Hydrological Mass Variations in Major River Basins in China with the Use of GRACE Monthly Gravity Field Models

Abstract

Mass redistributions within the Earth system induce changes in the planet's gravity field, observable via the Gravity Recovery and Climate Experiment (GRACE) mission. GRACE data have become essential for monitoring large-scale hydrological processes. While GRACE captures water mass variations at the basin scale, in situ hydrological stations provide localized insights based on water level and volume changes. This study investigates water mass variations across the major river basins of mainland China, aiming to link basin-scale GRACE observations with local in situ measurements. Building on previous findings from the La Plata River basin, this research explores the potential phase lag between GRACE-derived mass changes and tide gauge records. However, no significant phase lag was identified in Chinese basins, likely due to intensive water management practices that also affect subsurface water storage. Nevertheless, the GRACE-derived sur-face mass variations were validated, showing strong temporal and spatial agreement with simulated total water storage anomalies from the CLHMS model and ERA5-Land reanalysis.