An Evaluation of Satellite Cloud Retrievals in Tropical West Africa

The radiation budget of tropical West Africa (TWA) is important for understanding the evolution of the west African monsoon, which plays a crucial role in the water cycle of west Africa. Yet the frequency, diurnal cycle, and radiative effect of clouds in this region remain poorly understood. A lack of continuous surface observations and existing field campaigns in this region means that our understanding of clouds is particularly reliant on satellite products, but this lack of observations also hinders efforts to evaluate and understand satellite cloud product performance.

Extensive observations taken during the recent DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa) field campaign provide a vital new opportunity to evaluate satellite cloud products in TWA. Both surface and aircraft observations from this field campaign are used in combination with detailed case studies and statistical analysis to provide a holistic view of the performance of satellite cloud products. We focus on cloud products based upon measurements from the SEVIRI (Spinning Enhanced Visible InfraRed Imager) series of instruments, which, due to their geostationary orbit, have the advantage of providing high temporal resolution cloud observations of TWA. An improved understanding of satellite cloud product errors and uncertainties in TWA is vital to ensure that existing cloud products are used appropriately and to inform development of future satellite observations. This in turn will facilitate an improved understanding of regional clouds radiative effects and their impact on the monsoon circulation.