Cloud Radiative Forcing in Pacific, African, and Atlantic Tropical Convective Regions

Abstract

Abstract The high degree of cancellation between longwave (LW) and shortwave (SW) cloud radiative forcing (CRF) observed in the Pacific warm pool region has generally been assumed to be a property of all convective regions in the Tropics. Analysis of the (Earth Radiation Budget Experiment) ERBE-like data from the Clouds and the Earth's Radiant Energy System (CERES) instrument on the Terra satellite reveals that a similar degree of cancellation occurs over the African convective region at monthly and longer time scales, but only in the area average. In the Atlantic intertropical convergence zone (ITCZ), the degree of cancellation is lower, particularly during the summer months, where the area-average SW forcing typically exceeds the LW forcing by more than 20 W m−2. This behavior is similar to that found previously for the eastern Pacific ITCZ region, which is consistent with the similarity in dynamics between these two regions. Over Africa, substantial seasonal and spatial variations in net CRF occur, wit...