Satellite-Derived Surface Radiation Budget over the African Continent. Part II: Climatologies of the Various Components

Abstract

The temporal and spatial variabilities of the surface radiation budget over the African continent are examined using Meteosat data acquired during 1983?88. Continental maps of land surface albedo, downward solar irradiance, and net radiation are presented for the midseasonal months of January, April, July, and October. Surface albedo is further compared with Special Sensor Microwave Imager polarization difference of brightness temperature at 19 GHz and with the normalized difference vegetation index to assess the results and to test proposed explanations for some of the unanticipated results. An example of the latter is the finding that albedo increases throughout most of the Southern Hemisphere and in the lower latitudes of the Northern Hemisphere during the wet season. Overall, the study demonstrates the complexity of the relationships among surface albedo, vegetation, and soils and underscores a strong interhemispheric contrast in radiation regimes.