1. Goddard Earth Sciences
Technology and Research, Universities Space Research Association, Columbia, Maryland 21044-3432,
United States
2. NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, United States
3. Department of Physics
and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
4. Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138,
United States
5. Chemical Sciences
Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder,
Colorado 80305, United States