Assessment of terrestrial water storage variations and spatial heterogeneity across the Pearl River Basin: the influences of climatic change and human activities

Understanding the temporal and spatial distribution of terrestrial water storage anomalies (TWSA) is essential for comprehensive regional water resource management. In this study, an integrated seasonal TWS quantitative analysis model was proposed to reflect the spatiotemporal variability of TWSA and reveal the driving mechanisms of climate change and human activities on TWSA through a combination of the seasonal Kendall test, Pearson correlation analysis, and the optimal parameters-based geographical detector. The Pearl River Basin, as a significant region for more efforts to conserve water resources system safety in China, was taken as a case study area. Five key factors from climate change and human activities were selected. Temporal and spatial variations of TWSA, five impact factors, evolution analysis, and contribution quantification of different factors on TWSA results were obtained through the proposed model. The results indicated that TWSA had increased significantly with a rate of 5.63 ± 1.22 mm/a in PRB during 2003–2017, accompanied by a strong spatial heterogeneity. Climate change and human activities had significant differences in the single effect on TWSA under different seasons; the interaction between human activities and climate change would intensify the influence on TWSA.