Abstract
The temporal evolution of a flow reversal during upwelling conditions along New Jersey's inner shelf is characterized with shipboard, moored, and remote observations. The flow reversal occurs nearshore in the form of a subsurface jet with maximum velocities exceeding 30 cm/s. The jet is most intense in the thermocline, commences during maximum alongshore wind stress, and has a spin‐up time approximately equal to the local inertial period. The jet also has a surface signature apparent in ocean current radar data that shows the jet veering offshore and feeding an upwelling center that drifts southward at 5 cm/s. Moored instrumentation within the upwelling center indicates that cross‐shelf transport in the warm surface layer is consistent with the predicted Ekman transport prior to the spin‐up of the jet, but exceeds Ekman transport thereafter. However, onshore transport in the lower layer never compensates for offshore flow in the surface layer, suggestive that the mass balance requires a three‐dimensional closure. Finally, we suggest that the flow reversal provides a significant fraction of cool water to the evolving upwelling center, and that the offshore veering is due to enhanced friction over a shoaling and rougher topography.