Along-Track Marine Geoid Resolution Enhancement With SWOT

Abstract

Satellite altimetry has been the major data source for marine geoid determination·and gravity recovery in recent decades. In general, altimetry-derived geoid and gravity anomaly models are typically released with a 1' × 1' gridding interval. However, their actual spatial resolution is far lower than the nominal ∼2 km level. Therefore, analyzing the marine geoid resolution capability from satellite altimetry observations is crucial for marine gravity recovery studies. The Surface Water and Ocean Topography (SWOT) Mission is a newly launched satellite using advanced radar technology to make headway in observing the·variability of water surface elevations, providing new information through along-track and across-track two-dimensional swath observations. Here, we present the analysis results of marine geoid resolution capability for both typical conventional nadir altimeters and the SWOT Ka-band radar interferometer (KaRIn) in 2° × 2° bins worldwide between 60°N and 60°S. We demonstrate the potential of SWOT KaRIn to capture along-track short-wavelength signals below 10 km and analyze the bin-based statistics of key marine geophysical factors correlated with this marine geoid resolution capability. Generally, SWOT KaRIn exhibits better marine geoid resolution capability over bins with large-scale seamounts or trenches.