1. Exploration Physics International, Inc., Huntsville, Alabama 35806
2. National Oceanic and Atmospheric Administration, Boulder, Colorado 80305
3. University of Alaska, Fairbanks, Alaska 99775
4. Institut d’Estudis Espacials de Catalunya, E-08034 Barcelona, Spain
5. Johns Hopkins University, Applied Physics Laboratory, Laurel, Maryland 20723
6. Universitat de Barcelona, E-08028 Barcelona, Spain
7. University of Alaska, Fairbanks, Alaska 99773