Shortwave radiation budget of the northern hemisphere using International Satellite Cloud Climatology Project and NCEP/NCAR climatological data

Abstract

A deterministic model for atmospheric shortwave (SW) radiation transfer was used with climatological data to predict the mean monthly zonal (10° latitudinal zones) SW radiation budget at the Earth's surface and at the top of atmosphere (TOA) for the Northern Hemisphere. The climatological data were obtained from the International Satellite Cloud Climatology Project (ISCCP, 1983–1990), and from the National Centers for Environmental Prediction/National Center for Atmospheric Research Reanalysis Project (1979–1995). Aerosol particles are accounted for in the study. The model's outgoing fluxes agree within 4 W m−2 on average with the corresponding values determined from the Earth Radiation Budget Experiment (ERBE, 1985–1989) satellite data. The model is able to predict the seasonal and latitudinal variation of SW TOA fluxes. Owing to the lack of a complete global climatology, the SW surface radiative fluxes predicted by our model were validated through intercomparison with other model results. Seasonal variations of mean hemispherical and latitudinal variations of mean annual fluxes are also estimated. Mean annual hemispherical values for the Northern Hemisphere were calculated for SW fluxes and for cloud radiative forcing. The model gives a mean planetary albedo for the Northern Hemisphere of 0.295, which is in agreement with 0.297±0.007 from the 5 years of ERBE data. The mean annual cloud radiative forcing for the Northern Hemisphere was found to be equal to −40 W m−2.