Ice ridges in landfast ice of Shokal'skogo Strait

Abstract

Three first-year ice ridges have been examined with respect to geometry and morphology in landfast ice of Shokal'skogo Strait (Severnaya Zemlya Archipelago) in May 2018. Two of the studied ice ridges were located on the edge of the ridged field and were part of it, because their keels extended for a long distance deep into this field. Ice ridges characteristics are discussed in the paper. These studies were conducted using hot water thermal drilling with computer recording of the penetration rate. Boreholes were drilled along the cross-section of the ridge crest at 0.25 m intervals. Cross-sectional profiles of ice ridges are illustrated. The maximal sail height varied from 2.9 up to 3.2 m, the maximal keel depth varied from 8.5 up to 9.6 m. The average keel depth to sail height ratio varied from 2.8 to 3.3, and the thickness of the consolidated layer was 2.5-3.5 m. The porosity of the non-consolidated part of the keel was about 23-27%. The distributions of porosity versus depth for all ice ridges are presented.

Linking sea ice deformation to ice thickness redistribution using high-resolution satellite and airborne observations

“…First, our model does not account for the high macroporosity of unconsolidated FYI ridge keels, which leads to an underestimation of the thickness. Numerous studies have shown that mean ridge porosities amount to 11 %-22 % (Kharitonov and Borodkin, 2020;Kharitonov, 2019a, b;Strub-Klein and Sudom, 2012), with the largest range between 11 % and 45 % for old FYI ridges and newly formed FYI ridges, respectively (Ervik et al, 2018;Høyland, 2007). If we assume that the fraction of 86 % of deformed ice in all observations had a porosity of 11 %-22 %, the mean modeled thickness will increase by 0.1-0.3 m, to 1.8-2 m. In the context of porosity, we also discuss the uncertainties in the EM ice thickness measurements.…”