Comparison of multimodel ensembles of global and regional climate models projections for extreme precipitation over four major river basins in southern Africa— assessment of the historical simulations

Abstract This study assesses the performance of large ensembles global (CMIP5, CMIP6) and regional (CORDEX, CORE) climate models in simulating extreme precipitation over four major river basins (Limpopo, Okavango, Orange, Zambezi) southern Africa during period 1983–2005. The ability model to simulate seasonal indices is assessed using three high-resolution satellite-based datasets. results show that all overestimate annual cycle mean basins, although intermodel spread large, with CORDEX being closest observed values. Generally, interannual variability rainy days (RR1), maximum consecutive wet (CWD), heavy very (R10mm R20mm, respectively) seasons. Simple daily rainfall intensity (SDII) number dry (CDD) are generally underestimated. lowest Taylor skill scores (TSS) spatial correlation coefficients (SCC) depicted for CDD Limpopo compared other respectively. Additionally, exhibit highest normalized standard deviations (NSD) CWD indices. RCM lower better, respectively, than those GCM (except CDD). In particular, performs better CORE basins. Although ensemble biases often within range observations, statistically significant shown by underline need bias correction when these impact assessments.