Stephen A Montzka¹, Geoffrey S Dutton², Eric A Ray³, Robert W Portmann⁴, Brad David Hall¹, Matthew L Rigby⁵, Alistair Manning⁶ and James W Elkins¹, (1)NOAA/ESRL GMD, Boulder, CO, United States, (2)Cooperative Institute for Research in Environmental Sciences, NOAA/ESRL Global Monitoring Division, Boulder, CO, United States, (3)Cooperative Institute for Research in Environmental Sciences, NOAA Chemical Sciences Division, Boulder, CO, United States, (4)Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, United States, (5)University of Bristol, Bristol, United Kingdom, (6)UK Meteorological Office, Climate Research, Exeter, United Kingdom