研究者詳細 - 大山　伸一郎

論文 - 大山　伸一郎

分割表示 126 件中 81 - 100 件目／全件表示 >>

Lower thermospheric wind variations in auroral patches during the substorm recovery phase 査読有り Open Access

Shin-ichiro Oyama, Kazuo Shiokawa, Yoshizumi Miyoshi, Keisuke Hosokawa, Brenton J. Watkins, Junichi Kurihara, Takuo T. Tsuda andChristopher T. Fallen

J. Geophys. Res., Space Physics 121 巻 ( 4 ) 頁： 3564-3577 2016年5月

Relation between fine structure of energy spectra for pulsating aurora electrons and frequency spectra of whistler mode chorus waves 査読有り Open Access

Miyoshi, Y., S. Saito, K. Seki, T. Nishiyama, R. Kataoka, K. Asamura, Y. Katoh, Y. Ebihara, T. Sakanoi, M. Hirahara, S. Oyama, S. Kurita, and O. Santolik

J. Geophys. Res. Space Physics 2015年8月

A case study on generation mechanisms of a sporadic sodium layer above Tromsoe (69.6N) during a night of high auroral activity 査読有り Open Access

Takahashi, T., Nozawa, S., Tsuda, T. T., Ogawa, Y., Saito, N., Hidemori, T., Kawahara, T. D., Hall, C., Fujiwara, H., Matuura, N., Brekke, A., Tsutsumi, M., Wada, S., Kawabata, T., Oyama, S., and Fujii, R

Ann. Geophys. 2015年8月

Statistical study of auroral fragmentation into patches 査読有り Open Access

Hashimoto, A., K. Shiokawa, Y. Otsuka, S.-i. Oyama, S. Nozawa, T. Hori, M. Lester, and M. G. Johnsen

J. Geophys. Res. Space Physics 2015年7月

Energetic electron precipitation associated with pulsating aurora: EISCAT and Van Allen Probe observations 査読有り Open Access

Miyoshi, Y., S. Oyama, S. Saito, S. Kurita, H. Fujiwara, R. Kataoka, Y. Ebihara, C. Kletzing, G. Reeves, O. Santolik, M. Cliverd, C. J. Rodger, E. Turunen, and F. Tsuchiya

J. Geophys. Res. Space Physics 2015年3月

Approximate forms of daytime ionospheric conductance 査読有り Open Access

Ieda, A., S. Oyama, H. Vanhamäki, R. Fujii, A. Nakamizo, O. Amm, T. Hori, M. Takeda, G. Ueno, A. Yoshikawa, R. J. Redmon, W. F. Denig, Y. Kamide, and N. Nishitani

J. Geophys. Res. Space Physics 2014年11月

A case study of gravity wave dissipation in the polar MLT region using sodium LIDAR and radar data 査読有り Open Access

Takahashi, T., S. Nozawa, M. Tsutsumi, C. Hall, S. Suzuki, T. T. Tsuda, T. D. Kawahara, N. Saito, S. Oyama, S. Wada, T. Kawabata, H. Fujiwara, A. Brekke, A. Manson, C. Meek, and R. Fujii

Ann. Geophys. 2014年10月

Auroral fragmentation into patches 査読有り

Shiokawa, K., A. Hashimoto, T. Hori, K. Sakaguchi, Y. Ogawa, E. Donovan, E. Spanswick, M. Connors, Y. Otsuka, S. Oyama, S. Nozawa, and K. McWilliams

J. Geophys. Res. Space Physics 2014年9月

Height‐dependent ionospheric variations in the vicinity of nightside poleward expanding aurora after substorm onset 査読有り Open Access

Oyama, S., Y. Miyoshi, K. Shiokawa, J. Kurihara, T. T. Tsuda, and B. J. Watkins

119 巻 2014年5月

Decrease in sodium density observed during auroral particle precipitation over Tromsoe, Norway 査読有り Open Access

Tsuda, T., S. Nozawa, T. D. Kawahara, T. Kawabata, N. Saito, S. Wada, Y. Ogawa, S. Oyama, C. M. Hall, M. Tsutsumi, M. K. Ejiri, S. Suzuki, T. Takahashi, T. Nakamura

Geophys. Res. Let. 2013年8月

Observation of nighttime medium-scale travelling ionospheric disturbances by two 630-nm airglow imagers near the auroral zone 査読有り

Shiokawa, K., M. Mori, Y. Otsuka, S. Oyama, S. Nozawa, S. Suzuki, and M. Connors

J. Atmos. Solar-Terr. Phys. 2013年4月

Estimation of the layered ionospheric conductance using data from a multi-wavelength photometer at the European Incoherent Scatter (EISCAT) radar site 査読有り

Oyama, S., T. Watanabe, R. Fujii, S. Nozawa1, and T. T. Tsuda

Antarctic Record 57 巻 ( 3 ) 頁： 339-356 2013年

Development of low-cost sky-scanning Fabry-Perot interferometers for airglow and auroral studies 査読有り Open Access

Shiokawa, K., Y. Otsuka, S. Oyama, S. Nozawa, M. Satoh, Y. Katoh, Y. Hamaguchi, Y. Yamamoto, and J. Meriwether

Earth Planets Space 2012年11月

Motion of high-latitude nighttime medium-scale traveling ionospheric disturbances associated with auroral brightening 査読有り Open Access

Shiokawa, K., M. Mori, Y. Otsuka, S. Oyama, and S. Nozawa

J. Geophys. Res. 2012年10月

Mean winds, tides, and quasi-2 day waves above Bear Island 査読有り

Nozawa, S., C. M. Hall, M. Tsutsumi, A. Brekke, Y. Ogawa, T. T. Tsuda, S. Oyama, and R. Fujii

J. Atmos. Solar-Terr. Phys. 2012年5月

Temporal variations of the ion-neutral collision frequency from EISCAT observations in the polar lower ionosphere during periods of geomagnetic disturbances 査読有り Open Access

Oyama, S., J. Kurihara, B. J. Watkins, T. T. Tsuda, and T. Takahashi

J. Geophys. Res. 117 巻 ( A05308 ) 2012年3月

Generation of atmospheric gravity waves in the polar thermosphere in response to auroral activity 査読有り

Oyama, S., and B. J. Watkins

Space Science Review 2011年10月

Fine structure of sporadic sodium layer observed with a sodium lidar at Tromsoe, Norway 査読有り Open Access

Tsuda, T. T., S. Nozawa, T. Kawahara, T. Kawabata, N. Saito, S. Wada, C. Hall, S. Oyama, Y. Ogawa, S. Suzuki, T. Ogawa, T. Takahashi, H. Fujiwara, R. Fujii, N. Matuura, and A. Brekke

Geophys. Res. Lett. 2011年9月

Variance of the vertical ion speed measured with the EISCAT UHF radar in the polar lower ionosphere at Tromsoe, Norway 査読有り Open Access

Oyama, S., A. Brekke, T. T. Tsuda, J. Kurihara, and B. J. Watkins

J. Geophys. Res. 116 巻 ( A00K06 ) 2011年7月

Lower-thermospheric wind fluctuations measured with an FPI during pulsating aurora at Tromsø, Norway 査読有り Open Access

S. Oyama, K. Shiokawa, J. Kurihara, T. T. Tsuda, S. Nozawa, Y. Ogawa, Y. Otsuka, and B. J. Watkins

Ann. Geophysicae 28 巻頁： 1847-1857 2010年10月

記述言語：英語掲載種別：研究論文（学術雑誌）

Simultaneous observations were conducted with a Fabry-Perot Interferometer (FPI) at a wavelength of 557.7 nm, an all-sky camera at a wavelength of 557.7 nm, and the European Incoherent Scatter (EISCAT) UHF radar during the Dynamics and Energetics of the Lower Thermosphere in Aurora 2 (DELTA-2) campaign in January 2009. This paper concentrated on two events during periods of pulsating aurora. The lower-thermospheric wind velocity measured with the FPI showed obvious fluctuations in both vertical and horizontal components. Of particular interest is that the location of the fluctuations was found in a darker area that appeared within the pulsating aurora. During the same time period, the EISCAT radar observed sporadic enhancements in the F-region backscatter echo power, which suggests the presence of low-energy electron (1 keV or lower) precipitation coinciding with increase in amplitude of the electromagnetic wave (at the order of 10 Hz or higher). While we have not yet identified the dominant mechanism causing the fluctuations in FPI-derived wind velocity during the pulsating aurora, the frictional heating energy dissipated by the electric-field perturbations may be responsible for the increase in ionospheric thermal energy thus modifying the local wind dynamics in the lower thermosphere.

DOI： 10.5194/angeo-28-1847-2010

Open Access

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