Semi-operational snow melt monitoring using ERS SAR

In 1997 HUT, FEI and FGI (Finnish Geodetic Institute) started a joint project which aims to develop a operational snow monitoring system in Finland. This method applies both traditional methods (in situ measurements and hydrological models) together with satellite borne data. The project is especially concentrated to monitor the snow melt period during spring time. The test area is located in Northern Finland and it consist of the drainage area of River Kemi, which is the largest river in Finland. Several ERS-2 SAR images has been acquired from the test site during spring 1997. These images cover totally the snow melt period starting from dry snow and ending to wet ground. The result has been compared to in situ measurements made on the climatological stations (snow depth precipitation and air temperature) and on the specially designed snow courses which are used for current operative snow mapping. The SAR derived maps are compared with snow melt classification made using NOAA AVHRR data. The SAR derived results show a good agreement both with in situ measurements and AVHRR classification