Abstract:
This study describes the characteristics of extensive small-scale coastal ocean eddies in the Southern California Bight. These surface features were primarily detected by using ERS-1 and ERS-2 synthetic aperture radar (SAR) satellite imagery from 1992 to 1998. The eddies, predominantly cyclonic in their rotation, appeared to result from several forcing mechanisms. They were primarily observed within the Santa Barbara Channel and the Santa Monica-San Pedro Basin regions and appeared to be seasonal in their distribution. Observed eddy diameters were all less than 50 km, with over 70% less than 10 km. The SAR data were complemented by sea surface temperature measurements derived from advanced very high resolution radiometer satellite imagery, as well as in situ data from moorings and drifters that provided substantial verification of the small-scale eddies. These findings are significant in that the eddies were, in general, smaller in size and more abundant than previously reported. Additionally, these results provide further evidence of the complex near-surface circulation within the Southern California Bight, with important implications for nutrient flux, productivity, plankton patchiness, larval transport and recruitment, and dispersal of pollutants.

Caption:
Imagery (top image) of the Santa Monica Bay/Santa Monica Basin area from ERS-1 SAR acquired December 19, 1994, at 1834 UTC. Areas A and B denote the two largest eddies present; areas C, D, E, and 'F' denote smaller eddies. CAT, Catalina Island; boxed area off Catalina is enlarged in subsequent image (bottom image).

Caption:
Coincident SeaWiFS Chlorophyll-a and AVHRR SST imagery from October, 1997 show a small coastal ocean eddy propagating westward across the Santa Barbara Channel, CA. These eddies have important implications for nutrient flux, primary productivity, plankton patchiness, larval transport and recruitment, and the dispersal of pollutants.

Reference:
DiGiacomo, P. M., and B. Holt, 2001: Satellite observations of small coastal ocean eddies in the Southern California Bight. J. of Geophy. Res.-Oceans, 106, 22521-22544.