Radiative heat transfer is a fundamental factor in the energetics of the
terrestrial atmosphere: the system consisting of the atmosphere and the
underlying layer is heated by the Sun, and this heating is compensated,
on the average, by thermal radia- tion. Only over a period of 1-3 days
from some specified initial moment can the dynamic processes in the
atmosphere be considered to be adiabatic. Global dynamic processes of
long duration are regulated by the actual influxes of heat, one of the
main ones being the radiative influx. Radiation must be taken into
account in long-term, weather forecasting and when considering the
global circulation of the atmosphere, the theory of climate, etc. Thus
it is necessary to know the albedo of the system, the amount of solar
radiation transmitted by the atmosphere, the absorptivity of the
atmosphere vis-a-vis solar radiation, and also the effective radiation
flux, the divergence of which represents the radiative cooling or
heating. All these quantities have to be integrated over the wavelength
spectrum of the solar or thermal radiation, and they must be ascertained
as functions of the determining factors. The relation- ships between the
indicated radiation characteristics, the optical quantities directly
determining them, the optically active compo- nents of the atmosphere,
and the meteorological fields will be discussed in this book.