1. Scientific Aviation, 3335 Airport Road, Boulder, CO 80301, USA.
2. Department of Land, Air, and Water Resources, University of California–Davis, Davis, CA 95616, USA.
3. Research and Development Division, California Energy Commission, Sacramento, CA 95814, USA.
4. Department of Chemistry, University of California–Irvine, Irvine, CA 92617, USA.
5. Cooperative Institute for Research in Environmental Sciences, University of Colorado–Boulder, Boulder, CO, 80309, USA.
6. Earth System Research Laboratory, National Oceanic and Atmospheric Administration (NOAA), Boulder, CO, 80305, USA.