Unveiling evolutionary patterns, differentiation mechanisms, and driving pathways of groundwater storage anomalies in China’s Yellow River Basin

Study region: The Yellow River Basin(YRB), situated in north‑central China, serves as a crucial economic development zone and ecological security barrier, and the region’s groundwater security is confronted with severe threats and challenges. Study focus: Groundwater Storage Anomaly (GWSA) in the YRB from 2002 to 2023 was calculated using GRACE and GLDAS datasets. Spatiotemporal variation characteristics of GWSA were analyzed using statistical analysis, Theil-Sen median trend analysis, and Mann- Kendall trend tests. The spatial differentiation mechanisms were examined using the GeoDetector method. Structural equation modeling (SEM) was subsequently employed to investigate the driving pathways and directional effects influencing GWSA New hydrological insights for the region. GWSA exhibited significant spatiotemporal heterogeneity. Monthly dynamics showed unimodal seasonal fluctuations with minima in June-July and maxima persisting January-December. A sustained annual depletion trend revealed 414 % reduction (2002–2023). Spatially, GWSA displayed a west-to-east declining gradient intensifying downstream. Upstream variations were predominantly controlled by natural factors (topography, climate; all q > 0.1), downstream dynamics by socioeconomic drivers (Agricultural Irrigation, GDP; both q > 0.4), while midstream regions showed no dominant controls (all q < 0.1). Factor interactions demonstrated terrain-mediated multifactorial coupling upstream versus natural-socioeconomic synergies downstream. Structural equation modeling confirmed persistent GWSA suppression by socioeconomic factors (all path coefficients < 0), while natural drivers (climate, vegetation) exhibited region-specific influences.