Global marine full-tensor gravity gradients constructed by a differential method

Gravity gradients are important for underwater navigation, seafloor topography inversion, and submarine geological investigation. In this study, a global marine full-tensor gravity gradient model, named GMGGD1, is derived using a differential method based on deflection of the vertical and gravity anomaly products incorporating Surface Water and Ocean Topography (SWOT) satellite altimetry observations. The reliability and consistency of GMGGD1, and the contribution of SWOT data are evaluated through comparisons with existing gravity-gradient products and ultra-high-degree gravity field models. The mean and standard deviation (STD) of the differences between the vertical gravity gradient component of GMGGD1 and SIO curv_SWOT_03 are approximately 0.05 E and 1.47 E, respectively. Comparisons with SGG-UGM-2 show that the absolute mean differences of all components are smaller than 0.01 E, with STDs below 8.0 E, and larger differences occur mainly in regions with sharp seafloor topographic variations, such as trenches and seamount chains. Further comparisons with CUGB2023GRAD, GMGG1, and GMGGD-V32 indicate that GMGGD1 shows good overall consistency while exhibiting stronger short-wavelength signals. In particular, compared to GMGGD-V32, which was derived without using SWOT observations, GMGGD1 displays significantly stronger signals at wavelength shorter than 20 km, highlighting the contribution of SWOT observations.