Estimation of regional evapotranspiration in the extended Salado Basin (Argentina) from satellite gravity measurements

Abstract

In this study, regional evapotranspiration is estimated in a wide flatland area that includes Salado River Basin and four tributary basins by using gravity measurements of the space mission Gravity Recovery and Climate Experiment (GRACE). Monthly estimates of large-scale variations in the land-water storage are obtained from the satellite data. Evapotranspiration is computed with the water-balance equation using the GRACE land-water solutions, rainfall data from the Global Precipitation Climatology Center and runoff values obtained as 5% of the precipitation. GRACE-derived evapotranspiration values are consistent with the different climatic scenarios observed, and they satisfactorily agree with estimates provided by a global hydrological model. The overall results show that the method used is a valid tool for characterizing the evapotranspiration in the Argentine Pampas and that it can be used to detect and examine changes in the evapotranspiration pattern associated with the occurrence of extreme climatic events. This study illustrates the ability of GRACE to analyze and predict evapotranspiration and other processes on a regional scale in a flatland area.