Japan Geoscience Union Meeting 2015

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International Session (Oral)

Symbol P (Space and Planetary Sciences) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM07] Space Weather, Space Climate, and VarSITI

Sun. May 24, 2015 4:15 PM - 6:00 PM 302 (3F)

Convener:*Ryuho Kataoka(National Institute of Polar Research), Yusuke Ebihara(Research Institute for Sustainable Humanosphere, Kyoto University), Yoshizumi Miyoshi(Solar-Terrestrial Environement Laboratory, Nagoya University), Toshifumi Shimizu(Institute of Space and Astronautical Science, JAXA), Ayumi Asai(Unit for Synergetic Studies of Space, Kyoto University), Hidekatsu Jin(National Institude of Information and Communications Technology), Tatsuhiko Sato(Japan Atomic Energy Agency), Kanya Kusano(Solar-Terrestrial Environment Laboratory, Nagoya University), Hiroko Miyahara(College of Art and Design, Musashino Art University), Takuji Nakamura(National Institute of Polar Research), Kazuo Shiokawa(Solar-Terrestrial Environment Laboratory, Nagoya University), Kiminori Itoh(Graduate School of Engineering, Yokohama National University), Chair:Yusuke Ebihara(Research Institute for Sustainable Humanosphere, Kyoto University)

4:45 PM - 5:00 PM

[PEM07-02] Climatology of the polar thermosphere and ionosphere

*Hitoshi FUJIWARA1, Yasunobu MIYOSHI2, Hidekatsu JIN3, Hiroyuki SHINAGAWA3, Satonori NOZAWA4, Yasunobu OGAWA5, Ryuho KATAOKA5 (1.Faculty of Science and Technology, Seikei University, 2.Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, 3.National Institute of Information and Communications Technology, 4.Solar Terrestrial Environment Laboratory, Nagoya University, 5.National Institute of Polar Research)

Keywords:thermosphere, ionosphere, polar region, EISCAT, GCM, simulation

Recent observations from satellites and ground-based instruments have clarified various phenomena in the polar thermosphere and ionosphere, in particular, the cusp and polar cap region. The CHAMP satellite observations for a decade were the great success to understand the mass density variations in the global thermosphere. However, some basic features and/or climatology of the polar thermosphere and ionosphere seem to be still unknown. For example, amplitudes of the temperature and wind variations during a solar cycle are not exactly known in the local area in and/or in the vicinity of the cusp/polar cap region. In addition, contributions of the lower atmosphere to the temperature and wind variations in the thermosphere seem not to be understood quantitatively in each local area. In order to understand climatology of the polar thermosphere and ionosphere, we have made some observations with the EISCAT radar system and optical instruments in 2011-2015 and performed numerical simulations with a whole atmosphere GCM. The five-year observations of the polar ionosphere with the EISCAT radar system show the large difference between the ionospheres over Longyearbyen and Tromsoe; variations of the dayside ion temperature and ion motion at Longyearbyen are larger than those at Tromsoe on average during geomagnetically quiet periods. The EISCAT data during the extremely low solar activity 2007-2008 have also clarified the basic state of the ionosphere which would be strongly affected by the lower atmosphere. We will show the recent progress of our understandings of basic features of the polar thermosphere and ionosphere from the observations and GCM simulations.