The Modulation of Daily Southern Africa Precipitation by El Niño–Southern Oscillation across the Summertime Wet Season

Abstract The spatiotemporal evolution of daily southern Africa precipitation characteristics, and associated atmospheric circulation, related to El Niño La Niña is examined across the region’s November–April wet season. Precipitation characteristics are in terms monthly changes average precipitation, number days, heavy days three independently constructed estimates observed during 1983–2018. Mechanisms changes, including contributions from mass divergence, water vapor transports, transient eddies, diagnosed using moisture budget based on ERA5 reanalysis. anomalies that build December–March, core rainy season, culminating significantly below values stretching a semiarid region central Mozambique southeastern Angola. A broad anticyclone centered over Botswana drives these primarily through anomalous with advection eddies playing secondary roles. above all south 20°S February much less so other five months. driven divergence due strong cyclonic whereas similar circulation more diffuse evolutions not equal opposite. robustness an asymmetric evolution, which could have implications for subseasonal forecasts, needs be confirmed analysis additional empirical data established climate model experimentation.