Local-Scale Validation of High-Degree Gravity Field Models in the Ordos Region

Xiaoping Ke¹Hua Chai^1*ZhiPeng Fan^1,2Zhengpeng Gan^1,2

• ¹Chinese Academy of Sciences Innovation Academy for Precision Measurement Science and Technology, Wuhan, China
• ²University of the Chinese Academy of Sciences, Beijing, China

High-degree global gravity field models have been widely applied in geodesy and geophysics, yet their accuracy and reliability in regions lacking terrestrial gravity data remain insufficiently assessed. To address this issue, this study uses two high-precision gravity survey profiles in the Mu Us region of northern China to comparatively evaluate three representative models: EGM2008, EIGEN-6C4, and SGG-UGM-2. The analysis focuses on their performance in representing gravity disturbance, free-air gravity anomaly, and Bouguer gravity anomaly at the local scale. Results show that along profiles 5000 and 6000, the standard deviations of the differences between model-derived and observed gravity disturbances are 2.679 – 2.825 mGal and 4.657 – 4.858 mGal, respectively. Although all three models capture the overall gravity trends, they exhibit clear limitations in resolving small-scale, high-frequency signals. Specifically, limited spatial resolution prevents accurate representation of short-wavelength topographic gravity signals, while in areas lacking ground data, reliance on terrain information alone cannot recover gravity effects from subsurface density anomalies. These findings show that although high-degree global gravity field models are effective for large-scale applications, their use in small-scale geophysical studies remains restricted. This study provides a useful reference for evaluating the regional suitability of high-resolution gravity field models.