An automatic system for operational snow-cover monitoring in the Norwegian mountain regions

Describes an operational snow-cover monitoring system using satellite imagery. The system has for several years been developed for the largest Norwegian hydroelectric company, the Norwegian Energy Corporation (Statkraft). The snow-cover data is an important information source for the hydrological simulation models run in the melting season from April to August. Accurate predictions of water amounts from the snow-covered areas are crucial for power station production planning and planning of long-term contracts. The system can be operated in semi-automatic and automatic modes and is based on NOAA AVHRR imagery. Geocoded imagery is calibrated against pre-selected stable calibration areas before the classification. The classification algorithm is based on an empirical reflectance-to-snow-cover model. The classified result is then combined with various GIS data sources depending on the desired result. Ongoing work for further development is also presented: Image data aggregation from a time series of partially clouded imagery, terrain normalization, automatic geocoding, and utilization of microwave data