Dynamics of a Submesoscale Surface Ocean Density Front

Small-scale ocean flows have increasingly ageostrophic dynamics that are important for the ocean energy budget and biogeochemical cycles. Numerical models indicate that the ageostrophic flow and vertical velocities associated with frontogenesis are a dominant mechanism of surface to interior ocean material transport. The increasingly unbalanced flow may also provide a pathway to downscale energy from the mesoscale to microscale.In situ observations of these flows are challenging due to the characteristics of the flow, such as small spatial scales and short lifetimes of hours to days. To observe the physical properties, generation, and evolution of these features, a new experimental method was developed at UCLA that incorporates simultaneous sampling by remote sensing and in situ instruments onboard satellites, aircraft, and vessels.On April 14, 2011, a small-scale frontal feature confined to the upper 10 m of the water column was measured near Catalina Island, California. The front had a maximum horizontal temperature gradient of 0.0031℃ m-1 and slope of 0.0146. To our knowledge, this is the first time such high resolution and comprehensive in situ observations have been made of submesoscale features