Francisco J. Beron-Vera (University of Miami):
Stability of the Malvinas Current

Deterministic and probabilistic tools from nonlinear dynamics are used to assess enduring near-surface Lagrangian aspects of the Malvinas Current. The deterministic tools are applied on a multi-year record of velocities derived from satellite altimetry data, revealing a resilient cross-stream transport barrier. This is composed of shearless-parabolic Lagrangian coherent structures (LCS), which, extracted over sliding time windows along the multi-year altimetry-derived velocity record, lie in near coincidental position. The probabilistic tools are applied on a large collection of historical satellite-tracked drifter trajectories, revealing weakly communicating flow regions on either side of the altimetry-derived barrier. Shearless-parabolic LCS are detected for the first time from altimetry data, and their significance is supported on satellite-derived ocean color data, which reveal shapes that quite closely resemble the peculiar V shapes, dubbed “chevrons,' that have recently confirmed the presence of similar LCS in the atmosphere of Jupiter. Finally, using in-situ velocity and hydrographic data, conditions for nonlinear symmetric stability are found be satisfied, suggesting a duality between Lagrangian and Eulerian stability for the Malvinas Current.

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