This page shows monitoring statistics for the NOAA/NESDIS (National Environmental Satellite, Data, and Information Service) Interactive Multi-sensor Snow and Ice Mapping System (IMS) snow cover data.
The IMS snow cover product combines ground observations and satellite data from microwave and visible sensors (using geostationary and polar orbiting satellites) to provide snow cover information in all weather conditions. The IMS product is available daily for the northern hemisphere.
It provides a binary information on snow cover (snow or no snow). The model first guess snow cover is compared to that of IMS using a contingency table. Monitoring statistics are expressed using the four elements of the contingency table: Miss rate, Hit rate, false alarm rate and correct-nulls.