By Robert G. Brown, Duke University (elevated from a WUWT comment)
I spent what little of last night that I semi-slept in a learning-dream state chewing over Caballero’s book and radiative transfer, and came to two insights. First, the baseline black-body model (that leads to T_b = 255K) is physically terrible, as a baseline. It treats the planet in question as a nonrotating superconductor of heat with no heat capacity. The reason it is terrible is that it is absolutely incorrect to ascribe 33K as even an estimate for the “greenhouse warming” relative to this baseline, as it is a completely nonphysical baseline; the 33K relative to it is both meaningless and mixes both heating and cooling effects that have absolutely nothing to do with the greenhouse effect. More on that later.
I also understand the greenhouse effect itself much better. I may write this up in my own words, since I don’t like some of Caballero’s notation and think that the presentation can be simplified and made more illustrative. I’m also thinking of using it to make a “build-a-model” kit, sort of like the “build-a-bear” stores in the malls.
Start with a nonrotating superconducting sphere, zero albedo, unit emissivity, perfect blackbody radiation from each point on the sphere. What’s the mean temperature?
Now make the non-rotating sphere perfectly non-conducting, so that every part of the surface has to be in radiative balance. What’s the average temperature now? This is a better model for the moon than the former, surely, although still not good enough. Let’s improve it.
Now make the surface have some thermalized heat capacity — make it heat superconducting, but only in the vertical direction and presume a mass shell of some thickness that has some reasonable specific heat. This changes nothing from the previous result, until we make the sphere rotate. Oooo, yet another average (surface) temperature, this time the spherical average of a distribution that depends on latitude, with the highest temperatures dayside near the equator sometime after “noon” (lagged because now it takes time to raise the temperature of each block as the insolation exceeds blackbody loss, and time for it to cool as the blackbody loss exceeds radiation, and the surface is never at a constant temperature anywhere but at the poles (no axial tilt, of course). This is probably a very decent model for the moon, once one adds back in an albedo (effectively scaling down the fraction of the incoming power that has to be thermally balanced).
One can for each of these changes actually compute the exact parametric temperature distribution as a function of spherical angle and radius, and (by integrating) compute the change in e.g. the average temperature from the superconducting perfect black body assumption. Going from superconducting planet to local detailed balance but otherwise perfectly insulating planet (nonrotating) simply drops the nightside temperature for exactly 1/2 the sphere to your choice of 3K or (easier to idealize) 0K after a very long time. This is bounded from below, independent of solar irradiance or albedo (or for that matter, emissivity). The dayside temperature, on the other hand, has a polar distribution with a pole facing the sun, and varies nonlinearly with irradiance, albedo, and (if you choose to vary it) emissivity.
That pesky T^4 makes everything complicated! I hesitate to even try to assign the sign of the change in average temperature going from the first model to the second! Every time I think that I have a good heuristic argument for saying that it should be lower, a little voice tells me — T^4 — better do the damn integral because the temperature at the separator has to go smoothly to zero from the dayside and there’s a lot of low-irradiance (and hence low temperature) area out there where the sun is at five o’clock, even for zero albedo and unit emissivity! The only easy part is to obtain the spherical average we can just take the dayside average and divide by two…
I’m not even happy with the sign for the rotating sphere, as this depends on the interplay between the time required to heat the thermal ballast given the difference between insolation and outgoing radiation and the rate of rotation. Rotate at infinite speed and you are back at the superconducting sphere. Rotate at zero speed and you’re at the static nonconducting sphere. Rotate in between and — damn — now by varying only the magnitude of the thermal ballast (which determines the thermalization time) you can arrange for even a rapidly rotating sphere to behave like the static nonconducting sphere and a slowly rotating sphere to behave like a superconducting sphere (zero heat capacity and very large heat capacity, respectively). Worse, you’ve changed the geometry of the axial poles (presumed to lie untilted w.r.t. the ecliptic still). Where before the entire day-night terminator was smoothly approaching T = 0 from the day side, now this is true only at the poles! The integral of the polar area (for a given polar angle d\theta) is much smaller than the integral of the equatorial angle, and on top of that one now has a smeared out set of steady state temperatures that are all functions of azimuthal angle \phi and polar angle \theta, one that changes nonlinearly as you crank any of: Insolation, albedo, emissivity, \omega (angular velocity of rotation) and heat capacity of the surface.
And we haven’t even got an atmosphere yet. Or water. But at least up to this point, one can solve for the temperature distribution T(\theta,\phi,\alpha,S,\epsilon,c) exactly, I think.
Furthermore, one can actually model something like water pretty well in this way. In fact, if we imagine covering the planet not with air but with a layer of water with a blackbody on the bottom and a thin layer of perfectly transparent saran wrap on top to prevent pesky old evaporation, the water becomes a contribution to the thermal ballast. It takes a lot longer to raise or lower the temperature of a layer of water a meter deep (given an imbalance between incoming radiation) than it does to raise or lower the temperature of maybe the top centimeter or two of rock or dirt or sand. A lot longer.
Once one has a good feel for this, one could decorate the model with oceans and land bodies (but still prohibit lateral energy transfer and assume immediate vertical equilibration). One could let the water have the right albedo and freeze when it hits the right temperature. Then things get tough.
You have to add an atmosphere. Damn. You also have to let the ocean itself convect, and have density, and variable depth. And all of this on a rotating sphere where things (air masses) moving up deflect antispinward (relative to the surface), things moving down deflect spinward, things moving north deflect spinward (they’re going to fast) in the northern hemisphere, things moving south deflect antispinward, as a function of angle and speed and rotational velocity. Friggin’ coriolis force, deflects naval artillery and so on. And now we’re going to differentially heat the damn thing so that turbulence occurs everywhere on all available length scales, where we don’t even have some simple symmetry to the differential heating any more because we might as well have let a five year old throw paint at the sphere to mark out where the land masses are versus the oceans, and or better yet given him some Tonka trucks and let him play in the spherical sandbox until he had a nice irregular surface and then filled the surface with water until it was 70% submerged or something.
Ow, my aching head. And note well — we still haven’t turned on a Greenhouse Effect! And I now have nothing like a heuristic for radiant emission cooling even in the ideal case, because it is quite literally distilled, fractionated by temperature and height even without CO_2 per se present at all. Clouds. Air with a nontrivial short wavelength scattering cross-section. Energy transfer galore.
And then, before we mess with CO_2, we have to take quantum mechanics and the incident spectrum into account, and start to look at the hitherto ignored details of the ground, air, and water. The air needs a lapse rate, which will vary with humidity and albedo and ground temperature and… The molecules in the air recoil when the scatter incoming photons, and if a collision with another air molecule occurs in the right time interval they will mutually absorb some or all of the energy instead of elastically scattering it, heating the air. It can also absorb one wavelength and emit a cascade of photons at a different wavelength (depending on its spectrum).
Finally, one has to add in the GHGs, notably CO_2 (water is already there). They have the effect increasing the outgoing radiance from the (higher temperature) surface in some bands, and transferring some of it to CO_2 where it is trapped until it diffuses to the top of the CO_2 column, where it is emitted at a cooler temperature. The total power going out is thus split up, with that pesky blackbody spectrum modulated so that different frequencies have different effective temperatures, in a way that is locally modulated by — nearly everything. The lapse rate. Moisture content. Clouds. Bulk transport of heat up or down via convection. Bulk transport of heat up or down via caged radiation in parts of the spectrum. And don’t forget sideways! Everything is now circulating, wind and surface evaporation are coupled, the equilibration time for the ocean has stretched from “commensurate with the rotational period” for shallow seas to a thousand years or more so that the ocean is never at equilibrium, it is always tugging surface temperatures one way or the other with substantial thermal ballast, heat deposited not today but over the last week, month, year, decade, century, millennium.
Yessir, a damn hard problem. Anybody who calls this settled science is out of their ever-loving mind. Note well that I still haven’t included solar magnetism or any serious modulation of solar irradiance, or even the axial tilt of the earth, which once again completely changes everything, because now the timescales at the poles become annual, and the north pole and south pole are not at all alike! Consider the enormous difference in their thermal ballast and oceanic heat transport and atmospheric heat transport!
A hard problem. But perhaps I’ll try to tackle it, if I have time, at least through the first few steps outlined above. At the very least I’d like to have a better idea of the direction of some of the first few build-a-bear steps on the average temperature (while the term “average temperature” has some meaning, that is before making the system chaotic).
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Why are we worried about the temperature of the sphere. We live in the atmosphere near the surface of the sphere. Also, average global temperatures have no value other than for curiosities sake.
Too complicated. Start like this: Earth is on average warmer than Moon. Earth day (+20°C) is much cooler than Moon day (+130°C), so the Earth night (+10°C) is much, much warmer than Moon night (-230°C). Why?
Some say it is a thick arrow of IR radiation, blazing on the Earth surface from black cold sky. At least Kiehl-Trenberth diagram says so. That every-present beam of downward IR radiation is so powerful, that our night has 10°C instead of -230°C. Must be so, since our day is, cough cough, mightily cooled by abundant “greenhouse gas” in form of clouds, ice/snow and evaporation. So that invisible stream of energy, falling at our heads in a speed of light is at every moment warming the night surface by incredible 240°C!!! Dare you to switch it off for a moment, like hiding under a roof; you would freeze instantly! And what is even more awesome, the whole stream of energy, similar to heat wave produced by nuclear explosion or what, is just a less half of recycled outgoing radiation, since the night surface of 10°C, well, also radiates something upwards. It means, however, that the “something” leaving the night surface from under our feet is more than twice powerful as the night sky downward radiation! Are you roasting already? Feel the heat?
Sorry gents, this radiation nonsense is just nonsense. At night, I am warmed by a bulk atmosphere, nitrogen and oxygen, which is keeping the daily heat.
PS. Is there any consensus what the elephant in the room (nitrogen and oxygen warmed by conduction and convection from the surface warmed by Sun) actually do? If they radiate IR (as all matter with temperature >0K should do), good luck in recognizing the IR coming from one molecule of CO2, compared to 25,000 other molecules (this is the ratio of CO2 above the “safe” 350 ppm level). If they do not radiate IR, they simply keep the daily accumulated heat, working as a thick blanket.
PPS. How is that 17W in Kiehl-Trenberth diagram, assigned to thermals, calculated? Is it a physically reasonable number, compared to 333W of outgoing radiation from the surface?
Dr. Brown has done a good job of restating a very simple statement : The Earth is not a “theoretical Black body ” of course this was also stated by Gerlich and Tscheuschner in the abstraction of their paper (see below) in 2009.
Now lets see if Dr. Brown can come up with a similar analysis to show that the Hypotheses of the “greenhouse gas effect” is a fairy-tale – a hoax. below is a list of references for him to ponder.
List of references:
The paper “Falsification of the Atmospheric CO2 greenhouse effect within the frame of physics” by Gerhard Gerlich and Ralf D. Tscheuschner is an in-depth examination of the subject. Version 4 2009
Electronic version of an article published as International Journal of Modern Physics
B, Vol. 23, No. 3 (2009) 275{364 , DOI No: 10.1142/S021797920904984X, c World
Scientific Publishing Company, http://www.worldscinet.com/ijmpb.
Report of Alan Carlin of US-EPA March, 2009 that shows that CO2 does not cause global warming.
Greenhouse Gas Hypothesis Violates Fundamentals of Physics” by Dipl-Ing Heinz Thieme This work has about 10 or 12 link
that support the truth that the greenhouse gas effect is a hoax.
R.W.Wood
from the London, Edinborough and Dublin Philosophical Magazine , 1909, vol 17, p319-320. Cambridge UL shelf mark p340.1.c.95, i
The Hidden Flaw in Greenhouse Theory
By Alan Siddons
from:http://www.americanthinker.com/2010/02/the_hidden_flaw_in_greenhouse.html at March 01, 2010 – 09:10:34 AM CST
The below information was a foot note in the IPCC 4 edition. It is obvious that there was no evidence to prove that the ghg effect exists.
“In the 1860s, physicist John Tyndall recognized the Earth’s natural greenhouse effect and suggested that slight changes in the atmospheric composition could bring about climatic variations. In 1896, a seminal paper by Swedish scientist Svante Arrhenius first speculated that changes in the levels of carbon dioxide in the atmosphere could substantially alter the surface temperature through the greenhouse effect.”
After 1909 when R.W.Wood proved that the understanding of the greenhouse effect was in error and the ghg effect does not exist. After Niels Bohr published his work and receive a Nobel Prize in Physics in 1922. The fantasy of the greenhouse gas effect should have died in 1909 and 1922. Since then it has been shown by several physicists that the concept is a Violation of the Second Law of Thermodynamics.
Obviously the politicians don’t give a dam that they are lying. It fits in with what they do every hour of every day .Especially the current pretend president.
Paraphrasing Albert Einstein after the Publishing of “The Theory of Relativity” –one fact out does 1 million “scientist, 10 billion politicians and 20 billion environmental whachos-that don’t know what” The Second Law of thermodynamics” is.
ILEUniversity of Pennsylvania Law School
INSTITUTE FOR LAW AND ECONOMICS
A Joint Research Center of the Law School, the Wharton School,
and the Department of Economics in the School of Arts and Sciences
at the University of Pennsylvania
RESEARCH PAPER NO. 10-08
Global Warming Advocacy Science: a Cross Examination
Jason Scott Johnston
UNIVERSITY OF PENNSYLVANIA
May 2010
This paper can be downloaded without charge from the
Social Science Research Network Electronic Paper Collection:
http://ssrn.
Israeli Astrophysicist Nir Shaviv: ‘There is no direct evidence showing that CO2 caused 20th century warming, or as a matter of fact, any warming’ link to this paper on climate depot.
[1] [2] Slaying the Sky Dragon – Death of the Greenhouse Gas Theory [Kindle Edition]
Tim Ball (Author), Claes Johnson (Author), Martin Hertzberg (Author), Joseph A. Olson (Author), Alan Siddons (Author), Charles Anderson (Author), Hans Schreuder (Author), John O’Sullivan (Author)
Israeli Astrophysicist Nir Shaviv: ‘There is no direct evidence showing that CO2 caused 20th century warming, or as a matter of fact, any warming’ link to this paper on climate depot
Web- site references:
http://www.americanthinker.com Ponder the Maunder
wwwclimatedepot.com
icecap.us
http://www.stratus-sphere.com
SPPI
The Great Climate Clash -archives December, 2010 , G3 The greenhouse gas effect does not exist.( peer reviewed and revised but not yet released).
Wood is correct: There is no Greenhouse Effect
Posted on July 19, 2011 by Dr. Ed
Repeatability of Professor Robert W. Wood’s 1909 experiment on the Theory of the Greenhouse (Summary by Ed Berry. Full report here or here. & PolyMontana.)
by Nasif S. Nahle, June 12, 2011
University Professor, Scientific Research Director at Biology Cabinet® San Nicolas de los Garza, N. L., Mexico.
many others are available.
The bottom line is that the facts show that the greenhouse gas effect is a fairy-tale and that Man-made global warming is the World larges Scam!!!The IPCC and Al Gore should be charged under the US Anti-racketeering act and when convicted – they should spend the rest of their lives in jail for the Crimes they have committed against Humanity.
The only thing more dangerous than ignorance is arrogance.”
—Albert Einstein
“Democracy is two wolves and a lamb deciding what to have for dinner. Liberty is a well-armed lamb.” Benjamin Franklin
[1]HTML:
[2]HTML:
Worst of all, the Earth has no lid!
So, for example, for Earth we know that the average intensity absorbed is ~240 W/m^2 and the average emission is ~390 W/m^2 or so….
If this is true.
I ask.
? How many Earths are needed to increase the sun’s surface temperature in 100K???
John West says:
January 12, 2012 at 11:55 am
How can an increase in GHG mass in the atmosphere cause an increase in GHE (back radiation) prior to any significant atmospheric temperature increase if a temperature decrease (emitting from higher, colder position) reduces the radiance of the atmosphere? Until I see some evidence to the contrary, I maintain that no temperature increase is required in order to emit an additional amount radiation from GHG’s both down and up.
– – – –
John, think you hit it on the nose. One additional viewpoint I might add, the way I see it, is that in all aspects but one radiation in an atmosphere is but a fast conductor. The exception is radiation can leave the atmosphere into space of course. But within the thick of the gases, radiation performs everything conduction performs but on a larger, faster scale and depending on the concentration of other molecules (usually the same but not always) with the exact frequencies to absorb the radiation.
Radiation therefore allows an atmosphere to equalize faster that without it. I see like you seem to see that there is no magic concerning radiation at the surface-atmosphere interface. Radiation just bounces from molecule to molecule over many meters instead of directly from molecule to molecule as seen in conduction.
Mix that in with the thermalization, re-excitation and the equipartition points you made and you might see it the way I do. Phil seems to see radiation in a different manner, totally separate that the other means of transfer… like it had a magical aspect compared to conduction, I see none (but being able to leave that is).
I have a hard time to get others to view it that way, but that view is much simpler to visualize while remains proper in physics.
Earth’s baseline black-body model – “a damn hard problem”
And Willis quote from pg 3:
“But in practice, the fact that you can buy a handheld remote thermometer, which uses the strength of IR radiation plus the S-B equation to measure the temperature of common objects around us means that S-B almost holds almost everywhere. Most things radiate at a level which is quite close to their theoretical S-B radiation of epsilon sigma T^4.”
And post I didn’t post. Which could summed up as the temperature you take isn’t the energy radiated. It involved warm concrete and evaporation rate. But anyhow, that’s on my mind.
So there no doubt about S-B equation measuring temperature. No doubt about energy must balance- incoming energy “absorbed” must roughly equal out going radiation. If they don’t balance it means the planet is warming or cooling.
What we do know without doubt is the earth balance does not change in a day or week- the whole planet does not get warmer or cooler is short period time- it’s at most like .001 K for very fast warming or cooling globally if occurs in a less than week’s time
But as obviously know the each day it warms and cools- it’s always warming or cooling- it’s the sum total which isn’t changing- it’s warming in one part of planet and cooling at same time in another.
In post I didn’t post I was attempting to argue that a warmed piece sidewalk which was 20 C warmer than same sidewalk in the shade, was radiating significant amount energy and the shaded wasn’t radiating any or small amount. the proof was that if shaded the warm sidewalk and put few grams of water on it, it evaporate the water much quicker than sidewalk always in shade.
In other words I could measure how heat the warmed sidewalk emitted. Or something at temperature of 400 watts per meter [shaded] will evaporate less than warmed sidewalk which was emitting 500 watts. Or in other words I going to propose a test if the 400 watt surface could do work as compared something something emitting 100 watts more. 2 square meters at 400 watts “should” do more work than 1 sq meter at 500 watts? But it’s flawed because doesn’t make anything clearer. Hence the non post.
Or surface is covered little pyramids thereby at least doubling the surface area, come anywhere close to radiating twice the energy? it will radiate more, that pretty I am certain, but a lot more?
Just to be clear, if surface is in sunlight, and it’s reached about hot as it going to get, it will radiate the same amount energy it is receiving from the sun. So sidewalk in sunlight will radiate the solar energy- it will radiate 1000 watts minus maybe 10 watts it is absorbing [heat conducted thru concrete and very amount to ground below it]. So incoming sunlight 1000 watts, and sidewalk in sun radiating around 1000 watts. When you shade the sun and sidewalk is reflecting less sunlight, but continues to radiate around 900 watts of energy.- and this recently shaded sidewalk can lots of work. It has power, it has watts of energy- maybe roughly 100,000 watts seconds of work it can do.
The always shaded sidewalk won’t do work. Put both in space in which they can radiate to 2 K, and both can do work.
Or pour liquid nitrogen on either and they both can do work. But my point is the shaded sidewalk with same temperature as the air, doesn’t do work. So it can be said to be at 400 watts. But 400 watts per second of energy it is not emiting- it is possible to emit it, but it’s not doing it.
So of course this point, we get: “Of course, this is the greenhouse effect, you idiot!!!
Measure the sky it’s 400 watts and is warming the sidewalk or preventing it from radiating it’s energy!!!”
But this isn’t really true. “It” might doing a little bit.
You have similar thing if in space. Yes it cools, how much power does it cool at? It’s a question of the conduction rate of the material.
If the magical perfect bodybody, it’s not question- it radiates 400 watts of energy per second. But this concrete we talking about it, not magical material. The magical material isn’t just colored black, it conducts heat perfectly- which isn’t vaguely a descriptive of concrete. Copper or diamond get somewhat close to a blackbody- as far as conductivity.
Now, I can do better than a black body as far as losing heat/doing work. Liquid Nitrogen, will cool that sucker fairly fast, not immediately, but explosively. Simple water will also cool it fairly fast- and water in vacuum of space is probably better than liquid nitrogen.
One way of saying this is the sun in terms of radiating heat is pretty good, but what it heat up isn’t as good at radiating heat. And the closer you are the the sun the better it is at radiating- it heats things faster.
So Greenhouse gases and/or conduction of air might be slowing an shaded concrete to from cooling, but even in space it doesn’t radiate at 400 watts- it’s that temperature, but temperature can’t measure the work it does, different things at same temperature can do more work per square meter- and the fictional black body does the most work.
Let’s make a report to the policy-makers before we finish!
There was, but Lawrence’s Bedou reassembled it into a couple of muskets. And one ceremonial daggar.
[Yes, I know, wrong desert. But somebody did it!!]
😉
George E. Smith; says:
January 12, 2012 at 11:11 am
“…that instructs that radiation that it may not land on the surface, because that surface happens to be at a higher Temperature than was the emitting gas molecule; …”
Mr. Smith, it is agreed that the EM can land on a warmer surface the question is does it get absorbed, as some say, there by increasing the W/m^2.
Sir, if I have 2 torches at 1000 C and point one at a spot what is the max temperature that spot can get? If I then point the other torch at the same spot at the same time what is the max temperature the spot can get? When I remove one of the torches what is the max temperature the spot can get?
I was taught, years ago admittedly, that a higher energy state object does not absorb lower energy. Maybe poorly said but I think you understand.
George E. Smith; says:
January 12, 2012 at 11:11 am
So Thermodynamic Professor, whether or not one believes that the ordinary atmospheric mono or homo-diatomic gases: Argon, Nitrogen, Oxygen (maybe …..
Sorry but we have never managed to warm up anything with colder objects or gases, the nonsense you are talking about. This is based purely for Thermodynamic laws. It would of course be very nice if such unphysical [snip] happens, our power plant production costs would be much lower;)
Let me add more to your eq.
The Earth’s core is molten and heat rises to the surface unevenly. We have fewer data points on this heat transfer than on the solar flux. Mid ocean ridges are literally boiling with heat (trapped because the pressure can raise the temperature of the water WELL above 100°C (boiling at sea level).
No one has disproved that El Nina/El Nino are not actually due to fluctuations in heat from the dense number of ridges in that area of the Pacific. Speaking of Coriolis effects, why aren’t rotation directions of the PDO and ANO etc driven by super hot water coming from the depths instead of solar heating at the surface????
“The emission spectrum of the Earth from space is grey body with numerous missing bands which can be unambiguously assigned to the GHGs (CO2, H2O, O3, CH4 & N2O), the spectrum of the Earth absent those GHGs would be grey body but would have to have the same area under the curve which requires a lower temperature. Therefore there is a GHE due to the presence of those gases.”
That could also happen if the initial warming was from surface to atmosphere via conduction could it not ?
Thus there is a GHE effect but not necessarily caused by those gases.The energy that would have been in the missing wavelengths could just be offset by an increase in other outgoing wavelengths.No one is denying that GHGs radiate 50% upwards are they ?
Suppose that the radiative effect of GHGs were net zero because they send as much energy out of the system as they retain within the system. (non GHGs retain 100% within the system).
What does it matter if GHGs utilise different spectral bands to those used by the surface ?
They could be acquiring all of their energy from the other non GHG molecules which can be heated by conduction from the surface and would pass it on to the GHGs via conduction. Once the GHGs reach the ambient temperature for other molecules at the same height (via conduction) they cannot get any warmer from longwave coming up from the surface so they would have no more ‘blocking’ ability than the non GHGs already have (100%). Meanwhile they are busily radiating upward.
They may pass 50% of their energy back down again but by radiation rather than by conduction and unlike non GHGs that 50% passed down would be matched by 50% sent out of the system altogether which is something that non GHGs cannot achieve.
I think it is conduction intervening between radiation coming into the system and radiation going out of the system that creates the greeenhouse effect and not radiative physics.
How does the ovoid shape of the surface effect the energy model, the seasonal tilt angles do not have the same surface areas presented to the sun.
John West says:
January 12, 2012 at 11:55 am
That ignores the energy added by conduction. Because the amount of energy emitted is always greater than the amount absorbed, increasing greenhouse gases will always reduce the temperature of the atmosphere. (Does not apply above the troposphere.)
Tim Folkerts says:
January 12, 2012 at 10:49 am
I fully agree with points 1 thru 4, but 5 is a problem. First, what do you mean by “high”?
Below the tropopause? Above it? Also which GHG are you suggesting?
In general, it is my understanding that GHGs cool the atmosphere, with the obvious exception of the stratosphere. It is also my understanding that GHGs below about 2 km warm the surface, and that those higher up have no effect on the surface temperature.
Robert Brown (and others)
Thank you. It’s great to see fundamentals coming up for rethink with clarity. Two points
(1) Two others have referred to Miskolczi here, suggesting you might be interested to check him out. I second that. I still don’t understand his theory, but I do recognize that it has an extraordinarily close fit with actual measurements both from Earth and from Mars. This makes me think he is really onto something significant, if only he could be explained to duffers.
(2) What is the significance of the “W” shape temperature profile of our atmosphere? Is this prime evidence of the GHG effect of ozone formed at these heights? and by extension, proof of the GHG effect of CO2 which tends to lie low?
Robert Brown shows why he is one of the commentors I most admire here.
(So much so I’m willing to ignore he’s a Dukie.)
Hölder’s Inequality requires that the average temperature on a non-isothermal sphere at radiative equilibrium, assuming the same emissivity and incident power level, must be less than the average temperature of an isothermal sphere. That’s something that G&T do correctly ( http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1161v4.pdf Section 3.7.4 ).
As always, an awesome post (although I know of the inequality and derived a special form of it last week, I am infected with G&T’s skepticism about ALL of the physics now and want to see it all for myself). I’m about halfway through G&T, getting a bit bogged down in the rhetoric but looking forward to chapter 5 and the promised (hopefully correct) physics. I’ve already concluded that while top-of-atmosphere measurements do mean something with respect to the absorption properties of CO_2 (and probably with the warming) that a) it ain’t like “a greenhouse” except in the most metaphorical of senses; and b) the physics is way more difficult than even Caballero suggests. How it all works out — I’m open minded.
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Thank you. It’s great to see fundamentals coming up for rethink with clarity. Two points
Neither of which I’m prepared to answer. My reading list is (still) full to the brim, and I have no good idea of why there is a stratosphere and a troposphere and an exosphere and all that. I’ve read a few things that purport to explain parts of it, but none of them have completely convinced me, in part because I suspect one needs a “wholistic” explanation, not an explanation by parts.
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It is also my understanding that GHGs below about 2 km warm the surface, and that those higher up have no effect on the surface temperature.
Although there may be some surprising (?) evidence that water vapor content in the stratosphere may play some role. But separating cause and effect is difficult here. Relatively warm water vapor, very high up — what’s not to like?
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Lucy Skywalker says:
January 12, 2012 at 1:39 pm
That is caused by greenhouse gases. The tropopause is cold because the water vapor emission bands are transparent above that point. The primary greenhouse gas in the stratosphere is CO2 (380 ppm). Water vapor is 5 ppm and ozone is less than 1 ppm. CO2 in the stratosphere emits radiation toward the surface. At the tropopause, that radiation is absorbed by other CO2 molecules, those heat the local atmosphere, which then heats the water molecules, which finally emit the heat to space.
None of the stratosphere heat makes it below the tropopause because the air pressure makes the spectra bands more opaque as the pressure increases.
I have written a full description of this here.
How does the ovoid shape of the surface effect the energy model, the seasonal tilt angles do not have the same surface areas presented to the sun.
An excellent question. The answer is that as far as energy influx is concerned for the simple models, one has to consider the flux of the poynting vector (an integral over the surfaces) associated with the vector-directed intensity distributions. This really can’t be done by pretending that everything is one-dimensional as is commonly done (as G&T, linked above, point out). This makes the math considerably more difficult, but not intractable numerically if you know the shape and rotation and tilt and all that. Just a major pain of direction cosines, I guess.
Things get even nastier, as one might imagine, once you add a relatively thick atmosphere and a nice thick asymmetrically distributed ocean and mountains and plains and forests and rocks and swamps and ice and clouds and circulation. I’m waiting to see if G&T have any suggestions for a decent decomposition of the problem, but I’m prepared for the answer to be “no”.
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Joel Shore says:
January 12, 2012 at 9:14 am
…So, for example, for Earth we know that the average intensity absorbed is ~240 W/m^2 and the average emission is ~390 W/m^2 or so… [as] in fact the emissivity of the Earth is very close to 1 over the relevant wavelengths.
In fact, we do not know this, because we have not tested under conditions reflecting the true environment.
B.Klein says:
January 12, 2012 at 12:49 pm
“After 1909 when R.W.Wood proved that the understanding of the greenhouse effect was in error and the ghg effect does not exist.”
He found that it did not exist in a laboratory setting. But, in a dynamic atmosphere which results in Doppler broadening of the spectral absorption bands, any GHG effect is likely more pronounced.
Both of these evidences, both pro- and con-, rely on laboratory experiments which do not represent the actual physical environment.