*Vigan Mensah¹、Yoshihiro Nakayama^1,2、Masakazu Fujii⁴、Kay I. Ohshima^1,3 (1.Institute of Low Temperature Science, Hokkaido University、2.Engineering Faculty, Dartmouth College, NH, U.S.A、3.Arctic Research Center, Hokkaido University、4.National Institute of Polar Research)