Spatial-temporal characteristics of water storage in Africa based on GRACE and GLDAS data

United Nations Educational, Scientific and Cultural Organization (UNESCO) pointed out that about 300 million Africans live in poverty because of water scarcity. However, Africa does not lack natural water resources, but only makes insufficient use of them. We aim to understand the distribution of water storage in Africa and its changes for better management of these water resources. Based on the data from the GRACE gravity satellite and the GLDAS hydrological model, the changes in the total water storage (TWS), the surface water storage (SWS), and the groundwater storage (GWS) of Africa are calculated. On the hydrogeological base service platform OneGroundwater, we comprehensively analyzed the effects of rainfall, land use types, and other human activities on the water reserves. We found that the SWS decreases in the recent 15 years, which suggests that the utilization of surface water in Africa is significant. Meanwhile, the increase in the GWS indicates that the development of groundwater is not enough. Promoting the sustainable extraction of groundwater is helpful to the social development in Arica. Our analysis results show that rainfall is decisive for the changes in the GWS of Africa. The seasonal variation trend of the GWS is consistent with that of rainfall, while there is a certain lag in the yearly variations. The effects of land use types are mainly reflected in recharge and evaporation. The increase in vegetation density strengthens transpiration and reduces the recharge rate of groundwater.