1. Graduate School of Communication Engineering and Informatics University of Electro‐ Communications Chofu Tokyo Japan
2. Institute for Space‐Earth Environmental Research Nagoya University Nagoya Aichi Japan
3. National Institute of Polar Research Tachikawa Tokyo Japan
4. University of Oulu Oulu Finland
5. Research Institute for Sustainable Humanosphere Kyoto University Uji Kyoto Japan
6. Graduate School of Natural Science and Technology Kanazawa University Kanazawa Ishikawa Japan
7. Department of Geophysics Graduate School of Science Tohoku University Sendai Miyagi Japan
8. Institute of Space and Astronautical Science Sagamihara Kanagawa Japan
9. Research Organization of Information and Systems Minato‐ku Tokyo Japan