[1] Univ Michigan, Dept Climate & Space Sci & Engn, Ann Arbor, MI 48109 USA
[2] US Naval Res Lab, Washington, DC USA
[3] Univ Nacl Autonoma Mexico, Inst Geophys, Mexico City, Mexico
[4] Northumbria Univ, Dept Math Phys & Elect Engn, Newcastle Upon Tyne, England
[5] Goddard Space Flight Ctr, Greenbelt, MD USA
[6] Catholic Univ Amer, Dept Phys, Washington, DC USA