Diurnal variability of regional cloud and clear-sky radiative parameters derived from GOES data. Part II: November 1978 cloud distributions ( Amazon Basin).

Abstract

Regional (250 x 250 km2) diurnal cloud variability is examined using mean hourly cloud amounts derived from November 1978 GOES-East visible and infrared data with a hybrid bispectral threshold technique. A wide variety of diurnal variations in cloud cover is presented. The largest diurnal cloud variations occur over the southeastern Pacific where low clouds are dominant. On the average, mean cloud fraction varied by about 0.35 in this area with a maximum near sunrise. Over the Amazon Basin, the vertical distribution of cloud cover follows a pronounced diurnal cycle which shows maximum high-cloud cover occurring in the late afternoon. A large-scale diurnally modulated circulation feature between the Amazon and the adjacent oceans is suggested.-from Authors