Evaluation of multiple datasets for snow cover indicators for Canada

Snow cover extent (SCE) is an essential climate variable. Indicators of trends in the temporal and spatial patterns of SCE are increasingly used to both monitoring climate variability and change and quantifying regional environmental conditions. However, the choice and accuracy of the indicators are often depends on the input snow cover data. A survey of snow cover indicators is performed to identify those that would satisfy user requirements over Canada in addition to the current practices for international reporting. Four different input data sets are then used to generate snow cover indicators over a five year period (2006-2010): the Canadian Meteorological Centre snow depth analysis with systematic in-situ measurements; cloud free MODIS MOD10C1 SCE product; NOAA Interactive Mapping Service 4km SCE product; and CCRS SCE product that assimilated both CMC inputs and NOAA AVHRR satellite imagery. Then snow cover indicators, including snow cover onset and melt, are evaluated through their sensitivity to documented data uncertainties, by comparison to continuous monitored in-situ data, and through inter-comparison. Recommendations for suitable indicators as a function of input dataset are provided.