Laura HERRAIZ BORREGUERO (CSIRO, Australia); Ole RIEKE (University of Tasmania, Australia); Yuhang LIU (University of Tasmania, Australia); Annie FOPPERT (University of Tasmania, Australia); Matthis AUGER (University of Tasmania, Australia); Yann-Treden TRANCHANT (University of Tasmania, Australia); Bea PENA-MOLINO (CSIRO, Australia); Maxim NIKURASHIN (University of Tasmania, Australia)

Fine scale observations in the Antarctic Shelf in front of the fast-thinning Denman Glacier with SWOT and in situ observations reveal strong coastal current and sub-mesoscale eddies capable of deep water-masses modification.
The Denman is one of the fastest thinning glaciers in Antarctica. This has been informed by remote sensing observations, and it has been pointed to ocean driving a great deal of the mass loss by models. The glacier area had however never been visited by oceanographic vessels until very recently. The Denman Marine Voyage on-board RSV Nuyina visited the region in March-April 2025 and deployed a significant oceanographic investigation with some datasets already showing stunning small scale ocean processes. SWOT observations suggest very strong currents in the vicinity of the glacier and induced very small and strong instabilities and eddies. This was difficult to assess given the presence of the ice tongue, icebergs and seaice, all prone to contaminate and corrupt sea level anomalies. We developed ways to compute the balanced motion currents from swot at smaller scales (O10km). The ship ADCP data and iceberg drifts confirmed the strength of the currents and small, short-lived eddies. Those sub-mesoscale dynamics are effectively reproduced by a local high-resolution model. This presentation will show the results of this analysis and the inferred deep penetration of surface waters in presence of these sub-mesoscale eddies, the interaction with icebergs and water masses modification. This study highlights the step change of the critical coastal Antarctic observability brought by SWOT.