How does sun heat the air?

On Oct 9, 10:47*am, Tim Taylor wrote:


Evan,

While the long wave does have a greater input back into the total
atmosphere and to radiation back into space I think in the boundary
layer conduction and convection are still the primary sources of heat
transfer. * *Since the air is primarily oxygen and nitrogen that are
both opaque to long waves as well it it mostly the other sources that
generate thermals.

Hey Tim,

I think you'll find if you dig into this that it's long wave
radiation, plus convection (thermals + wind) and evaporation/
condensation. Conduction is a bit player.

See second two answers here, though I cannot vouch for numbers
http://www.newton.dep.anl.gov/askasc...0/wea00082.htm -- the first
response given is in error. There must be something better on the
web, but I can't find it quickly.

What's missing here is useful info on absorption coefficients and heat
flux vs wavelength and water vapor content. But what I am given to
understand here is that most of the heat energy that drives thermals
we can use comes from long wave infrared transmitted from the heated
surface and absorbed in the first few feet / tens of feet / hundreds
of feet. I cheerfully admit I don't have the time to go get the
details to back up my case

Best,
Evan Ludeman / T8