Modelling Temperature, Currents and Stratification in Placentia Bay

Placentia Bay is an important spawning and nursery ground for Atlantic Cod (Gadus morhua) and a vital shipping corridor for Newfoundland industry, but our ability to forecast the bay circulation is limited. In this study, a three-dimensional (3-D) circulation model based on a finite-volume coastal ocean model (FVCOM) was developed in 1999 to simulate temperature, currents and stratification. The model is forced at the lateral open boundaries with five leading tidal constituents and non-tidal sea surface elevation and at the surface with wind and heat flux. The open boundary temperature, salinity and non-tidal sea levels are derived from a larger-scale shelf model. Simulated tides agree well with tide-gauge data, with a root sum square (RSS) error of 4.6 cm for the elevations of the five tidal constituents and a relative root mean square (RMS) error of 37% for M-2 tidal currents. The modelled temperature has RMS errors of 1 degrees-2 degrees C. The non-tidal currents show reasonable agreement with moored measurements. The model realistically simulates many features of the bay that may affect early life stages of fish, including the evolution of stratification from spring to fall, the cyclonic circulation in the outer bay and late-spring upwelling on the western side of the outer bay.