The Radiative Cooling Calculation for Application to General Circulation Experiments

Abstract

The Atmospheric Radiation Tables (ART) of Elsasser and Culbertson were used to calculate the atmospheric radiation, and the results are compared with those of other methods. The cooling rate calculated from ART agrees well with cooling rates calculated by more accurate methods, but the downward flux of water vapor bands computed from ART was found to be too small. This discrepancy may be attributed to smaller absorptivities used for the construction of their tables and to the assumption of the absorption coefficients at low temperature. The absorption functions in Yamamoto's chart were then used for the radiative flux calculations, and the downward flux obtained with this chart was found to be more reliable. To reduce computing time, the absorption functions of water vapor and carbon dioxide in Yamamoto's chart were expressed in the form of analytical functions. Numerical integration was carried out to obtain the net flux distribution in the atmosphere. The results compare favorably with those of Rodgers and Walshaw.