Submesoscale Dynamics in the Wintertime North Western Atlantic

Lateral mixing at scales below 10~km was investigated in a large collaborative effort including theory, observations and numerical simulations. We present realistic numerical solutions of the winter time North Western Atlantic and will compare with recent observations of the submesoscale in the area. An overview is presented for submesoscale circulation and tracer distributions that are generated through downscale processes from mean and mesoscale flows. These structures are typically fronts, filaments, vortices, wakes, ageostrophic instabilities, and emitted inertia-gravity waves. They are especially active in the upper ocean and in broad zones around topographic slopes, which partly overlap with the surface and bottom turbulent boundary layers. Their characteristics are significantly in conflict with those of quasi-geostrophic dynamics. Submesoscale flows provide a forward cascade of energy as a route to dissipation for the general circulation and induce important lateral and diapycnal mixing where they are active.