Quantifying mass signatures of drought and flood events using water fluxes and terrestrial water storage anomalies

The Gravity Recovery and Climate Experiment (GRACE) and its follow-on mission (GRACE-FO) have been providing spaceborne observations of terrestrial water storage (TWS) changes since 2002. These observations help to understand how water fluxes change in an intensifying water cycle at watershed scales. However, the accuracy of the derived TWS anomalies depends on the choice of spatial and spectral filtering methods, which can attenuate their amplitude.

In this poster, we present our filter-free inversion scheme that estimates TWS anomalies at watershed scales from Level-2 Stokes coefficients together with their associated full error covariance matrices. We apply the scheme to the watersheds in the Greater Horn of Africa and compare the obtained TWS anomalies with the accumulated watershed-wide precipitation and evapotranspiration fluxes from the ERA5 atmospheric reanalysis, and the accumulated river discharge from GLOFAS and GEOGLOWS products. We further assess the consistency between the temporal derivatives of TWS anomalies and the corresponding water fluxes. Additionally, we quantify mass deficits and surpluses in TWS anomalies and investigate the relative contributions of atmospheric net flux (i.e., precipitation minus evapotranspiration) and river discharge to the magnitude of TWS anomalies during drought and flood events.