Ice thickness distribution in Davis Strait in February from submarine sonar profiles

A submarine sonar profile obtained in Davis Strait by USS Queenfish in February 1967 has yielded the first quantitative data on ice thickness distribution in the region. Within 50–100 km of the ice edge there is a “marginal ice zone” (MIZ) where the mean draft is 0.25–0.51 m, most of the ice (93–100%) is undeformed, and there are many leads but few ridges, all of them less than 6.1 m in draft. The remainder of the region is an “interior zone” composed mainly of first‐year ice with a mean draft of 0.77–1.66 m, increasing slightly from NE to SW. Level ice is less common than in the MIZ (67–91% of the cover) as are leads. Ridging is more common, with a maximum observed keel draft of 19.56 m. The overall mean ice thickness distribution has a peak at a draft of 1.05 m (1.18 m thickness), identified as the preferred draft of undeformed first‐year ice at this time. Ice draft and keel draft distributions followed a negative exponential distribution at depths beyond 3–4 m, and the distribution of lead widths followed a power law with exponent −2.29.