RESPONSE OF SEA ICE DRIFT TO WIND FORCING ON THE NORTHEASTERN NEWFOUNDLAND SHELF

Observations of sea ice drift obtained with satellite-tracked ice beacons in March-April of 1988 and 1989 have been used to examine the response of sea ice drift to wind forcing over the northern Newfoundland continental shelf. The short-term (5-20 days) response of sea ice drift ranges from 2.6 to 5.4% of the local wind over much of the inner continental shelf, which is comparable to that in the Bering Sea and the Antarctic but larger than that in Arctic. Sea ice drifts to the right of the local wind, at angles ranging from 10-degrees to 63-degrees. The response to wind forcing is largest near the ice edge, both over the middle portions of the shelf and along the southern margins of the seasonal ice zone and during strong and steady wind of several days' duration. The large wind-driven response of ice drift observed in this study, in comparison with the Arctic, may result from (1) reduced levels of internal ice stress associated with the generally thin ice cover and lower areal concentration of sea ice, (2) large atmospheric drag coefficients associated with the small ice floes in areas of comparatively higher ice concentration, and (3) smooth ice bottom caused by melting. In nearshore areas the ice to wind coupling is reduced owing to larger internal ice stresses experienced locally due to ice pileup.