Ayako Abe-Ouchi, University of Tokyo, Atmosphere and Ocean Research Institute, Bunkyo-ku, Japan, Wing-Le Chan, University of Tokyo, Tokyo, Japan, Takashi Obase, University of Tokyo, Atmosphere and Ocean Research Institute, Kashiwa, Japan, Sam Sherriff-Tadano, Atmosphere and Ocean Research Institute University of Tokyo, Tokyo, Japan, Takahito Mitsui, University of Tokyo, Kashiwa, Japan, Kenji Kawamura, Natl. Inst. of Polar Research, Tokyo, Japan, Masakazu Yoshimori, The University of Tokyo, Chiba, Japan, Akira Oka, University of Tokyo, Bunkyo-ku, Japan, Christo Buizert, Oregon State University, College of Earth, Ocean, and Atmospheric Sciences, Corvallis, OR, United States, Stephen Obrochta, Akita University, Graduate School of International Resource Science, Akita, Japan and Rumi Ohgaito, JAMSTEC Japan Agency for Marine-Earth Science and Technology, Kanagawa, Japan