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

2 pages, 2 figures.-- PAMM Special issue: "Sixth International Congress on Industrial Applied Mathematics (ICIAM07) and GAMM Annual Meeting, Zürich 2007"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 transportParts of this work have been supported by CSIC (grants PI-200650I224 and OCEANTECH), Royal Society-CSIC cooperation agreement (B2003GB03), MEC and FEDER (projects IMAGEN, CONOCE2 and FISICOS), ONR (Grant No. N00014-01-1-0769), and European Commission (projects MERSEA and 024717-DEMETRA)Peer reviewe