Solar absorption by atmospheric water vapor: a comparison of radiation models

Abstract

We have intercompared several different procedures for evaluating solar absorption by atmospheric water vapor, and in particular we have employed a random band model as a diagnostic tool for assessing approximations which are inherent in existing parameterizations. We reaffirm McDonald's (1960) conclusion as to the importance of the 0.72 and 0.81 μm water vapor absorption bands, and we find that the Goody random band model and the Lacis-Hansen empirical parameterization produce comparable tropospheric heating rates. This agreement does not extend to the stratosphere. for which water vapor amounts lie outside the intended range of applicability of the Lacis-Hansen parameterization. But when diurnal averaging is taken into account, the disagreement is reduced. We further present what is in effect a two-parameter extension of the Lacis-Hansen parameterization. DOI: 10.1111/j.1600-0889.1985.tb00055.x