M. Lisa Beal (Rosenstiel School of Marine, Atmospheric and Earth Sciences, University of Miami, Miami, FL, USA, United States); Guillaume Novelli (Rosenstiel School of Marine, Atmospheric and Earth Sciences, University of Miami, Miami, FL, USA, United Sates); J. Thomas Farrar (Woods Hole Oceanographic Institution, Woods Hole, MA, USA, United States)

Launched in December 2022, the SWOT (Surface Water and Ocean Topography) satellite provides unprecedented sea surface height (SSH) observations at a spatial resolution of 2 km × 2 km. However, SSH measurements from SWOT may include contributions from unbalanced motions, which can pose challenges when estimating surface currents and vorticity. This study aims to investigate submesoscale variability in the Cape Basin by combining SWOT data with traditional altimetry, sea surface temperature (SST), chlorophyll-a, and in situ measurements from Shipboard ADCP and X-band Radar collected during the QUICCHE campaign in March 2023. This integrated approach highlights SWOT’s potential to resolve fine-scale ocean dynamics in the region. To assess the accuracy of surface velocity and vorticity estimates, two SSH-based derivation methods were applied: finite-difference (stencil) derivatives and a fitting kernel method using multiple spatial windows (3 km, 5 km, 7 km, 9 km, 11 km, and 13 km). The fitting kernel method with a 9 km window provided the best results, capturing finer-scale structures with reduced noise. Velocities derived using this method showed good agreement with in situ observations, with root-mean-square errors (RMSE) of 0.20 m/s for ADCP velocities and 0.22 m/s for X-band radar velocities.