As a result of discussions on Willis Eschenbach’s toy planet ‘steel greenhouse’, I took a look at what Wikipedia has to say about ‘thermalisation’ of radiaton. The answer is, remarkably little. Intrigued, I turned to Wikipedia’s page on the Greenhouse Effect to find the references to physics texts explaining how the physics of the greenhouse effect works. Surprisingly, it refers only to the IPCC, rather than any work by physicists. Under the section on ‘Mechanism’ we get this:
Within the region where radiative effects are important the description given by the idealized greenhouse model becomes realistic: The surface of the Earth, warmed to a temperature around 255 K, radiates long-wavelength, infrared heat in the range 4–100 μm.[19] At these wavelengths, greenhouse gases that were largely transparent to incoming solar radiation are more absorbent.[19] Each layer of atmosphere with greenhouses gases absorbs some of the heat being radiated upwards from lower layers. It re-radiates in all directions, both upwards and downwards; in equilibrium (by definition) the same amount as it has absorbed. This results in more warmth below. Increasing the concentration of the gases increases the amount of absorption and re-radiation, and thereby further warms the layers and ultimately the surface below.[8]
I’ve italicised the arguments by assertion. Assuming that reference [8] linked above would justify this unsupported assertion, I scrolled down to see which physics text it would lead me to:
8 Intergovernmental Panel on Climate Change Fourth Assessment Report. Chapter 1: Historical overview of climate change science page 97
So I went to AR4 Ch 1 P97 to see which physics texts we’re referred to there. I found this unsupported statement:
The reason the Earth’s surface is this warm is the presence of greenhouse gases, which act as a partial blanket for the longwave radiation coming from the surface. This blanketing is known as the natural greenhouse effect.
Blanket? Blanketing?? What kind of unscientific parlance is this? No numbered references, no footnotes, no nothing. Even worse than Wikipedia’s effort. I scrolled down to the references section at the end of the chapter and found a list of several hundred papers, listed in alphabetical order by Lead author. Useless.
So where’s the beef? Perhaps some talkshop readers can help here. Where is the ‘official physics’ of the Greenhouse Effect to be found?
Tallbloke's Talkshop 
According to this argument doubliing CO2 would double the lapse rate ! It is simply wrong.
Indeed – Wikipedia is saturated with IPCC stuff in many pages about aspects of climate etc. BUT one should not complain about that – if you have the knowledge to correct anything in Wikipedia just change it! That is the whole point in wikis. I have written and have edited many pages and when I have been wrong, corrections have been made and supported by other editors. ANYONE can edit Wikipedia – so please, if you can better any article, go and do it!
I would have purged all the secondary stuff and unsupported from IPCC had I the knowledge to do so long ago. A concerted effort by sceptics could wipe the floor of unsupported assertions and would be applauded by everyone in the Wiki community. Please go to it!
‘Surprisingly, it refers only to the IPCC’
Is it really a surprise?
‘Where is the ‘official physics’ of the Greenhouse Effect to be found?’
It doesn’t seem to work like that – more like the many-headed beast of legend…
http://en.wikipedia.org/wiki/Lernaean_Hydra
Just waiting for Heracles to turn up now (not Hercules as Wikipedia twice says).
I should have added that there cannot be an ‘official’ page for anything in Wikipedia – that’s why the whole project is under constant threat by the bureau in various countries.
Perhaps this article will help:
http://greenhouse.geologist-1011.net/
Abstract:
This article explores the “Greenhouse Effect” in contemporary literature and in the frame of physics, finding a conspicuous lack of clear thermodynamic definition. The “Greenhouse Effect” is defined by Arrhenius’ (1896) modification of Pouillet’s backradiation idea so that instead of being an explanation of how a thermal gradient is maintained at thermal equilibrium, Arrhenius’ incarnation of the backradiation hypothesis offered an extra source of power in addition to the thermally conducted heat which produces the thermal gradient in the material. The general idea as expressed in contemporary literature, though seemingly chaotic in its diversity of emphasis, shows little change since its revision by Svante Arrhenius in 1896, and subsequent refutation by Robert Wood in 1909. The “Greenhouse Effect” is presented as a radiation trap whereby changes in atmospheric composition resulting in increased absorption lead to increased surface temperatures. However, since the composition of a body, isolated from thermal contact by a vacuum, cannot affect mean body temperature, the “Greenhouse Effect” has, in fact, no material foundation. Compositional variation can change the distribution of heat within a body in accordance with Fourier’s Law, but it cannot change the overall temperature of the body. Arrhenius’ Backradiation mechanism did, in fact, duplicate the radiative heat transfer component by adding this component to the conductive heat flow between the earth’s surface and the atmosphere, when thermal conduction includes both contact and radiative modes of heat transfer between bodies in thermal contact. Moreover, the temperature of the earth’s surface and the temperature in a greenhouse are adequately explained by elementary physics. Consequently, the dubious explanation presented by the “Greenhouse Effect” hypothesis is an unnecessary complication. Furthermore, this hypothesis has neither direct experimental confirmation nor direct empirical evidence of a material nature. Thus the notion of “Anthropogenic Global Warming”, which rests on the “Greenhouse Effect”, also has no real foundation.
MS: I added info to a wiki page – it got reverted.
I created a wiki page with lots of supporting links – it got deleted
There is a mafia of the warmista on Wikipedia and I can’t see how to dislodge them when thy know how to play the system better than we do.
Some of the assumptions about the “Greenhouse effect” comes from the poor quality book “The Physics of Atmospheres” by (Sir ) John T.Houghton first published in 1977. This contains snippets of information which could have been plagerised from other text books (eg section 1.4 P4 is titled “Adiabatic lapse rate” and is likely to have been copied from elsewhere with no attribution.but it is not taken anywhere and then on P16 the greenhouse effect on Venus, (now discredited), is mentioned without consideration of the lapse rate.) Throughout the book there are assumptions which are not explained and some are clearly wrong or used in the wrong context. Houghton has a chapter (6) on “Clouds” but only 5.5 pages long.. In section 11.8 “Inclusion of clouds” the following is stated “The presence of cloud exerts a profound influence on both the short-wave and log-wave radiation fields The cloud field, however, is often very complex ——-simplification is therefore necessary in the model description of clouds and their effect on the radiation field” My impression is that Houghton really does not understand the complex science involved. He has read selected texts, extracted bits and included a range of subjects to fill out the book and to give the impression that he knows a lot. I can find no references to any papers or books produced by engineers and the only mention of an engineer comes in a small section on the Reynolds number (9.1) (named after Osborne Reynolds) which is not used or mentioned elsewhere in the book.(I suggest that this has been copied and that he does not understand its use)
Here are some posts about the Greenhouse effect by Prof Claes Johnson http://claesjohnson.blogspot.com.au/search/label/greenhouse%20effect
His comments about Modtran and Hitran are worth noting. I do not think anyone else has shown the model of these maybe/are giving the wrong result.
The Wikipedia entry on Greenhouse Effect mechanism includes this phrase
radiates long-wavelength, infrared heat
Radiation is not heat.Nasa also thinks it is and promotes it view to children
http://www.nasa.gov/audience/foreducators/topnav/materials/listbytype/Earths_Energy_Budget.html
Radiation can cause heat when absorbed by matter. That is what I taught as a high school science teacher for 40 years.
Maybe I should write to Nasa and complain
Roger C: Yes, I do wonder what they mean by ‘thermal radiation’ too. Is this different from ‘ionising radiation’ or is it more a question of what radiation bumps into? If so it seems to beg the question: How does ‘thermal radiation’ from cold gas ‘thermalise’ warm ground?
It also includes this phrase:
It has also been demonstrated experimentally (R. W. Wood, 1909) that a “greenhouse” with a cover of rock salt (which is transparent to infra red) heats up an enclosure similarly to one with a glass cover. Thus greenhouses work primarily by preventing convective cooling
Repeat: convective cooling.
If one looks at the avalable high detail infrared pictures from space it becomes clear that there is not much scattering or interception of the photons by co2 or anything else except clouds. Are these backradiation senarios calculated by assuming most infrared is intercepted as it appears that most of it is able to escape unhindered? Even those few that are absorbed and re-emitted randomly are more likely to be intercepted again under an increasing co2 scenario and the whole thing becomes a toss of the coin affair where the law of averages will equal it all out so that no change in back radiation should occur.
Yes a slight lag may happen but this would be undetectable as these processes are happening very quickly.
“Where is the ‘official physics’ of the Greenhouse Effect to be found?”
Yeah, a very good question to ask. I am a physicist, but none of the current explanations – be it for the existence of a greenhouse effect, or against it – has so far convinced me to any degree.
There is a work by Prof Heinz Hug (unfortunately only in German, downloadable here: http://www.eike-klima-energie.eu/fileadmin/user_upload/Bilder_Dateien/HUG_THE_ein_Artefakt_II/Hug-EIKE-Artefakt_II-1.pdf) showing data he had measured – gosh – himself on the absorption of CO2 in the central wavelength of ~15um and side bands. He determined the molar extinction coefficient to be 20,2 m2 mol-1 for the central wavelength.
This means that from the radiation emanating from the ground, about half of it will already be absorbed at the height of your belly button! Since the lifetime of the excited state of the CO2 molecule is in the order of milliseconds for re-radiation, but in the order of only nanoseconds for de-excitation by collision, it is about a million times more likely that the absorbed energy is thermalized (i.e. converted to heat) by collision than that it is re-radiated. Hence that thermal radiation from the ground is absorbed by >>99% in the first 10 meters of atmosphere. The atmosphere in effect is pitch black for this radiation, and it had been even for CO2 at a tenth or less of its present concentration.
Reversing the perspective, it means that any “back-radiation” reaching the ground cannot come from anything higher than the first few meters! Since the atmosphere becomes “thinner” with height it means that the reach will be a bit longer the higher we go, but given the dimensions of the atmosphere basically all such radiation is absorbed in the vicinity of it origin. Very high up (~ stratosphere) half of the radiation might escape into space, but the part going downwards is absorbed and then thermalized soon, never reaching the ground.
Adding other greenhouse gases, like water vapour, makes the discussion more complicated, but a similar pitch-blackness of the atmosphere is true for water vapour as well.
A further complication arises from even the IPCC acknowledging that it is only the side bands “in particular around 13 7 and 16 (im” [sic] (see page #49, http://www.ipcc.ch/ipccreports/far/wg_I/ipcc_far_wg_I_full_report.pdf ), which are relevant. Since their extinction coefficient is lower that radiation goes for a longer distance, before being thermalized, and might actually reach the ground. But then their lower extinction coefficient means they are less relevant for absorption also.
In the discussion of the greenhouse effect as a radiative property, it seems that the longer range of the side bands is used with the absorptive property of the central band. That is obviously improper.
I’d agree that thermal radiation from the ground is absorbed by CO2, and this results in a heating of the air masses, which are then by convection rearranged to form the proper adiabatic profile. That warmed-up air will then be warming the surface. So there would be some warming.
But the question remains whether retention of radiation near the ground in the form of heat energy is the same / or more / or less than the loss of energy into space by radiation from the upper atmospheric layers.
So is there actually a Greenhouse effect? I don’t know.
“So where’s the beef? Perhaps some talkshop readers can help here. Where is the ‘official physics’ of the Greenhouse Effect to be found?”
Well, the gospel starts with idea that earth should be 33 C cooler than it is, and this 33 C warmer
average temperature can only be caused by greenhouse gases.
So the ‘official physics’ would using a blackbody model [I would say perverting it] to reach conclusion that Earth “should be” precisely 33 C cooler than it is.
The other ‘official physics’ is determining what greenhouse gas are adding this warming.
And this is a very vague approximation. As indicated by wiki:
“Water vapor H2O 36 – 72%
Carbon dioxide CO2 9 – 26%
Methane CH4 4 – 9%
Ozone O3 3 – 7% ”
http://en.wikipedia.org/wiki/Greenhouse_gas
So the “official physics” claims absolute certainty regarding the idea that earth should be
33 C cooler than it is. And has no precision in regards how much any particular greenhouse gases are making up for this “lost” 33 C.
With a certainty of conviction that it *has to be* solely greenhouse gas doing this
warming of 33 C.
Roger, I would like to suggest something to make this discussion more effective. There are different versions of the “greenhouse effect” around, I am familiar with 3 of them. I suggest we focus first on the IPCC version and ignore the others for a while, because it is the IPCC version that is politically relevant. Proving that this IPCC version is false or unsupported by real science would be an important step to cope with the climate scare.
Ulrich S: Welcome, and thanks for your contribution. Please stay around, I’m sure people will want to discuss what you have written with you.
I’ve always found the “absorption from the surface, back radiation” explanation of the greenhouse effect, while valid, to be cumbersome to explain and understand.
My alternate explanation, which is just as valid, is that by absorbing and later reradiating the outgoing longwave IR, the greenhouse gasses slow down the emission of longwave radiation as it passes from the surface of the earth into space. The more greenhouse gasses, the more the atmosphere slows the outgoing radiation. The slower the outgoing radiation, the more heat the atmosphere contains, and the higher the heat content, the higher the temperature.
Think of a stream flowing into a pond, and out again at the other end–same flow rate and volume in and out. If you dredge the pond deeper, the inflow and outflow remain equal at equilibrium, but it holds more water, and the bottom pressure is greater.
“There is a mafia of the warmista on Wikipedia and I can’t see how to dislodge them when thy know how to play the system better than we do”.
How true- and the most likely culprit is William Connoley
http://en.wikipedia.org/wiki/William_Connolley
He also writes his own alarmist blog.
http://scienceblogs.com/stoat/
“This means that from the radiation emanating from the ground, about half of it will already be absorbed at the height of your belly button! Since the lifetime of the excited state of the CO2 molecule is in the order of milliseconds for re-radiation, but in the order of only nanoseconds for de-excitation by collision, it is about a million times more likely that the absorbed energy is thermalized (i.e. converted to heat) by collision than that it is re-radiated. Hence that thermal radiation from the ground is absorbed by >>99% in the first 10 meters of atmosphere.”
Well difference between millionth of second and billionth of second is of order of 1000, not a
million.
But wiki says:
“When a molecule absorbs energy, as in the technique of molecular fluorescence, the lifetime of the excited state is ~10−^12 sec.”
http://en.wikipedia.org/wiki/Thermalisation
Which is a trillionth of second. Which is also order of 1000 difference.
But I don’t see how/why making a molecule glow, causes a molecules to increase it’s velocity or that every collision could do this.
So I don’t see why happens at all. And don’t why it would happen at every collision even if it could somehow happen. And if it did happen not sure why it doesn’t slow the kinetic motion
of gas as much as it increases the kinetic motion of gas molecules.
I do tend to agree that greenhouse gases if they warm, then there would be greatest possibility to warm at low elevation.
One possibility I thought is near the ocean surface. One has water vapor entering and exiting water constantly. And can occur very near the surface- a mm or so. And it seems a glowing gas molecule re-entering water would warm the water.
Of course there are other surfaces of water- such clouds and dew and simply wet surfaces.
Other than this I think greenhouse gas have most chance to warm near the surface, simply because the chance of re-radiated photon of reaching the surface or a surface is higher.
The higher it is, the lower the horizon and greater distances involved for a random 360 degree direction it can could travel before reaching a surface.
But in any case it seems to me the effect of all greenhouse gases seems at best to only do small amount warming- though it’s possible they do a smaller amount of cooling.
ulrich steiner says:
“Hence that thermal radiation from the ground is absorbed by >>99% in the first 10 meters of atmosphere.”
Hello, Unrich. Your explanation is correct as far as it goes, but let’s go to the next step. All outgoing LW radiation is absorbed in the first 10 meters of atmosphere, and mostly thermalized. However, that lowest 10 meters itself is a thermal body which radiates LW radiation, approximately half outward to be absorbed by the next 10 meters of atmosphere, and so on many times to the edge of space.
Now, let’s increase the concentration of GH gasses. That would cause the initial absorption height to decrease, let’s say to 9 meters. Therefore, there would be more of these total absorption bands the energy must get through to reach space. So the heat content of the atmosphere is somewhat higher, therefore the temperature is somewhat warmer.
As I said in my previous post, I think of the “greenhouse” atmosphere as slowing the flow of outgoing IR radiation as it passes from the surface back into space.
Ed
All of this is pitiful. It is not about slowing down longwave radiation passing from the surface to space; it is about what governs the bulk transferral of heat from the surface to space, and that is essentially just the hydrostatic, vertical temperature lapse rate. You should all know by now that a proper Venus/Earth temperature comparison shows that increasing the CO2, all the way from .03% (on Earth, when the Standard Atmosphere was first recognized) to 96.5%, has no effect on the atmospheric temperature. The temperature vs. pressure (T-P) curves of Earth and Venus are right on top of each other (above and below the cloud layer on Venus), when just the effect of their different incident solar intensities–due only to their different distances from the Sun–is removed. That result is the definitive fact There is NO greenhouse effect, defined as an increase in atmospheric temperature due to an increase in atmospheric carbon dioxide (what is being promulgated by climate scientists, who are all incompetent).
gbaikie says:
“I don’t see how/why making a molecule glow, causes a molecules to increase it’s velocity or that every collision could do this.”
The bonds between the atoms in a molecule are somewhat elastic, like springs, and with the atoms acting like weights at opposite ends of these springs, every molecule has at least one characteristic resonant vibrational frequency. Most molecules have many different resonant frequencies, depending on vibration modes, etc.
CO2 molecules have a resonant frequency that corresponds to 15 micro meters (LWIR). When it encounters a photon of IR energy at that wavelength, it readily absorbs it and begins vibrating faster. Now, there are two ways it can lose that energy again. First, It can spontaneously re-emit IR energy at the same frequency, and lose that extra vibration. Second, (and more likely), when it bumps into another molecule, that extra vibration gives the collision a little extra “kick”, and both molecules move away a little faster. Faster molecules within a fluid equals higher heat energy. At this point, the original IR has become thermalized.
Ed
ulrich steiner says:
March 13, 2013 at 12:47 pm
There is a work by Prof Heinz Hug (unfortunately only in German, downloadable here: http://www.eike-klima-energie.eu/fileadmin/user_upload/Bilder_Dateien/HUG_THE_ein_Artefakt_II/Hug-EIKE-Artefakt_II-1.pdf)
===========================================================
To find the English version you have to search for the URL “http://www.john-daly.com/artifact.htm” here: http://archive.org/web/web.php . Then a calendar will appear and an earlier version can be chosen.
No, harrydhuffman, this is not pitiful.
1. There is a temperature effect due to the weight and pressure gradient of the atmosphere.
2. Certain gasses can and do absorb longwave infrared radiation and thermalize that energy in an atmosphere.
3. There is energy constantly flowing into the earth-atmosphere system from the sun, and out again via IR.
This is a dynamic, interconnected process that does not lend itself to piecewise or static analysis. If you concentrate on only one aspect of the process, or limit yourself to static analysis, it’s easy to convince yourself that the other parts are not important or don’t exist, but you’re only fooling yourself.
Ed Fix says:
March 13, 2013 at 2:15 pm
The greenhouse effect does not lend itself to analysis.
Very true. So it is not science. I have have read dozens of explanations and calculations of GHE, all different. Greenhouse effect theory is like Al Qaeda a franchise business. Only more dangerous.
Ed Fix says:
“… that lowest 10 meters itself is a thermal body which radiates LW radiation, approximately half outward to be absorbed by the next 10 meters of atmosphere, and so on many times to the edge of space. ”
You are describing the “Radiation Transport” model from an atmospheric layer to the next, which is indeed used to explain the Greenhouse effect with the so called Back-Radiation. But this is a model, which I think is not applicable to the atmospehere. It was developed for a plasma, at temperatures of hot stars, like the sun.
As you yourself are describing the thermalization in a later reply of yours in this same threat, you would have to postulate that a CO2 molecule has the same likelihood of loosing its energy gained by absorbing a photon to a collision, as it has to become excited by a collision and loosing this energy by radiation. But as i said, the liftetime of the excited state before radiating is in millisecond, while collisions occur within nanosecond.
The net effect is thermalization, and no radiation transport. Hence no backradiation.
Ed Fix says:
‘The more greenhouse gasses, the more the atmosphere slows the outgoing radiation. The slower the outgoing radiation, the more heat the atmosphere contains, and the higher the heat content, the higher the temperature.’
Where’s the evidence of that actually happening, let’s say this century? No temperature rise between 1940 and 1975 either. Invoking aerosols or ‘temporary’ natural effects seem like a fudge to me.
Carbon dioxide absorption in the near infra-red
Click to access FP-1.pdf
Ulric Lyons says:
“Carbon dioxide absorption in the near infra-red
http://jvarekamp.web.wesleyan.edu/CO2/FP-1.pdf”
Interesting work, however this is about the “Near IR” of wavelengths from 1.4-2.1 micrometer. Hence it is relevant for the incoming solar radiation, but not for the outgoing thermal IR. The latter at wavelengths of >10 micrometer.
Ed Fix– If this is true then surely we would not be able to take detailed infrared images of the surface as we can. It would be like looking through a fog, or what am seeing that is wrong?
March 13, 2013 at 10:12 am – ‘Just waiting for Heracles to turn up now’
Right on cue, FOIA is back 😉
ulrich steiner says:
“Hence it is relevant for the incoming solar radiation..”
And interesting how big the ~1400nm absorption is compared to other sources.
Then what exactly is shown by the nighttime IR camera shots we frequently see on TV, where animals are clearly visible against the shadowy trees in the background, at a distance of easily 1/2 a mile. Seems like a lot more than 10 meters.
mike says:
“If this is true then surely we would not be able to take detailed infrared images of the surface as we can.”
Hi, Mike–
At the 15 micrometer CO2 absorption wavelength, we certainly cannot observe the earth’s surface from space. Infrared cloud images, for instance, are taken at the 4 micrometer wavelength. http://www.weather.gov/satellite
The portion of the electromagnetic spectrum we call “infrared” covers a lot of wavelength space–very much more than visible light. Here’s a look at earth’s emission spectrum.
Ed
PS. It looks like Climategate III has taken a lot of wind out of this discussion.
Ed: PS. It looks like Climategate III has taken a lot of wind out of this discussion.
Keep going, I will be taking it slowly with the archive. This is an important thread and I value your knowledgeable input. – Rog
steveta_uk says:
“Then what exactly is shown by the nighttime IR camera shots we frequently see on TV, where animals are clearly visible against the shadowy trees in the background, at a distance of easily 1/2 a mile. Seems like a lot more than 10 meters.”
Pay attention to the wavelengths, we are talking about. I recently toyed with IR illumination for such IR cameras for a night time nature observation, so I know that LEDs with a wavelength of 850 to 950 nanometer do work, available e.g. at this electronic supplier http://www.conrad.de/ce/de/product/183338/Infrarot-LED-Kreativ-Set-S081-Kemo-S081-Infrarot?queryFromSuggest=true. The shorter wavelenght ones do emit a faint red glow, while the others remain invisible to us. The others are mostly used in TV remote controls.
However, this range of wavelengths is far, far away from the 15000 nanometer of the CO2 absorption band I have talked about! It is the nature of gases that they absorb – at least within the wavelenghts relevant here – only in discrete lines, and not in a continuum, like blackbodies do. You see in the picture “Bild 2” of the paper by Heinz Hug I had quoted in my first post that at 15mikrometer (wavenumber 667) the atmosphere is more or less opaque, while at wavenumber 1100 (~ 11mikrometer) it is fully transparent.
Taking the link from above http://jvarekamp.web.wesleyan.edu/CO2/FP-1.pdf you see no absorption line for CO2 at shorter than 1400 nm. The IR cameras will probably work just fine in a pure CO2 atmosphere.
And indeed, when you take pictures of earth from space at the 15mikrometer wavelenght, you won’t see the ground. Just a white disk the size of earth.
Ed Fix says: “The more greenhouse gasses, the more the atmosphere slows the outgoing radiation.”
I use that model, too. I call it the “Pin Ball Effect”. The ball goes straight in without let or hindrance then is obstructed by all kinds of stuff on the way out.
Works for me!
ulrich steiner says:
March 13, 2013 at 6:37 pm
Thermal radiation is a result of temperature. So a case could be made that the 15 mirco radiation of CO2 is mechanical not thermal since it must by configuration emit at that frequency. Therefore if not themal it will not transfer heat to anything.
I think Ulrich Steiner has this about right. The radiataive transfer equations were developed to describe stars where radiation dominates heat transfer in plasmas. This is not the case on Earth where convection and latent heat dominate heat transfer through the atmosphere. This is why the adiabatic lapse rate depends only of the specific heat of the component gases and gravity. There is thermalizing of IR radiation by CO2 and H2O, howevre this does not slow down heat loss it just changes the balance. The atmosphere is stable at the ADR or including latent heat at the ELR. So what is the greenhouse effect ?
The mix of GHGs determine the effective height for each wavelength where the mean free path for photons becomes greater than the top of the atmosphere. Here radiation can escape to space and balance incoming solar energy. Below this level all temperatures, including that at the surface are only determined by thermodynamics (environmental lapse rate). Radiative transfer contributes about 1/3 of the thermal heat in the atmosphere. Convection and evaporation contribute about 2/3 generating the lapse rate
So the greenhouse effect is mis-named. It has nothing to do with blankets or with back radiation. The net effect of GHGs is to essentially to determine the height of the tropopause. This is where IR radiation to space dominates over convection and the lapse rate stops. The altitude of the tropopause determines surface temperature, because the effective temperature of the Earth as seen from space is invariant. It is total GHGs which determine the tropopause so H2O may well react to offset any human increases in CO2.
“Ed Fix says:
March 13, 2013 at 1:58 pm
gbaikie says:
“I don’t see how/why making a molecule glow, causes a molecules to increase it’s velocity or that every collision could do this.”
The bonds between the atoms in a molecule are somewhat elastic, like springs, and with the atoms acting like weights at opposite ends of these springs, every molecule has at least one characteristic resonant vibrational frequency. Most molecules have many different resonant frequencies, depending on vibration modes, etc.
CO2 molecules have a resonant frequency that corresponds to 15 micro meters (LWIR). When it encounters a photon of IR energy at that wavelength, it readily absorbs it and begins vibrating faster. Now, there are two ways it can lose that energy again. First, It can spontaneously re-emit IR energy at the same frequency, and lose that extra vibration. Second, (and more likely), when it bumps into another molecule, that extra vibration gives the collision a little extra “kick”, and both molecules move away a little faster. Faster molecules within a fluid equals higher heat energy. At this point, the original IR has become thermalized.”
The muzzle velocity of black powder musket is 120 m/s and modern high power rifles achieve 1,700 m/s:
http://en.wikipedia.org/wiki/Muzzle_velocity
Atmospheric air molecules have averaged velocity of about 400 m/s. Air molecules are exchanging momentum, as do billiard balls or Newton’s cradle. Molecules are better at transfer momentum
than anything made from a a bunch molecule, such as a billiard ball. They can collide at very high velocity without losing their kinetic energy. And this is part of the ideal gas law, ideal gases are considered to be exchanging energy without loss.
What you saying is that CO2 in a warm environment where there is IR radiation, are increasing their velocity- they are accelerated by certain wavelength of IR.
To accelerate anything one needs force [in a direction] and time.
“In physics, acceleration is the rate at which the velocity of a body changes with time. In general, velocity and acceleration are vector quantities, with magnitude and direction, though in many cases only magnitude is considered (sometimes with negative values for deceleration).”
http://en.wikipedia.org/wiki/Acceleration
Sunlight can impart the velocity of it’s photon to something like a solar sail- it’s a transfer of the photon momentum and is in a certain direction or vector. And if the sail reflect the photons one gets twice the momentum as compared to absorbing the photons.
“The momentum of a photon or an entire flux is given by p = E/c, where E is the photon or flux energy, p is the momentum, and c is the speed of light. At 1 AU the solar power flux density is about 1370 W/m2, resulting in a pressure under:
perfect absorbance: F = 4.57 μN per square metre (4.57 μPa)
perfect reflectance: F = 9.13 μN per square metre (9.13 μPa)”
http://en.wikipedia.org/wiki/Solar_sail
So solar sail provide very low acceleration- 9.13 millionth of newton per square meter of
1370 watts. A newton is about the force to lift a 100 grams in 1 gee
environment, holding up 100 grams against earth’s gravity is an accelerated force.
So solar sails provide little acceleration but if given enough time with constant acceleration
one could achieve velocities of around 1/10 the speed of light [in theory].
Now this different than what you saying but it provides some idea of how energy one can
get from radiation as related to converting it into kinetic energy.
It seems if CO2 [and other greenhouse gases] captures this radiant energy and convert to kinetic energy one could make some kind of machine to capture this energy.
That tanks of CO2 would get warmer than tanks of Oxygen.
And if you believe that there is back radiation which has a significant amount of energy, one could harvest this energy.
According to Trenberth energy budget there is twice as much watts per square meter of back radiation as compared to solar energy
Average solar is 161 W/m-2 and surface radiation is 396 W/m-2 with back radiation of
333 W/m-2
Solar panel capture about 20% of the solar energy. If more half radiant energy is converted to kinetic energy, then that’s starting with +50% efficiency. If one then ran it thru turbine, one might get around 25% efficiency in terms of making electricity.
The major problem with such a scheme is I have never heard of greenhouse gases being unstable in terms of it’s storage temperature.
This post determines where the often quoted 3.7 W/m2 comes from http://claesjohnson.blogspot.com.au/2013/03/the-fabrication-of-co2-alarmism-decoded.html#comment-form
It is modeled and not based on experimental data and if you read some of the early post on the same subject. The model is wrong.
The whole alarmism about CO2 is based on incorrect assumptions by people who do not understand the technology. No conspiracy just incompetence and stupidity by people who should never have received recognition.
I can’t believe that we continue to debate this. Clearly there are various views, sincerely held. In the old days, when I was boy, people would say, “Right then, let’s conduct an experiment”.
Why is no one considering a test, using columns of air and 100% CO2? Easy!
C’mon you University professors; have your grad students do something useful for a change!
JohnG, excellent, excellent article!
http://greenhouse.geologist-1011.net/
They are saying so many things I have come to realize, now I have a place to point complete with very good references on each and every conclusion that they make. Thanks.
gbaikie says:
“Well difference between millionth of second and billionth of second is of order of 1000, not a
million.”
Ahem, a millisecond is 10⁻3 sec, a nanosecond is 10⁻9 sec. The factor between is 10⁶. or a million!
“cementafriend says:
March 14, 2013 at 4:15 am
This post determines where the often quoted 3.7 W/m2 comes from http://claesjohnson.blogspot.com.au/2013/03/the-fabrication-of-co2-alarmism-decoded.html#comment-form
It is modeled and not based on experimental data and if you read some of the early post on the same subject. The model is wrong.”
Even if their modeling was correct, it doesn’t seem like much effect.
That graph indicates our atmosphere isn’t a pea soup to infrared- rather it’s almost equal in transparency as the atmosphere is to sunlight.
It seems to me an atmosphere comprised solely of non-greenhouse gases [say, just nitrogen gas]
but same amount atmosphere as Earth’s atmosphere. And so one could therefore say “completely transparent”, still stops significant amount of sunlight from reaching the surface. Or if we had atmosphere completely transparent to infrared radiation, it would still block some of infrared.
Some parts of infrared radiation spectrum would more diffused by this transparent atmosphere and all of infrared spectrum would to some extent would be diffused.
Or no substance is completely transparent is light is passing thru it if passing thru a lot of it.
Or fiber optics fiber designed to very transparent for certain wavelength has limit to the length a laser can transmit signal thru it- as would any atmosphere.
gbaikie says:
“But wiki says:
“When a molecule absorbs energy, as in the technique of molecular fluorescence, the lifetime of the excited state is ~10−^12 sec.””
First, we are not dealing with fluorescence in the discussion of radiative transfer by CO2 molecules, and second there are different lifetimes involved.
Fluorescence is a form of photo-luminescence. Phosphorescence is another one. The latter is being used e.g. for those Glow-in-the-Dark stickers, you can buy in toy stores, and you see right here that lifetimes can reach into the many minutes! Though typical fluorescence molecules seem to have lifetimes in the nanosecond (10^⁻9 sec) range, I guess you can find fluoro-/phosphorophores covering the whole range from nanosecond to minutes.
Common to both is that you need to excite with light of a higher energy than is later emitted. For example, illuminating a Glow-in-the-dark sticker with red light will not yield an emission of green light; illuminating with UV light would do! So there is some energy loss in the process: upon the initial absorption of a photon, the molecule is in an excited state. It relaxes from that state within picoseconds (10^-12 sec) to a lower excited state – this is the fast process mentioned in your Wiki quote. But this 2nd, lower excited state then decays with the nanosecond to minutes time scale.
Note that photo-luminescence goes along with a loss of energy between the initial and final photon. Hence, if CO2 were to absorb a 15mikrometer photon, photo-luminescence would require the emission of a photon with a longer wavelength. But CO2 has no such longer emission lines, except for spin variants of that 15um band. But if it had, that photon could then no longer excite another CO2 molecule at 15um, because its energy would be too low.
Therefore the radiation transport model requires that the photon emitted is of the same wavelength as the photon absorbed. Otherwise there would be no transport.
Now the lifetime argument of millisecond versus nanosecond comes into play: while the excited CO2 molecule waits for re-emission of the photon, it gets bumped by the molecules around and looses that excitement into kinetic energy of the other molecules (N2, O2,…), i.e. it warms up its surroundings.
I think that the comments concerning mean time between energy exchange mechanisms is the key here. These can be conduction, convection and radiation, and as has been pointed out, conductive (collisional) events dominate in the lower atmosphere. This leads to a gravitationally induced lapse rate.
Whatever events are dominating the vetrical component of an atom’s (or molecule’s) velocity will be 9.81 m/s higher for every meter closer to the surface, giving it a higher notional temperature via the ideal gas law: T = (m*v^2) / (3*K). Think of a single atom inside a 1m high container, resting on the surface. The temperature profile shows a higher temperature at the bottom than at the top. This does not violate the laws of thermodynamics, however, becase the System (Earth plus contanit) will work to equalise the momentum exchange by accelerating the Earth’s trajectory. If an identical container is placed on the opposite side of the Earth the forces calncel and there is no acceleration. Now add all of the rest of the atoms and molecules in the attmosphere and we see a lapse rate. The conclusion is that the gravitational field gives a lower entropy system.
Is this correct?
Well, I found this just now looking for some sources I had elsewhere, and I am damn impressed with the guy’s work.
He does a good job skewering all of us, skeptic, alarmist, warmist, and dragons alike.
What is most impressive is how well he makes and supports his point with clearly explained reasoning and mathematics.
“Whatever events are dominating the vertical component of an atom’s (or molecule’s) velocity will be 9.81 m/s higher for every meter closer to the surface,”
The rate of acceleration is 9.81 m/s/s. [1 gee]
In one second something falls 4.9 meters and has velocity at this distance and at end of
1 second of 9.81 m/s.
If distance is 1 meter it’s .45 of a second and it reaches velocity of 4.43 m/s.
If vertical distance is 1000 meters it’s 14.28 seconds and velocity of 140 m/s.
A molecule at 1000 meters basically stays at 1000 meters, but without collisions
occurring every nanosecond, and so allowing it it fall, it would gain 140 m/s by time it
hit surface.
A lapse rate is 6 to 9 C difference of temperature over 1000 meter elevation- adding 140 m/s to the averaged molecules’ velocity makes a higher temperature than this reduction in temperature from lapse rate.
So temperature is cooler 1000 meters up, but molecules have more energy if include it’s potential energy due to the higher elevation.
Or dump a ton of cold air at 30 Km and it will become hot as it falls.
30,000 meters: 78 seconds to hit surface and 766.8 m/s at surface- though
it probably would not reach surface. But if it did it would be hot air.
And it would warming the atmosphere rather than cooling it.
Averaged molecular velocity in atmosphere is somewhere around 400 m/s.
Varying with local temperature and type/density of a gas molecule- lighter denser
[helium vs nitrogen] has faster averaged velocity [and according to ideal gas laws
the same kinetic energy]
Thanks gbaikie, I agree the mix up (m&s) that you pointed out.
I agree that the method gives a much higher lapse rate than that observed (I calculated 0.0313 K/m for argon, with an initial velocity of 500 m/s). However, I wondered if this was an observation of damping by convective effects in the unbounded (real) atmosphere. One thing I found interesting was that it seemed to give the same order of magnitude as results reported from experiment (Graef ?). The other thing I found interesting was the relationship between gravity and entropy.
Idle speculation, but I would be grateful for any further thoughts.
Max™ says:
March 14, 2013 at 11:42 am He seems to completely ignore the Adiabatic Lapse rate in his calculations, so do you trust them?
He is very positive in his statements, so obviously has a Lief type ego, ie he can’t possibly be wrong and absolutely everybody else is wrong..
gbaikie says:
March 14, 2013 at 12:04 pm
Wouldn’t friction with other Air Molecules heat up the Cold Mass of air very quickly when it is traveling at 140 m/s?
There would many collisions going on.
It’s a 1-layer model, and he has one example of admitting he was wrong and correcting his mistake, that puts him ahead of about half the internet, doens’t it? 😛
Plus he pointed out things I agree with and things which made me uncomfortable because I couldn’t dismiss them off hand but had to think about them more carefully, that is a good thing.
Er, “1-D” should be “1-layer”, sorry, was watching that little grep | xargs trick I shared in the other thread as it sifted through my entire hard drive and found a few references to the Shrike I didn’t know I had in there.
That comment in the FOIA post was to you, btw, tb, you can share it if you want, not sure how much file trolling you do regularly, but it’s a heck of a trick to watch in action and perfect for sifting through archives like this.
Clive Best says
top of the atmosphere. Here radiation can escape to space and balance incoming solar energy. Below this level all temperatures, including that at the surface are only determined by thermodynamics (environmental lapse rate).
I agree. Above TOA Radiation Laws, below TOA gas Laws. Above TOA no gas, below TOA lots of gas.
The altitude of the tropopause determines surface temperature,
I also agree with this. But what determines the altitude of the tropopause? I call it height of TOA.
Clive Best says
because the effective temperature of the Earth as seen from space is invariant.
What is ” the effective temperature of the Earth”. Do you mean temperature at TOA?
The temperature at TOA is quite constant, day to night, by season and from pole to equator. But how does that determine the height of TOA?
Does fig.2 in this paper by Lindzen explain what you mean?
ftp://texmex.mit.edu/pub/emanuel/PAPERS/greenhouse.pdf
Max™ says:
“… admitting he was wrong and correcting his mistake, that puts him ahead of about half the internet, doens’t it?”
Yes! :-))
But that doesn’t sanctify his work. He is beginning with the same old, same old approach for determining the impact of an atmosphere on a planets surface temperature. All he then does is to tweak and twiddle with the albedo to arrive at a different delta-T (60C versus the old 33C). And of course this is all due to a GREENHOUSE atmosphere, not just an atmosphere (indeed, adiabatic does not exist for him). And then he is building on this misguided concept for further conclusions.
I think this approach is fundamentally wrong. Yes, you can determine the amount of energy received by a planet – ignoring albedo for a moment – by thinking of a disk with the diameter of the planet to receive all the energy. But it gets wrong when you then smear this energy homogeneously over the whole planetary surface and determine the required temperature to radiate away this smeared energy.
The problem is that energy and temperature are strongly non-linearly related, namely by the well known Stefan-Boltzmann law, stating the proportionality to T^4. It would only work if the heat were redistributed infinitely fast over the whole planet. Look at the moon, where equator temps are up to +120C, and polar temps down to -120C (or less) – it does not even look like a slow distribution, let alone a really fast one. And even on earth, with its oceans and atmosphere as energy distribution system, people prefer the equator over the poles for their summer vacation for a good reason. 😉
So the very foundation for determining the global temperature from energy balance is not fulfilled – how then can any conclusion derived from it be right?
Well, I agree that there are problems with any sort of globally averaged model, I come into the debate having studied math and physics, so I’m probably just partial to seeing things taken apart in that sort of fashion.
Like I said though, I don’t agree with him on everything, but he does go over the basic physics and development behind the GHE concept with links for further exploring, which is the main reason I wanted to link it.
Clive Best says
top of the atmosphere. Here radiation can escape to space and balance incoming solar energy. Below this level all temperatures, including that at the surface are only determined by thermodynamics (environmental lapse rate).
I agree. Above TOA radiation Laws, below TOA gas Laws.
The altitude of the tropopause determines surface temperature,
I also agree with this. But what determines the altitude of the tropopause?
Clive Best says
because the effective temperature of the Earth as seen from space is invariant.
What is ” the effective temperature of the Earth”?
How does an invariant temperature determine the height of the troposphere ( HOT )?
The HOT is a measure of the amount of atmosphere. The is determined by the gravitational attraction of the planet and the tendency of gas molecules to escape gravity due to energy from the sun. HOT is determined by a balance between mass and radiation effects. From the planet and the sun.
Lapse rate and Height of Troposphere determine surface temperature.
The big factors are mass of planet, mass of atmosphere and radiation from sun.
Roger Clague says:
“I also agree with this. But what determines the altitude of the tropopause? I call it height of TOA.”
The TOA is where convection stops or perhaps “peters out” is a better phrase. As we go up in the atmosphere so more and more of the planck spectrum is free to radiate to space. Lines in the H2O band start emitting lower in the atmosphere, whereas the central 15 micron line for CO2 is way up in the stratosphere. My estimate would be that when the total radiative losses from a given level exceed maximum convective heat transfer from below the lapse rate starts to decrease and eventually reaches zero. This is the TOA.
Increasing CO2 levels is only important for the side lines of the 15 micron band. The central line actually increases radiation loss because temperature increases with height in the startopshere.The startopshere should therefore cool a little. However the side lines lie in the troposphere and will increase emission height theerby decreasing the thermal tempereature where these photons escape to space.
If you accept the line by line radiative codes this resluts in a “radiative forcing” or reduction in OLR of 3.7 W/m2 for a doubling of CO2 . However changes in H2O in the upper atmosphere can easily offset this – see post of Ken Graham.
Effective temperature of the Earth is a classic over-simplification “Wiki” concept. For a perfect black body with an albedo of 0.7 in energy balance with solar insolation the Teff = 255K. In reality it is much more complex than that because the planck spectrum measured from space is not a single temperature. The integrated radiative energy over all wavelengths however must still balance the incoming absorbed soalr energy.
CO2 does not warm surrounding molecules.. via collisions, the 010 state is an obvious radiative decay state, it’d supply over 1000C worth kinetic energy to any molecule in the assumption that the 010 state were entirely converted to translational KE. There is no possibility that any, even a slight portion, of the vibrational energy of a CO2 molecule can be translated into unidirectional KE given atoms are vibrating in opposite directions, there is no conservation of momentum.
Philr: CO2 does not warm surrounding molecules.. via collisions
How does it warm them then?
Simply put, (as I think we can all agree) backradiation in general (yes it exists) slows nighttime surface cooling to a very slight extent..as does the mere existence of an atmosphere conducting with the planetary surface.
Of course the Earth is nothing like the zero-capacity graybody often cited by the IPCC…it is a rapidly rotating “wetbody”, blanketed by oceans with immense storage capacity..they do not need much if any “backradiation” to maintain their current temperature, and feature no diurnal cycle…you might as well call them a greenhouse fluid.
Determining the effect GHGes have on the planetary temperature is difficult..it’s kind of a “pick your poison” type scenario. If remove all GHGes we’re left with a non-emitting atmosphere absorbing high levels of UV radiation. The profile may be isothermal, so we lose convective cooling of the surface..and all cloud cover. Ironically that is a better example of a true greenhouse than anything put forth by hardcore greenhoise theorists.
Of course I am only one physicist..there are many opinions in my field and they’re all very scientific. However I can survey say..there is nothing close to a “consensus” amongst us.
Philr: oceans with immense storage capacity..they do not need much if any “backradiation” to maintain their current temperature, and feature no diurnal cycle…you might as well call them a greenhouse fluid.
Something I’ve been saying for some time, considering LWIR doesn’t travel much further than its own wavelength in water before being re-absorbed. But the other major factor here must be the limitation placed on the rate of evaporation by the mass of the atmosphere creating a surface pressure of 14lbs/in^2. It’s a mass issue rather than a composition issue, would you agree?.
philr1992 says, (March 14, 2013 at 9:09 pm): “Simply put, (as I think we can all agree) backradiation in general (yes it exists) slows nighttime surface cooling to a very slight extent..as does the mere existence of an atmosphere conducting with the planetary surface.”
============================================================
This is double wrong.
First, mostly there is contact between warmer surface and colder air, that means more cooling in addition to radiative cooling.
Second. the assumption that back radiation slows down cooling means that it literally warms a body that is not cooling by itself because e.g. of an additional sort of energy, like in Willis hypothetical universe. And this leads to an impossible endless mutual warming, which renders the initial assumption wrong (https://tallbloke.wordpress.com/2013/03/10/entering-the-skydragons-lair/comment-page-1/#comment-46123).
tallbloke says, (March 14, 2013 at 8:46 pm): “Philr: CO2 does not warm surrounding molecules.. via collisions
How does it warm them then?”
This is the only way CO2 can contribute to warming. However, it’s effect would be negligible because of it’s negligible concentration.
Yes exactly, for the same reason water boils at a lower “temperature” at high altitudes…also this surface pressure slows the rate of planetary land-surface cooling as well.
A common excuse by climate scientists today is that our atmosphere is primarily composed of bi/tri atomic gases and not ideal gases”, but that is just hand waving.
The problem with physics today…too much in the way of mathematical theory that fails to accurately represent reality. This is why we’re invoking crazy hypothesis like dark matter/dark energy, black holes, Big Bang theory, etc. Big Bang theorists are the cosmological analogue to greenhouse alarmists in climatology.
Greg House,
Not true, only in the case of local thermodynamic equilibrium does your assertion hold true..like the hypothetical nuclear planet which had equilibrated prior to the instalment of the shell.
Without insolation (solar input), the Earth surface (and system) is out of equilibrium..it is continuously losing energy at a rate analogous to it’s temperature. Add in the presence of an atmosphere at a similar “temperature”, and you restrict the time the body will take to cool…the atmosphere and Earth are one body…don’t think of them as separate bodies interacting.
English is not my first language, I struggle with it at times, so I apologize if my grammar is off.
“A C Osborn says:
March 14, 2013 at 12:52 pm
gbaikie says:
March 14, 2013 at 12:04 pm
Wouldn’t friction with other Air Molecules heat up the Cold Mass of air very quickly when it is traveling at 140 m/s?
There would many collisions going on.”
Air molecules don’t have friction with gas molecules.
Air molecules can be compressed and so cause heat. Impactor from space, are going so fast
that air doesn’t have enough time to move out of the way. It’s the heat and high pressure which
causes them to explode
With the cold mass of air, it could fall like a brick until reached higher density air, and it would compress this denser air to some extent thereby generating some heat.
Unless air is very cold [say around 20 K] it’s going spread out quite a bit as it falls.
I think it would be interesting to watch [with sensors that could see it].
It’s kind misnomer to call it compression. The cold air would pass thru the less dense air, and as approached the troposphere [and gaining velocity] it should accumulate atmospheric gases causing the atmospheric gas to head same direction- so have pressure ahead of it and more of a vacuum behind it. One might have a sonic boom and other loud noises.
Clive;
“startopshere” sounds interesting. Where is it to be found? ;p 😉
Brian,
The “startopshere” is a zone of instability induced by tropical solar insolation, a couple of beers and a stupid iPad.
Back in the cold austere UK now, wondering just when all that extra CO2 is going to start kicking in ?
clivebest says:
March 13, 2013 at 9:43 am
According to this argument doubliing CO2 would double the lapse rate ! It is simply wrong.
=========
Correct, except that the lapse rate is limited by gravity. Air cannot fall faster than 9.8 m/s, which prevents the lapse rate from increasing beyond this point.
However, without GHG there would be no lapse rate, which would eliminate convection and warm the surface – exactly the same way a real greenhouse warms the surface – by reducing convection.
Thus, increasing GHG cannot warm the surface, because it makes convection more likely, up until the point at which gravity prevents further increase. At which point, adding more GHG has no effect.
Clearly there is a problem in Wikipedia using the IPCC as a reference because the IPCC itself acknowledges it does no science. Supposedly the IPCC simply publishes the scientific findings, but as has been shown much of what the IPCC publishes is in fact not even peer reviewed
The gold standard in science is peer reviewed, replicated by a skeptical examiner and does not conflict with observation. Very little of what passes for science today meets this qualification – in any field that is supported by government funding.
The biggest problem for climate science and the GHG theory is that virtually every prediction based on the theory has been contradicted by observations over the past 15 years. In every other branch of science this would have served as a massive red flag that the theory was wrong and a rethink was required.
Instead, what has happened in climate science is that the theory has been adjusted to predict warming and cooling, increased and decreased snowfall, increased and decreased rainfall. In other words, the theory predicts that any change is due to GHG. And if there is no change, that is due to natural variability.
As a consequence, the GHG has zero scientific value because it is worthless for prediction. You cannot use the theory to make any meaningful prediction about the direction in which the change will occur, or even if there will be a change.
All the GHG theory really tells you is that you cannot reliably predict the future. And that the GHG theory is very reliable in this prediction. GHG theory predicts there will be increased change due to humans, or not, depending on natural variability. Of that we can be sure.
In other words, change is due to humans, and lack of change is due to natural variability. When things stay the same, GHG theory predicts that it is the natural variability in climate that is preventing the climate from changing.
ferdberple says:
…. Air cannot fall faster than 9.8 m/s, which prevents the lapse rate from increasing beyond this point.
Oh, please. That number 9.8 probably refers to the gravity constant, which however is 9.8 m/s² (second squared!). This is an acceleration and NOT a velocity.
And 9.8m/s (now really as a speed) is only 35km/h, or 19kn, which is a wind speed good for a Sunday afternoon family sailing on the ocean, even with a spinnaker up! A hurricane becomes category 5 at almost 10x that speed.
ulrich steiner, way up thread you were speaking of Prof Heinz Hug’s work and mentioned the 20.2 m²/mol molar extinction coefficient specifically for carbon dioxide. But my interest due to a quite accidental discovery crossing to Venus is in the molar extinction coefficient of air itself. Have you ever come across whether that measurement has been performed on air (all components at normal concentration)? I’ve looked but can find nothing.
Also I did immediately notice you being careful to mention both sides of the physics, such as if it absorbs less so it can hit the surface it also emits less, and such. Bravo. I rarely here anyone saying both sides together and physics is thick with such symmetries. It’s hard to get an upper hand, either way, on nature. I am thoroughly enjoying yours and philr1992’s comments. Thanks to both of you for taking the time (hope you both continue! ;))
@ philr
When you say “CO2 does not warm surrounding molecules.. via collisions, the 010 state is an obvious radiative decay state, it’d supply over 1000C worth kinetic energy to any molecule in the assumption that the 010 state were entirely converted to translational KE.”
Are you sure you are not looking at the symmetric stretch of co2 which is in the near IR? At 2.7 μm I believe (without looking it up). I would agree with you there about the lack of thermalization due to symmetry but I could swear I read that the 15 μm is the asymmetric bend mode and it does have a temporary dipole moment (due to collisions). If I’m wrong in places please say more, this information is hard to come by and many times is conflicting.
wayne says:
“… interest … in the molar extinction coefficient of air itself. Have you ever come across whether that measurement has been performed on air (all components at normal concentration)? ”
I guess you are aware of the fact that the extinction for gases is wavelength dependent and specific for each type of molecule? These wiki graphs may give an impression of the molecules’ contribution http://upload.wikimedia.org/wikipedia/commons/4/4c/Solar_Spectrum.png and http://en.wikipedia.org/wiki/File:Atmosfaerisk_spredning.gif
With the exception of 1 O2 line (I believe there are 2 more small O2 lines in the visible, not marked in the graphs) there are only 3-atomic molecules involved in the region from visible via NIR to FIR (Near/Far Infrared), because those low-energy vibration modes need the three atoms. I am not sure in which mode O2 is resonating in visible.
Or is your question about a fictitious extinction of of the whole spectrum through the whole atmosphere, including Rayleigh scattering, dust, aerosols and just asking about how much gets lost overall?
Interesting exercise, let’s try it.
The solar constant outside the atmosphere is 1366W/m2. On the ground, on a good day, and perpendicular to the sun we can get 1000W/m2.
extinction coefficient:…. x (to be determined)
height of atmosphere:… 10km (i.e.troposphere only)
gas conc ground:……….. ideal gas @22.4l/mol =>44.6mol/m³
gas conc atm.avg:……… ~20mol/m³ (at 10km, p=260mbar, roughly linear up to there)
Transmission:……………. T = 1000/1366 = 0.73 = 10^-A ==> A=-log(0.73)=0.137
A= x * 20 mol/m³ * 10000 m = 0.137
we get x = 0.00000069 m²/mol
So, for whatever it is worth, this approach gets us a “molar extinction” coefficient for the whole incoming radiation in the whole atmosphere of 6.9*10⁻⁷ m²/mol. (compared with CO2 at ~15um of 20.2 m²/mol)
That is pretty transparent, as we all know.
JohnG says: March 13, 2013 at 10:37 am
“Perhaps this article will help:
http://greenhouse.geologist-1011.net/
Abstract: ……”The general idea as expressed in contemporary literature, though seemingly chaotic in its diversity of emphasis, shows little change since its revision by Svante Arrhenius in 1896, and subsequent refutation by Robert Wood in 1909.”…….”
Let’s take it from there for the “refutation”.
It then goes on to say that….”Moreover, the temperature of the earth’s surface and the temperature in a greenhouse are adequately explained by elementary physics. Consequently, the dubious explanation presented by the “Greenhouse Effect” hypothesis is an unnecessary complication. Furthermore, this hypothesis has neither direct experimental confirmation nor direct empirical evidence of a material nature.”.
However, ‘is’ this explained by “elementary physics”? Is it “an unnecessary complication”? Has it “neither direct experimental confirmation nor direct empirical evidence of a material nature”?
It would be nice to ‘investigate’ this falsification, if only to understand the detail better.
FWIW, I envisage a “Greenhouse” in a ‘desert location’ as providing a ‘lesser’ surface temperature increase than a “Greenhouse” in a ‘temperate location’. Why? When latitudinal ‘surface insolation values’ are taken into consideration, the ‘desert location’ inhibits solely ‘convection’, but the ‘temperate location’ inhibits both ‘convection’ and the evolution of the ‘latent heat’ that buffers surface temperature.
When the IPCC seems to ‘shun’ detail on the role played by H2O, both in the atmosphere ‘and’ at the atmosphere/surface interface, there can only be ‘room for improvement’ of this, scant, detail. 🙂
Best regards, Ray.
PS. Sorry for the late link to JohnG, but you guys seem to be ‘out of puff’ now (mostly). 🙂
Ray: Maybe this article will help:
tallbloke says: March 17, 2013 at 11:40 pm
“Ray: Maybe this article will help:
https://tallbloke.wordpress.com/2012/03/21/roy-clark-where-it-all-went-wrong-with-climate-science/”
Not really TB. For example:
“Latent heat and wind driven evaporation are also fundamental in setting the surface temperature, especially over the oceans. The heat capacity of the ground is somewhere around 1.5 MJ.m-3 and that of water is ~4 MJ.m-3.”.
What’s the difference between “~” and “somewhere around” TB? Not much, I’ll wager, but the definitions do ‘differ’ for the stated ‘differentiated scenarios’. This ‘hides’ the ‘insolation value’ for OLR!
IMHO, the 80W/m^2 of ‘insolation’ that relates to ‘latent heat’ in the Trenberth et al ‘cartoon’ not only ‘subdues’ surface temperature, it also ‘elevates’ tropospheric temperature as the ‘latent heat’ is released and, ‘may’, be seen/observed as ‘back radiation’!
Best regards, Ray.
ulrich, yes, I do realize all that you questioned. My question was more a whole-sky whole-spectrum type of question but no problem. I do believe you gave me exactly what I needed, how to calculate using this new unit of molar extinction (to me anyway). I have never dealt with such a factor of m²/mol to date (somewhat new to the branch of atmospheric physics) so I now see how it relates. Your clear-sky example was great and I will modify it as needed.
Thank you so much, much of these simple, but branch-specific things as you just calculated, seem to be nowhere easily found or accessed on the web. You don’t realize how great your answer was. 😉
The warming is caused by IR, not by molecules that are in a higher level of activity. Because contact is required to be aware of warm molecules, and because we are in contact with so few molecules relative to the number of molecules available, what we experience as warmth is the IR that is in transit between molecules. And because there are more such molecules (capable of and re-radiating IR) we are aware of and can measure more heat. And if that were all there was to the badly named GHG issue the planet would grow warmer as the percentage of GHGs grows. But that is not even close to all that happens and it is that everything else that the alarmists are ignoring but which is responsible for the nearly 2 decades of heating pause.
‘Nuther point. Any IR that is radiated at angles that are above the horizon are in a favorable position to achieve greater altitude which obviously decreases the horizon to horizon included angle at the next stop. This ties in with extinction range of IR. At higher altitudes favorable exposure to space and longer extinction ranges work to get IR out of the Earth system. This higher, ever higher tendency is a critical factor in balancing the energy budget.
Last point. It is perfectly possible for a cooler object to illuminate an adjacent warmer object. In fact it is impossible for it to not illuminate any object, hot or cold, because the radiating molecule has no prior knowledge of the presence or absence of objects around it. It simply radiates and that radiation strikes what ever is in the way and that energized that object. No objects in nature have Star Trek energy shields and so they behave normally in the presence of incoming radiation from a cooler object. We can infer this from the basic fact that a warmer object will cast a shadow thrown off by a cooler object.
How can they not?
dp: “How can they not?”
By the local radiative e/m field about these molecules at the same frequencies which they can emit. Do you think the molecules are immune to such e/m fields within they are immersed? Feynman used the words that they “feel out the space about” though that does give you the incorrect impression of action at a distance by I do understand what he was saying. The local e/m field dictates how radiation emits from the molecules.
You would be correct in the case of lone molecules in the void of space far removed from other matter.
*dp says: March 18, 2013 at 3:35 pm
I concur. 🙂
*wayne says: March 18, 2013 at 4:48 pm
“You would be correct in the case of lone molecules in the void of space far removed from other matter.”
Not strictly true. ‘Tuned’ LASERs are used to further refrigerate a ‘cold gas’ to temperatures very close to absolute zero in an experiment to observe the effects of a ‘Bose-Einstein Condensate’ (BEC).
BEC:
http://en.wikipedia.org/wiki/Bose%E2%80%93Einstein_condensate
Laser cooling:
http://en.wikipedia.org/wiki/Laser_cooling
The ‘microscopic world’ of quantum mechanics actually seems to agree with the ‘macroscopic world’ on this point.
Anyone fancy setting up an experiment where an object at a ‘stable temperature’ is irradiated with IR at a ‘Planck level’ fractionally below the ‘Planck level temperature’ of the object?
This is all about the ‘frequency’ (wave length) of an electromagnetic emission against the ‘reactance’ of the ‘mass’. 🙂
Best regards, Ray.
Sure Ray, but without bringing in qm effects on the macroscopic scale, I think what I said it correctly. Dp was wonder why that would not be so. Prof. Susskind states (I’ve gone back to virtual school,three more lectures today) it this way, my translation, the radiative density right at any surface in a black body cavity is zero at any surface when all are at equal temperatures. Don’t know about you, but I didn’t quite realize that, about the radiative density, took a while for that to sink in, and he show the equations backing it. That seems also why he speaks of photons bouncing off surfaces at equal temperature, not absorbing and emitting, but that is what I have always thought since college. Want some links to a few great statistical mechanics lectures on black bodies, Stefan-Boltzmann, radiation, etc. by a top physicist? As far as I can tell, it is great anti-AGW medicine, I was surprised, no left leaning tint, in fact no tint at all. Who knows, maybe Susskind is a bit of a skeptical though I think he doesn’t lean either way, just straight physics. In fact, through those lectures, I’m beginning to see just where AGW does fail and finally it is provable and brings Miskolczi right back into focus. Curious? It’ll take some hours of listening.
suricat says: March 19, 2013 at 12:52 am
“This is all about the ‘frequency’ (wave length) of an electromagnetic emission against the ‘reactance’ of the ‘mass’.”
I’ll add to that. A ‘phase lead’ ‘cools’ (detracts inertia from the mass), whilst a ‘phase lag’ ‘heats’ (increases inertia to the mass).
Think of a child’s ‘swing’. 🙂
The ‘timing’ to a ‘1/4’, ‘1/2’ or ‘full waveform’ is critical!
Best regards, Ray.
wayne says: March 19, 2013 at 2:13 am
“Sure Ray, but without bringing in qm effects on the macroscopic scale, I think what I said it correctly”
Yes, but there are ‘other’ avenues to follow.
“Dp was wonder why that would not be so. Prof. Susskind states (I’ve gone back to virtual school,three more lectures today) it this way, my translation, ‘the radiative density right at any surface in a black body cavity is zero at any surface when all are at equal temperatures.'” (sorry, but I can’t replicate italics here so I’ve enclosed italics within single quotes)
My post wasn’t about ‘black body’ interpretation. It was about the interpretation of a ‘real’ scenario.
Best regards, Ray.
Just chiming in to add that Susskind is one of the rather small group that is both capable of actively discussing theoretical physics on an even playing field with Hawking, as well as being a member of the group that wound up showing he was wrong about black holes and information loss.
I’m not completely sold on stringy models, but it has produced many useful spinoffs, like the http://en.wikipedia.org/wiki/AdS/CFT_correspondence, as well as Holography with it’s contributions to Information theory. Susskind worked with Bekenstein and Penrose as well, and the whole crowd has contributed hugely to the understanding of black holes and astrophysics in general.
Max™ says: March 19, 2013 at 3:42 am
The ‘quantum’ route wasn’t one that I wanted to take and that’s why I hinted at a child’s ‘swing’, but molecules possess mass and electrical charge, and move within an electromagnetic field. Thus, the EM field and the mass of the charged particles are mutually connected (a charged particle on the move produces a magnetic field of magnitude comparable to its charge, velocity and inertial mass).
However, the phrase “the radiative density right at any surface in a black body cavity is zero at any surface when all are at equal temperatures.” doesn’t make sense to me in English (BB or not). There must be something lost in translation because, surely, this must be a statement for the conditions relating to ‘zero energy transport’ and ‘not’ ‘radiative density’? I can only think that within a ‘uniform radiative density’ there can be ‘no radiative energy transport’.
WRT ‘atmospheric conduction’ (molecules bumping together), they don’t. The electrons that surround each atom and the valency electrons that hold the the atoms in the shape of a molecule all present a -ive static surface charge that prevents a ‘full on’ contact collision between molecules. There are ‘electrostatic’ and ‘electromagnetic’ forces involved that prevent a ‘contact type collision’ without the intervention of ‘lightning’, ‘thermosphere migration’, or an inclusion within a Slack, or CERN experiment (HE physics). Though photosynthesis rends CO2 and H2O quite well.
I’d rather discuss the effect of ‘back radiation’ and what ‘wavelength’ (frequency [the ‘inverse’ of wavelength]) has to do with energy transfer between EM radiation and a mass object. In particular, the effect due to ‘resonance’. I’ve found that ‘harmonics’ are an ‘important’ feature in a better understanding of nature. 🙂
Best regards, Ray.
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