Stretching fields and lines in the transport dynamics of the Western Mediterranean

We summarize recent work on the location of Lagrangian structures
in velocity fields obtained from realistic simulations and from
satellite altimetry of the surface layers of the Mediterranean
sea. Finite-size Lyapunov exponents are found to be useful
quantities to characterize stretching and compressing structures,
and their implications for mixing. Direct calculation of
hyperbolic points and their stable and unstable manifolds
identifies ocean structures, and allows the use of the tools of
lobe dynamics to characterize fluid transport.