Decadal variability in long- and short-lived hydrological extremes in Sub-Saharan Africa

Sub-Saharan Africa is affected by a high-level of temporal and spatial variability in climate, with large impacts on water resources, human lives and economies, notably through hydrological extremes, such as floods and droughts. Using a newly reconstructed 65-year daily streamflow dataset of over 600 stations distributed throughout sub-Saharan Africa, we first highlight that the frequency, intensity and duration of hydrological extremes are strongly impacted by decadal to multi-decadal variations. However, the key factors driving such decadal to multi-decadal variability remain poorly documented and understood. Thus, here, compiling information on local-scale drivers (precipitation, temperature, soil moisture) and large-scale drivers (sea-surface temperature modes of variability, such ENSO and AMO, in the different ocean basins), using relative importance analysis and multiple datasets (ERSSTv3, ERA5-land, REGEN), we investigate the respective contribution of large-scale versus regional-scale processes in driving decadal to multi-decadal variability in long-lived and short-lived flood and drought.