Wide-swath satellite altimetry reveals hotspots of small mesoscale eddies in the western Arctic Ocean

Abstract Ocean eddies play crucial roles in climate and marine ecosystems. Still, small mesoscale eddies in the climate-sensitive and biologically unique Arctic Ocean remain poorly characterized and understood due to the coarse resolution of traditional gridded altimetry products and sparse in-situ observations. Here, we show that the Surface Water and Ocean Topography satellite mission overcomes these limitations through unprecedented two-dimensional high-resolution measurements of sea level anomalies. We demonstrate this wide-swath satellite altimetry’s capability to quantify previously unresolved eddy properties, revealing three persistent hotspots of mesoscale eddies in the southern Beaufort Sea that actively transport low-salinity, heat-retaining, and nutrient-enriched waters from the continental shelf to the interior basin. The observed eddies demonstrate their critical role in shelf-basin exchange while revealing biases in current high-resolution models. These findings advance our understanding of Arctic mesoscale processes and provide essential benchmarks for improving ocean models for this rapidly changing environment.