Role of submesoscale instabilities in the lateral transport and mixing of freshwater

by Gualtiero Badin

At scales smaller than the synoptic eddy scales, the so called submesoscale, the dispersion of tracers, and freshwater amongst them, is not diffusive. In particular, if the tracer exhibits exponential dispersion in time, the dynamics controlling it can be chaotic.

Plans for  the project are:

We will study the properties of the chaotic dispersion of tracers and freshwater, using Lagrangian techniques derived from the study of chaotic dynamical systems. In particular we will employ three dimensional Finite Time and Finite Separation Lyapunov Exponents (FTLEs and FSLEs respectively, see Figure). FTLEs and FSLEs can provide a mapping of stirring. We will also work theoretically on the identification of Lagrangian Coherent Structures (LCSs), which represent mixing barriers, and that can be important for the lateral and vertical transfer of freshwater.