A Note on the Stefan-Boltzmann Equation - Printable Version
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A Note on the Stefan-Boltzmann Equation - Questioning_Climate - 02-02-2011 03:55 PM
Jennifer Marohasy has a new posting that may be of interest:
A Note on the Stefan-Boltzmann Equation
Quote:... Dr Curry, is the chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology and the co-author of ‘Thermodynamics of Atmospheres and Oceans’ (1999), and was speaking out against claims in a book ‘Slaying the Sky Dragon: Death of the Greenhouse Gas Theory’. ...
RE: A Note on the Stefan-Boltzmann Equation - Richard111 - 02-03-2011 02:05 AM
Thanks for showing this Q_C, very relevant to something I'm trying to work on for Derek but it shows I still have a lot to learn about IR radiation. Must go and recheck what I've done so far.
RE: A Note on the Stefan-Boltzmann Equation - Questioning_Climate - 02-03-2011 10:06 AM
No problem Richard111, glad it is helpful.
RE: A Note on the Stefan-Boltzmann Equation - Richard111 - 02-04-2011 01:03 AM
Helpful but frustrating. I have been trying to source a copy of Perry’s Chemical Engineering Handbook (Perry’s CEH) and have found only one copy available at £45 which is way over my budget level.
Seems to hold information on absorbtion/emission for CO2 down to temperatures as low as 100F. Sheeesh! Most of the atmosphere is below 32F! But the figures quoted for so called 'back radiation' are astounding! Almost zilch! That puts a nice big nail in the AGW coffin.
RE: A Note on the Stefan-Boltzmann Equation - Questioning_Climate - 02-04-2011 06:11 AM
Richard111, the following link might be useful. I've not had time to read it but skimming through, it looked relevant.
CEP (1995) Paper - Gas Emissivity
RE: A Note on the Stefan-Boltzmann Equation - Richard111 - 02-04-2011 06:25 AM
I went over to Judith Curry's blog, the source for the link Q_C posted above, and started reading some of the nearly 1,000 posts! There are some real corkers!
But the best chuckle for me was this post by Judith Curry:
Quote:curryja February 3, 2011 at 4:36pm
and where Nasif Nahle puts her right. I would post the whole thing but my computer grinds to a halt with the sheer size of that page. You have been warned!
Here is the direct LINK to a post by Nasif Nahle. (hope it works)
RE: A Note on the Stefan-Boltzmann Equation - Questioning_Climate - 02-04-2011 01:18 PM
That is certainly a long discussion. I'm sure Nasif Nahle and others will keep it on track.
RE: A Note on the Stefan-Boltzmann Equation - Climate Realist - 02-06-2011 04:36 PM
It definitely looks as though basic physics/physical chemistry does not support the existence of a back radiation propagated greenhouse effect!
Very basically, a cold object cannot heat up a warmer object, not without work input such as you get in a domestic refrigerator. Which does not exist in the atmosphere!
I'll go as far as to say that Claes Johnson is a brilliant super genius. He has spotted a flaw in the physics that totally pulls the rug from beneath the greenhouse theory. It is amazing that no-one has spotted this before. He must be a quite exceptional academic to spot this where others for decades have overlooked this issue. And luckily, something of a maverick and not afraid of controversy and a little academic conflict. His problem is (in common with the cleverest academics!) that he is not very good at explaining what he has found wrong with the physics.
I have skimmed through the comments, and this one in particular struck me as totally wrong!
"PaulM | January 31, 2011 at 8:52 am | Reply
Well, of course Johnson is wrong. It is perhaps instructive and useful to try to explain why. In the ‘blackbody’ chapter he seems to think that a warm body can warm a cooler one but not a warmer one(a warm body cannot heat a warmer body- that goes against the laws of thermodynamics- impossible !. He says at one point (sadly no page numbers) that there is two-way propagation of waves, but only one-way propagation of energythat is true!. How does that work? You clearly know no physical chemistry and radiation chemistry. A body emits radiation at a wavelength proportional to its temperature, the hotter the temp, the shorter the wavelength- and higher the frequency- hence steel when heated goes from black to red hot then white hot. A cooler wavelength has insufficient energy to heat a body that is already emitting radiation at a hotter (shorter) wavelength, therefore, the radiation is simply reflected back from the body without heating it. You would need radiation from an even hotter body (the sun for example) to heat our body (the earths surface) Are there two types of EM wave, one transporting energy and one not?! not necessary- see my previous comment. The energy is there- just insufficient to heat the body. We can also ask him this : an isolated backbody is radiating into a vacuum. Then a warmer body is brought in. How does the first body ‘know’ to stop radiating energy in that particular direction? Answer- it doesn't know, or need to "know"- but see my explanation again, the radiation from the cooler body cannot heat the warmer body
Later on he tries to use equations – but his equation (4) is just wrong. Where does this equation come from? What is u supposed to represent? Why is radiation given by the third time derivative of u?" Irrelevant as the author of this post does not understand Claes argument, he is making the same mistake that all global warmers and most skeptics make- forgetting that radiation comes in different wavelengths, which are determined by the temperature of the body that emitted the radiation- and elementary error. The shorter the wavelength the more energetic the radiation is. The IR radiation is not just "radiation" you have to specify wavelength as well as vector and amplitude. see http://en.wikipedia.org/wiki/Electromagnetic_spectrum - I think also, Claes knows he is right, but may not fulyl understand how photons interact with atoms- wavelengths and bond stretches etc and so cannot explain as well as he could- but- be assured! He IS right
RE: A Note on the Stefan-Boltzmann Equation - Derek - 02-07-2011 12:47 AM
I have said I think Claes gets the right answer, but I am not sure he gets to it quite correctly.
Which in essence was the motivation for this post,
and why I included in it so much of Claes "other" views which I also think are distinctly on the right track.
What seems (to me) to be always missing from the black body / colder thing warming a hotter thing discussions are
the appropriate plots of the spectrums of emissions of the objects under consideration.
Surely the answer lies in the overlaps of the spectrums, and the resulting final "the same" spectrum when the temperatures of the objects has equalised.
But do they indeed equalise as Climate Realist has pointed out before in referring to mass balanced equations.
I would like to see % of emission / frequency for a given temperature (or should that be energy level) spectrum plots for an object (black body),
actual amount of emissions / frequency (maybe be a unit area) for two objects
(of the same emissivity - when at the same temperature thus including any change in emissivity due to energy level differences)
at different temperatures (energy levels).
I think such plots could be very interesting, but I do not think I have seen or recall ever seeing such a plot.
RE: A Note on the Stefan-Boltzmann Equation - Richard111 - 02-07-2011 01:34 AM
People who believe in 'photons' do not realise they believe in fairy tales.
This part quote from ‘Cementafriend’, discussed elsewhere, cites Perry’s Chemical Engineering Handbook, a copy of which I am still trying to find. (can't afford new/good prices but will pay for a readable book)
Quote:Perry’s CEH states “According to Kirchhoff’s law, the emissivity and absorptivity of a surface in its surroundings at its own temperature are the same for both monochromatic and total radiation.” However, the emissivity and absorptivity needs to be considered in relation to the temperatures of the source and receiver.
Please note he is talking about pure 100% CO2, not 395ppmv!
RE: A Note on the Stefan-Boltzmann Equation - Derek - 02-07-2011 01:49 AM
(02-07-2011 01:34 AM)Richard111 Wrote: People who believe in 'photons' do not realise they believe in fairy tales.
As you know this is not really my "field" as such, but am I correct in understanding that,
"photons" are a result of the "solution" to the ultra violet catastrophe?
Where because the sums (and observations) do not work out, wavelengths (above a certain frequency) were changed to quanta
(little packets of energy called photons).
Literally, as Einstein noted, and Claes has been drawing attention to recently,
inventing quantum physics on a whim, as a convenience, to offer a "solution" to the ultra violet catastrophe..
RE: A Note on the Stefan-Boltzmann Equation - Climate Realist - 02-07-2011 11:05 AM
It makes no difference if it is 100% CO2 or 0.0395%, it also makes no difference if you consider light as being photons, waves, particles, or packets of waves. The greenhouse effect is still an impossibility on the quantum scale of electron orbitals and bond stretches for the reasons of energy of the radiation being insufficient from a cooler body to excite a hotter body on the quantum level[/b] and thus cannot heat it.
That is why there is no greenhouse effect on either Venus or Mars, despite their atmospheres being close to 100% CO2. It is the pressure of atmosphere that sets the lapse rate and hence the surface temp according to the gas laws (Boyle etc).
So, venus has 94 atmospheres and is very hot, Earth 1 atmospher and is just right, and Mars a thin atmospher so it is cold.
This is also why the lower atmosphere of Jupiter is very hot despite having no greenhouse effect also.
RE: A Note on the Stefan-Boltzmann Equation - Derek - 02-07-2011 01:59 PM
(02-07-2011 11:05 AM)Climate Realist Wrote: The greenhouse effect is still an impossibility on the quantum scale of electron orbitals and bond stretches for the reasons of energy of the radiation being insufficient from a cooler body to excite a hotter body on the quantum level[/b] and thus cannot heat it.
If there is little temperature difference between two objects then this explanation is a little "lacking",
hence my post 9.
RE: A Note on the Stefan-Boltzmann Equation - Climate Realist - 02-07-2011 03:27 PM
(02-07-2011 01:59 PM)Derek Wrote:(02-07-2011 11:05 AM)Climate Realist Wrote: The greenhouse effect is still an impossibility on the quantum scale of electron orbitals and bond stretches for the reasons of energy of the radiation being insufficient from a cooler body to excite a hotter body on the quantum level[/b] and thus cannot heat it.
Not really, because each bond stretch or movement of an electron from one orbital to another requires a certain minimum amount of energy in the radiation- this is determined by the wavelength. Bonds and electrons require a minimum activation energy before they do anything. Therefore a hotter body can emit a certain wavelenght IR to a cooler body, but the reverse case cannot occur as the hotter body is already emitting at that wavelength.
RE: A Note on the Stefan-Boltzmann Equation - Derek - 02-08-2011 04:40 AM
OK, I think "we" are tip toeing around a previous discussion we have had in regards of what does relatively absorbed mean.
I will try to explain what I mean from another angle, that I have also asked previously, but
I am not sure directly to or within discusions with Climate Realist.
Imagine a black body if you will. It will cool on it's own at a certain rate. OK.
Now, in the presence of another black body that is cooler, will the first black body cool,
1) faster, (my described all radiation is absorbed relatively)
2) slower, (all radiation is positive view), or
3) at the same rate as if it were on it's own (Claes Johnson approach).
I am also thinking that the surface temperature of the black body needs to be taken into account,
as it is not uniform (it may have an average, but that is a different thing).
I am sure I have seen this recently in a comment of someone's here, I will try and find it and replace this bit with it.
RE: A Note on the Stefan-Boltzmann Equation - Climate Realist - 02-08-2011 04:45 AM
3) is the correct answer. Claes Johnson is right. He is one of the few people in the world that has spotted the Thermodynamic flaw in the back radiation theory.
Basically, the Global Warmistas never considered thermodynamics and thus they created a false theory that has no proper basis in the physical laws of the universe.
RE: A Note on the Stefan-Boltzmann Equation - Derek - 02-08-2011 04:52 AM
Since when was assertion, ignoring, or dismissing, discussion?
RE: A Note on the Stefan-Boltzmann Equation - Climate Realist - 02-09-2011 02:28 AM
Sorry, I don't follow you?
We were talking about thermodynamics and heat, what asserts where?