Global marine gravity field models at 1-arcminute resolution derived from optimized fusion of ICESat-2 along-track and cross-track measurements

Satellite altimetry is a primary source for deriving the global marine gravity field. Leveraging Ice, Cloud and Land Elevation Satellite-2 (ICESat-2) multi-beam laser altimetry, this study constructs global 1-arcminute gridded models of marine deflection of the vertical (DOV) and free-air gravity anomaly, referenced to the GRS80 ellipsoid. Because orbit inclination limits azimuthal sampling, the sparse cross-track geoid gradient coverage means the meridional component is generally more accurate than the prime-vertical component. ICESat-2's ATLAS (Advanced Topographic Laser Altimeter System) employs a multi-beam configuration that provides high-density along-track elevation measurements together with near-simultaneous cross-track sampling, enabling robust constraints on cross-track geoid gradient. To mitigate this anisotropy, we implement an optimized fusion that combines the meridional component estimated from along-track geoid gradients with the prime-vertical component estimated from cross-track geoid gradients, yielding a directionally balanced DOV model. This fusion improves component-wise accuracy and enhances the stability and overall accuracy of the gravity anomaly inversion. The resulting DOV and gravity anomaly models are rigorously evaluated.