Projected Changes in Meteorological Drought Over East Africa Inferred from Bias-Adjusted CMIP6 Models

Abstract The ongoing global warming has caused unprecedented changes in the climate system, leading to climate change and increase in drought occurrence, duration, severity and intensity. This research uses the sixth phase of Coupled Model Intercomparison Project (CMIP6) data to investigate the projected changes in drought events over East Africa (EA) under four Shared Socioeconomic Pathway (SSP) emission scenarios (SSP1-2.6, SSP2-4.5, SSP3-4.0 and SSP5-8.5). Drought is quantified using the standardized precipitation index (SPI) considering different measures: drought duration (DD), drought frequency (DF), drought severity (DS) and drought intensity (DI). The CMIP6 data are first bias-corrected using a quantile mapping method, with the Climatic Research Unit (CRU)’s precipitation data as the observation. Evaluating the accuracy and reliability of historical data before and after correction demonstrates the importance of such approach. The projection results show that a drying pattern is expected during the mid future, while the end of the century is projected to get wetter, with a stronger magnitude for the wetting than the drying trend. Moreover, the dry areas of EA are likely to experience more frequent drought events with longer duration and stronger intensity and severity in the far future. In contrast, the highland and lake regions are likely witness a decrease in drought occurrences, affirming the “dry gets drier and wet gets wetter” theory over EA. This study identifies possible drought hotspots over EA, thus enabling early preparation for such events.