Estimating the thickness of sea ice

TLDR

The authors measured freeboard, thickness, and snow depth at closely spaced drill sites on five multiyear ice floes, performed regressions of ice thickness on draft (with and without pressure‑ridge screening), and derived a predictive equation t = 1.115 d to estimate total thickness from draft. They found the keel‑sail height ratio for pressure ridges to be consistently 3.3 : 1, matching previous observations.

Abstract

Sea ice freeboard, thickness, and snow depth were measured from a series of closely spaced (5 to 10 m) drill hole sites from five free‐floating multiyear ice floes in the Beaufort Sea during the spring of 1986 and 1987. A regression of ice thickness on ice draft was performed on the data from each floe and for the combined data set. Regressions were performed both on nonscreened data and data screened to eliminate pressure ridges. A predictive equation was developed permitting the total ice thickness to be estimated from measured values of ice draft, e.g., from submarine echo sounder traces: t = 1.115 d . The keel‐sail height ratio for pressure ridges was found constant at 3.3 to 1, in agreement with past observations.