using_accelerometer_as_a_seismograph\/Peak_ground_acceleration.txt","using_accelerometer_as_a_seismograph\/Richter_scale.txt"],"gold_ids":["using_accelerometer_as_a_seismograph\/Seismic_intensity_scales7.txt","using_accelerometer_as_a_seismograph\/Seismic_intensity_scales1.txt","using_accelerometer_as_a_seismograph\/Peak_ground_acceleration5.txt","using_accelerometer_as_a_seismograph\/Peak_ground_acceleration3.txt","using_accelerometer_as_a_seismograph\/Peak_ground_acceleration2.txt","using_accelerometer_as_a_seismograph\/Seismic_intensity_scales5.txt","using_accelerometer_as_a_seismograph\/Peak_ground_acceleration4.txt","using_accelerometer_as_a_seismograph\/Richter_scale7.txt","using_accelerometer_as_a_seismograph\/Richter_scale5.txt","using_accelerometer_as_a_seismograph\/Seismic_intensity_scales2.txt","using_accelerometer_as_a_seismograph\/Peak_ground_acceleration1.txt","using_accelerometer_as_a_seismograph\/Seismic_intensity_scales3.txt","using_accelerometer_as_a_seismograph\/Richter_scale2.txt","using_accelerometer_as_a_seismograph\/Richter_scale3.txt","using_accelerometer_as_a_seismograph\/Richter_scale1.txt","using_accelerometer_as_a_seismograph\/Richter_scale4.txt"],"gold_answer":"$\\begingroup$\n\nThe magnitude of an earthquake is related to the total energy released,\ntherefore to estimate it from a seismogram you need to know the distance to\nthe source. In the case of the [ Richter scale\n](https:\/\/en.wikipedia.org\/wiki\/Richter_magnitude_scale) for example, the\nrelationship between magnitude and seismogram amplitude is defined for a\nstandard distance.\n\nIf you have only one seismograph, you can not triangulate the location of the\nsource ( [ hypocenter ](https:\/\/en.wikipedia.org\/wiki\/Hypocenter) ).\nTherefore, you can not estimate the magnitude of a seismic event (Richter or [\nmoment magnitude ](https:\/\/en.wikipedia.org\/wiki\/Moment_magnitude_scale) ).\n\n**But you can estimate the[ local seismic intensity\n](https:\/\/en.wikipedia.org\/wiki\/Seismic_intensity_scales) of the event ** at\nthe particular location of your instrument. With the accelerometer data you\ncan easily measure the [ peak ground acceleration\n](https:\/\/en.wikipedia.org\/wiki\/Peak_ground_acceleration) , that can be used\nto estimate the intensity in any of the [ existing scales\n](https:\/\/en.wikipedia.org\/wiki\/Seismic_intensity_scales) . For example, the\npeak ground accelerations associated to each intensity level in the commonly\nused [ Mercalli intensity scale\n](https:\/\/en.wikipedia.org\/wiki\/Mercalli_intensity_scale) are:\n\n[ ![table of intensities](https:\/\/i.sstatic.net\/F6aGo.png)\n](https:\/\/i.sstatic.net\/F6aGo.png)\n\nThose _g_ values would be easy to calculate with the accelerometer data and\nproper calibration constants.\n\n_Table taken from the Wikipedia page for[ peak ground acceleration\n](https:\/\/en.wikipedia.org\/wiki\/Peak_ground_acceleration) _\n\nYou might want to have a look at [ this question\n](https:\/\/earthscience.stackexchange.com\/questions\/4681\/characterizing-\nearthquakes-using-accelerometer-data) . There are some nice answers and\nreferences that you might find useful."}
{"query":"What is the scientific reason for the majestic sights of the northern and southern lights, otherwise known as Auroras near the magnetic poles, and why do the northern lights differ from the southern lights?","reasoning":"Cause of auroras: Auroras are colorful displays in the upper atmosphere caused by collisions between charged particles from the solar wind and atmospheric gases like oxygen and nitrogen. The colors (green, red, blue) depend on the atmospheric gas, altitude, and energy levels involved in the collisions. Auroras are more intense during peak solar activity when the solar wind is stronger.\n","id":"36","excluded_ids":["N\/A"],"gold_ids_long":["aurora\/Aurora.txt"],"gold_ids":["aurora\/Aurora1.txt","aurora\/Aurora2.txt"],"gold_answer":"$\\begingroup$\n\nStraight from [ wikipedia\n](https:\/\/en.wikipedia.org\/wiki\/Aurora#Auroral_mechanism) :\n\n> Auroras are associated with the solar wind, a flow of ions continuously\n> flowing outward from the Sun. The Earth's magnetic field traps these\n> particles, many of which travel toward the poles where they are accelerated\n> toward Earth. Collisions between these ions and atmospheric atoms and\n> molecules cause energy releases in the form of auroras appearing in large\n> circles around the poles. Auroras are more frequent and brighter during the\n> intense phase of the solar cycle when coronal mass ejections increase the\n> intensity of the solar wind.\n>\n> Auroras result from emissions of photons in the Earth's upper atmosphere,\n> above 80 km (50 mi), from ionized nitrogen molecules regaining an electron,\n> and oxygen atoms and nitrogen molecules returning from an excited state to\n> ground state. They are ionized or excited by the collision of solar wind and\n> magnetospheric particles being funneled down and accelerated along the\n> Earth's magnetic field lines; excitation energy is lost by the emission of a\n> photon, or by collision with another atom or molecule:\n>\n>   * **oxygen emissions** : green or brownish-red, depending on the amount of\n> energy absorbed.\n>\n>   * **nitrogen emissions** : blue or red; blue if the atom regains an\n> electron after it has been ionized, red if returning to ground state from an\n> excited state.\n>\n>\n\n>\n> Oxygen is unusual in terms of its return to ground state: it can take three\n> quarters of a second to emit green light and up to two minutes to emit red.\n> Collisions with other atoms or molecules absorb the excitation energy and\n> prevent emission. Because the very top of the atmosphere has a higher\n> percentage of oxygen and is sparsely distributed such collisions are rare\n> enough to allow time for oxygen to emit red. Collisions become more frequent\n> progressing down into the atmosphere, so that red emissions do not have time\n> to happen, and eventually even green light emissions are prevented.\n>\n> This is why there is a color differential with altitude; at high altitude\n> oxygen red dominates, then oxygen green and nitrogen blue\/red, then finally\n> nitrogen blue\/red when collisions prevent oxygen from emitting anything.\n> Green is the most common of all auroras. Behind it is pink, a mixture of\n> light green and red, followed by pure red, yellow (a mixture of red and\n> green), and finally, pure blue."}
{"query":"When thinking about the formation of the current continents from a super-continent, it's clear that this is a gradual process, but there must be certain areas on earth which were once joined and were the \"last\" to break apart from Pangea.\n\nDo we know when and where these rifting \/ break-up events took place?","reasoning":"There's no way to predict when and where a continent can rift, it's not on the human's time scale.","id":"37","excluded_ids":["N\/A"],"gold_ids_long":["rifting\/Madagascar_Plate.txt","rifting\/Rio_Grande_rift.txt","rifting\/East_African_Rift.txt","rifting\/Rift.txt"],"gold_ids":["rifting\/Rift1.txt","rifting\/Madagascar_Plate1.txt","rifting\/East_African_Rift2.txt","rifting\/East_African_Rift3.txt","rifting\/East_African_Rift6.txt","rifting\/Rio_Grande_rift3.txt","rifting\/East_African_Rift1.txt","rifting\/East_African_Rift5.txt","rifting\/Rift4.txt","rifting\/Madagascar_Plate3.txt","rifting\/East_African_Rift8.txt","rifting\/East_African_Rift4.txt","rifting\/Madagascar_Plate2.txt","rifting\/East_African_Rift7.txt","rifting\/Rio_Grande_rift1.txt","rifting\/Rio_Grande_rift2.txt","rifting\/Rift5.txt","rifting\/Rift3.txt","rifting\/Rift2.txt"],"gold_answer":"$\\begingroup$\n\n[ Rifting ](https:\/\/en.wikipedia.org\/wiki\/Rift) is an ongoing process. At the\nmoment, e.g. East Africa is [ rifting\n](https:\/\/en.wikipedia.org\/wiki\/East_African_Rift) apart from the Nubian\nplate, we also see rifting of continental plates elsewhere, eg [ Rio Grande\n](https:\/\/en.wikipedia.org\/wiki\/Rio_Grande_rift) . New continents are being\nformed, but it doesn't happen on a human time scale. Modellers of [ future\ngeography ](http:\/\/www.livescience.com\/18387-future-earth-supercontinent-\namasia.html) have a [ difficult task\n](http:\/\/www.sciencearchive.org.au\/nova\/newscientist\/104ns_011.htm) to decide\nwhat rifts that will stop and what rift that eventually will result in a new\ncontinent.\n\nSee yellow marked faults and rifts: ![enter image description\nhere](https:\/\/i.sstatic.net\/Y22u1.gif)\n\n[ Madagascar ](https:\/\/en.wikipedia.org\/wiki\/Madagascar_Plate) is sometimes\nrefereed to as the _eight continent_ , not only of biogeographic reasons. It\nwas rifting away from Africa and later India during mesozoic time, [ starting\n160 Ma\n](http:\/\/www.researchgate.net\/publication\/248564376_The_Great_Rift_Valley_of_Madagascar_An_extension_of_the_AfricaSomali_diffusive_plate_boundary)\n.\n\nThe last rifting that resulted in the present continents I can think about\n(probably the community can come up with a later event!), would be the North\nAtlantic breakup, that is still ongoing, but the last part of separation of\npresent continents was the [ opening\n](http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0040195108000024#) of the\n[ Fram Strait ](https:\/\/en.wikipedia.org\/wiki\/Fram_Strait) [ 16-10 Ma\n](http:\/\/epic.awi.de\/16218\/) . This separated Greenland from the European\nplate and had a [ large impact\n](http:\/\/www.sciencedaily.com\/releases\/2011\/01\/110127141659.htm) on the Arctic\nOcean conditions."}
{"query":"What causes the different colours of the salts pits in the Saloum Delta in Senegal?","reasoning":"The reason behind the colorful salt pits is variable algal concentrations. As the salinity of the pond increases, Micro-organisms change their hues. ","id":"38","excluded_ids":["N\/A"],"gold_ids_long":["salt_pits\/Exercise_Ions_&_Solutions_Salt_Farming.txt"],"gold_ids":["salt_pits\/Exercise_Ions_&_Solutions_Salt_Farming2.txt"],"gold_answer":"$\\begingroup$\n\nWriting about the San Francisco Bay salt ponds, [ Dr R. J. Rusay notes\n](http:\/\/chemconnections.org\/general\/chem120\/solutions-mixes.html) :\n\n> Due to variable algal concentrations, vivid colors, from pale green to\n> bright red are created. The color indicates the salinity of the ponds.\n> Micro-organisms change their hues as the salinity of the pond increases. In\n> low to mid-salinity ponds, green algae are predominant. In middle to high\n> salinity ponds, an algae called Dunaliella salina shifts the color to red.\n> Millions of tiny brine shrimp create an orange cast in mid-salinity ponds.\n> Other bacteria such as Stichococcus also contribute tints.\n\nRusay says nothing about the Saloum Delta, but the explanation could be\nsimilar there."}
{"query":"Methane clathrates are\n\nsolid clathrate compound (more specifically, a clathrate hydrate) in which a large amount of methane is trapped within a crystal structure of water, forming a solid similar to ice.\n\nThey mostly are on the bottom of the world's oceans; however, the overly brief wikipedia section for continental deposits suggests that it also occurs in Siberia, northern Canada and Alaska.\n\nHow much methane clathrates are believed to be buried in these continental deposits?","reasoning":"The question just asks about the mass of methane clathrates are buried in continental deposit. ","id":"39","excluded_ids":["N\/A"],"gold_ids_long":["methane_clathrates\/BF00144504.txt"],"gold_ids":["methane_clathrates\/BF001445042.txt","methane_clathrates\/BF001445043.txt"],"gold_answer":"$\\begingroup$\n\nAccording to [ Role of methane clathrates in past and future climates\n](http:\/\/link.springer.com\/article\/10.1007%2FBF00144504) ,\n\n> Methane occurrences and the organic carbon content of sediments are the\n> bases used to estimate the amount of carbon currently stored as clathrates.\n> The estimate of about 11,000 Gt of carbon for ocean sediments, and about 400\n> Gt for sediments under permafrost regions...\n\nSo 400 billion tons."}
{"query":"Supervolcanos have occurred in the recent geological past, but not within the past 74,000 years. Is it possible to find the magma chambers with no previous history of supervolcanic activity that are likely to produce supervolcanos?","reasoning":"To find the magma chambers which produces super volcanals, use the method of seismic tomography. ","id":"40","excluded_ids":["N\/A"],"gold_ids_long":["magma_chambers\/Seismic_tomography.txt"],"gold_ids":["magma_chambers\/Seismic_tomography4.txt","magma_chambers\/Seismic_tomography5.txt"],"gold_answer":"$\\begingroup$\n\nI am a seismologist, not a volcanologist, but we can use a method called\nseismic tomography to understand the size of magma chambers.\n\nThis method is similar to a medical CT scan - the magma mush will have a\nslower seismic wavespeed than the surrounding 'normal' rock. Therefore, we can\nuse this to determine the size of magma chambers from a tomographic image.\n\nEven if a volcano does not appear to be active at the surface, it could still\noverlie a magmatic anomaly.\n\nThis approach was recently used to estimate the seismic of the Yellowstone\nmagmatic body. See this paper: [\nhttp:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/2014GL059588\/abstract\n](http:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/2014GL059588\/abstract)\n\nSeismic tomography can theoretically be applied to any region, but we just\nneed to have enough seismic sources nearby (e.g. earthquakes) to be able to do\nthis accurately."}
{"query":"Popular news has several articles linking back to the news article in Nature Earth\u2019s magnetic field is acting up and geologists don\u2019t know why which discusses the need for an early update to the World Geomagnetic Model.\n\nHowever my question is about one line found in the Independent's Planet\u2019s erratic magnetic field forces emergency update to global navigation system\n\nThe shift they observed was so large it was on the verge of exceeding the acceptable limit for navigation errors.\n\nTo account for this, scientists at the British Geological Survey and the US National Oceanic and Atmospheric Administration (NOAA) are issuing an unprecedented emergency update to the model.\n\nThey have fed in the latest data, including an unexpected geomagnetic pulse that took place beneath South America in 2016, to ensure the system is more accurate.\n\nQuestion: What is the nature, and underlying cause of the \"unexpected geomagnetic pulse that took place beneath South America in 2016\"?\n\nAKA geomagnetic jerk.","reasoning":"the cause of the geomagnatic pulse is the magnetic field change. ","id":"41","excluded_ids":["N\/A"],"gold_ids_long":["geomagnetic_pulse\/Geomagnetic_jerk.txt","geomagnetic_pulse\/2013JB010604.txt"],"gold_ids":["geomagnetic_pulse\/Geomagnetic_jerk5.txt","geomagnetic_pulse\/Geomagnetic_jerk1.txt"],"gold_answer":"$\\begingroup$\n\nThe \"geomagnetic pulse\" here refers to a series of academic works studying the\nEarth's core such as [ this open access article\n](https:\/\/agupubs.onlinelibrary.wiley.com\/doi\/epdf\/10.1002\/2013JB010604)\n(other related articles require scientific journal subscriptions to read).\n\nGeomagnetic pulses have been associated with [ \"geomagnetic jerks\"\n](https:\/\/en.wikipedia.org\/wiki\/Geomagnetic_jerk) . [ A jerk was reported (yay\nfor open access again) to have occurred in 2014\n](https:\/\/agupubs.onlinelibrary.wiley.com\/doi\/epdf\/10.1002\/2015GL065501) , the\n2016 pulse under South America is believed to be related to this, both events\nhaving been measured and identified after the fact.\n\nThe magnetic field is always changing - a \"pulse\" is a quicker-than-normal\n(few year) acceleration of magnetic field change in time, in a region at the\nsurface of the Earth's outer core (magnetic field is generated within the\ncore).\n\nA \"jerk\" is a quick change (few months) of the rate at which magnetic field\nchanges at Earth's surface, making something like a 'V' shape if you plot the\nfield against time at a given location.\n\nThe idea is that a pulse occurs at the core, and jerks are an effect seen at\nthe surface just before and after the peak of the pulse, as the field change\nramps up and down. _The underlying cause of this is not known_ , and we only\nidentify them after they've occurred, so they're currently unpredictable. That\nsaid this behaviour is apparently part of the core's repertoire, and pulses\nand jerks have been observed before."}
{"query":"What parts of the fossil record are most lacking in specimens? That is, if you were to trace the evolution of a modern mammal (humans, for example) from abiogenesis to now, which periods are the most lacking in fossils? Where are the biggest gaps in our evolutionary history.","reasoning":"The time period Precambrian, specifically pre-Ediacarian, is most lacking of specimans. ","id":"42","excluded_ids":["N\/A"],"gold_ids_long":["lacking_fossil\/rstb_2006_1834.txt","lacking_fossil\/361219a0.txt"],"gold_ids":["lacking_fossil\/361219a02.txt"],"gold_answer":"$\\begingroup$\n\nThe biggest temporal gap would be (IMO) the Precambrian, specifically pre-\nEdiacarian. Accordingly the biggest gap in the evolutionary history is the\norigin of eukaryots, both because of the paucity of pre-Ediacarian formations\nbut also because few of the early protists were likely to be fossilizable.\n\nFrom the probable apparition of life ca. 3.8-3.5 Ga (e. g. **1** for a review\nof Archean fossils) to the Ediacarian (ca. 600 Ma) in which metazoans (i. e.\n\"animals\") are already diverse (e. g. **2** ), this is more than 3 Ga of life\nhistory for which we have very little fossils (though our knowledge of this\nfossil record increases currently thanks, in part, to our better understanding\nof the \"chemical\" fossil record).\n\n**1** : J. W. Schopf, 2006. [ Fossil evidence of Archaean life.\n](http:\/\/rstb.royalsocietypublishing.org\/content\/361\/1470\/869) Philosophical\ntransactions of the Royal Society, B., 361: 869-885.  \n**2** : S.Conway Morris, 1993. [ The fossil record and the early evolution of\nthe Metazoa\n](http:\/\/www.nature.com\/nature\/journal\/v361\/n6409\/abs\/361219a0.html) . Nature,\n361: 219-225."}
{"query":"Okay, so I believe that most of the impact\/collisions happen at oblique angles to the planet's radial direction. (I am not very sure about this, but since it is not a freefall, we can assume that the collision is oblique).\n\nSo why are most of the craters radially symmetric?\n\nWhy isn't the depression skewed?\n\nI have almost never come across a photograph of a skewed crater.","reasoning":"The post wants to find out why the impact craters are symmetric. It's due to the explosion when happening. ","id":"43","excluded_ids":["N\/A"],"gold_ids_long":["symmetric_crater\/Impact_crater.txt"],"gold_ids":["symmetric_crater\/Impact_crater4.txt","symmetric_crater\/Impact_crater3.txt"],"gold_answer":"$\\begingroup$\n\nThe main reason why impact craters are close to symmetrically round is because\nit's the explosion of the impactor, not its collision, that creates the impact\ncrater. The impactor is travelling so fast that, rather than simply exploding\non impact, it burrows deep into the collision site, heats up from compression\nand friction, and explodes deep underground, thus creating a more-or-less\nperfectly round crater."}
{"query":"I thought Auroras are only visible in the North Pole and South Pole, but recently, I found out that Auroras can be seen in areas of the world closer to the equator.\n\nAn example is that in the year 1909, a great storm of Auroras were seen in Japan and other countries.\n\nThis made me wonder: could an Aurora be seen in equatorial regions, too?","reasoning":"The post wants to check if it's possible to see auroras in the equator. The anwser says that it's possible theoratically, but very little chance. ","id":"44","excluded_ids":["N\/A"],"gold_ids_long":["aurora_equator\/Carrington_Event.txt"],"gold_ids":["aurora_equator\/Carrington_Event3.txt","aurora_equator\/Carrington_Event4.txt"],"gold_answer":"$\\begingroup$\n\nQuoting from the Wikipedia article on the [ Solar Storm of 1859\n](http:\/\/en.wikipedia.org\/wiki\/Solar_storm_of_1859) ;\n\n> On September 1\u20132, 1859, the largest recorded geomagnetic storm occurred.\n> Aurorae were seen around the world, those in the northern hemisphere even as\n> far south as the Caribbean; those over the Rocky Mountains were so bright\n> that their glow awoke gold miners, who began preparing breakfast because\n> they thought it was morning.[2] People who happened to be awake in the\n> northeastern US could read a newspaper by the aurora's light.[4] The aurora\n> was visible as far from the poles as Cuba and Hawaii.\n\nSo, it didn't quite make it to the equator, but it came very close. There is\nno physical reason why you can't get aurora at the equator, but it takes a lot\nof very energetic particles being ejected by the sun over a brief period.\n\nHowever, as I mentioned in my comment, a solar storm of that magnitude would\nwipe out most of the Earth's electric grids. Even the telegraph systems of the\n1800's couldn't survive. Another quote from the Wikipedia article;\n\n> Telegraph systems all over Europe and North America failed, in some cases\n> giving telegraph operators electric shocks.[6] Telegraph pylons threw\n> sparks.[7] Some telegraph systems continued to send and receive messages\n> despite having been disconnected from their power supplies.[8]"}
{"query":"The Yellowstone National Park in Wyoming is unique for its large number of \"thermal occurrences, of which there are some 30 geysers. This, in turn, appears to be the result of the presence of large quantities of molten rock, and the thinness of the earth's crust there, compared to the other spots on the earth.\n\nTo the best of my knowledge, there is no other (known) place on earth where so much thermal power is contained in a relatively small area. Is this in fact the case? If so, what made Yellowstone, Wyoming so unique in this regard?","reasoning":"The post wonders if the yellowstone park is unique for geysers. Actually it's famous for being build above a mantle plume","id":"45","excluded_ids":["N\/A"],"gold_ids_long":["yellow_stone\/Mantle_plume.txt","yellow_stone\/The_Yellowstone_Hotspot_Plume_or_Not.txt"],"gold_ids":["yellow_stone\/Mantle_plume4.txt","yellow_stone\/The_Yellowstone_Hotspot_Plume_or_Not5.txt","yellow_stone\/The_Yellowstone_Hotspot_Plume_or_Not4.txt","yellow_stone\/The_Yellowstone_Hotspot_Plume_or_Not2.txt","yellow_stone\/The_Yellowstone_Hotspot_Plume_or_Not1.txt","yellow_stone\/The_Yellowstone_Hotspot_Plume_or_Not3.txt"],"gold_answer":"$\\begingroup$\n\nYellowstone is thought to be above a [ mantle plume\n](http:\/\/en.wikipedia.org\/wiki\/Mantle_plume) , of with there are tens to\nhundreds on our planet, although there is plenty of [ debate on this matter\n](http:\/\/geology.gsapubs.org\/content\/40\/5\/479.full) . The exact nature of\nmantle plumes is a huge area of hotly contested research, but generally the\nare thought to be large melts originally sourced from the D'' layer (core \/\nmantle boundary). Below the park, the plume is theorized to have resulted in\nmagmatic intrusions overlain by a hydrothermal system. The intrusions can also\nbe considered as magma chambers of a supervolcano, which has had several\nultraplinean caldera-forming events.\n\nThe Yellowstone hotspot is the only obvious expression of a mantle plume\nbeneath the continental United States, which may be why you consider it\n\"unique.\" The other major plume \/ hotspot in the US is Hawaii.\n\nYellowstone is certainly not the only major geothermal area in the world;\ngeothermal areas in New Zealand, Italy, Japan and Antarctica are comparable in\nterms of heat flow. It's unclear what you mean by \"thermal power\" but\nYellowstone park does not have any geothermal electric power generation\nplants. New Zealand, on the other hand, generates 13% of their national power\nneeds geothermally."}
{"query":"In an area of frequent thunderstorms, I notice a 'crack or whoosh' sound if a strike is nearby but little or no thunder. Yet I can hear for 30 seconds or so after a distant flash when the thunder first is heard, the sound starts at a high frequency and then evolves into a deep rumble that can shake the walls. It approaches the sub-sonic. What is the relationship between the distance and the energy of the strike?","reasoning":"The thunder origin's varying distances from the observer can generate a rolling or rumbling effect. ","id":"46","excluded_ids":["N\/A"],"gold_ids_long":["propagation_of_sound_after_lightning\/Lightning.txt","propagation_of_sound_after_lightning\/what_causes_thunder_htm.txt"],"gold_ids":["propagation_of_sound_after_lightning\/what_causes_thunder_htm2.txt","propagation_of_sound_after_lightning\/Lightning3.txt","propagation_of_sound_after_lightning\/Lightning4.txt"],"gold_answer":"$\\begingroup$\n\nSince the sound waves propagate not from a single point source but along the\nlength of the lightning's path, the sound origin's varying distances from the\nobserver can generate a rolling or rumbling effect. Perception of the sonic\ncharacteristics is further complicated by factors such as the irregular and\npossibly branching geometry of the lightning channel, by acoustic echoing from\nterrain, and by the typically multiple-stroke characteristic of the lightning\nstrike.\n\nIn addition, thunder will sound louder when the air near the ground is colder\nand the air higher in the atmosphere is warmer. This is because the acoustic\nshock waves get \"trapped\" in the cold air. Such a temperature difference,\ncalled an inversion, tends to happen at night, which is why thunder often\nsounds louder at night.\n\nSee [ Wikipedia ](http:\/\/en.wikipedia.org\/wiki\/Lightning#Thunder) and [\nwisegeek.org ](http:\/\/www.wisegeek.org\/what-causes-thunder.htm)"}
{"query":"I am working on a data visualisation of airline flight paths and their probability of forming contrails.\n\nGiven weather data for a specific area (location, time, temperature, pressure and humidity) and aircraft data (location, time, altitude, speed and engine efficiency)\n\nIs there an equation that will give me a rough estimate of the probability contrails will form at this point?","reasoning":"Schmidt-Appleman criterion (SAC) is used to model contrail formation, which gives a rough estimate of the probability contrails","id":"47","excluded_ids":["N\/A"],"gold_ids_long":["contrial_formation\/gmd.txt"],"gold_ids":["contrial_formation\/gmd1.txt","contrial_formation\/gmd2.txt","contrial_formation\/gmd3.txt","contrial_formation\/gmd4.txt","contrial_formation\/gmd5.txt"],"gold_answer":"$\\begingroup$\n\nSchmidt-Appleman criterion (SAC) is used to model contrail formation. I advise\nreading in full Ulrich Schumann's article \"A contrail cirrus prediction model\"\n( [ http:\/\/www.geosci-model-dev.net\/5\/543\/2012\/gmd-5-543-2012.pdf\n](http:\/\/www.geosci-model-dev.net\/5\/543\/2012\/gmd-5-543-2012.pdf) ) to get all\nthe relevant formulae and literature references.\n\nWhile it is possible to transcribe the formulae here, the reference cited does\na better job of presenting state of the art (2012)."}
{"query":"The Wikipedia article on the subject of the \"Antarctic ice sheet\" says that:\n\nThe icing of Antarctica began in the middle Eocene about 45.5 million years ago and escalated during the Eocene\u2013Oligocene extinction event about 34 million years ago.\n\nThe article later says that:\n\nIce enters the sheet through precipitation as snow. This snow is then compacted to form glacier ice which moves under gravity towards the coast.\n\nHowever it looks like, from the photos of Antarctica, that this transfer of ice to the coasts is not happening everywhere on Antarctica. Rather, many places seem to be under a perpetual ancient ice cover.\n\nIf the precipitation was recycled at a continuous rate everywhere, it shouldn't be possible to obtain a 1.5 million year old core sample (according to an article in Nature) or structures such as Vostok Station that covers an ancient lake.\n\nA similar location is Dome F that according to Wikipedia has a yearly precipitation of about 25 mm (millimeters; approx. 0.98 inches).\n\nSo the question is, if we have a 25 mm precipitation per year for even just 10 million years, we should have an ice cover that's 250 kilometers thick. Or if we had it during just a 5 million year time span, it should give us an ice cover that's 125 kilometers thick.\n\nReasonably we could allow for some compression of the ice but still keeping in mind that we are not talking about a neutron star here.\n\nHow come the current Antarctic ice cover is just a couple of miles thick?","reasoning":"The author wonders what determines the thinkness of ice cover. It's based on  accumulation, ablation and compaction.","id":"48","excluded_ids":["N\/A"],"gold_ids_long":["ice_cover\/Ablation_zone.txt","ice_cover\/Accumulation_zone.txt"],"gold_ids":["ice_cover\/Ablation_zone4.txt","ice_cover\/Accumulation_zone4.txt"],"gold_answer":"$\\begingroup$\n\nIce floats with gravity towards lower elevation, the flow continues until the\nbase of the ice sheet becomes floating and the ice forms an ice shelf or\nicebergs.\n\nDue to the subglacial topography, basal melting and mass balance, the flow\nvelocities vary over a large range, faster outflows are glaciers. The pattern\nis somehow similar to how rivers transport rainwater towards the coasts.\n\nThe thickness of the ice sheet is controlled by a complex relation between [\naccumulation ](https:\/\/en.wikipedia.org\/wiki\/Accumulation_zone) , [ ablation\n](https:\/\/en.wikipedia.org\/wiki\/Ablation_zone) and compaction.\n\n[ ![Flow velocities MEaSUREs, plotted from\nQuantarctica](https:\/\/i.sstatic.net\/mC9rd.jpg)\n](https:\/\/i.sstatic.net\/mC9rd.jpg) _Flow velocities from[ MEaSUREs\n](https:\/\/nsidc.org\/data\/docs\/measures\/nsidc0484_rignot\/) (NASA), plotted from\n[ Quantarctica ](http:\/\/quantarctica.npolar.no\/) _\n\nThe ice velocity map shows, that some areas are unaffected by the flow towards\nthe coast. Some of these areas are ice-free. Also at some inland locations, as\nVostok, the velocity is very slow. Also, note that this is the surface\nvelocity. At the base, the ice flows slower or not at all.\n\nTo investigate the mass balance further, I recommended you to download [\nQuantarctica ](http:\/\/quantarctica.npolar.no\/) and look closer at the\ndatasets. [ Shepherd et al (2012)\n](https:\/\/ntrs.nasa.gov\/archive\/nasa\/casi.ntrs.nasa.gov\/20140006608.pdf) is a\ngood first read about the methods used to estimate changes in ice mass and the\npresent changes."}
{"query":"The line on the ground at the Greenwich Observatory is itself on a tectonic plate that is moving, so is the prime meridian still 0 degrees, 0 minutes, 0 seconds?\n\nIf not - what are the implications (if any)? For example, if my GPS says I am 100 km west of Greenwich Observatory, am I 100 km west of 0 0 0 or 100 km west of the line on the ground? Who (and what) decides this kind of thing?\n\nCurious punter, not a scientist....","reasoning":"The author wonders if the prime meridian moves as the land it on is moving. Answer is yes.","id":"49","excluded_ids":["N\/A"],"gold_ids_long":["prime_meridian\/s00190_015_0844_y.txt"],"gold_ids":["prime_meridian\/s00190_015_0844_y4.txt"],"gold_answer":"$\\begingroup$\n\nRemember it is just an imaginary line on the Earth's surface used for\ngeoreferencing purposes, so movement of the reference line has no implications\nso long as we can still reference to it (hence the International Reference\nMeridian).\n\nIn fact, the position of the Greenwich meridian has changed throughout\nhistory, mainly due to the Airy Transit Observatory (the original location of\nthe Greenwich meridian) being built next door to the previous one (to maintain\nthe service to shipping). Such changes had no significant practical effect.\nHistorically, the average error in the determination of longitude was much\nlarger than the change in position. The adoption of WGS84 (\"World Geodetic\nSystem 84\") as the positioning system has moved the geodetic prime meridian\n102.478 metres east of its last astronomic position (measured at Greenwich).\nThe position of the current geodetic prime meridian is not identified at all\nby any kind of sign or marking (as the older astronomic position was) in\nGreenwich, but can be located using a GPS receiver. Due to the movement of\nEarth's tectonic plates, the line of 0\u00b0 longitude along the surface of the\nEarth has slowly moved toward the west from this shifted position by a few\ncentimetres; that is, towards the Airy Transit Observatory (or the Airy\nTransit Observatory has moved toward the east, depending on your point of\nview) since 1984 (or the 1960s). With the introduction of satellite\ntechnology, it became possible to create a more accurate and detailed global\nmap. With these advances there also arose the necessity to define a reference\nmeridian that, whilst being derived from the Airy Transit Circle, would also\ntake into account the effects of plate movement and variations in the way that\nthe Earth was spinning - the International Reference Meridian.\n\nSee:\n\nMalys, S., Seago, J.H., Pavlis, N.K. et al. (2015) \"Why the Greenwich meridian\nmoved\" Journal of Geodesy. 89 (12) pp 1263\u20131272\n\nDolan, G (2013). \"WGS84 and the Greenwich Meridian\". The Greenwich Meridian."}
{"query":"Why are tropical cyclones in the Bay of Bengal more frequent and stronger than those in the Arabian Sea?","reasoning":"a low level jet covers the Arabian Sea during the indian sunner moonson, which cause tropical cycolones at the north india.","id":"50","excluded_ids":["N\/A"],"gold_ids_long":["india_cyclone\/nature10552_ref1.txt"],"gold_ids":["india_cyclone\/nature10552_ref12.txt"],"gold_answer":"$\\begingroup$\n\nDuring the Indian Summer Monsoon, a low level jet covers the Arabian Sea. This\ncauses vertical wind shear to increase over the Arabian Sea and inhibits\ncyclogenesis in the region. Hence, less tropical cyclone activity compared to\nthe Bay of Bengal.\n\n[\nhttp:\/\/www.meted.ucar.edu\/tropical\/textbook_2nd_edition\/print_3.htm#page_5.3.0\n](http:\/\/www.meted.ucar.edu\/tropical\/textbook_2nd_edition\/print_3.htm#page_5.3.0)\n(Need account to login) [\nhttp:\/\/www.nature.com\/nature\/journal\/v479\/n7371\/full\/nature10552.html#ref1\n](http:\/\/www.nature.com\/nature\/journal\/v479\/n7371\/full\/nature10552.html#ref1)\n(First line)"}
{"query":"I was reading this article about Zealandia and got excited that there could be an underwater continent. However, when viewing the image (below) it appears that Zealandia is much smaller than any other continent. The article says the bases considered were:\n\nelevation above the surrounding area\ndistinctive geology\na well-defined area\na crust thicker than the regular ocean floor\nIs there some criteria on size that should be met to be classified as a continent? If so, does Zealandia meet that criteria? Or, is it possible that Zealandia is a continental fragment?","reasoning":"Zelandia meets the criteria of being a continent. ","id":"51","excluded_ids":["N\/A"],"gold_ids_long":["zealandia\/GSATG321A_1_htm.txt"],"gold_ids":["zealandia\/GSATG321A_1_htm4.txt","zealandia\/GSATG321A_1_htm3.txt"],"gold_answer":"$\\begingroup$\n\nIn the [ GSA Today article\n](http:\/\/www.geosociety.org\/gsatoday\/archive\/27\/3\/article\/GSATG321A.1.htm)\nthat Michael linked to in the comments, it says:\n\n> The Glossary of Geology defines a continent as \u201cone of the Earth\u2019s major\n> land masses, including both dry land and continental shelves\u201d (Neuendorf et\n> al., 2005). It is generally agreed that continents have all the following\n> attributes:\n>\n>   1. high elevation relative to regions floored by oceanic crust;\n>   2. a broad range of siliceous igneous, metamorphic, and sedimentary rocks;\n>   3. thicker crust and lower seismic velocity structure than oceanic crustal\n> regions; and\n>   4. **well-defined limits around a large enough area to be considered a\n> continent rather than a microcontinent or continental fragment.**\n>\n\n>\n> The first three points are defining elements of continental crust and are\n> explained in many geoscience textbooks and reviews (e.g., Holmes, 1965;\n> Christensen and Mooney, 1995; Levander et al., 2005; Kearey et al., 2009;\n> Condie, 2015). **To our knowledge, the last point\u2014how \u201cmajor\u201d a piece of\n> continental crust has to be to be called a continent\u2014is almost never\n> discussed, Cogley (1984) being an exception** .\n\nand goes on to mention:\n\n> Further\u00admore, the 4.9 Mkm^2 area of continental crust is large and separate\n> enough to be considered not just as a continental fragment or a\n> microcontinent, but as an actual continent\u2014Zealandia. This is not a sudden\n> discovery but a gradual realization; as recently as 10 years ago we would\n> not have had the accumulated data or confidence in interpretation to write\n> this paper.\n\nThis part is important too:\n\n> spatial and tectonic separation, along with intervening oceanic crust, means\n> that the Zealandia continental crust is physically separate from that of\n> Australia. If the Cato Trough did not exist, then the content of this paper\n> would be describing the scientific advance that the Australian continent was\n> 4.9 Mkm2 larger than previously thought.\n\nSo to wrap it up, they say:\n\n> Being >1 Mkm^2 in area, and bounded by well-defined geologic and geographic\n> limits, Zealandia is, by our definition, large enough to be termed a\n> continent. At 4.9 Mkm^2, **Zealandia is substantially bigger than any\n> features termed microcontinents and continental fragments, ~12\u00d7 the area of\n> Mauritia and ~6\u00d7 the area of Madagascar** . It is also substantially larger\n> than the area of the largest intraoceanic large igneous province, the Ontong\n> Java Plateau (1.9 Mkm^2)."}
{"query":"Tetens coefficients appear in a few meteorological\/climatological models that I've been looking at,for example APSIM:\n\nsvp_A = 6.106\nsvp_B = 17.27\nsvp_C = 237.3\nThese same values appear in at least two other models, but I can't find any documentation about what they represent, or where they come from. What are these numbers?","reasoning":"The Tetens coefficents are the empirically derived coefficients of an equation for calculating the saturation vapour pressure of water.","id":"52","excluded_ids":["N\/A"],"gold_ids_long":["teten\/Clausius_E2_80_93Clapeyron_relation.txt"],"gold_ids":["teten\/Clausius_E2_80_93Clapeyron_relation5.txt"],"gold_answer":"$\\begingroup$\n\nThe Tetens coefficents are the empirically derived coefficients of an equation\nfor calculating the saturation vapour pressure of water. From [ wikipedia\n](https:\/\/en.wikipedia.org\/wiki\/Clausius%E2%80%93Clapeyron_relation#Meteorology_and_climatology)\n:\n\n> a very good approximation can usually be made using the August-Roche-Magnus\n> formula (usually called the Magnus or Magnus-Tetens approximation, though\n> this attribution is historically inaccurate):\n>\n> $e_s(T)= 6.1094 \\exp \\left( \\frac{17.625T}{T+243.04} \\right)$\n>\n> e_s(T) is the equilibrium or saturation vapor pressure in hPa as a function\n> of temperature T on the Celsius scale. Since there is only a weak dependence\n> on temperature of the denominator of the exponent, this equation shows that\n> saturation water vapor pressure changes approximately exponentially with T."}
{"query":"According to the Mariana Trench Oceanography page is at a maximum depth of\n\nis 11,033 meters (36,201 feet)\n\nThe 'Challenger Deep' being the name of the deepest point.\n\nI understand that it is a subduction trench, but my question is, what geological mechanism result in the great depth of the Mariana Trench over other trenches?","reasoning":"the supply of sediment, the age of the lithosphere at the time of subduction, narrow slabs sinking and rolling back more rapidly than broad plates, causing the great depth of the mariana trench. ","id":"53","excluded_ids":["N\/A"],"gold_ids_long":["mariana_trench\/Oceanic_trench.txt"],"gold_ids":["mariana_trench\/Oceanic_trench1.txt","mariana_trench\/Oceanic_trench2.txt"],"gold_answer":"$\\begingroup$\n\nAs taken from [ Wikipedia ](https:\/\/en.wikipedia.org\/wiki\/Oceanic_trench) :\n\n> There are several factors that control the depth of trenches. The most\n> important control is **the supply of sediment** , which fills the trench so\n> that there is no bathymetric expression. It is therefore not surprising that\n> the deepest trenches (deeper than 8,000 m (26,000 ft)) are all\n> nonaccretionary. In contrast, all trenches with growing accretionary prisms\n> are shallower than 8,000 m (26,000 ft).\n>\n> A second order control on trench depth is **the age of the lithosphere at\n> the time of subduction** . Because oceanic lithosphere cools and thickens as\n> it ages, it subsides. The older the seafloor, the deeper it lies and this\n> determines a minimum depth from which seafloor begins its descent. This\n> obvious correlation can be removed by looking at the relative depth, the\n> difference between regional seafloor depth and maximum trench depth.\n> Relative depth may be controlled by the age of the lithosphere at the\n> trench, the convergence rate, and the dip of the subducted slab at\n> intermediate depths.\n>\n> Finally, **narrow slabs can sink and roll back more rapidly than broad\n> plates** , because it is easier for underlying asthenosphere to flow around\n> the edges of the sinking plate. Such slabs may have steep dips at relatively\n> shallow depths and so may be associated with unusually deep trenches, **such\n> as the _Challenger Deep_ ** .\n\n  \n\nA simple picture for anyone who doesn't understand how these trenches form: [\n![Oceanic trench](https:\/\/i.sstatic.net\/oFeRh.gif)\n](https:\/\/i.sstatic.net\/oFeRh.gif)  \n(source: [ wikispaces.com\n](https:\/\/sjesci.wikispaces.com\/file\/view\/trench.gif\/148041157\/trench.gif) )\n\nAlso, the Mariana Trench isn't the only super deep trench in the ocean... [ 10\ndeepest parts of the ocean ](https:\/\/www.marineinsight.com\/know-\nmore\/10-deepest-parts-of-the-ocean\/)"}
{"query":"Bohrmann et al. 1989 advanced the idea that the silicate phase from some clinoptilolites come from the diagenetic degradation of biogenic opal (from radiolarians in that case but presumably also other siliceous microfossils).\n\nIf this hypothesis is still regarded as valid, is clinoptilolite the only kind of authigenic zeolite that can be traced to biogenic opal?\n\nHas any work been done in that domain since this paper?\n\n","reasoning":"clinoptilolite is the only kind of authigenic zeolite that can be traced to biogenic opal. clinoptilote and heulandite occur in Si-rich diagenetic environments.","id":"54","excluded_ids":["N\/A"],"gold_ids_long":["authigenic_zeolites\/om.txt"],"gold_ids":["authigenic_zeolites\/om2.txt"],"gold_answer":"$\\begingroup$\n\nYes, there have been recent research in this field.\n\nIn the article [ Oceanic minerals: Their origin, nature of their environment,\nand significance ](http:\/\/www.pnas.org\/content\/96\/7\/3380.full.pdf) (Kastner,\n1999), who asserts that\n\n> The zeolites phillipsite and analcime mostly reflect on diagenesis of\n> volcanic matter; **clinoptilote and heulandite occur in Si-rich diagenetic\n> environments.**\n\nand confirm that\n\n> In addition to diagenetic opal-CT and quartz that form from the dissolution\n> of biogenic opal-A, other common authigenic alumino-silicate minerals are\n> smectites and zeolites.\n\nThis is further confirmed by a 2007 paper [ Clinoptilolite as a new proxy of\nenhanced biogenic silica productivity in lower Miocene carbonate sediments of\nthe Bahamas platform: Isotopic and thermodynamic evidence\n](http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0009254107003804) (Karpoff\net al) which determined that\n\n> Seawater\u2013rock modeling specifies that clinoptilolite precipitates from the\n> dissolution of biogenic silica, which reacts with clay minerals. The amount\n> of silica (opal-A) involved in the reaction has to be significant enough, at\n> least 10 wt.%, to account for the observed content of clinoptilolite\n> occurring at the most zeolite-rich level. Modeling also shows that the\n> observed amount of clinoptilolite (\u223c 19%) reflects an in situ and short-term\n> reaction due to the high reactivity of primary biogenic silica (opal-A)\n> until its complete depletion."}
{"query":"Currently it is winter in Antarctica. According to news I read, Antarctica has set a new record high temperature, above 18 \u00b0C. How did this temperature records occur?\n","reasoning":"The author says that in the winter the hottedt weather in Antarctica is 18 celsius degree. But the fact is that that's the hottest temperature of summer there. ","id":"55","excluded_ids":["N\/A"],"gold_ids_long":["hottest_antarctic\/wmo.txt"],"gold_ids":["hottest_antarctic\/wmo3.txt"],"gold_answer":"$\\begingroup$\n\nYou just read the news too fast. WMO [ announced\n](https:\/\/public.wmo.int\/en\/media\/press-release\/wmo-verifies-one-temperature-\nrecord-antarctic-continent-and-rejects-another) that, after evaluation by a\ncommittee, they have validated the 18.3\u00b0C temperature recorded _in February_\n(i.e., in summer) last year:\n\n> GENEVA, 1 July 2021 (WMO) - The World Meteorological Organization (WMO) has\n> recognized a new record high temperature for the Antarctic continent of\n> 18.3\u00b0 Celsius on 6 February 2020 at the Esperanza station (Argentina)."}
{"query":"What causes the typical red, pink or orange colors seen in sun-rises and sun-sets?\n\nHow come the sky doesn't just turn a darker blue?","reasoning":"The reason why the sky is red or other colors during the sunset is the phenomenon called  Rayleigh scattering. ","id":"56","excluded_ids":["N\/A"],"gold_ids_long":["sunset_color\/Sunset.txt","sunset_color\/Rayleigh_scattering.txt"],"gold_ids":["sunset_color\/Rayleigh_scattering3.txt","sunset_color\/Rayleigh_scattering4.txt","sunset_color\/Rayleigh_scattering5.txt","sunset_color\/Rayleigh_scattering2.txt","sunset_color\/Sunset4.txt"],"gold_answer":"$\\begingroup$\n\nThere are many references about this on the web, such as [ Wikipedia\n](https:\/\/en.wikipedia.org\/wiki\/Sunset) and the [ NOAA\n](http:\/\/www.spc.noaa.gov\/publications\/corfidi\/sunset\/) site.\n\nAt sunrise and sunset the angle the Sun's light makes with the Earth at those\nlocations is low compared with angle the light makes at midday. Because of the\nlow angle, the light has to travel through more of the atmosphere before it\nreaches the Earth's surface and the eyes of anyone watching either the Sun\nrise or the Sun set.\n\nThe colour of the Sun's light is white, being composed of the colours of the\nlight spectrum: red, orange, yellow, green, blue, indigo and violet. The [\nwavelength ](http:\/\/science-\nedu.larc.nasa.gov\/EDDOCS\/Wavelengths_for_Colors.html) of these component\ncolours are all different. Red has the longest wavelength at 650 nm. Each of\nthe other colours have shorter wavelengths with violet having the shortest at\n400 nm.\n\nAs the Sun's light passes through the atmosphere it get scattered by the air\nmolecules and particles in the air such as dust and aerosols.\n\nDue to a phenomenon known as [ Rayleigh scattering\n](https:\/\/en.wikipedia.org\/wiki\/Rayleigh_scattering) the shorter wavelengths\nof light (greens, blues, violets) are scattered first, leaving the shorter\nwavelengths (yellows, oranges and reds) to travel further.\n\nThe greater the amount of particles in the air, dust and aerosols, the greater\nthe degree of scattering and the more red the sunrises and sunsets will\nappear. This is particularly evident after large amounts of ash have been\nejected by [ volcanoes ](http:\/\/www.livescience.com\/12834-iceland-volcano-\nfiery-sunsets.html) , after large forest fires and in locations where [ air\npollution ](http:\/\/www.economist.com\/blogs\/babbage\/2014\/04\/air-pollution) ,\nparticularly from industrial chimney stacks and internal combustion engines\nfrom road vehicles is a major source of airborne [ particulate\n](http:\/\/www.scientificamerican.com\/article\/fact-or-fiction-smog-creates-\nbeautiful-sunsets\/) matter such as soot or ash and other very small products\nof combustion"}
{"query":"If I wanted to make an air shield around the earth to contain exactly half the planet's atmosphere (by mass), how far above sea level would I have to build it?\n\nIt's slightly complicated to me because you have to take into consideration the change in pressure as well as the geometric growth of the volume of a sphere as you increase the radius.\n\nThank you.","reasoning":"The author wants to find out the distance to cross the atmosphere, which can be solved through hydrostatic function.","id":"57","excluded_ids":["N\/A"],"gold_ids_long":["beyond_atmosphere\/atmthick_html.txt","beyond_atmosphere\/Vertical_pressure_variation.txt"],"gold_ids":["beyond_atmosphere\/Vertical_pressure_variation5_2.txt","beyond_atmosphere\/Vertical_pressure_variation5_0.txt","beyond_atmosphere\/Vertical_pressure_variation5_1.txt","beyond_atmosphere\/atmthick_html4.txt","beyond_atmosphere\/Vertical_pressure_variation4.txt","beyond_atmosphere\/atmthick_html3.txt","beyond_atmosphere\/Vertical_pressure_variation3.txt","beyond_atmosphere\/atmthick_html2.txt"],"gold_answer":"$\\begingroup$\n\nRoughly 5.5 km, although the exact value depends on the weather. All you need\nto do is to [ solve the hydrostatic equation\n](https:\/\/en.wikipedia.org\/wiki\/Vertical_pressure_variation) and find the\nheight at which the pressure is 50% of the height at sea level (or perhaps\naverage elevation of Earth surface instead of sea level). Any answer actually\nperforming the calculation deserves upvotes more than I do ;-)\n\nSee, for example, [ Thickness of Earth's Atmosphere\n](http:\/\/www.pdas.com\/atmthick.html) :\n\n> Using boundary layer theory as an example, we can define the thickness of\n> the atmosphere to be the altitude that encloses 99 percent of the total mass\n> of the atmosphere. Looking at the chart, we can see that this seems to be\n> about 31 kilometers. The halfway point, where half the mass of the\n> atmosphere is below and half above occurs at 5.5 kilometers. Another\n> interesting fact is that when you are cruising in a modern jet transport at\n> 11 kilometers, you are above 77.5 percent of the atmosphere. The total mass\n> of the atmosphere turns out to be 5.3 zettagrams (5.3 Zg).\n\nI'm not entirely sure how the calculations in the linked article are\nperformed, but I recall calculating this as a student and ending up somewhere\naround 5 km, so it sounds right. Simple calculations often assume an\nisothermal atmosphere, which is of course not accurate, but good enough if you\ndon't need to know the answer more precisely than within several hundred\nmetre.\n\n[ This page at Stanford reaches the same number.\n](http:\/\/nova.stanford.edu\/projects\/mod-x\/id-pres.html)"}
{"query":"I would like to calculate the latitude values of a Gaussian Grid of a size of my choosing. Unfortunately, I didn't find a method or a formula to do so. Where can I find this information? Alternatively, is there a function publicly available that can do the job?","reasoning":"NCL gaus fuction is  a good way for calculating latitudes of gaussian grid.","id":"58","excluded_ids":["N\/A"],"gold_ids_long":["gaussian_grid\/gaus_shtml.txt"],"gold_ids":["gaussian_grid\/gaus_shtml3.txt","gaussian_grid\/gaus_shtml2.txt"],"gold_answer":"$\\begingroup$\n\nI believe the NCL function [ NCL gaus\n](http:\/\/www.ncl.ucar.edu\/Document\/Functions\/Built-in\/gaus.shtml) should be\nable to give you the solution you are looking for. From the API documentation\nyou are requested to provide - the number of latitude points per hemisphere\nand you should get Gaussian latitudes and Gaussian weights.\n\nHere is a code sample from their website\n\n    \n    \n    nlat = 64  ; for globe\n    gau_info = gaus(nlat\/2)   ; divide by 2 to get \"per hemisphere\"\n    glat     = gau_info(:,0)  ; gaussian latitudes ( 1st dimension of gau_info)\n    gwgt     = gau_info(:,1)  ; gaussian weights   ( 2nd dimension of gau_info)"}
{"query":"I'm confused by what exactly a CDL file is and what its purpose is. Unidata specifies the syntax of such a CDL file in its netCDF documentation.\n\nQuestions:\nAre CDL files designed to be opened by a simple text editor like Notepad or gedit? Or should I use some other tool to open it?\n\nWhat is its purpose and how is it used?","reasoning":"A CDL file is basically a text output from a netcdf file.","id":"59","excluded_ids":["N\/A"],"gold_ids_long":["cdf_file\/washington.txt"],"gold_ids":["cdf_file\/washington3.txt","cdf_file\/washington2.txt","cdf_file\/washington4.txt"],"gold_answer":"$\\begingroup$\n\nA CDL file is basically a text output from a netcdf file. If you want to know\nthe contents of a netcdf file but don't have the time (or ability) to use\nprograms built to read\/write netcdf, you can use the simple text output of\n\"ncdump\" and then read\/write it with a basic text editor. You can also use\n\"ncgen\" to regenerate a netcdf file based on the new CDL file. I've used this\nprocess to make simple changes to netcdf files, and it works very quickly\ncompared to generating a netcdf file using programming methods.\n\nSee [ http:\/\/www.atmos.washington.edu\/ive\/ive_help\/writing_netCDF_files.html\n](http:\/\/www.atmos.washington.edu\/ive\/ive_help\/writing_netCDF_files.html) ,\nquoted below:\n\n> A CDL (network Common data form Description Language) file is an ASCII\n> descripton of the binary data in a netCDF file that is designed to be easily\n> read by humans. CDL files can be generated from netCDF files via the\n> `ncdump', command. For example,\n>\n> ncdump -c sample.nc generates the file `sample.cdl' that contains the file\n> name, the dimensions, the specification of the variables, any attributes and\n> the data for any \"coordinate variables.\" A CDL file of this type is shown\n> below. Note that the double slash indicates a comment in the CDL file.\n>\n> netcdf implicit_grid{\n>\n> dimensions: lon = 101; lat = 101; level = 5; time = UNLIMITED ; \/\/(7\n> currently) variables:\n>\n> float A(time,level,lat,lon); A:units = \"meters\/second\"; float level(level);\n>\n> level:units = \"millibars\"; float time(time);\n>\n> time:units = \"hours\"; \/\/global attributes:\n>\n> :x_min = -180.f; :x_max = 180.f; :x_units = \"degrees_east\"; :x_label =\n> \"longitude\"; :y_min = -90.f; :y_max = 90.f; :y_units = \"degrees_north\";\n> :y_label = \"latitude\";\n>\n> :z_label = \"level\"; :t_label = \"time\";\n>\n> data: level = 1000, 850, 700, 500, 300 ; time = 0, 2, 4, 6, 8, 10, 12 ;\n>\n> The command ` ncgen' is the inverse of ` ncdump'; it converts an ASCII CDL\n> file to a binary netCDF file. For example\n>\n> ncgen -o sample.nc sample.cdl converts the CDL file ` sample.cdl' to the\n> netCDF file ` sample.nc'. The easiest way to create a netCDF file is to (1)\n> write all the header data (the name, dimensions, variable and attribute\n> specifications, and the values of any coordinate variables) to a CDL file,\n> (2) convert the CDL file to a netCDF file using ncgen, and (3) continue\n> writing the main data arrays to this netCDF file."}
{"query":"I know volcanologists study volcanoes. Is there a subdiscipline that only studies maga or lava? A magmatologist?","reasoning":"Igneous Petrologists is a subdiscipline that only studies maga or lava of volcanology.","id":"60","excluded_ids":["N\/A"],"gold_ids_long":["igneous_petrologists\/Igneous_petrology.txt"],"gold_ids":["igneous_petrologists\/Igneous_petrology4.txt"],"gold_answer":"$\\begingroup$\n\nPerhaps they are called [ Igneous Petrologists\n](http:\/\/en.wikipedia.org\/wiki\/Igneous_petrology) ?\n\nSomeone who studies magma\/lava flows tends to go by Geophysicist because they\ninherently study continuum mechanics and fluid flow."}
{"query":"Someone I know posted a question about climate change that I do not know how to answer. While I do believe (for lack of better word) in climate change, I do not know how to answer this persons question. The tl;dr of the question is:\n\nIf climate change is not a natural phenomenon, then how did the last ice age end?\n\nThe person is implying that warming\/cooling reoccurs periodically on the Earth, and that the current climate change threat is overblown.\n\nI have searched online for answers, but cannot find anything concise on this specific subject. According to this wikipedia article,\n\nThere is evidence that greenhouse gas levels fell at the start of ice ages and rose during the retreat of the ice sheets, but it is difficult to establish cause and effect (see the notes above on the role of weathering). Greenhouse gas levels may also have been affected by other factors which have been proposed as causes of ice ages, such as the movement of continents and volcanism.\n\nIn short, how and why did the last ice ages end? I am assuming that the carbon dioxide concentration during these ice ages is much lower than the current estimate of ~410 ppm. Aside from the difference in carbon dioxide levels, what evidence suggests that the climate change of today is different than the climate change that ended the ice age(s)?","reasoning":"There are two ways that the climate change today is different from the ice age: speed and civilization","id":"61","excluded_ids":["N\/A"],"gold_ids_long":["difference_in_climate_change\/ripple_effects_population_and_coastal_regions.txt","difference_in_climate_change\/low_res.txt"],"gold_ids":["difference_in_climate_change\/low_res2.txt","difference_in_climate_change\/ripple_effects_population_and_coastal_regions5.txt","difference_in_climate_change\/ripple_effects_population_and_coastal_regions3.txt","difference_in_climate_change\/ripple_effects_population_and_coastal_regions4.txt"],"gold_answer":"$\\begingroup$\n\nDifference #1: **Speed** . The warming at the end of the ice ages went much,\nmuch slower than what we are currently experiencing.\n\nEstimates of the amount of warming since the beginning of the industrial\nrevolution are [ in the order or 1 degree Celsius\n](https:\/\/www.ipcc.ch\/site\/assets\/uploads\/sites\/2\/2018\/12\/SR15_FAQ_Low_Res.pdf)\n*  \\- that's in 100-150 years time.\n\n* Page 7 \n\n> When the Earth moved out of ice ages over the past million years, the global\n> temperature rose a total of 4 to 7 degrees Celsius over about 5,000 years.\n\n(NASA Source: [ How is Today\u2019s Warming Different from the Past?\n](https:\/\/earthobservatory.nasa.gov\/features\/GlobalWarming\/page3.php) )\n\nThe article [ Earth is warming 50x faster than when it comes out of an ice age\n](https:\/\/www.theguardian.com\/environment\/climate-consensus-97-per-\ncent\/2016\/feb\/24\/earth-is-warming-is-50x-faster-than-when-it-comes-out-of-an-\nice-age) sums it up nicely:\n\n> What humans are in the process of doing to the climate makes the transition\n> out of the last ice age look like a casual stroll through the park. We\u2019re\n> already warming the Earth about 20 times faster than during the ice age\n> transition, and over the next century that rate could increase to 50 times\n> faster or more. We\u2019re in the process of destabilizing the global climate far\n> more quickly than happens even in some of the most severe natural climate\n> change events.\n>\n> That rapid climate destabilization is what has climate scientists worried.\n> It\u2019s faster than many species can adapt to, and could therefore cause\n> widespread extinctions, among other dangerous climate change consequences.\n> Coastal flooding in places like Florida has already become much more common\n> than it was just 50 years ago, and sea level rise is expected to keep\n> accelerating.\n\nDifference #2: **Civilization** . At the end of the ice ages we did not have [\n3 billion people living within 200 km from a coast line\n](https:\/\/www.prb.org\/rippleeffectspopulationandcoastalregions\/)  \nThat is not an difference in the _cause_ of the warming, but definitely in the\n_effect_ .\n\nOne could argue that that same civilization will make us able to deal with the\nconsequences, but looking at thing that already exists several centuries\nwithout change, surely raises doubts to our ability to deal with the current\nrate of climate change. Think (1) unequal global wealth distribution or (2)\nthe psychology of our behavior (denial, politics).\n\n* * *\n\nBTW The question asked to you\n\n> If climate change is not a natural phenomenon, then how did the last ice age\n> end?\n\nis based on a false premise - it's a bit of a word game.  \nThe current warming is _still_ a natural phenomenon, but it's now [ primarily\ndriven by _our_ input, and not other 'natural' phenomena\n](https:\/\/www.britannica.com\/science\/climate-change\/Evidence-for-climate-\nchange) ."}
{"query":"I've heard long ago that the rock material deeply below surface are checked by a device that acts like radar - it sends radiowaves into the ground, and geologists find out from reflections that what type of rock can be found there.\n\nWhat's the name of this device or method, and how is it possible to differentiate rocks from radiowave reflection?","reasoning":"The post wants to know how detect different rocks with radio waves. Ground panetrating radar can solve this problem. ","id":"62","excluded_ids":["N\/A"],"gold_ids_long":["bedrock_with_radiowaves\/Ground_penetrating_radar.txt"],"gold_ids":["bedrock_with_radiowaves\/Ground_penetrating_radar4.txt"],"gold_answer":"$\\begingroup$\n\nDo you mean [ Ground Penetrating Radar ](http:\/\/en.wikipedia.org\/wiki\/Ground-\npenetrating_radar) ? This is typically limited to very shallow depths though -\neg. archaeological investigations, police forensics (finding graves), and\ncivil engineering site investigations. The latter can go to tens of meters and\nwould be used for planning foundations, excavations, etc (I know of an example\nwhere it was used for site characterization for a planned rowing lake). The\ndepth limit is typically due to attenuation in brackish groundwaters. Ice\napplications can typically go further due to the lack of conducting liquid\nwater.\n\nOr are you thinking of [ Reflection ('Active') Seismic Surveys\n](http:\/\/principles.ou.edu\/seismic_explo\/reflect\/reflect.html) , which work on\na similar principle but using sound waves. Sound waves can travel to the far\nside of the Earth (cf. large earthquake 'P' waves), but reflection surveys are\ntypically looking at the upper crust (few km) and rarely go beyond the base of\nthe crust (aka the 'Moho') which is a strong seismic reflector. Reflection\nseismic surveys are widely used in the oil business."}
{"query":"Are there any resources (books\/links) that discuss the mathematical tools and methods used to forecast the aurora borealis activity in a particular location?\n\nI see many websites that claim to predict aurora, but are there any open source code that lets you have an idea of the models?","reasoning":"OVATION is a model to predict the aurora.","id":"63","excluded_ids":["N\/A"],"gold_ids_long":["predicting_aurora\/Backronym.txt","predicting_aurora\/agu.txt","predicting_aurora\/ovation.txt"],"gold_ids":["predicting_aurora\/ovation3.txt","predicting_aurora\/Backronym4.txt","predicting_aurora\/agu1.txt","predicting_aurora\/agu5.txt"],"gold_answer":"$\\begingroup$\n\n**One model is the[ OVATION auroral precipitation model ](http:\/\/sd-\nwww.jhuapl.edu\/Aurora\/ovation\/) . **\n\nOVATION [ stands for ](https:\/\/en.wikipedia.org\/wiki\/Backronym) Oval\nVariation, Assessment, Tracking, Intensity, and Online Nowcasting.\n\nThe [ NOAA Space Weather Prediction Center ](http:\/\/www.swpc.noaa.gov\/) uses\nthe OVATION Prime model for their 30-minute aurora forecast. They use a\nmodified version of the model for their [ 3-day forecast\n](http:\/\/www.swpc.noaa.gov\/products\/aurora-3-day-forecast) . It was devised by\nNewell et al. (2010) at Johns Hopkins University.\n\nYou can read all about it in Machol et al. (2013). [ The paper\n](http:\/\/onlinelibrary.wiley.com\/doi\/10.1029\/2011SW000746\/full) is open access\nand contains several equations and a description of the method. They explain:\n\n> The OVATION Prime model is derived from electron and proton flux\n> measurements from the SSJ4 detectors on the [ DMSP satellites\n> ](https:\/\/en.wikipedia.org\/wiki\/Defense_Meteorological_Satellite_Program) .\n\nSSJ4 sensors, according to [ one source\n](http:\/\/www.ferzkopp.net\/Personal\/Thesis\/node28.html) :\n\n> [...consist] of an array of four cylindrical, curved plate, electrostatic\n> analyzers configured into two pairs; one pair each to measure electrons and\n> ions. Each pair covers the energy range from 30 eV to 30 keV in 20 channels\n> spaced at equal intervals in energy on a logarithmic scale.\n\n###  References\n\nMachol, J. L., J. C. Green, R. J. Redmon, R. A. Viereck, and P. T. Newell\n(2012), Evaluation of OVATION Prime as a forecast model for visible aurorae,\nSpace Weather, 10, S03005, [ doi:10.1029\/2011SW000746\n](http:\/\/onlinelibrary.wiley.com\/doi\/10.1029\/2011SW000746\/full) .\n\nNewell, P. T., T. Sotirelis, and S. Wing (2010a), Seasonal variations in\ndiffuse, monoenergetic, and broadband aurora, J. Geophys. Res., 115, A03216, [\ndoi:10.1029\/2009JA014805\n](http:\/\/onlinelibrary.wiley.com\/doi\/10.1029\/2009JA014805\/full) ."}
{"query":"I got caught in a downpour while climbing a mountain and was amazed to see, as I climbed down, the tiny trickles of water combine to form mini-streams, the dry rocks I had climbed up now hosted sizable waterfalls, and the path which I had followed to the mountain had become a small river.\r\n\r\nBut it got me wondering about my question, which is the reverse of this. Why, after a long period of dry weather, are many rivers still flowing? I live near a river and it seems that it takes over a week of dry weather before there's any noticeable drop in its level. How does it not simply run out of water? Is it simply that it takes very a long time for the water at its source and the sources of all its tributaries to reach the point I'm observing from?\r\n\r\nIt seems there's a constant supply of water when I would have expected the network of rivers to start draining, and the drying up starting from the source the moment the rain stopped.","reasoning":"The rivers are generally fed by water that percolated into the ground, which helps it last during the dry season.","id":"64","excluded_ids":["N\/A"],"gold_ids_long":["dry_weather_river\/usgov.txt"],"gold_ids":["dry_weather_river\/usgov3.txt","dry_weather_river\/usgov2.txt"],"gold_answer":"$\\begingroup$\n\nThe rivers are generally fed by water that percolated into the ground, it\ntakes longer for that water to work its way down to the stream so the streams\nand rivers keep flowing long after the initial rain. [\nhttps:\/\/water.usgs.gov\/edu\/rivers-contain-groundwater.html\n](https:\/\/water.usgs.gov\/edu\/rivers-contain-groundwater.html)"}
{"query":"I am trying to understand the concrete process of how a meteorologist at a weather forecast office produces the different types of weather forecasts. I understand how numerical weather models work, but I would like to learn how the model output is turned into a forecast and to what extend it is improved by a skilled meteorologist.\r\n\r\nI have found an older reference from 1993 that has some information on the workflow, https:\/\/esrl.noaa.gov\/gsd\/eds\/gfesuite\/pubs\/AWIPS-Forecast-Preparation-System.pdf but this is probably outdated and doesn't talk about the meteorological side.\r\n\r\nThere are a lot of different forecast products from text to graphical products, so my question might be an overly broad one, but I haven't found much information so far, so I don't want to be too restrictive.\r\n\r\nWhat concrete model outputs do forecasters look at and to what extend do they use local observations and experience?","reasoning":"Scientists review observations using radar, satellites, and other instruments. Forecasters analyze this data, create graphical representations, and use various models to predict changes. They review model output daily, selecting the most accurate or blending different models for optimal results.","id":"65","excluded_ids":["N\/A"],"gold_ids_long":["weather_forcast\/forecast_process.txt"],"gold_ids":["weather_forcast\/forecast_process4.txt"],"gold_answer":"$\\begingroup$\n\nThe Virtual tour is good, and I don't know why that wasn't an accepted answer.\nSo I'll throw my answer into the ring. I'll recommend you try the [ NWP and\nForecasting Comet module ](https:\/\/www.meted.ucar.edu\/bom\/intro_nwp\/index.htm)\n(it's free if to get an account). That'll probably help more than my answer,\nwhich is based around the forecasting classes that I took and my experience as\na forecaster in the university's student-run weather service.\n\nFrom the outside, the forecast process is a very mysterious thing. But in\nreality it is not. Though, it is highly a subjective task and is subject to\nsome degree of variation per person (hence some people are better forecasters\nthan others). It also takes a lot of time to do it right. Here is my pattern\nif I want to be rigorous.\n\n  1. Know where I am forecasting for. \n\nLocation is important. What do I know about the climatology. Climatology can\ngive a \"first guess\" on the range of values that can be reasonably considered.\nThe previous day's weather can also be a good first guess. If I am well\nacquainted with the area, then this becomes a shorter and shorter step.\n\n  2. Start with observations. \n\nWhat is happening now? What is reality saying? The amount of space that is\nlooked at needs to be proportionate to the forecast time.\n\n  3. Make inferences on the current state and causes of weather features. \n\nWhat patterns are seen? Was map analysis done? Are there certain areas that\nare colder than others? Are there places that have clouds and others that\ndon't have clouds? What does the radar say? Why, why why why why? If you know\nthe mechanisms that are generating weather now, then you can understand how\nthey might evolve.\n\n  4. Examine how the weather models have started. \n\nBefore you use a weather model, you should understand it. Garbage in=garbage\nout, _sometimes_ . How well did the model do today? If it is overpredicting\ntemperature right now, will it continue overpredicting the temperature? Will\nthe errors that occurred upstream yesterday occur today?\n\n  5. Look at how the weather models progress. Question if it aligns with my knowledge and experience. \n\nTaking a model at face value might work for research purposes (unless you are\nresearching the model itself), but shouldn't be done on a practical level or\nin a rush. What does Model Output Statistics (MOS) say?\n\n  6. Choose the right numbers or features. \n\nThis is probably the step that requires the least amount of explanation.\nThough the more intricate the type of forecast, the harder and harder this\nbecomes. Does it actually require numbers, or is there some sort of GIS\nsoftware (like for hurricane trajectory or lightning forecast)?\n\n  7. Verify \n\nThis can't be stated enough. You must verify how well you did. Decisions need\nto be made on how the forecast will be verified. What data sources do you know\nof for verification? If I could move this up to number 1 and still have this\nmake sense, I would. Because this is what you should start off with. This\nactually goes part and parcel with starting with observations, since\nobservations are what you start a forecast with. Understand the processes of\nwhy your forecast was off. This will serve you in the future and in the next\nforecast."}
{"query":"In Pangaea, northern Africa would have had humid onshore winds from the Tethys Ocean, making dense vegetation\/rainforest biome likely.\r\n\r\nConsequently, would we be likely to find coal underneath the Sahara desert?","reasoning":"Much of the Sahara is covered with limestone, the possibility that there are coal mines under sahara desert is small.","id":"66","excluded_ids":["N\/A"],"gold_ids_long":["coal_under_sahara\/_google_vignette.txt"],"gold_ids":["coal_under_sahara\/_google_vignette4.txt"],"gold_answer":"$\\begingroup$\n\nThe older rocks underlying the [ Sahara ](https:\/\/geography.name\/the-geology-\nof-the-sahara\/)\n\n> are mostly granite, schist, or gneiss, all mixtures of igneous and\n> metamorphic rocks forged deep beneath the surface\n>\n> This stable mass of rock has been covered over with younger sediments, laid\n> down in horizontal, largely unaltered layers. **Much of the Sahara is\n> covered with limestone** , made mostly of the skeletons of microscopic sea\n> creatures raining down onto the bottom of a vanished sea.\n>\n> Most of the limestone and sandstone covering the surface of the Sahara were\n> deposited in the Mesozoic era (245\u201365 million years ago).\n\nFrom the [ picture below\n](https:\/\/pubs.usgs.gov\/of\/2008\/1258\/graphics\/Africa_Coal.png) , produced by\nthe US Geological Survey, most of Africa's coal deposits are in the southern\npart of the continent. There appears to be a very minor coal deposit in\nwestern Algeria with other similar sized deposits in Niger, Mali and Sudan.\nEgypt's Sinai appears to have an exceedingly small deposit of coal from the\nJurassic period.\n\n[ ![enter image description\nhere](https:\/\/pubs.usgs.gov\/of\/2008\/1258\/graphics\/Africa_Coal.png)\n](https:\/\/pubs.usgs.gov\/of\/2008\/1258\/graphics\/Africa_Coal.png)\n\nIn terms of hydrocarbon resources, the Sahara contains about [ 4 percent of\nthe worlds current reserves of oil and gas\n](https:\/\/www.sciencedirect.com\/topics\/earth-and-planetary-sciences\/african-\nplate) . In terms of energy resources, \" [ North Africa is dominant in oil and\ngas ](https:\/\/en.wikipedia.org\/wiki\/Energy_in_Africa) \".\n\n[ ![enter image description here](https:\/\/i.sstatic.net\/ttPR1.png)\n](https:\/\/i.sstatic.net\/ttPR1.png)"}
{"query":"I was reading many articles about estimates of the age of the Earth throughout the ages. I was dumbfounded when I read that Newton, arguably one of the greatest scientists ever to have \u2018calculated\u2019 the age of the earth, estimated that the Earth was created in 4000 BCE. Johannes Kepler arrived at a similar result. Which methods did these scientists use to arrive at such conclusions?","reasoning":"Newton's estimation of the age of the earth actually is consider bible as a historical documentation.","id":"67","excluded_ids":["N\/A"],"gold_ids_long":["newton_estimation\/Dating_creation_Masoretic.txt","newton_estimation\/Chronology_of_the_Bible.txt","newton_estimation\/Ussher_chronology.txt"],"gold_ids":["newton_estimation\/Chronology_of_the_Bible4.txt","newton_estimation\/Dating_creation_Masoretic4.txt","newton_estimation\/Chronology_of_the_Bible3.txt","newton_estimation\/Ussher_chronology4.txt"],"gold_answer":"$\\begingroup$\n\nThe estimates of Newton and Kepler, and the similar estimates of [ dozens of\ntheir contemporaries ](http:\/\/en.wikipedia.org\/wiki\/Dating_creation#Masoretic)\n, were produced by treating the Bible as [ a historically accurate document\n](http:\/\/en.wikipedia.org\/wiki\/Chronology_of_the_Bible) and deriving a\nchronology from it. I think that a detailed explanation of their techniques\nwould be off-topic for Earth Science, but the Wikipedia page on the [ Ussher\nChronology ](http:\/\/en.wikipedia.org\/wiki\/Ussher_chronology) (which provides\nprobably the most famous biblically-based estimate of the Earth's age) goes\ninto reasonable detail about the methods used for such calculations."}
{"query":"How is\/was continental drift monitored?\r\nI am curious about current technology but I am particularly interested in what techniques were employed prior to the advent of satellite technology.","reasoning":"We now use GPS or SLR to observe contenental drift, but before they were invented, we use paleomagnetism.","id":"68","excluded_ids":["N\/A"],"gold_ids_long":["continental_drift\/Paleomagnetism.txt","continental_drift\/Global_Positioning_System.txt","continental_drift\/Satellite_laser_ranging.txt"],"gold_ids":["continental_drift\/Satellite_laser_ranging4.txt","continental_drift\/Global_Positioning_System3.txt","continental_drift\/Global_Positioning_System2.txt","continental_drift\/Paleomagnetism3.txt","continental_drift\/Paleomagnetism4.txt"],"gold_answer":"$\\begingroup$\n\nScientific [ GPS ](http:\/\/www.pocketgpsworld.com\/howgpsworks.php) and [ SLR\n](https:\/\/en.wikipedia.org\/wiki\/Satellite_laser_ranging) have been used for [\nsome time ](http:\/\/onlinelibrary.wiley.com\/doi\/10.1029\/2003JB002944\/full) now,\nand the [ measurements\n](http:\/\/onlinelibrary.wiley.com\/doi\/10.1029\/97JB00514\/pdf) are rather\naccurate. Not only do we measure horizontal movements of tectonic plates, but\nalso uplift as e.g. in the Tibetan and Colorado plateaus.\n\nBefore the GPS was introduced, [ paleomagnetism\n](https:\/\/en.wikipedia.org\/wiki\/Paleomagnetism) were used in some studies to\nestimate the velocities; The age of oceanic crust are estimated by various\nmethods and the travel distance is estimated from the width of the magnetic\npolarized bands in the ocean floor. To understand [ paleogeography\n](http:\/\/www.scotese.com\/earth.htm) and make good models we need to\nincorporate all branches of geology. E.g. [ fossil records\n](https:\/\/en.wikipedia.org\/wiki\/Biostratigraphy) , paleomagnetism, [\nradiometric age estimation ](https:\/\/en.wikipedia.org\/wiki\/Radiometric_dating)\nof rocks.\n\nSome active faults (E.g. San Andreas) can also be directly measured with laser\nranging or, in some cases, with a measurement tape to measure deformation of\ntrenches or railway tracks.\n\nStill, scientists are trying to understand the exact driving forces behind\nplate tectonics. [ Modelling ](http:\/\/www.earthbyte.org\/Resources\/Pdf\/Ghosh-\nHolt-2012-Science-PlateMotionsStressesGlobalDynamicModels.pdf) of [ mantel\ndynamics ](https:\/\/en.wikipedia.org\/wiki\/Mantle_convection) is an interesting\nfield of research and many questions remains."}
{"query":"This is more of a terminological question, but I think it fits here. I've been reading a book by Rachel Carson, from the early 50s, and she uses the phrase \"Archaeozic period\". I haven't seen this used elsewhere - is it just an archaic (pardon the pun) form of \"Archean\", or does it describe a different period? Etymologically, it seems like it's more oriented around \"life\", but that may just be a semantic distinction.","reasoning":"Archaeozoic is just a formal name of Archean, basically they mean the same thing.","id":"69","excluded_ids":["N\/A"],"gold_ids_long":["Archaeozoic_vs_Archean\/archaeozoic.txt","Archaeozoic_vs_Archean\/Archean.txt"],"gold_ids":["Archaeozoic_vs_Archean\/Archean4.txt","Archaeozoic_vs_Archean\/archaeozoic3.txt"],"gold_answer":"$\\begingroup$\n\nThe [ Archaen ](https:\/\/en.wikipedia.org\/wiki\/Archean) was named by American\ngeologist [ James Dwight Dana\n](https:\/\/en.wikipedia.org\/wiki\/James_Dwight_Dana) in 1872, to refer to the\nentire span of time before the Cambrian Period. A synonym was \"Azoic\" as this\nperiod was considered lifeless. Later, it was found that the carbon isotope\nratios changed in rocks about 3.8 billion years old between ones that\nindicated no life present to ones that indicated life. So \"Azoic\" began to\nrefer to the \"lifeless\" period before 3.8 billion years and \"Archaeozoic\" for\nthe \"earliest life\" after that point.\n\nThat's the way it stood when Rachel Carson wrote her book. The 1969 World Book\nEncyclopedia which sat on my parents' bookshelf divided the Precambrian into\nthe [ Proterozoic ](https:\/\/en.wikipedia.org\/wiki\/Proterozoic) , Archaeozioc,\nand Azoic eras.\n\nBy 1972 this wasn't working, so Preston Cloud suggested the term \" [ Hadean\n](https:\/\/en.wikipedia.org\/wiki\/Hadean) \" to refer to the time between the\nformation of the Earth\/Solar System and 4 billion years ago. At the same time,\nthe boundary adjustment caused \"Archean\" to be preferred to \"Archaeozoic\".\n\nBut \"Archaeozoic\" matches up enough to be considered a synonym for \"Archean\"\nthese days.\n\n[ Here's a rabbit hole ](https:\/\/pubs.usgs.gov\/bul\/0769\/report.pdf) (PDF) to\ndive down."}
{"query":"I'm currently doing research for a paper in school where we need to research on a university-like level. When I read the paper Causes and impacts of the 2014 warm anomaly in the NE Pacific, I found the sentence:\r\n\r\nThe wind stress curl was negative, which has precedence but is still quite unusual.\r\n\r\nThe wind stress curl was given as \u22120.5\u2217106 N\u2217m\u22123\r\n. I neither know what wind stress curl is, nor what the negative sign is, nor what the unit of it exactly describes (of course, pressure per meter, but what does that mean?).\r\n\r\nCan anyone explain what it is?","reasoning":"Wind over water creates movement in the upper layers, which transfers to lower layers. Water movement is influenced by the Coriolis force, generally moving to the right of the wind in the northern hemisphere. Divergence and convergence of water occur when there's a difference in wind strength and direction. Negative wind stress curl pushes water downward, suppressing ocean mixing and maintaining warmer upper ocean conditions.","id":"70","excluded_ids":["N\/A"],"gold_ids_long":["wind_stress_curl\/Wilkin20041028_htm.txt"],"gold_ids":["wind_stress_curl\/Wilkin20041028_htm2.txt","wind_stress_curl\/Wilkin20041028_htm1.txt","wind_stress_curl\/Wilkin20041028_htm3.txt","wind_stress_curl\/Wilkin20041028_htm5.txt","wind_stress_curl\/Wilkin20041028_htm4.txt"],"gold_answer":"$\\begingroup$\n\nSkimming the paper, I believe the relevance of the wind stress curl is its\nrelation to \"Ekman pumping\". I haven't found a simple, concise reference for\nthis, but [ this page ](http:\/\/paoc.mit.edu\/labguide\/ekpump.html) might be a\ngood start, and [ this page\n](https:\/\/marine.rutgers.edu\/dmcs\/ms501\/2004\/Notes\/Wilkin20041028.htm) has a\ncouple of formulas about wind stress curl. I'll try to summarize here.\n\nWhen wind blows over water, the top of the water starts moving. It shears\nagainst the water below it, so that water starts moving too. The momentum from\nthe wind is transferred down into lower layers of the water. This water also\nfeels the Coriolis force. The direction it ends up moving in depends on the\nbalance of friction\/drag and Coriolis force. On average, the water moves to\nthe right of the wind in the northern hemisphere; if the wind is blowing\nnorthward, the water moves eastward.\n\nNow imagine you have strong wind blowing northward at one location and weaker\nwind to the right of it. The water at the first location moves to the right,\nand it does so faster than the water at the second location (because the wind\nforcing the water is stronger at the first location). The water converges at\nthe second location, pushing the water downward. This is how the curl of the\nwind stress (the northward wind changing in the east-west direction) is\nrelated to the water convergence (the eastward current changing in the east-\nwest direction) and hence to water being pushed down or pulled up. Positive\nwind stress curl pulls water up; negative wind stress curl pushes it down.\n\nThe last relevant part here is that this kind of motion suppresses ocean\nmixing. The relevant sentence from that paper is\n\n> The wind stress curl and hence Ekman pumping anomalies were negative, which\n> also is consistent with relatively weak entrainment.\n\n\"Entrainment\" is how much of the deep, cold ocean water mixes with the\nrelatively warm upper ocean water, cooling it. The negative wind stress curl\nleads to water being pushed down and less deep water mixing with the upper\nocean. The upper ocean stayed warmer, so the whole heat blob lasted longer."}
{"query":"I read that the acidic character, or, better, persilicic character of a rock is determined by a content of more than 65% SiO2\r\n.\r\n\r\nA rock is defined, by the texts available to me, as mesosilicic (or intermediate) when its SiO2\r\n content is contained in the interval 52%\u221265%\r\n, while it is called hyposilicic (or basic) when SiO2<52%\r\n.\r\n\r\nIf I correctly understand the SiO2\r\n contained in the rock as a part of a mineral other than pure SiO2\r\n, for example, the Si2O4\r\n part of anorthite CaAl2Si2O8\r\n, is calculated into the quantity of total silica. What I cannot understand at all, is whether mass or volume is taken into account.","reasoning":"The website from Tulane University provides a general classification of igneous rocks based on their silica (SiO2) content. According to the classification:\r\n\r\n- Rocks with a silica content above 66 wt. % are classified as \"acid.\"\r\n- Rocks with a silica content ranging from 52 to 66 wt. % are classified as \"intermediate.\"\r\n- Rocks with a silica content ranging from 45 to 52 wt. % are classified as \"basic.\"\r\n- Rocks with a silica content below 45 wt. % are classified as \"ultrabasic.\"","id":"71","excluded_ids":["N\/A"],"gold_ids_long":["acidity_of_rock\/igrockclassif_htm.txt"],"gold_ids":["acidity_of_rock\/igrockclassif_htm2.txt","acidity_of_rock\/igrockclassif_htm3.txt","acidity_of_rock\/igrockclassif_htm5.txt","acidity_of_rock\/igrockclassif_htm1.txt","acidity_of_rock\/igrockclassif_htm4.txt"],"gold_answer":"$\\begingroup$\n\nAccording the website [\nhttp:\/\/www.tulane.edu\/~sanelson\/eens212\/igrockclassif.htm\n](http:\/\/www.tulane.edu\/~sanelson\/eens212\/igrockclassif.htm) from Tulane\nUniversity silica content in igneous rock is based on mass. Below is copy of\nthe relevant part of the web page where it states **wt %** , weight percent.\n\nGeneral Chemical Classifications\n\n$\\ce{SiO2}$ (Silica) Content\n\n    \n    \n    > 66 wt. % - Acid\n    \n    52-66 wt% - Intermediate\n    \n    45-52 wt% - Basic\n    \n    < 45 wt % - Ultrabasic"}
{"query":"Taiga is the Russian word for big areas of forest wilderness in high latitude regions. What about forests in the mountains? What is the name for the forested areas in mountains which are below the treeline?","reasoning":"Forests directly below the alpine tree line are high-elevation or Montane forests.","id":"72","excluded_ids":["N\/A"],"gold_ids_long":["below_treeline\/Montane_ecosystems.txt","below_treeline\/Tree_line.txt"],"gold_ids":["below_treeline\/Tree_line2.txt","below_treeline\/Tree_line5.txt","below_treeline\/Tree_line3.txt","below_treeline\/Montane_ecosystems4.txt"],"gold_answer":"$\\begingroup$\n\nForests directly below the [ alpine tree line\n](https:\/\/en.wikipedia.org\/wiki\/Tree_line#Alpine) are high-elevation or\nMontane forests. See more about [ Montane ecology here\n](https:\/\/en.wikipedia.org\/wiki\/Montane_ecology) .\n\n[ ![treeline image](https:\/\/i.sstatic.net\/9AjVQ.jpg)\n](https:\/\/i.sstatic.net\/9AjVQ.jpg) Image from [\nhttp:\/\/www.nature.com\/scitable\/knowledge\/library\/global-treeline-\nposition-15897370 ](http:\/\/www.nature.com\/scitable\/knowledge\/library\/global-\ntreeline-position-15897370)"}
{"query":"I have downloaded the sea surface temperature data from the Ocean Color website, the file is in NetCDF format and contains no of geophysical_data variables like sst, qual_sst, flag_sst, bias_sst, etc. I used the following MATLAB code for file read and it is giving me an error:\n\ntemp=ncread('A2014213085500.L2_LAC_SST.x.nc','sst') \nError:\n\nError using internal.matlab.imagesci.nc\/getGroupAndVarid (line 2075)\nCould not find variable or group 'sst' in file.\n\nError in internal.matlab.imagesci.nc\/read (line 593)\n        [gid, varid] = getGroupAndVarid(this, location);\n\nError in ncread (line 58)\nvardata = ncObj.read(varName, varargin{:});\nCan someone tell me what is the cause of the error?","reasoning":"use ncgeodataset can read a netCD4 file in Matlab.","id":"73","excluded_ids":["N\/A"],"gold_ids_long":["cd4_file\/ncgeodataset_wiki.txt"],"gold_ids":["cd4_file\/ncgeodataset_wiki1.txt","cd4_file\/ncgeodataset_wiki4.txt","cd4_file\/ncgeodataset_wiki3.txt","cd4_file\/ncgeodataset_wiki5.txt","cd4_file\/ncgeodataset_wiki2.txt"],"gold_answer":"$\\begingroup$\n\nThese days I use: [ ncgeodataset\n](https:\/\/code.google.com\/p\/nctoolbox\/wiki\/ncgeodataset) . The routine allows\nfor the extraction of a subset of data without having to load the entire file\nor even an array into Matlab. It is great for large datasets."}
{"query":"In ocean spectra such as the Pierson Moskowitz or the JONSWAP models, the units of S(\u03c9)\n are m2\/(rad\/s)\n (or whatever unit of measurement you are working in). Where does the m2\n come from and what does it mean physically?\nI understand that the integral of the spectrum over all frequencies, i.e. \u222bS(\u03c9)d\u03c9\n, is the variance which means that the integral should have m2\n units? Please correct me if I am wrong.","reasoning":"the units of S(w) is m^2, which comes from integral of \u222bS(\u03c9)d\u03c9","id":"74","excluded_ids":["N\/A"],"gold_ids_long":["unit_of_wave_spectrum\/4522.txt"],"gold_ids":["unit_of_wave_spectrum\/45223.txt","unit_of_wave_spectrum\/45222.txt"],"gold_answer":"$\\begingroup$\n\n> I understand that the integral of the spectrum over all frequencies is the\n> variance which means that the integral should have $m^2$ units? Please\n> correct me if I am wrong.\n\nYou are correct. If elevation $\\eta(t)$ is the measured quantity (units of\n$m$), the Fourier transform of wave variance $\\eta^2$ yields spectrum $S(f)$\nwith the units of $m^2\/Hz$, or if you are working with angular frequency\n$\\omega = 2\\pi f$, it yields $S(\\omega)$ with the units of $m^2\/rad\/Hz$.\n\nMore details can be found in the answer to [ this question\n](https:\/\/earthscience.stackexchange.com\/questions\/4521\/is-wave-spectrum-\nalways-positive-and-why\/4522) ."}
{"query":"I'm trying to solve the following problem. The sea level in the past was 200 m higher than today. The seawater became in isostatic equilibrium with the ocean basin. what is the increase in the depth x\r\n of the ocean basins? Water density is \u03c1w=1000 kg m\u22123\r\n, and mantle density is 3300 kg m\u22123\r\n.\r\n\r\nUsing the compensation column, I reach:\r\n\r\nx=(\u03c1w\u2217200 m)\/3300=60.60 m\r\nbut normally I expected to find 290 m.\r\n\r\nCan someone explain to me what's wrong?","reasoning":"by making use of Airy's isostasy model, we can calculate hydrostatic equilibrium in the situation when sea level being 200m higher and in isostatic equilibrium.","id":"75","excluded_ids":["N\/A"],"gold_ids_long":["hydrostatic_equilibrium\/Isostasy.txt"],"gold_ids":["hydrostatic_equilibrium\/Isostasy2.txt","hydrostatic_equilibrium\/Isostasy4.txt","hydrostatic_equilibrium\/Isostasy5.txt","hydrostatic_equilibrium\/Isostasy3.txt"],"gold_answer":"$\\begingroup$\n\nI am assuming you are asking for the case of sea level being 200m higher\n**and** in isostatic equilibrium. In that case we can make use of Airy's\nisostasy model: [ https:\/\/en.wikipedia.org\/wiki\/Isostasy#Airy\n](https:\/\/en.wikipedia.org\/wiki\/Isostasy#Airy)\n\nApplied to a water column over the mantle, you have to replace $\\rho_c$ with\nyour $\\rho_w$. The total increase in ocean depth is $x = b_1 + h_1$, where\n$h_1$ are the 200 m extra sea level and $b_1$ is the depth increase to\nisostasy. Using the equation given in the link: $$ x = \\frac{h_1\n\\rho_w}{\\rho_m - \\rho_w} + h_1, $$\n\ngiving $x =$ 287 m"}
{"query":"I am following the paper to calculate UTCI using ERA5 meteorological variables.\r\n\r\nhttps:\/\/link.springer.com\/article\/10.1007\/s00484-020-01900-5?shared-article-renderer\r\n\r\nIn the paper, the authors have mentioned that they are using ERA5 product. And specifically mentioned to use the direct and diffuse component of shortwave (SW) radiation.\r\n\r\nThe problem is, ERA5 data does not provide the direct and diffuse SW separately. Rather it only provides Surface solar radiation downwards which includes both the direct and diffuse component.\r\n\r\nMy question would be, is there a way to calculate the direct and diffuse component of SW from ERA5. The dataset I have is similar to ERA5 and has the Downward SW and Net SW. I have no problem in obtaining the Long waves BTW.\r\n\r\nAny help would be much appreciated. TIA","reasoning":"A clearness index approximation can be used to partition direct and diffuse from ERA-Interim. ","id":"76","excluded_ids":["N\/A"],"gold_ids_long":["ears\/topo_scale.txt"],"gold_ids":["ears\/topo_scale4.txt","ears\/topo_scale5.txt","ears\/topo_scale1.txt"],"gold_answer":"$\\begingroup$\n\n[ This paper\n](https:\/\/gmd.copernicus.org\/articles\/7\/387\/2014\/gmd-7-387-2014.pdf) By Fiddes\n& Gruber ( _TopoSCALE: downscaling gridded climate data in complex terrain_ )\nprovides a method to partition direct and diffuse from ERA-Interim. The\nresults could easily be applied to ERA5.\n\nIt uses a clearness index approximation from Ruiz-Arias et al. (2010)\n\n$k_t = SW \/ SW_{toa}$  (eq C11) where  $ SW_{toa} $  is the shortwave at the\ntop-of-atmosphere.\n\nthen,\n\n$SW_{diffuse} = 0.952 - 1.041 e^{-exp(2.3 - 4.702k_t)}$  (eq C12)\n\nYou should be able to get top-of-atmosphere SW from ERA5, or possibly\ncalculate it based on solar geometry."}
{"query":"Given the fact that industries emit about 1.5 billion metric tons of carbon dioxide each year just in the US, why is it still such a small part of the atmosphere's composition (0.04%)?","reasoning":"The mass of the atmosphere is 5.1 \u00d7 1018 kg, which is 5.1 \u00d7 1015 t. As stated in the edited question, industries emits 1.5 billion metric tons of carbon dioxide each year, that's 1.5 \u00d7 109 t, which is super small compared to the whole.","id":"77","excluded_ids":["N\/A"],"gold_ids_long":["co2_abundance\/earthfact_html.txt"],"gold_ids":["co2_abundance\/earthfact_html4.txt","co2_abundance\/earthfact_html5.txt","co2_abundance\/earthfact_html3.txt"],"gold_answer":"$\\begingroup$\n\nThe [ mass of the atmosphere\n](https:\/\/nssdc.gsfc.nasa.gov\/planetary\/factsheet\/earthfact.html) is 5.1 \u00d7 10\n18  kg, which is 5.1 \u00d7 10  15  t.\n\nAs stated in the edited question,\n\n> industries emits 1.5 billion metric tons of carbon dioxide each year,\n\nThat's 1.5 \u00d7 10  9  t.\n\nThe mass of Earth's atmosphere is 3,400,000 times the mass of CO  2  that\nindustries produces each year in the US."}
{"query":"The question is clear enough in my opinion but, I've found out that if you redraw this picture, you'll notice that the Sun is as big as the Earth. But if you scale up the Sun to it's real size compared to the Earth, you would realize that the Earth would covered in daylight ALL THE TIME. So what's going on here?","reasoning":"The reason why the 'total daytime' will never happen is that, the sun is super farwaway from the earth, the light thus become almost parallel, which will not 'cover' the earth's surface.","id":"78","excluded_ids":["N\/A"],"gold_ids_long":["always_daytime\/Astronomical_unit.txt","always_daytime\/what_makes_suns_light_travel_as_parallel_beams_towards_earth.txt"],"gold_ids":["always_daytime\/Astronomical_unit2.txt","always_daytime\/what_makes_suns_light_travel_as_parallel_beams_towards_earth3.txt","always_daytime\/what_makes_suns_light_travel_as_parallel_beams_towards_earth4.txt","always_daytime\/what_makes_suns_light_travel_as_parallel_beams_towards_earth1.txt","always_daytime\/what_makes_suns_light_travel_as_parallel_beams_towards_earth2.txt","always_daytime\/Astronomical_unit3.txt","always_daytime\/Astronomical_unit4.txt"],"gold_answer":"$\\begingroup$\n\nThe sun is [ really far away\n](https:\/\/en.wikipedia.org\/wiki\/Astronomical_unit) . Thus its rays are [\nessentially parallel\n](https:\/\/physics.stackexchange.com\/questions\/155075\/what-makes-suns-light-\ntravel-as-parallel-beams-towards-earth) at the earth's orbit. So, while the\ndiagram you posted is clearly a bit off in terms of the relative size and\ndistance between the sun and the earth, the parallel rays are about right.\n\n[ ![Sun and Earth - public domain image](https:\/\/i.sstatic.net\/L4pXa.png)\n](https:\/\/i.sstatic.net\/L4pXa.png)"}
{"query":"Natural gas:\n\n...is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxide, nitrogen, hydrogen sulfide, or helium.\n\nI saw the graphic below in the BBC News article Trump climate: Challenges loom after Obama policies scrapped. It lists natural gas as the source of about 33% of the US electricity generation in 2015, but also lists \"Other gases\" as the source of less than 1%. Presumably it is a meaningful fraction of that 1% or else the BBC would not have included it. While the source of the data is listed as the US Energy Information Agency, the graphic itself was prepared by the BBC if I understand correctly.\n\nAre thee other gases available from the Earth that could account for this fraction of 1%? I don't mean gases that are produced during an industrial refinement process, but perhaps gases that were simply separated. Just for example could it be natural propane? The same Wikipedia article mentions heavier hydrocarbons, but I don't understand if these are already present in the Earth and just being separated, or if they are produced primarily as reaction products.","reasoning":"By retrive the data from US resources, the 'other gases' accounts more than 1%","id":"79","excluded_ids":["N\/A"],"gold_ids_long":["other_gases\/faq.txt","other_gases\/us_energy_facts.txt","other_gases\/epa.txt"],"gold_ids":["other_gases\/faq5.txt","other_gases\/epa3.txt"],"gold_answer":"$\\begingroup$\n\nThe category \"other gases\" may not solely include other naturally occurring\ngases extracted from the Earth.\n\nAs you state [ natural gas ](https:\/\/en.wikipedia.org\/wiki\/Natural_gas) is\npredominantly methane, extracted from the Earth.\n\nAnother type of gas commonly used is [ petroleum gas\n](https:\/\/en.wikipedia.org\/wiki\/Liquefied_petroleum_gas) , which is prepared\nby refining petroleum of wet natural gas. Petroleum gas is [ propane\n](https:\/\/en.wikipedia.org\/wiki\/Propane) or [ butane\n](https:\/\/en.wikipedia.org\/wiki\/Butane) .\n\n[ Coal gas ](https:\/\/en.wikipedia.org\/wiki\/Coal_gas) , which was manufactured\nfrom coal and largely consists of hydrogen, carbon monoxide and methane, is no\nlonger manufactured or used.\n\nAnother type of gas that could be included in the category is [ biogas\n](https:\/\/en.wikipedia.org\/wiki\/Biogas) , which is a manufactured gas made\nfrom biological waste products, such as: manure, sewage, food waste and green\nwaste. Biogas is predominantly methane."}
{"query":"What is a temperature inversion and can it trap smog\/pollution?\r\nJust as the title says, I heard about this term but am not sure how it works.","reasoning":" A temperature inversion is where the air temperature rises with altitude. Since pollution is generally produced at ground level, temperature inversions can trap the pollution (e.g. smog) at ground level.","id":"80","excluded_ids":["N\/A"],"gold_ids_long":["temperature_inversion\/Lapse_rate.txt","temperature_inversion\/Inversion_(meteorology).txt"],"gold_ids":["temperature_inversion\/Inversion_(meteorology)5.txt","temperature_inversion\/Inversion_(meteorology)4.txt","temperature_inversion\/Lapse_rate2.txt","temperature_inversion\/Lapse_rate3.txt","temperature_inversion\/Lapse_rate4.txt","temperature_inversion\/Lapse_rate5.txt"],"gold_answer":"$\\begingroup$\n\nNormally, temperature broadly [ decreases with altitude\n](https:\/\/en.wikipedia.org\/wiki\/Lapse_rate) , and convection is effective:\nlocally warmer air will rise, and cooler air will fall. A [ temperature\ninversion ](https:\/\/en.wikipedia.org\/wiki\/Inversion_\\(meteorology\\)) is where\nthe air temperature **rises** with altitude. This means that convection is\nless effective because the air above is already warmer, and so there is less\nmixing of air between altitudes.\n\nSince pollution is generally produced at ground level, temperature inversions\ncan trap the pollution (e.g. smog) at ground level."}
{"query":"In meteorology the seasons always start at the beginning of the month the astronomical seasons start.\nThe astronomical seasons start around the 21st in a month so I guess it would make more sense to start the meteorological season at the first day of the month following the start of the astronomical season.\nAnother more logical reason to do this: for example the meteorological winter start at December 1 and ends at February 28 (or 29) in the next year so meteorology actually measures in broken years. Should the meteorological winter start at January 1 and end at March 31 then all seasons do exactly fit in the same year.\nSo is there a reason why meteorologists do it this way or is it just arbitrarily chosen?","reasoning":"Meteorological seasons are based on temperature, whereas astronomical seasons are based on the position of the earth in relation to the sun. So meteorological winter is the three coldest months of the year (December, January, and February) and meteorological summer is the three warmest months of the year (June, July, and August).","id":"81","excluded_ids":["N\/A"],"gold_ids_long":["meteorological_versus_astronomical_seasons\/meteorological_versus_astronomical_seasons.txt"],"gold_ids":["meteorological_versus_astronomical_seasons\/meteorological_versus_astronomical_seasons3.txt"],"gold_answer":"$\\begingroup$\n\nMeteorological seasons are based on temperature, whereas astronomical seasons\nare based on the position of the earth in relation to the sun. So\nmeteorological winter is the three coldest months of the year (December,\nJanuary, and February) and meteorological summer is the three warmest months\nof the year (June, July, and August). More information can be found on this [\nNOAA web site ](https:\/\/www.ncei.noaa.gov\/news\/meteorological-versus-\nastronomical-seasons) ."}
{"query":"I'm slightly confused by how thermohaline circulation works in the Earth's oceans. Is it different for surface water as opposed to deep water? I thought that warm water from the equator is transported to the poles, cools down, and then returns to lower latitudes. Is my thinking incorrect? Isn't water denser near the equator because of higher salinity? How does this impact the ocean circulation?","reasoning":"Salinity and temperature affect the density of seawater. Cooling water with fixed salinity makes it heavier and sink, while removing water through evaporation or ice formation increases salinity and density. This process, known as thermohaline circulation, causes surface water in the tropics to become saline but less dense due to high temperatures, while in colder climates, the water cools down and the high salinity causes it to sink. In polar regions, ice formation increases the density of surface water by leaving salt behind in the sea.","id":"82","excluded_ids":["N\/A"],"gold_ids_long":["thermohaline_circulation\/ocean_conveyor_belt_htm.txt","thermohaline_circulation\/05conveyor1_html.txt"],"gold_ids":["thermohaline_circulation\/ocean_conveyor_belt_htm5.txt","thermohaline_circulation\/05conveyor1_html3.txt"],"gold_answer":"$\\begingroup$\n\nSalinity and temperature both affects the density of sea water. When water\nwith a fixed salinity cools down, it becomes heavier and sinks. In the same\nway, when vapor or ice removes water from sea water, the remains is more\nsaline and heavier. Thermohaline circulation can work as you describe. Surface\nwater in the tropics is saline, due to evaporation, but warm due to high\ntemperature in the atmosphere and therefor low density. As it reach colder\nclimate (less solar energy per area), it cools down and the high salinity\nmakes it sink. Surface water in polar regions also get heavier as ice is\nformed of water and leave the salt behind in the sea.\n\nThis is very simplified model, you can read more on the topic [ here\n](http:\/\/oceanmotion.org\/html\/background\/ocean-conveyor-belt.htm) and [ here\n](http:\/\/oceanservice.noaa.gov\/education\/tutorial_currents\/05conveyor1.html) ."}
{"query":"Where do I find the documentation of different VARIANT-IDs for the CMIP6 dataset? A VARIANT-ID is of the format r<k>i<l>p<m>f<n>, where the characters r, i, p and f denote:\n\nr-realisation\ni-initialisation method\np-physics\nf-forcing\n\nI checked the overview paper Eyring et al. (2016), but it doesn't mention anything about VARIANT-ID. I have also checked other documents provided at ESGF, but couldn't find any information.","reasoning":"The variant_labels are defined in the CMIP6 Data Reference Syntax (DRS) document and are made up of the realization_index, initialization_index, physics_index and forcing_index.\r\n\r\nA link to this DRS document can for example be found in the CMIP6 Participation Guide for Modelers.","id":"83","excluded_ids":["N\/A"],"gold_ids_long":["VARIANT_IDs_in_CMIP6\/google_cmip6.txt","VARIANT_IDs_in_CMIP6\/modelers_html.txt"],"gold_ids":["VARIANT_IDs_in_CMIP6\/google_cmip62.txt","VARIANT_IDs_in_CMIP6\/google_cmip63.txt","VARIANT_IDs_in_CMIP6\/google_cmip64.txt","VARIANT_IDs_in_CMIP6\/google_cmip65.txt","VARIANT_IDs_in_CMIP6\/modelers_html3.txt","VARIANT_IDs_in_CMIP6\/google_cmip61.txt","VARIANT_IDs_in_CMIP6\/modelers_html5.txt","VARIANT_IDs_in_CMIP6\/modelers_html4.txt","VARIANT_IDs_in_CMIP6\/modelers_html2.txt"],"gold_answer":"$\\begingroup$\n\nThe variant_labels are defined in the [ CMIP6 Data Reference Syntax (DRS)\n](https:\/\/docs.google.com\/document\/d\/1h0r8RZr_f3-8egBMMh7aqLwy3snpD6_MrDz1q8n5XUk\/edit)\ndocument and are made up of the realization_index, initialization_index,\nphysics_index and forcing_index.\n\nA link to this DRS document can for example be found in the [ CMIP6\nParticipation Guide for Modelers\n](https:\/\/pcmdi.llnl.gov\/CMIP6\/Guide\/modelers.html) .\n\nEdit: Following up Deditos' comment, I quote the respective section of the DRS\ndocument below:\n\n> For a given experiment, the realization_index, initialization_index,\n> physics_index, and forcing_index are used to uniquely identify each\n> simulation of an ensemble of runs contributed by a single model. These\n> indices are defined as follows:\n\n>   * realization_index = an integer (\u22651) distinguishing among members of an\n> ensemble of simulations that differ only in their initial conditions (e.g.,\n> initialized from different points in a control run). Note that if two\n> different simulations were started from the same initial conditions, the\n> same realization number should be used for both simulations. For example if\n> a historical run with \u201cnatural forcing\u201d only and another historical run that\n> includes anthropogenic forcing were both spawned at the same point in a\n> control run, both should be assigned the same realization. Also, each so-\n> called RCP (future scenario) simulation should normally be assigned the same\n> realization integer as the historical run from which it was initiated. This\n> will allow users to easily splice together the appropriate historical and\n> future runs.\n>   * initialization_index = an integer (\u22651), which should be assigned a value\n> of 1 except to distinguish simulations performed under the same conditions\n> but with different initialization procedures. In CMIP6 this index should\n> invariably be assigned the value \u201c1\u201d except for some hindcast and forecast\n> experiments called for by the DCPP activity. The initialization_index can be\n> used either to distinguish between different algorithms used to impose\n> initial conditions on a forecast or to distinguish between different\n> observational datasets used to initialize a forecast.\n>   * physics_index = an integer (\u22651) identifying the physics version used by\n> the model. In the usual case of a single physics version of a model, this\n> argument should normally be assigned the value 1, but it is essential that a\n> consistent assignment of physics_index be used across all simulations\n> performed by a particular model. Use of \u201cphysics_index\u201d is reserved for\n> closely-related model versions (e.g., as in a \u201cperturbed physics\u201d ensemble)\n> or for the same model run with slightly different parameterizations (e.g.,\n> of cloud physics). Model versions that are substantially different from one\n> another should be given a different source_id\u201d (rather than simply assigning\n> a different value of the physics_index).\n>   * forcing_index = an integer (\u22651) used to distinguish runs conforming to\n> the protocol of a single CMIP6 experiment, but with different variants of\n> forcing applied. One can, for example, distinguish between two historical\n> simulations, one forced with the CMIP6-recommended forcing data sets and\n> another forced by a different dataset, which might yield information about\n> how forcing uncertainty affects the simulation.\n>\n\n> Each data provider can assign whatever positive integers they like for the\n> realization_index, intialization_index, physics_index, and forcing index.\n> For each source\/experiment pair, however, consistency (in these indices)\n> should be maintained across each parent\/child pair whenever sensible (so\n> that, for example, both the ScenarioMIP child and its \u201chistorical\u201d parent\n> simulation would be assigned the same set of index values for realization,\n> initialization, and physics); the integer 1 should normally be chosen for\n> each of these in the case of a single variant or for the primary variant (if\n> there is one). This is only a suggestion, however; there should be no\n> expectation on the part of users that every model will have a value of 1\n> assigned to any of the r, i, p, f indices, and even if a 1 is assigned it\n> does not imply that it is the primary variant. Note also that a child\n> spawned by a control run will not necessarily have the same \u201cripf\u201d value as\n> the control, since, for example, multiple realizations of an experiment will\n> branch from the same control.\n>\n> Note that none of the \u201cripf\u201d indices can be omitted.\n>\n> Example of a variant_label: if realization_index=2, initialization_index=1,\n> physics_index=3, and forcing_index=233, then variant_label = \u201cr2i1p3f233\u201d."}
{"query":"Has anyone ever found or gone looking for similar locations, i.e. volcanic eruption sites in which unfortunate victims \u2013 human and non-human \u2013 have been entombed in the volcanic ash, with the possibility of revealing their forms by producing casts from the voids? Such sites, if they exist, could reveal exciting new knowledge about ancient peoples and animals.","reasoning":"Volcanic eruption sites have been explored to uncover preserved victims entombed in volcanic ash, offering insights into ancient peoples and animals. The 1902 eruption of Mt. Pel\u00e9e in Martinique, which claimed 30,000 lives, is a well-known example, though the extent of burial and preservation varies.","id":"84","excluded_ids":["N\/A"],"gold_ids_long":["pompeii_and_herculaneum\/Mount_Pel_C3_A9e.txt"],"gold_ids":["pompeii_and_herculaneum\/Mount_Pel_C3_A9e4.txt"],"gold_answer":"$\\begingroup$\n\nProbably the best known is more recent, the 1902 eruption of [ Mt. Pel\u00e9e on\nMartinique ](https:\/\/en.wikipedia.org\/wiki\/Mount_Pel%C3%A9e) , where 30,000\npeople were killed by pyroclastic flows. I don't know the extent of burial -\nit appears that the city may have been destroyed more by the ash cloud than\nthe dense part of the flow."}
{"query":"For my research related to coastal Odisha, India I am mapping the coastal boundary. I have downloaded available Landsat images which date back to 1972. But I want to map the same for before 1972.\r\n\r\nI am interested in old topographic maps showing the coastal boundary of Odisha, preferably before 1970.\r\n\r\nDoes anyone know from where can I get the scanned map of the same?","reasoning":"The old topographic maps can be found at a Texas-Austin's website, especially India's","id":"85","excluded_ids":["N\/A"],"gold_ids_long":["old_topographic_map\/index_html.txt","old_topographic_map\/india.txt"],"gold_ids":["old_topographic_map\/index_html5.txt","old_topographic_map\/india5.txt","old_topographic_map\/india3.txt","old_topographic_map\/index_html4.txt","old_topographic_map\/india4.txt","old_topographic_map\/index_html3.txt","old_topographic_map\/india1.txt"],"gold_answer":"$\\begingroup$\n\nThe [ PCL Map Collection ](https:\/\/maps.lib.utexas.edu\/maps\/index.html)\n(University of Texas at Austin) is a huge online collection of maps. For\nIndia, they have [ a series from the U.S. Army Map Service\n](https:\/\/maps.lib.utexas.edu\/maps\/ams\/india\/) which might be of interest, as\nit dates from the 50's and has a decent scale (1:250,000). They also have\nolder maps from the British era, but the series doesn't seem to be complete.\nIt might be worth looking for those at the Royal Geographical Society\narchives."}
{"query":"Atmospheric mixing ratios of the hydroxyl radical have relatively short lifespans (on the order of microseconds). When modeling air quality or the weather, the time step is usually much larger than the the half life of hydroxyl. How is this computation numerically stable? Is the problem of numerical stability simply ignored?","reasoning":"air quality models like CMAQ assume a pseudo-steady-state for the hydroxyl radical (OH) due to its catalytic nature and rapid reactions. This simplification is made to ensure numerical stability, as explicitly modeling OH can be challenging. For more detailed OH chemistry, specialized box models like MECCA are typically employed.","id":"86","excluded_ids":["N\/A"],"gold_ids_long":["hydroxyl_radical_chemistry\/AQCHEM_NOTES_txt.txt"],"gold_ids":["hydroxyl_radical_chemistry\/AQCHEM_NOTES_txt3.txt","hydroxyl_radical_chemistry\/AQCHEM_NOTES_txt4.txt","hydroxyl_radical_chemistry\/AQCHEM_NOTES_txt1.txt","hydroxyl_radical_chemistry\/AQCHEM_NOTES_txt2.txt","hydroxyl_radical_chemistry\/AQCHEM_NOTES_txt5.txt"],"gold_answer":"$\\begingroup$\n\nThe hydroxyl radical chemistry is not modeled explicitly in air quality\nmodels, so numerical stability is not an issue. Instead, OH is held in pseudo-\nsteady-state. For instance, see [ CMAQ's documentation\n](https:\/\/www.cmascenter.org\/cmaq\/documentation\/4.7.1\/AQCHEM_NOTES.txt) which\nstates:\n\n> In CMAQ's gas phase, OH is assumed to be in pseudo-steady state, and it is\n> not a transported species. This is because hydroxyl radical reactions tend\n> to be catalytic (e.g., consumption and production). In the aqueous phase\n> chemistry, OH is absorbed by cloud water and in an open cloud model (i.e.,\n> the design approach currently employed), absorbed species (e.g., OH) would\n> be replenished via gas-to-cloud partitioning. However, due to operator\n> splitting, aqueous and gas-phase chemistry are not solved simultaneously. To\n> account for this and other uncertainties in predicted OH aqueous phase\n> concentrations (e.g., neglect of production reactions (H2O2 + hv -> 2 OH)\n> not currently implemented in aqchem), a steady-state assumption for OH is\n> adopted in the aqueous chemistry routine.\n\nTypically, if you are trying to model something like the hydroxyl radical, you\nwould use a [ box-model like MECCA ](http:\/\/www.atmos-chem-\nphys.net\/10\/9705\/2010\/) , not a chemical transport model."}
{"query":"The image below is included in the BBC article Amazing white rainbow snapped over Scottish moor. Apparently this phenomenon is sometimes called a \"fog-bow\" and is characterized by the washing out of perceived color relative to a conventional rainbow.\r\nIs this related to the geometry (fog being far closer to the viewer) or properties of the droplets themselves? If so, which properties and why?","reasoning":"Fog bows lack color compared to rainbows because the tiny water droplets in fog (less than 0.05 mm diameter) cause diffraction effects that smear out the colors, unlike the larger droplets in rainbows.","id":"87","excluded_ids":["N\/A"],"gold_ids_long":["fog_bow\/Fog_bow.txt"],"gold_ids":["fog_bow\/Fog_bow5.txt"],"gold_answer":"$\\begingroup$\n\nThe reason why [ fog bows ](https:\/\/en.wikipedia.org\/wiki\/Fog_bow) lack\ncolour, compared to rainbows, is due to the size of the drops of water.\n\nFog is composed of very small drops of water - less than 0.05 mm diameter.\nBecause of this the wavelength of light is critical, with diffraction smearing\nout colours that the larger drops of water in a rainbow would make."}
{"query":"I have recently bought a medium sized plot of wood\/scrub land. Half of this plot was once used to dump shale from coal mines, which means I have a lot of shale.\r\n\r\nI have been wondering\/looking for possible uses for the stuff. One thought I've had is to make \"mud bricks\" however I can't find any mention of whether it is possible or not. I know the traditional method uses loamy soil but would it work with shale?\r\n\r\nI don't have a kiln or any way of baking the bricks, so would be reliant on the sun. I was thinking maybe adding water and maybe some loam?\r\n\r\nAside: there are no suitable tags for my question and I do not have the reputation to add any, I'm thinking I could be on the wrong site for this question, if I am, please advise me of a more suitable one.","reasoning":"shale can be used to make sun-dried mud bricks. Being a type of mudstone composed of clay and silt, shale can be crushed and mixed with water, potentially with some added loam, to produce an effective material for making simple unfired mud bricks.","id":"88","excluded_ids":["N\/A"],"gold_ids_long":["shale\/shale_shtml.txt"],"gold_ids":["shale\/shale_shtml3.txt","shale\/shale_shtml2.txt","shale\/shale_shtml4.txt","shale\/shale_shtml1.txt"],"gold_answer":"$\\begingroup$\n\nYour idea has merit. Shale is classified by geologists as being a mudstone. It\nis composed of silt and clay sized minerals.\n\nAccording to this [ geology website ](http:\/\/geology.com\/rocks\/shale.shtml) ,\nshales can be crushed to produce a clay and then mixed with water. These days,\nitems that were once made from natural clay, such as terracotta pots and tiles\nfor roofs, are now made from crushed shale.\n\n* * *\n\nExtra Information\n\nOne thing to be mindful of is that clays expand when wet and contract when\ndry. Anything you make from it, such as bricks, that isn't baked or protected\nfrom water by a sealed coating will expand and contract according to it\nmoisture content.\n\nAnother application which you may want to consider is to supply crushed shale\nas a garden mulch or other such landscaping product."}
{"query":"I was wondering if we could possibly reduce the severity of, or steer a hurricane by changing albedo (e.g. dying the part ocean with a temporary light colored dye)? My thought would be to put this dye well in front of the path of a hurricane, with enough time to reflect the sunlight back off the ocean and cool the ocean surface. When the hurricane arrives there, the ocean surface should then be cooler, leading to the hurricane being less powerful. I am also wondering if this could be used to steer the hurricane somehow (e.g. if a hurricane would be drawn to or repelled away from cool ocean surface). If so, could we use that to steer a hurricane away from populated areas?\r\n\r\nSome potential methods (there may be others):\r\n\r\nUse light colored dye injected into the ocean\r\n\r\nUse light colored smoke to block the sun from reaching the ocean\r\n\r\nPossibly use \"cloud seeding\" ahead of the hurricane and form clouds to block the sun light from warming the ocean. - Covered in the alternate question\r\n\r\nPerhaps a \"surface film\" could also be applied temporarily to part of the ocean (sort of like a \"light colored oil spill\", hopefully with something safer for the environment than oil). - Covered in the alternate question\r\n\r\nIf this experiment were to be conducted, I would think it should be done far from inhabited land. Environmental impacts would need to be thought out too, e.g. would a film block the carbon dioxide \/ oxygen exchange in that area and cause severe environmental impact? Could the experiment actually strengthen instead of weaken a hurricane?","reasoning":"Changing the ocean's albedo (reflectivity) just before a hurricane passes is unlikely to have a significant cooling effect due to water's high heat capacity and the short timeframe. More promising approaches being explored include pumping up cold water from deeper ocean layers to cool the surface, or injecting aerosols into the atmosphere to reflect sunlight and encourage rainfall, though these methods have challenges and potential side effects that need further study.","id":"89","excluded_ids":["N\/A"],"gold_ids_long":["reflecting_sunlights\/usgs.txt","reflecting_sunlights\/news.txt"],"gold_ids":["reflecting_sunlights\/usgs3.txt","reflecting_sunlights\/news1.txt"],"gold_answer":"$\\begingroup$\n\nWater has a large [ thermal capacity ](https:\/\/water.usgs.gov\/edu\/heat-\ncapacity.html) .\n\n> which is why the temperature change between seasons is gradual rather than\n> sudden, especially near the oceans.\n\nFor water to lose heat time is required. By changing the albedo of the ocean\njust prior to a hurricane\/cyclone\/typhoon passing over a section of water will\nnot give the water enough time to cool down to have any significant effect.\n\nIf it were possible to change the temperature of water to minimize the\nstrength of hurricanes\/typhoons\/cyclones, large sections of ocean would need\nto have their albedos changed for a long period of time.\n\n* * *\n\nEdit 10 August 2023\n\n[ Newly discovered information\n](https:\/\/www.abc.net.au\/news\/2023-08-10\/cyclone-risks-of-controlling-weather-\nhurricane-typhoon\/102706094) reveals that hurricanes could be influence by\nother means - cooling the surface reaches of a region on ocean by pumping cold\nwater from at least 200 m below the ocean surface.\n\n> there's been renewed interest in Cold War era experiments in weather\n> control. While early efforts had little success, our new research evaluates\n> other methods of weakening these storms by pumping up cold water from the\n> depths or spreading particles in the lower atmosphere to reduce incoming\n> heat and encourage early rainfall.\n>\n> In the 1960s, the United States explored the use of cloud seeding to stop\n> hurricanes from forming.\n>\n> During Project STORMFURY, planes flew high above cyclones out at sea and\n> sprayed them with silver iodide, a chemical which could encourage water\n> droplets to clump together and fall as rain. This, the theory ran, would\n> disrupt the hurricane from forming. While some seedings seemed to correlate\n> with weaker hurricanes, the link was never adequately found and the project\n> was eventually abandoned.\n>\n> Instead, researchers are exploring two new options.\n>\n> Cyclones need hot sea surfaces to form. If we could cool the surface \u2013 such\n> as by piping chilled water from depths below 200 metres \u2013 we could prevent\n> the cyclone from ever forming.\n>\n> The problem is it's expensive. Norwegian cyclone-busting startup OceanTherm\n> estimates it would cost about AUD750 million to develop the technology, and\n> another AUD105 million every year to keep it going.\n\n> And worse, cooling one area of the sea does nothing to stop cyclones from\n> forming elsewhere. Models suggest ocean cooling will, at best, have only a\n> limited dampening effect on cyclones.\n>\n> There's a more likely option \u2013 aerosol injection. Scientists already know\n> that dust blown from the Sahara into the Atlantic reduces cyclone formation.\n> We could use planes or drones to inject hygroscopic (water-attracting)\n> particles into the lower atmosphere, where they would reflect and scatter\n> sunlight and trigger rainfall and energy release.\n>\n> This method has a stronger scientific pedigree, given it already occurs\n> naturally. But we don't know what side-effects it would have and we still\n> aren't sure what happens to energy redistributed by the intervention."}
{"query":"What events took place in our Solar System which led to formation of the Earth? I have heard from sources that a big giant star exploded and the Earth was formed. Is this true ?","reasoning":"A supernova explosion about 5 billion years ago deposited heavy elements into a nearby cloud of hydrogen gas and dust. The cloud collapsed under gravity, forming a new star at its center (the Sun) surrounded by a white-hot disk. The disk eventually formed Earth and the other planets in our solar system. Similar processes are observed in other parts of the universe.","id":"90","excluded_ids":["N\/A"],"gold_ids_long":["formation_of_earth\/Formation_and_evolution_of_the_Solar_System.txt","formation_of_earth\/Solar_radiation_modification.txt"],"gold_ids":["formation_of_earth\/Formation_and_evolution_of_the_Solar_System3.txt","formation_of_earth\/Formation_and_evolution_of_the_Solar_System2.txt","formation_of_earth\/Solar_radiation_modification3.txt"],"gold_answer":"$\\begingroup$\n\nThe following quote from [ Birth of the Earth\n](http:\/\/geology.about.com\/od\/nutshells\/a\/aa_earthbirth.htm) explains the\ncurrent theory\/model for the formation of the Solar System:\n\n> Long, long ago (some 5 billion years ago) in a perfectly ordinary place in\n> the galaxy, a supernova exploded, pushing a lot of its heavy-element\n> wreckage into a nearby cloud of hydrogen gas and interstellar dust. The\n> mixture grew hot and compressed under its own gravity, and at its center a\n> new star began to form. Around it swirled a disk of the same material, which\n> grew white-hot from the great compressive forces. That new star became our\n> Sun, and the glowing disk gave rise to Earth and its sister planets. We can\n> see just this sort of thing happening elsewhere in the universe.\n\nRead this article from Wikipedia as well.\n\n[\nhttps:\/\/en.wikipedia.org\/wiki\/Formation_and_evolution_of_the_Solar_System#Formation_of_planets\n](https:\/\/en.wikipedia.org\/wiki\/Formation_and_evolution_of_the_Solar_System#Formation_of_planets)"}
{"query":"Seems like the Earth Day related crowd sourcing project to create the first global soundscape by encouraging smartphone owners around the world to download and use an app developed to record the sounds around them is interesting, though it's unclear what scientific value it would have. Is there any scientific value to understanding soundscapes on a global basis?","reasoning":"Remote sensing uses signals like passive sonar and seismograms to indirectly measure objects or phenomena through related variables. Soundscape ecology studies the impact of sound on organisms, including biophony, geophony, and anthrophony. Soundscapes play a crucial role in ecological processes, but anthropogenic noise pollution negatively affects organisms. Preserving natural soundscapes is an important conservation goal.","id":"91","excluded_ids":["N\/A"],"gold_ids_long":["remote_sensing\/Remote_sensing_Acoustic_and_near_acoustic.txt","remote_sensing\/Soundscape_ecology.txt"],"gold_ids":["remote_sensing\/Soundscape_ecology4.txt","remote_sensing\/Remote_sensing_Acoustic_and_near_acoustic3.txt","remote_sensing\/Remote_sensing_Acoustic_and_near_acoustic4.txt"],"gold_answer":"$\\begingroup$\n\n> Remote sensing using [ passive sonar and seismograms\n> ](http:\/\/en.wikipedia.org\/wiki\/Remote_sensing#Acoustic_and_near-acoustic) ,\n> which are acoustic or near-acoustic signals, works on the principle of the\n> inverse problem. While the object or phenomenon of interest (the state) may\n> not be directly measured, there exists some other variable that can be\n> detected and measured (the observation), which may be related to the object\n> of interest through the use of a data-derived computer model.\n>\n> [ Soundscape ecology ](http:\/\/en.wikipedia.org\/wiki\/Soundscape_ecology) is\n> the study of sound within a landscape and its effect on organisms. Sounds\n> may be generated by organisms (biophony), by the physical environment\n> (geophony), or by humans (anthrophony). Soundscape ecologists seek to\n> understand how these different sound sources interact across spatial scales\n> and through time. Variation in soundscapes may have wide-ranging ecological\n> effects as organisms often obtain information from environmental sounds.\n> Soundscape ecologists use recording devices, audio tools, and elements of\n> traditional ecological analyses to study soundscape structure. Increasingly,\n> anthrophony, sometimes referred to in older, more archaic terminology as\n> anthropogenic noise dominates soundscapes, and this type of noise pollution\n> or disturbance has a negative impact on a wide range of organisms. The\n> preservation of natural soundscapes is now a recognized conservation goal.\n>\n> Source: Wikipedia links referenced above."}
{"query":"What percentage of Earth's surface is arid?Is there available information on how much of Earth surface is arid climate?","reasoning":"The four arid climates, add up to 4.401\u00d7107km2\n of a total of 1.527\u00d7108km2.","id":"92","excluded_ids":["N\/A"],"gold_ids_long":["arid_area\/K_C3_B6ppen_climate_classification.txt","arid_area\/present_htm.txt","arid_area\/Earth.txt"],"gold_ids":["arid_area\/K_C3_B6ppen_climate_classification2.txt","arid_area\/present_htm3.txt","arid_area\/K_C3_B6ppen_climate_classification3.txt","arid_area\/K_C3_B6ppen_climate_classification5.txt","arid_area\/present_htm4.txt","arid_area\/Earth2.txt","arid_area\/K_C3_B6ppen_climate_classification4.txt"],"gold_answer":"$\\begingroup$\n\nIt will depend on the exact definition of \"arid\" and the period of time. But\nusing the widely used and accepted [ K\u00f6ppen climate classification\n](https:\/\/en.wikipedia.org\/wiki\/K%C3%B6ppen_climate_classification) , \"arid\"\nwould correspond to the four climates in [ climatic group B\n](https:\/\/en.wikipedia.org\/wiki\/K%C3%B6ppen_climate_classification#Group_B:_Dry_\\(desert_and_semi-\narid\\)_climates) : \" **Dry (desert and semi-arid) climates** \". Using [ the\nmost up-to-date present climate data (2006) ](http:\/\/koeppen-geiger.vu-\nwien.ac.at\/present.htm) provided by the [ WORLD MAPS OF K\u00d6PPEN-GEIGER CLIMATE\nCLASSIFICATION ](http:\/\/koeppen-geiger.vu-wien.ac.at\/) at 0.5\u00b0 of resolution,\nthat looks like this (in an equal area projection):\n\n[ ![enter image description here](https:\/\/i.sstatic.net\/sLj6J.png)\n](https:\/\/i.sstatic.net\/sLj6J.png)\n\nWe get that the four arid climates (group B), add up to $4.401 \\times 10^7\n{km}^2$ of a total of $1.527 \\times 10^8 {km}^2$ inventoried in the dataset (A\ngood match for the figure of of [ global land area of $1.489 \\times 10^8 km^2$\nlisted by wikipedia ](https:\/\/en.wikipedia.org\/wiki\/Earth) ), leading to a\ngrand total of **28.8% of Earth's land surface corresponding to arid\nclimates** ."}
{"query":"What Magnitude does it Feel Like when Far Away in an Earthquake?\nI can't find a good way to say this but, if I had some info about an earthquake (i.e. magnitude 8, originating in water) and if I had a distance (i.e. 850 miles\/ 1370 km) could I calculate what it would be if that specific location was the epicenter? So, maybe it would be like a 3 or 4 maybe?I'm looking for a formula or calculator. If it is not possible, please tell me! It is fine if it is rough.","reasoning":"The Richter and other magnitude scales measure the energy released by an earthquake, while intensity scales like the Mercalli scale measure the shaking or damage experienced at a specific location, which depends on factors such as distance from the earthquake and local soil conditions.","id":"93","excluded_ids":["N\/A"],"gold_ids_long":["feel_earthquake\/Seismic_intensity_scales.txt","feel_earthquake\/Seismic_magnitude_scales.txt"],"gold_ids":["feel_earthquake\/Seismic_magnitude_scales4.txt","feel_earthquake\/Seismic_magnitude_scales3.txt","feel_earthquake\/Seismic_intensity_scales4.txt"],"gold_answer":"$\\begingroup$\n\nThe question doesn't really make sense.\n\nThe Richter and other [ seismic magnitude scales\n](https:\/\/en.wikipedia.org\/wiki\/Seismic_magnitude_scales) are measures of how\nmuch energy was released by an earthquake or how much work it did. An\nearthquake doesn't \"feel like\" any particular magnitude at any given point;\nrather, magnitude is an inherent attribute of the earthquake itself.\n\n\"Feels like\" is measured on [ seismic intensity scales\n](https:\/\/en.wikipedia.org\/wiki\/Seismic_intensity_scales) such as the Mercalli\nscale. These measure the peak acceleration or velocity at a given point, or\nthe damage done by the earthquake. Intensity is influenced by many things,\nsuch as the depth of the earthquake, the distance to the ruptured section of\nthe fault, and the local surface material.\n\nTranslating between the two is difficult, and requires knowing the detailed\ngeology of the area involved. The picture below is a USGS map of two\nearthquakes of comparable magnitude, the [ 1994 Northridge earthquake\n](https:\/\/en.wikipedia.org\/wiki\/1994_Northridge_earthquake) and an 1895\nearthquake on the [ New Madrid Seismic Zone\n](https:\/\/en.wikipedia.org\/wiki\/New_Madrid_Seismic_Zone#1812%E2%80%931900) .\nIn both cases, the outer zone is an intensity of Mercalli II or above, while\nthe inner zone is an intensity of Mercalli VI or above.\n\n[ ![A map of the United States, showing the effects of two earthquakes.  The\n1994 Northridge earthquake affected an area consisting mostly of southern\nCalifornia, with a small damage area.  The 1895 New Madrid earthquake affected\nmost of the eastern United States, with a damage area covering large parts of\nTennessee, Kentucky, Ohio, Indiana, Illinois, and\nMissouri.](https:\/\/i.sstatic.net\/yP3vh.jpg) ](https:\/\/i.sstatic.net\/yP3vh.jpg)"}
{"query":"For some time now, I've noticed that mountains in southeast Asia seem to be unusually \"jagged\" with steep surfaces. My basic knowledge of how mountains are formed (via geologic processes) tells me that it's more common to find mountains like these in glacial areas (e.g. northern Canada, Norway, etc.), whereas those formed by tectonic plate collisions appear more \"traditional\" (e.g. main range of Himalayas, Andes, etc.), and geologically old mountains have a weathered appearance (e.g. Appalachians).\r\n\r\nWhat caused\/causes these SE Asian mountains to have their distinct appearance?","reasoning":"The \"jagged mountains\" in SE Asia is just Karst landform","id":"94","excluded_ids":["N\/A"],"gold_ids_long":["karst\/Karst.txt"],"gold_ids":["karst\/Karst3.txt"],"gold_answer":"$\\begingroup$\n\nDavid Hammen has already answered with the correct term in his comment.\n\n* * *\n\nKarsts are formed as water dissolve rocks, typically [ carbonates\n](https:\/\/en.wikipedia.org\/wiki\/Carbonate_rock) (as limestone or dolomite) or\n[ evaporites ](https:\/\/en.wikipedia.org\/wiki\/Evaporite) .\n\nKarst landscapes can originate from karst caves, formed by groundwater flowing\nthrough the rocks. When the caves eventually collapse ( [ see image here\n](http:\/\/1.bp.blogspot.com\/_JRp7TJWTx4A\/S8Zvpncq70I\/AAAAAAAAAVU\/HPmQaOgb0d8\/s1600\/KarstDiagram-70pct-730206.jpg)\n) a rugged landscape is left behind. Karsts are also formed on the surface as\nlimestone dissolves and forms spectacular landscapes, as the [ Tsingy\n](https:\/\/en.wikipedia.org\/wiki\/Tsingy_de_Bemaraha_Strict_Nature_Reserve) in\nMadagascar or from sea erosion, e.g. [ calanques\n](https:\/\/en.wikipedia.org\/wiki\/Calanque) (karstic valleys).\n\n[ ![\\(My own picture.\\)](https:\/\/i.sstatic.net\/t22se.jpg)\n](https:\/\/i.sstatic.net\/t22se.jpg)\n\nThe landscape is also known as [ Pepino Hills\n](https:\/\/www.britannica.com\/science\/pepino-hill) sometimes [ mogotes\n](https:\/\/en.wikipedia.org\/wiki\/Mogote) , if they are surrounded by flat\nlandscape.\n\nAnother interesting feature is that as karst caves collapse, the cavity fills\nup with material from the ceiling and the cavity can continue to migrate\nupwards through the stratigraphy. Those karsts can be important channels for\ngroundwater or petroleum. Sometimes the collapse material is more resistant to\nerosion than the surrounding rocks, and we get pinnacles of karst breccia left\nbehind."}
{"query":"According to this article from 2015 How much oil is left on Earth\r\n\r\n1.5 trillion barrels of crude oil reserves were left in the world by end 2015\r\n\r\nBut how much oil was already consumed worldwide since it was started to use massively in the mid 19th century? Is it most of it or a small part of it?\r\n\r\nPS: I'm not sure if this question is for Earth Science SE or for Economy SE, if you think it's in the wrong SE please move it.","reasoning":"The articles critique the U.S. Energy Information Administration (EIA) for making overly optimistic forecasts about future oil production levels. The EIA's past forecasts for regions like the North Sea, Mexico, Alaska, and the Gulf of Mexico significantly overestimated actual production levels. For shale\/tight oil plays like the Bakken and Eagle Ford, high decline rates necessitate constant new drilling just to maintain output, suggesting tight oil production is a short-term phenomenon. Overall, the articles argue the EIA portrays economically recoverable oil resources as much larger than they likely are, with depletion of finite oil supplies happening more rapidly than the EIA's rosy forecasts indicate.","id":"95","excluded_ids":["N\/A"],"gold_ids_long":["world_oil\/oil_supply.txt"],"gold_ids":["world_oil\/oil_supply2.txt","world_oil\/oil_supply3.txt","world_oil\/oil_supply1.txt","world_oil\/oil_supply4.txt"],"gold_answer":"$\\begingroup$\n\n[ Cumulative world oil production at the end of 2017 was approximately 1.36\ntrillion barrels ](https:\/\/www.resilience.org\/stories\/2018-03-12\/the-world-\noil-supply-is-infinite-i-know-that-because-i-believe-it\/) ."}
{"query":"I have a theoretical exercise where I calculated the amount of CO2 that is released to the atmosphere per year (4.6 ppm). We assume that the relative increase of CO2 is 2 ppm, hence the percentage of CO2 that stays in the atmosphere is around 2\/4.6 ~ 40 %.\r\n\r\nWhat is the technical term for this percentage?","reasoning":"The persontage of co2 in atmosphere is a phenomenon called airborne fraction","id":"96","excluded_ids":["N\/A"],"gold_ids_long":["airborne_fraction\/Airborne_fraction.txt"],"gold_ids":["airborne_fraction\/Airborne_fraction4.txt","airborne_fraction\/Airborne_fraction5.txt","airborne_fraction\/Airborne_fraction3.txt"],"gold_answer":"$\\begingroup$\n\nWe call this the [ airborne fraction\n](https:\/\/en.wikipedia.org\/wiki\/Airborne_fraction) , although as the name\nsuggests, it's normally expressed as a fraction rather than a percentage.\n\n[ Raupach et al (2014) ](https:\/\/www.biogeosciences.net\/11\/3453\/2014\/) is an\n(open access) example of it being used in the literature, and in that paper\nthey quote a long-term 1959 to 2012 value of 0.44, so in the same ball-park as\nyour estimate. Similarly, here's an example of it's use in [ Chapter 7 of the\nIPCC AR4 ](https:\/\/ipcc.ch\/publications_and_data\/ar4\/wg1\/en\/ch7s7-3-5-2.html)\nwith a range of modelled values from 0.4 to 0.5. It's also often calculated\nover single years, as in your example, to look at the trends and variability.\n\nAs an aside, the 2 ppm in your calculation is called the [ atmospheric CO2\ngrowth rate ](https:\/\/www.newscientist.com\/article\/2112153-a-pause-in-growth-\nrate-of-atmospheric-co2-is-over-heres-why\/) and the total mass of CO2 in the\natmosphere would be the atmospheric CO2 _burden_ ."}
{"query":"Reviewing market regulatory standards I came across the problem of finding a source that I could cite of concise, worldwide accepted industry geophysical terms.\r\n\r\nSo far I know Schlumberger Oilfield Glossary, SEG Wiki, SPE PetroWiki that give some information on some terms. In practice I need something like this definition in SEG Wiki for seismic crooked lines. Although in this case I don't think the term is well defined.\r\n\r\nI am looking for a worldwide industry accepted glossary that I could rely on and cite. The broader it is the best will be for having less problems in future. Where would be the best place to find such source of information? Any other suggestions will be welcome.\r\n\r\n","reasoning":"Sheriff's Encyclopedic Dictionary is the closest thing to a canonical text, but the Schlumberger glossary is more up to date.","id":"97","excluded_ids":["N\/A"],"gold_ids_long":["glossary_of_oil\/seg.txt"],"gold_ids":["glossary_of_oil\/seg4.txt","glossary_of_oil\/seg3.txt","glossary_of_oil\/seg2.txt"],"gold_answer":"$\\begingroup$\n\n**Sheriff's _Encyclopedic Dictionary_ is the closest thing to a canonical\ntext, but the Schlumberger glossary is more up to date. **\n\n[ Sheriff ](http:\/\/wiki.seg.org\/wiki\/Dictionary:Sheriff's_Dictionary) is a\nscientific text, whereas the Schlumberger glossary is a little more generally\naccessible, but neither is comprehensive. Sheriff is especially poor on recent\nadvances. On the plus side, you can edit it, if you're an SEG member.\n\nAfter those two, Wikipedia is probably your next best bet."}
{"query":"I need US monthly climate data for the years 1992-2012. It would be great to get down to a county level, but by state would be just fine. Every site that I go to inevitably kicks me to the NCDC, but I cannot make sense of their data.\r\n\r\nFor example: the .csv sample data for GHCN Monthly Summaries lists EMXT (extreme maximum temperature) for each month of 2010 in Petersburg, ND. July had an EMXT of 317. I've been through the documentation, but I can't figure out what that number is supposed to mean. I know it wasn't 317F or C in ND at any point. Did they add all the temps up? Was it around 10C every day of July 2010? But why would you do that? The .PDF data looks like actual temperatures, but I need a lot of data: .CSV is ideal; .PDF is really not useable for the amount of data I am going to manipulate.\r\n\r\nWhat am I missing? Or is there another way to get this data?","reasoning":"Air Temperature (all units in Fahrenheit on PDF monthly form and tenths of degrees Celsius on CSV or text)\r\nEMNT - Extreme minimum temperature *\r\nEMXT - Extreme maximum temperature *","id":"98","excluded_ids":["N\/A"],"gold_ids_long":["ncdc_data\/docu.txt"],"gold_ids":["ncdc_data\/docu4.txt","ncdc_data\/docu5.txt","ncdc_data\/docu2.txt","ncdc_data\/docu1.txt","ncdc_data\/docu3.txt"],"gold_answer":"$\\begingroup$\n\nThe [ documentation linked from the datasets page\n](http:\/\/www1.ncdc.noaa.gov\/pub\/data\/cdo\/documentation\/GHCNDMS_documentation.pdf)\nstates:\n\n> Air Temperature (all units in Fahrenheit on PDF monthly form and **tenths of\n> degrees Celsius** on CSV or text)  \n>  EMNT - Extreme minimum temperature *  \n>  EMXT - Extreme maximum temperature *\n\nThe [ Petersburg data\n](http:\/\/www1.ncdc.noaa.gov\/pub\/data\/cdo\/samples\/GHCNDMS_sample_ascii.dat)\nlooks plausible under this interpretation (EMXT \u22123.9\u00b0C to 33.9\u00b0C over the\nyear)."}
{"query":"This is a question on methodology. But I have 4d temperature and salinity gridded data (time, depth, lat and lon). The time is in monthly time steps. How would I get the annual harmonics of temperature and salinity using a periodicity of 12 months:\r\n\r\nThe equation is:\r\n\r\nVar(t,z,y,x)=A(z,y,x)\u2217cos[(2\u03c0t\/P+\u03d5(z,y,x)]\r\n\r\nWhere A\r\n is the amplitudes of the annual component, where var\r\n is either temp or salinity. \u03d5\r\n is the phase angle which determine the time when the maximum of the annual harmonic occurs. And t\r\n varies from 0 - n months (however long the time series is).\r\n\r\nWe can isolate A(z,y,x)\r\n just with algebra, but the issue is finding the phase angle where the maximum of the annual harmonic occurs.\r\n\r\nDo you you need to take a fourier transform of monthly means (January - December), or do you take the FT of the entire time series but just look at the power spectrum at 12 months... I am using Python, and taking the fourier transform is no problem. I just don't know how to treat the data to obtain the phase angle where the maximum of the annual harmonic occurs. What might be the steps to find the annual h","reasoning":"Using the theory of Trigonometry\/Simplifying a sin(x) + b cos(x), we can determine the  annual harmonics of temperature and salinity data","id":"99","excluded_ids":["N\/A"],"gold_ids_long":["annual_harmonics\/Simplifying_a_sin(x)__2B_b_cos(x).txt"],"gold_ids":["annual_harmonics\/Simplifying_a_sin(x)__2B_b_cos(x)1.txt","annual_harmonics\/Simplifying_a_sin(x)__2B_b_cos(x)3.txt","annual_harmonics\/Simplifying_a_sin(x)__2B_b_cos(x)2.txt","annual_harmonics\/Simplifying_a_sin(x)__2B_b_cos(x)4.txt"],"gold_answer":"$\\begingroup$\n\nWith a little bit of math:\n\n$$ A * \\cos [ (2 \\pi t\/P + \\phi] = a\\sin(2\\pi t\/P)+b\\cos(2\\pi t\/P)$$\n\nThen, the amplitude is:\n\n$$A=\\sqrt{a^2+b^2}$$  and the phase is  $$\\phi=\\arctan{\\frac{b}{a}}$$\n\n[ https:\/\/en.wikibooks.org\/wiki\/Trigonometry\/Simplifying_a_sin(x)_%2B_b_cos(x)\n](https:\/\/en.wikibooks.org\/wiki\/Trigonometry\/Simplifying_a_sin\\(x\\)_%2B_b_cos\\(x\\))"}
{"query":"Which plant is the most efficient in making oxygen for it's weight? I want to think it is the greenest plant with more leaves and least trunk in full sun?","reasoning":"Algae, tiny plants in water, create green slime on rocks and produce abundant oxygen, sustaining aquatic life globally.","id":"100","excluded_ids":["N\/A"],"gold_ids_long":["plant_produce_oxygen\/algae_htm.txt"],"gold_ids":["plant_produce_oxygen\/algae_htm3.txt"],"gold_answer":"$\\begingroup$\n\nI just read an article saying that algae produces more oxygen than all the\nplants in the world!! Edit: [ https:\/\/www.nps.gov\/romo\/learn\/nature\/algae.htm\n](https:\/\/www.nps.gov\/romo\/learn\/nature\/algae.htm) First paragraph last lines"}
{"query":"Quite simply what is the highest point above sea level that is right on the equator, I figured it would be a mountain in the Ecuadorian Andes but the Kenyan highlands look to be a likely candidate as well. I've tried to find it but I simply can't find a map that has the equator and the altitude in a highly accurate format and resolution anywhere.","reasoning":" Volc\u00e1n Cayambe is the furthest point that on the equator we can find.","id":"101","excluded_ids":["N\/A"],"gold_ids_long":["far_from_sea_level\/how_far_above_sea_level_can_you_get_on_the_equator.txt"],"gold_ids":["far_from_sea_level\/how_far_above_sea_level_can_you_get_on_the_equator3.txt","far_from_sea_level\/how_far_above_sea_level_can_you_get_on_the_equator2.txt"],"gold_answer":"$\\begingroup$\n\nI would assume that's the highest point on the equator you talking about, so\nThe highest point on the Equator is at the elevation of 4,690 metres (15,387\nft), at 0\u00b00\u20320\u2033N 77\u00b059\u203231\u2033W, found on the southern slopes of [ Volc\u00e1n Cayambe\n](https:\/\/en.wikipedia.org\/wiki\/Cayambe_\\(volcano\\)) [summit 5,790 metres\n(18,996 ft)] in Ecuador. This is slightly above the snow line and is the only\nplace on the Equator where snow lies on the ground."}
{"query":"Is wind just mainly nitrogen particles moving in one direction?\r\nThe air is composed of mainly nitrogen. Therefore, when you feel wind, is it mainly nitrogen particles hitting you that, on average, are moving in one direction?","reasoning":"Behind wind formation, is a theory of brownian movement of molecules. ","id":"102","excluded_ids":["N\/A"],"gold_ids_long":["wind_movement\/Brownian_motion.txt"],"gold_ids":["wind_movement\/Brownian_motion2.txt","wind_movement\/Brownian_motion4.txt","wind_movement\/Brownian_motion1.txt","wind_movement\/Brownian_motion3.txt","wind_movement\/Brownian_motion5.txt"],"gold_answer":"$\\begingroup$\n\nIn a nutshell, you're a little bit right. The Air pressure is essentially\nNitrogen and Oxygen molecules hitting our bodies, but that's true with and\nwithout wind.\n\nwind is more easily explained from the macro-scale not the micro-scale. It's\nnot molecular behavior but governed by forces like high and low pressure\nsystems and weather, or, fans if you're indoors.\n\n[ The Brownian ](https:\/\/en.wikipedia.org\/wiki\/Brownian_motion) motion of\nmolecules is pretty consistent like 3d billiard balls, though velocity of the\nmolecules increases with temperature. This is kind of what air molecules\nmovement looks like:\n\n[\n![https:\/\/upload.wikimedia.org\/wikipedia\/commons\/6\/6d\/Translational_motion.gif](https:\/\/i.sstatic.net\/BAEQ9.gif)\n](https:\/\/i.sstatic.net\/BAEQ9.gif)\n\nWind is, in a nutshell, the entire box moving, not individual particles\nchanging direction, but it could probably be looked at either way.\n\nIf all the air molecules, by some strange coincidence, all moved in the same\ndirection 2 things would happen. One, the air would get very cold as\ntemperature is essentially agitated molecules moving or vibrating against each\nother, and two, the wind speed would be over 1000 kph. Roughly the speed of\nsound. Fortunately this kind of thing is so statistically improbable it\nessentially never happens."}
{"query":"My understanding of climate change is that a large increase in human-caused CO2 emissions is likely to lead to large change in the Earth's climate through a global warming effect. Scientific consensus appears to me to be that if we make similarly large reductions in CO2 emissions, we can reduce the magnitude of the consequent warming.\r\n\r\nI also understand the climate to have many non-linear mechanisms whereby the link between emission and warming isn't at all straightforward - and so we can only talk about broad averages and so forth, rather than make specific weather predictions.\r\n\r\nSo is it always true that a reduction in emissions will - on average - cause a reduction in the global warming effect, however small? Or does the existence of tipping points or any other factor mean that only large reductions can make a difference now and any lesser reduction will be pointless?\r\n\r\nMy intuition says that smaller cuts in emissions should still be preferred to no cuts at all, as I imagine that they would reduce the peak warming and\/or delay the peak for longer and\/or reduce the eventual recovery time. Perhaps not by as much as we might prefer, but still better than nothing. But perhaps my intuition is off.","reasoning":"the relationship between emissions and climate change is complex due to the non-linear mechanisms in the climate system.","id":"103","excluded_ids":["N\/A"],"gold_ids_long":["co2_breakdown\/Carbon_budget.txt","co2_breakdown\/co2_budget_html.txt"],"gold_ids":["co2_breakdown\/co2_budget_html3.txt","co2_breakdown\/Carbon_budget3.txt"],"gold_answer":"$\\begingroup$\n\nYes, because carbon emissions [ are like a budget\n](https:\/\/en.wikipedia.org\/wiki\/Emissions_budget) . The Mercator Institute has\none of the most commonly cited [ analyses of our carbon budget\n](https:\/\/www.mcc-berlin.net\/en\/research\/co2-budget.html) :\n\n> the atmosphere can absorb, calculated from end-2017, no more than 420\n> gigatonnes (Gt) of CO  2  if we are to stay below the 1.5\u00b0C threshold.\n> Annual emissions of CO  2  \u2013 from burning fossil fuels, industrial processes\n> and land-use change \u2013 are estimated to be around 42 Gt per year, the\n> equivalent of 1,332 tonnes per second. With emissions at a constant level,\n> the budget would be expected to be used up in less than seven years from\n> now. The budget for staying below the 2\u00b0C threshold, for its part, of\n> approximately 1,170 Gt, would be exhausted in about 25 years.\n\nSo, just like a household or business budget, small (but persistent)\nreductions in spending\/emissions do make a difference in the long run."}
{"query":"I've been reading up about Gravitational Models and Spherical Harmonics.\r\n\r\nWhere I first read about them is in this scholarly article on Autonomous navigation with Gravity Gradients. It talks about Gravity Models being of order x and degree y.\r\n\r\nWhat does order and degree mean in this circumstance? Is it something to do with the Lagrangian Polynomials used in the models?\r\n\r\nAnother example is found here which states that EGM2008 is complete to spherical harmonic degree and order 2159","reasoning":"Spherical harmonics are mathematical functions used to describe patterns on a sphere. The degree (l) and order (m) of a spherical harmonic function determine its properties. The order represents the number of waves when moving around the sphere at a constant latitude, while the degree, taking the order into account, indicates the number of zero crossings when traveling from pole to pole.","id":"104","excluded_ids":["N\/A"],"gold_ids_long":["spherical_harmonics\/Spherical_harmonics.txt"],"gold_ids":["spherical_harmonics\/Spherical_harmonics2.txt","spherical_harmonics\/Spherical_harmonics1.txt"],"gold_answer":"$\\begingroup$\n\nCiting from [ Wikipedia ](https:\/\/en.wikipedia.org\/wiki\/Spherical_harmonics) :\n$Y_l^m$  is called a spherical harmonic function of degree  $l$  and order\n$m$  . If we take the real part of the spherical harmonics only, there is a\nnice visual explanation for order and degree.\n\nThe order  $m$  is the zonal wave number, that is how many waves we count\nwalking around the sphere at constant latitude. The degree is a little more\ndifficult to interpret, because we need to take the order into account:\n$l-|m|$  is the number of zero crossings if we walk from pole to pole.\n\nBelow you can see an example for  $l=3$  and  $0\\leq m \\leq 3$  (keep in mind\nthat in order to count the number of zonal waves you also have to walk around\nthe \"back\" of the sphere which you can not see in the picture): [ ![enter\nimage description here](https:\/\/i.sstatic.net\/1sGCD.png)\n](https:\/\/i.sstatic.net\/1sGCD.png)"}
{"query":"I just found a video on sedimentary rock formation, and to my surprise, it stated that this only could occur in water! I always thought that any layer of matter, if buried deep underneath more matter, could form a sediment and become new rock. Am I completely wrong, or was the video simply not covering all bases?\n\nI did Google it and check Wikipedia, but with my limited knowledge of the field, the results were inconclusive.","reasoning":"While not all sediments require water for deposition, water plays a crucial role in the formation of most sedimentary rocks through processes like compaction, diagenesis, dissolution, and cementation.","id":"105","excluded_ids":["N\/A"],"gold_ids_long":["sendimentation_without_water\/Breccia.txt","sendimentation_without_water\/Tuff.txt","sendimentation_without_water\/Eolianite.txt"],"gold_ids":["sendimentation_without_water\/Eolianite5.txt","sendimentation_without_water\/Breccia3.txt","sendimentation_without_water\/Tuff3.txt"],"gold_answer":"$\\begingroup$\n\n**Not all sediments are deposited in water, but water is important in the\nformation of most sedimentary rocks.**\n\nIf we're just thinking about the deposition of the sediment, then we don't\nnecessarily need water. Some counterexamples are:\n\n  * [ **Aeolian sandstones** ](https:\/\/en.wikipedia.org\/wiki\/Eolianite) , such as the Lower Permian Rotliegend sandstone of the North Sea. These are deposited by wind, not water. \n  * Some types of [ **sedimentary breccia** ](https:\/\/en.wikipedia.org\/wiki\/Breccia) , which are chiefly deposited by gravity, not water. \n  * [ **Tuff** ](https:\/\/en.wikipedia.org\/wiki\/Tuff) , which are deposited by gravity and wind, not water. They also undergo substantial compaction and lithification with or without water. \n\nBut deposited sediment does not a rock make. Once deposited and if buried,\nmost sediment undergoes compaction and diagenesis, eventually lithifying \u2014 a\nfancy word for turning into a rock. Below the water table, the shallow crust\nis saturated with (mostly) saline water, and processes like dissolution and\ncementation are necessarily aqueous. So it's fair to say that water is\nessential in the formation of sedimentary rocks, on Earth anyway.\n\n###  Footnote\n\nYou were right to be skeptical, by the way; the video is introductory material\napparently intended for grade school audience, so you can't treat it like a\ntextbook. And you can't even take a textbook as 'truth', especially when it\ncomes to slippery things like definitions. Sometimes generalizations and\nsimplifications help, sometimes they don't."}
{"query":"When was the first not-icy desert formed?For how long have deserts existed and which one would be the first to be created? I'm talking about arid, dry deserts, not the Antarctic or Arctic or any other icy deserts.","reasoning":"Deserts have existed since at least the Permian period, but the current desert environments we see today are relatively recent, dating back to about 65.5 million years ago. The development of modern deserts is attributed to the progressive cooling and aridification of global climates during the Cenozoic Era. The oldest \"modern\" desert is believed to have emerged in what is now North Africa or South Asia.","id":"106","excluded_ids":["N\/A"],"gold_ids_long":["not_icy_desert\/permian_php.txt","not_icy_desert\/desert.txt"],"gold_ids":["not_icy_desert\/permian_php4.txt","not_icy_desert\/permian_php5.txt","not_icy_desert\/permian_php3.txt","not_icy_desert\/permian_php1.txt","not_icy_desert\/permian_php2.txt","not_icy_desert\/desert5.txt"],"gold_answer":"$\\begingroup$\n\nDeserts have existed since at least the Permian period (299-251 million years\nago) when the world's continents had combined into the Pangaea supercontinent.\nStretching from pole to pole, this land mass was large enough that portions of\nits interior received little or no precipitation, [ according the University\nof California Museum of Paleontology\n](https:\/\/ucmp.berkeley.edu\/permian\/permian.php) .\n\nPangaea broke into smaller land masses which were moved across the surface by\ntectonic forces, a process that both changed global climate patterns and the\nclimate those continents were exposed to. As a result, current desert regimes\ndate back to no more than 65.5 million years, according to [ this Encyclopedia\nBritannica article ](https:\/\/www.britannica.com\/science\/desert) :\n\n> The desert environments of the present are, in geologic terms, relatively\n> recent in origin. They represent the most extreme result of the progressive\n> cooling and consequent aridification of global climates during the Cenozoic\n> Era (65.5 million years ago to the present), which also led to the\n> development of savannas and scrublands in the less arid regions near the\n> tropical and temperate margins of the developing deserts. It has been\n> suggested that many typical modern desert plant families, particularly those\n> with an Asian centre of diversity such as the chenopod and tamarisk\n> families, first appeared in the Miocene (23 to 5.3 million years ago),\n> evolving in the salty, drying environment of the disappearing Tethys Sea\n> along what is now the Mediterranean\u2013Central Asian axis.\n\nWhich would put the oldest of \"modern\" desert somewhere in the region of what\nlater became North Africa or South Asia."}
{"query":"Some days I can smell bad smelling exhaust 50 meters or more away from the bus stop. I think the air is usually moist those days.\n\nDoes exhaust gases linger longer if the air is moist near the ground? Is it smog I am smelling those days?\n\nOn morning 12 march it was about\n\nTemperature: 4\u00b0C\nHumidity:93%\nBarometer:978 mbar\nWind:10 m\/s\nLooking at the data from earth.nullschool.net at a few hours before that morning I saw surface temperature of 5.1\u00b0C and 5.8\u00b0C at 1000hPa.","reasoning":"When we smell something, we are inhaling gases or particles. These don't accumulate in the atmosphere due to transport, chemistry, and deposition processes. Atmospheric chemistry, involving compounds like the hydroxyl radical (OH), converts odorous pollutants into simpler chemicals we don't smell. Deposition occurs through precipitation and settling of particles. While some pollutants may take years to convert, they eventually deposit on Earth's surface. Stagnation events can trap stinky air near the ground, but overall, the atmosphere maintains a balance through these processes.","id":"107","excluded_ids":["N\/A"],"gold_ids_long":["exhaust_smells\/Odor.txt","exhaust_smells\/where_do_bad_smells_eventually_go.txt","exhaust_smells\/Air_pollution.txt"],"gold_ids":["exhaust_smells\/where_do_bad_smells_eventually_go2.txt","exhaust_smells\/Odor4.txt","exhaust_smells\/Air_pollution2.txt","exhaust_smells\/where_do_bad_smells_eventually_go3.txt","exhaust_smells\/Air_pollution3.txt"],"gold_answer":"$\\begingroup$\n\nYou can see [ this post\n](https:\/\/earthscience.stackexchange.com\/questions\/13391\/where-do-bad-smells-\neventually-go\/13392#13392) for a more detailed discussion, but the typical\nanswer to your question is air stagnation. When the atmosphere is stable,\nthere is little mixing, and the air can stagnate. Typically this coincides\nwith low wind speeds and a low boundary layer. The boundary layer holds air\nnear the surface like a blanket. The boundary layer collapses overnight,\nbecoming shallow, and grows when the sun heats the surface of the Earth. So,\nin the morning, the shallow boundary layer allows less vertical mixing to\noccur.\n\nYou might be noticing that on cloudy days, when clouds are low, there is\nlittle wind and no solar heating. Air pollution has no place to go, so it\nsticks around.\n\nAnother aspect is that vehicles emit more emissions under cold-start\nconditions. This is because vehicles get cold overnight and take a while to\nget up to normal temperature when they startup in the morning. The cold\nvehicle will have a low combustion efficiency and catalytic converters won't\nwork as well."}
{"query":"I am listening to a song about volcanoes. It is called \"Pyroclastic Annihilation\" performed by a brutal deth\/thrash metal band called \"Demolition Hammer\". It is from their album \"Epidemic of Violence\" released in 1992. The song is: https:\/\/www.youtube.com\/watch?v=S_7qqsVioxo the full lyrics can be found here: https:\/\/genius.com\/Demolition-hammer-pyroclastic-annihilation-lyrics\n\nI have come across a term I do not understand.\n\nMolten debris\nVolcanic ash\nSeas of boiling mud\nSubrelluric forces exploding violently\nPyroclastic matter intense velocity\n\nIs the word \"Subrelluric\" a geological term? If yes what does it mean exactly? What are Subrelluric forces? What do they do amidst a volcanic eruption? I couldn't find anything on the web. Perhaps this is an extremely advance term not usually used in the public world?","reasoning":"Actually the \"Subrellutic\" is the word \"Telluric\", which means the earth.","id":"108","excluded_ids":["N\/A"],"gold_ids_long":["subrelluric\/Telluric.txt"],"gold_ids":["subrelluric\/Telluric5.txt"],"gold_answer":"$\\begingroup$\n\nI believe what you heard is \u201csubtelluric\u201d where [ telluric\n](https:\/\/en.wikipedia.org\/wiki\/Telluric \"telluric\") means \u201cof the earth\u201d."}
{"query":"In the mainstream media the problem of ocean level rise is presented rather... over-simplistically - ice melts -> more water flows into the oceans -> water level rises -> continents sink.\n\nBut it is in reality a complex system, it is not like pouring water in a glass... or a lake that resides on a continental plate.\n\nBoth continental and oceanic plates float on top of the mantle as both are lighter and lower density, and both exert weight and compress the mantle.\n\nTherefore, if water is removed from continental plates by means of melting ice, the continental plate gets lighter. And when that water migrates to the ocean, the oceanic plate gets heavier. And since for every action there is equal in force and opposite in direction reaction, it seems logical that the now heavier oceanic plate will actually push the now lighter continental plate up, to some extent compensating for or possibly even reversing the change in ocean level relative to the continental plate.\n\nSo, do the estimates account for the dynamic properties of that complex system?","reasoning":"Relative sea level is the sea level measured in relation to the continental crust, affected by changes in both sea level and land movements. Mean Sea Level (MSL) is the average water level over a specific period, measured relative to a fixed mark on land. MSL can change due to water volume or land movements. Long-term sea level changes include Glacial Isostatic Adjustment (GIA) caused by post-glacial land movements.","id":"109","excluded_ids":["N\/A"],"gold_ids_long":["sea_level_and_ele\/Post_glacial_rebound.txt","sea_level_and_ele\/Sea_level.txt","sea_level_and_ele\/Relative_sea_level.txt"],"gold_ids":["sea_level_and_ele\/Sea_level4.txt","sea_level_and_ele\/Relative_sea_level4.txt","sea_level_and_ele\/Post_glacial_rebound3.txt","sea_level_and_ele\/Relative_sea_level3.txt","sea_level_and_ele\/Sea_level3.txt"],"gold_answer":"$\\begingroup$\n\nSea level rise estimates use changes in [ relative mean sea level\n](http:\/\/www.coastalwiki.org\/wiki\/Relative_sea_level) . The definition being:\n\n> Relative sea level is the sea level related to the level of the continental\n> crust. Relative sea level changes can thus be caused by absolute changes of\n> the sea level and\/or by absolute movements of the continental crust.\n\nIn general, [ Mean Sea Level ](https:\/\/en.wikipedia.org\/wiki\/Sea_level) means\nthe 'water level when it is still' (without waves). MSL is averaged over a\ndetermined period of time, such as a month or a year and it is measured\nrelative to a fixed mark on the land (benchmark).\n\nAs MSL is measured relative to land, it can change due to changes in water\nvolume or due to land movements. That is why we usually refer to it as\n'relative sea level'.\n\nLong-term changes of sea level are called \"secular\" changes and include\nisostatic changes. The main reason for isostatic changes at a global scale is\nthe [ Glacial Isostatic Adjustment ](https:\/\/en.wikipedia.org\/wiki\/Post-\nglacial_rebound) (GIA).\n\nThe body of scientific work related to the contributions by different factors\nis extensive. For instance, I like [ Cazenave & Nerem, 2004\n](https:\/\/doi.org\/10.1029\/2003RG000139) . Also, there is a lot of information\nabout [ the relative contributions of each\n](https:\/\/sealevel.jpl.nasa.gov\/science\/ostscienceteam\/scientistlinks\/scientificinvestigations2013\/cazenave\/)\n.\n\n[ ![contributions](https:\/\/i.sstatic.net\/dFSot.jpg)\n](https:\/\/i.sstatic.net\/dFSot.jpg) Source: [ JPL-NASA\n](https:\/\/sealevel.jpl.nasa.gov\/science\/ostscienceteam\/scientistlinks\/scientificinvestigations2013\/cazenave\/)\n\nThere is a lot more information about the regional distribution of sea level\nrise in: [ How will sea level rise be distributed across the globe?\n](https:\/\/earthscience.stackexchange.com\/questions\/10876\/how-will-sea-level-\nrise-be-distributed-across-the-globe)\n\nAlso, [ here\n](http:\/\/homepages.see.leeds.ac.uk\/~lecimb\/SOEE3410\/lectures\/15-Sea-level-\nrise.ppt) is a good simple explanation of the factors affecting sea level."}
{"query":"I am a lay person in meteorology, maybe this is not the right place for my question, but I would like to ask then.\n\nMy question is simple: is there a website or institute that has integrated statistics on forecasting the occurrence of rainbows in different countries around the world?","reasoning":"A rainbow is not a physical object, but an optical phenomenon caused by sunlight interacting with raindrops. It depends on your location relative to the sun and rain. Due to the refraction, reflection, and refraction of light within raindrops, a concentration of outgoing rays forms a rainbow at an angle of 42 degrees above the observer's shadow. Different people see different rainbows because each person has a unique horizon and antisolar point. Rainbows cannot be precisely measured or cataloged like lightning. However, there are resources available, including apps, for predicting and photographing rainbows.","id":"110","excluded_ids":["N\/A"],"gold_ids_long":["forcasting_rainbow\/formatn_htm.txt","forcasting_rainbow\/frm_rxml.txt"],"gold_ids":["forcasting_rainbow\/frm_rxml4.txt","forcasting_rainbow\/formatn_htm2.txt","forcasting_rainbow\/formatn_htm5.txt","forcasting_rainbow\/formatn_htm3.txt","forcasting_rainbow\/frm_rxml3.txt","forcasting_rainbow\/formatn_htm4.txt","forcasting_rainbow\/frm_rxml5.txt"],"gold_answer":"$\\begingroup$\n\nA rainbow is not a physical object that has a position. It is an optical\nphenomena that depends on your location relative to the sun and rain. If you\nare standing where your eyes can intercept the colored light, you are standing\nwith your back to the sun and the sunlight is reflecting on raindrops in front\nof you. Someone else standing in a different location would not necessarily\nsee a rainbow if they looked up at the same part of the sky.\n\nFrom [ University of Illinois\n](http:\/\/ww2010.atmos.uiuc.edu\/\\(Gh\\)\/guides\/mtr\/opt\/wtr\/rnbw\/frm.rxml) :\n\n> According to Descartes' calculations using laws of optics, the three stage\n> refraction-reflection-refraction pattern that light undergoes when passing\n> through a raindrop produces a concentration of outgoing rays along a line\n> that is 42 degrees above the head of an observer's shadow. This\n> concentration of light rays is the rainbow that we see.\n\nAlso [ this National Geographic article\n](https:\/\/www.nationalgeographic.org\/encyclopedia\/rainbow\/print\/#:%7E:text=In%20fact%2C%20no%20one%20sees,his%20or%20her%20own%20horizon.)\nhas a nice description:\n\n> Viewers on the ground can only see the light reflected by raindrops above\n> the horizon. Because each person's horizon is a little different, no one\n> actually sees a full rainbow from the ground. In fact, no one sees the same\n> rainbow\u2014each person has a different antisolar point, each person has a\n> different horizon. Someone who appears below or near the \"end\" of a rainbow\n> to one viewer will see another rainbow, extending from his or her own\n> horizon.\n\nWhat this means is that a rainbow is not really a meteorological occurrence\nthat can be measured or catalogued, because you would get a different answer\ndepending on your reference point. Lightning, in contrast, is a physical\nphenomena that has a precise location which can be determined and verified\nfrom multiple points of reference.\n\nRainbows are photographed and archived by enthusiasts, but it's really about\nartistic appreciation. While I have not looked into rainbow forecast services,\na quick search shows some interesting resources, such as [ How to Predict\nRainbows and Plan Photographs ](https:\/\/stephenbayphotography.com\/blog\/how-to-\npredict-rainbows-and-plan-photographs\/) which has a link to a [ photography\napp that can plan for rainbows ](https:\/\/www.planitphoto.com\/#feature) and\nhere is a [ rainbow app you can install\n](http:\/\/www.erikscarlson.com\/project\/chance-of-\nrainbow#:%7E:text=Creating%20an%20algorithm%20to%20predict,\\(if%20that%20is%20possible\\).)\non your phone.\n\n[ How Rainbows Happen ](http:\/\/www.rebeccapaton.net\/rainbows\/formatn.htm) also\nhas a nice description (shown below) and some other useful resources. [\n![enter image description here](https:\/\/i.sstatic.net\/GEDyn.gif)\n](https:\/\/i.sstatic.net\/GEDyn.gif)"}
{"query":"I would like to know what would happen with the atmosphere of Venus when it gets tidally locked, i.e. when one side would perpetually face the Sun.\r\nProbably a thermal low would be at the subsolar region then.\r\n\r\nAt the surface Venus has an atmospheric pressure of 92 atm. and a temperature of 462\u2070\r\n C.\r\n\r\nAre there General Circulation Models or Global Climate Models that can handle such input parameters ?\r\n\r\nIf so, are there GCM users (groups, universities etc.) who could run a tidally locked Venus simulation ?","reasoning":"The OPUS-V and ROCKE-3D models, based on older versions of climate models, have been utilized for studying Venus. However, more recent models, such as those mentioned in the Yamamoto et al. (2019) introduction, provide an updated and diverse range of options from research groups worldwide.","id":"111","excluded_ids":["N\/A"],"gold_ids_long":["atmosphere_venus\/geophysical_and_astrophysical_fluid_dynamics.txt","atmosphere_venus\/nasa_climate_modeling_suggests_venus_may_have_been_habitable.txt"],"gold_ids":["atmosphere_venus\/geophysical_and_astrophysical_fluid_dynamics2.txt","atmosphere_venus\/nasa_climate_modeling_suggests_venus_may_have_been_habitable5.txt"],"gold_answer":"$\\begingroup$\n\nI'm not sure of their current status, but I read some papers based on these\nmodels a few years ago:\n\n  * [ Oxford Planetary Unified Model System ](https:\/\/www2.physics.ox.ac.uk\/research\/geophysical-fluid-dynamics\/research\/oxford-planetary-unified-model-system) for Venus (OPUS-V), which is based on an old version of the UK Met Office climate model, HadCM3 ( [ paper ](https:\/\/doi.org\/10.1016\/j.pss.2016.09.001) from 2016). \n\n  * ROCKE-3D at Nasa GISS, which is based on an old version of the GISS ModelE2\u2010R climate model ( [ blog article ](https:\/\/climate.nasa.gov\/news\/2475\/nasa-climate-modeling-suggests-venus-may-have-been-habitable\/) and [ paper ](https:\/\/doi.org\/10.1002\/2016GL069790) from 2016). \n\nIt looks like the introduction of [ Yamamoto et al\n](https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0019103518304846) (2019)\nhas a more up-to-date summary of the current set of models, and there's quite\na healthy selection from groups around the world."}
{"query":"Researchers who are involved in study of life on Mars are saying that there might be multicellular life present on Mars, today or in the past. Which traces, markers or environments on Mars could support this hypothesis and how it will be investigated?","reasoning":"The Mars 2020 mission aims to search for signs of past microbial life on Mars. It has two main objectives: finding fossils of extinct life forms that may have existed around 3-3.5 billion years ago when Mars had conditions suitable for life, and searching for present-day bacterial life on or near the Martian surface. The mission will focus on sampling rocks from potentially lifebearing areas, such as old lake beds like the Jezero Crater, known for its clay-rich delta formation.","id":"112","excluded_ids":["N\/A"],"gold_ids_long":["life_on_mars\/sedimentary_signs_of_martian_lakebed.txt","life_on_mars\/mars_2020_perseverance.txt"],"gold_ids":["life_on_mars\/sedimentary_signs_of_martian_lakebed5.txt","life_on_mars\/mars_2020_perseverance5.txt"],"gold_answer":"$\\begingroup$\n\nOne of the next big missions to Mars, named [ Mars 2020\n](https:\/\/mars.nasa.gov\/mars2020\/) is planned to depart from Earth to Mars\nduring late July 2020. This mission involve a [ very capable rover\n](https:\/\/mars.nasa.gov\/mars2020\/mission\/rover\/) , like [ Curiosity\n](https:\/\/mars.nasa.gov\/msl\/home\/) on steroids.\n\nFrom the mission site:\n\n> The mission takes the next step by not only seeking signs of habitable\n> conditions on Mars in the ancient past, but also searching for signs of past\n> microbial life itself.\n\nThis mean that there is two important objective:\n\n  1. to find **extinct life forms** , such as assuming there was conditions a long time ago permitting lifeforms to exist on Mars, likely 3-3.5 Billion years from now or so, in other words, fossils. Why 3-3.5 Gy ago? This was during Hesperian geological epoch when water was likely a major agent in forming channels lakes and rivers, thus with atmospheric and ground conditions possibly permitting the existence of life back then. \n  2. to find **extant life forms** such as bacteria that are existing presently on Mars surface or near surface. \n\nOne component of the mission is to sample rocks that are likely lifebearing,\nanalyze and store for a later pickup by a further mission. Lifebearing rocks\nin that case may be found as old lake beds, for example iron rich lacustrine\nmudstone.\n\nLacustrine mudstone is obviously originating from depositing fine sediments\nover a lake floor, a stable environment through a long time, as shown by\nlayers like [ this ](https:\/\/www.nasa.gov\/jpl\/msl\/pia19074) (pictured by\nCuriosity's MastCam in 2014). And iron rich is important as this chemical\narrangement is favoring and helping the preservation of microbial lifeforms.\n\n[ ![Jezero Crater, Mars](https:\/\/i.sstatic.net\/lyLXK.jpg)\n](https:\/\/i.sstatic.net\/lyLXK.jpg)\n\nSource: [ https:\/\/www.nasa.gov\/image-feature\/jezero-crater-mars-2020s-landing-\nsite ](https:\/\/www.nasa.gov\/image-feature\/jezero-crater-mars-2020s-landing-\nsite)\n\nAs can be seen in the picture, the big circle (as a crater) in the center of\nthe delta is named the Jezero crater and is the target landing site for Mars\n2020. This delta was formed due to water flowing in a lake; clay rich\ndeposited were detected in the area. The crater is exposing deeper (early)\nlayers in the delta, making this an ideal exploration site to look for extinct\nor extinct life."}
{"query":"Is there a package for R to plot Schmidt nets, like it is done in geology?\r\n\r\nSo far, I only know software like Stereonet. However I think it would make a lot of sense to handle these data in R, to have so much more possibilities in calculations and statistics.","reasoning":"While there is no specific package in R dedicated to plotting Schmidt nets for geology, the RockFab package in R can be a useful tool for geological analysis and visualization.","id":"113","excluded_ids":["N\/A"],"gold_ids_long":["schmidt_nets\/rf.txt","schmidt_nets\/rfpdf.txt"],"gold_ids":["schmidt_nets\/rfpdf3.txt","schmidt_nets\/rf3.txt","schmidt_nets\/rfpdf5.txt","schmidt_nets\/rf2.txt","schmidt_nets\/rfpdf2.txt","schmidt_nets\/rf1.txt","schmidt_nets\/rfpdf1.txt","schmidt_nets\/rfpdf4.txt","schmidt_nets\/rf5.txt","schmidt_nets\/rf4.txt"],"gold_answer":"$\\begingroup$\n\nYou might try the [ RockFab package\n](https:\/\/cran.r-project.org\/web\/packages\/RockFab\/) . I am not a structural\ngeologist but I use other R packages for geological endevours.\n\n[ Documentation ](https:\/\/cran.r-project.org\/web\/packages\/RockFab\/RockFab.pdf)\n."}
{"query":"Generally speaking, iron is considered to be a very common resource. But I cannot find any evidence that there is any of it at all in New Guinea. Copper and gold, yes. Even nickel and cobalt. Iron on the nearby island of Bougainville. But no mention of iron.\r\n\r\nAre there really no useful iron deposits on the entire island? Or is it more like, there are some, just not big enough to make the news?","reasoning":"The island of New Guinea is divided into two entities: Papua New Guinea in the east and the Indonesian province of West New Guinea in the west. No known hard rock deposits of iron ore have been reported on the island. In Indonesia, the top five iron ore mines as of 2020 are the Yiwan Mine in South Kalimantan, the Gag Island Project in West Papua, the Pomalaa Mine in South East Sulawesi, the Pakal Island Mine in North Maluku, and the Nalo Baru Mine in Jambi. These mines produced varying amounts of iron ore in 2020.","id":"114","excluded_ids":["N\/A"],"gold_ids_long":["new_guinea_iron_ore\/pngs_orokolo_by_iron_sand_project_html.txt","new_guinea_iron_ore\/five_largest_iron_ore_mines_indonesia_2020.txt"],"gold_ids":["new_guinea_iron_ore\/pngs_orokolo_by_iron_sand_project_html3.txt","new_guinea_iron_ore\/five_largest_iron_ore_mines_indonesia_20202.txt","new_guinea_iron_ore\/five_largest_iron_ore_mines_indonesia_20201.txt","new_guinea_iron_ore\/five_largest_iron_ore_mines_indonesia_20203.txt"],"gold_answer":"$\\begingroup$\n\nThe island of New Guinea is effectively divided into two entities, the country\nof Papua New Guinea occupies the eastern half and the Indonesian province of\nWest New Guinea occupies the western half.\n\nNo known **hard rock deposits** of iron ore have been reported for anywhere on\nthe island.\n\nIn Indonesia, as of 2020, the [ top five iron ore mines ](https:\/\/www.mining-\ntechnology.com\/marketdata\/five-largest-iron-ore-mines-indonesia-2020\/) are:\n\n>   1. Yiwan Mine\n>\n\n>\n> The Yiwan Mine is located in South Kalimantan. It is owned by Yiwan\n> Mining.The mine produced an estimated 2.547 MTPA of iron ore in 2020.\n>\n>   2. Gag Island Project\n>\n\n>\n> Located in West Papua, the Gag Island Project is owned by Indonesia Asahan\n> Aluminium. The surface mine produced an estimated 1.06 MTPA of iron ore in\n> 2020. The mine will operate until 2047.\n>\n>   3. Pomalaa Mine\n>\n\n>\n> The Pomalaa Mine is located in South East Sulawesi. It is owned by Indonesia\n> Asahan Aluminium and produced an estimated 0.943 MTPA of iron ore in 2020.\n>\n>   4. Pakal Island Mine\n>\n\n>\n> The Pakal Island Mine, owned by Indonesia Asahan Aluminium, is a surface\n> mine located in North Maluku. The mine produced an estimated 0.515 MTPA of\n> iron ore in 2020.\n>\n>   5. Nalo Baru Mine\n>\n\n>\n> Owned by Earthstone Holdings, the Nalo Baru Mine is a surface mine located\n> in Jambi. It produced an estimated 0.027 MTPA of iron ore in 2020. The mine\n> will operate until 2031.\n\nAs you state in our question, there a small number of hard rock deposits on\nsmaller islands that are part of Papua New Guinea.\n\nThe only iron ore resource that occurs on the island of New Guinea are\ndeposits of [ iron sands ](https:\/\/mine.onepng.com\/2021\/11\/pngs-orokolo-by-\niron-sand-project.html) . They lie on the [ southern coast of PNG\n](https:\/\/mayurresources.com\/minerals\/) , around the coast of the Gulf of\nPapua. Currently, the main deposits are at Amazon Bay in the south east and\nOrokolo at the top of the gulf.\n\n[ ![enter image description here](https:\/\/i.sstatic.net\/1NJB1.png)\n](https:\/\/i.sstatic.net\/1NJB1.png)\n\nIt appears the iron sands are associated with other mineral sand minerals that\nare zircon rich, with some deposits having titanium and others vanadium. The\niron sands are composed of [ magnetite\n](https:\/\/en.wikipedia.org\/wiki\/Magnetite) ."}
{"query":"I am new with Python so please be kind. I want to download data from ERA5 and so far I have installed the CDS API package and followed all the instructions from https:\/\/cds.climate.copernicus.eu\/api-how-to\r\n\r\nI have my main file ready to use but I get an error about the configuration file. I know that this file should contain the following:\r\n\r\nurl: https:\/\/cds.climate.copernicus.eu\/api\/v2\r\nkey: {UID}:{key}\r\nverify:0\r\nI have created a text file and a configuration file with this info and I have placed them in the following address (as required by the error I get in python):\r\n\r\nC:\\Users\\username\\.cdsapirc\r\nHowever, I still get the same error. What I am doing wrong? Do I need to create a different type of file? Do I need to write the user info in a different way?\r\n\r\nException: Missing\/incomplete configuration file: C:\\Users\\username\/.cdsapirc\r\nBy the way, I'm using a windows computer.","reasoning":"Five steps to download the ERA5 data:Navigate to 'C:\\Users\\username' (or you can just move it later).\nIn Command Prompt, write 'type nul > .cdsapirc' and press Enter.\nRight-click the file and press 'Edit with Notepad++' (probably works with other programs).\nPaste the text that you already mentioned (key, etc).\nSave and close the document.","id":"115","excluded_ids":["N\/A"],"gold_ids_long":["era5_data\/Create_and_Delete_Files_and_Directories_from_Windows_Command_Prompt.txt"],"gold_ids":["era5_data\/Create_and_Delete_Files_and_Directories_from_Windows_Command_Prompt2.txt","era5_data\/Create_and_Delete_Files_and_Directories_from_Windows_Command_Prompt1.txt","era5_data\/Create_and_Delete_Files_and_Directories_from_Windows_Command_Prompt4.txt","era5_data\/Create_and_Delete_Files_and_Directories_from_Windows_Command_Prompt3.txt","era5_data\/Create_and_Delete_Files_and_Directories_from_Windows_Command_Prompt5.txt"],"gold_answer":"$\\begingroup$\n\nI had the same problem but have just found the solution after an hour or so of\ntrawling through forums! The problem was that the code 'api.py' could not find\nthe '.cdsapirc' file. The file type has to actually be 'CDSAPIRC' and not a\n'txt' file. The icon for the file will then be displayed in your folder as\nblank and the name will be '.cdsapirc'. I found the solution on here: [\nhttps:\/\/www.wikihow.com\/Create-and-Delete-Files-and-Directories-from-Windows-\nCommand-Prompt ](https:\/\/www.wikihow.com\/Create-and-Delete-Files-and-\nDirectories-from-Windows-Command-Prompt) . I created the file using the\nfollowing steps:\n\n  1. Navigate to 'C:\\Users\\username' (or you can just move it later). \n  2. In Command Prompt, write 'type nul > .cdsapirc' and press Enter. \n  3. Right-click the file and press 'Edit with Notepad++' (probably works with other programs). \n  4. Paste the text that you already mentioned (key, etc). \n  5. Save and close the document. \n\nHope that works :)"}