Physical Properties and Comparison of First- and Second-Year Sea Ice Ridges

Abstract

Five second-year sea ice ridges have been investigated in the Fram Strait in September 2008 for the third year. Cross sectional drillings were made with 2’’ augers in order to examine the geometry and the macroporosity of the ridges. The smallest and largest ones were respectively 3.94 m and 9 m deep. The macroporosity of the ridges was close to zero. Ice cores were sampled to establish temperature, salinity and density profiles and for further porosity calculations. Average ice density, salinity and porosity in the keel were found to be respectively 0.866 g/cm³, 2.7 psu and 18.6%. Similar investigations on a first-year sea ice ridge done in the Barents Sea in May 2008 showed that the same properties had higher values. Those ones were respectively 0.960 g/cm³, 4.46 psu and 22.7 %. The keel was 8.20 m deep at its maximum measured point. These results are used as inputs in numerical models and design codes.