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Ann. Geophys., 23, 2385-2390, 2005
www.ann-geophys.net/23/2385/2005/
© European Geosciences Union 2005
Relationship between propagation direction of gravity waves in OH and OI airglow images and VHF radar echo occurrence during the SEEK-2 campaign
F. Onoma1,*, Y. Otsuka1, K. Shiokawa1, T. Ogawa1, M. Yamamoto2, S. Fukao2, and S. Saito3
1Solar-Terrestrial Environment Laboratory, Nagoya University, Honohara 3-13, Toyokawa, Aichi 442-8507, Japan
2Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
3National Inst. of Information and Communications Technology, 4-2-1 Nukui-Kitamachi, Koganei, Tokyo 184-8795, Japan
*now at: Mitsubishi Electric Corp., Chiyoda-ku, Tokyo 100-8310, Japan
Abstract. We report simultaneous observations of atmospheric gravity waves (AGW)
in OI (557.7nm) and OH airglow images and VHF radar backscatter
from field-aligned irregularities (FAI) in the E-region
during the SEEK-2 (Sporadic-E Experiment over Kyushu 2) campaign
period from 29 July to 9 August 2002.
An all-sky imager was operated at Nishino-Omote
(30.5 N, 130.1 E), Japan.
On 14 nights,
17 AGW events were detected in OI and OH airglow images.
AGW propagated mostly toward the northeast or southeast.
From comparison with the E-region FAI occurrence,
which is detected by a nearby VHF radar (31.57MHz),
we found that AGW tended to propagate southeastward during FAI events.
This result suggests that the interaction between AGW and E-region
plasma plays an important role in generating FAI.
Furthermore,
polarization electric fields generated directly by AGW
may contribute to the FAI generation.
Keywords. Atmospheric composition and structure (Airglow
and aurora), Ionosphere (Ionospheric irregularities,
Mid-latitude ionosphere)
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