Guest post by Bob Fernley-Jones by Bob Fernley-Jones AKA Bob_FJ
CAUTION: This is written in Anglo-Oz English.
Here is the diagram as extracted from their 2009 paper, it being an update of that in the IPCC report of 2007 (& also 2001):
The unusual aspect of this diagram is that instead of directly showing radiative Heat Transfer from the surface, it gives their depiction of the greenhouse effect in terms of radiation flux or Electro-Magnetic Radiation, (AKA; EMR and a number of other descriptions of conflict between applied scientists and physicists). EMR is a form of energy that is sometimes confused with HEAT. It will be explained later, that the 396 W/m^2 surface radiation depicted above has very different behaviour to HEAT. Furthermore, temperature change in matter can only take place when there is a HEAT transfer, regardless of how much EMR is whizzing around in the atmosphere.
A more popular schematic from various divisions around NASA and Wikipedia etc, is next, and it avoids the issue above:
- Figure 2 NASA
Returning to the Trenberth et al paper, (link is in line 1 above), they give that the 396 W/m2 of EMR emitted from the surface in Fig.1 is calculated primarily by using the Stefan–Boltzmann law, and global year average conditions. Putting aside a few lesser but rather significant issues therein, it is useful to know that:
1) The Stefan-Boltzmann law (S-B) describes the total emission from a flat surface that is equally radiated in all directions, (is isotropic/hemispherical). Stefan found this via experimental measurement, and later his student Boltzmann derived it mathematically.
2) The validity of equally distributed hemispherical EMR is demonstrated quite well by observing the Sun. (with eye protection). It appears to be a flat disc of uniform brightness, but of course it is a sphere, and at its outer edge, the radiation towards Earth is tangential from its apparent surface, not vertical. It is not a perfect demonstration because of a phenomenon called limb darkening, due to the Sun not having a definable surface, but actually plasma with opacity effects. However, it is generally not apparent to the eye and the normally observed (shielded) eyeball observation is arguably adequate for purpose here.
3) Whilst reportedly the original Stefan lab test was for a small flat body radiating into a hemisphere, its conclusions can be extended to larger areas by simple addition of many small flat bodies of collectively flat configuration, because of the ability of EMR waves to pass through each other. This can be demonstrated by car driving at night, when approaching headlights do not change in brightness as a consequence of your own headlights opposing them. (not to be confused with any dazzling effects and fringe illumination)
4) My sketch below demonstrates how radiation is at its greatest concentration in the lateral directions. It applies to both the initial S-B hemispherical surface radiation and to subsequent spherical radiation from the atmosphere itself.
5) Expanding on the text in Figure 3: Air temperature decreases with altitude, (with lapse rate), but if we take any thin layer of air over a small region, and time interval, and with little turbulence, the temperature in the layer can be treated as constant. Yet, the most concentrated radiation within the layer is horizontal in all directions, but with a net heat transfer of zero. Where the radiation is not perfectly horizontal, adjacent layers will provide interception of it.
A more concise way of looking at it is with vectors, which put simply is a mathematical method for analysing parameters that 
possess directional information. Figure 4, takes a random ray of EMR (C) at a modestly shallow angle, and analyses its vertical and horizontal vector components. The length of each vector is proportional to the power of the ray, in that direction, such that A + B = C. Of course this figure is only in 2D, and there are countless multi-directional rays in 3D, with the majority approaching the horizontal, through 360 planar degrees, where the vertical components also approach zero.
6) Trenberth’s figure 1 gives that 65% of the HEAT loss from the surface is via thermals and evapo-transpiration. What is not elaborated is that as a consequence of this upward HEAT transfer, additional infrared radiation takes place in the air column by virtue of it being warmed. This initially starts as spherical emission and absorption, but as the air progressively thins upwards, absorption slows, and that radiation ultimately escapes directly to space. Thus, the infrared radiation observable from space has complex sources from various altitudes, but has no labels to say where it came from, making some of the attributions “difficult”.
DISCUSSION; So what to make of this?
The initial isotropic S-B surface emission, (Trenberth’s global 396 W/m2), would largely be absorbed by the greenhouse gases instantaneously near the surface. (ignoring some escaping directly to space through the so-called “atmospheric window”). However, a large proportion of the initial S-B 396 surface emission would be continuously lateral, at the Trenberth imposed constant conditions, without any heat transfer, and its horizontal vectors CANNOT be part of the alleged 396 vertical flux, because they are outside of the vertical field of view.
After the initial atmospheric absorptions, the S-B law, which applied initially to the surface, no longer applies to the air above. (although some clouds are sometimes considered to be not far-off from a black body). Most of the air’s initial absorption/emission is close to the surface, but the vertical distribution range is large, because of considerable variation in the photon free path lengths. These vary with many factors, a big one being the regional and more powerful GHG water vapour level range which varies globally between around ~0 to ~4%. (compared with CO2 at a somewhat constant ~0.04%). The total complexities in attempting to model/calculate what may be happening are huge and beyond the scope of this here, but the point is that every layer of air at ascending altitudes continuously possesses a great deal of lateral radiation that is partly driven by the S-B hemispherical 396, but cannot therefore be part of the vertical 396 claimed in Figure 1.
CONCLUSIONS:
The vertical radiative flux portrayed by Trenberth et al of 396 W/m^2 ascending from the surface to a high cloud level is not supported by first principle considerations. The S-B 396 W/m^2 is by definition isotropic as also is its ascending progeny, with always prevailing horizontal vector components that are not in the field of view of the vertical. The remaining vertical components of EMR from that source are thus less than 396 W/m^2.
It is apparent that HEAT loss from the surface via convective/evaporative processes must add to the real vertical EMR loss from the surface, and as observed from space. It may be that there is a resultant of similar order to 396 W/m^2, but that is NOT the S-B radiative process described by Trenberth.
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ADDENDUM FOR AFICIONADOS
I Seek your advice
In figure 5 below, note that the NIMBUS 4 satellite data on the left must be for ALL sources of radiation as seen from space, in this case, at some point over the tropical Pacific. The total emissions, amount to the integrated area under the curve, which unfortunately is not given. However, for comparison purposes, a MODTRAN calculator, looking down from 100 Km gives some interesting information for the figure, which is further elaborated in the tables below. Unfortunately the calculator does not give global data or average cloud/sky conditions, so we have apples and pears to compare, not only with Nimbus, but also with Trenberth. However, they all seem to be of somewhat similar order, and see the additional tabulations.
| Compare MODTRAN & “Trenberth”, looking down from 2 altitudes, plus Surface Temperature | ||||
| Location | Kelvin | 10 metres | 100 Km. | (Centigrade) |
| Tropical Atmosphere | 300K | 419 W/m^2 | 288 W/m^2 | (27C) |
| Mid-latitude Summer | 294K | 391 W/m^2 | 280 W/m^2 | (21C) |
| Mid-latitude Winter | 272K | 291 W/m^2 | 228 W/m^2 | (-1C) |
| Sub-Arctic Winter | 257K | 235 W/m^2 | 196 W/m^2 | (-16C) |
| Trenberth Global | 288K ? | 396 W/m^2 | 239 W/m^2 | (15C ?) |
| Compare MODTRAN & “Trenberth”, looking UP from 4 altitudes: W/m^2 | ||||
| Location | From 10 m | From 2 Km | From 4Km | From 6Km |
| Tropical Atmosphere | 348 | 252 | 181 | 125 |
| Mid-latitude Summer | 310 | 232 | 168 | 118 |
| Mid-latitude Winter | 206 | 161 | 115 | 75 |
| Sub-Arctic Winter | 162 | 132 | 94 | 58 |
| Trenberth Global | 333 Shown as coming from high cloud area (= BS according to MODTRAN) | |||
Bob,
“Oh BTW, the atmospheric widow is a separate issue, where I’ve repeatedly said like; ignoring stuff escaping directly to space.”
Do you agree that not all of which passes directly from the surface into space is from that emitted perpendicular?
Bob says “If you are describing an S-B calculation … ”
I’m not describing any calculation; I am describing what you would measure with an actual IR detector (eg a pyrgeometer or simple IR thermometer). I would be willing to make a friendly wager that the spectrum and/or total IR power observed when the detector is 100 meters over a uniform, level surface would be indistinguishable from the spectrum 10 m above the surface or 1 m above the surface. (The only differences would be from 1) the *slight* affect of curvature of the earth and 2) a *slight* drop in temperature of the GHGs as you go up (~ 0.6 K for typical lapse) ).
And even with a S-B calculation, the IR intensity would not show any (noticeable) drop at 100 m. The surface will STILL cover 2 pi steradians of solid angle, and the incoming radiation will still be the same.
For example, we could buy one of these cheap IR thermometers http://www.thermoworks.com/products/ir/ir_mini.html#Specifications. It has a relatively wide field of view. I would argue that if the ground is a uniform temperature & emissivity, the thermometer will read the same value, regardless of how high you are above the ground (until the lapse rate and/or curve of the earth become important).
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At this point, I think it is time to call it good for this discussion. I don’t think I am getting my point across, and without actually talking and drawing pictures on sheets of paper in front of us I don’t think we are going to make further progress.
I wish you well in your quest for understanding.
Tim Folkerts @ur momisugly November 26, at 7:23 am to Jose
Tim, have you considered the possibility that above the clouds, not only is water mostly irrelevant, but so too is CO2? I think this is so, because not only is the air colder, resulting in lengthening of EMR wavelengths, but also the air is getting thinner, resulting in greatly increased photon free path lengths. It’s all over up there denken sie?
AND, concerning atmospheric water, it is also interesting to follow the war between that elitist alarmist atmospheric physicist Andrew Dessler, (with whom I’ve had some interesting intercourse a few years ago), and Roy Spencer et al. Back in January 2009 Dessler wrote this great wisdom at Grist; (my bold):
Negative climate feedback is as real as the Easter Bunny. http://www.grist.org/article/Negative-climate-feedback-is-as-real-as-the-Easter-Bunny
That was before some more recent research. Well Tim, don’t be timorous; how about you research the literature on this, and not just water vapour, but clouds
No mention of the much greater evapotranspiration cooling and stuff according to Trenberth of course.
Jose_X, the physics I am invoking is the concentration (partial pressure of CO2, Pc), distance mean free path of photon beam, L) relationship (PcL). Reducing atmospheric CO2 to 100ppm would not rduce the number of first generation photons absorbed in the relevant bands, but the distance over which they were absorbed would increase. Conversely increasing CO2 beyond 380ppm would reduce the absorption to extinction distance but would not absorb any more first generation photons, The subsequent retention time of these photons as they are re-emitted may be slightjy altered but not to affect the overall heat balance.
Bob, Tim, Jose, might I reenter this conversation for a moment, but first, I have come across a great link you might find helpful, pure correct physics and I finally found it here on the web, halleluiah!
http://astronomyonline.org/Science/RadioAstronomy.asp
Nothing like good ‘ol radio astronomy text which deal with radiation in these thermal/microwave/radio frequencies to give us a reference we can refer to ( had a bit of a problem physically getting my physics books onto the web, but this will now do ☺) and talk apples to apples.
See Tim and Jose, I agree with what that short book explains basically in toto. It’s a little skimpy in details but didn’t detect any scientific flaws. That is the science I have learned over the decades pre-AGW “climate science”. All matter radiates, EVEN GASES in a blackbody manner. All electrons ALWAYS radiate when externally accelerated, EVEN BUMPING O2 and N2, across the entire spectrum per T. Radio astronomers know this well. Our entire atmosphere radiates. Yes, GHG’s have strong absorption/emission lines and continuum but look at any spectrum of the atmosphere and this BB radiation underlies all of them. I know, would be called blasphemy to many today. The actual science has been re-written for a cause.
Bob, after reading all comments since I left, I have to bring up one point where you seem to keep stopping one step short of saying what is happening horizontally in thermal resonance. You end you statement with extinction. But that is just normal energy transfer and Tim is right then taking your one-step short statement and saying that is warming, it is. Extinction warms the destination and cools the source. That one step short of my A to B and B to A description above which is a null, or, oh, what word… resonance, or two-directional transfer with no NET transfer so no change in the temperature at either point. Do you see that subtle difference there? The identical and opposite side has to be included for cancellation to occur, and this happens even if you separate vectors across axes and are addressing those components.
All of that I said in comments above was an attempt to explain this, it is merely another way to view the energy transfers in contrast to Trenberth’s graphic. He has 396-333=63 of which 40 shuttles directly to space leaving 23 Wm-2. A pure geometrical 3d view gives you 396/6=66 of which 40 would also go directly to space leaving 26 Wm-2. The 4 horizontal components always completely cancel in our rather thick troposphere in the infrared/microwave. One question I have not answered yet for myself is what then exactly causes this 3 Wm-2 difference between those two views, one 63 and the other 66. In a geometric view, is that concerning GHG’s absorption or purely the atmosphere’s mass attenuation?
To me the geometric view is much cleaner, for that very aspect mention way back in these comments. It so very simply explains Mars atmosphere completely and the radiation transfers within. Nearly zero is absorbed so that any direction radiation goes it is to space, on all five axes. Mars temperature IS its BB temperature. Both 210K.
It also seems to explain Venus’s also. At the surface the radiative density is ~17000 W/m2 (740K), not 390 as here on earth and the DWLR is, let’s guess, about 16985 W/m2 at the surface with a NET upward of 15 W/m2. But 65 W/m2 is measured at TOA (compared to ~239 here) so means some 45 W/m2 in this example is absorbed by Venus’s atmosphere (and those are very rough guesses for example only). At the surface, in a near liquid co2 state, all 6 axis direction axes are in resonance but upward z+ still has a very tiny tendency (that’s why I brought in the ‘mass attenuation coefficient’, there are 94 equivalent earth atmospheres for the surface radiation to pass through when exiting, 17000/6 is attenuated down to a mere 15 Wm-2). Just skim off the gist of that explanation.
That is the good I found shining from your approach laid out by your post. Much more realistic on first principles, and getting closer to the approach that I think that should be applied to further analyze our atmosphere’s radiation.
Still have a hunch that 3 W/m2 difference is from our atmosphere’s shear mass that surface radiation must pass through, therefore the non-window radiation is attenuated, and not having anything to do with GHG’s absorption, water vapor or co2.
Of course, this view could also be very wrong, but I don’t seem to see it, but tear away all.
Tim and Jose, I know that is a very unconventional way to view the atmosphere’s radiation but that is what science is, questioning every aspect, from every direction possible. That is always where the hidden answers lie (though they sure don’t happen very often!).
Robert S, if first generation photons get absorbed closer to the ground, this has a cascading effect. Second generation would also get absorbed closer. The effect is that photon energy that would otherwise have left the atmosphere will still be in transit. Up and down the atmosphere, there will be a larger amount of total energy from earlier generations (going back to negative infinity). This implies a higher average kinetic energy per molecule, aka, higher temperature.
Where you say “negligible”, I say, yeah if a few degrees hotter is negligible. In any case, either of us would have to provide computations to give a more definite answer in the context of our current atmosphere. However, without performing more calculations, I certainly find it reasonable that there would be a rise of say 1 degree C (or something near that) solely on account of this higher CO2 doubling. In any case, we seem to both agree that higher CO2 concentration promotes higher temperatures (although you claim “negligible”), at least if we ignore more complex phenomenon (clouds and what have you), which we’d have to analyze additionally.
@wayne
>> All matter radiates, EVEN GASES in a blackbody manner.
For easier reference and comparisons, could you point out where on that page this is stated or implied.
>> All electrons ALWAYS radiate when externally accelerated, EVEN BUMPING O2 and N2, across the entire spectrum per T.
Then an electron moving around a nucleus should be radiating nonstop, right, even if the atom is alone in space, right? Wouldn’t then a static isolated neutral atom seemingly radiate an infinite amount of energy in the limit? Or what do you mean by “externally accelerated”?
And remember that we are generally talking about neutral atoms. What exactly is happening there with that positive and negative charges so close to each other and “moving” around (aka “accelerating”) so much?
The link you gave includes this:
“Molecules, as well as atoms, in their gas phase also absorb characteristic narrow frequency bands of radiation passed through them. In the microwave and long wavelength infrared portions of the spectrum, these lines are due to quantized rotational motion of the molecule. The precise frequencies of these absorption lines can be used to determine molecular species. This method is valuable for detecting molecules in our atmosphere, in the atmospheres of other planets, and in the interstellar medium. Organic molecules (that is, those containing carbon) have been detected in space in great abundance using molecular spectroscopy. Molecular spectroscopy has become an extremely important area of investigation in radio astronomy.”
So, if everything radiated as blackbody, we would not be able to identify anything by its spectra (that concept would not even exist) because the blackbody frequency distributions would vary only with temperature no matter the material.
This obviously is not what that article is saying. It specifically is saying that gases can be identified by unique fingerprints.
Gas molecules bumping require momentum and energy to be conserved as we observe with large bodies (or so go many theories); however, I think quantum mechanics probability wave functions stipulate that we might also get radiation (or not) and this would affect the final energies and momentums of the 2 molecules (and possible photon(s)). At these low scales, whether a photon is absorbed or released and when is a probabilistic phenomenon, which in theory would be described by the molecule’s QM wavefunction. In aggregates of many atoms, such probabilities may lead to a “smooth” range of observed values or at a “smooth” range of times so that we may approximately say that acceleration of charged particles always leads to “EMR”, but, at an individual level, any given photon may not release any photons.
People who work with antennas (engineers and scientists) likely use classical theories. The antennas are massive items loaded with molecules. When you have a huge number of such molecules interacting with each other closely (as in a solid), you get “thick” statistics and so can end up with blackbody. From a QM view, you have such complex wave functions that essentially have as potential measurable energies a continuum of energy values. With gases, you probably don’t get ready access to anything resembling a continuum of values. [I am not sure (don’t remember). We obviously have both kinetic energy of the molecule’s motion and the electron energy levels to trade off, but I think experiments suggest more quantized behavior when you have photon and molecule interacting vs say two molecules’ nucleus coming into the vicinity of each other and the resultant changes in kinetic energies. I need to get back to the books at some point… and check this out: http://www.colorado.edu/physics/2000/lasers/lasers2.html ]
>> A pure geometrical 3d view gives you 396/6=66
What is so fundamental about “6”? Might you be favoring “6” specifically because you noticed the relationship above? Why isn’t “top” defined by the “top hemisphere” (aka 1/2)? or why not top be the top 1% of surface area only? Why should “6” somehow define what is or isn’t “lateral”?
There really is no reason for “6”. We have a continuum, and approximating it as 6 is an arbitrary approximation.
>> The 4 horizontal components always completely cancel
No cancellation, I don’t think (ie, in the quantum wave function interference sense).
What we have is that for every lateral photon deviating to the side at some point, we have others from nearby (or faraway) points that also release lateral photons towards the original point. A sensor above any area gets photons from directly below and from the side. So while it doesn’t capture the photons originating below and moving sideways, it compensates (on average) from photons originating far away and moving laterally to the sensor.
If we hypothetically cover the whole earth in sensors quickly at a point in time, we’d likely observe that all “lateral” photons from below, would have to hit some sensor or other. Every photon would hit some sensor and the average would be the same as if all photons went straight up — we could not tell either way as we’d have no way to identify the origin.. the totals would add up just the same.
wayne, I just found this link http://www.cv.nrao.edu/course/astr534/LarmorRad.html
Skip to the bottom few paragraphs (right after they finish deriving “Larmor’s equation”).
At first, it appears to say what you were saying:
“It states that any charged particle radiates when accelerated and that the total radiated power is proportional to the square of the acceleration. Since the greatest astrophysical accelerations are usually electromagnetic, the acceleration is usually proportional to the charge/mass ratio of the particle. Thus radiation from electrons is typically 4106 stronger than radiation from protons, which are 2103 times more massive.”
Notice that it even uses the example of a single electron or proton.
However, as we read further we get the disclaimers:
1 — “Beware that Larmor’s formula is nonrelativistic”
and then the one relevant here:
2 — “Also, Larmor’s formula does not incorporate the constraints of quantum mechanics, so it should be applied with great caution to microscopic systems such as atoms. For example, Larmor’s equation incorrectly predicts that the electron in a hydrogen atom will quickly radiate away all of its kinetic energy and fall into the nucleus.”
So my point is that classical mechanics uses a language that appears to imply it applies to subatomic particles, atoms, and small molecules by themselves, but it only does so as a vehicle to help explain how to use the formulas and theories on macroscopic systems. [Hypothetical example: “If we have 1 billion atoms, take this equation that applies to any number of atoms and put in a value of 1 billion for n.” However, in reality, we likely could not apply this formula to a small number n of atoms.]
@ur momisugly Jose_X
Larmor’s formula? Sounds interesting, I’ll look at it later.
Whoa.. I’m not here to teach you or argue. All of the objections you site happen to also be answered in the book of which I gave you the link. And yes Jose, I was not speaking of electrons falling into the nucleus but if you had any insight in physics at all you would have known that yourself, I even specified external and you still can;t seem to grasp it.
Spend an hour or two and read it yourself, maybe twice. If you still object, maybe send those perceived mistakes concerning radiation to:
http://www2.jpl.nasa.gov/radioastronomy/
That is the mirror site offering that same book in PDF form.
With your help, maybe they can correct their mistakes. Of course, most is also cross-reference to Kaufmann, W.J., III, Universe and that book might also need your corrections.
Sorry, my time is short and can’t chitchat things you seem not understand or disagree with. All I wrote is for others to consider.
Jose, one of your complains is clearly my mistake, in:
“Yes, GHG’s have strong absorption/emission lines and continuum but look at any spectrum of the atmosphere and this BB radiation underlies all of them”,
you are correct, should have read:
“Yes, GHG’s have strong absorption/emission lines and continuum but look at any spectrum of the atmosphere and this low emissivity radiation that follow Planck curve underlies all of them”.
I was lying trying to get some sleep mulling your comments and then it hit me, did I really type that… I think I did. Knew exactly where one of your points was aiming. Thanks for the catch.
wayne, I did not make a single complaint about that website. [not sure if you realized that on your follow up comment or not] And I quoted the other website (Larmor) to show that classical theories are not intended to be applied at all levels, even though the descriptions might sound as if they apply to atoms and what not. I didn’t find a problem (skimming a bit here and there) with the radioastronomy site. For many forms of EMR analysis, they can get away with classical analysis (although I quoted that same page talking about the value of quantum effects).
Now, I am not sure what you mean by “low emissivity radiation that follow Planck curve underlies all of them”.
Anyway, *one* reason I come back to this thread is (to learn, share, and) to defend attacks against climatology to the degree I understand the arguments and think the status quo is defensible. The burden (and likelihood of failure) is always on those trying to undermine years of work and agreement from a whole field of educated scientists focused on solving a particular problem and generally coming to agreement. Where they don’t agree, there is greater hope. Where they agree, the odds are not in Spencer’s or anyone else’s favor. That shouldn’t come as a surprise to anyone. To take over the castle, you have to get past the established and proven defenses. If you think it will be easy, you are probably underestimating something. Expect to be wrong more (perhaps many more) times than not. In fact, generally, people consider themselves students *until* they have a good grasp of the essence of the literature that was built up over time. .. but keep firing away because that will make this and future castles stronger.
RW @ur momisugly November 28, at 7:12 pm
Welcome back RW
Yes, I agree. If the atmosphere were totally transparent at those wavelengths, it would all escape directly to space. (including horizontally). Why do you ask?
Bob,
“Yes, I agree. If the atmosphere were totally transparent at those wavelengths, it would all escape directly to space. (including horizontally). Why do you ask?”
Do you also think then that it is incorrect to show the direct surface to space transmittance or ‘window’ as going all vertically from the surface to space?
RW @ur momisugly November 29, at 4:53 pm
Intriguing question RW:
Well technically it is indeed imprecise, but since the 40 W/m^2 is claimed to escape directly to space, then effectively, and for diagramatic simplicity, I think it is OK to show it that way. (I don’t know about the actual value though). Similarly, the heat transfer from thermals and evapotranspiration will have ascending isotropic emission effects, but from the cartoon arithmetic, their 17 + 80 are also claimed to escape to space, in a somewhat understated manner; that I can also live with. (putting aside Travesty’s incredibly accurate 0.9 missing heat)
However, on the other hand, the 396 S-B surface emission is in itself isotropic, and is substantially annihilated by absorption quite close to the surface. (within ~10m altitude is a popular assessment, but I’ve not seen verification, and BTW, Tim Folkerts did not dispute this number when stated severally above)
Clearly, the 396, by definition, comes from the surface, but does not make-it to space. (or even to the high clouds as shown in the cartoon). The 396 and its progeny of new-generation emissions contain horizontal vector components which cannot be seen in the normal view. Thus, the vertical components must be less than the total S-B emission.
wayne @ur momisugly November 29, at 6:58 am
Thanks Wayne, but I thought item 5) in my article explained the basics adequately. For the purpose of the article, I felt that it was enough to explain that because there is no change in temperature within a typical small regional layer of air, there cannot be any heat transfer. (heat transfer can only occur when there is a potential difference). Any more detailed explanations were in my view likely to make it more difficult for lay readers.
It’s relatively trivial, but you might be interested in an earlier draft of the article, where I did go into some finer detail, but redacted stuff after discussion with WUWT personnel:
http://bobfjones.wordpress.com/2011/09/22/is-the-trenberth-et-al-%e2%80%9cearth%e2%80%99s-energy-budget-diagram%e2%80%9d-a-travesty-a-cartoon-or-both/
Tom Folkerts says:
Look at Bob’s figure 5. There is a “bite” out of the spectrum near 15 um due to CO2 radiating from the cold upper troposphere. With more CO2 in the troposphere, the “TOA” for IR radiation to space from CO2 would be a bit higher, and hence a bit cooler.
Unfortunately fig 5 is indistinct and pretty much unreadable on my screen so can’t draw anything from it. Concerning the spectrum near 15μm due to CO2 doesn’t Wien’s law show that maximal emission λmax for that wavelength occurs at minus 80 deg C; is that the temperature of the cold upper troposphere?
At 15 deg C the temperature lower down or at ground level, maximal emission λmax occurs at wavelength 10μm.
CO2 absorbs infrared emissions from the Earth’s surface only minimally in the range 7 to 13μm and it is within this range where the greatest proportion of radiation emitted by the Earth is found. This range is called ‘open radiation window’, because it is here that the least amount of absorption by water vapour and CO2 takes place. This window allows 70 to 90% of the radiation from Earth to escape into space. It includes the peak emission.
The biggest problem with the KT graph is that you cannot add and subtract W/m^2 when talking about temperature. 10 W/m^2 of sunshine plus 10 W/m^2 of IR from atmosphere does not equal 20 W/m^2 of radiation to heat an object. It will only be heated to the temperature of the highest radiator.
>> The 396 and its progeny of new-generation emissions contain horizontal vector components which cannot be seen in the normal view. Thus, the vertical components must be less than the total S-B emission.
When photons hit a sensor or a molecule, it doesn’t matter if they come 90 degrees from the bottom or at some other angle. The point remains that the lateral photons may not hit the molecules or sensors directly above, but they hit those over on the side. The net result is the same. This is why I think the 396 doesn’t represent 90 degrees vertical but instead the entire upper half of the horizontal plane.. ie, 0<angle<180 is "up" and 180<angle<360 would be "down". The horizontal cross sections still get 396. When you say Watts/meter squared, you don't care from which angle the photons arrive.
>>
Robert Stevenson says:
November 30, 2011 at 6:43 am
Concerning the spectrum near 15μm due to CO2 doesn’t Wien’s law show that maximal emission λmax for that wavelength occurs at minus 80 deg C; is that the temperature of the cold upper troposphere?
At 15 deg C the temperature lower down or at ground level, maximal emission λmax occurs at wavelength 10μm.
<<
I tried this argument on another thread and was thoroughly chastised (by alarmists on the thread) for not knowing that Planck’s equation gives different results in the frequency domain vice the wavelength domain. That means that Wien’s law derived in the frequency domain is different than the same law derived in the wavelength domain.
Here I was taught that wavelength and frequency are related by wave velocity and were interchangeable–silly me. Ahhh, the various magical mysteries of radiation physics continually haunt us.
Jim
mkelly, that doesn’t make sense. If I have a heater on the left and another on my right and another in front and behind and above and below, I get 6 times the amount of roasting (and some temp rise based on the 4th root of total power being received from all sources in my environment.. SB) if each oven is at the same heating/power output.
A photon is a photon. If the sun keeps sending more photons and these keep bouncing around in increasing numbers because they dissipate into space slowly, then the atmosphere is getting extra power and will rise in temp accordingly.
A photon is a photon, and 6 photons are 6 photons. It doesn’t matter that they all come from different directions and originated in different places.
Jose_X, the majority of photons from the surface rollock off to deep space without even seeing a CO2 molecule. As I mentioned in an earlier post to Mr Folkerts, CO2 absorbs infrared emissions from the Earth’s surface only minimally in the range 7 to 13μm and it is within this range where the greatest proportion of radiation emitted by the Earth is found. This range is called ‘open radiation window’, because it is here that the least amount of absorption by water vapour and CO2 takes place. This window allows 70 to 90% of the radiation from Earth to escape into space. It includes the peak emission.
[Robert Stevenson]>> This range is called ‘open radiation window’, because it is here that the least amount of absorption by water vapour and CO2 takes place. This window allows 70 to 90% of the radiation from Earth to escape into space. It includes the peak emission.
Looking at this rough picture at the top section http://en.wikipedia.org/wiki/File:Atmospheric_Transmission.png, it looks like the area that is blue is much closer to 40% than to 70-90% range.
This is not a big deal, but might as well take the opportunity to link to that pic.
Jim Masterson, all the Planck’s law charts I use, plot Iλ (intensity of monochromatic emission) versus λ, wavelength in microns; I find it easier to understand and integrate on a spreadsheet. I get told off for being rooted in the 1950’s and not being upto date.
[Robert Stevenson]>> Concerning the spectrum near 15μm due to CO2 doesn’t Wien’s law show that maximal emission λmax for that wavelength occurs at minus 80 deg C; is that the temperature of the cold upper troposphere?
At 15 deg C the temperature lower down or at ground level, maximal emission λmax occurs at wavelength 10μm.
I’ll assume you are correct although I’m not sure why you mention that. Tom Folkerts specified 15, I think, in reference to the range where CO2 has an effect.
[Jim Masterson]>> I tried this argument on another thread
I don’t see what argument that was.
[Jim Masterson]>> thoroughly chastised (by alarmists on the thread) for not knowing that Planck’s equation gives different results in the frequency domain vice the wavelength domain.
Without seeing the argument I have no idea what those people attempted to say. Yes, where the speed is essentially speed of light, labeling the graph using frequency or wavelength can be done consistently and is really immaterial. It sounds to me that it would have been an odd argument.
Robert S, what are you trying to say by saying most photons don’t see CO2? Are you disagreeing with my observation that we each agree more CO2 will lead to higher temperatures of some amount and that to be precise we would have to perform calculations?