1. High Altitude ObservatoryNational Center for Atmospheric Research Boulder Colorado USA
2. Division of Polar Climate ChangeKorea Polar Research Institute Incheon South Korea
3. Department of Astronomy, Space Science, and GeologyChungnam National University Daejeon South Korea
4. Department of PhysicsUniversity of New Brunswick Fredericton New Brunswick Canada
5. Center for Geospace StudiesSRI international Menlo Park California USA