Radiative Equilibrium

First uploaded on 2022/10/05
Last Updated on 2022/12/01
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Many meteorology textbooks begin with a vertical temperature profile of the Earth's atmosphere. This is because the mean field of the real atmosphere is the basic temperature field for considering meteorological dynamics. On the other hand, few meteorology textbooks include the radiative equilibrium temperature. This is because it is not necessary to be aware of the radiative equilibrium atmosphere in order to make weather forecasts. This is not the case in climatology, though.

Atmospheres in radiative equilibrium are neither heated nor cooled by radiative processes, because the heat transport by radiation is balanced everywhere in the atmosphere. On the other hand, all atmospheres that are not in radiative equilibrium will always be heated or cooled because the balance of radiative heat transport is broken somewhere within them, even if they are not subject to any dynamical forcing. Without taking this into account, it would be impossible to correctly understand why radiative cooling continues to operate in an atmosphere without any dynamical forcing (Figure 2.). You cannot accept the radiatively driven circulation (RDC) unless you are constantly aware of the difference between the radiative equilibrium atmosphere and the real atmosphere.