Alejandro Bohé (CNES, France); Gwendal Marechal (LEGOS, France); Han Wang (University of Hamburg, Germany); Ryan Dù (Colorado School of Mines, United States); Momme Hell (WHOI, United States); Luc Lenain (Scripps Institution of Oceanography, United States)

SWOT’s Ka-band Radar Interferometer (KaRIn) enables high-resolution mapping of sea surface height (SSH) and significant wave height (SWH), revealing new details of ocean surface variability at meso- and submesoscales. We present early results showing that the KaRIn-derived 2D SWH fields capture sharp sea state gradients associated with eddies, jets, and submesoscale turbulence, as well as fine-scale features linked to wave group modulation. Comparisons with airborne lidar observations from the MASS instrument during the SWOT cal/val campaign demonstrate strong agreement with KaRIn's observations. To help interpretation of these gradients, we introduce the U2H map, an analytical tool that relates SWH anomalies from swells to underlying surface currents through a linear convolution operator. This approach reproduces key features observed in both SWOT and model outputs. We show examples of its application to SWOT scenes and discuss ongoing work to separate the effects of wave groups and currents.