New OS Letter: Synoptic observation of a full mesoscale eddy lifetime and its secondary instabilities in the Gulf of Mexico

4 September 2025

Oceanic eddies are giant swirling currents that help transport heat, nutrients, and pollutants across the ocean. However, their life cycle has never been observed in detail. Using new satellite data, the author tracked an intense eddy in the Gulf of Mexico, describing its life cycle from birth during a 6-month period. The observations reveal small-scale turbulence surrounding it and interactions with other structures that shape its evolution, validating decades of numerical studies.

Co-editor-in-chief's statement: The authors present the first synoptic characterisation of an oceanic mesoscale eddy's full life cycle using groundbreaking SWOT satellite altimetry. This unprecedented view challenges the long-standing perception of eddies as simple, elliptical structures, revealing the crucial role of mesoscale interactions in their evolution. The SWOT results capture intense submesoscale turbulence at the eddy's rim, exposing secondary instabilities that likely drive its dissipation. These findings not only validate decades of vortex theory but also open new frontiers in our understanding of oceanic turbulence.

Contact: Charly de Marez (charly@hi.is)