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