Future changes in rainfall amounts at the Mosul station according to climate change scenarios (RCPs) using statistical miniaturization technique (SDSM)

Abstract

This research aims to analyze future rainfall patterns at the Mosul station by comparing baseline data (1991–2020) with projections for the period (2025–2050) under climate change scenarios RCP2.6, RCP4.5, and RCP8.5, using Statistical Minimization Symmetry (SDSM) based on CMIP5 model outputs. Monthly and annual rainfall averages, peak values, and variability were analyzed, along with the Standard Precipitation Index (SPI) to assess drought severity for the period (2025–2050). The results show a clear downward trend in rainfall, with annual averages decreasing by up to 26.7% in the RCP8.5 scenario by 2050, and a significant decline in peak rainfall months. Peak rainfall values also increased by approximately 27%, and variability rose by more than 30%, reflecting escalating climate instability. The SPI also showed a trend toward increasing drought severity, with its values decreasing to the low end of the range. (-2.0), indicating a very severe drought at the end of the period. The results suggest a shift in the rainfall pattern towards a more extreme pattern, characterized by decreased amounts, increased intensity, and irregularity, which raises the risks of drought and flooding and necessitates the adoption of effective water resource management strategies and climate change adaptation.