A while ago I posted a tongue in cheek thread about the old Keihl and Trenberth Earth energy budget diagram and the new shiny all colour one NASA now has on their website. Here they are again for comparison:
The major difference between these diagrams is the ‘surface radiation’ from the surface to the atmosphere and the ‘back radiation’ from the atmosphere to the surface have been replaced by a ‘net radiation absorbed by the atmosphere’ figure of 15%.
The purpose of the original post was twofold. Firstly to convert the percentages in the new diagram into watts per square metre figures so we could compare the differences. Secondly to poke a bit of fun at Keihl and Trenberth, because their overly simplified diagram has been even more simplified by NASA, they have removed the seperate up-down surface and back radiation figures altogether.
Why might this be?
In a new post over at Science of Doom entitled Do Trenberth and Kiehl understand the First Law of Thermodynamics? Part Three the Creation of Energy? S.o.D posits a simple model and offers it as some kind of vindication of the Keihl Trenberth diagram. He states:
The reason this PVC sphere model appears so wrong to many people is for similar reasons that the famous Kiehl & Trenberth diagram seems wrong – the radiation “internally” (earth surface) is higher than the external radiation to space. (Note that the radiation values in the K&T diagram can be measured).
Note the bold type.
I think this is something of a trojan horse. I don’t have a problem with some of the internal surfaces in the climate system radiating at a higher rate than the Earth as a whole radiates to space, have a look down the crater of an active volcano if you don’t believe this is possible. What I do have a problem with is that S.o.D. seems to be trying to get us to accept the correctness of the whole of the Keihl Trenberth diagram and that one of the reasons we should accept it is that the radiation values can be measured.
I asked S.o.D to point me to some measurements of upward radiation from the ocean surface and a description of the hardware used. Here is his response:
As you can see in The Amazing Case of “Back Radiation” – Part One and Part Three the measurements of upward and downward longwave radiation at the surface are few and far between due to the expense of the instruments and the setup required.
However, sufficient measurements have been done to be confident that the Stefan-Boltzmann equation is correct and so if the SST is known accurately the emission of radiation is also known accurately.
Well excuse me S.o.D but divining the upward surface radiation of a surface which contains biological matter, roughness, and all manner of dispersed chemicals is not as simple as applying a law devised for theoretically pure and smooth ‘blackbody’ surfaces to a figure for temperature and cranking out a numerical result. Furthermore, since the primary energy path in the climate system is sun -> oceans -> atmosphere you might have thought some of the $80billion spent on promoting the AGW theory might have been spared to do the job properly with empirical measurements. Unless of course those measurements might reveal something which runs counter to the theory? Maybe something that would show that John Nicol and G&T have a point or two?
I have asked for further clarification and repeated my request to be pointed to some, or even just one of these “few and far between” measurements. I’ll keep you updated.
“Recent measurements of spectral reflectances of surface
materials have clearly demonstrated that surface emissivities
deviate considerably from unity, both spectrally and
integrated over the broadband. Thus, assuming that a surface
radiates like a blackbody can lead to potentially significant
errors in surface temperature retrievals in longwave surface
energy budgets and in climate studies. ”
So S.o.D’s claim that the Stefan-Boltzmann equation for blackbody radiation plus surface temperature is sufficient to give an accurate surface longwave emission figure is falsified, along with Minnett and his skin temperature differential theory.