Xin Lin, University of Michigan Ann Arbor, Ann Arbor, MI, United States, Gretchen Keppel-Aleks, University of Michigan Ann Arbor, Climate and Space Sciences and Engineering, Ann Arbor, MI, United States, Brendan M Rogers, Woods Hole Science Center Falmouth, Falmouth, MA, United States, Colm Sweeney, NOAA ESRL, Global Monitoring Division, Boulder, CO, United States, Mikhail Arshinov, Russian Academy of Sciences, V. E. Zuev Institute of Atmospheric Optics, Tomsk, Russia, Edward J Dlugokencky, NOAA/ESRL Global Monitoring Division, Boulder, CO, United States, Toshinobu Machida, Natl Inst Environal Studies, Tsukuba, Japan, Motoki Sasakawa, NIES, Tsukuba, Japan and Pieter P Tans, NOAA, ESRL/GMD, Boulder, CO, United States