Improving High-Frequency Marine Gravity Anomaly Recovery: The Efficacy of SWOT Wide-Swath Altimetry

For the traditional 1-D nadir altimetry measurements, the spatial resolution of the sea surface height (SSH) measurements is restricted. However, the new wide-swath altimeters like Surface Water and Ocean Topography (SWOT) are anticipated to enhance spatial resolution and thereby improve the accuracy of derived marine gravity anomalies, particularly in high-frequency signals. The study investigates the efficacy of L2 KaRIn Beta data of SWOT in recovering high-frequency marine gravity signals. CryoSat-2 data was used for comparison. The first-order difference of shipborne gravity data along ship tracks was used as the reference to investigate the high-frequency accuracy of gravity derived from SWOT and CryoSat-2 at different point spacings, respectively. The research results show that compared to CryoSat-2 satellite data, when the point spacing is less than 2 km or greater than 6 km, the accuracy improvement is relatively small, less than 3.0%. However, within the 2-4 km range, the accuracy improvement ranges from 6.8% to 7.9%. When the point spacing is between 4 and 6 km, the accuracy improvement ranges from 5.0% to 6.7%. Therefore, when the point spacing is greater than 2 km and less than 6 km, the accuracy improvement is obvious. The results show that SWOT wide-range altimeter satellite has obviously improved the accuracy of traditional altimeter gravity inversion in high frequency (especially in the range of 2-6 km).