Hydrological evaluation of the convection-permitting regional climate model RegIPSL in Morocco

Water resources in mountainous regions are affected by climate change, necessitating accurate hydrological simulations to provide plausible future scenarios for effective management. This study evaluates the added value of a high-resolution regional climate model (RCM) for projecting water resources under future climate scenarios. The RegIPSL regional Earth system model, was employed to simulate the European South-West (SWE3) domain at convection-permitting scale with a horizontal resolution of 3 km. Precipitation and temperature outputs were compared to those simulated by the model with a 20 km horizontal resolution. The model simulations are available for different 10-year time periods: an evaluation period (2000-2009), a historical period (1996-2005), and a future period with the rcp8.5 scenario (2041-2050). Bias correction was applied to model outputs, using the CDF-t method with in-situ observations and satellite-based data. The corrected datasets were used to force the HYPE and CemaNeige-GR4J  hydrological models, simulating river flows in 16 river basins located in the different mountainous regions of Morocco. Result indicated that the high-resolution model significantly enhanced the simulation of hydrological variables in the different basins. The range of different basins considered allowed to characterize the model's efficiency in different aridity and topographic contexts, using hydrological signatures for each basin to analyze past performance and explore future scenarios. This research underscores the added value of convection-permitting models in advancing hydrological impact studies for complex terrains.