1. Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
2. Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, Colorado 80305, United States
3. Global Systems Division, NOAA Earth System Research Laboratory, Boulder, Colorado 80305, United States
4. Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, United States
5. Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, United States
6. Joint Center for Earth Systems Technology, University of Maryland Baltimore County, Baltimore, Maryland 21228, United States