Drifter observations of coastal surface currents during CODE: The method and descriptive view

TLDR

During CODE, 164 current‑following drifters were deployed off Northern California to observe near‑surface coastal currents. The drifter data reveal energetic mesoscale features—eddies, jets, convergences, and across‑shelf squirts—that dominate across‑shelf transport, with convergences linked to wind reversal and squirts producing cold‑water plumes near coastal promontories.

Abstract

Observations of near‐surface coastal currents were made off the Northern California coast during the Coastal Dynamics Experiment (CODE) by using 164 current‐following drifters. Viewed as flow visualization descriptions, the results disclose a number of energetic mesoscale features that dominate across‐shelf transport. Examples of eddies, jets, convergences and across‐shelf “squirts” are shown and related to moored current observations, wind forcing, and mesoscale features observed in satellite surface temperature imagery. Convergences appear to be most common when currents reverse following relaxation of normally upwelling‐favorable winds. Squirts are apparently the cause of cold water plumes extending away from the coast; they appear most frequently at coastal promontories.