*Prabir Patra^1,2, Tazu Saeki¹, Edward J Dlugokencky⁴, Kentaro Ishijima¹, Taku Umezawa³, Akihiko Ito³, Shuji Aoki², Shinji Morimoto², Eric A Kort⁵, Andrew Crotwell⁴, Ravi Kumar Kunchala⁶, Takakiyo Nakazawa² (1.Department of Environmental Geochemical Cycle Research, JAMSTEC, Yokohama, Japan, 2.CAOS, Graduate School of Science, Tohoku University, Sendai, Japan, 3.National Institute for Environmental Studies, Tsukuba, Japan, 4.NOAA Earth System Research Laboratory, Colorado, USA, 5.University of Michigan, Michigan, USA, 6.Arctic GRENE, National Institute of Polar Research, Tachikawa, Japan)

*Yosuke Niwa¹, Yousuke Sawa¹, Toshinobu Machida², Hidekazu Matsueda¹, Taku Umezawa², Nobuko Saigusa² (1.Meteorological Research Institute, 2.National Institute for Environmental Studies)

*Taku Umezawa¹, Hidekazu Matsueda², Toshinobu Machida¹, Yousuke Sawa², Yosuke Niwa² (1.National Institute for Environmental Studies, 2.Meteorological Research Institute)

*Taku Umezawa¹, Yosuke Niwa², Yousuke Sawa², Toshinobu Machida¹, Hidekazu Matsueda² (1.National Institute for Environmental Studies, 2.Meteorological Research Institute)