Surface Semi-Geostrophic Dynamics: mixing from local to nonlocal dynamics

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Observational and numerical works show that the ocean displays a significant presence of dynamics at scales smaller than the mesoscale. Understanding the properties of these dynamics and their role in the turbulent transfer and mixing of properties such as heat, nutrients and pollutants is important for the correct parameterization of mixing in climate models. In this project we aim to study the lateral mixing in the ocean by submesoscale dynamics, in particular by ageostrophic eddies produced at boundaries, using the semi-geostrophic approximation. Numerical experiments of surface semi-geostrophic turbulence will be performed in order to study the stirring and mixing of passive tracers. Different experiments at different Rossby numbers will be performed to study the effects of the frontal dynamics on the dispersion of the tracer. Results will be compared with other classic turbulence models, such as the surface quasi-geostrophic approximation.