Observing the recent floods and drought in the Lake Victoria Basin using Earth observations and hydrological anomalies

The Lake Victoria Basin, home of Africa's largest freshwater lake, experienced extensive floods in 2019-2020 and anomalous drought conditions in early 2022. Both antithetical hydrological events raised concerns for an estimated 35 million people within the basin who are vulnerable to these continually recurrent hydrometeorological extremes. While there is a need for high -resolution spatial and temporal hydrological monitoring, in-situ observations are limited and insufficient within the basin. This study assesses the capability of publicly available Earth ob-servations and models to capture the occurrence of recent hydrological extremes within the Lake Victoria Basin. Spatial and temporal comparisons of the following hydrological variables are conducted within the Lake Victoria Basin from June 2002 - June 2022: precipitation, evapo-transpiration, runoff, soil moisture, lake height, and total water storage anomaly (TWSA). Results from the time series and spatial analyses confirm that the anomalous wet and dry events respectively occurred from October 2019 - March 2020 and November 2021 - March 2021. The observations also indicated a quick recovery from the drought event by June 2022. Additionally, a comparison of 9-km soil moisture and 1-km downscaled near-surface soil moisture products improves understanding of wetness spatial variability within the basin. These results were vali-dated using in-situ soil moisture data available through the International Soil Moisture Network, making this the first study to validate the downscaled 1-km soil moil moisture product within the African continent. Methods from this study demonstrate the utility of a diverse array of publicly available Earth observation and model data to improve understanding of recent hydrological anomalies and extreme events within the Lake Victoria Basin. This can be applied to water re-sources management, particularly in regions lacking sufficient in-situ hydrological data.