SYSU_FGGM: the new global seafloor topography model using filter combination method

We develop a new global bathymetric model, named SYSU_FGGM, spanning from 80°S to 80°N with a grid resolution of 1′×1′. The model employs a filter combination method with a cutoff wavelength of 65 km, using the topo_25.1 model as the baseline topography for long-wavelength components (≥65 km). Short-wavelength components (<65 km) are reconstructed using the Gravity-Geologic Method (GGM) and the SWOT_02 gravity anomaly model released by the Scripps Institution of Oceanography (SIO). To ensure high accuracy in shallow and coastal regions, bathymetric data from topo_25.1 are retained for water depths shallower than 300 m