1. Department of Meteorology; Pennsylvania State University; University Park Pennsylvania USA
2. Goddard Space Flight Center; Greenbelt Maryland USA
3. Department of Chemistry; University of Oslo; Oslo Norway
4. Institute for Ion Physics and Applied Physics; University of Innsbruck; Innsbruck Austria
5. Department of Chemistry; University of California at Irvine; Irvine California USA
6. Atmospheric Chemistry Observations and Modeling Laboratory; National Center for Atmospheric Research; Boulder Colorado USA