Identifying and separating climate- and human-driven water storage anomalies using GRACE satellite data

Abstract

Hydrological changes, which are affected by climate variability and human activities, pose challenges to the sustainable management and conservation of water resources. As such, it is important to improve our understanding of how climate and anthropogenic activities impact land water storage. Previous studies using Gravity Recovery and Climate Experiment (GRACE) satellite data have struggled to effectively separate the impacts of climate variability and human activities on water storage. Here, we propose a statistical model that simulates natural dynamically driven changes in water storage to reconstruct climate-driven water storage anomalies at basin scales and discuss the possibility of differentiating climate- and human-driven water storage anomalies. The prediction and reconstruction performance of this method shows optimal robustness. Compared with water storage anomalies calculated using land surface models, our reconstruction results are closer to GRACE observations, especially in humid basins with few human interventions. Mismatches are found in basins with intensive human interventions. Isolated human-driven water storage anomalies in four representative basins correlate well with anthropogenic water usage in each basin. The results of this study provide a method to effectively separate and monitor climate- and human-driven water storage anomalies, thereby providing information for better protection and utilization of water resources.