New perspectives on land-atmosphere feedbacks from the African Monsoon Multidisciplinary Analysis (AMMA)

Research into land-atmosphere coupling within AMMA has highlighted the atmospheric impact of soil moisture on space scales of 5 km upwards and time scales of several days. Observational and modelling studies have shown how antecedent rainfall patterns affect new storms in the Sahel. The land feedback operates through various mechanisms, including a direct link to afternoon storm initiation from surface-induced mesoscale circulations, and indirectly via large-scale moisture transport in the nocturnal monsoon. The results suggest potential for significant improvements in weather forecasting through assimilation of satellite data. Intriguing questions remain about the importance of vegetation memory on seasonal-interannual scales.