元データ 国立極地研究所


Two ice cores (83.92 m and 24.41 m depth) were obtained at one of the highest areas in northwestern Spitsbergen in Svalbard (Snφfjellafonna) by the Japanese Arctic Glaciological Expedition 1992,with cooperation from the Norwegian Polar Research Institute. Water samples were prepared for chemical and biological analyses at 15 cm intervals from the surface to 44.14 m depth in the 83.92 m ice core. The rest of the ice cores were stored in a cold room at Ny-Alesund, Svalbard. Tritium concentration of the 83.92 m ice core was continuously measured from 16.87 m depth to 28.195 m depth at 15cm intervals. The highest peak of the Tritium concentration was found in the depth range between 20.49m and 20.635m. This layer probably corresponds to the 1963 layer which is known to be the highest peak layer of the Tritium concentration in the Greenland Ice Sheet. The mean annual accumulation rate above the 1963 layer was calculated to be 0.48 m/year in water equivalent. Electrical conductivity (EC) of the same ice core was also measured at the same interval from the surface to 44.14 m depth. 31 major peaks of EC were observed from the surface to the 1963 layer (20.635 m depth), which corresponds to 0.45 m/peak in water equivalent. Thus, most of the peaks are probably identical with annual layer boundaries at which ions in firn/ice are concentrated. 25 major peaks of EC were observed from 20.64m to 44.14m depth. Assuming that the 56 (=31+25) peaks of EC are annual layer boundaries, the ice at 44.14m depth should have been deposited in the mid-1930s.


幸島 司郎 京大
Watanabe Okitsugu National Institute of Polar Research, Research Organization of Information and Systems
Izumi Kaoru Research Center for Natural Hazards & Disaster Recovery, Niigata University
Izumi K Research Center For Natural Hazards & Disaster Recovery Niigata University
Takahashi Shuhei Kitami Institute of Technology
Kameda Takao Kitami Institute of Technology
Shiraiwa T Disaster Prevention Research Institute Kyoto University
Watanabe Okitsugu National Institute Of Polar Research
Saito T Institute Of Low Temperature Science Hokkaido University
Azuma Kumiko National Institute of Polar Research
Azuma Kumiko Nagaoka Institute Of Snow And Ice Studies National Research Institute For Earth Science And Disaster
Kohshima S Faculty Of Bioscience And Biotechnology C
辛島 司郎 東京工業大学生命理工学部
Kohshima Shiro Biological Laboratory Faculty Of Science Tokyo Institute Of Technology
Kohshima Shiro Biological Laboratory Faculty Of Bioscience And Biotechnology Tokyo Institute Of Technology
Kohshima Shiro Tokyo Institute Of Technology
辛島 司郎 東京工業大学大学院生命理工学研究科
Izumi Kaoru Research Institute For Hazards In Snowy Areas Niigata University
HAGEN Jon Norwegian Polar Research Institute
Takahashi Shuhei Department Of Civil Engineering Kitami Institute Of Technology
幸島 司郎 東京工業大学
Kawamura Toshiyuki Department Of Applied Physics Faculty Of Engineering Hokkaido University:(present Address)institute
Kobayashi Shin'ichi Research Institute Of Hazards In Snowy Areas Niigata University