Dale F Hurst^1,2, Karen Hepler Rosenlof³, Sean M Davis³, Amy H Butler^1,3, William G Read⁴, Emrys Hall^1,2 and Allen F Jordan^1,2, (1)Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, United States, (2)Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, CO, United States, (3)Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, United States, (4)NASA Jet Propulsion Laboratory, Pasadena, CA, United States