Drifting and blowing snow field studies in the Canadian North

For a significant part of the year snow covers the ground, or ice, in the Canadian North and offshore areas of the Arctic Ocean. Strong winds are also common and the combination leads to drifting and blowing snow conditions. These in turn can redistribute and sublimate snow cover as well as cause significant and hazardous reductions in visibility.

Modelling studies using the Prairie Blowing Snow Model and the Piektuk model have addressed sublimation issues but both are critically dependent on assumptions about ice particle concentrations and size distributions in the air just above the surface. In order to obtain data on these and related issues we have developed particle counters and imaging systems to address these issues and mounted field measurement campaigns in the Canadian Arctic and sub-Arctic.

From January through April 2004 we deployed particle counters and other meteorological instrumentation on the ice of Franklin Bay in the Beaufort Sea to obtain data on particle number densities at several heights above snow covered first-year ice, visibility and wind and snow conditions. Snow bags were also used. Similar studies were conducted on land at Churchill, Manitoba in winters 2005/6 and 2006/7, including measurements of size distributions, and measurements are currently under way near the airport at Iqaluit, Nunavut as part of the IPY-related Storm Studies in the Arctic program.

Results indicate threshold velocities, show variations of particle number density and size distribution with wind speed and with height above ground, and show relationships with visibility and particle concentration and size. Instrument development issues will also be addressed.