Observations Of Sea Ice Drift Off Newfoundland Using Satellite Imagery And Ice Beacons

Daily se� ice velocity fields were obtained by manually tracking ice features in 80 pairs of sequential cloud-free visible NOAA/AVHRR satellite images for the region off Labrador and Eastern Newfoundland from 1984-1986. Although cloud-free images were found for winds from all directions, the images were least likely to be cloud-free when winds were onshore. During the winters of 1985 to 1987, ice velocities were also obtained using a total of 28 Argos satellite-tracked ice beacons, deployed off the Labrador coast by helicopter. The imagery-derived velocity fields were in good agreement with these data. With light to moderate winds, the influence of the Labrador Current could clearly be seen at the shelf break. Strong topographic steering was evident around the numerous banks and saddles on the shelf. Daily geostrophic wind, which was calculated from FNOC surface pressure data on a 380 km grid, accounts for about half the variance in daily ice velocity, for both the imagery and beacon data.