Projections of Future Droughts in Morocco: Key Insights from Bias-Corrected Med-CORDEX Simulations in the Haouz Region

Drought is one of the major challenges hindering development in semi-arid regions particularly in developping countries. Hence, this study aims to predict future climatic drought in the Haouz region of Morocco. Seven grid points of the ERA5 data were used to evaluate three regional climate models from Med-CORDEX and seven statistical bias correction techniques from the Climate Model data for hydrologic modelling of the Soil and Water Assessment Tool, using Percentage Bias values, Root Mean Square Error, correlation coefficient, and Taylor Skill Scores. For precipitation, the CNRM model corrected by the Power Transformation (PT) method proves to be the most accurate at low altitudes. At intermediate altitudes, the combination of the HadGEM model with the PT method is more adequate. Regarding maximum temperatures, the Variance Scaling (VS) and Distribution Mapping (DM) corrections applied to the CNRM and CMCC models, respectively, offer the best performance. For minimum temperatures, the CMCC-VS pair is more performant. Following these observations, a general trend towards decreasing precipitation and increasing maximum and minimum temperatures is recognized, exacerbated by altitude and RCP8.5 scenario. Trends in drought indices reveal an intensification of future climatic droughts, especially under RCP8.5 scenario. In the short term, extreme episodes occur for intermediate altitudes, particularly under RCP8.5 scenario, while for low-lying areas, an increase in moisture is noted under RCP4.5 scenario. In the mid term, an increased prevalence of mild droughts under both scenarios is noted. Over the long term, greenhouse gas emissions are amplifying severe droughts with RCP 8.5, showing a progressive worsening of climate change.