Monthly Scale Validation of Climate Models’ Outputs Against Gridded Data over South Africa

The validation of climate models is important for ensuring accurate climate variability over a given region. This study evaluates the performance of multiple global climate model simulations from the Coupled Model Intercomparison Project Phases 5 and 6 and the downscaled regional climate model simulations from the Coordinated Regional Climate Downscaling Experiment against gridded observational data from the Climatic Research Unit gridded data during the historic period 1981–2000. Spatial analysis using monthly bias maps and statistical metrics (i.e., correlation coefficient, standard deviation, and centred root-mean-squared error) were employed to assess the model outputs’ ability to reproduce monthly temperature and precipitation patterns over South Africa. The results indicate an improvement in CMIP6 and CORDEX model simulation outputs compared to their CMIP5 predecessors, with reduced biases and enhanced correlation. The study underscores the importance of model selection for regional climate analysis and highlights a need for further model development to capture complex physical processes.