On the Use of Earth Radiation Budget Statistics for Studies of Clouds and Climate

Abstract

Daily observations of albedo and outgoing terrestrial radiation derived from NOAA Scanning Radiometer measurements are used to relate cloudiness variations to regional features of the general circulation and to estimate the relative importance of the albedo and infrared effects of clouds on the net radiation balance of the earth on a regional basis. The results indicate that there are clear relationships between the variability in outgoing IR and features of the atmospheric circulation, which appear to be linked to changes in cloudiness. A method requiring only measurements of planetary albedo and total outgoing IR is devised to evaluate the relative importance of the albedo and IR effects of the current distribution of cloud for the net radiation balance of the earth. The results obtained from this method suggest that globally the effect on the radiation balance of the high albedo of clouds is two or more times greater than the effect of clouds in reducing outgoing IR, so that an increase in the fractional area of the current distribution of cloud would tend to cool the earth. In addition, very large geographical variations in the radiative effects of cloud are displayed and related to circulation features.