Evaluation of MODIS snow cover products over Canadian regions

New snow cover products from the MODIS sensor on NASA EOS Terra satellite Terra have particular interest for both climate and hydrological applications. With the public release of the first MODIS snow cover products in late 2000, the Climate Research Branch of the Meteorological Service of Canada began an evaluation of the MODIS derived snow cover information over selected Canadian regions. This evaluation is being conducted as part of "CRYSYS", which is a Canadian research investigation that is focussed on understanding variability and change in the Canadian cryospheric system using remote sensing, modelling and conventional data. The goal of this evaluation is to assess the temporal and spatial accuracy of the MOD10 snow extent maps. Our evaluation method is designed to examine the difference between the MOD10 snow classification and other types of snow cover data (e.g., SSM/I derived snow water equivalent maps and surface snow depth observations). In addition, it is possible to study any systematic differences related to land cover type and other meaningful parameters. The large volume of MODIS data and a large number of possible testing avenues represented a challenge for the experimental design. This paper presents preliminary results from the evaluation of the MODIS snow cover products for the prairie and boreal forest regions in western Canada and the taiga region in northern Quebec (eastern Canada).