Japan Geoscience Union Meeting 2015

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International Session (Poster)

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

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

Tue. May 26, 2015 6:15 PM - 7:30 PM Convention Hall (2F)

Convener:*Huixin Liu(Earth and Planetary Science Division, Kyushu University SERC, Kyushu University), Yuichi Otsuka(Solar-Terrestrial Environment Laboratory, Nagoya University), Libo Liu(Institute of Geology and Geophysics, Chinese Academy of Sciences), Atsuki Shinbori(Research Institute for Sustainable Humanosphere (RISH), Kyoto University)

6:15 PM - 7:30 PM

[PEM06-P11] The relationship between the electric field in the lower atmosphere and Sq variations

*Akihiro IKEDA1, G. Maria Cardinal2 (1.Kagoshima National College of Technology, 2.International Center for Space Weather Science and Education)

Keywords:atomospheric electric field, Sq

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.