Abstract:
We discuss connections between inner-shelf and mid-shelf circulation near Point
Conception, California, as well as the wind forcing of inner-shelf circulation. Point
Conception marks the southern edge of a major upwelling zone that extends from Oregon
to central California. The coastline makes a sharp eastward turn at Point Conception, and
the Santa Barbara Channel to the east is generally assumed to be an upwelling shadow.
Consistent with this regional division, inner-shelf currents are strongly correlated with
wind north of Point Conception, but not in the Santa Barbara Channel. One exception to
this generalization is a location in the Santa Barbara Channel, near a pass that cuts through
the coastal mountains, where local winds have a dominant cross-shore component and
directly drive cross-shore currents over the inner shelf. Inner-shelf currents in the Santa
Barbara Channel, when compared with mid-shelf currents in that area, are weaker, but
strongly correlated. By contrast, inner-shelf currents north of Point Conception show a far
greater incidence of poleward flow than is seen over the mid-shelf in that area. Poleward
flow events, lasting 1–5 days, transport warm water from the Santa Barbara Channel
around Point Conception to the central California coast. These events are associated with
relaxation of the generally equatorward wind, but not always with mid-shelf flow reversals.
