Wind-Forced Cross-Shelf Circulation on the Northern California Shelf*

Abstract

Velocity time series are used to study cross-shelf circulation on the northern California shelf and to examine classical ideas of locally wind-forced cross-shelf circulation. A simple linear two-dimensional model of crossshelf transport is compared to estimates of cross-shelf transport in the near surface, interior, and near bottom. In winter, when wind forcing is brief and episodic, model transports are highly correlated to the total surface flow and show some skill in predicting subsurface cross-shelf flow. The same model does not work well below the surface in summer when persistent upwelling is observed. This suggests a two-dimensional wind-forced model of cross-shelf circulation may have more applicability to the brief wind events observed in winter than to the persistent wind events observed in summer. The reason for this is unclear. Numerous factors not included in the simple linear wind-forced model such as mesoscale features, upwelling fronts, the interaction of flow with topography, baroclinic pressure gradients, remote forcing, and small-scale wind stress all affect cross-shelf circulation. It is possible some of these are more pronounced on the northern California shelf in summer. * Woods Hole Oceanographic Contribution Number 8963.

Influence of larval behavior on transport and population connectivity in a realistic simulation of the California Current System

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The Mean Along-Isobath Heat and Salt Balances over the Middle Atlantic Bight Continental Shelf

“…8) are estimated using the historical hydrographic profiles and a model of the mean cross-isobath current structure . Following , the mean crossisobath volume transport is represented by surface and bottom Ekman transports (U s 5 t sy /r o f and U b 5 2t by /r o f ) and a geostrophic interior transport U i 5 2ghh y /f, and the net cross-isobath transport is assumed to be zero (Dever 1997;:…”

WEST: A northern California study of the role of wind-driven transport in the productivity of coastal plankton communities

“…Since CODE, several other major observational experiments have been conducted over the shelf in the vicinity of Bodega Bay: Northern California Coastal Circulation Study (NCCCS) 1987-89 (Largier et al, 1993); Shelf Mixed Layer Experiment (SMILE) 1988-89 (Dever andLentz, 1994); and Sediment Transport Events over the Shelf and Slope (STRESS) 1988-89 and 1990-91 (Trowbridge and Lentz, 1998. These studies have given insight into the importance of coastal trapped waves and local wind forcing of along-shelf flow (Chapman, 1987;Davis and Bogden, 1989), the identification of surface Ekman layer transport at the mid-shelf (Lentz 1992;Dever, 1997), the asymmetry between upwelling and downwelling conditions in the bottom boundary layer (Trowbridge and Lentz 1991), and the importance of offshore forcing of shelf flows (Largier et al 1993).…”