Separating the Precipitation‐ and Non‐Precipitation‐ Driven Water Storage Trends in China.

Terrestrial water storage (TWS) is a critical component for sustainable societal development and ecosystem cycles. The Gravity Recovery and Climate Experiment satellites have tracked changes in global TWS under the combined effects of various factors with unprecedented accuracy since 2002. In this study, we separate the trends in TWS driven by precipitation and non‐precipitation factors for the Chinese mainland from 2003 to 2016 based on the statistical reconstruction method and linear regression and analyze the driving mechanisms combining with multi‐source data. The results show that: (a) during the study period, TWS shows different degrees of increase in most of the Yangtze River basin, the northern part of the Tibetan Plateau, and part of the Heilongjiang Province, while TWS shows a significant decrease in the Tien Shan Mountains, the southeastern part of the Tibetan Plateau, and the North China Plain; (b) precipitation is one of the dominant factors leading to the rise of TWS, and the construction of reservoirs and dams also contributes. In contrast, anthropogenic activities (agricultural irrigation, industrial water use, etc.) and accelerated glacial melting due to global warming are the dominant factors in the decline of water storage; (c) the contribution of long‐term precipitation change to water storage is significantly larger in the northern China region (north of the 800 mm isopleth). This study provides a feasible method for quantifying the contribution of precipitation and non‐precipitation factors to TWS, which is meaningful for understanding the impact of climate change and anthropogenic factors on water resources. Plain Language Summary: Water scarcity is a global crisis for social development in the present and future. As the world's most populous country, China's per capita freshwater resources are far below the global average, making the imbalance between water supply and demand in China even more serious. The study of water storage changes contributes to understanding freshwater resources in China. Here, the precipitation‐ and non‐precipitation‐ driven water storage changes in China are separated based on the statistical reconstruction method and long‐term precipitation data. In addition, satellite gravity, model simulations, and in‐situ data are combined to analyze the driving mechanism in regions that experienced significant changes in water storage during the past decades. Human activities and glacier melting are the dominant factors leading to the water storage deficit. Both precipitation and dam construction contribute to the increase in water storage. This study would provide valuable information for the rational allocation of water resources and coordinated development of the economy and ecology. Key Points: Terrestrial water storage (TWS) trends induced by long‐term precipitation change, precipitation variability, and non‐precipitation factors are separated in ChinaThe TP‐TWS factor is proposed to characterize the impact of long‐term precipitation trends on the TWS trendsThe TWS changes in typical regions are rationalized from the perspective of precipitation and non‐precipitation factors [ABSTRACT FROM AUTHOR]