In this study, we examine the potential influence of aerosols on the diurnal cycle of precipitation over Central Africa by analysing 5-year simulations performed with the version 4.4 of the Abdus Salam International Centre of Theoretical Physics model (RegCM4.4). Two sets of 6 years from January 2001 to December 2006 were simulated at a 40-km horizontal grid with 1 year for spin-up. Overall, our results indicate that the simulated seasonal aerosol loads are underestimated everywhere over the

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... dy domain compared to MODIS total aerosol optical depth retrieval, except the northern part encompassing Sahel region characterized by an occurrence of dust aerosols loading coming from the Sahelian region in West Africa. The model diurnal precipitation was evaluated against the TRMM 3B42 rainfall product. The diurnal evolution of precipitation reveals that the model represents the general pattern, but always with very low values peculiarly in the late afternoon. Over the rainy area, amplitude of precipitation is systematically affected by either a reduction or an increase by up to ± 20% and ± 40% during DJF and JAS, respectively. Scattering and absorption of solar radiation by aerosols can explain the reduction in diurnal amplitude of precipitation. The time of maximum precipitation is not really affected during both seasons over the major part of rainy area.