Enhancing uncertainty of regional climate models for climate change projection at Western Nile Delta

Abstract

ABSTRACT The objective of this research is to refine the precision of uncertainty estimates associated with Regional Climate Models (RCMs) for precipitation forecasts in the Western Nile Delta region of Egypt up to the year 2100. This refinement is predicated upon a comprehensive evaluation of the performance of selected models. The study employed two RCMs, specifically RCA4 and RACMO22, which integrated outputs from three distinct Global Circulation Models (GCMs): ICHEC-EC-EARTH, CCCma-CanESM2, and MPI-M-MPI-ESM-LR, each characterized by different resolutions. To assess the performance of these models, a suite of statistical metrics was utilized, including the Percentage of Bias, Root Mean Square Error (RMSE), and Nash-Sutcliffe Efficiency Coefficient. The evaluative process encompassed an analysis of precipitation patterns across three strategically selected locales within the study area: Alexandria, Borg-Al-Arab, and Wadi El-Natroun. The resultant performance indicators were within deemed acceptable limits, evidencing RMSE values up to 6.91, Percentage of Bias not exceeding 0.33, and Nash-Sutcliffe Efficiency Coefficients up to 0.78. The analysis elucidated that among the models scrutinized, the RCA4 model, when driven by output from the ICHEC-EC-EARTH-SMHI GCM, demonstrated superior performance, thereby underscoring its efficacy for detailed precipitation projection in the context of the Western Nile Delta.