Unusual past dry and wet rainy seasons over Southern Africa and South America from a climate perspective

摘要: Southern Africa and South America have experienced recent extremes in dry wet rainy seasons which caused severe socio-economic damages. Selected past extreme events are here studied, to estimate how human activity has changed the risk of occurrence such events, by applying an event attribution approach (Stott et al., 2004)comprising global climate models Coupled Model Intercomparison Project 5 (CMIP5). Our assessment shows that models' representation mean precipitation variability over is not adequate make a robust statement about seasonal rainfall this region. Over Africa, we show unusually austral summers as occurred during 2002/2003 become more likely, whereas like 1999/2000 less likely due anthropogenic change. There some tentative evidence high 5-day totals (as observed 1999/2000) increased These results consistent with CMIP5 projecting general drying trend SAF December–January–February (DJF) but also increase atmospheric moisture availability feed heavy when they do occur. Bootstrapping confidence intervals fraction attributable demonstrated estimates very uncertain, if rare. The study highlights challenges making for using considering natural drivers ENSO coupled ocean–atmosphere models.