Recent observed and simulated changes in precipitation over Africa

Multiple observational data sets and atmosphere-only simulations from the Coupled Model Intercomparison Project Phase 5 are analyzed to characterize recent rainfall variability and trends over Africa focusing on 1983–2010. Data sets exhibiting spurious variability, linked in part to a reduction in rain gauge density, were identified. The remaining observations display coherent increases in annual Sahel rainfall (29 to 43mmyr 1 per decade), decreases in March–May East African rainfall ( 14 to 65mmyr 1 per decade), and increases in annual Southern Africa rainfall (32 to 41mmyr 1 per decade). However, Central Africa annual rainfall trends vary in sign ( 10 to +39mmyr 1 per decade). For Southern Africa, observed and sea surface temperature (SST)-forced model simulated rainfall variability are significantly correlated (r~0.5) and linked to SST patterns associated with recent strengthening of the Pacific Walker circulation.