Layman struggles with Science

[Climate Realist]

(05-17-2011 05:17 AM)Richard111 Wrote:  In my struggle to understand the relationship between radiation and temperature and reading Joe Postma’s paper LINK where he mentions the average radiative equilibrium temperature of the Earth with the Sun as being -18C or 255K (page 11). I was reminded of one of Patrick J. Tyson’s essays:

SATELLITE DETECTION OF GLOBAL EMISSIVITY

Quote:The wavelengths of emitted photons are also a function of the temperature. In general, for any given temperature, there will be a certain frequency or wavelength that is the most probable. Most of the photons will be emitted at or near this wavelength. Wien’s Law gives this point of maximum intensity as:

λ = 2,898 / T

Here, λ is the wavelength in microns, and T the absolute temperature in degrees Kelvin.

This got me wondering as to just what was the peak emissive wavelength at any given temperature. The above little equation provides the answer.

So just what is the wavelength at 255K (-18C) == 11.3647 microns.
And at 288K (+15C) == 10.0625 microns.

Well that seems to fit nicely so what is the peak temperature at 15 microns, the favourite radiative band for CO2 ? == 193.2K Yikes! As near as dammit -80C!

So it looks like carbon dioxide molecules don’t need any particular excitation from intermolecular collisions to fire off a photon anywhere in the atmosphere below the tropopause, and some bit above.

My assertions about the kinetic energy of CO2 molecules being too low to allow radiation unless excited by collisions with other molecules is unwarranted.

Back to the drawing board and more study. My early thoughts regarding “layers” in the atmosphere, defined by penetration of 15 micron photons before being absorbed, seems the way to go. I must go back to Nasif Nahle’s paper on the subject.

Yes, this (bolded) is right, CO2 molecules are firing off IR all the time. However, the -80C temperature is another clue. The IR radiation they are firing off is incapable of warming anything on the earths surface or atmosphere above -80C! However, even "-80C radiation" will make its way out to space and thus, if anything, CO2 slightly cools the atmosphere. As -80C is still hotter than outer space.

The mistake Climatologists made in making the KT diagram their basis for the greenhouse effect from radiation is that they assume all radiation is equal and that all radiation can warm. It is not and it cannot!

This is another way of explaining my previous thread where I explained why back IR from atmospheric CO2 cannot heat the earths surface and why it cannot heat the lower atmosphere. It is simply too cold.

According to to laws of thermodynamics, heat always moves from hot to cold.

Oddly, CO2 sublimes at -78C. I wonder if that and the "close to -80C" are co-incidental?