Investigating Key Climate Parameters over West Africa under RCP8.5 Scenario from RCA Multi Model Simulations

Rainfed agriculture is dominant in West Africa, and therefore dependents highly on climate conditions. To better assess the impacts of climate change on this central sector, regional studies and in-depth analyses of key climate parameters and/or indicators were conducted. In this study, we used data from the Coordinated Regional Downscaling Experiment (CORDEX-AFRICA) simulations to assess climate paramters that affect agricultural activities over West Africa. The Swedish Meteorological and Hydrological SMHI-RCA3.5 regional climate model, run at a 50km horizontal resolution for a domain covering the whole Africa, was assessed over West Africa for an historical period and the future under the Representative Concentrations Pathway 8.5, (RCP8.5). The yearly variations in temperature and especially the drought of the early 1980s are not well simulated by most models. While the seasonal cycle is reasonably well captured by a few models, these generally fail to simulate the onset of the rainy season. Under RCP8.5, models generally project slightly wetter conditions for both intermediate and far terms over the whole West Africa. Another finding, in keeping with current trends, is the positive trend slope of precipitation, which has a high coefficient of variation suggesting a swing pattern mainly over the Sahel for both the IT and the FT.