Observations of localized submesoscale kinetic energy fluxes

Ocean dynamics at the submesoscale play a key role in mediating upper-ocean energy dissipation and dispersion of tracers. Observations of ocean currents from synoptic mesoscale surveys at submesoscale resolution (250~m--100~km) from a novel airborne instrument (MASS DoppVis) reveal that the kinetic energy spectrum in the California Current System is nearly continuous from 100~km to sub-kilometer scales, with a $k^{-2}$ spectral slope. Although there is not a transition in the kinetic energy spectral slope, there is a transition in the dynamics to non-linear ageostrophic interactions at scales of $mathcal{O}$(1~km). Kinetic energy transfer across spatial scales is enabled by interactions between the rotational and divergent components of the flow field at the submesoscale. Kinetic energy flux is patchy and localized at submesoscale fronts. Kinetic energy is transferred both downscale and upscale from 1~km in the observations of a cold filament.