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

Abstract

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.

Thickness distribution, texture and stratigraphy, and a simple probabilistic model for dynamical thickening of sea ice in the southern Sea of Okhotsk

“…However, the observations have been done mainly for perennial or seasonal/thick ice regions. As for the MIZ, Wadhams et al [1985], for example, showed the characteristics of the ice thickness distribution from submarine sonar data in the MIZ of Davis Strait. Worby et al [1996] obtained ice thickness data from ship‐based visual observations near the Antarctic.…”

On the spacing and draft distributions for pressure ridge keels

“…For sonar profiles it is usual to replace the local level ice draft by some arbitrary depth for ease of computing. In the Arctic Basin it has usually been taken as 2.5 m [Williams et al, 1975;Wadhams, 1978Wadhams, , 1980Wadhams, , 1981McLaren et al, 1984;Wadhams and Horne, 1980], although for the Davis Strait a 1-m criterion has been used [Wadhams et al, 1985] on account of the thin level first-year ice found there.…”

Characterization of springtime leads in the Beaufort/Chukchi Seas from airborne and satellite observations during FIRE/SHEBA

“…Typically, arctic leads form long, narrow channels that are tens to hundreds of meters wide and kilometers long. Leads are more prevalent in areas of thin ice, including the marginal ice zones, than in the central Arctic ice pack [ Wadhams et al , 1985]. Leads are responsible for about 50% of the sensible heat transfer from the Arctic Ocean to the atmosphere during winter [ Maykut , 1982], although they cover only a few percent of the surface area.…”