Using an Iterative Algorithm to Predict Topography From Vertical Gravity Gradients and Ship Soundings

• Published in: Earth and space science (Hoboken, N.J.) N.J.), 2022-10, Vol.9 (10), p.n/a
• Main Authors: Xu, Huan, Yu, Jinhai
• Format: Article
• Language: English
• Subjects: Accuracy; Algorithms; error resistance analysis; Gravity; iterative computation; Ocean floor; Sea level; Topography; vertical gravity gradient
• ISSN: 2333-5084; 2333-5084
• DOI: 10.1029/2022EA002437

With the help of the analytical expression of the vertical gravity gradient (VGG) generated by a rectangular prism, an analytical algorithm for predicting seafloor topography using the VGG data has been studied. Nevertheless, ship sounding data are an essential constraint in solving the seafloor topography. This paper combines ship sounding data with VGG anomaly to predict the seafloor topography. The main research contents include the following: Using the ship soundings and VGG data in the study area, the observation equations about sea depth are established, and the stability of the equations are studied; furthermore, considering the influence of seafloor topography outside the study area on the observation equations, these effects are divided into boundary effects and far‐field effects, and different processing methods are proposed. Finally, the method is tested on the East Pacific Rise, only using VGG anomaly and adding the mean value to fix the boundary region, the RMS error of the results is 108.8 m; SIO's model is added to the boundary region and the seven maximum absolute errors are replaced by ship sounding data, the RMS error of the results can reach 94.2 m and the accuracy improvement is 13.42%. Plain Language Summary The topographic fluctuation can be composed of many different rectangular cylinders, and the vertical gravity gradient generated by a rectangular cylinder on the sea level has an analytical expression. In this paper, the observation equations are established by using this analytical expression to predict the seafloor topography, and different methods are studied to control or weaken the influence of boundary effects and far‐field effects. This study will provide a new idea for the refinement of seafloor topography in the future. Key Points A new method for predicting seafloor topography from vertical gravity gradient and ship soundings, and the effectiveness of the algorithm is verified by numerical simulation The sources of interference errors are refined as “boundary effects” and “far‐field effects,” and different processing methods are proposed; the algorithm is applied to the test area and the RMS error of prediction results can reach 94.2 m