Estimates of ice-edge melt rates off Labrador and eastern Newfoundland, Canada

Abstract

For the winters of 1985 to 1989, ice-edge melt rates off Labrador and eastern Newfoundland were calculated from ice charts and satellite-tracked ice beacon data. The ice charts provided ice-edge motion and ice thicknesses, while the beacons provided ice-drift rates and rates of ice-edge retreat. Over the continental slope, ice-edge melt rates, ice-drift rates and heat fluxes required to melt the ice were all higher than those over the continental shelf. Ice-edge melt rates had a mean value of 18.0 km d−1 over the slope but reduced to 4.8 km d−1 over the shelf. Similarly, the mean ice-drift rate was higher over the slope (41.5 km d−1) than over the shelf (12.7km d−1). Ice-edge melt rates increased linearly, as ice-drift rates perpendicular to the edge increased. Estimates of heat fluxes (±30%), required to melt the ice at the ice edge, reached values of 700 W m−2 for 3-day periods and had a mean of 340 W m−2 over the slope and 130 W m−2 over the shelf.