Improving understanding of spatiotemporal water storage changes over China based on multiple datasets

Abstract

Accurate estimation of water storage estimates is important for the reliable assessment of regional water resources and climate variability. The purpose of this study is to generate long-term and high-resolution water storage estimates based on the World-Wide Water (W3) model. Ten river basins over China are chosen as the study area, and the performance of W3-based simulations is evaluated against GLDAS and GRACE solutions. More importantly, W3-based simulations are employed to investigate the occurrence and spatiotemporal evolution of drought events in the Yangtze River Basin (YZRB) to evaluate the superiority of the W3 model. Results suggest that larger amplitude is mainly distributed in Southern China for soil moisture, which is ~ 3 times larger than that of snow water equivalent. The deficiencies in groundwater storage anomalies are highlighted for CLSM and W3 models although the correlation is at a high level (~0.54 on average) between these two simulations. Additionally, the W3-based terrestrial water storage anomalies (TWSA) are superior to other models in the Yellow River Basin (YRB) and YZRB against GRACE observations with the correlation coefficient (CC) and root mean squared error (RMSE) of (0.51, 40.24 mm) and (0.81, 27.08 mm), respectively. However, all models present poor performances in the Haihe River Basin (HRB) with the smallest CC (0.27 on average) and largest RMSE (113.29 mm on average). With respect to characterizing extreme events, the W3 model can accurately reflect the spatiotemporal evolution of the 2011 drought event against scPDSI and SPEI metrics. Specifically, TWSA experience severe deficit in the southern YZRB based on the W3 model, which is most consistent with two drought metrics and bulletin records. The Three-Cornered Hat method reveals that larger uncertainties in TWSA can be observed in the Southeast River Basin (SERB, 63.93 mm), YZRB (67.29 mm), Pearl River Basin (PRB, 73.52 mm), Southwest River Basin (SWRB, 68.62 mm), and the dominant uncertainty resulting from the soil moisture component. The water storage estimates generated in this study can lead to better understanding on regional water resources and provide reliable information to elaborate depictions of climate changes. Show more