Reconnaissance Snow Survey across Northwest Territories and Nunavut, Canada, April 2007

摘要

During April 2007, a coordinated series of snow measurements were made across the Northwest Territories and Nunavut, Canada, during a 4200-km snowmobile traverse from Fairbanks, Alaska, to Baker Lake, Nunavut. While detailed, local snow measurements have been made as part of ongoing studies at tundra field sites in this region (Daring Lake and Trail Valley Creek in the Northwest Territories), systematic measurements at the regional scale have not been previously collected across this region. Consistent with observations of tundra snow in Alaska and northern Manitoba, the snow cover consisted of depth hoar and wind slab with small and ephemeral fractions of new, recent, and icy snow. The snow was shallow (less than 40 cm deep), usually with less than six layers. Where deposited on lake and river ice, the snow was shallower, denser, and more metamorphosed than where deposited on tundra. The snow characteristics were highly variable at a local scale, but no longitudinal gradients in snow distribution, magnitude, or structure were detected. Lakes and lake ice confounded passive microwave remote sensing of the snow cover in this area because the lake signal overwhelmed the snow signal. Consequently, challenges remain in developing methods to monitor this snow cover by satellite. Appendixes present near-infrared images, snow depths, soot measurements, mercury measurements, ion measurements, and isotope measurements.