Solar radiation estimation in West Africa: impact of dust conditions during 2021 dry season

Abstract. The anticipated increase in solar energy production in West Africa requires high-quality solar radiation estimates, which is affected by meteorological conditions and in particular the presence of desert dust aerosols. This study examines the impact of incorporating desert dust into solar radiation and surface temperature estimations. The research focuses on a case study of a dust event in March 2021, which is characteristic of the dry season in West Africa. Significant desert aerosol emissions at the Bodélé depression are associated with a Harmattan flow that transports the plume westwards. Simulations of this dust event were conducted using the WRF meteorological model alone, as well as coupled with the CHIMERE chemistry-transport model, using three different datasets for the dust aerosol initial and boundary conditions (CAMS, GOCART, MERRA2). Results show that considering desert dust reduces estimation errors in global horizontal irradiance (GHI) by about 75 %. The dust plume caused an average 18 % reduction in surface solar radiation during the event. Additionally, the simulations indicated a positive bias in aerosol optical depth (AOD) and PM10 surface concentrations. The choice of dataset for initial and boundary conditions minimally influenced GHI, surface temperature, and AOD estimates, whereas PM10 concentrations and aerosol size distribution were significantly affected. This study underscores the importance of incorporating dust aerosols into solar forecasting for better accuracy.