COMPARATIVE STUDY OF THE EFFECTS OF ALBEDO CHANGE ON DROUGHT IN SEMI-ARID REGIONS.

Abstract

Results from a series of numerical simulations are presented to show the effects of changes in albedo on rainfall in six areas, two each in Africa, Asia and North America. Each pair consists of a semi-arid area lying at the boundary between a major desert and an adjacent monsoonal region, and an area of the same size located within the monsoonal region itself. The sensitivity of the rainfall to the ground hydrology was determined by performing the albedo simulations with two different evapotranspiration parameterizations, one giving too high evaporation over land and the other giving negligible evaporation over land. It is shown that with or without evaporation, the increase of albedo causes a net decrease of radiative flux into the ground and therefore a net decrease of convective cloud and precipitation. 27 refs.