Schematic
diagram of radiation scheme
(Click to see how the equations are calcuated in codes!)
Brief
Introduction to radiation scheme
"The
object of any parameterization of atmospheric radiation
for use in an atmospheric circulation model is to provide
a simple, accuate and fast method of calculating the
total radiative flux profile within the atmosphere"
 Stephens (1984)
The
radiation scheme implemented in CESAGCM is based on
Nakajima and Tanaka (1986). This scheme uses discreteordinate
method and kdistribution method for the calculation
of optical thickness of gases. Total radiative
band is divided by 18 bands and the upward/downward
radiative fluxes (both for the longwave and shortwave)
at each model layer is calculated at each band.
Calculations are separately conducted for longwave and
shortwave components. To determine the radiative fluxes
using 2 stream approximation, the radiative properties
(emission and absorption/scattering coefficients)
are calculated in advance. In that part, absorption
by gases (H_{2}O, CO_{2}, O_{3}, N_{2}O, CH_{4}), continua(H_{2}O, O_{2},
O_{3}) and CFCs are considered. And the amount of
cloud water/ice
and aerosol are used for the scattering.
