1. Geophysical Institute University of Alaska Fairbanks Fairbanks AK USA
2. Department of Electrical and Computer Engineering and Center for Space Sciences Boston University Boston MA USA
3. Space Science Institute Boulder CO USA
4. Department of Atmospheric and Oceanic Sciences University of California, Los Angeles Los Angeles CA USA
5. SRI International Menlo Park CA USA
6. Department of Earth, Planetary, and Space Sciences University of California, Los Angeles Los Angeles CA USA