On the results of studying ice ridges in the Shokal'skogo Strait, part II: Porosity

Abstract

The paper describes the morphometric characteristics of three first-year ice ridges investigated in April and May 2016 in the Shokal'skogo Strait (Severnaya Zemlya Archipelago). 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 mainly at 0.25 m intervals. The main results of the ice ridges studies are given in Part I. Cross-sectional profiles of ice ridges are illustrated. In each borehole, porosity of an ice ridge was calculated as the ratio of the length of all voids to total length of the borehole. Processing of the results showed that when studying ice ridges for obtaining the porosity values close to the true ones, the boreholes should be drilled with a spacing not exceeding two meters. Away from the point where the keel has the maximum draft, the average porosity of the unconsolidated part of the keel tends to increase. This feature is a consequence of the effect of the Archimedes force and agrees with the model of porosity changes from the theory of granular media.