The Barreirinhas Eddies: Stable Energetic Anticyclones in the Near-Equatorial South Atlantic

We explore the Barreirinhas Eddies, submesoscale vortices generated by North Brazil Current (NBC) off Bight (Brazil, centered at 1.75°S), using vessel-mounted and moored ADCP data, a Global HYCOM reanalysis. These double-stacked anticyclones with incredibly high Rossby Number O (10)] occur independently different depths (high Burger number). Anticyclones number greater than unity are unstable according to inviscid linear theory, hence these features not easily observable mid latitudes. At low latitudes, they last about week, allowing characterization oceanographic surveys. Our analyses suggest this increased stability is due joint effect of strong winds, stratification, proximity equator, topography. Heretofore hypothesized via analytical studies seen in numerical models, our study confirms stabilization process observations, also starting point for description dynamics NBC domain.