Evaluation of groundwater storage variability and relationship with hydrometeorological factors in the Huang-Huai-Hai Plain, China, using GRACE and GLDAS Data (2002–2023)

Huang-Huai-Hai plain, China. In this study, we analyzed groundwater storage anomalies (GWSA) in Huang-Huai-Hai plain from 2002 to 2023 using Gravity Recovery and Climate Experiment (GRACE), Global Land Data Assimilation System (GLDAS), and observed groundwater depth data, focusing on interannual, seasonal, and spatial variations, and the impact of hydrometeorological factors The seasonal Mann-Kendall test and change point detection identified three GWSA phases: slow growth (0.93 mm/a), decline (-15.69 mm/a), and recovery (22.81 mm/a). Pearson correlation showed stronger GWSA-observed groundwater depth data relationships in the northwest. Partial correlation analysis indicated that evapotranspiration and surface runoff negatively correlated with GWSA, while precipitation and temperature positively correlated. The feature importance based on the random forest revealed that, between April 2002 and September 2023, temperature had a slightly greater influence on GWSA variations than other factors, followed by precipitation, evapotranspiration, and surface runoff. • Groundwater storage variations (interannual, seasonal, spatial) in the Huang-Huai-Hai Plain over 22 years are analyzed. • The key periods and trends in groundwater storage over the study period are detected. • The influence of hydrometeorological factors on GWSA changes is quantified.