Incorporating Sediment Effects Into Seafloor Topographic Inversion via Coefficient-Constrained Multivariate Regression

Currently, research on seafloor topographic inversion primarily focuses on various gravity data and inversion methods, while little attention has been given to the seafloor sediment effects. Additionally, there is ongoing controversy regarding the extent to which sediment effects influence the seafloor topographic inversion. To address these, we first apply Parker’s method to estimate the sediment gravity anomalies (GAs) using sediment thickness data, thereby resolving the difficulty of directly inputting sediment thickness into the inversion. In previous regression methods, the coefficient factors, when treated as outputs, significantly deviated from theoretical value. Therefore, we then propose the coefficient-constrained multivariate regression (MR-CC) method. By constraining the output range of the coefficient factors, we investigates the contribution of incorporating sediment effects to improving the accuracy of the coefficient factors and enhancing the effectiveness of seafloor topographic inversion. The accuracy of the seafloor topography models was evaluated over the study area located in the Sea of Japan. The results show that, compared to the linear regression (LR) model, the MR-CC series models, which consider the sediment contributions, improves RMS by 19.54% and MAPE by 26.27%, effectively enhancing the regression and inversion accuracy. Furthermore, we evaluated the impact of various sediment thickness ranges on the inversion accuracy and concluded that the sediment thickness data within the range of 0-4000 m offer higher accuracy, making them more suitable for seafloor topographic inversion. Finally, we employ the Convolutional Neural Network (CNN) to fuse sediment thickness and sediment GAs separately, demonstrating the effectiveness of data preprocessing in mitigating feature dependency in artificial intelligence (AI) applications, which further clarifies the previous controversies on sediment effects in seafloor topographic inversion.