Ronald G Prinn¹, Jian-Xiong Sheng¹, Christina M Harth², Paul B Krummel³, Chris R Lunder⁴, Jens Muhle⁵, Simon Joseph Odoherty⁶, Peter Salameh⁷, Ray F Weiss⁸, Dickon Young⁹, Patrick Sheese¹⁰ and Kaley A Walker¹⁰, (1)Massachusetts Institute of Technology, Cambridge, MA, United States, (2)University of California San Diego, Scripps Institution of Oceanography, La Jolla, CA, United States, (3)CSIRO, Aspendale, Australia, (4)Norwegian Institute for Air Research, Kjeller, Norway, (5)Scripps Institution of Oceanography, La Jolla, CA, United States, (6)University of Bristol, Bristol, United Kingdom, (7)Scripps Institution of Oceanography, Carlsbad, CA, United States, (8)Univ California San Diego, La Jolla, CA, United States, (9)University of Bristol, School of Chemistry, Bristol, United Kingdom, (10)University of Toronto, Department of Physics, Toronto, ON, Canada