Japan Geoscience Union Meeting 2014

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International Session (Oral)

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

[P-EM06_30PM2] Study of coupling processes in Sun-Earth system with large radars and large-area observations

Wed. Apr 30, 2014 4:15 PM - 6:00 PM 312 (3F)

Convener:*Mamoru Yamamoto(Research Institute for Sustainable Humanosphere, Kyoto University), Yasunobu Ogawa(National Institute of Polar Research), Satonori Nozawa(Solar-Terrestrial Environment Laboratory), Hiroyuki Hashiguchi(Research Institute for Sustainable Humanosphere, Kyoto University), Chair:Hiroyuki Hashiguchi(Research Institute for Sustainable Humanosphere, Kyoto University)

5:15 PM - 5:30 PM

[PEM06-P03_PG] Statistical study of F-region field-aligned irregularities based on Equatorial Atmosphere Radar in Indonesia

3-min talk in an oral session

*Tam DAO1, Yuichi OTSUKA1, Kazuo SHIOKAWA1, Mamoru YAMAMOTO2 (1.STEL, Graduate School of Science, Nagoya University, 2.Research Institute for Sustainable Humanosphere, Kyoto University)

Keywords:F-region Ionosphere, Field-Aligned Irregularities (FAIs), VHF radar

I examined the statistical characteristics of Field-Aligned Irregularities (FAIs) echoes from the F-region of Ionosphere using Equatorial Atmosphere Radar (EAR) in Indonesia during three years from 2010 to 2012. We investigated the differences between post-sunset and post-midnight FAIs. Some results are analyzed in the daily and monthly average of echo power, spectral width, and Doppler velocity. We found that post-midnight FAIs occurred mostly in summer solstices from May to August in 2010 and 2011, and only in June and July in 2012. We realized some different characteristics between post-sunset and post-midnight FAIs observed from EAR as follow. (1) Echo intensity of the post-midnight FAIs is weaker than that of post-sunset FAIs. (2) The post-sunset FAIs often exceed an altitude of 450 km, whereas the post-midnight FAIs mostly occur in a range from 200 to 450 km in F-region. (3) Spectral width of the post-midnight FAIs is smaller than that of the post-sunset FAIs. These results suggest that plasma instability operates more actively at post-sunset than at post-midnight.