Spatial-temporal variations of groundwater storage in China: A multiscale analysis based on GRACE data

Groundwater storage (GWS) plays a key role in the freshwater supply in China. Revealing the changes in GWS in China is critical for realizing sustainable utilization of groundwater resources. We used Gravity Recovery and Climate Experiment (GRACE) satellite data as well as HydroSHEDS datasets to quantify the variation of GWS in China from 2003 to 2020 at multiple scales. We found that GWS was decreasing at a rate of -2.09 mm/a in China. Three hot-spot areas with dramatic GWS decrease, located in Northwest, Southwest and North China, accounted for 55.52% of the total GWS decrease in China, and the reduction in GWS in these areas was driven primarily by human activities. Additionally, more than half of the urban agglomerations in China potentially impacted by the declining GWS. Therefore, it is suggested that targeted measures should be taken according to local conditions to strengthen the scientific management of groundwater.