<p>Sub-mesoscale (SMS, <10 km scale) ocean circulation is characterized by high vorticity and deviation from geostrophic balance. It can result in large effects on biology and chemistry due to the large vertical velocities (x10-100 than mesoscale) and resulting down/up welling circulations, as well as significant effects on material retaining and dispersion. </p><p>Modelling and observing the Submesoscale is challenging due to stringent demands on spatio-termpoal resolution, and due to its strong interactions with both larger (mesoscale) and smaller (turbulence and waves) circulations. I will report on the first Sub-mesoscale-resolving numerical modelling study in the East Mediterranean Sea, and (likely universal) findings on the patterns of cross-scale energy exchange between the Sub-Mesoscale and mesoscale circulation, which controls the seasonal evolution of both circulations. Secondly I will show in the model boundary current variability can spawn Sub-Mesoscales year-round (while open ocean formation is largely limited to winter). This will be backed by our (and the first) systematic observations of a Sub-mesoscale vortex formed in summertime via boundary current meandering.</p><p> </p><p> </p>
