Climate Change During 1985-1999: Cloud Interactions Determined From Satellite Measurements


Author:  Robert D. Cess
Affiliation: SUNY at Stony Brook


A brief review will first be presented concerning variability in cloud cover, both as observed and as produced by the NCAR Climate System Model. Then an extension will be discussed of two recent studies that present evidence for significant decadal variability in the top-of-atmosphere (TOA) tropical radiative energy budget by combining satellite measurements of the TOA energy budget and cloud cover with measurements of the Earth’s surface temperature.  The domain studied is from 40OS to 40ON.  As in the prior studies, which were restricted to lower latitudes, there is a significant increase in the TOA outgoing longwave radiation during the period 1985 to 1999 together with an increase in solar (shortwave) radiation absorbed by the climate system.  It is suggested that these changes are related to an observed reduction in cloud cover.  But the cause of the cloud cover change is by no means obvious and might be the result of natural periodic variability acting over decadal time scales.