1. Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
2. School of Earth and Space Sciences; Peking University; Beijing China
3. Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
4. Department of Physics and Astronomy; University of California; Los Angeles California USA
5. Center for Atmospheric Research; University of Massachusetts; Lowell Massachusetts USA
6. Space Science Laboratory; University of California; Berkeley California USA
7. Institute for Geophysics and Extraterrestrial Physics; TU Braunschweig; Braunschweig Germany