Global seafloor topography model based on a frequency-domain filter combination method

Seafloor topography is fundamental in a wide range of oceanographic and geophysical studies. Using a novel frequency-domain filter combination method, we developed a global seafloor topography model, hereafter SYSU_FGGM, in which short-wavelength components (<65 km) were reconstructed using the Gravity-Geologic Method (GGM) and SWOT_02 gravity anomalies, and long-wavelength components (>65 km) were derived from the topo_25.1 model. Shipborne single-beam and multi-beam bathymetric data provided by the National Centers for Environmental Information (NCEI) and GEBCO_2024, respectively, were used to assess accuracy. The SYSU_FGGM model outperformed the 1′ × 1′ spatial resolution topo_25.1, DTU21, and SDUST2023BCO models, reducing the standard deviation of the depth differences (calculated relative to the single-beam data) by 13.0 m, 20.4 m, and 3.0 m, respectively. Based on external accuracy assessments against multi-beam grids, SYSU_FGGM achieved superior or comparable performance, relative to the existing models, for representative areas of the western Pacific, central North Atlantic, and polar regions. SYSU_FGGM effectively leverages the advantages of GGM modeling in reconstructing short-wavelength topography, while mitigating its limitations in long-wavelength modeling. This novel frequency-domain filter combination approach significantly enhances the accuracy and spatial consistency of global seafloor topography estimation.