Impact of Internal Climate Variability on Future Changes in Southern African Precipitation

Abstract: Variations in southern African precipitation have strong effects on local communities, increasing climate-related risks, increasing the severity and intensity of droughts and flooding, and impacting hydroelectric production and natural ecosystems. However, future changes in southern African precipitation are uncertain, with climate models showing a large range of responses from near-future projections (2020-2040) to the end of the 21st century (2080-2100). We assess uncertainty in southern African precipitation change using 5 Ocean-Atmosphere General Circulation single model initial-condition large ensembles (SMILEs; 30 to 50 ensemble members) and four emission scenarios. We show that the main source of uncertainty is the internal climate variability for southern African precipitation across the 21st century. We show that differences between ensemble members in simulating the future changes in the location of the Angola Low and of the large-scale anomalies in atmospheric circulation over the Pacific Ocean (ENSO-related changes) explain a large proportion (~64%) of the precipitation change uncertainty. 

Biography: I am a Senior Research Scientist at the National Centre for Atmospheric Science and the University of Reading. I have experience in tropical climate, particularly in quantifying the effects of external forcing and climate variability on precipitation across Africa. My current work on tropical climate is on understanding uncertainty in simulations of future changes in precipitation and atmospheric circulation, with a focus on West and Southern Africa. I also work on decadal climate variability and predictability, with a particular interest in the North Atlantic.