Guest Post by Willis Eschenbach
Over at the Notrickszone, there’s much buzz over a new paper entitled Molar Mass Version of the Ideal Gas Law Points to a Very Low Climate Sensitivity, by Robert Holmes. The Notrickszone article is headlined with the following quotation from the paper:
“In particular, formula 5 (and 6) as presented here, totally rules out any possibility that a 33°C greenhouse effect of the type proposed by the IPCC in their reports can exist in the real atmosphere.”
– Holmes, 2017
And here’s the abstract:
Abstract: It has always been complicated mathematically, to calculate the average near surface atmospheric temperature on planetary bodies with a thick atmosphere. Usually, the Stefan Boltzmann (S-B) black body law is used to provide the effective temperature, then debate arises about the size or relevance of additional factors, including the ‘greenhouse effect’. Presented here is a simple and reliable method of accurately calculating the average near surface atmospheric temperature on planetary bodies which possess a surface atmospheric pressure of over 10kPa.
This method requires a gas constant and the knowledge of only three gas parameters; the average near-surface atmospheric pressure, the average near surface atmospheric density and the average mean molar mass of the near-surface atmosphere. The formula used is the molar version of the ideal gas law. It is here demonstrated that the information contained in just these three gas parameters alone is an extremely accurate predictor of atmospheric temperatures on planets with atmospheres >10kPa. This indicates that all information on the effective plus the residual near-surface atmospheric temperature on planetary bodies with thick atmospheres, is automatically ‘baked-in’ to the three mentioned gas parameters.
Given this, it is shown that no one gas has an anomalous effect on atmospheric temperatures that is significantly more than any other gas. In short; there can be no 33°C ‘greenhouse effect’ on Earth, or any significant ‘greenhouse effect’ on any other planetary body with an atmosphere of >10kPa.
Instead, it is a postulate of this hypothesis that the residual temperature difference of 33°C between the S-B effective temperature and the measured near-surface temperature is actually caused by adiabatic auto-compression.
Dang … “adiabatic auto-compression” as a permanent energy source. Is it patented yet?
Please forgive my sarcasm, I just get tired of endless claims of endless energy … onwards. Here is a look at the various planetary atmospheres:
And finally, here is his math that leads to his mystery formula. From the paper:
Molar Mass Version of Ideal Gas Law Calculates
Planetary Surface Temperatures
The ideal gas law may be used to more accurately determine surface temperatures of planets with thick atmospheres than the S-B black body law [4], if a density term is added; and if kg/m³ is used for density instead of gms/m³, the volume term V may be dropped. This formula then may be known as the molar mass version of the ideal gas law. The ideal gas law is;
P V = n R T (1)
Convert to molar mass;
P V = m/M R T (2)
Convert to density;
PM / RT = m / V = ρ (3)
Drop the volume, find for density;
ρ = P / (R T / M) (4)
Find for temperature;
T = P / (R ρ/M) (5)
[VARIABLES]
V = volume
m = mass
n = number of moles
T = near-surface atmospheric temperature in Kelvin
P = near-surface atmospheric pressure in kPa
R = gas constant (m³, kPa, kelvin⁻¹, mol⁻¹) = 8.314
ρ = near-surface atmospheric density in kg/m³
M = near-surface atmospheric mean molar mass gm/mol⁻¹
Now, I agree with all of that. Well, other than the strange form of the last equation, Equation 5. I’d simplify it to
T =P M / (ρ R) (5)
But that’s just mathematical nitpicking. The underlying math is correct. That’s not the problem. The problem is where it goes from there. The author makes the following claim:
In short, the hypothesis being put forward here, is that in the case of Earth, solar insolation provides the ‘first’ 255 Kelvin – in accordance with the black body law [11]. Then adiabatic auto-compression provides the ‘other’ 33 Kelvin, to arrive at the known and measured average global temperature of 288 Kelvin. The ‘other’ 33 Kelvin cannot be provided by the greenhouse effect, because if it was, the molar mass version of the ideal gas law could not then work to accurately calculate planetary temperatures, as it clearly does here.
I’m sorry, but the author has not demonstrated what he claims.
All that Robert Holmes has shown is that the atmospheres of various planets obey, to a good approximation, the Ideal Gas Law.
… So what?
I mean that quite seriously. So what? In fact, it would be a huge shock if planetary atmospheres did NOT generally obey the Ideal Gas Law. After all, they’re gases, and it’s not just a good idea. It’s a Law …
But that says exactly NOTHING about the trajectory or the inputs that got those planetary atmospheres to their final condition. Whether the planet is warmed by the sun or by internal radioactivity or whether the warming is increased by GHGs is NOT determinable from the fact that the atmospheres obey the Ideal Gas Law. They will ALWAYS generally obey the Ideal Gas Law, no matter how they are heated.
And more to the point, this does NOT show that greenhouse gases don’t do anything, as he incorrectly claims in the above quote.
Look, we could start up ten million nuclear reactors and vent all their heat to the atmosphere. The planet would assuredly get warmer … but the atmosphere wouldn’t stop obeying the Ideal Gas Law. The variables of density and temperature and mean near-surface atmospheric molar mass would simply readjust to the new reality and the Ideal Gas Law would still be satisfied. You could still use his Equation 5 version of the Ideal Gas Law to calculate the temperature from the other variables, regardless of whether or not the atmosphere is heated by nuclear reactors.
So I’m sorry, but the underlying premise of this paper is wrong. Yes, planetary atmospheres generally obey the Ideal Gas Law, duh, why wouldn’t they … and no, that doesn’t mean that you can diagnose or rule out heating processes simply because the atmosphere obeys the Ideal Gas Law. They will always obey the law regardless of how they are heated, so you can’t rule out anything.
Best of another sunny day to everyone,
w.
MY USUAL POLITE REQUEST: When you comment, please QUOTE THE EXACT WORDS YOU ARE TALKING ABOUT so we can all understand what you have an issue with.
The ideal gas law does not say that if you raise p, you will raise T (at V = const) – it depends on the change in the amount of the gas (n or m) or density. The temperature rise is not a consequence of ideal gas law, but from the compression work and the pumping process not being slow enough to be isothermal. When the tire (and the air inside) cools to ambient temperature after the pumping, p will decrease too, according to ideal gas law p1/p2=n1/n2=ρ1/ρ2
Ideal gas law is just an equation of state, which links the three state variables: temperature, pressure and density. If any two of them are known, the third is given (fixed) by the gas law.
This was a reply to the first comment by ristvan.
My post at Feb 7th 2.00 am seems to have hit the spam filter for some reason. Hope it gets through shortly.
You have to look at the atmosphere as a system of molecules bouncing around. The 33K greenhouse effect is only at the surface, the average temp of the whole atmosphere is still only the black body temp, when measured at the center of mass of the atmosphere, where the air pressure is 1/2 the surface pressure. On Earth with it’s weak amount of CO2 and on Venus with it’s overwhelming amount of CO2, that’s the case, and shows that gh gases aren’t a major factor. If gh gases are a major factor then why is Venus’ average atmospheric temp over the whole volume only the black body temp?
Venus has a much denser atm than Earth.
Willis said:
“Whether the planet is warmed by the sun or by internal radioactivity or whether the warming is increased by GHGs is NOT determinable from the fact that the atmospheres obey the Ideal Gas Law. They will ALWAYS generally obey the Ideal Gas Law, no matter how they are heated.
And more to the point, this does NOT show that greenhouse gases don’t do anything, as he incorrectly claims in the above quote.”
Which is correct on the face of it BUT the point is that if GHGs were able to alter surface temperature or atmospheric density without altering gravity or atmospheric mass then the atmosphere would go out of hydrostatic equilibrium and be lost either by falling to the surface or by drifting off into space.
For example:
If one starts with a GHG free atmosphere in hydrostatic equilibrium then the downward force of gravity is on average exactly offset by the upward pressure gradient force caused by surface heating via conduction and convection. That balance must apply at every height for an atmosphere to be retained.
If one then adds GHGs so as to raise surface temperature and thereby reduce surface density then the consequent expansion of the atmosphere would create a topmost layer where the upward force exceeds the downward force and that layer would be lost to space.
Losing the topmost layer would reduce total atmospheric mass so that the same surface temperature would push the reduced weight of the atmosphere a little higher again to replace the lost layer and again the renewed topmost layer would have the upward force exceeding the downward force and it would be lost in turn.
And so on until there is no atmosphere.
So, by applying basic physics it is implicit that GHGs don’t do anything to surface temperature.
SW says: “If one starts with a GHG free atmosphere in hydrostatic equilibrium then the downward force of gravity is on average exactly offset by the upward pressure gradient force caused by surface heating via conduction and convection. That balance must apply at every height for an atmosphere to be retained.”
That, I think, is the gist of it.
My basic conclusion (so far) is that the compression caused by gravity must affect the heat capacity of parcels of air nearest the surface, since those parcels are under about 19,000 pounds/ square yards of pressure. Expressing the pressure in square yards I think makes it clearer how much pressure really is bearing down on us, even now. This dynamic between gravity and convection/conduction seems to be a logical and elegant way to express the lapse rate, so I don’t see that the GHGs add much of anything to this basic mechanism.
If we had no GHGs, would the mechanism that Wilde described still hold? Yes. Why would it not? If we don’t need GHGs to describe the lapse rate, why would we need them to describe why the surface isn’t radiating away at 255K?
Don asks: ”If we had no GHGs, would the mechanism that Wilde described still hold?”
The mechanism described by Stephen doesn’t hold with or without GHGs. That mechanism is but Stephen’s imagination at work. To lose an atm. in real life, escape velocity for the atm. constituents must be exceeded & is a fact Stephen doesn’t mention. H2 at Earthian temperatures is light enough to reach escape velocity so that part of the atm. HAS escaped & there is very little original H2 left. Same for a lot of the original helium.
”If we don’t need GHGs to describe the lapse rate, why would we need them to describe why the surface isn’t radiating away at 255K?”
Because the adiabatic lapse derivation assumes temperature changes slow enough with increasing z height so calculations work out only g and total Cp needed in the calculation. Since O2,N2 make up almost all the air Cp, the rest don’t make much difference.
Where GHGs matter is the z=0 value for temperature to start lapsing from. The standard atm. for the midlatitude tropics shows this start temperature inclusive of all the natural GHG effects at the time standard lapse was developed. Reduce the GHGs and you reduce the temperature at z=0 but do not affect the adiabatic lapse since g and Cp don’t change (much) as GHGs change.
Conversely, increase the GHGs and you increase the start z=0 temperature but do not affect the adiabatic lapse since g and Cp don’t change (much). As long as the increased temperature doesn’t change much with increasing z.
Trick says: “Where GHGs matter is the z=0 value for temperature to start lapsing from.”
Yes that’s the theory, isn’t it? But then you agree that what raises the earth’s surface temp from 255K to 288K is gravity and pressure and atmospheric density, without any need to consider GHGs? Because you say, “the adiabatic lapse derivation assumes temperature changes slow enough with increasing z height so calculations work out only g and total Cp needed in the calculation. Since O2,N2 make up almost all the air Cp, the rest don’t make much difference.”
Has this z value movement, caused by GHG, been measured? Is it real or theoretical?
You say, “Reduce the GHGs and you reduce the temperature at z=0 but do not affect the adiabatic lapse since g and Cp don’t change (much) as GHGs change.” But I believe this confuses what you said earlier; it isn’t that the temperature at z changes, it’s that z itself, the emissions height, changes, while the temperature stays the same and the lapse rate proceeds from there. But, I don’t buy that GHGs affect the lapse rate nearly as much as the theory holds.
I don’t think anyone has effectively refuted the very simple logic that Wilde has laid out: “If one starts with a GHG free atmosphere in hydrostatic equilibrium then the downward force of gravity is on average exactly offset by the upward pressure gradient force caused by surface heating via conduction and convection. That balance must apply at every height for an atmosphere to be retained.” I believe people need to think about this more instead of immediately pondering ways to refute it. He has described the lapse rate elegantly, and with no need for GHGs. If it seems not to make sense, then maybe thinking about the actual pressure bearing down on the surface atmosphere will help it make sense; this pressure is not trivial.
”But then you agree that what raises the earth’s surface temp from 255K to 288K is gravity and pressure and atmospheric density, without any need to consider GHGs?”
Do not agree. The sun raises the avg. near surface T from 255K to 288K as GHG parameters alone are increased from zero to natural amounts by formally tested basic atm. physics.
Once you know avg. density(0) and avg. P(0) either at avg. 255K or 288K then the associated avg. T can be ideally computed from IGL. The problem is measuring the avg. P and avg. density to begin with. The other approach, energy balance, also works fine to get avg. T but you need planetary measurements also.
Today it seems easy, but before the NASA probes there were only estimates for the other planets avg. T, some were remarkably close others not so much. Earth already had measured surface avg. T, avg. P so could ~calculate Earth avg. density.
As far as refuting Wilde, nothing he writes gets the atm. constituents up to escape velocity, the temperatures aren’t high enough for heavy N2, O2 et. al. molecules. If below escape velocity, molecules and atm. are retained. Pretty sure Wilde can not even compute escape velocity for a certain molecule, never have seen him write a formula for that, for anything btw.
“If we had no GHGs, would the mechanism that Wilde described still hold? Yes. Why would it not? If we don’t need GHGs to describe the lapse rate, why would we need them to describe why the surface isn’t radiating away at 255K?”
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Good points here Don.
We certainly don’t need GHG to describe the lapse rate (or auto-compression as I call it) why would we?
All the 6 surfaces in my room are emitting 390 Watts. What is the temperature in the centre?
(6 x 390)/6.
It says above he sun is providing 255 Watts and we have to find a further 33 Watts to get 288 Watts.. So (255 +X)/2 = 288.
x = 576 – 255 or x =321 Watts. To get 288 Watts you need a second source of 321 Watts in addition to Suns 255 Watts.
Am I doing something wrong?.
Just realised it’s 288K
To The Reverend Badger;
Yours is the most concise and elegant explanation I have seen in support of the conclusions in my paper. Well Done!
Robert,
May I refer you to this?:
https://tallbloke.wordpress.com/2017/06/15/stephen-wilde-how-conduction-and-convection-cause-a-greenhouse-effect-arising-from-atmospheric-mass/
Stephen
Thanks for the link.
Your material makes perfect sense to me.
I think the key point is this;
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“So is it atmospheric mass returning kinetic energy to the surface (retrieved from potential energy in descent) or is it DWIR that causes the greenhouse effect. It cannot be both.”
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Indeed it cannot be both, and I am pretty sure that it is the former.
Robert – you are too kind. I grasp the logic sort of intuitively then try to check it myself bit by bit. My thought experiment of 2 planets one with GHG and one without is one I have had for years. Trying it out on some of the physics PhDs and one NASA scientist in the Stack-Exchange forum sort of confirmed the BS of CAGW as they never answered even the simplest of questions, just danced around it, posted dozens of graphs and told me I was asking the wrong question. When the moderators actually warned me I might be asked to leave as my posts were “unpopular” it really hit home.
There has been a fair bit of “dancing around” in this thread. The culprits know who they are – enough said!
If someone asks me a question about atmospheric physics and what I think I will try to answer it honestly provided they do it politely and accord me the same respect. Those who are rude,evasive and unhelpful here on WUWT are not furthering the cause of increasing our understanding of this subject.
Your paper is, I suspect, not the whole story but is sufficient to entirely refute the GHG theory. It adds some insight into how the atmosphere really works but the end answer will possibly incorporate something from Stephen Wilde, Nikolov and Zeller and D**g C****n (Ask Anthony about the *** if you don’t know). All of you guys should be working together ideally but for now make sure you all read one another’s work in great detail and with careful consideration. The truth will gradually coalesce.
Rev B,
My description is simple and complete and needs nothing more from others.
Good job.
“Dang … “adiabatic auto-compression” as a permanent energy source. Is it patented yet?
Please forgive my sarcasm, I just get tired of endless claims of endless energy … onwards. Here is a look at the various planetary atmospheres:”
So called adiabatic auto compression is not a permanent energy source but it is an energy store.
It is a closed loop of (originally solar) energy captured via conduction by the system of convective overturning which developed within the atmosphere during the period of time that the atmosphere first formed.
It can never be radiated to space until the sun is switched off whereupon the gases in the atmosphere will fall to the ground as frozen solids.
Gravity “traps” solar energy on this planet and every other planetary body with an atmosphere, not greenhouse gasses, which make little or no contribution to the temperature at the surface. This is the atmospheric thermal effect described by https://twitter.com/NikolovScience.
Might have been a bad idea for Anthony to put this under the ‘bad science’ section 🙂
Mi casa su casa.
This is under the ‘bad science’ section!
You are kidding – right?
Not kidding. Look at the home page and go to your article or click here:
https://wattsupwiththat.com/category/bad-science/
HAHAHA I am in with the ‘shrinking beetles’, the ‘conceptual penis’ and other ‘crackpots’ like Svensmark and Shaviv!!!
That is so funny!
One has to laugh.
Anthony pulled a similar one on me when I wrote a post pointing out that the Trenberth diagram was wrong because it omitted energy returning to KE from PE beneath descending columns of air but I put up with some mockery because at least he had the courage to publish it.
Your work amongst that of others is proving me to have been right.
And he has the old Climate Realists site where I first contributed listed under the ‘Transcendent Rant and Way Out There theory’ section.
Maybe he should reconsider?
We live in a world where an accurate and provable description of reality, is called ‘Bad Science’ or ‘Way Out There Theory’ – not on mainstream sites (which would be bad enough), but on skeptical sites!
I am honestly still laughing!!
You have 100% made my day mate!
If the lapse rate is created by the greenhouse effect why can it be calculated with reference only to physical properties and no reference to radiant properties at any point? If the surface temperature is dependent on downwelling LW radiation why can the spot temperature at any point be calculated with no reference to the LW radiation only incoming SW radiation? If DWLR in excess of the incoming energy from the sun really can raise the temperature of the earth’s surface then why can’t we measure that ability to do so or recover that energy if it is real?
Extrapolate out the 2 slopes to see where they intersect the rapid increase that was sunrise, that’s just the change to stay above dew point temp.
A 35W/m^2 drop in net outgoing, oh, it has to add 35W/m^2 up too!
You are looking at internal eddies in the system. The issue is how to compute the mean temperature of a planet with an atmosphere which — sky dragon-denier insults aside — can be done without reference to the composition of that atmosphere. All things being equal a planet with a higher atmospheric pressure will have a higher mean temperature at the surface. That is irrespective of the composition of that atmosphere. It’s gravity wot done it.
No it’s not an eddy, it’s energy getting bled off as needed because the state change has more energy than an equal drop in temp without the state change.
That’s how they make voltage regulators, and switching supplies come in a pulse at a time, and there’s storage to bleed energy from to maintain the output voltage.
The atm has multiple independent agents operating. Tone doesn’t understand what that means apparently
I have a question for those who believe that CO2 warms (not merely slows cooling of) the atmosphere. Would you be saying the same things if CO2 increases warming by 10%, or if it increased warming by 0.000000001%?
Sky Dragons aside, i think the important point made by this thought experiment is that temperature is only one of several possible changes that could occur in the atmosphere in response to some new forcing.
Sure, if all the other variables stay constant, temperature should go up. But what if instead the volume or density or molar mass of the atmosphere adjusted slightly? When you’re talking about a fraction of a degree Kelvin increase over decades, that’s a pretty small fractional change.
Are we even looking for these tiny fractional changes in the total volume of the atmosphere, or total density, or total pressure?
If not, then we could easily be over estimating the temperature change in the model assumptions.
We may be progressing. Note that the sun provides the energy, no one claims otherwise. Atmospheres provide mass of a gaseous kind, obeying those Laws. Gravity acting on mass
causes pressure and lapse rates arise from gas physics.
@NikolovScience “Our P-T empirical relationship reveals the LONG-TERM steady-state controllers of climate. Solar irradiance & pressure determine the ENERGY ENVELOPE, within which other atmospheric processes operate such as IR radiative transfer & cloud dynamics.”
Didn’t someone in Australia patent a gigantic field of glass panels surrounding a chimney with the idea that the heated air under the glass would rush up the chimney and drive fans to generate electric power?
Looks like I was wrong about that. It was a US patent. They are referred to as solar updraft towers. More than one experimental tower has been built, and a commercial one is in the planning stages in Arizona.
https://www.digitaltrends.com/cool-tech/arizona-getting-colossal-solar-updraft-tower-in-2015/
Why are there questions here about whether gravitation compression creates energy or not? There is no argument that greenhouse gases create any amount of energy. The energy comes from outside the earth, from the sun. Both processes store energy from the sun for a short time, the exact time apparently being uncertain for GHGs.
I have seen green house effect calculations purporting to prove that delay is as short as two milliseconds between initial radiation from a solar heated surface and radiating out of the atmosphere versus contentions that the delay is, on average, some number of hours. Regardless, that energy must eventually be lost again, radiated away, but in the meantime the solar energy does many things here within the earth-atmosphere system. One of the things input solar does is provide heat that causes air to raise and expand, taking the temperature causing energy with it. This storage can be for some considerable time.
As the air raises it expands, cooling without losing energy. Jim Steele’s recent article here on last year’s Napa California grass fires explains how seasonal cooling in the Arizona high plateau brings colder, thus denser, air down the gravity well into California, heating it by as much as 50 degrees C as it compresses. This increases local temperatures greatly. This force feeds any fires that get started. Similar forced fires burned considerable acreage in Southern California a bit later in the year. When there are no fires, the local temperatures are simply many degrees warmer than they would be otherwise.
Input solar energy is obviously stored in many other ways. Plants use it to convert matter to a higher energy form, some of which can be retained for very long periods. Solar energy penetrates into water where some of it can be retained, apparently for centuries and longer.
There seems to be no controversy about these other activities. With adiabatic heating, no energy is created to heat the falling air and thus the country into which it flows; it is just energy from the sun that was stored in that air earlier in the season. Likewise, the arguments about GHG heating do not involve any new energy, just energy stored in molecular bonds. Arguments about adiabatic cooling/heating and whether any energy is created seem simply to be distractions, straw man arguments, that avoid any real questions.
“There is no argument that greenhouse gases create any amount of energy.”
Well, if you look at the Kiehl-Trenberth energy balance diagram, you will see 341 Wm-2 of incoming solar radiation at the TOA, but then we see 517 Wm-2 of energy striking the earth’s surface. If that is not energy creation, I don’t know what is.
I think you miss the whole idea of the paper, if the average temperature of all planets that we have these variables for, can be calculated with this formula to a very precise degree, without the need to look at the composition of the atmosphere, it says a hell of a lot about what can and cannot regulate natural variation. If c02 was a large driver, then the two planets closest to us, Venus and Mars, both mostly c02, should deviate quite a bit from these calculations, due to the so-called downwelling of c02. I am not so sure what is so hard to understand – he is not concluding the temp stays perfectly constant, he is concluding that if you can use these variables, which are not dependent on ‘greenhouse gases”, and predict the average heat of planets, then of course greenhouse gases are NOT the main drivers of a baseline temp. Like it our not we have an atmosphere due to gravity (and possibly our magnetic field helps maintain it). Venus is hot DUE TO SO MUCH MATERIAL IN THE ATMOSPHERE, not because it is mostly c02. Mars is frigid, but the percent of its atmosphere that is c02 is almost the same as venus, but its atmospheric pressure is very small compared to earth, and almost insignificant compared to venus. The idea that Venus at some point had a runaway greenhouse effect is backwards logic. Venus has high pressure because the density of its atmosphere, no matter the composition of that atmosphere. I am not discounting heat from the sun – but venus is covered in cloud and receives very little warning from the sun, and its six month long day is about the same temp as its 6 month long night. Why? Because atmospheric pressure dominates. YES the earths weather patterns are much more complex than either planet, but it will always seek equilibrium based on these very real gas laws.
Mr. Eschenbach knows how to “poke the bear.”
So you replace terms in the Ideal Gas Law with equivalent values and the lower atmosphere still seems to obey the IGL. Big Deal!
It’s like a magician during a card trick who forces someone to take the two of diamonds and then tells everyone it’s the two of diamonds. There’s nothing amazing here. The real surprise is when the magician thinks he’s actually done magic.
Jim
The author is right and Willis is wrong because the author states:
“Then adiabatic auto-compression provides the ‘other’ 33 Kelvin, to arrive at the known and measured average global temperature of 288 Kelvin. The ‘other’ 33 Kelvin cannot be provided by the greenhouse effect, because if it was, the molar mass version of the ideal gas law could not then work to accurately calculate planetary temperatures, as it clearly does here.”
Note that the author specifically excludes the “greenhouse effect”, i.e., CO2. Willis then disputes this with his “ten million nuclear reactors” example, but the author didn’t exclude that, he excluded only the CO2 greenhouse effect. So Willis’ rebuttal was off-topic. The author’s model of solar insolation + adiabatic gravity-induced compression is quite compelling if it indeed matches the surface temperatures across the Solar system.
The adiabatic heating prediction by Holmes is correct to the extent of the accuracy of the ideal gas law to model the states of atmospheric air. As noted by many commenters, an alternative equation of state could be selected to improve accuracy.
However, the use of an equation of state to calcuate a temperature of a given air volume at a known state (ground-level) is an improper use of the thermodynamic equations. Even if one accepts the dubious assumption of abiabatic heating, the use of an equation of state in the form of change in Pressure/Volume (expressed in the form of molar density as you please) results in a predition of change in temperature between State 1 and State 2 consistent with the assumptions embraced (adiabatic and constant mass in this instance).
In short, the proffered calculation is a prediction of what engineers call PV-work expressed as a temperature change from some (in this article) unstated reference condtiion wherein the PV work would be zero m³-kPa. What the number is not is a prediction of the actual temperature of the final state. Many who have enjoyed the North American winter will attest that ground-level air temperature can vary quite widely despite realtively small changes in barometric pressure.
The PV work equation could be as easily used with an adiabatic and isothermal (constant temperature) assumption which would predict exactly zero temperature change (well, duh) and a change in molar density. The equation is useful to calcuate a change of energetic condition between two given states; it is not useful to a priori calculate the temperature of a single, given state.
“Many who have enjoyed the North American winter will attest that ground-level air temperature can vary quite widely despite realtively small changes in barometric pressure.”
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Low pressure is what is making the South Pole so cold. It is not pressure change which is making the US so cold, this is caused by an increase in density. A 10% increase in density causes a 28C fall in temperatures.
[?? .mod]
“A 10% increase in density causes a 28C fall in temperatures.”
At constant volume. And pressure moves in the same direction as temperature only at constant density. If Robert would look at any weather station’s history over say a week, it will be obvious that at some times pressure and temperature are moving in opposite directions.
“At constant volume. And pressure moves in the same direction as temperature only at constant density. If Robert would look at any weather station’s history over say a week, it will be obvious that at some times pressure and temperature are moving in opposite directions.”
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Volume is not a parameter I use.
Sure, pressure and temperature can move in opposite directions; who said they couldn’t?
A glance at current Canadian temperatures show a higher pressure than average – but a lower temperature than average; again, this is due to a much higher density than average.
“At constant volume.”
Well, at constant pressure, which it pretty much is. The error is the assumption of causation. As said often elsewhere, you have two thermo variables to define a state, and the equation of state, here IGL, fixes the third. In this case, pressure is determined by mass of air, and temperature is determined by polar vortices etc. That then fixes the density, by IGL.
The contrary causation makes no sense. What would make the density change, if not temperature?
“Well, at constant pressure”
Yes, thanks Nick. P=density*R*T.
”Sure, pressure and temperature can move in opposite directions; who said they couldn’t?”
Robert Holmes said they couldn’t in the abstract:
“It is here demonstrated that the information contained in just these three gas parameters alone is an extremely accurate predictor of atmospheric temperatures”
Inspection of any weather station data shows there is no obvious relation between pressure and temperature in Earth atm. Sometimes temperature goes up and pressure goes down. Sometimes temperature goes down and pressure goes up. The IGL is not a good predictor of anything unless it can be supplemented by a constraint: Air density goes up as temperature goes down provided that pressure is constant.
Robert Holmes; ”Sure, pressure and temperature can move in opposite directions; who said they couldn’t?”
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Trick; “Robert Holmes said they couldn’t in the abstract”
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Robert Holmes (from the abstract); “It is here demonstrated that the information contained in just these three gas parameters alone is an extremely accurate predictor of atmospheric temperatures”
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I have no idea how you translated the latter sentence into me saying that pressure and temperature always go in the same direction!
It is obvious from the formula that this is only true if both the density and the molar mass do not change at the same time.
Let me clarify in a sentence or two for those of you who seem to be totally confusing themselves as Trick is.
Example; Earth’s global average near-surface air temperature.
The formula is as clear as day; it reveals that on short time-scales, air temperature is completely determined by a singular battle between air density and air pressure.
(Why the stipulation of ‘short time-scales’? Because on longer time-scales there will also be some input from molar weight, due to changing atmospheric constituents)
Robert, yes air temperature is completely determined by pressure and density (and M or Rspec). There is nothing surprising about it.
”I have no idea how you translated the latter sentence into me saying that pressure and temperature always go in the same direction!”
Because that is what you wrote: “these three gas parameters alone is an extremely accurate predictor of atmospheric temperatures”.
How many times have you been told cold air is denser than warm air? This is true only if qualified by other factors asserted being held constant like pressure. In weather station data by inspection there is no obvious relation between pressure and temperature as you assert. Other parameters are NOT held constant.
Any weather station data shows these three gas parameters alone are nowhere close to an extremely accurate predictor of atmospheric temperatures. If you think there is an obvious IGL relation, then actually pull down some data from any weather station of your choosing over a week. You will not be able to confirm your assertion from the data.
PS: Humorously, there are other factors affecting weather station temperature according to Anthony like the odd BBQ pit, tennis court, airport runway and jet exhaust!
And exactly what happens to the heat of evaporation trapped in the water vapor ( a GAS ) as it rises in this atmosphere and suddenly collides with a dust particle and turns back into water (Liquid). I see massive amounts of energy transported high into the atmosphere above thew so called CO2 “IR TRAP,” CAP, Insulator, whatever but never hear anyone talk about it. WHY?
usurbrain February 7, 2018 at 1:23 pm
The rising air normally cools according to the DALR (Dry Adiabatic Lapse Rate).
When condensation occurs within the rising air it is warmed by the released latent heat and thus cools more slowly, now according the MALR (Moist (or Wet) Adiabatic Lapse Rate).
This all assumes the air surrounding the rising (or sinking) air in is Hydrostatic Equilibrium and the process is adiabatic
This is basic meteorology, so perhaps talk to a meteorologist ;-).
usur, it is because they wilfully pursue a falsehood. Similar to claiming drugs expand conciousness, often same people. Curious, that.
Earthflux 20%plus by windows; convective: WV 80%, other gases radiating 20% approx..
Does it clarify to note that the ideal gas law applies to a closed system? Geoff.
Willis wrote: “In fact, it would be a huge shock if planetary atmospheres did NOT generally obey the Ideal Gas Law. After all, they’re gases, and it’s not just a good idea. It’s a Law ”
Unfortunately, it is difficult to apply the Ideal Gas Law to the atmosphere, because it doesn’t have a fixed volume. Temperature is not a function of pressure because volume is allowed to change.
The atmosphere isn’t a sealed system with a fixed volume, it is like a cylinder with a movable piston. The force hold the piston in place is the weight of the gas lying above the piston. That weight diminishes with altitude.
Those who believe that the 33 K GHE is due to pressure usually start by assuming that the atmosphere has a fixed volume and go wrong from there,
Frank: “Those who believe that the 33 K GHE is due to pressure usually start by assuming that the atmosphere has a fixed volume and go wrong from there.”
No, that’s not what’s assumed. What’s assumed is that 19,000 pounds per square foot, roughly, of atmospheric pressure at earth’s surface must impact the atmosphere’s capacity to hold heat, and as the pressure decreases with altitude, that must also affect the atmosphere’s capacity to hold heat.
Those who assume that it’s all about radiative physics are, in my opinion, stuck on the paradigm that says radiative physics takes top billing. Others of us think that the paradigm that says that pressure plays a important– even dominant– role in atmospheric physics, makes sense. So far it seems to me that those who want to defend the dominance of radiative physics are too intent on defending a paradigm that they’ve looked through for so long, rather than looking at the evidence.
Surface pressure is dominant simply because greater density increases the effectiveness of conduction.
The closer packed are the molecules at the surface the more energy they will draw from the irradiated surface and the higher the temperature can rise.
The declining density gradient with height marks the declining efficiency of conduction as density falls.
As density falls radiation increases relative to conduction until at top of atmosphere all is radiation to and from space.
The lapse rate slope describes the changing balance between conduction and radiation as one travels up along the decreasing density gradient.
SW: “The closer packed are the molecules at the surface the more energy they will draw from the irradiated surface and the higher the temperature can rise. The declining density gradient with height marks the declining efficiency of conduction as density falls.”
OK, good. So, to move the argument along and actually address specific issues, michael hammer says that without GHGs: https://wattsupwiththat.com/2018/02/06/ideal-gases/comment-page-1/#comment-2737619 “Once the air reaches the same temperature as the surface there is no net heat transfer from surface to air so we have a static atmosphere with no heat transfer in or our. No heating of the air near the surface so no increase in temperature driving convection. The lapse rate arises because of convection and cooling from above but if there is no cooling from above and no convection then the lapse rate does not need to occur. … Nitrogen and oxygen neither absorb nor emit thermal infrared energy to any significant extent.”
My question to MH would be, what would the temperature of GHG-free atmosphere be, then, if the earth is at 255K (for the sake of argument)? And to SW, what is your response to MH?
My reply to MH is that you cannot suppress convection for a sphere lit by a point source of light.
There will always be density differentials in the horizontal plane so the scenario he proposes is impossible.
Once convection begins there is a steady flow of energy from surface to air at the base of rising columns and an equal flow of energy from air to surface at the base of descending columns.
There will be a lapse rate reflecting the decline in density with height even without GHGs and there is no requirement for any energy to depart to space from the top of the atmosphere.
The cooling with height is instead created by the conversion of kinetic energy to potential energy as air moves upward along the lapse rate slope.
Don132: Thanks for the reply. I used to complain loudly about radiation getting top billing in the “climate show”. I hated the hype. Convection is extremely important to surface temperature. Speeding up the Hadley circulation can remove any extra heat at the surface produced by GHGs. Then I had a my personal “Eureka moment” and realized that radiation is the only thing that carries heat into and out of our planet. (We can quibble about and then neglect things like radioactive decay and the thousand years it takes for the deep ocean to impact surface temperature and heat from fossil fuel.) Aside from radiation, everything else merely moves heat around INSIDE our climate system – the atmosphere, a thin layer of land surface and the mixed layer of the ocean (the top 50 m on an annual time scale). When radiative cooling to space slows (by GHGs for example) or incoming radiation increases (more active sun or fewer clouds or aerosols), the climate system must warm SOMEWHERE. It doesn’t need to happen equally everywhere or at the surface.
So I eventually stepped back from prejudice against radiative forcing and recognized radiation’s predominant role. Perhaps you can too, but it was really difficult for me to abandon the justifiable skepticism that politicized climate science had produced in me.
Later I realized that the rate at which radiation leaves the upper atmosphere for space in the long run limits the rate at which heat leaves the surface by convection. If heat leaves from the surface any faster, the upper atmosphere warms, the lapse rate falls and convection shuts down. For example, if the rate of evaporation follows the C-C equation, the flux of latent heat increases 7%/K or 5.6 W/m2/K. However, if radiative cooling to space from the upper atmosphere doesn’t increase at a rate of 5.6 W/m2/K (K rise in Ts), then the lapse rate will become more stable, convection will slow, and humidity near the surface will increase. The planet’s climate feedback parameter (-3.2 W/m2/K for just Planck feedback) is the rate at which radiative cooling to space (and reflection of SWR) changes with Ts. On a planet without feedbacks, evaporation/precipitation couldn’t increase with warming at 7%/K = 5.6 W/m2/K, because a gray body at 288 K with emissivity 0.61 won’t permit it. Fortunately, the earth isn’t a simple gray body. Climate sensitivity (K/(W/m2)) is the reciprocal of the climate feedback parameter (W/m2/K)
Anytime one attempts to connect the temperature and pressure of our atmosphere using the ideal gas law confront an unsolvable problem: the volume isn’t fixed.
Don132 wrote: “What’s assumed is that 19,000 pounds per square foot, roughly, of atmospheric pressure at earth’s surface must impact the atmosphere’s capacity to hold heat.”
“Heat capacity” originates with conservation of energy. If more energy enters an object that leaves, then conservation of energy demands that the difference becomes “internal energy” (translation, rotation and vibration of molecules) aka higher temperature. Heat capacity is the factor that converts excess an energy imbalance (J) into a rise in temperature (K). If one pushes a piston on an isolated cylinder of gas the PdV work done on the gas will raise the temperature of the gas. However, if you wait long enough, the imperfect insulation on any isolated cylinder will allow heat to escape and the temperature return to the temperature of the cylinder’s surroundings.
For pressure to change the temperature of a gas, PdV work must be done. Pressure (Force/Area) alone doesn’t do any work or change internal energy. Work (energy) is force*distance. For a gas, that is Force/Area times distance*Area (volume). The distance (dx) a piston moves becomes a change in volume (dV). When a parcel of air in the atmosphere descends, it contracts under higher pressure (and warms). However, elsewhere in the atmosphere another parcel of air must be rising and cooling, and no NET work is done. To some extent, the atmosphere is like a scuba diver in the ocean with a weight belt to produce neutral buoyancy: No work is done moving upward vertically, because an equal weight of water moves down as you move up. And the vast pressure at the bottom of the ocean doesn’t make it warmer.
I took a long journey through climate science. Good luck with yours.
Frank,
Net work was done during the formation of the atmosphere and during the first convective overturning cycle. The thermal consequence of that net work remains until the atmosphere falls to the ground again.
It is no use trying to dismiss the thermal effect of conduction and convection by simply saying that all SUBSEQUENT convective cycles net out to zero.
Frank
“Unfortunately, it is difficult to apply the Ideal Gas Law to the atmosphere, because it doesn’t have a fixed volume. Temperature is not a function of pressure because volume is allowed to change.”
.
In my formula, which I call the molar mass version of the ideal gas law, I got rid of the volume so it’s not a problem. This formula works perfectly in the atmospheres of any planet with an atmosphere.
Temperature is completely decided by three gas parameters; pressure, density and molar mass.
”Temperature is completely decided by three gas parameters; pressure, density and molar mass.”
Actually only 2 parameters, pressure and density. One only needs to measure avg. pressure(z), avg. density(z) to get the avg. temperature(z) to instrument accuracy.
For Venus, NASA measured the atm. density(z) and already knew pressure(z). Once NASA had measured the atm. density(z), researchers really did use IGL to get Venus’ atm. temperature(z) curve. However they were only able to measure density(z) down to a certain altitude and extrapolated in troposphere to get their resultant atm. temperature(0) at Venus’ surface.
Trick
“Actually only 2 parameters, pressure and density. One only needs to measure avg. pressure(z), avg. density(z) to get the avg. temperature(z) to instrument accuracy. ”
.
On Earth we need molar mass as well. This is because of water vapour, which because of its much lower molecular mass than the atmospheric average must be taken into account. A 1% fall in molar mass reduces temperature by 2.8C.
“A 1% fall in molar mass reduces temperature by 2.8C.”
You have strange ideas on cause. Strictly, the IGL is an equation of state for a material, and if you change the composition, you have a different equation of state, even if it is just a different M. But that aside, it is always the case that if there is a change, the degrees of freedom, 3 in this case, will adjust somehow to accommodate. The IGL just defines one constraint. It doesn’t say that there will be a change in temperature.
If some water evaporates, the temperature may change if there is heat taken from the air in evap. The surface pressure can’t change much, else pressure gradient and acceleration. So the main response will be a change in density. That in turn will lead to convective instability, but that is not a matter for the IGL.
Of course it is !!!
The IGL describes the real world response to density variations.
Robert, congratulations on your paper. It is a clear and concise explanation of the Gravito-thermal theory and furthermore, it works!
Don’t pay too much attention to the criticisms here. Everyone has a theory.
George, that appears to be the case; everyone has a theory – even my taxi driver today!
“A 1% fall in molar mass reduces temperature by 2.8C.”
With other parameters held constant. The other parameters are not constant in earth atm. as any weather station’s data will show on daily, weekly (etc.) time frames.
Robert wrote: “In my formula, which I call the molar mass version of the ideal gas law, I got rid of the volume so it’s not a problem.”
I beg to disagree. In your derivation (copied below), temperature is a function of both pressure (P) and density (ρ). The mass and number of moles of gas is a conserved quantity, but their density changes with the volume they occupy. As I said, above:
“Those who believe that the 33 K GHE is due to pressure usually start by assuming that the atmosphere has a fixed volume and go wrong from there.”
P V = n R T (1)
Convert to molar mass;
P V = m/M R T (2)
Convert to density;
PM / RT = m / V = ρ (3)
Drop the volume, find for density;
ρ = P / (R T / M) (4)
Find for temperature;
T = P / (R ρ/M) (5)
ρ = near-surface atmospheric density in kg/m³
M = near-surface atmospheric mean molar mass gm/mol⁻¹
Frank, a common misconception, putting the cart before the horse.
Frank, indeed, IGL is tainted by containers. Not so in the unconfined atmosphere, nor is it when using the mylar balloon of the Berthold Klein experiment. Which warmista fear so much they cannot say its name…..
Brett wrote: “indeed, IGL is tainted by containers.”
You might look at this from a different perspective: A cylinder of gas with a piston that can move or not move. The IGL applies to both. The cylinder contains a fixed number of molecules. If the piston is locked in place, then volume and density are fixed. If not, they can change, like an atmosphere.
The other variable is whether or not the cylinder is so well insulated that the gas stays hot when compressed or is gradually returns to the temperature of its surroundings. We call the former “adiabatic”. Any atmosphere that contains GHGs emits and absorbs thermal infrared. But the rate at which the temperature is changed by thermal infrared can be slow enough that the expansion and contraction of air associated with vertical convection is essentially adiabatic.
However, despite what Steve Wilde says, the heat given off when the atmosphere formed (potential energy converted to kinetic energy as gas fell onto the surface 4.5 billion years ago) has long since been radiated to space.
That heat is constantly replenished by ongoing convective turnover. It is still present and will be present until the atmosphere falls to the ground.
Volume changes but mass does not so the pressure is the same at the surface regardless of volume.
Therefore the IGL works perfectly in the atmosphere even though it is comprised of non ideal gases. The variation caused by the non ideal nature of real world gases is too small to matter for all practical purposes.
Since pressure at the surface remains the same on average even if the atmosphere expands and since pressure determines density any increase in volume is self limiting in thermal consequences because expansion leads to less density at the surface so that conduction declines, the gases cool and the atmosphere shrinks back again.
So, temperature is not a consequence of pressure per se but rather a consequence of mass and gravity at any given level of irradiation and those three elements work as described by the IGL with variable pressure from place to place leading to consequent local or regional variations in the efficiency of conduction being merely a by product of that interaction.
“Therefore the IGL works perfectly in the atmosphere even though it is comprised of non ideal gases.”
Another unfounded assertion without actually looking at, and confirming from, weather station data. A better point would be departure from gas ideality doesn’t cause any known terrestrIal atmosphere phenomenon.
WIlde wrote: “So, temperature is not a consequence of pressure per se but rather a consequence of mass and gravity at any given level of irradiation and those three elements work as described by the IGL with variable pressure from place to place leading to consequent local or regional variations in the efficiency of conduction being merely a by product of that interaction.”
Now move the Earth to an orbit of 10 AU where incoming SWR is 1/100 the current value. Keep the same clouds for simplicity or let them change. Surface pressure is UNCHANGED because the same mass of atmosphere lies above. The volume shrinks (and the density increases) as the temperature falls. Or do you think that the temperature of our planet at 10 AU will be the same as 1 AU? How can the temperature remain the same if we radiate 240 W/m2 from the TOA at today’s temperature, but will receive only 2.4 W/m2. Use your common sense.
Since insolation is one of the three variable parameters (the others being mass and gravity) you have to adjust for distance from the sun so the temperatures will not be the same.
Frank, Stephen asserting: “temperature is not a consequence of pressure per se but rather a consequence of mass and gravity at any given level of irradiation” is just in his imagination. His past defense has been that he found this idea in a text in the 1960s but can’t cite the text, nor find it.
I’ve challenged Stephen many times if what he writes is true then he ought to be able to calculate earth global mean surface temperature from just mass, insolation and gravity for which I’ve given him the data. That stumps him so far, he can’t do so. Because his thesis is wrong.
A modern beginning meteorology text easily computes earth global mean surface temperature 288K from radiative 1LOT energy balance from measured input data (insolation, albedo, atm. emissivity, sigma). Stephen is not a student of atm. radiation as it is difficult involving calculus which is beyond even Stephen’s robust imagination.
Trick wrote: “A modern beginning meteorology text easily computes earth global mean surface temperature 288K from radiative 1LOT energy balance from measured input data (insolation, albedo, atm. emissivity, sigma). Stephen is not a student of atm. radiation as it is difficult involving calculus which is beyond even Stephen’s robust imagination.”
I understand where insolation, albedo, and sigma come from, but temperature depends on emissivity and emissivity is usually calculated from temperature. However, emissivity can be calculated by using the Schwarzschild eqn to calculate the change in outward flux as radiation passes through our atmosphere.
Steve Wilde gets fixated on certain thought patterns that have fundamental flaws he refused to recognize or forgets. We all tend to have this problem and need to listen to those who make sense or recognize contradictions we can’t resolve. I’m mostly writing for the benefit of others who might be confused by Steve or who are open minded enough to want to hear alternative positions. That isn’t always very productive.
Frank 9:26pm:
…brightness temperature depends on emissivity
….emissivity is usually calculated from thermometer temperature
@ur momisugly Frank February 10, 2018 at 9:26 pm
and @ur momisugly Willis
What strikes me is that those who hold the gravitational position aren’t stepping up to the plate and helping me as I stumble along. I’ve even provided helpful pathways to reason this through, such as suggesting that even though argon doesn’t radiate IR, it does radiate in other spectra, and as such it’s possible for it to lose energy as it moves away from the surface (irrespective of what pressure is doing) and if this is so then the atoms would lose velocity and the gas cool. Not getting much help on that one!
So I have to conclude that Willis is right regarding the isothermal GHG-free atmosphere because I see no other way out. Stephen says that any perturbations in the surface will set up convective turning; I don’t buy it, and even so, so what? The atoms are all isothermal (ultimately) and they can participate in convection all they want, they’re only moving from a region of one temperature to another region of the same temperature. If that heat can’t be convected away or radiated away or conducted away at the TOA, then it can only radiate away from the surface. Do the argon atoms emit in other frequencies and thereby lose velocity and thereby lose heat? No one seems to think so.
So T =pM/Rd in a GHG-free atmosphere doesn’t seem to say anything about how that atmosphere loses heat.
Willis has been patient overall; a big thanks for that! I really wasn’t trying to prove you wrong in the first place even though yes, I was quite sure you were wrong. I was trying to figure it out.
Don,
You are missing that Ke becomes Pe during ascent and Pe becomes Ke in descent.
That is why convective overturning matters.
All the molecules in an atmosphere have the same total energy (Ke + Pe) but Pe which does not register as heat increases with height and Ke declines with height so for a convecting atmosphere there must be a temperature decline with height even in a non radiative atmosphere.
The radiative proponents must address two critical issues:
i) How to get an isothermal, static atmosphere with no convection when it is impossible to arrange perfectly even surface heating. Even the slightest unevenness will allow less dense molecules to rise above more dense molecules. A declining density gradient ensures that once convection starts it will involve the full height of a non radiative atmosphere because a rising parcel of air only expands as fast as the density of the surroundings declines so that the density differential continues all the way to the top.
ii) How to avoid losing the atmosphere when the upward pressure gradient force in the top half of an isothermal atmosphere will exceed the downward pressure from the weight of the less dense molecules above. In that situation hydrostatic equilibrium cannot be achieved.
Until those issues are properly addressed the radiative hypothesis as applied to a non GHG atmosphere is simply a waste of all our time. All the thermal characteristics of a non GHG atmosphere are non radiative and so the radiative hypothesis cannot apply.
“Do the argon atoms emit in other frequencies and thereby lose velocity and thereby lose heat?”
Yes, Ar gas emits/absorbs at all frequencies, all temperatures, all the time as the bulk of the emission testing shows.
“No one seems to think so.”
Prof. Planck did. After his work was published around 1900-1914, Ar and other noble gas emission became a research topic in the 1920s and 1930s as the paper you linked demonstrates several papers in the ref.s. You found one paper testing for Ar emission in the 1.2-1.7 micron bandwidth (just see the title). Many other specialist authors published experimental noble gas data covering other bandwidths. Reading/citing the bulk of this work gets you to the top triangle of Willis’ pyramid.
Trick February 11, 2018 at 6:45 am: “Yes, Ar gas emits/absorbs at all frequencies, all temperatures, all the time as the bulk of the emission testing shows.”
But the issue is would it net absorb at the surface (because of the relatively high energy there) and net emit at TOA. If so, then at TOA argon would lose energy, atoms would slow down, gas would cool. I have no idea so I’m asking; I’m not stating.
“But the issue is would it net absorb…”
Net of what?
Don132 February 11, 2018 at 3:41 am
@ur momisugly Frank February 10, 2018 at 9:26 pm
and @ur momisugly Willis
What strikes me is that those who hold the gravitational position aren’t stepping up to the plate and helping me as I stumble along. I’ve even provided helpful pathways to reason this through, such as suggesting that even though argon doesn’t radiate IR, it does radiate in other spectra, and as such it’s possible for it to lose energy as it moves away from the surface (irrespective of what pressure is doing) and if this is so then the atoms would lose velocity and the gas cool. Not getting much help on that one!
Argon can only radiate in any part of the spectrum if it’s in an excited electronic state, that requires it to have been excited by EUV below ~108microns. In a pure Ar atmosphere the upper layer would absorb the small amount of the EUV like the thermosphere, however below that there would be no excitation so a GHG free troposphere.
To help Don, rising air doesn’t lose any energy as it cools. It converts heat in the form of KE to PE which is not heat and the process is fully reversible in descent. Total energy KE + PE stays the same for all atmospheric molecules once the atmosphere achieves hydrostatic equilibrium.
Don132, Trick, and others: Don wrote: “So I have to conclude that Willis is right regarding the isothermal GHG-free atmosphere because I see no other way out.”
Asking whether a GHG-free atmosphere will be isothermal isn’t a very profitable question. The answer may depend on how you believe a planet with such an atmosphere will behave. If the polar regions receive less sunlight than the equatorial regions, then convection is going to move heat from hot to cold and turbulently mix the atmosphere. If you imagine a planet in interstellar space with a surface evenly heated by radioactive isotopes in the ground, you get a different answer. To complicate things, quantum mechanic says that all transitions are possible, but some are extremely rare. If I understand correctly, Ar, N2 and O2 can emit thermal infrared, but their emission is negligible compared to CO2, CH4, N2O, and even man-made CFCs. But even a pure Argon atmosphere would have some emission and absorption. So I try to avoid answering questions about atmospheres with no GHGs.
I also avoid answering the question of the Earth’s temperature without GHGs. That depends on how albedo changes. The moon doesn’t have any GHGs and its surface temperature hard to calculate correctly (it varies with latitude) and requires assumptions about the effective heat capacity of the surface. It rotates once a month, and so is very hot during the “day” and cold at “night”. For me, the GHE is 150 W/m2, the difference between average surface emission and average TOA emission.
The best answer I have heard: If an isolated column of gas (or liquid) in a gravitation field spontaneously developed a temperature gradient, a heat engine or thermocouples could be used to extract work from that gradient. That would create a perpetual motion machine. Feynman makes this argument in Volume 1 of his lectures. Isothermal is what you expect from thermal diffusion (molecular collisions).
Nothing in nature is perfectly uniform so even that planet floating in space would have convection.
Since you cannot have an isothermal atmosphere with convection it is critical to the surface temperature enhancement to consider whether or not a non radiative atmosphere could become isothermal with no convection.
If it cannot then the gravito thermal effect is correct and the radiative effect is wrong.
Quite simply one cannot prevent convection on a sphere lit by a point source of light because surface heating is bound to be uneven and that is all you need for convection.
Thus Willis’s ‘proof’ is dead in the water.
Frank February 7, 2018 at 3:13 pm
Unfortunately, it is difficult to apply the Ideal Gas Law to the atmosphere, because it doesn’t have a fixed volume.
Holmes has removed volume from the equation and applies the gas law at the surface only
Roger: See my reply to Holmes. The change in volume become a change in density. Think a little.
Frank February 7, 2018 at 3:13 pm
The IGL does not apply to the atmosphere as a whole.
It should be valid however for limited volumes, where the local pressure and temperature should result in a certain density.
Ben Wouters wrote: “The IGL does not apply to the atmosphere as a whole. It should be valid however for limited volumes, where the local pressure and temperature should result in a certain density.”
You are correct, the Ideal gas law applies locally. However, a parcel of gas at a given altitude (which determines the local pressure can have ANY TEMPERATURE, because that parcel can occupy ANY VOLUME. Temperature is proportional to the mean kinetic energy and determined by how much energy (radiation) enters and leaves the parcel. IF more energy enters than leaves, the temperature will rise and the volume will increase. Some of the excess incoming energy will be consumed by the PdV work that is done when the gas expands.
PV = nRT
n/V = P/RT
The local pressure is determined by altitude. The local temperature depends on incoming and outgoing radiation. The local density varies with the local temperature. This is how the IGL is applied to systems where the volume can change. Only in closed systems with a fixed volume is pressure a function of only temperature or temperature only a function of pressure.
The stratosphere at 20 mb is warmer than the troposphere at 200 mb due to absorption of UV. The volume occupied by a mole of gas at 20 mb is more than 10X bigger than a 200 mb. If the temperatures were 250 and 200 K respectively, the volume occupied by one mole would be 12.5 X larger.
Frank February 10, 2018 at 1:39 pm
Perhaps ANY temperature is stretching it a bit, but this is imo correct.
To determine density we have to consider a given volume, irrelevant whether we use cm^3, dm^3 or m^3, as long as we use the same volume when comparing different parcels.
So, we can use equations derived for ideal black bodies on bodies that are NOT ideal black bodies, and we can use equations derived for ideal gases on gases that are NOT ideal gases.
I sense problems in the details of both. There’s got to be a better way.
I’m still having issues with something as basic as thinking we can correctly compare planetary effective temperature and average near-surface air temperature. … or choosing 6000K as the effective temperature of the sun, and where this layer of effective temperature supposedly is in the gradient of temperatures of the sun, and comparing this with where the layer of effective temperature of Earth is supposedly located with respect to its other layers, and how the layers of sun and earth effective temperatures can be considered to represent equivalent concepts and called the same layers of the same ideal, non-ideal black bodies.
There appears to be lots of room for confusion and/or sculpting of arguments to give priority to any number of insights.
I asked Stephen Wilde to point out the flaws in two separate proofs that gravity cannot warm a planetary surface on an ongoing basis. The proofs are here and here.
In response Stephen said:
Stephen Wilde February 7, 2018 at 1:59 pm
Several things.
First, Stephen, you told us “in another thread”? WHAT THREAD WHERE? In a galaxy far, far away … I am so tired of your endless unsubstantiated claims. You don’t seem to get it. Your handwaving goes nowhere with me.
Next, my proof doesn’t involve columns with vertical sides. My proof says nothing about columns, whether vertical or not. In fact, the word “column” doesn’t appear even once anywhere in my proof.
Which of course means you are attacking a straw man based on your imperfect memory … which is why I insist on people quoting what they are objecting to.
Next, you seem unclear regarding the process for refutation of a claim or a proof. Let me see if I can explain it. Over at “Digging in the Clay” Verity Jones has an excellent graphic showing the hierarchy of disagreement. The graphic deserves wider circulation. The types of disagreement range in a spectrum from the strongest, refuting the author’s central point, all the way down to the weakest, name-calling. Here’s the graphic:
The graphic is based on How to Disagree by Paul Graham, which is well worth reading.
One thing I’d like to highlight is that in the linked article the author says (emphasis mine):
Now Stephen, you have not even begun the process of refuting either proof. To my knowledge, no one has ever refuted either proof. To do so, as Graham says, you have to quote what you think is wrong — “You have to find a “smoking gun,” a passage in whatever you disagree with that you feel is mistaken, and then explain why it’s mistaken.”
I’d put your most recent comment at the level of “Contradiction — States the opposing case with little or no supporting evidence”.
How would you rate your comment?
Regards,
w.
PS—Note how I linked to your “most recent comment” above? That way people will know exactly what I am referring to, and there won’t be confusion or misunderstanding … please do us all the same courtesy.
Willis stated;
“I’m sorry, but the author has not demonstrated what he claims.
All that Robert Holmes has shown is that the atmospheres of planet obey, to a good approximation, the Ideal Gas Law.”
.
Willis is wrong. I could do no better than to quote a simple thought experiment, written by “The Reverend Badger” I present it here;
“Consider 2 rocky planets with thick atmospheres orbiting at the same distance from, just for fun, our very own sun. And let’s be really silly and have them in earth orbit as well. And even more ridiculously one has an atmosphere identical to the earth. Let this planet be E1.
Spec: E1 in earth orbit, same atmosphere as earth.
Now the other planet is E2 (how did you guess!). surprise surprise this is going to be identical to E1 EXCEPT for the composition of the atmosphere. The atmosphere of E2 will contain NO GHGs. It will be a nice mixture of various gases with exactly the same pressure, density and molar mass as E1. Just NO GHGs.
Clearly the existing greenhouse gas theory for Earth predicts that E1 should have a much higher (33K?) surface temperature than E2 Because of it’s GHGs.
The alternative theory/hypothesis of Robert predicts they will have identical temperatures. But interestingly the figure is the same as the other theory! Coincidence? Maybe.
How would you eliminate the possibility that a simple formulae with no reference to the percentage of GHGs in an atmosphere accurately predicts the temperature of a planet with a very specific (todays) percentage of GHGs. Well, have a look at other planets, some with huge GHG percentage (Venus). Obviously, a simple formula with no reference to GHGs would not be expected to fit 8 planets.
And yet it does.
The ONLY way that is possible IF the GHG theory is correct is that changes in GHG percentage in an atmosphere must alter the pressure/density/molar mass to make Robert’s formulae fit. But you could change the pressure/density/molar mass in EXACTLY the same way numerically using non GHGs to get the same result.
Therefore the GHG theory MUST be incorrect.”
My input;
The Molar Mass Version of the Ideal Gas Law says that since these two planets have the same density, pressure and molar mass, they MUST have the same temperature. Yet one of them contains GHG and the other does not.
In this way it is seen that either the Molar Mass Version of the Ideal Gas Law is correct or the (33C or whatever is claimed) greenhouse effect is correct – both cannot possibly be correct.
”In this way it is seen that either the Molar Mass Version of the Ideal Gas Law is correct or the (33C or whatever is claimed) greenhouse effect is correct – both cannot possibly be correct.”
Both IGL and GHG effect are correct, tested science Robert. To explicitly refute the central point (Willis’ pyramid top) of The Reverend Badger: you can’t get identical Earth’s at the same avg. density(0) as in the thought experiment you clip, one with natural GHGs and one without.
The problem I find in your paper is that NASA measured density(z) for Venus and, with p(z), used IGL to calculate temperature(z) which is the forward process. You can’t now use that knowledge of Venus temperature(z) to reverse engineer the IGL and claim anything new. Your paper simply rewrites the Venus research papers in reverse. I find nothing new in your paper.
Same deal for the other NASA measured planets. Ask if you need a ref. for the original NASA paper(s). They are easy to find for yourself.
Trick
If you quote someone, then quote them in context, otherwise you may be accused of putting up a straw man.
.
“Both IGL and GHG effect are correct, tested science Robert. ”
.
You claim here that the GHG effect is ‘correct and tested science’. I assume that in part, you refer to the GHG CO2. If this science is so correct and tested, then why isn’t there a published paper which quantifies / measures the supposed warming from ‘extra’ CO2 in our troposphere?
Trick.. Your comment is interesting:
“The problem I find in your paper is that NASA measured density(z) for Venus and, with p(z), used IGL to calculate temperature(z) which is the forward process.”
Can you confirm that the Venus probe did not measure both temperature and pressure on its decent to the surface? Can you confirm that the composition of the atmosphere was not known is some way through measurement?
The ideal gas law is p*V = n*R*T. R is a constant. I can pick any variable as the dependent variable and the other three can be anything (as long as I keep the gas relatively ideal). If I pick pressure then pressure is function of the other three values, p(n,T,V). If I pick volume then V(n,T,p). If I pick temperature then T(n,p,V). If I pick number of moles then n(p,V,T).
If I read Willis correctly, your equation is simply p*M = ρ*R*T. You’ve replaced V with M and n with ρ. Essentially I can still do the same with your equation. If I pick pressure, then p(T,M,ρ). If I pick molar mass, then M(T,p,ρ). If I pick density, then ρ(T,M,P). And finally, if I pick temperature, then T(p,M,ρ).
What you and “The Reverend Badger” don’t seem to understand, is that the values of M and ρ will adjust to the new temperature and pressure of planet E2 or any other planet.
Jim
sailboarder, NASA measured Venus atm density(z) by radio signal occultation experiments as their probe transmitted through Venus atm. The density modulated the carrier wave signal a measurable amount in a way that allowed atm. density(z) to be determined. I’d recommend pulling the original Venus papers for exact answers on how that works & what and how they knew of p(z), R. Very interesting application of IGL.
Essentially same process used for other planets & moons with atm.
Trick.. thanks. The Russians had their probe in the upper, earth like, region:
“The VEGA balloons were 3.5 – meter diameter super -pressure helium balloons. (An engineering model of the balloon is shown in figure 2) A 7 – kg instrumented payload package (figure 2, inset) was carried at the end of a 13 -meter tether. The payload was powered by primary batteries, with instruments to measure temperature, pressure, wind speed, light intensity, and aerosol density, as well as a low – power radio transmitter and system control
electronics”
So what you are saying is that from that altitude the IGLs are used to calculate the surface conditions. Is that not empirical ? How can one then assert circular reasoning? I could post the atmospheric composition in the Venus paper I read, but that is not necessary with the direct measurement of density. The circular reasoning assertion is in my opinion not correct.
”Is that not empirical ?”
NASA’s T(0) for Venus is indeed empirical using the experimentally verified theory of the IGL from their measured density(z) and obtaining p(z).
”How can one then assert circular reasoning?”
A search shows I didn’t assert the term circular. Btw the Russians also had the Venera series landers.
Robert 7:15pm: ”If you quote someone, then quote them in context, otherwise you may be accused of putting up a straw man.”
A straw man changes the proposition; my direct quote did not do so and the context is easily found in the directly above comment. Your practice of long quotes is laborious. I prefer the style of more focused quotes.
The papers you seek are too numerous to cite; I’d recommend anyone start by pulling the papers you mention in your article & then pulling their ref.s, and supplement with a basic atm. thermo. text as some of the paper terms and discussions are specialist in nature. I did so for a few you listed and found where the IGL parameters you mention were actually initially sourced to form a view nothing was new or novel in your paper.
Trick
“NASA’s T(0) for Venus is indeed empirical using the experimentally verified theory of the IGL from their measured density(z) and obtaining p(z).”
These NASA scientists thus ignored radiative effects and used PV=nRT? Does that mean they do not accept Hansen’s approach? That is totally a paradox. Do they fight internally I wonder, or do they just celebrate how many billions Hansen brings in to launch rockets and satellites?
Can’t be, can it?
sailboarder 6:09am: “These NASA scientists thus ignored radiative effects and used PV=nRT?”
No, researchers used IGL in form of P(z)=density(z)*R*T(z)
All the radiative, orbital, weather effects so forth are already naturally in the Venus atm. density(z) that NASA measured. IGL reduced to one eqn. one unknown: T(z). Pull the original papers, you can trace them back through the ref.s in the top post paper.
Trick
OK, that is a different form of the same equation, which I derived myself. The odd thing was that the units required a depth, to get the V. I used 1 meter, ie, the earths surface, and derived the 287K.
Again, imo the radiative effects are just one of the internal means for the troposphere to move heat around and cool the planet. Agree? Yes? No?
Willis..
Your first reference:
” The EEJ assertion, that the dry adiabatic lapse rate alone explains the bulk of so-called “greenhouse warming” of the atmosphere as a stable feature of a bulk equilibrium gas, is incorrect.”
Stable feature, no. There is constant churning in the atmosphere to disgorge the insolation.
Your second reference:
“They say that somehow a combination of gravity and a transparent, GHG-free atmosphere can conspire to push the temperature of a planet well above the theoretical S-B temperature, to a condition similar to that of the Earth.”
In your refutation, what insolation do you use for earth and your reference non GHG earth planet? Clearly, they are not the same, so the surface temperatures would be different. That’s not similar to start with.
sailboarder February 7, 2018 at 6:21 pm
sailboarder, I have no idea who said that or where. A bit of context would be useful.
Thanks,
w.
W
The text is in the conclusions section of your link reference 1, which you submitted to Steven above in your pyramid post.
sailboarder February 7, 2018 at 7:39 pm
Thanks for the clarification. That’s Robert Brown’s proof, not mine.
w.
Willis..
I admit o going down rabbit holes with debating the “greenhouse” effect of CO2. For example, was the IGL used along with the Russian probe to calculate the surface temperature of Venus? If so, they did what this author did. They clearly did not invoke radiative theory since the IGL does not include such a calculation. Call me mystified.
I think the important question is what is the surface delta T (sensitivity), associated with the higher levels of CO2. The author uses molar density changes to calculate a tiny number. So far I agree.
So what could be a test? How about using minimum night temperatures in the lowest humidity level areas of the world. The central Antarctic would be a candidate would it not? How about the Sahara desert in the driest part of the year? Clearly, if there is going to be a sensitivity due to CO2 it should show up there first, by progressively warmer nights.
Here’s the day too day change in both min and max temp for the SW US deserts
micro6500
Your day to day changes I assume are averages over each year. In any case, I cannot see a trend. That is suggestive of no heat trapping effect of higher CO2 levels. Agree?
Yes.
Correct
Agreed
Yes
😉
Trick – JPL vs GISS
I can’t quite put my finger on it, but there seems to be something off about the “proof” cited here: https://wattsupwiththat.com/2012/01/24/refutation-of-stable-thermal-equilibrium-lapse-rates/
Unfortunately, the link to the paper that this proof is trying to refute no longer leads to the paper being refuted, but I found it anyway in a Google search, skimmed it quickly, and noted that it was a very idealized thought-experiment set-up, where the picture of the model in my mind did not match the picture of the column of gas in the supposed “proof” against it.
I envisioned a spherical-shell diagram, but the supposed “proof” shows a rectangular representation of what I assume is a long cylinder with a thin tube (wire) connecting the bottom to the top, which seems like a different set up that has the system going outside itself, so it may route back inside itself to violate the adiabatic set up, which seems like a trick, rather than an explanation of a fault, hence, maybe even a straw man. It’s very confusing, and I think it looks more like an argument against how a thought experiment was set up, with possibly some confusion between the two authors on terminology.
I’ll try to wade through it all again with greater focus, but that’s gonna take some time. Maybe I will resolve my bad feeling about it, … or maybe not.
Refutation of Stable Thermal Equilibrium Lapse Rates by Robert G. Brown,
Duke University Physics Department, … in the WUWT article here: https://wattsupwiththat.com/2012/01/24/refutation-of-stable-thermal-equilibrium-lapse-rates/
… claimed to refute
The “Greenhouse Effect” As A Function Of Atmospheric Mass by Hans Jelbring, Energy & Environment, Vol. 14, Nos. 2 & 3, 2003, .. located here:
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjGg_yR8JbZAhVE21MKHRqIAW8QFggnMAA&url=http%3A%2F%2Fruby.fgcu.edu%2Fcourses%2Ftwimberley%2FEnviroPhilo%2FFunctionOfMass.pdf&usg=AOvVaw0DE5HBeN13t2TSft1AHGRg
Well, as I hinted earlier, I had a funky feeling [so scientific, I know] about this supposed proof, and given other comments that I have read elsewhere (from years back), I’m still not ready to dismiss the gravitational approach. See, for example, the comment here:
https://tallbloke.wordpress.com/2012/01/01/hans-jelbring-the-greenhouse-effect-as-a-function-of-atmospheric-mass/#comment-14237
The story seems so much more complex than “nails-in-the-coffin” posturing might first lead one to believe.
Needless to say, I am not ready to bury this approach yet.
Robert Kernodle February 7, 2018 at 9:22 pm
I can’t quite put my finger on it, but there seems to be something off about the “proof” cited here: https://wattsupwiththat.com/2012/01/24/refutation-of-stable-thermal-equilibrium-lapse-rates/
I agree. Consider this quote:
“If we assume a constant temperature in the adiabatically isolated container,…”
But the atmosphere temperature varies with height.
So the model used and thus the refutation are not valid.
Bob and Roger: You are correct: Brown is assuming what he wants to prove.
Consider a plane in an isolated cylinder of gas in the absence of gravitational field. If the cylinder is in EQUILIBRIUM, the same number of gas molecules must be traveling upward through the plane as downward through the plane. Now turn on the gravity and wait for equilibrium to be restored. The pressure and density of the gas just above the plane are slightly lower than below, but we don’t know if there is a temperature gradient across that plane. If there is no temperature gradient the average molecular speed will be the same above and below the plane. There will be more molecules traveling upward than downward. Those deriving thermo-gravity ignore this density difference. Between collisions, there the downward moving molecules crossing the plane will accelerate slightly from gravity and the upward moving molecules will decelerate slightly. That will compensate for the difference in density if the column is isothermal.
However the temperature gradient in our atmosphere isn’t determined by such molecular motions (even though they are a thought experiment with an isolated cylinder in a gravitational field. In the real atmosphere, heat is transferred vertically by four mechanisms: convection, radiation, molecular collisions, and finally gross molecular motion. The mechanism that transfers heat the fastest will be the one that controls the lapse rate. Convection produces a lapse rate of -g/Cp and bulk motion means molecules will not fractionate by molecule weight. Thermal equilibrium produced by radiation alone produces a curved lapse rate. With molecular collisions, the upward moving molecules have slightly less kinetic energy, but this difference in our gravitational field is many orders of magnitude less than the amount of kinetic energy that will be randomly exchanged by the collision. Finally, gross molecular motion converts kinetic energy / temperature into potential energy – producing thermogravity and a -g/Cp lapse rate with fractionation of molecules by molecular weight.
In the troposphere, we observed a lapse rate of -g/Cp AND no fractionation by molecular weight. Our lapse is therefore caused by convection.
Above about 100 km, the atmosphere becomes enriched with lighter gas molecule because of fractionation by molecular weight. This is because molecular collisions are rare at this altitude and molecules can interconvert a significant amount of kinetic and potential energy between collisions. This is where thermogravity could operate. However, temperature isn’t defined in a thermodynamic sense when molecule are not colliding frequently.
Frank February 9, 2018 at 1:18 pm
Most of what you write makes sense. Have to disagree with this though:
Convection does not produce a lapse rate. The -g/Cp (Dry Adiabatic Lapse Rate) only gives the temperature change of a (limited) volume of air rising (or sinking) within an atmosphere that is in Hydrostatic Equilibrium.
(and no condensation takes place, otherwise the MALR applies)
Since the process is assumed to be adiabatic there is no influence on the surrounding air.
Convection is mostly limited to the lower 1-2 kilometers of the atmosphere. Exceptions eg the large cumulonimbus clouds that may reach into the tropopauze. Often no convection is happening at all (eg during the night).
Average temperature profile for mid latitudes is ~6,5 K/km for the tropsphere. DALR is ~9,8K/km.
A lapse rate develops wherever there is convection of gases within a declining density gradient though there are inversion layers within the system especially at the tropopause.
There is convection in the stratosphere within the Brewer Dobson circulation and there will also be convection higher up but the air is so thin that we have never been able to observe it.
Gravity creates the density gradient in the first place.
Ben Wouters wrote: “Most of what you write makes sense. Have to disagree with this though: Convection produces a lapse rate of -g/Cp” Convection does not produce a lapse rate.
Thanks for the kind reply. You are correct that I made errors when oversimplifying .
Does convection produce a lapse rate? I think so. The atmosphere becomes unstable towards “buoyancy-driven” convection when the lapse rate exceeds a critical value. Above that value, a rising air parcel expands and cools, but is still less dense than the air above. So, the parcel continues to rise. When buoyancy-driven convection has transferred enough heat vertically (raising the temperature higher in the atmosphere), rising air expands and cools, but is now as dense as (or more dense than) the surrounding air. The air no longer rises spontaneously. The shut down of spontaneous buoyancy-driven vertical convection leaves a MALR – on the average. (The MALR is the DALR, -g/Cp, modified to account for the heat released by condensation.) Individual radiosonde soundings, however, are highly irregular due to the chaotic motion of air masses, and inversions produced at night. Unstable lapse rates (CAPE, Convective Available Potential Energy) are not instantly discharged.
The internal energy in temperature can be combined with the energy in PdV work to produce a concept called “potential temperature”. When latent heat is added, it becomes “moist potential temperature”. In the link below, you can see the regions of our atmosphere with the same moist potential temperature produced by buoyancy-driven vertical convection halting at the MALR. (These are annual average temperatures.) Where moist potential temperature increasing altitude, stable lapse rates (no convection) generally exist and radiative equilibrium is controlling the atmosphere’s temperature.
https://scienceofdoom.com/2012/02/12/potential-temperature/
The combination of these two processes is called radiative-convective equilibrium. Where radiative cooling fails to remove heat from the surface fast enough and an unstable lapse rate develops, convection supplements radiative cooling, leaving a MALR behind.
In most of the troposphere, we observed a MALR AND no fractionation by molecular weight. In these regions, the lapse rate is caused by convection. In others, it is the result of radiative equilibrium.
Fractionation by molecular weight occurs above 100 km, the “turbopause”. (See wikipedia.) Above there, turbulent mixing no longer carries heavier molecules as high as lighter ones. Thermo-gravity is derived from the princple that the sum of kinetic and potential energy is conserved. Clearly this concept doesn’t work in the troposphere, where heavier CO2 molecules have 52% more potential energy at any given altitude, but have the same temperature (which is proportional to kinetic energy).
Steve Wild wrote: A lapse rate develops wherever there is convection of gases within a declining density gradient though there are inversion layers within the system especially at the tropopause.
No, a lapse rate CAN BE produced by ANY PROCESS that transfers heat vertically in the atmosphere: convection, radiation, conduction (molecular collisions) and molecular diffusion. That lapse rate can be zero. Thermo-gravity is derived applying the principle of conservation of energy to molecular diffusion: The altitude/potential energy of gas molecules determines their kinetic energy and therefore their temperature. If not other processes resulted in vertical transfer of heat, thermo-gravity would determine our lapse rate. However, convection, radiation and even conduction of heat (by collisions) are all much faster than molecular diffusion.
The stratosphere is warmer than the upper troposphere because solar UV is absorbed there. Here the temperature is determined by radiative equilibrium, because it transfers energy the fastest. By acknowledging the reality of the tropopause, Steve Wilde is admitting that molecular diffusion transfers heat more slowly than radiation.
The molar ratios of gases in both the stratosphere and the troposphere don’t vary with molecular weight. The potential energy of gas molecules does vary with molecular weight. We therefore know that the principle of conservation of PE+KE doesn’t determine temperature in these regions – because energy is also being moved by latent heat, PdV work, and latent heat. Above the trubopause at 100 km, the atmosphere is enriched with lighter molecules
The potential energy (mgh) of an expanding gas in a cylinder with a piston doesn’t change, if the piston moves horizontally. According to the principles used to derive thermogravity, the temperature of the gas has no reason to change upon expansion. If the piston moved vertically, the temperature would change. Why Don’t adiabatic expansion problems specify whether the piston moves vertically? The PdV work many order of magnitude greater than the potential energy gain.
The change in potential energy of gas molecules between collisions is many orders of magnitude smaller than the average amount of kinetic energy transferred by a collision. Even in the absence of radiation and convection, an isolated column of gas will be isothermal when molecules are colliding frequently.
Frank February 10, 2018 at 12:37 pm
Not sure if we have the same ideas about convection.
Lets start with a static atmosphere with a 6,5K/km lapse rate all the way to the tropopauze.
Somehow a parcel (bubble) of air becomes heated at the surface, and leaves the surface when its temperature is 3,3K warmer than the surrounding air. This parcel will rise to 1 km where it has cooled 9,8K.
Static atmosphere is here 6,5K colder. So the rising stops here, unless condensation kicks in before the parcel reaches 1km. Somewhere near air from above will sink to the surface to replace the rising air.
I don’t see any heating of the the air at 1km due to convection.
Potential temperatures are calculated values, no real process involved.
The following links give a lot of info about how understand theses various processes:
https://www.atmos.illinois.edu/~snesbitt/ATMS505/stuff/09%20Convective%20forecasting.pdf
and
http://www.tornadochaser.net/capeclass.html
Best to keep it simple and exclude the wide variety of environmental processes that can interfere with the raw numbers.
A parcel gets warmed by uneven surface heating to a temperature 3.3k warmer than the surroundings.
If the parcel warmed by the surface rises It will cool at the dry rate of 6.5K/km and so at the tropopause it will still be 3.3k warmer than the surroundings.
At the tropopause it hits an inversion layer caused by direct UV heating of a layer of ozone molecules.
It is pushed to one side by warmer air continuing to come up from below and then starts to sink back to the surface.
It warms all the way back to the surface at the dry rate of 6.5km and returns to the surface at the ORIGINAL temperature.
What has happened is that the surface was cooled by 3.3K when uplift occurred and warmed by 3.3K after descent for a net zero thermal effect.
BUT during the formation of the atmosphere the process was NOT net zero during that formation . During the formation the surface was cooled below S-B during the ascent but the energy removed was then returned to the surface at the end of the first convective overturning cycle and then has to be ADDED to continuing insolation to give the surface thermal enhancement above S-B.
And that happens even with a completely non radiative atmosphere.
“Lets start with a static atmosphere with a 6,5K/km lapse rate all the way to the tropopauze.
Somehow a parcel (bubble) of air becomes heated at the surface, and leaves the surface when its temperature is 3,3K warmer than the surrounding air. This parcel will rise to 1 km where it has cooled 9,8K.
Static atmosphere is here 6,5K colder. ”
.
My question is; why would the parcel cool 9.8K when the surrounding air is cooling at only 6.5K.
The rise would be adiabatic and so why would the parcel cool more than the surrounding air?
Seems to me the parcel would retain the 3.3K of energy picked up at the surface until it reaches the tropopause.
”Somewhere near air from above will sink to the surface to replace the rising air.
I don’t see any heating of the the air at 1km due to convection.”
Ben 7:06am, the upper air does not sink to the surface as in Stephen Wilde’s imaginary descending column. Nature is much messier. If you go to youtube and search on convection, then find there are experiments showing what really does happen in convecting nature.
Rising columns are reasonably evident but not descending columns. Some of the same temperature surface fluid is pulled in from the sides at z=0 as the locally warmed fluid rises and the warmer fluid stays at height dispersing its higher than surroundings kinetic energy until it equilibrates. This is how you can see warming of the higher-level fluid due to convection.
Every high pressure cell contains air spiralling downwards and outwards. Such cells comprise half the atmosphere.
Ok, Stephen now instead of imaginary descending columns you imagine air “spiraling” downwards (and outwards). Please point this out actually occuring in nature in one of the youtube convection videos.
Basic meteorology. Air spirals up and inwards towards low pressure and down and outwards from high pressure. Read about isobar maps and you will find that air flows at an angle across lines of equal pressure from high to low.
Trick February 11, 2018 at 7:50 am
Wasn’t thinking about descending columns. A rising thermal is often surrounded by sinking air. Well known effect for (para)gliders.
I think the net effect of a rising thermal is a redistribution of the extra energy it accumulated at the surface, This energy does not show up as a higher temperature at the height where the thermal stops rising, since the thermal stops rising when its density (~temperature) is equal to that of the surrounding air.
”Basic meteorology.”
Basically Stephen’s imagination & straw man. The youtube videos demonstrate convection physics in a fluid warmed from below in a gravity field. The fluid acts as shown.
Geostrophic winds parallel to isobars is changing the proposition.
—-
Ben, the youtube convection videos to a very small extent support your contention that a rising thermal is often surrounded by sinking air. The fluid tends just to rise more slowly as it spreads out. After rising and warming the ambient fluid, the convecting fluid tends to spread laterally way more than sink. A test of this sort is about as high on Willlis’ pyramid as possible.
Ben wrote: “Lets start with a static atmosphere with a 6,5K/km lapse rate all the way to the tropopauze.
Somehow a parcel (bubble) of air becomes heated at the surface, and leaves the surface when its temperature is 3,3K warmer than the surrounding air. This parcel will rise to 1 km where it has cooled 9,8K.
Why did the parcel rise? Surface pressure is (roughly) the same everywhere. So warmer means less dense. Less dense means that as more dense (cooler) fill flow under the parcel as it rises. Thus my term “buoyancy-driven convection” (as opposed to air motion driven by wind, say up the slope of a mountain).
Why does it cool? At 1 km, the pressure will be about 0.9 atm. So the volume of the gas will expand 11%, doing PdV work. Assuming the expansion is adiabatic, the energy needed to perform that work will be taken from the internal energy of the gas. That produces a temperature change of -9.8 K for a rise of 1 km. Unless moisture in the air condenses and releases latent heat. Then the change can be as modest -4.9 K/km for the most humid regions on the planet. In practice, rising parcels of air follow the DALR until the lifting condensation level (LCL) and the SALR (saturated ALR) above. On the average, the lapse rate apparently is above 6.5 K/km because dry descending air chaotically mixes with moist ascending air, but real soundings are highly irregular.
Anyone citing links to skew T/log P plots probably understands some of this better than I do. (I haven’t studied any meteorology.) If you read the link about potential temperature, it simply is the temperature of a parcel at any altitude would have if it were subjected to surface pressure. Moist potential temperature is the temperature the parcel would have if it were subjected to surface pressure and the water vapor present at the surface below released its latent heat into the parcel.
In Ben’s earlier comment, he said: “Convection is mostly limited to the lower 1-2 kilometers of the atmosphere. Exceptions eg the large cumulonimbus clouds that may reach into the tropopauze. Often no convection is happening at all (eg during the night)”
I showed you the plot of moist potential energy to show you the regions of the atmosphere where convection, adiabatic expansion and latent heat determine the temperature. The same moist potential temperature is found as far vertically as convection is needed (and radiative cooling isn’t enough to remove all the heat provided by SWR). (Because these are annual average, the difference in convection between summer and winter is missing).
Hopefully, there are no areas of disagreement left.
Frank
“a 6,5K/km lapse rate all the way to the tropopauze…This parcel will rise to 1 km where it has cooled 9,8K. ”
.
Why would it cool 9.8K if the lapse rate is 6.5K? It would cool 6.5K.
.
“Why does it cool? At 1 km, the pressure will be about 0.9 atm. So the volume of the gas will expand 11%, doing PdV work. Assuming the expansion is adiabatic, the energy needed to perform that work will be taken from the internal energy of the gas. ”
.
Why would it be doing any work to expand as it rises? The entire atmosphere is less dense as the parcel moves upwards. It would only be doing work if it stayed at the same volume.
.
“Convection is mostly limited to the lower 1-2 kilometers of the atmosphere. ”
.
That is a new one. The height of convection depends on the latitude. From 45 deg N to 45 deg S the convection averages 15-17km. Above 45 deg latitude the convection averages 10km.
A sudden vertical displacement in the tropopause occurs where these regions meet.
Frolly: I admire you persistence in trying to get answers from a long thread like this one. Hope what follows helps:
Ben wrote: “a 6,5K/km lapse rate all the way to the tropopauze…This parcel will rise to 1 km where it has cooled 9,8K. ”
.
Frolly asks: Why would it cool 9.8K if the lapse rate is 6.5K? It would cool 6.5K.
Frank replies: Rising and falling air parcels don’t exchange heat via radiation very fast (or physically mix), so we calculate the temperature change associated with vertical convection as if the parcels were completely isolated from their surroundings. The technical term for this is “adiabatic”.
.
Frank replied to Ben: “Why does it cool? At 1 km, the pressure will be about 0.9 atm. So the volume of the gas will expand 11%, doing PdV work. Assuming the expansion is adiabatic, the energy needed to perform that work will be taken from the internal energy of the gas. ”
.
Frolly asks: “Why would it be doing any work to expand as it rises? The entire atmosphere is less dense as the parcel moves upwards. It would only be doing work if it stayed at the same volume.”
Work is force times distance change (dx). For a gas in a cylinder with a piston of area A, that is F/A times
A*dx which is P*dV where dV is the change in volume. Because the air rose, it expanded and did work and cooled. Somewhere else, air subsided and had work done on it and warmed. Stationary air remains at the same temperature (which on the average is 6.5 K/km colder at higher altitudes).
As the parcel of gas rises, the weight of the gas above decreases slightly, meaning the pressure on that parcel decreases slightly. If temperature remained the same, the volume would increase (dV), meaning that PdV work had been done against the pressure of the surrounding atmosphere. If nothing else supplied the energy for this work, the law of conservation of energy means it comes from the internal energy of the gas – meaning it cools. Since the temperature has dropped, the gas doesn’t expand as much as it would have if a heat source kept the gas at a constant temperature.
.
Ben wrote: “Convection is mostly limited to the lower 1-2 kilometers of the atmosphere. ”
.
Frolly commented: That is a new one. The height of convection depends on the latitude. From 45 deg N to 45 deg S the convection averages 15-17km. Above 45 deg latitude the convection averages 10km.
A sudden vertical displacement in the tropopause occurs where these regions meet.
Frank replies: Convection occurs because thermal infrared can’t transfer energy through our fairly IR-opaque atmosphere as fast as SWR delivers it. A lot of the opacity is due to water vapor and it drops of rapidly with temperature. When the lower atmosphere gets too warm, the atmosphere beomes unstable toward convection. Convection results in a linear lapse rate. Most climate scientists define the tropopause as the altitude where the lapse rate fall below 2 K/km (too low to be due to convection), but others say 0 K/km. In the tropics, there is a sharp change in lapse rate at about 17 km, but this change is more gradual and begins much lower in the extra-tropics, 9-13 km depending on the season, outside the tropics. However, at high latitudes, the lapse rates lower than 6.5 K/km can be due to radiative equilibrium, so the tropopause may not coincide with the upper limit of convection, as it does in the tropics. I would GUESS Ben’s value of 1-2 km for the upper limit of convection is too low, but opacity to thermal decreases rapidly once water vapor decreases rapidly in the first 1-2 km.
Willis,
As a precursor to your ‘proof’ you approved and thus adopted Robert’s flawed model so any criticism of that is equally a criticism of your ‘proof’. You always refer to both works together.
Unless you deal with the difference between Robert’s model and the real world your ‘proof’ is just meaningless waffle.