High-Resolution Observations of Submesoscale Eddies in the Coastal Ocean

Burkard Baschek1, Geoffrey B Smith2, David Miller3, Ingrid M. Angel Benavides1, Ryan P North4 and George O Marmorino5, (1)Helmholtz-Zentrum Geesthacht, Institute of Coastal Research, Geesthacht, Germany, (2)Naval Research Laboratory, Washington, DC, United States, (3)US Naval Research Laboratory, Washington, DC, United States, (4)University of Hamburg, Institute of Oceanography, Hamburg, Germany, (5)Naval Research Lab DC, Washington, DC, United States
Abstract:
High-resolution observations during the Submesoscale Experiments (SubEx) off Southern California reveal the fast dynamics of submesoscale eddies in the coastal ocean. A multi-platform approach with planes, several vessels and floats yields a horizontal and vertical resolution of <1 m. Repeat observations every 5 to 15 min show the fast rotation of vortices characterized by sharp gradients of 1°C/m and high Rossby numbers >10. The rapid mixing of surface water with the colder eddy core indicates the fast evolution and decay of the eddies. The observations suggest a close link between physical processes and phytoplankton concentrations.

Observations were carried out with aerial sea surface temperature and hyperspectral measurements, rapid in situ measurements with a towed instrument array, as well as surface und subsurface velocity measurements with Radar and Acoustic Doppler Current Profilers. Additional SAR, SST and ocean color satellite imagery is used to investigate the occurrence of submesoscale eddies in the coastal ocean.