RESUME / ABSTRACT  


Modeling the Ice-Ocean Seasonal Cycle in Hudson Bay Foxe Basin and Hudson Strait, Canada

by


François Saucier







The circulation and the seasonal cycle of water mass transformation and sea ice production in the Hudson Bay marine system are examined using a three-dimensional coastal ice-ocean model, with 10 km horizontal resolution and realistic tidal, atmospheric, hydrologic and oceanic forcing. The model includes a level 2.5 turbulent kinetic energy equation, multi-category elastic-viscous-plastic sea ice rheology, and two layer sea ice with a single snow layer. Results from a two year long model simulation between August 1996 and July 1998 are analyzed and compared with observations. The results demonstrate a consistent seasonal cycle in atmosphere-ocean exchanges and the formation and circulation of water masses and sea ice. The maximum sea ice growth rate occurs in a relatively large and persistent polynya in northwestern Hudson Bay, and in western Foxe Basin. Sea ice advection and ridging are more important than local thermodynamic growth in the regions of maximum sea ice cover and thickness that are found in eastern Foxe Basin and southern Hudson Bay. The estimate of freshwater transport to the Labrador Sea confirms a broad maximum during wintertime that is associated with the previous summer's freshwater moving through Hudson Strait from southern Hudson Bay. Tidally-driven mixing is shown to have a strong effect on the modeled ice-ocean circulation.