A new window into the oceans: dynamic analysis of sea level anomalies from the SWOT mission

Mesoscale eddies play a fundamental role in ocean dynamics, influencing the transport of energy, heat and nutrients, as well as large-scale circulation. However, their observation remains challenging due to the limited spatial and temporal resolution of conventional altimetry. The Surface Water and Ocean Topography (SWOT) mission, using wide-swath interferometric altimetry, provides unprecedented high-resolution data for studying these structures. This study assesses SWOT's added value in the Algerian Basin, a region characterized by significant eddy activity. A comparative analysis confirmed SWOT's ability to resolve finer-scale variability and retain greater energy at smaller scales compared to conventional altimetry. Focusing on a coastal anticyclonic eddy, SWOT observations were compared with conventional altimetry data and numerical model results. SWOT captured the eddy's structure and evolution with higher precision, revealing previously undetected details, including its dissipation and the subsequent formation of a new structure. The combined analysis of SWOT data and numerical model results highlighted the role of bathymetric interactions in eddy dissipation through potential vorticity loss and increased component of the ageostrophic motion. These findings demonstrate SWOT’s potential to enhance our understanding of eddy dynamics and their interaction with the ocean floor, paving the way for improved high-resolution oceanographic observations.