1. Bryce, here is additional information that was sent to me privately that may help you. I quote:

    To begin with, the article claims that the calculated "backradiation" that is 1/10 of IPCC/K&T numbers. There is a clear problem because the "backradiation" (a.k.a. "sky temperature" or "Downwelling Longwave Irradiance") has been routinely measured at many observatories and universities. Here is an example of the device they are using

    The K&T/IPCC number comes from these direct wideband measurements, not from some theory. Therefore the calculated 10x discrepancy is direct evidence that the article is fundamentally wrong. Strangely, it is hard to get data about all-sky radiation measurements. Maybe it is because this subject was settled 50 years ago.

    Here are some references, once you find the right term to search, "Downwelling Longwave Irradiance":

  2. I cannot argue against the measurements have been made to show that the Trenberth-IPCC back radiation values match the measure values of "downwelling" radiation. However, I can question the appropriateness of using that value in greenhouse heating calculations based on the assumption I made. Namely that we should start with the earth IR and go from there in caclulating CO2's effect on earth temperature. If we use both the earth's temperature (288 C) and the downwelling radiation as sources of IR radiation for greenhouse heating, we are double counting because the "downwelling" heat contributes to making the earth's temperature what it is. There is a current controversy over use of back radiation.

    If you read my paper all the way through, you'll note that I did use the back radiation as a source so I could compare my methodology directly to what Petschauer had done. When I did this, I verified Petschauer's results, namely that CO2 is merely "a bit player" in earth warming. When I use the back radiation value that I calculate with SpectralCalc, I show that CO2 doesn't even get "walk on" role. My methodolgy doesn't depend on assumptions about the magnitude of back-radiation. It still shows that the effect of CO2 has been greatly exaggerated.

    The comments that appeared regarding Petshauer's paper (G5) do not apply to mine (G4).

    Bryce Johnson

  3. @00, Does anyone here have hands-on experience running Hartcode?

    I understand Hartcode is the accepted standard for doing atmospheric radiation calculations. If this is true, do we know what result Hartcode would produce using the same initial conditions as the calculations run by Bryce?

    Did the IPCC use Hartcode to run its calculations?

    Bryce, do you know how your calculation method differs fundamentally from Hartcode?

  4. Brice,
    There is a lot to discuss here, but it is so involved that I need to simplify to basic issues. The long wave gas absorption near the ground does not matter except to prevent most of the long wave radiation from the ground from going directly to space. The net result is that the radiation to space occurs above the ground, and the approximate average location is about 5 km. The radiation to space has to match (on average) the incoming solar absorbed radiation. The "effective" temperature of the clouds and average source gas for the match generate the equivalent black body temperature of near 255 K at that effective altitude. The environmental lapse rate (wet and dry adiabatic lapse rates, plus some selected inversions) average -6.5 C per km, and thus the 5 km altitude adds about 33 C added to reach 288 K average surface temperature (this is crude but basically valid far as I can see). The adiabatic lapse rates are driven directly by convection from solar heating at the ground and day/night and latitude variation in heating.

    The effect of adding CO2 would not be from changing the optical properties of most of the atmosphere but from changing the location of outgoing radiation. The effect is to slightly raise the average altitude (due to more absorbing/radiating gas at the higher altitude), so the lapse rate times added altitude adds a bit more surface temperature. The atmosphere is partially long wave radiation insulating, but open to free convection, and this results in the atmospheric greenhouse effect.

    the so called back radiation is nothing but the long wave radiation (globally radiated) from the atmosphere back toward the ground based on the LTE of the local atmosphere temperature and presence of suitable absorbing/radiating gas (mostly water vapor) .

  5. Bryce wrote, "I can question the appropriateness of using that value [333W/m2] in greenhouse heating calculations based on the assumption I made."

    I am unsure how this statement fits into scientific method we try to practice here. There is a measured quantity, it directly affects energy flow balance at the surface. You cannot dismiss this value and consider it "inappropriate" based on your own assumptions and your unconventional vision of heat-mass transfer model.

    Now, you say: "Namely that we should start with the earth IR and go from there in caclulating CO2′s effect on earth temperature."

    Yes, this is a noble goal. However, your theory seems to assume only one factor at Earth surface, the blackbody IR emission. You even don't count the necessary and inseparable process of downward radiation on the surface energy balance. This is not any "double count", nor there is any controversy: the heat TRANSFER from a surface is always a net transfer, a difference between incoming EM wave and outgoing EM wave. They are inseparable. Convection and latent heat transfer are also excluded from your consideration.

    Your model is in fact a well-known radiative-only "glass-slab" model, which was employed 50-100 years ago and was shown to be vastly inadequate to the task. The radiative transfer science is far past this point. Why the article has no references to any radiative transfer papers? The approach is no different, so if you would do all calculations correctly, you would have the same standard CO2 "forcing" of 3.7W/m2 from AGW.

    The article language is vague and uncertain. It is difficult to wage through refrigeration engineering terminology of "heat rejection" and "energy deposition profile". Instead of general references to "first law of thermodynamics", you should specify more explicitly which "body" you are talking about, which "steady temperature" it has and where (because it does not have it), why do you believe that rarefied gas emits as blackbody.

    The article seems to assume that the only change in "heat input" happens due to changes in "fractional heat addition" due to increase in amount of absorbent [CO2]. This is not true. In fact, changes in radiation balance at surface level have no effect whatsoever on overall "heat input", because convective instabilities and corresponding stirring would re-arrange any changes and restore the necessary lapse rate. The only effect of increased air opacity happens at the radiative top. Please consult with Article G2 for details, and tell where do you disagree with described physical picture.

  6. Response to Dr. Ed:

    The descriptions of Hartcode and SpectralCalc are very similar, but I can't tell if they are the same. They both have enough internally generated atmospheric parameters that one would have to have good control on these to do a test case. And it may be difficult to get those parameters from the code providers.

  7. Response to Leonard Weinstein

    Thank you for responding to my request for a review.

    It seems to me that you are relegating too much insignificance to the direct IR radiation from the earth's surface to outer space. All energy balances I have seen report this as roughly ten percent of the total insolation to the earth and atmosphere. Admittedly ghg's do lower that value but since direct radiation is 60 percent of all the long-wave radiation that starts out, the lowering cannot be very significant. I think your analysis did cover this OK.

    I agree that the effective altitude of emission to outer space moves outward as the greenhouse heat increases, but I think it is due only to the change in temperature decline (lapse rate) which is cause by added heat to the atmosphere at elevations where molecular concentration is sufficient and where complete saturation has not yet occurred. A flatter temperature decline moves the average temperature outward.

    My analysis showed that as the effective emission temperature moves outward, the calculated average heat increase to the atmosphere decreases.

    I agree with your description of back radiation.

    Response to Al Tekhasski.

    Thank you for responding to my request for a review.

    Other commenters have pointed out that the actual measured back radiation matches that of Trenberths heat balance. You are right that I should not dismiss this. And for the case where I included it, it may not have been included correctly. This obviously needs more work and thought on my part.

    I don't disagree that heat TRANSFER is always a net heat transfer, but that does not preclude the incoming and the outgoing from being treated separately. I believe that convection and latent heat transfer have only a secondary effect on what is happening relative to IR transfer and that it is OK to neglect them.

    I was totally unaware either of the "glass-slab" model, that it matched my model or that it is vastly inadequate for the task. Thanks for the education.

    My radiative transfer calculations were all done with the SpectralCalc code. I felt that referencing it obviated the need for references to additional radiative transfer papers.

    What is the approach no different than? I presume you are stating that because I did not reference "radiative transfer papers" that my analysis is incorrect. If this is your inference then I flatly reject it.

    I apologize for my lack of articulation and clarity and the use of engineering terminology. If you are troubled with "heat rejection" and "energy deposition profile" I am willing to substitute more scientific terminology. My specific application of the first law of thermodynamics was to the atmosphere as a whole as the body I was talking about. I thought this would be evident. I recognize that its temperature is not steady, but that there is no compromise of results if I assume that it is steady or at least stable for a relatively short period of time. To do otherwise would complicate the analysis without adding information.

    I am only interested in the results of change in "heat input" due to CO2 absorption. Why should I include everything else? If you are inferring that such exclusion invalidates my analysis then that is a different matter and you should say so and say why. One thing that my analysis did show (and you may not agree) is that the temperature lapse rate per se has but a minor effect on average temperature of the atmosphere. All the sophisticated studies of convective instabilities and corresponding stirring in the world will not alter the lapse rate enough to amount to anything. And, as I stated, lapse rate is a minor parameter in determining overall atmospheric temperature. Using 288, 255, or 233 as the effective Kelvin temperature of outbound radiation won't alter the average atmospheric temperature by more than a small fraction of a degree centigrade.

    I don't believe the statement that "the only effect of increased air opacity happens at the “radiative top" whatever that is. Maybe that's the only place where it has to be accounted for in analyses. But the effect of increased opacity is manifest everywhere in the atmosphere that it exists.

    I read your G2 article and I have no disagreement with it. What I don't have, however, is any sense of how I should alter my analysis because of it.

  8. Bryce, regarding "actual measured back radiation matches that of Trenberths heat balance."

    This is not that the measured radiation "matches" the number on K&T picture; almost all numbers on K&T pictures are taken from observations, that's why they "match". For example, the "latent heat" part is estimated from data on rainfall — whichever comes down must evaporate from somewhere. SW reflections are measured, long-wave radiation from surface is estimated from measured temperatures and known surface emmissivities, etc. etc. I don't understand why people are so against this diagram. It represents approximate current heat fluxes, nothing more, it is a static balance. It is nearly impossible to derive from this balance any projections for climate sensitivity to any changes.

    Regarding "Spectralcalc code", there are several different sections. I assume that you are using a subscription version for calculating of atmospheric path irradiance,

    Is this correct? I cannot understand from your article how do you obtain changes in surface temperature from that, and how do you change "backradiation" at will. All you show are transmittance spectra. In my understanding, every layer of air is in Local Thermodynamic Equilbrium (LTE), so whatever temperature it has is translated into radiative fluxes invariably. Each layer has its own transmission-absorption properties and is held at its own temperature, all of them are changing with height, including line broadening. Therefore each layer emits accordingly and differently, and each individual frequency has different mean free path before being absorbed in adjacent layer. Every line must behave differently. Please explain.

  9. @ 7 Bryce,
    There is a small portion of direct radiation to space and some radiation absorption and some radiation in the atmosphere from greenhouse gases (and aerosols and water drops), but the main transfer of heat from the surface to high altitude is evapotransporation and convection up of air heated by conduction and buoyancy. The radiation to space occurs at all altitudes, with the effective average altitude about 5 km. Due to free convection and LTE, the average lapse rate DOES NOT directly change due to changes in the greenhouse gas concentration, but can change slightly due to changes in average cloud cover. The effective temperature of the average altitude where radiation to space occurs (and this average includes the surface direct to space) does not drop as the average altitude for radiation to space increases. The effective increase in altitude times the effective lapse rate is then the CAUSE of increased ground temperature. The increased ground temperature, and increased atmosphere temperature close to the ground then both increase radiation levels, but the heat transfer stays the same.

  10. Brice,
    Consider a gas that is nearly totally opaque to outgoing radiation (all wavelengths), but radiates to space at the same altitude as present. The radiation heat transfer is zero. The temperature profile and ground temperature would be the same as present if the location of outgoing radiation to space was the same, and the specific heat of the gas was the same. All energy would be transported from the ground to the radiation height by convection. The fact that the gas absorbed more radiation has no effect due to LTE and free convection.

  11. Reply to Comment 8, Al Tekhasski

    Hope this goes, the last one failed. You are correct on your question about SpectralCalc. In my use of SpectralCalc, I didn't calculate any surface temperatures, only the temprature increse in the atmosphere. I used he 288K temperature of the earth's surface as the starting point for SpectralCalc and I maintained it constant.
    SpectralCalc divides the atmosphere into think concentric spherical annuli out to 120 km. Each annulus has its own atmospheric parameters, so that any one calculation has as many sets of parameters as annuli crossed by the total path length. Each line is calculated separately. That's why the wavelength interval whih can be calculated is limited. I used 20 inervals in getting across the IR specrum of the earth. SpectralCalc rejects you input if you exceed its million-point calculation limit and has you reduce a least one of the limiting parameters. It tells you what point count would be required to help you adjust the limits (as path length of wavelength interval). I don't remember, if I ever knew, the thickness of the radial annuli used. If the code accepts your input it gives you all the accuracy needed. I.e., you don't improve on the accuracy by dividing up the interval for more calculations.

    I tried to use it to calculate back radiation, but you noted that my effort fell short of the IPCC value by a factor of ten. The scheme i used for that is described in the paper. I now have a scheme using the down-directed path scheme to see if I can determine the atmount of heat dumped in the atmosphere while it is delivering 333 watts/m^2 to the earth's surface. I'll describe it to you if it works (maybe even if it doesn't work, so I can get your input on it). I found that the parts of spectralcalc that were free did not meet my needs, the $25/month fee was well worth it.

    If you need more clarification, ask.


  12. Bryce, the text says:
    "2. From 1, altitude energy deposition profile was obtained and is shown in Figure 9."

    Where is Figure 9?

    Could you please explain what is the "altitude energy deposition profile"?

  13. Reply to number 13 from Al Tekhasski

    Figure 9 is actually Figure 8. I caught that error and a few others, unfortunately, after I'd sent off the original. I sent a corrected one, but Dr. Ed has been too busy to replace the first one. I apologize for that.

    The energy deposition profile is the relative energy depositied in the atmosphere at the specific altitude. It was obtained by normalizing to the top energy deposition, calculated at 0.5 km. Meaning the plotted values are the values calculated by dividing by that at 0.5 km. I obtained that because I wanted to know far into the atmosphere effective depoisition was seen.


  14. KUDOS to Richard for taking a pragmatic view of the the"greenhouse" phenomenon. About everything he did was according to my instincts, as I have been expressing here for the last month or two. Way to go!

    Two items:

    1- The 10:1 disparity between G 3 back-radiation from the atmosphere and your results means that there is a fundamental difference in the assumption made by you and by them. This needs searching out. One thought was the geometrical modeling of the diffuse back-flow of energy by the two camps, the watts per micron per steradian metric, has fundamental differences in detail. I think you said that the G5 result was based on actual measurements a century ago. This task now seems clear: You must obtain those papers and reports that produced those (high flux) results and very carefully extract their underlying diffuse geometry assumptions. For instance, I believe that you are basically expressing a one-dimensional model of the progression of radiation from the surface up (+) into the atmosphere and then back (-) to the ground. One needs to carefully consider whether radiation traveling to the right, left, fore and aft are to be counted, or not.

    2- In my brief study, I found a graph that shows atmospheric temperature from the ground through the Exosphere toward outer space (produced in these general "Ed vs Eric" writings as @20 therein, I believe). There it is clear that the stratosphere is VERY cold while the outer Exosphere is VERY hot. How do we now explain this stark contrast having your excellent computational capability… I say that this is due to the rather complete absence of polar molecules of gas that are responsible for IR absorption/re-radiation. Mix in with this the likelihood that CO2 concentration out there might be lower percentage wise because of its greater molecular weight. This high temperature exists in the face of no visible or IR absorption. But this layer is first in line to be exposed to ultraviolet, whose interactions cannot be polar where there re no polar molecules, but UV interactions can be atomic; amongst the outer atomic electrons. Ergo, this uppermost layer is warmed by ultraviolet energy absorption by day, but cannot re-radiate it at night. This is then the perfect greenhouse envelope! The natural extension of this conclusion is that any addition of polar molecules to the atmosphere results in its cooling!

    What say you?


  15. Reply to Dr. Eric, comment 16.

    There is no theory here, it is just an application of the simplest physics that adequately describes the situation.

    All the "facts" appropriate to the situation have been applied and results compared.

    Perhaps you and Mr. Twain can consult with each other and explain to me which facts have been omitted

    Bryce Johnson

  16. Reply to comment 17.

    This comment obviously addresses G5 by Petschauer, but posted under G4, apparently in error.

    Bryce Johnson

  17. Richard Petschauer says:
    February 5, 2011 at 7:31 am (Edit)

    My comments on this are rather late, but I have noticed a number of problems.

    But first regarding the general approach. It appears you are trying to improve on my paper from 2008 that only considered the heat transfer between the surface and the atmosphere. However this method has the shortcoming in that the constraint of the outgoing radiation must balance the net incoming radiation is not considered. All the current models invoke this balance at the planet level. However in doing so these methods seem to then ignore the surface to atmosphere coupling and assume a constant temperature relation between the surface and the top of the atmosphere. My latest paper “Climate Science’s Blind Spot – Evaporation Cooling” attempts to combine both methods and solves for heat balance at all three levels: the surface, the atmosphere and the entire planet to outer space.

    Some detail questions about your paper.

    The “saturation” region for CO2 after 20 km of travel is from 12 to 18 microns, but you seem to use only the left side of this, or 13 to 15 microns.

    Also your Figure 1 shows very low absorption in the 13 to 15 micron region, about 7%. Why is this being shown? What is the path in the atmosphere for it? Figure 6 shows only about 9% absorption in the 13 to 5 micron region.

    Your absorption numbers in Table 1 look low. For example for present CO2 and water vapor you show absorption of 244.64 w/m^2. This is only about 62% of the 396 leaving the surface. My results and Trenberth’s estimates are close to 75% for clear skies.

    But then in Table 1 from line 4 to 5, the values are reduced by 10 to 1 (1.047283 drops to 1.004723). What is the basis for such a large reduction? That implies the total absorption is 10 times 244.64 which is much larger than 396 leaving the surface. Apparently this comes from a statement earlier, “The greenhouse contribution to total atmospheric heat is assumed to be ten percent.” Looking at Figure 2 including clouds it is 356 / (356 + 78 + 17 + 80) or 67% about half of that if clouds low intercept about 49%. However all that the atmosphere can capture by GH gases is the radiation of 390 or 396 leaving the surface.

    You show two values of water vapor content whereas it drops with altitude with temperature. How was this handled?

  18. Richard

    Thanks for your comments.

    I used the known temperature of the earth's surface (288K) as the starting point for my calculation. The value already contains the effects of exchange of IR at the earth's interface.

    I used all the IR range for my calculations. The increment between 13 and 15 is only one of these. Did I fail to note that this was only and example of one of the twenty increments used? I used the average of 5 paths through the atmosphere for each increment of wavelength. This is described in the paper.

    All three of the atmospheric heat balances show only about 40 percent of the surface heat absorbed in the atmosphere. Secondary emissions don't count as heat to the atmosphere because these are produced by the heat that is already there.

    I omitted any direct concern with clouds, assuming that was covered in my average moisture in the atmosphere. My goal was to obtain a reasonable estimate of the CO2 contribution with minimal necessary calculations.

    CO2 contributed about a 0.04 fraction of the greenhouse heat which I assumed was ten percent of the total heat. So CO2 contributes 0.004 to total atmospheric heat.

    Bryce Johson

  19. addendum to comment 22.


    I did not vary moisture content with altitude but used an average value throughout the 20 km calculation altitude.


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