The Canadian initiative “Variability and Change in the Canadian Cryosphere” is a contribution to the International Polar Year project “State and Fate of the Polar Cryosphere”.  This initiative incorporates an observational component (ground-based and remote sensing) and a modelling component.  One sub-theme of the modelling component involves offline testing of the cryospheric aspects of the Canadian Land Surface Scheme, CLASS.

The testing is being carried out over a domain centred on the province of Quebec in eastern Canada, at a resolution of 1/4°,  The modelling time period incorporates one spin-up year (1991-1992), followed by six simulation years (1992-1998).  This includes the warm El Nino winter of 1997-98 (the lowest snow year on record in Quebec).

Atmospheric forcing data have been obtained from ERA-40 reanalyses, scaled down in space and time using the Environment Canada GEM model as the interpolator.  The background soil and vegetation data used were compiled over North America at 1 km resolution for the Mackenzie GEWEX study.  Validation data consist of several multi-year snow depth and mass datasets, NOAA snow cover data, and CANSIS datasets, containing gridded screen temperature and precipitation observations.

Studies are being carried out to determine the sensitivity of the simulated surface energy and moisture fluxes to the surface vegetation and soil aggregation strategy, and to the presence of lakes.  (Lake surface temperatures are being obtained from NOAA Pathfinder data.)  These will provide valuable information on the discretization of basins for hydrological modelling.