Simulating Seasonal Variability of Circulation and Hydrography on the Scotian Shelf

A three-dimensional shelf circulation model is used to simulate the seasonal variability of circulation and hydrography on the Scotian Shelf over the eastern Canadian seaboard. The model is a modified form of an operational forecast system known as DalCoast3. The model is forced by forecast winds and atmospheric pressure produced by GEM, a Canadian numerical weather prediction model. Climatological temperature and salinity are used to initialize the model, and as lateral open boundary inputs. The monthly mean currents from a baroclinic circulation model of the northwest Atlantic Ocean are used as inputs to represent remotely forced flows. A new data assimilation method developed by Thompson et al. (2006b) is used to constrain model temperature and salinity to their respective climatologies, while allowing short-term (O(days)) variations to evolve prognostically. The model produces southwestward flows along the Nova Scotian coast and along the shelf break, which have been observed in the past. The pattern of simulated volume transport over the Scotian Shelf is qualitatively similar to those from past model studies, and the transport across a section on the inner shelf is also comparable to values calculated from observations.