Coastal Upwelling Off Southwest Nova Scotia Simulated With a High‐Resolution Baroclinic Ocean Model

Abstract

AbstractA high‐resolution baroclinic coastal ocean model is applied to study seasonal circulation and upwelling off South West Nova Scotia (SWNS) based on 1 year simulations for 2010. The model reasonably reproduces tidal currents, seasonal hydrography, and circulation from multiyear observations, in consistence with the observed strong seasonal variations of these properties in the study area. The main physical processes affecting circulation are analyzed using numerical experiments, with focus on the effect of tidal and density induced currents on topographic upwelling. It is confirmed that the shoreward near‐bottom currents and associated upwelling are tidally induced and persistent throughout the year. It is revealed that these currents have seasonal variability, with cross‐isobath component being strong in summer throughout a large area, but weaker and confined to deeper regions in winter. The seasonal variability of Scotian Current is the dominant forcing affecting the variability of onshore bottom currents. Lagrangian particle tracking identifies two major pathways of source waters arriving at the SWNS upwelling region. A large proportion of particles come from the east with the Scotian Current, mostly from the surface layer; and a small portion of water parcels come from a mean depth exceeding 100 m from the Gulf of Maine and Northeast Channel.