*Kazutoshi Sato¹, Jun Inoue^1,2,3, Akira Yamazaki², Joo-hong Kim⁴, Marion Maturilli⁵, Klaus Dethloff⁵, Stephen R Hudson⁶ (1.National Institute of Polar Research, 2.Japan Agency for Marine-Earth Science and Technology, 3.SOKENDAI (Graduate University for Advanced Studies), 4.Korea Polar Research Institute, 5.Alfred Wegener Institute, 6.Norwegian Polar Institute)