Internal structure and porosity of ice ridges investigated at «North Pole‐38» drifting station

The paper presents the investigation results of morphometric characteristics of three first-year ice ridges conducted in March–June 2011 at «North Pole‐38» drifting station. The height of the ice ridge sail ranged within 3.3–6.1 m; keel draft, from 10.2 to 18.9 m. These studies were conducted using electric thermal drilling with computer recording of the penetration rate. Boreholes were drilled along the cross‐section of the ridge crest at 0.5 m intervals. Cross-sectional profiles of ice ridges are illustrated. In each borehole, ice ridge porosity was calculated as the ratio of the length of all voids to total length of the borehole. Distribution of ice ridge porosity along the cross-section seems to be rather regular. Depth-wise distribution of volume content of solid ice phase is shown for the investigated ice ridges. Average thickness of consolidated layer of ice ridges ranged within 0.8 … 2.6 m.