An investigation of cloud/radiation interactions using three‐dimensional nephanalysis and earth radiation budget data bases

Abstract

The cloud climatology data obtained from the analysis of the Air Force three‐dimensional nephanalysis (3DNEPH) cloud data base and the broadband radiation budget data derived from the Nimbus 7 earth radiation budget (ERB) measurements, are compared on regional, zonally averaged, and hemispheric scales for January and July 1979. The analyzed cloud climatologies are also compared with existing cloud climatologies and general circulation features. In addition, they are used as input to an IR parameterization model to calculate the emitted IR flux at the top of the atmosphere. These model fluxes are subsequently compared with the ERB flux climatologies. An investigation of the sensitivity, at 1200 and 2400 local time, of the reflected solar, emitted IR, and net radiation to changes in cloud amount on a regional, zonal, and hemispherical basis is then carried out employing the 3DNEPH and ERB data. The daily net radiation sensitivity factors for the northern hemisphere for January and July, with values of −8.1 and −50.9 W m−2, respectively, compare reasonably well with those obtained by other investigators.