Barbara K Dix¹, Joep de Bruin², Mikhail N Zhizhin³, Colby Francoeur⁴, Tim Vlemmix⁵, Pepijn Veefkind^5,6, Christopher Elvidge⁷, Brian C McDonald^8,9, Pieternel Levelt^2,10 and Joost A de Gouw^11,12, (1)University of Colorado at Boulder, CIRES, Boulder, CO, United States, (2)Delft University of Technology, Delft, Netherlands, (3)NGDC NOAA, Boulder, CO, United States, (4)University of Colorado, Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States, (5)Technical University Delft, Delft, Netherlands, (6)Royal Netherlands Meteorological Institute, De Bilt, Netherlands, (7)Colorado School of Mines, Payne Institute for Public Policy, Golden, CO, United States, (8)Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, United States, (9)Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, United States, (10)Royal Netherlands Meteorological Instiute, De Bilt, Netherlands, (11)CIRES, Boulder, CO, United States, (12)University of Colorado Boulder, Boulder, CO, United States