Assessment of the CORDEX Regional Climate Models Performance in Simulating the Climate Conditions of Arsi Zone Southeastern Ethiopia

Evaluation of climate model skills in reproducing local-scale climate conditions is an important aspect of climate studies. This study aimed to assess the performance of five Regional Climate Models (RCMs) available in the Coordinated Regional Climate Downscaling Experiment (CORDEX). The assessment was based on how well the RCMs replicated rainfall, maximum and minimum temperatures, interannual and seasonal variations over southeastern Ethiopia during the simulation period of 1980-2005. The results indicated that the Regional Climate Models (RCMs) exhibited substantial bias in simulating annual rainfall cycles, particularly in higher elevation areas of the study region. The Regional Model (REMO2009) simulated the maximum temperature, while the Regional Atmosphere Climate Model (RACMO22T) better simulated the minimum temperature compared to other models. However, the ensemble of models performed better than the individual RCMs in simulating the annual cycle of temperature. The variation in rainfall was greater than the variation in temperature, both seasonally and interannually. RACMO22T and Climate Limited Area Modeling (CCLM4-8) showed better performance in capturing the cumulative distribution of rainfall events and return period. The Regional Atmospheric Model (RCA) was characterized by a significant overestimation of cumulative distribution and return period. The disparity in performance among the Regional Climate Models indicates their sensitivity to location and topography. Therefore, the selection of a suitable RCM for a specific location is essential for any climate-related and other definite articles study or local climate projections.