In the past, the free-air gradient - 308.6 × 10^-8 s^-2 was used as the vertical gravity gradient of the measuring point in gravity data processing, which resulted in inaccurate instrument height corrections. To investigate the influence of using the vertical gravity gradient, theoretical gradients of the Jinzhai baseline field in the Dabie Mountains were calculated using DEM data and WGM2012 gravity anomaly data. Adjustment results were compared with those using the free-air gradient. Using the theoretically calculated vertical gravity gradient correction improved the scale factor calibration precision by an average of 0.00007. The average precision of gravity adjustment results under different datum controls increased from 2.23 × 10^-8 m/s² to 1.45 × 10^-8 m/s². In a single-datum control adjustment, the maximum effect of the actual vertical gravity gradient on datum transfer is 8.7 × 10^-8 m/s², while the effect without it is as low as 9.0 × 10^-8 m/s² and as high as 27.5 × 10^-8 m/s². In a multi-datum system, using the actual vertical gravity gradient yields the best results. Even with the three-datum control adjustment, the average effect of the free-air gradient correction on the results reaches 3.9 × 10^-8 m/s². Therefore, incorporating measured or theoretically calculated vertical gravity gradients into gravity data processing is essential for significantly enhancing its accuracy and precision.

Groundwater overexploitation in northern Henan Province has led to significant land subsidence and aquifer degradation. This methodologically driven study proposes a physically consistent framework that integrates Sentinel-1A-based Multi-Temporal Interferometric Synthetic Aperture Radar (MT-InSAR) data (2017-2022) with long-term groundwater head observations to invert elastic and inelastic skeletal storage coefficients and assess total groundwater storage (TGWS) changes. The framework is applied to the Anyang-Puyang Plain as a representative case study. MT-InSAR deformation time series were combined with Multi-channel Singular Spectrum Analysis (MSSA) decomposition and polynomial fitting to extract seasonal and long-term trends, enabling spatially distributed inversion of aquifer parameters. Results show strong spatial coupling between land subsidence and hydraulic head decline (maximum Pearson r is 0.993), with deformation dominated by inelastic compaction. The elastic storativity ranges from 0.00093 to 0.01596, whereas the inelastic storativity, ranging from 0.0362 to 0.0457 indicates irreversible compaction processes associated with a cumulative groundwater loss of approximately 3.01 × 10⁸ m³. Based on the long-term groundwater level observations collected in this study and the inferred assumption of preconsolidation head, the TGWS loss reached -12.27 × 10⁹ m³, with a mean annual rate of - 2.19 × 10⁹ m³/yr and pronounced depletion in northern areas. Standard deviational ellipse (SDE) analysis revealed a north-westward shift of the depletion centre and enhanced spatial clustering. These findings provide critical hydromechanical insights and quantitative constraints for future groundwater regulation and aquifer recovery strategies in overdrawn regions.