Re: atmospheric blanket / greenhouse effect

[Bob LaMontagne <rlamont@POSTOFFICE.PROVIDENCE.EDU>]

Robert Cohen wrote:

> I'm no expert in radiative equilibrium, but I'll try to address the
> questions that were raised by my post:
>
> Bob LaMontagne wrote:
> > A further refinement would recognize the importance of=20
> > convection in the lower atmosphere. The average temperature=20
> > profile in the lower atmosphere is exactly that followed by a=20
> > parcel of air warmed by contact with the Earth's surface and=20
> > then rises adiabatically through the troposphere. That has to=20
> > be more than just coincidence.
>
> Actually, the average temperature profile in the lower atmosphere is
> about 6.5 K/km (according to the US Standard Atmosphere) whereas the
> temperature profile due to adiabatic cooling (assuming vertical balan=
> ce
> and no latent heating) is about 10 K/km.

One can't ignore the latent heating. The 6.5 K/km is the moist adiabatic
lapse rate. This just reiterates the importance of convection and the
presence of water in setting the temperature profile in the lower
atmosphere.

Whatever the mechanisms are that set the actual atmospheric temperatures,
you are correct in stating that fairly simple radiation balance models can
predict average surface temperatures for the Earth with surprising
accuracy.

Bob at PC