Observations of subtidal currents over the northern California continental slope and adjacent basin: Some evidence for local wind forcing

Abstract

Currents at several depths were monitored on the upper slope, on the midslope and over an adjacent deep‐sea basin off northern California for nearly simultaneous periods from 4 to 14 months. In 1980 and 1981, subtidal current fluctuations with periods shorter than 32 days were oriented parallel to the topography over the slope but had no consistent orientation over the basin. Mean currents flowed northwestward over the slope and southward in the basin. The subtidal current fluctuations in the three regions were generally incoherent with each other and were weakly coherent with wind stress and coastal sea level. Observations of wind‐driven flow over the slope are consistent with a nonresonant model for wind‐forced shelf and slope currents, but the observations are too limited to define specific model parameters. Over the basin, the wind‐forced currents have characteristics similar to those predicted by stochastic models for wind‐forced flow in the open ocean.