The use of ERS-1 SAR data in snow melt monitoring

ERS-1 SAR data, airborne data and in situ snow data were acquired for the Sodankylä test site in northern Finland for the winters of 1991–1992 and 1992–1993. The test area consists of sparsely forested areas (pine, mixed forests, and mires) and open areas (bogs, lakes, clear-cut areas, and urban area). A set of multitemporal ERS-1 SAR images covering the two winters have been analyzed and the results have been compared with in situ surveys and a digital land-use map. The results indicate that even in the presence of forest canopies 1) wet snow can be distinguished from other soil/snow conditions (dry snow and bare ground), and 2) snow melt maps can be derived from SAR images. Snow-melt maps indicate areas fully covered with wet snow, partly melted areas and snow-free areas.