Subtidal Response of Scotian Shelf Circulation to Local and Remote Forcing. Part I: Observations

Data collected during the Canadian Atlantic Storms Program (CASP) suggest that two primary current regimes exist on the Scotian Shelf during winter. Moorings inside the 100-m isobath feature currents that are parallel to the general bathymetry and have small eastward mean velocities. The time-varying part of the flow is nearly rectilinear alongshelf at typical maximum velocities of 0.2–0.3 m s−1 and oscillates on 2–5-day periods in response to meteorological forcing. The current at locations beyond the 100-m isobath exhibits a persistent westward flow of about 0.3 m s−1, denoting the dominance of the Nova Scotian Current, although smaller magnitude along- and cross-shelf fluctuations occur at synoptic frequencies. Flow in both regions is largely uniform with depth at this time of year. The velocity response to local and remote sources of forcing was examined using a frequency (ω)-dependent multiple regression model. Flow is dominated by nonlocal forcing at ω < 0.2 cpd; alongshelf wind stress is t...