Applying Lagrangian Coherent Structure Techniques to Map Sea Surface Transport

Part I: Coastal surface transport patterns are determined from Lagrangian Coherent Structures(LCSs) computed from HF radar determined 2-D surface currentvelocities off the coast of Northern California. The LCS maps, which identify confluence and shear in flow, are compared to satellite SST fields under during different wind-forcing regimes. SST fronts are identified by LCSs when winds are light and the LCS fields do not match the SST fields as well when winds are strong. Part II: Persistent barriers in transport in the northeastern Gulf of Mexico (NWGoM) are determined from climatological LCSs computed from climatological surface current velocities from an18-year simulation. A persistent mesoscale attracting barrier that runs along the shelf break is identified that prevents exchange between the shelf and the deep ocean. The LCSs are verified with simulated tracers and satellite-tracked drifters. The results have direct applicability for predicting and mitigating potential oil spills.

Speaker: Dr. Matt Gough, Naval Postgraduate School