研究者詳細 - 大塚　雄一

論文 - 大塚　雄一

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Airglow observations of nighttime medium-scale traveling ionospheric disturbances from Yonaguni: Statistical characteristics and low-latitude limit 査読有り

Narayanan, VL; Shiokawa, K; Otsuka, Y; Saito, S

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 119 巻 ( 11 ) 頁： 9268 - 9282 2014年11月

First spaceborne observation of the entire concentric airglow structure caused by tropospheric disturbance 査読有り Open Access

Akiya, Y; Saito, A; Sakanoi, T; Hozumi, Y; Yamazaki, A; Otsuka, Y; Nishioka, M; Tsugawa, T

GEOPHYSICAL RESEARCH LETTERS 41 巻 ( 19 ) 頁： 6943 - 6948 2014年10月

Auroral fragmentation into patches 査読有り

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

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 119 巻 ( 10 ) 頁： 8249 - 8261 2014年10月

Diagnostics of equatorial and low latitude ionosphere by TEC mapping over Brazil 査読有り

Takahashi, H; Costa, S; Otsuka, Y; Shiokawa, K; Monico, JFG; Paula, E; Nogueira, P; Denardini, CM; Becker-Guedes, F; Wrasse, CM; Ivo, AS; Gomes, VCF; Gargarela, W; Sant'Anna, N; Gatto, R

ADVANCES IN SPACE RESEARCH 54 巻 ( 3 ) 頁： 385 - 394 2014年8月

Observations of GPS scintillation during an isolated auroral substorm 査読有り

Hosokawa, K, Y. Otsuka, Y. Ogawa, T. Tsugawa

Progress in Earth and Planetary Sciencs 96693290710.1186/2197-4284-1-1 巻 2014年8月

Vertical ExB drifts from radar and C/NOFS observations in the Indian and Indonesian sectors: Consistency of observations and model 査読有り Open Access

A. K. Patra, P. Pavan Chaitanya, Y. Otsuka, T. Yokoyama, M. Yamamoto, R. A. Stoneback, R. A. Heelis

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 119 巻 ( 5 ) 頁： 3777 - 3788 2014年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER GEOPHYSICAL UNION

In this paper, we analyze vertical ExB drifts obtained from the Doppler shifts of the daytime 150km radar echoes from two radar stations located off the magnetic equator, namely, Gadanki in India and Kototabang in Indonesia, and compare those with corresponding Coupled Ion Neutral Dynamics Investigation (CINDI) observations onboard the C/NOFS satellite and the Scherliess-Fejer model in an effort to understand to what extent the low-latitude vertical ExB drifts of the 150km region represent the F region vertical ExB drifts. The radar observations were made during 9-16 LT in January, June, July, and December 2009. A detailed comparison reveals that vertical ExB drifts observed by the radars at both locations agree well with those of CINDI and differ remarkably from those of the model. Importantly, the model and observed drifts show large disagreement when the observed drifts are either large or downward. Further, while the CINDI as well as the radar observations from the two longitudes are found to agree with each other on the average, they differ remarkably on several occasions when compared on a one-to-one basis. The observed difference in detail is due to measurements made in different volumes linked with latitudinal and/or longitudinal differences and underlines the role of neutral dynamics linked with tides and gravity waves in the two longitude sectors on the respective vertical ExB drifts. The results presented here are the first of their kind and are expected to have wider applications in furthering our understanding on fine-scale longitudinal variabilities in the ionosphere in general and ionospheric electrodynamics in the Indian and Indonesian sectors in particular.

DOI： 10.1002/2013JA019732

Web of Science

Global imaging of polar cap patches with dual airglow imagers 査読有り Open Access

Hosokawa, K; Taguchi, S; Shiokawa, K; Otsuka, Y; Ogawa, Y; Nicolls, M

GEOPHYSICAL RESEARCH LETTERS 41 巻 ( 1 ) 頁： 1 - 6 2014年1月

赤道大気レーダーを用いた高度150km沿磁力線不規則構造のドリフト速度に関する研究査読有り Open Access

大塚雄一, 水谷徳仁, 塩川和夫, Amit Patra, 横山竜宏, 山本衛

南極資料頁：印刷中 2014年

The observation of equatorial plasma bubble using all sky imager and GPS TEC measurement 査読有り

Suhaila M. Buhari, Mardina Abdullah, Alina Marie Hasbi, Yuichi Otsuka, Siti Aminah Bahari, Mohd Hezri Mokhtar, Michi Nishioka, Takuya Tsugawa

2014 XXXITH URSI GENERAL ASSEMBLY AND SCIENTIFIC SYMPOSIUM (URSI GASS) 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

In this study, the two-dimensional horizontal structure of EPB was observed using GPS total electron content (TEC) measurement in South East Asia region. Rate of TEC index (ROTI) is calculated from GPS TEC measurement and plotted onto two-dimensional map in geographic coordinate. Depletion of The OI 630.0 nm emission is completely coincided with ROTI enhancement region from GPS TEC measurement. Therefore, the observation using GPS TEC measurement is able to provide spatial and temporal properties of EPB in SEA region.

Web of Science

Vertical ExB drifts from radar and C/NOFS observations in the Indian and Indonesian sectors: Consistency of observations and model 査読有り Open Access

A. K. Patra, P. Pavan Chaitanya, Y. Otsuka, T. Yokoyama, M. Yamamoto, R. A. Stoneback, R. A. Heelis

Journal of Geophysical Research: Space Physics 119 巻 ( 5 ) 頁： 3777 - 3788 2014年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Blackwell Publishing Ltd

In this paper, we analyze vertical ExB drifts obtained from the Doppler shifts of the daytime 150 km radar echoes from two radar stations located off the magnetic equator, namely, Gadanki in India and Kototabang in Indonesia, and compare those with corresponding Coupled Ion Neutral Dynamics Investigation (CINDI) observations onboard the C/NOFS satellite and the Scherliess-Fejer model in an effort to understand to what extent the low-latitude vertical ExB drifts of the 150 km region represent the F region vertical ExB drifts. The radar observations were made during 9-16 LT in January, June, July, and December 2009. A detailed comparison reveals that vertical ExB drifts observed by the radars at both locations agree well with those of CINDI and differ remarkably from those of the model. Importantly, the model and observed drifts show large disagreement when the observed drifts are either large or downward. Further, while the CINDI as well as the radar observations from the two longitudes are found to agree with each other on the average, they differ remarkably on several occasions when compared on a one-to-one basis. The observed difference in detail is due to measurements made in different volumes linked with latitudinal and/or longitudinal differences and underlines the role of neutral dynamics linked with tides and gravity waves in the two longitude sectors on the respective vertical ExB drifts. The results presented here are the first of their kind and are expected to have wider applications in furthering our understanding on fine-scale longitudinal variabilities in the ionosphere in general and ionospheric electrodynamics in the Indian and Indonesian sectors in particular. Key Points First comparison of 150 km echo and C/NOFS ExB drifts over India and Indonesia These observations agree at both locations and show some longitudinal difference Radar and C/NOFS observations differ remarkably from model ©2014. American Geophysical Union. All Rights Reserved.

DOI： 10.1002/2013JA019732

Scopus

Two-dimensional structure of equatorial plasma bubble observed using GPS networks in South East Asia region 査読有り

Suhaila M. Buhari, Mardina Abdullah, Alina Marie Hasbi, Yuichi Otsuka

2014 International Conference on Electronics, Information and Communications (ICEIC) 2014年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

Malaysia is located at equatorial region, which is from 3 degrees to 8 degrees South of the magnetic equator where equatorial plasma bubbles (EPBs) frequently occur. EPBs could disrupt radio communication and navigational systems in this region. We present the two-dimensional structure of EPBs observed using GPS networks over South East Asia (SEA) near the equatorial region. 59 days with EPB structure were observed using GPS networks in 2011. The results show that; 1) the initial EPBs onset time occurs mostly after post-sunset between 1900 to 2100 local time (LT); 2) the duration of the occurrences of EPB is mostly from 3 to 6 hours; 3) the GPS networks in SEA region are able to observe east-west size of EPBs from 50 km to 650 km with accuracy +/-50 km.

Web of Science

国際宇宙ステーションからの大気光観測による赤道域電離圏擾乱の研究

山田貴宣, 大塚雄一, 坂野井健, 山崎敦, 齊藤昭則, 秋谷祐亮

第28回大気圏シンポジウム講演集 2014年

国際宇宙ステーションからの超高層大気撮像観測ミッションISS-IMAPの現状

齊藤昭則, 秋谷祐亮, 穂積裕太, 山崎敦, 阿部琢美, 鈴木睦, 村上豪, 坂野井健, 吉川一朗, 大塚雄一, 藤原均, 田口真, 山本衛, 中村卓司, 江尻省, 菊池雅行, 河野英昭, Huixin Liu, 石井守, 久保田実, 津川卓也, 星野尾一明, 坂野井和代, IMAPワーキンググループ

第14回宇宙科学シンポジウム講演集 2014年

赤道大気レーダーを用いた高度150km沿磁力線不規則構造のドリフト速度に関する研究査読有り Open Access

大塚雄一, 水谷徳仁, 塩川和夫, Amit Patra, 横山竜宏, 山本衛

南極資料 57 巻 ( 3 ) 頁： 369-378 2013年11月

Typhoon-induced concentric airglow structures in the mesopause region 査読有り

S. Suzuki, S. L. Vadas, K. Shiokawa, Y. Otsuka, S. Kawamura, Y. Murayama

Geophysical Research Letters 40 巻 ( 22 ) 頁： 5983 - 5987 2013年11月

記述言語：英語掲載種別：研究論文（学術雑誌）

We present the first reported gravity wave patterns in the mesopause region caused by a typhoon in the troposphere. On 10 December 2002, concentric rings of gravity waves in OH airglow were observed simultaneously by all-sky imagers in the Optical Mesosphere and Thermosphere Imager system in Japan, located at Rikubetsu (43.5°N, 143.8°E), Shigaraki (34.9°N, 136.1°E), and Sata (31.0°N, 130.7°E). The airglow structures, which were well defined and formed a coherent wave pattern expanding concentrically, were identified over 8 h (2135-2947 LT). We estimate the horizontal wavelength, horizontal phase speed, and wave period as 34.5 km, 50.2 m s-1, and 11.5 min, respectively. Infrared cloud images from the Geostationary Meteorological Satellite show that the center of the rings estimated from the airglow data corresponds to a spiral band of Typhoon Pongsona (T0226). This unique event provides new insight into coupling between the lower and upper atmosphere. ©2013. American Geophysical Union. All Rights Reserved.

DOI： 10.1002/2013GL058087

Scopus

Typhoon-induced concentric airglow structures in the mesopause region 査読有り

S. Suzuki, S. L. Vadas, K. Shiokawa, Y. Otsuka, S. Kawamura, Y. Murayama

GEOPHYSICAL RESEARCH LETTERS 40 巻 ( 22 ) 頁： 5983 - 5987 2013年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER GEOPHYSICAL UNION

We present the first reported gravity wave patterns in the mesopause region caused by a typhoon in the troposphere. On 10 December 2002, concentric rings of gravity waves in OH airglow were observed simultaneously by all-sky imagers in the Optical Mesosphere and Thermosphere Imager system in Japan, located at Rikubetsu (43.5 degrees N, 143.8 degrees E), Shigaraki (34.9 degrees N, 136.1 degrees E), and Sata (31.0 degrees N, 130.7 degrees E). The airglow structures, which were well defined and formed a coherent wave pattern expanding concentrically, were identified over 8 h (2135-2947 LT). We estimate the horizontal wavelength, horizontal phase speed, and wave period as 34.5 km, 50.2 m s(-1), and 11.5 min, respectively. Infrared cloud images from the Geostationary Meteorological Satellite show that the center of the rings estimated from the airglow data corresponds to a spiral band of Typhoon Pongsona (T0226). This unique event provides new insight into coupling between the lower and upper atmosphere.

DOI： 10.1002/2013GL058087

Web of Science

Two-dimensional simulation of ionospheric variations in the vicinity of the epicenter of the Tohoku-oki earthquake on 11 March 2011 査読有り

Shinagawa, H; Tsugawa, T; Matsumura, M; Iyemori, T; Saito, A; Maruyama, T; Jin, H; Nishioka, M; Otsuka, Y

GEOPHYSICAL RESEARCH LETTERS 40 巻 ( 19 ) 頁： 5009 - 5013 2013年10月

Longitudinal characteristics of spread F backscatter plumes observed with the EAR and Sanya VHF radar in Southeast Asia 査読有り Open Access

Guozhu Li, Baiqi Ning, M. A. Abdu, Yuchi Otsuka, T. Yokoyama, M. Yamamoto, Libo Liu

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 118 巻 ( 10 ) 頁： 6544 - 6557 2013年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER GEOPHYSICAL UNION

The development of equatorial plasma irregularity plumes can be well recorded by steerable backscatter radars operated at and off the magnetic equator due to the fact that the vertically extended plume structures are tracers of magnetically north-south aligned larger scale structures. From observations during March 2012, using two low latitude steerable backscatter radars in Southeast Asia, the Equatorial Atmosphere Radar (EAR) (0.2 degrees S, 100.3 degrees E; dip lat 10.4 degrees S) and the Sanya VHF radar (18.4 degrees N, 109.6 degrees E; dip lat 12.8 degrees N), the characteristics of backscatter plumes over the two sites separated in longitude by similar to 1000 km were simultaneously investigated. The beam steering measurements reveal frequent occurrences of multiple plumes over both radar sites, of which two cases are analyzed here. The observations on 30 March 2012 show plume structures initiated within the radar scanned area, followed by others drifting from the west of the radar beam over both stations. A tracing analysis on the onset locations of plasma plumes reveals spatially well-separated backscatter plumes, with a maximum east-west wavelength of about 1000 km, periodically generated in longitudes between 85 degrees E and 110 degrees E. The postsunset backscatter plumes seen by the Sanya VHF radar are found to be due to the passage of sunset plumes initiated around the longitude of EAR. Most interestingly, the EAR measurements on the night of 21 March 2012 show multiple plume structures that developed successively in the radar scanned area with east-west separation of similar to 50 km, with however no sunset plasma plume over Sanya. Colocated ionogram measurements show that spread F irregularities occurred mainly in the bottomside F region at Sanya, whereas satellite traces in ionograms that are indications of large-scale wave structures were observed on that night at both stations. Possible causes for the longitudinal difference in the characteristics of radar backscatter plumes are discussed.

DOI： 10.1002/jgra.50581

Web of Science

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

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

JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS 103 巻頁： 184 - 194 2013年10月

Ionogram-based range-time displays for observing relationships between ionosonde satellite traces, spread F and drifting optical plasma depletions 査読有り

Lynn, KJW; Otsuka, Y; Shiokawa, K

JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS 98 巻頁： 105 - 112 2013年6月

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