Sea ice thickness distribution in the Arctic Ocean

Data from the unclassified literature were reviewed to determine the regional and seasonal distributions of sea ice thickness, pressure ridging statistics, frequency of occurrence of polynyas, and keel/sail height ratios. Seasonal and regional maps and histograms of these properties were constructed. The majority of the data were obtained from submarines equipped with a narrow-beam, upward-looking sonar. As determined from an analysis of 17 submarine cruises, the overall mean thickness of Arctic sea ice above 65° N, including both deformed and undeformed ice, is 2.9 m with a standard deviation of 1.8 m. The overall seasonal mean ranges from approximately 2.4 m in spring to 3.3 m in summer. Local mean ice drafts ranged from less than 1 m near the marginal ice zone to greater than 7 m to the north of the Canadian Archipelago. Histograms of sea ice draft reflect a bimodal distribution in winter and spring, an effect of the presence of thin first year ice. Due to ice melt in summer and autumn only a single mode of much thicker multiyear ice is observed.