We study three dimensional oceanic Lagrangian Coherent Structures (LCSs) inthe Benguela region, as obtained from an output of the ROMS model. To do thatwe first compute Finite-Size Lyapunov exponent (FSLE) fields in the regionvolume, characterizing mesoscale stirring and mixing. Average FSLE values showa general decreasing trend with depth, but there is a local maximum at about100 m depth. LCSs are extracted as ridges of the calculated FSLE fields. Theypresent a "curtain-like" geometry in which the strongest attracting andrepelling structures appear as quasivertical surfaces. LCSs around a particularcyclonic eddy, pinched off from the upwelling front are also calculated. TheLCSs are confirmed to provide pathways and barriers to transport in and out ofthe eddy.
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