Investigating the response of the Botswana High to El Niño Southern Oscillation using a variable resolution global climate model

The Botswana High is an important component of the regional atmospheric circulation during austral spring, summer and autumn. While high tends to be stronger El Niño weaker La Niña, its direct response Southern Oscillation (ENSO) remains unknown. To that end, a variable resolution global climate model (Model Prediction Across Scales version 7, hereafter MPAS) applied with relatively (48-km grid spacing) over Africa coarser (240-km rest globe for study period 1980–2010. first experiment uses observed sea surface temperatures (SSTs) everywhere period, while second SSTs except Pacific Ocean, where monthly climatological are imposed. results were validated against satellite data (Global Precipitation Climatology Project, GPCP) reanalysis datasets (Climate Forecast System Reanalysis, CFSR; European Centre Medium-Range Weather Forecasts 5, ERA5). show MPAS gives credible simulation temporal variability High, seasonal rainfall 500-hPa geopotential heights Africa. In absence ENSO forcing, amplitude reduces but signal remains. Hence, this shows enhances strength does not aid in formation high.