| Popis: |
Lack of thermal insulation of the ground by snow cover is the prime factor causing permafrost to occur in the alpine tundra areas near Schefferville (55°N, 67°W). Lack of protection by seasonal snow cover is also the prime factor suppressing the growth of brush vegetation that is omnipresent elsewhere. The sensitivity of C-band synthetic aperture radar (SAR) to slight variations in an already sparse vegetation cover permits areas of shallow snow cover, and thus strong wintertime heat loss, to be identified. The map of such heat loss zones produced from a high-resolution HH-polarized C-band SAR-image imaged by the Canada Centre for Remote Sensing in early June 1991, compares favorably with previous permafrost maps produced by the Iron Ore Company of Canada. |
