NSOAS24: a new global marine gravity model derived from multi-satellite sea surface slopes

作者：Shengjun Zhang, Xu Chen, Runsheng Zhou, Yongjun Jia · 发表于：Geoscientific model development · 年份：2025 · DOI：10.5194/gmd-18-1221-2025 · 被引用次数：4 · 研究领域：Geophysics and Gravity Measurements、Geomagnetism and Paleomagnetism Studies、Solar and Space Plasma Dynamics

Abstract. Judging by the early release of the NSOAS22 model, there were some known issues, such as boundary connection problems in blockwise solutions and a relatively high noise level. By solving these problems, a new global marine gravity model, NSOAS24, is derived based on sea surface slopes (SSSs) from multi-satellite altimetry missions. Firstly, SSSs and along-track deflections of vertical (DOVs) are obtained by retracking, resampling, screening, differentiating, and filtering procedures on the basis of altimeter waveforms and sea surface height measurements. Secondly, DOVs with a 1′×1′ grid interval are further determined using Green's function method, which applies directional gradients to constrain the surface, least-squares fit to constrain noisy points, and tension constraints to smooth the field. Finally, the marine gravity anomaly is recovered from the gridded DOVs according to the Laplace equation. Throughout the entire processing procedure, improvements in accuracy are expected for the NSOAS24 model due to the following changes, e.g., supplementing recent mission observations and removing old mission data, optimizing the step size during Green's function method, and special handling in nearshore areas. These optimizations effectively resolved the known issues of signal aliasing and the “hollow phenomenon” in coastal zones. Typical altimetry-derived marine gravity models are the DTU series released by the Technical University of Denmark and the S&S series...