On the Interannual Variation of the Earth Radiation Balance

Abstract

The interannual variability of the top of the atmosphere net radiation budget as measured from the Nimbus- 7 Earth Radiation Budget instruments was calculated for an eight yew period 1979?1986. The largest fluctuations are shown to occur in three tropical areas. the Atlantic off the west emit of Africa, the eastern Pacific near South America, and the western Pacific northeast of Indonesia. The variability in the Atlantic was 20% greater than in the eastern Pacific and 35% greater than in the Indonesian area. The maximum anomalies in these two Pacific regions occurred during the El Niño year 1982?1983, while the maximum Atlantic anomalies. south of the Gulf of Guinea, were during 1984. An independent dataset of derived cloud type and amount from the Temperature Humidity Infrared Radiometer (THIR) and the Total Ozone Mapping Spectrometer (TOMS) instruments shows interannual changes in multilevel convective cloud systems have a minimal effect of the net balance. However changes in middle and low clouds drastically effect the balance, and are the most likely cause of the maximum radiation balance variability in the Gulf of Guinea region. This observed interannual variation of the top of the atmosphere net balance, reported in the present study, denotes the most variable ?cloud radiative forcing? situation observed to date.