1. Department of Earth, Ocean and Atmospheric Sciences; University of British Columbia; Vancouver British Columbia Canada
2. The Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
3. Planetary Science Institute; Tucson Arizona USA
4. Department of Atmospheric, Oceanic and Space Sciences; University of Michigan; Ann Arbor Michigan USA
5. NASA Goddard Space Flight Center; Greenbelt Maryland USA
6. Laboratory for Atmospheric and Space Physics; University of Colorado; Boulder Colorado USA
7. Department of Terrestrial Magnetism; Carnegie Institution of Washington; Washington D. C. USA
8. Lamont-Doherty Earth Observatory; Columbia University; Palisades New York USA