• Journal of the Society of Naval Architects of Korea
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• v.49 no.2
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• pp.189-195
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• 2012

The ice trials of the first Korean icebreaking research vessel "ARAON" were performed at the Arctic Ocean in July-August 2010. The sea ice concentrations of Arctic Ocean were 4/10 to 10/10 and the range of sea ice thickness was roughly 1.0 to 3.5m. In this research, sea ice thickness characteristics at the old ice floes were determined from results of drill hole and apparent conductivity measurements. Especially we measured apparent conductivity using an electromagnetic induction instrument (EM31-MK2) and estimated the sea ice thickness through the empirical equation from Cold Regions Research & Engineering Laboratory, CRREL. The results of estimated sea ice thickness were compared to drill hole measurement results and then, we suggest the new empirical equation to estimate sea ice thickness of single layer type sea ice during the summer season of Arctic Ocean by curve fitting approach to these data.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.3
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• pp.134-144
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• 2009

Paleoproductivity changes in the central part of the Bering Sea since the last glacial period were reconstructed by analyzing opal and total organic carbon (TOC) content and their mass accumulation rate (MAR) in sediment core PC23A. Ages of the sediment were determined by both AMS $^{14}C$ dates using planktonic foraminifera and Last Appearance Datum of radiolaria (L. nipponica sakaii). The core-bottom age was calculated to reach back to 61,000 yr BP. and some of core-top was missing. Opal and TOC contents during the last glacial period varied in a range of 1-10% and 0.2-1.0%, and their average values are 5% and 0.7%, respectively. In contrast, during the last deglaciation, opal and TOC contents varied from 5 to 22% and from 0.8 to 1.2%, respectively, with increasing average values of 8% and 1.0%. Opal and TOC MAR were low ($1gcm^{-2}kyr^{-1}$, $0.2gcm^{-2}kyr^{-1}$) during the last glacial period, but they increased (>5 and >$1gcm^{-2}kyr^{-1}$) during the last deglaciation. High diatom productivity during the last deglaciation was most likely attributed to the elevated nutrient supply to the sea surface resulting from increased melt water input from the nearby land and enhanced Alaskan Stream injection from the south under the restricted sea-ice and warm condition during the rising sea level. On the contrary, low productivity during the last glacial period was mainly due to decreased Alaskan Stream injection during the low sea-level condition as well as to extensive development of sea ice under low-temperature seawater and cold environment.