The full-scale ice trials of the first Korean icebreaker “ARAON” were conducted at the Arctic Ocean in July-August 2010. Sea ice concentrations of Arctic sea were 4/10 to 10/10 and sea ice thicknesses were roughly 1.0 to 3.5m. In this research, the sea ice thickness distributions at the ice floe were determined from results of drilling and electromagnetic induction instrument, EM31-MK2. Especially we measured apparent conductivity on the ice floe using the EM31-MK2 and estimated the sea ice thickness by using the empirical formula from Cold Regions Research & Engineering Laboratory, CRREL. The results of sea ice thickness derived with the EM31-MK2 were compared to observations results and then, we suggest the new empirical formula for estimation of sea ice thickness through the analysis of apparent conductivity data.
The former kind of researches for sea ice thickness measurements with electromagnetic instrument were performed in Arctic and Antarctic (Hass et al., 1997 and 2006; Jones et al., 2001; Kovacs and Morey, 1991; Tateyama et al., 2004 and 2006). The main purpose of the first Arctic voyage of the first Korean icebreaker “ARAON” was to carry out the measurement of sea ice thickness and icebreaking performance evaluation. In this paper, we mainly investigate ice thickness distribution in the northern Chukchi Sea and Beaufort Sea for the summer of 2010. During the 2010 ARAON cruise, ice thickness was determined from data of ice drilling and EM Induction instrument, total four ice field tests were performed along the ship’s cruise tracks. We measured measuring distance, coordinate, ice thickness, snow depth and freeboard. When we use EM induction instrument, we measure EM height from ice surface to EM induction instrument and apparent conductivity. The general principle of EM to estimate sea ice thickness is simpler than ice drilling.