Moving Geoid Gradient Method for High-Precision and High-Resolution Gravity Recovery From SWOT Wide-Swath Data

Le résumé fourni par la source

High-resolution sea surface heights (SSHs) can be obtained from the wide-swath data of the Surface Water and Ocean Topography (SWOT) project. The distance between two points used to calculate geoid gradients from SSH data significantly influences the accuracy of these gradients. The moving method is proposed to obtain high-precision and high-resolution geoid gradients for gravity recovery, wherein gradients are calculated using SSH data from two points that are separated by a defined distance rather than relying on adjacent points. Marine gravity models around the South China Sea are derived from SWOT-measured SSHs and CryoSat-2-measured SSHs, respectively. The global marine gravity models with high international recognition are also used for comparison. Assessed by shipborne gravity data, the accuracy of SWOT-derived gravity from three-direction geoid gradients is significantly higher than that from one-direction geoid gradients along-track, but slightly higher than that from two-direction geoid gradients. The moving method enhances the precision of the SWOT-derived gravity model by approximately 4% and improves its resolution by about 10%. Compared to CryoSat-2-derived and recognized gravity models, SWOT-derived gravity models using the moving method demonstrate accuracy improvements exceeding 12% and resolution enhancements of over 20%. All these verifications show that SWOT data has advantages over traditional altimeter data in the accuracy and resolution of SSH-derived gravity. For gravity recovery from wide-swath data, it is essential to utilize both along-track and cross-track gradients together, while the inclusion of diagonal-track gradients is optional. The proposed moving method significantly enhances the accuracy and resolution of SWOT-derived gravity, showcasing its effectiveness in marine gravity recovery.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.