[1] NOAA, Solar Terr Phys Div, Natl Geophys Data Ctr, Boulder, CO 80303 USA
[2] Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA
[3] Colorado State Univ, Cooperat Inst Res Atmosphere, Ft Collins, CO 80523 USA
[4] Northrop Grumman Corp, Elect Sensors & Syst Div, Baltimore, MD USA
[5] Univ Calif Santa Barbara, Dept Geog, Santa Barbara, CA 93106 USA