Variation and Attribution of Terrestrial Water Storage in the Yangtze River Basin

Objectives: Climate variability and human activity have profoundly altered the terrestrial water storage in the Yangtze River basin, significantly threatening the social economy, ecological environment, and food safety of China. However, the variations and attributions of the terrestrial water storage in the basin has not been comprehensively analyzed. Methods: This study jointly used the GRACE solutions, field observations, statistical model, and large-scale hydrological simulation to perform the attribution of terrestrial water storage anomaly (TWSA) variations in the Yangtze River basin during 2002-2021. Results: The results show:(1) the relative uncertainties of GRACE mascon product from CSR, JPL, and GSFC reaches 5, 7.2, and 3.9 mm, respectively; (2) the merged GRACE product from three institutions based on relative uncertainties present reasonable accuracy by comparing with the in-situ results and water resources bulletins, with the correlation coefficient of 0.59 and 0.86 (P<0.01), respectively; (3) Similar partition results are reflected by the statistical and hydrological modeling results, in which the TWSA is mainly controlled by precipitation, while the human factors such as reservoir impoundment and agricultural irrigation can significantly affect the TWSA at the local scale. Conclusions: The historical TWSA of the Yangtze River basin has been altered extensively by climate variability and human activity based on the partitioned merged GRACE solution.