Improving the Accuracy of Seafloor Topography Inversion Based on a Variable Density and Topography Constraint Combined Modification Method

The use of satellite altimetry to recover marine gravity anomalies allows for the rapid acquisition of seafloor topography on a wide range of regional scales. Currently, the commonly used approaches for inverting seafloor topography have been focused on the linear correlation between gravity anomalies and seafloor topography and have disregarded the effect of density contrast between the crust and seawater on depth. Therefore, we proposed a variable density and topography constraint combined modification (VDTCCM) method by deriving Parker’s formula and the Bouguer plate formula by introducing variable density and topography factors. This method can effectively recover topography-related nonlinear terms of gravity anomalies. Subsequently, the seafloor topography of the South China Sea was estimated by applying the VDTCCM method and was defined as Seafloor topography one (ST1), and following, the accuracy was evaluated using shipborne sounding data (SSD). The results indicate that the ST1 model’s SSD-checked accuracy is 23.34% and 39.42% higher than the common international models of ETOPO1 and DTU10, respectively. Moreover, the ST1 model has advantages in mapping rugged areas, showing more detailed topographical features. Consequently, the VDTCCM method can provide beneficial references for the construction of seafloor topography models on a large regional scale using gravity anomalies recovered from satellite altimetry.