1. Solar‐Terrestrial Environment LaboratoryNagoya University Nagoya Japan
2. Finnish Meteorological Institute Helsinki Finland
3. Department of PhysicsUniversity of Oulu Oulu Finland
4. National Institute of Information and Communications Technology Koganei Japan
5. Data Analysis Center for Geomagnetism and Space Magnetism, Graduate School of ScienceKyoto University Kyoto Japan
6. Institute of Statistical MathematicsROIS Tachikawa Japan
7. Department of Earth and Planetary SciencesKyushu University Fukuoka Japan
8. National Geophysical Data CenterNOAA Boulder Colorado USA