Low-Latitude Cloudiness and Climate Feedback: Comparative Estimates from Satellite Data

Abstract

At low latitudes the seasonal variation in the radiation budget of the earth-atmosphere system is due largely to seasonal variability in cloudiness. Making use of this, we have estimated, from three different sets of satellite data, the relative albedo versus infrared modifications associated with cloudiness variability at low latitudes. Employing satellite data sets due to Ellis and Vonder Haar (1976) and Campbell and Vonder Haar (1980), we find that the albedo modification is somewhat less than that of the infrared. But when use is made of radiation budget data derived from NOAA?NESS scanning radiometer measurements, the albedo modification dominates over that of the infrared by nearly a factor of 2. This obviously suggests that estimates of climate feedback associated with changes in cloudiness are highly dependent on the satellite data set which is employed. It is further suggested that these differences might be in part attributable to the NOAA?NESS data being derived from narrow spectral measurements.