The Effect of Aerosols on the Earth-Atmosphere Albedo

Abstract

In this paper, calculations are presented of the change in reflected flux by the earth-atmosphere system in response to increases in the atmospheric aerosol loading for a range of complex indices of refraction, solar elevation angle and ground albedo. Results show that, for small values of ground albedo, the reflected solar flux may either increase or decrease with increasing aerosol loadings, depending upon the complex part of the index of refraction of the aerosols. For high ground albedos (A > 0.4), an increase in aerosol levels always results in a decrease of reflected flux (i.e., a warming of the earth-atmosphere system). The first part of the paper concerns itself with the computational techniques employed in this study. The method employs a numerical solution to the equation of radiation transfer and is essentially a modification of an older technique used by the authors. The modifications are detailed, and comparisons with the older technique are presented.