Preferential Summer Melt of Deeper Ridge Keels in the Central Arctic
Ocean from Multibeam Sonar Data
Abstract
Sea-ice ridges constitute a large fraction of the total Arctic sea-ice
volume (up to 40%); nevertheless, they are the least studied part of
the Arctic ice pack. Here we investigate sea-ice melt rates using rare
underwater multibeam data that cover a period of one month during the
advanced melt stage in the Arctic summer. We show that the degree of
bottom melt increases with ice draft for first-year and second-year
level ice, and a first-year ice ridge keel, with an average of 0.45 m,
0.55 m, and 0.95 m of total snow and ice melt in the observation period,
respectively. While bottom melt rates of ridge keels are 3-4 times
higher than first-year level ice, surface melt rates are almost
identical. Our estimate attributes 57% of the ridge keel melt
variability to keel draft (36%), slope (32%), and width (27%).