## onsdag 2 februari 2011

In the comment Febr 1 12:28 to the thread on Slaying the Sky Dragon on Judy Curry's blog, Judy asks me:
• Do you dispute that if you put an infrared radiometer on the surface of the earth and point it upwards, that it will measure an IR radiance or irradiance (depending on how the instrument is configured)? Go to http://www.arm.gov for decades worth of such measurements. And that this infrared radiation comes from IR emission by gases such as CO2 and H2O and also clouds? If you say yes, well this is what people are calling back radiation (a term that I don’t use myself). If you say no, then I will call you a crank – all your manipulations of Maxwell’s equation will not make this downwelling IR flux from the atmosphere go away.
I address this question in Section 7.4 of my Sky Dragon article Computational Blackbody Radiation, and Judy's question indicates that she has not read my article. I explain there that an IR camera (infrared radiometer) directed to the sky measures the frequency of incoming light and computes by Wien's displacement law the temperature T of the emitter, and then by Stefan-Boltzmann's law Q = sigma T^4 associates a "downwelling IR-flux from the atmosphere" of size Q.

The IR camera thus measures frequency/temperature which by SB is translated to "downwelling IR-flux" or "backradiation". So everything hinges on this translation. Is it
correct?

Is it correct to use SB in the form Q = sigma T^4? No, because this law gives the radiated
energy from a blackbody into an environment of 0 K. But the Earth surface is not at 0 K,
but even warmer than the atmospheric emitter. The translation Q = sigma T^4 is thus incorrect in the sense that it indicates a fictitious "downwelling IR flux from the atmosphere" obtained by an erronous translation.

Judy calls me a "crank" because I say "no to downwelling IR flux from the atmosphere".

Let me then remind Judy that just saying "crank" does not mean that I am a crank in reality, and just saying "downwelling IR flux from the atmosphere" does not mean that in reality there is anything like that. Right Judy?

#### 22 kommentarer:

1. Claes its good that you brought up the question of instrumentation.
The calibration of the instrument is most important.
Also the use that the instrument is put to.
For instance if an instrument is properly calibrated to measure black body radiation by placing it in a cavity.
Then measuring its response at cavity
temperatures from +50C to -50C.
Such an elaborate process is almost never carried out.
However lets say we have such a properly calibrated instrument and point it to the night sky.
The emissions from CO2 and H2O are line spectra not continuous like black body spectra.
Do they care if they get a "reading" that the reading means anything.
When IPCC advocates lose the theoretical argument their last resort is to say "well I have an meter that proves my point".
Scientologists also have a meter called an E-meter to support their bogus claims.

Bryan

2. I agree with you completely that Stefan-Boltzmann is being routinely, even addictively misused by climate scientists, so your answer here is right to the point: That climate scientists are fundamentally deluded in trying to apply only radiative transfer theory to the atmosphere, at the expense of the real, complex physics. Amazingly, they short-circuit the entire atmosphere when they presume the Earth's surface to be a blackbody. But I see little chance that Curry will heed your words, much less give them any respect. She and all the other "97% of climate scientists" will have to jerk their thoughts around 180 degrees to do that.

As for why "physicists say nothing", what is there to say to a wayward, headstrong climatologist beyond, "you are using Stefan-Boltzmann wrong here, and here, and here, and...." And if they can't say that, it's better they say nothing. Anyway, the wayward Curry is plainly telling you she is not disposed to listen, because she has chosen her "side" and the ballgame is in play. It is such a pain to change your mind, when your side is driving the ball downfield, or even over a cliff.

3. It would help if physicists said something, but I guess they are fully occupied with string theory, quantum loop theory and multiverses, and have little to say about Maxwell's equations and radiation.

4. This is a revolutionary time, when the consensus is incompetent, and it is an amazing fact that, so far, very few are capable of saying, "the emperor has no clothes." I once briefly presented my own work to a physics department head, at the end of which she said, "I just try to keep my head down." At bottom, it is due to the reigning belief paradigm of Darwin, "survival of the fittest." The truth is, only the truth survives, but that requires a long view (indeed, a spiritual view). We can only engage the world as it is, and hopefully be the agents for the correction that must come to science, and seems long overdue. I agree with you also about string theory and quantum theory, but at present all one can point to is their barrenness in the struggle to bring forth more true knowledge, as proof of their uselessness.

5. Would like to challenge backradiation believers to construct a cooling bag for cooling beer that is based on the phenomenon backradiation! I volunteer myself to test it during next summer :>)

Tomas

6. johnosullivan

http://johnosullivan.livejournal.com/18334.html

"BYU's study entitled, ‘Solar Cookers for Developing Countries’ shows that the predicted harmful back radiation effect defined by the greenhouse gas theory (GHG), whereby carbon dioxide in the atmosphere is supposedly responsible for re-radiating heat energy (repeatedly up and down as if under a blanket) doesn’t exist in the real world."

7. In other words, Maxwell's equations are dead. These equations can't explain the frequency spectrum of blackbody radiation. They can't explain why electrons accelerating under the influence of nearby protons don't emit radiation. The don't explain the existence of lasers and masers. Most of all, they aren't consistent with the particulate nature of light. You can, of course, find numerous situations where Maxwell's equations and quantum mechanics make indistinguishable predictions. However, when these predictions disagree, Maxwell's equations turn out to be wrong.

You may have discovered a modification of Maxwell's equations that allows the modified equation to properly predict the spectrum of blackbody radiation. TO BE USEFUL, your modification needs to give the correct answer in all other situations where Maxwell's equations disagree with QED and observation, especially situations where light appears to behave like a particle. Until then, it is senseless and irresponsible to speculate about interactions between radiation and the atmosphere using an theory that was proven to be incorrect a century ago.

Even better, you need to identify some situations where your modification of Maxwell's equations and QED give different answers and then see which theory gives the correct answer. In theory, you have already identified such a situation - radiation emitted downward from the atmosphere. Which theory is correct?

You can see some examples of IR spectral data for downward radiation at http://scienceofdoom.com/2010/07/24/the-amazing-case-of-back-radiation-part-two/. SOD also has references showing the agreement between observed and theoretical DLR calculated using overhead temperature and humidity data obtained from a radiosonde.

I'm skeptical of what the IPCC is telling us about AGW, but abandoning well-established scientific theories about radiation for new untested hypotheses isn't going help and hurts the credibility of all skeptics until there is substantial evidence showing the new hypotheses are more relevant than established theory.

Frank

8. Maxwell is dead but not his equations which describe macro physics beyond the
realm of quantum mech.

9. No, quantum mechanisms describes all macro and micro physics that can be explained by Maxwell and cannot be explained by Maxwell. To supplant QM, you need to explain everything known that is consistent with QM and at least one phenomenon that is not consistent. [A theory that gives the same results as QM (some sort of unification theory, for example), would be valuable, but wouldn't change QM's predictions for atmospheric phenomena.

(Some of my previous post was lost by the blog software.) Frank.

10. Above you mentioned lack of input from physicists. I suggest the introduction to QED (Quantum Electrodynamics), a series of popular lectures by Feynman. p15: "I want emphasize that light comes in this form - particles. It is very important to know that light behaves like particles, especially for those of you who have gone to school, where you were probably told something about light behaving like waves. I'm telling you how it does behave - like particles." "If you put a whole lot of photomultipliers around and let some very dim light shine in various directions, the light goes into one multiplier or another and makes a click of full intensity. It is all or nothing: if one photomultiplier goes off at a given moment, none of the others goes off at the same moment... There is no splitting of light into "half-particles" that go different places." "Every instrument that has been designed to be sensitive enough to detect weak light has always ended up discovering the same thing: light behaves like particles." p14: "If we ... could see ten times more sensitively, we wouldn't need to have this discussion - we would have all seen very dim light of one color as a series of intermittent little flashes of equal intensity."

Phenomena of this type killed Maxwell's equations. If wave equations can't reproduce all aspects of this "particulate" behavior, they are worthless. Frank

11. A little more of Feynman's wisdom on understanding physics from QED (p10) :

"The next reason that you might think you do not understand what I am telling you is, while I am describing to you HOW Nature works, you won't understand WHY Nature works that way. But you see, nobody understand that. I can't explain why Nature behaves in this peculiar way.

Finally, ... I'm going to describe to you how Nature is - and if you don't like it, that's going to get in the way of your understanding it. It's a problem that physicists have learned to deal with: They have learned to realize that whether they like a theory or they don't like a theory is NOT the essential question. Rather, it is whether or not the theory agrees with experiment. It is not a question of whether a theory is philosophically delightful, or easy to understand, or perfectly reasonable from the point of view of common sense. The theory of QED describes Nature as absurd from the point of view of common sense. And it agrees fully with experiment. So I hope you can accept Nature as She is - absurd." Unlike Feynman, Planck and Einstein didn't have the benefit of seeing an older generation of physicists rendered obsolete because they insisted looking for a common sense theory that explained why things happen, rather than a pragmatic theory that explained what actually happens.

"Experiments have Dirac's number at 1.00115965221 +/- 0.00000000004; theory puts it at 1.00115965246 +/- 0.00000000020 .... By the way, I have chosen only one number to show you. There are other things in QED that have been measured with comparable accuracy, which also agree very well. Things have been checked at distance scales that range from one hundred times the size of the earth down to one-hundredth the size of an atomic nucleus. These number as meant to intimidate you into believing that the theory is probably not too far off!" p7 Frank

12. No, QM is useless for macrophysics because the wave function is viewed to depend on 3N variables for N electrons.

13. Finally, we come to Feynman's infamous "Cargo Cult Science", which is available on the web at: http://calteches.library.caltech.edu/51/2/CargoCult.pdf

Since that is short and freely available online, I don't have to quote from it.

None of this has been meant as an "appeal to authority", just a measure of the size of the mountain that needs to be climbed Frank.

14. "No, QM is useless for macrophysics because the wave function is viewed to depend on 3N variables for N electrons. "

That is a meaningless statement. Depending on a large number of variables does not mean that nothing at all can be predicted. As an example, a simple average of N quantities can be evaluated for huge values of N. Often there are additional symmetries which help us evaluate even quite complicated functions on a macro scale.

Maxwell's equations which you want to modify and use have same type of dependencies since they depend on the precise detailed shape of the domain boundary.

15. OK, let me then ask you to predict the propagation of electromagnetic waves in the visible spectrum say, using QM. Can you do that or anybody else?

16. Your question is ill defined since you do not say what you mean by "propagation of electromagnetic waves in the visible spectrum"

The emission rate of photons can be calculated. The expected absorption rate of photons in a gas can be calculated.

But more to tho point. You asked a counter question instead of saying why your own modified Maxwell's equations do not have exactly the same problem which you accuse QM of having. So I'll do the same. Why does not your equations have the same problem?

17. Let me then ask you for the QM mathematical model showning the propagation of a photon?

My model is a deterministic macroscopic continuum wave model subject to finite precision computation. QM is (in the Copenhagen interpretation) a microscopic statistical particle model.

The difference between the models is immense.

18. That "model" is given directly by the Schroedinger equation, which give the time evolution of the probability amplitude for the photon.

The differences between the models are indeed immense. The main difference being that QM has passed every experimental test it has been put to, and your model is a truncated model incapable of describing anything but the single thing you have tried to make it model.

19. Can you describe which version of the Schrödinger equation has the propagation of a photon as its solution?

20. Since you refuse to explain why your model is not "useless for macrophysics" as you say that QM is I will not humor you by repating the basic course in QM here.

You say "QM is useless for macrophysics because the wave function is viewed to depend on 3N variables for N electrons."
Why does your model not have this problem itself when it depends on the precise details of the physical environment in which the waves travel, the exact shapes of boundaries and exact local densities of the gases?

21. The Schwartzschild equation contains the predictions of quantum mechanics for radiation traveling through a gas. For light of a given wavelength):

dI = -nkI.ds + nkB(T).ds

The incremental change in the intensity of the radiation (dI) as radiation of a given wavelength passes an incremental distance (ds) through a gas has two components: 1) An absorption term that is proportional to the number of absorbing/emitting/GHG molecules (n) and the intensity of the radiation (I). 2) An emission term that is proportional to the number of absorbing/emitting/GHG molecules (n) and Planck's function, B(T), for that wavelength and the temperature of the gas. The constant of proportionality, k, is called the absorption or emission coefficient and is the same in both terms because emission is the same as absorption with time running backwards. For total intensity, one integrates over all wavelengths.

One presumably doesn't need the Schrodinger eqn to derive the Schwartzschild eqn. Derivations of Planck's Law use an enclosure with a "photon gas". If one places a gas capable of absorbing and emitting radiation inside the same enclosure (Planck's oscillators, if you like the analogy), the intensity I used the absorption term will contain B(T) and the emission term needed to produce equilibrium will also contain the same factor. The Schwartzschild equation is consequence of the Planck's work, not later QM

22. Anonym 200211 08:44 You seem to be mixing up waves and photons. Claes has made his analyses around threshold energy levels which can be received by a body. This make some sense from engineering measurements. Another explanation could be that higher intensity outgoing waves from a source cancel lower intensity incoming waves from lower temperature sources and the opposite effect at receivers where high intensity waves from higher temperature sources cancel any outgoing waves. This results in a net flow only from higher temperature to lower temperature.
Your explanation of absorption in terms of number of molecules is basically what Prof Hoyt Hottel found by measurements in heat exchangers. The absorptivity is a function of the partial pressure of absorbing gases. The absorptivity is also a function of the wavelengths that the receiver can absorb (ie its total emissivity) and the temperature and emissivity of the source. Now considering the trace amount of CO2 in the atmosphere it can be calculated that the absorptivity of CO2 (from the two factors very low receiver emissivity and very low quantity present) is insignificant in the radiant loss from the earth surface (which is also a variable unknown amount due to other heat transfer).