Top of Atmosphere Radiant Fluxes and Climate Classification

The climate is intimately related to surface radiation budget such that one can determine the climate classification of a region based on the net shortwave and longwave radiaiton at the surface. This paper explores the relations between climate classes and reflected solar radiation and outgoing longwave radiation (OLR) at the 'Top of the Atmosphere' by use of Earth Radiaton Budget Experiment (ERBE) data. Deserts are characterized by the net radiation at TOA being negative over deserts i.e. net radiation sink, in keeping with the mechanism explained by Charney. Tropical wet regions have low OLR and large absorbed solar radiation resulting in a large net radiation as required to provide the energy as explained by Neelin and Held. The boundaries between the radiation sinks and sources move with season over the trpoical wet/dry regions. Polar regions stand out as radiation sinks also. Conditions are discussed by which other cliimate classes are delineated on the basis of TOA radiation.