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.