Radiation and gas concentration

[atlstroke]

Does anyone know of any papers describing the interaction between radiation and gas. Specifically I am trying to find out is the relationship between PPM and the flux of the radiation. At what point do the two intersect to give a measurable response and does the interaction increase linearly.

Please use common courtesy in responding.

 

[Chestermiller]

Is this question with regard to absorption of radiation and attenuation of the photon flux by molecules of a gas?

Chet

 

[atlstroke]

Chet, if I understand flux correctly it is a measure of photons present in a cross section at a given time. If it is a surface then of course the photons are coming form one side. My question pertains to a circle suspended parallel to the surface. In this case I am viewing flux as a total measure of photons coming from above and below.

So in this circle, in the atmosphere is the amount of IR fully represented by the non filtered radiation coming directly from the sun plus the IR reflected/reemitted from the ground. If these two sources do not account for the total amount of IR present, what amount is coming from excited molecules in the atmosphere emitting photons.

Do you know of any studies that looked at this to determine what portion is represented by the amount emitted by atmospheric molecules? Would also be interested in seeing if the wavelength coming from the emissions of the excited atmospheric gasses gives enough of a finger print to identify what type of molecule is responsible for the secondary emission.

thanks

 

[D H]

You're asking about atmospheric radiative transfer. Entire books have been written on this subject.

Here are a couple:
Wendisch and Yang, Theory of Atmospheric Radiative Transfer
Thomas and Stamnes, Radiative Transfer in the Atmosphere and Ocean

Here's a recent thread on this forum on a physics homework problem regarding a space probe covered by a thermal shied, with vacuum between the probe and the shield: [thread]752942[/thread]. This problem captures the basic idea of how adding additional layers (and by analogy, adding more CO₂ to the atmosphere) can increase temperature.

 

[Chestermiller]

Chet, if I understand flux correctly it is a measure of photons present in a cross section at a given time. If it is a surface then of course the photons are coming form one side. My question pertains to a circle suspended parallel to the surface. In this case I am viewing flux as a total measure of photons coming from above and below.

So in this circle, in the atmosphere is the amount of IR fully represented by the non filtered radiation coming directly from the sun plus the IR reflected/reemitted from the ground. If these two sources do not account for the total amount of IR present, what amount is coming from excited molecules in the atmosphere emitting photons.

Do you know of any studies that looked at this to determine what portion is represented by the amount emitted by atmospheric molecules? Would also be interested in seeing if the wavelength coming from the emissions of the excited atmospheric gasses gives enough of a finger print to identify what type of molecule is responsible for the secondary emission.

thanks

Here are a couple of references to papers I co-authored that show how there types of calculations are carried out:

Owens, A.J., Hales, C.H., Filkin, D.L., Miller, C., Steed, J.M., and Jesson, J.P., A Coupled One-Dimensional Radiative-Convective, Chemistry-Transport Model of the Atmosphere, 1. Model Structure and Steady State Perturbation Calculations, J. Geophys. Res., 90, D1, 2283-2311, (1985)

Miller, C., Meakin, P., Franks, R.G.E., and Jesson, J.P., The Fluorocarbon-Ozone Theory – V. One Dimensional Modeling of the Atmosphere: The Base Case, Atmospheric Environment, 12, 2481-2500 (1978)

Much of the radiative data for these models came from NASA publications: Solar photon flux vs wavelength, absorption cross sections of molecules vs wavelength, scattering cross sections of air, etc.

Chet

 

[atlstroke]

Thanks Chet, that is a huge help. As someone whose background is in medicine I am at a bit of a disadvantage when debating physics with a doctorate in quantum chemistry. Its always so odd hearing an extremely well educated man defending the topic Which Can Not Be Named. At least he isn't a vaccine denier ;)