1. High Altitude Observatory; National Center for Atmospheric Research; Boulder Colorado USA
2. Geophysical Institute; University of Alaska; Fairbanks Alaska USA
3. Applied Physics Laboratory; Johns Hopkins University; Laurel Maryland USA
4. Danish Meteorological Institute; Copenhagen Denmark
5. Arctic and Antarctic Research Institute; St. Petersburg Russia
6. Earth and Space Sciences Department; University of Washington; Seattle Washington USA
7. Space Sciences Laboratory; University of California; Berkeley California USA