日本地球惑星科学連合2015年大会

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インターナショナルセッション(ポスター発表)

セッション記号 P (宇宙惑星科学) » P-EM 太陽地球系科学・宇宙電磁気学・宇宙環境

[P-EM06] Mesosphere-Thermosphere-Ionosphere Coupling in the Earth's Atmosphere

2015年5月26日(火) 18:15 〜 19:30 コンベンションホール (2F)

コンビーナ:*Huixin Liu(九州大学理学研究院地球惑星科学専攻 九州大学宙空環境研究センター)、大塚 雄一(名古屋大学太陽地球環境研究所)、Libo Liu(Institute of Geology and Geophysics, Chinese Academy of Sciences)、新堀 淳樹(京都大学生存圏研究所)

18:15 〜 19:30

[PEM06-P11] 大気電場と地磁気日変化の関連

*池田 昭大1G. Maria Cardinal2 (1.鹿児島工業高等専門学校、2.国際宇宙天気科学・教育センター)

キーワード:大気電場, 地上磁場

The vertical atmospheric electric field (Ez) variations depend on the state of the global electric circuit. Geomagnetic phenomena can influence Ez through ionospheric disturbances [e.g. Kleimenova, 2008]. The daily quiet geomagnetic field variations (Sq variations) are mainly caused by electric field currents flowing in the E region of the ionosphere. It is likely that Sq variations are relevant to Ez variations. In this study, we aim to investigate the relationship between Ez and Sq variations at a low-latitude station. We analyzed the Ez and ground magnetic field data (H) at KAK (G.G. Lat.: 36.2 N, G.G. Lon.: 140.2 E) station during 2006 - 2014. The data was provided by the Kakioka Magnetic Observatory of the Japan Meteorological Agency. In here, we adopt the same definition for Sq amplitudes as defined by Yamazaki et al. [2010]. The daily amplitude of the Sq variation is derived by subtracting nighttime (22-24 LT and 00-02 LT) H values from daytime H (peak) values. Similarly, we calculated the daily Ez variation. The daytime Ez values were selected at the time when daytime H values show their peaks. The obtained Sq and Ez variations show annual and semi-annual variations. The annual variations are clearly seen every year, becoming the smaller values in winter. The semi-annual variations in Ez are clear in 2011 and 2014. As just described, we found similarities between Sq and Ez variations in several respects and ,therefore, conclude that the Ez variations depend on the condition of the ionosphere.