On the Transfer of Solar Radiation in Aerosol Atmospheres

Abstract

Abstract A radiation scheme has been developed by which the absorption of water vapor in the near-infrared regions of the solar spectrum can be inserted into the transfer program for inhomogeneous aerosol atmospheres. The incorporation of water vapor absorption in a scattering atmosphere is accomplished by a series of exponential fits to the band absorptivity based upon laboratory measurements. Band-by-band calculations have been carried out for the heating rate, local albedo, total absorption, and diffuse transmission in model hazy and clear atmospheres. In a hazy atmosphere, the solar heating rates may be as much as 5 and 9°C day−1 for surface albedos of 0.1 and 0.8, respectively. Local-albedo calculations for the entire solar spectrum reveal that a surface albedo of about 0.3–0.4 plays a significant role on the increase or reduction of a globally averaged albedo caused by the increase of aerosol concentrations in the atmospheric boundary layer. An increase of aerosol loading leads to an increase of the...