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Center for Nonlinear Studies |
The variability of circulation and hydrography over the Eastern Canadian shelf is among the largest in the world’s oceans and is affected by numerous factors such as tides, heat and fresh water fluxes, river discharge and the interaction of western boundary currents. A nested-grid ocean-ice circulation model is developed to examine the main physical processes affecting the circulation and associated subtidal variability in the region. The model has a fine-resolution child model embedded inside a coarse-resolution parent model of the Northwest Atlantic. The combination of the spectral nudging and semi-prognostic methods is used to reduce the model seasonal bias and drift. The model reproduces general features of the observed circulation and subtidal variability during 1988-2004. Numerical experiments and statical analyses are conducted to examine circulation and hydrography on different frequency bands. The model demonstrates that some features of the time-mean circulation are affected by the temporal variability in the atmospheric forcing. Advection of anomalies affects the seasonal variability over the Gulf of St. Lawrence and the Scotian Shelf, as well as the interannual variability over the Labrador Shelf. By contrast, over the Newfoundland and Scotian shelves, the interannual variability is mainly affected by anomalies generated internally by the model non-linear dynamics in the deep waters to the south of the Grand Banks. These results point out key physical processes to consider in studies to improve predictability on the region.
Host: Elizabeth Hunke