A New Explanation: Surface Air Pressure and Atmospheric Height | Knowledge about Earth | 20240726

This is Part 2 of my talks on Atmospheric Pressure near the Surface. The key basic issue is: does air pressure near the surface change with the surface temperature? Another seemly irrelevant issue is why the tropospheric height decreases from the equator to the two poles? It turned out that both issues are correlated and dependent of local surface temperature. Enjoy watching this new discovery!
It is often argued that the air pressure at near the surface can be calculated by adding the weight of all air molecules in a vertical column with cross-section 1 square meter.
6.It sounds plausible as, after all, each air molecule does have its weight due to the gravity, first formulated by Issac Newton. But the more you contemplate it, the more odd it would appear, as least it happened to me.
7.For liquids or other condensed matters, in which all molecules are closely packed one-by-one, or shoulder by shoulder. By way of contrast, air molecules are in random movements all the time, and, hence, can hardly have chance to exert an downward force together. So, it seems not very convincing that the total weight of spatially separated molecules be weighted, say, by an electronic balance like this.
8.Another question. If you look at this diagram for the global circulation, you will notice that the troposphere is getting thinner from the equator to poles. Why?
9.For quantify this phenomenon, I googled the relevant numbers. Here it is. “The height of the troposphere varies from the equator to the poles. At the equator it is around 11-12 miles (18-20 km) high, at 50 °N and 50 °S , 5½ miles and at the poles just under four miles high.” That’s to say, the thickness at poles is only one-third of that at the equator. So, this diagram is roughly accurate.
10.So the two questions were my concern last night. When I had my coffee this morning, it occurred to me that the two questions can be answered together by using an extrapolation method, similar to how Lord Kelvin deduced the absolute temperature scale in 1848 from systematic gas experiments.
11.Here are the details. First, imagine the surface temperature could be reduced near the absolute zero, zero K, similar to to the Bose-Einstein condensation, of course, it’s conceptually different, all thermal motions would stop and all air molecule would become condensed matter. And hence could be weighed. In this imagined scenario, everyone will be convinced that that the surface air pressure is the total weight of air molecules above the surface, due to mass conservation.
12.Second. We know the surface temperatures at the equator and a pole are about 300K and 200K, respectively. If I assume the dependence of the tropospheri height on the surface temperature is linear, and hence would be close to zero when the surface temperature is absolute zero, as shown by this blue line.
13.Unfortunately, the slop is too small compared with the trend line in green. By extrapolating the trend line toward lower temperature, as shown by this dashed green line, we can see the intercept is well above zero K. What does this mean?
14.Then I realized why. We know nearly 80% air is made by nitrogen. And liquid nitrogen is 77K, I knew this quite well as I often used liquid nitrogen and liquid helium to do magnetic resonance spectroscopic experiments in the 90s. This implies air would almost become liquid around 77K.
15.Indeed, the intercept is close to 77K! What at So I replaced the first straight line by this linear equation by assuming the thickness of troposphere near the equator is 16 km.
17.Where H represents altitude in km and T is temperature in Kelvin. Notice the slop simply means if the surface temperature increases 1K, the thickness of the troposphere would increase about 70 meter.
18.If so, can this number be explained by basic law in physics? Before my coffee getting cold, I used this pen to work out this explanation.
19.The linear dependence of the height, or the thickness, of troposphere on temperature in Kelvin implies both sides of the equation may represent energies of different types, because kT is how much energy each degree of freedom in an air molecule can have in thermodynamics, where k is Boltzmann constant.
20.Obviously, the constraint for the atmospheric height is caused by gravity, Newton’s gravity, not Einstein’s geometric curvatures. Therefore, it is reasonable to make the left-hand side as gravitational potential energy.
21.Consider one mole air with its mass 29 g in an imagined thin layer at height H. How could the air molecule move that high from the surface? By directly transforming its kinetic energy gained near the surface into gravitational potential energy, or through multiple relay processes.

[@RodMartinJr]

Outstanding. My thesis on *_Thick Atmosphere as a Thermal Reservoir_* overlaps the topic of this video quite nicely. And my study comparing the same pressure range at the top of 7 tropospheres (Venus, Earth, Jupiter, Saturn, Titan, Uranus, and Neptune) suggests that the temperature at 1 atmosphere of pressure is ONLY due to factors excluding the greenhouse effect. "The results of this study reinforce the fact that the PEAL for any thick-atmosphere world will have an amount of energy stored in its mass which depends only on insolation, albedo, specific heat, and the mass of the atmospheric column" (where "PEAL" means Pressure Equivalent Atmospheric Layer). The implications of these effects on the potential for terraforming are quite profound. I explore this in my book, *_Terraforming Mars: Remaking the Red Planet, Ready for Life._* 😎♥✝🇺🇸💯

[@mplaw77]

This book has a chapter devoted to air pressure at 1 bar and 0.1, showing the temperatures above the Blackbody temperatures for the 7 gaseous planets. Mars was left out due to even lower surface pressure. The graphic and values of pressure in Bar vs K is from a NASA publication that has since disappeared from the NASA site or has been buried because this raised questions about the CO2 narrative. The book is found on Amazon in Kindle format, and I found a newly printed paperback copy by searching the internet. It was first published 2011, also available in Google ebooks. This book is an elementary treatment in terms of math, but it does show in detail how calculations are made and explains radiative transport, and it has many examples. BOOK: " Slaying the Sky Dragon - Death of the Greenhouse Gas Theory Kindle Edition by John O'Sullivan (Author), & 7 more Format: Kindle Edition Even before publication, Slaying the Sky Dragon was destined to be the benchmark for future generations of climate researchers. This is the world's first and only full volume refutation of the greenhouse gas theory of man-made global warming. Nine leading international experts methodically expose how willful fakery and outright incompetence were hidden within the politicized realm of government climatology. Applying a thoughtful and sympathetic writing style, the authors help even the untrained mind to navigate the maze of atmospheric thermodynamics. Step-by-step the reader is shown why the so-called greenhouse effect cannot possibly exist in nature. By deft statistical analysis the cornerstones of climate equations - incorrectly calculated by an incredible factor of three - are exposed then shattered.

[@canberroo2509]

Dr Ned Nikolov came to a very similar conclusion a few years back by analyzing the estimated surface temperatures of various solar system bodies and comparing that to their relative atmospheric pressures. Strong correlation - the higher the atmospheric pressure the higher the average surface temperature and vice versa. Of course he was scorned and derided by the climate cult enforcement bureau. Very interesting. Thank you.

[@mplaw77]

NASA posted measured values for the gaseous planets temperature K vs pressure in bar excluding Mars as its atmosphere is just to thin. They showed the temperature above the blackbody temperatures in K calculate. At 1 bar Venus high from the surface was around 350 K, this from memory so i purposely shot high , Venus at the surface was 90 bar and about 738 K. Do not bother looking it disappeared about Feb 2021 with Biden admin. going 5 fire bells alarmist, they removed it or buried it

[@andymcculloch9199]

Excellent work! Also a concise description of how you worked it out.

[@eagle43257]

Thank you very much Dr Yong. We learned a lot

[@stevetitcombe939]

I think you've made real progress here. Please can you provide the reference to your earlier video and provide details of the Commentator's comments that inspired this latest video?

[@yongtuition]

Here it is: kzbin.info/www/bejne/ZpTcmqBmdrmHeKM The viewer is Uwe Sendner.

[@reinerwilhelms-tricarico344]

Simple question: shouldn’t the density of air near the surface be considerably lower near the equator than near the poles? In other words, there should be more air molecules (O2, N2, H2O, CO2 …) in a cubic meter of air near the poles than near the equator. This should be measurable by direct weight measurements: comparing the weight of an air filled large container with its weight when evacuated. Also: the speed of sound is considerably slower near the poles than near the equator. The speed of sound C is proportional to Sqrt[1.4 x Pressure/Density]. (the 1.4 is the adiabatic index of air). C is about 340 meters/second near the equator, and more like 315 m/s when it's really cold (-20 degrees C).

[@marcossouza4872]

Beautifully explained.

[@ronb7481]

Excellent, as always.

[@natterlynabob1472]

Yes! Pressure determines temperature and not the other way around! That explains a lot.

[@reinerwilhelms-tricarico344]

yes but pressure is also energy density (just check the units: N/m^2 is the same as Nm/m^3, which is energy per volume). And while the so-called average global temperature makes little sense, it is still true that there is now more energy in the atmosphere, which is responsible for more storms.

[@fredneecher1746]

@@reinerwilhelms-tricarico344 More energy in the system would result in more everything, not just storms. But specific weather events will still require specific local conditions, and storms are no exception.

[@natterlynabob1472]

@@reinerwilhelms-tricarico344 Been through this before right here. Storms come from temperature *differences* not the energy itself. The result of global warming is to change the temperature distribution and *reduce* those differences.

[@Tengooda]

natterly: You claim, "Pressure determines temperature and not the other way around!" The warm surface continually radiates heat to space. How does pressure, that is ~ unchanginging, generate that energy?

[@natterlynabob1472]

@@Tengooda You have not been following Dr. Yong's podcasts. Radiation from the warm surface is almost 100% absorbed near the surface. None of it radiates into space.

[@Tengooda]

Yong claims, "air molecules are in random movements all the time and HENCE [my emphasis] can hardly have a chance to exert a downward force together". Complete nonsense. Air molecules are in random movements all the time and THEREFORE exert pressure (a force per unit area) in ALL directions, (including downward) due to collisions of those molecules with whatever surface with which they interact.

[@Quroxify]

Thanks for this delightful intuitive perspective. I appreciate your way of examining all ideas without prejudice. I've always wondered what goes on with the column of air reaching from the surface to.... ??? Where exactly does it no longer hold down the column. These are competing drivers of molecules in the atmosphere. Gravity, down towards the center of the sphere earth. Centrifugal force outward directed away from the axis of rotation. Coriolis force ( a form of inertia) directed in the opposite direction of the summation of other forces. Buoyancy, the lessening of density compared to surrounding parcels of air. Expansion due to adiabatic cooling upon rising. And acquired gravitational potential energy as molecules absorb heat from surrounding molecules and have upward trajectory by random chance.

[@firstlast-ty4di]

Thank you for the update.

[@randytucker3083]

Wonderful work, Great new tools for research!

[@stevetitcombe939]

If the "back radiation induced by radiative greenhouse gas" hypothesis were really true then, on a cloudless day, the incoming (downwelling) radiative energy spectra comprising UV, visible, IR and LWIR energy spectra from solar insolation and the LWIR energy spectra from Greenhouse Gas induced back-radiation being received by the Earth's (day-time) surface would not be expected to show any attenuation of those electromagnetic frequencies that are specifically associated with the absorbtion of the various LWIR-active molecules that are, indeed, present in our atmosphere. If it were true that the back radiation induced by Greenhouse gases are responsible for the enhanced warming of the Earth's surface then surely we would expect to see MORE electromagnetic energy in these specific wavelengths to be received by Earth's surface, rather than less. Don't get me wrong: I do believe that LWIR-active gas molecules intercept LWIR-energy from within the solar insolation and also intercept LWIR-energy that's emitted (upwelling) from the Earth's surface but I strongly suspect that the vast majority of this energy is not re-emitted as a new LWIR photon as is argued by the proponents of back radiation but is, instead, converted to translational kinectic energy when the 'excited' LWIR-active gas molecule collides with another gas molecule in the atmosphere. It is by this means that additional translationsl kinetic energy (represented as increased pressure and hence temperature) gets into our atmosphere, particularly near the Earth's surface where the molecular density is greatest and the average molecular speed is greatest so that the mean free time available for photon re-emission is smallest. In the upper paet of the troposhere, density and molecular speedis less, so more time is available for re-emission of the new LWIR photon. Of the additional kinetic energy in the atmosphere, some will be converted to gravitational potential energy as the tropopause height increases. For this reason, not all of the LWIR energy being absorbed by the LWIR-active gas molecules will result in an increase in the near-surface air temperature, as some of this energy will be converted to gravitational potential energy whilst some will be re-emitted as a photon into space and a very small amount will be re-emitted as a photon to be thermalised upon Earth's surface. An interesting experiment would be to measure the electromagnetic radiation being received by the Earth's surface i.e. the Zenith observation, at midnight on a CLOUDLESS night when the new Moon has not yet risen in the night-time sky - we would then be able to measure amount the back radiation across the varous electromagnetic frequencies that are specifically associated with photon re-emission by LWIR-active molecules. Personally, I don't doubt that there will be some energy seen in those specific frequencies. But what I'm now 'betting the farm on' is that the energy flux density levels (measured in units of W.m^-2) of those specific frequencies that are associated with the LWIR-active molecules such as CH4, H2O and CO2 are nowhere near the level being claimed to be warming the entire surface of the planet in order to generate the mythical 'forcings' needed to raise the near-surface air temperature of the entire planet from the 255K to 288K. It is not radiative energy transfer that is responsible for Earth's near surface atmospheric temperature of 288K, rather it is predominantly due to surface advection/convection. Once the kinetic energy taken from the day-side hot surface is in the lower atmosphere some is converted, vertically, into gravitational potential energy (represented by the adiabatic lapse rate) to maintain the height of the tropopause and some is conveyed (still as kinetic energy) horizontally by differences in air pressure (from high pressure regions to low pressure regions)

[@kevinhachton9649]

With respect to the IR active gases back radiation, it can't indeed warm the surface because this downward flux is smaller than the upward flux emitted by the surface (see the Earth Annual Mean Energy Budget, NASA 2009 for example) : - the radiative energy transfer between the surface and the atmosphere in the IR spectrum is the difference between the IR upward flux emitted by the surface and the backward flux emitted by the atmosphere. This difference is positive (some 20 W/m² according to the Earth energy budget). So it is the surface which can radiatively warm the atmosphere (with the fraction of the transfered radiative energy which is converted to kinetic energy). - those 20W/m² of absorption/transfer by the active gases in the IR spectrum may be compared to the 160 W/m² those same gases emit into space (according to the Earth energy budget), - the conclusion is that with the contributrion of the convection/advection process, and assuming that all the transfered radiative energy of 20W/m² is transformed in kinetic energy, those gases cool the atmosphere system by a net dissipation of some 140W/m² and as seen before, they don't warm the surface either.

[@C_R_O_M________]

In addition to what you presented here (thanks for the provoking thoughts) I thought that centrifugal forces are exerted to a greater degree near the equator vs the poles (and the atmosphere gets affected by that force) and this could also explain the height differences of the troposphere near the equator and the poles. Sure enough, I found sources that maintain the same idea.

[@yongtuition]

Thank you for you comments. The direction of centrafugal forces are perpendicular to the rotation axis whist the gravity is toward the centre of the earth. So, the tropospheric thickness near the equator would be affected most.

[@C_R_O_M________]

@@yongtuition so both forces apply, right?

[@yongtuition]

@@C_R_O_M________ The centrifugal force is much weak. In terms of acceleration, gravity is 9.8 whilst centrifugal at the equator is just 0.033. (m/s^2)

[@Quroxify]

That was my thought too. Now I see the estimate of centrifugal force to be small compared to gravity. Looking at the case of the (oceanic) tidal bulge, it is explained, not to be the direct gravitational attraction of the moon on the water but due to the resolved component in the tangential direction. Might it be a similar effect with regards to the atmosphere? That is, a component in the direction perpendicular to the axis of rotation resolves into a component normal to the surface and one tangential to it. The net affect on a non solid is that everything slides in the direction of the equator. I didn't yet see an explanation of the phenomena. @yong ?

[@daNorse]

Young, thanks for this lecture. It is a bit academic, but if can you explain this so that ordinary people can understand it, that would be very helpful. Example is Happer's explanation of the logaritmic effect of CO2 blocking IR in the 15 micron band: "Doubling CO2 is like a second layer of red paint on the barn will not make much difference."

[@Tengooda]

Doubling CO2 is NOT like a second layer of red paint on the barn - that is a poor analogy. Multiple independent lines of evidence show that doubling atmospheric CO2 causes an average global surface temperature rise of around 3degC. That would make a huge difference to life on Earth and sea level. Happer's apparent lack of understanding of climate science is legendary. He has no credibility amongst climate scientists.

[@qa1e2r4]

This is great explanation. The surface temperature is based on the atmospheric pressure above it. Brilliant! Thank god earth keeps sucking the atmosphere from moon, Venus and Mars or otherwise we will be still in an ice age.

[@kassandralehming9641]

many meteorologists will be dismayed to learn that they have it exactly backwards! For decades, it has been understood that when the surface of the Earth heats the air above it, that volume of air becomes less dense and is pushed upwards by adjacent volumes of denser air converging horizontally. These air volumes are subsequently warmed, expand and rise just as happened previously, resulting in what is known as an area of LOW pressure. Meanwhile, the air that is moving laterally at the Earth's surface towards the column of rising air is replaced by descending air above it; this is known as an area of high pressure. Now, the column of rising air is cooling as it ascends but it is still warmer and less dense than the adjacent air, so it piles up higher than the air around it and spills over sideways in diverging flows, which can, obviously, feed into the columns of descending air. When we talk about high and low pressure, it is with reference to the force applied from above to the surface or a specific altitude above the surface; we do not confuse it with the strength of air flows at the top of the atmosphere. By contrast, if we had a rigid, closed tank 20 km long, we would find the pressure to be equal at any and every point. Also, when I pump up my bicycle tire to 50 psi, there is some heat apparent but when it cools down the increased pressure doesn't continue to give off heat. That's because it is caused by pushing more molecules into the tire, not by applying heat.

[@BCarli1395]

Thank you.

[@YiOughta]

Why does condensed, thick and heavy cold air pour in my window in winter. Heated air with all it energy doesn't stand a chance and is easily moved.

[@mossig]

The warm air rises. It goes out much faster through ventilation ducts or a chimney when you open up a window. Same thing happens if you burn something inside, then cold air has to replace the hot air escaping.

[@reinerwilhelms-tricarico344]

Hold a candle under the window and you'll see where the cold air comes in. It literally drops down. Then hold the candle higher up and you might see where warmer air leaves the room.

[@YiOughta]

@@reinerwilhelms-tricarico344 the video is talking about high/low pressure of air masses. I suggest that cold dense air simply weights more by volume than hot air and is therefore pushing down on the surface with more force than expanding hot air that wants to rise. In a room, is not like outside, where there is nothing to contain expansion

[@FelonyVideos]

Rough observation: When you reach 15psi in the venuvian atmosphere, the temperature is roughly the same as Earth. That same would apply on Mars, if you dug a one mile deep hole at its lowest point, so as to achieve 15 psi. There is a modest adjustment to account for the distances to the Sun, but its not a lot, compared to the pressure predicts temperature relationship. Venus' and Mars' atmospheres are almost 100% CO2. So much for greenhouse gas warming. 😂

[@ingridschmall3289]

Was ist mit der kinetischen Energie der Luftmoleküle, die durch Stossprozesse Druck ausüben?

[@yongtuition]

The kinetic energy of air molecules makes the atmosphere thicker or taller, but the surface air pressure remains a constant.

[@ingridschmall3289]

@@yongtuition energiereichere Luftmoleküle können doch mehr Energie auf die Erdoberfläche übertragen, und so mehr Druck ausüben, oder?

[@mossig]

And what caused the 20 meter increase?

[@reinerwilhelms-tricarico344]

More energy in the atmosphere: CO2 results in more energy retained in the atmosphere, shifting the radiation balance up. But it's also Okay to say because of higher temperature, since there is a direct relationship between average kinetic energy and temperature: E = (3/2) k T (k is the Boltzmann constant). The energy here is due to the movements of air molecules. This equation doesn't necessarily mean that E is a function of T. It could be said it's the other way round. Energy is more fundamental, while thermodynamic temperatures is derived macroscopically (temperature makes little sense for an individual molecule) See: en.wikipedia.org/wiki/Thermodynamic_temperature

[@mossig]

​@@reinerwilhelms-tricarico344 That sounds like the chicken and the egg conundrum! What came first? Heat increased the atmosphere or the atmosphere increased the heat. It's definitely not the Co2. It's a trace gas at something like 40 ppm and two thirds of it is oxygene in the molecule. 13.3 ppm of carbon can't hold even the tiniest energy, it will radiate away immediately also.

[@janne9034]

Cool cool, but I am interested in flying dinosaurses. Was air pressure higher back then 100 million years ago - as in troposphere being thicker? Did that help with the flying? Or was it the higher oxygen content, that made the dinosauruses strong? Solar wind blows away air all the time. In 100 million years it is significant loss of molecules. Conclusion with this theory of Yong Tuition suggests that the air pressure was the same as it is today. Dinosauruses were strong.

[@blshouse]

And now Venus makes sense.

[@yongtuition]

Tell us more in detail, please.

[@brendanward2991]

@@yongtuition Tony Heller put out a video recently arguing that the high surface temperatures on Venus were a consequence of the high atmospheric pressure and not due to any runaway greenhouse effect.

[@ingridschmall3289]

1:44: was ist mit dem Gravitationsfeld der Erde? An den Polen ist es doch stärke.

[@yongtuition]

Yes, gravitational field strenght is stronger at the poles. So, the surface air pressure near the polses is higher than that near the equator if the air mass per unity column is the same.

[@ingridschmall3289]

@@yongtuition Ist the air mass per unity column the same?

[@tangoone6312]

.

[@MIIIM-7]

#InFraUniAxiomfacebook

[@MIIIM-7]

Thank you, it is a huge improvement to my models' precision