Surface Water and Ocean Topography (SWOT) Observations Unveil Small Mesoscale Variability on the East Greenland Shelf

Abstract In the Arctic, mesoscale ocean processes occur at much smaller scales (5–60 km) than at mid‐latitudes (50–100 km), and conventional altimetry thus only resolves the largest of these signals. Here we show how high‐resolution measurements from the Surface Water and Ocean Topography (SWOT) satellite can be used in conjunction with conventional nadir altimetry to drastically enhance detection of mesoscale processes in the Nordic Seas—a critical exchange region between the North Atlantic and the Arctic, where sea ice presents observational challenges. We developed 2‐km resolution maps of ocean topography, geostrophic currents, and relative vorticity from April 2023 to October 2024 by interpolating SWOT and nadir altimetry data in space and time. These maps enable the exploration of fine‐scale ocean processes (20–100 km) that were previously unresolvable by conventional altimetry. We demonstrate coupled physical–biological processes in a 20‐km anticyclonic eddy using co‐located observations of sea surface temperature and chlorophyll‐a.