Dynamics of wind-forced coherent anticyclones in open ocean

1 We numerically study the dynamics of coherent anticyclonic eddies in the ocean interior. For 2 the hydrostatic, rotating, stably-stratified turbulence we use a high-resolution, Primitive3 Equation model forced by small-scale winds in a idealized configuration. Many properties 4 of the horizontal motions are found to be similar to those of two-dimensional and quasi5 geostrophic turbulence. Major differences are a strong cyclone-anticyclone asymmetry, linked 6 to the straining field exerted by vortex Rossby waves, which is also found in shallow water 7 flows, and the complex structure of the vertical velocity field, which we analyze in detail. 8 Locally the motion can become strongly ageostrophic, and vertical velocities associated with 9 vortices can reach magnitudes and levels of spatial complexity akin to those reported for 10 frontal regions. Transport and mixing properties of the flow field are further investigated by 11 analyzing Lagrangian trajectories. Particles released in the pycnocline undergo large vertical 12 excursions due to the vertical velocities associated to the vortices, with potentially important 13 consequences for marine ecosystem dynamics. 14