INFRARED LIMB-DARKENING EFFECTS FOR THE EARTH-ATMOSPHERE SYSTEM

An infrared radiative transfer model has been developed for evaluating anisotropic functions in the longwave region (5-50 mu m) due to limb-darkening effects in the Earth's atmosphere. An accurate narrow-band model of absorption has been used for computing transmission functions of the atmosphere. Absorption due to all major and minor atmospheric constituents has been taken into account including the continuum absorption due to water vapor. Anisotropic functions have been calculated for several latitudinal and seasonal climatological-average model atmospheres. Many more radiosonde-measured atmospheric models representing a wide range of meteorological parameters have also been used in this study. The effects of the variability of various meteorological parameters, e. g. , surface temperature, surface relative humidity, and cloud-top height have been examined. It has been found that the variability of cloud parameters has the largest effect on the infrared anisotropic functions.