The correlation between surface drifters and coherent structures based on high-frequency radar data in Monterey Bay

Shadden, S. C., F. Lekien, J. D. Paduan, F. P. Chavez and J. E. Marsden

Deep-Sea Research II, 56, (2009), 161-172

Abstract:

This paper investigates the transport structure of surface currents around the Monterey Bay, CA region. The currents measured by radar stations around Monterey Bay indicate the presence of strong, spatial and temporal, nonlinear patterns. To understand the motion of a passive tracer in the bay, Lagrangian Coherent Structures (LCS) are computed. These structures are mobile separatrices and divide the flow into regions of qualitatively different dynamics. They provide direct information about the fate of particles and are geometrically simpler than particle trajectories themselves. The LCS patterns also reveal the mesoscale flow conditions observed during the AOSN II experiment.

Drifter paths from the 2003 Autonomous Ocean Sampling Network (AOSN II) experiment are compared to the Lagrangian patterns induced by the LCS based on high-frequency radar data. We verify that the fate of the drifters can be better characterized based on the LCS than direct interpretation of the current data. This property can be exploited to optimize drifter deployment.