Faculty Profiles - OTSUKA, Yuichi

Papers - OTSUKA, Yuichi

Division display 41 - 60 of about 496 ／ All the affair displays >>

Three-Dimensional Fourier Analysis of Atmospheric Gravity Waves and Medium-Scale Traveling Ionospheric Disturbances Observed in Airglow Images in Hawaii Over Three Years

Naito Hideto, Shiokawa Kazuo, Otsuka Yuichi, Fujinami Hatsuki, Tsuboi Takuma, Sakanoi Takeshi, Saito Akinori, Nakamura Takuji

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 127 ( 10 ) 2022.10

Statistical Study of Subauroral Arc Detachment at Athabasca, Canada: New Insights on STEVE

Yadav, S; Shiokawa, K; Otsuka, Y; Connors, M

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 127 ( 9 ) 2022.9

Electromagnetic conjugacy of ionospheric disturbances after the 2022 Hunga Tonga-Hunga Ha'apai volcanic eruption as seen in GNSS-TEC and SuperDARN Hokkaido pair of radars observations Open Access

Shinbori Atsuki, Otsuka Yuichi, Sori Takuya, Nishioka Michi, Perwitasari Septi, Tsuda Takuo, Nishitani Nozomu

EARTH PLANETS AND SPACE Vol. 74 ( 1 ) 2022.7

Modeling Post-Sunset Equatorial Spread-F Occurrence as a Function of Evening Upward Plasma Drift Using Logistic Regression, Deduced from Ionosondes in Southeast Asia Open Access

Abadi, P; Ahmad, UA; Otsuka, Y; Jamjareegulgarn, P; Martiningrum, DR; Faturahman, A; Perwitasari, S; Saputra, RE; Septiawan, RR

REMOTE SENSING Vol. 14 ( 8 ) 2022.4

Variations of Zonal Wind Velocity in the Thermosphere Observed at Southeast Asian Sector During Quiet and Active Geomagnetic Days

Sarudin, I; Hamid, NSA; Abdullah, M; Rusli, FNSM; Otsuka, Y; Shiokawa, K; Yatini, C; Komonjinda, S; Somboon, E

JURNAL FIZIK MALAYSIA Vol. 43 ( 1 ) page： 10025 - 10035 2022

Xtend, the Soft X-ray Imaging Telescope for the X-ray Imaging and Spectroscopy Mission (XRISM) Open Access

Mori, K; Tomida, H; Nakajima, H; Okajima, T; Noda, H; Tanaka, T; Uchida, H; Hagino, K; Kobayashi, SB; Suzuki, H; Yoshida, T; Murakami, H; Uchiyama, H; Nobukawa, M; Nobukawa, KK; Yoneyama, T; Matsumoto, H; Tsuru, TG; Yamauchi, M; Hatsukade, I; Ishida, M; Maeda, Y; Hayashi, T; Tamura, K; Boissay-Malaquin, R; Sato, T; Hiraga, J; Kohmura, T; Yamaoka, K; Dotani, T; Ozaki, M; Tsunemi, H; Kanemaru, Y; Sato, J; Takaki, T; Terada, Y; Miyazaki, K; Kusunoki, K; Otsuka, Y; Yokosu, H; Yonemaru, W; Asahina, Y; Asakura, K; Yoshimoto, M; Ode, Y; Sato, J; Hakamata, T; Aoyagi, M; Aoki, Y; Tsunomachi, S; Doi, T; Aoki, D; Fujisawa, K; Kitajima, M; Hayashida, K

SPACE TELESCOPES AND INSTRUMENTATION 2022: ULTRAVIOLET TO GAMMA RAY Vol. 12181 2022

ROLES OF EVENING EASTWARD NEUTRAL WIND AND EQUATORIAL ELECTROJET ON PRE-REVERSAL ENHANCEMENT INFERRED FROM GOCE SATELLITE AND GROUND-BASED OBSERVATIONS Open Access

Abadi, P; Otsuka, Y; Liu, HX; Hozumi, K; Martiningrum, DR

18TH ANNUAL MEETING OF THE ASIA OCEANIA GEOSCIENCES SOCIETY, AOGS 2021 page： 218 - 220 2022

An experimental investigation into the possible connections between the zonal neutral wind speeds and equatorial plasma bubble drift velocities over the African equatorial region Open Access

Okoh, DI; Rabiu, AB; Shiokawa, K; Otsuka, Y; Wu, Q; Seemala, GK; Katamzi-Joseph, ZT

JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS Vol. 220 2021.9

Preface to the Special Issue on recent advances in the study of Equatorial Plasma Bubbles and Ionospheric Scintillation Open Access

Otsuka, Y; Spogli, L; Ram, ST; Li, GZ

EARTH AND PLANETARY PHYSICS Vol. 5 ( 5 ) page： 365 - 367 2021.9

L-Band Synthetic Aperture Radar Observation of Ionospheric Density Irregularities at Equatorial Plasma Depletion Region Open Access

Sato, H; Kim, JS; Otsuka, Y; Wrasse, CM; de Paula, ER; de Souza, JR

GEOPHYSICAL RESEARCH LETTERS Vol. 48 ( 16 ) 2021.8

Characteristics of Medium-Scale Traveling Ionospheric Disturbances and Ionospheric Irregularities at Mid-Latitudes Revealed by the Total Electron Content Associated With the Beidou Geostationary Satellite

Huang, F; Lei, J; Otsuka, Y; Luan, X; Liu, Y; Zhong, J; Dou, X

IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Vol. 59 ( 8 ) page： 6424 - 6430 2021.8

Statistical study of medium-scale traveling ionospheric disturbances in low-latitude ionosphere using an automatic algorithm Open Access

Cheng, PH; Lin, C; Otsuka, Y; Liu, HL; Rajesh, PK; Chen, CH; Lin, JT; Chang, MT

EARTH PLANETS AND SPACE Vol. 73 ( 1 ) 2021.5

Medium-Scale Traveling Ionospheric Disturbances

Otsuka, Y

IONOSPHERE DYNAMICS AND APPLICATIONS Vol. 260 page： 421 - 437 2021

Equatorial Plasma Bubble Occurrence Under Propagation of MSTID and MLT Gravity Waves Open Access

Takahashi, H; Wrasse, CM; Figueiredo, CAOB; Barros, D; Paulino, I; Essien, P; Abdu, MA; Otsuka, Y; Shiokawa, K

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 125 ( 9 ) 2020.9

Temporal and Spatial Variations of Total Electron Content Enhancements During a Geomagnetic Storm on 27 and 28 September 2017 Open Access

Shinbori, A; Otsuka, Y; Sori, T; Tsugawa, T; Nishioka, M

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 125 ( 7 ) 2020.7

Equatorial Plasma Bubble Zonal Drift Velocity Variations in Response to Season, Local Time, and Solar Activity across Southeast Asia

Sarudin, I; Hamid, NSA; Abdullah, M; Buhari, SM; Shiokawa, K; Otsuka, Y; Yatini, CY

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 125 ( 3 ) 2020.3

Multievent Analysis of Oscillatory Motion of Medium-Scale Traveling Ionospheric Disturbances Observed by a 630-nm Airglow Imager Over Tromso Open Access

Yadav, S; Shiokawa, K; Oyama, S; Otsuka, Y

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 125 ( 3 ) 2020.3

Wavenumber Spectra of Atmospheric Gravity Waves and Medium-Scale Traveling Ionospheric Disturbances Based on More Than 10-Year Airglow Images in Japan, Russia, and Canada Open Access

Satoshi Tsuchiya, Kazuo Shiokawa, Yuichi Otsuka, Takuji Nakamura, Mamoru Yamamoto, Martin Connors, Ian Schofield, Boris Shevtsov, Igor Poddelsky

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 125 ( 3 ) 2020.3

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER GEOPHYSICAL UNION

We have studied atmospheric gravity waves (AGWs) and nighttime medium-scale traveling ionospheric disturbances (MSTIDs) by applying three-dimensional spectral analysis technique to 557.7- and 630.0-nm airglow images at Shigaraki (SGK) (35 degrees N, 136 degrees E, 1999-2017) and Rikubetsu (RIK) (44 degrees N, 144 degrees E, 1999-2017), Japan, Athabasca (ATH), Canada, (55 degrees N, 247 degrees E, 2005-2017), and Magadan (MGD), Russia (60 degrees N, 151 degrees E, 2008-2017), focusing on their horizontal wavenumber spectra. For the AGWs in 557.7-nm images, the power spectra in summer are stronger than in other seasons, probably due to stronger tropospheric convection. The highest energy content of the waves are mostly at wavelengths between 20 and 300 km at MGD, ATH, and RIK, while it is above 200 km at SGK. The largest power spectral density is obtained at RIK at wavelengths of 30-100 km and then ATH. The slopes of the horizontal wavenumber spectra varies from -2.77 to -3.22. From the MSTIDs in 630.0-nm images, the power spectra in summer at RIK and SGK are stronger than those in other seasons regardless of solar activity. The power spectra in solar quiet time are stronger than those in solar active time at all four stations. These features can be explained by the Perkins instability with coupling between sporadic E and F layers. The spectral slope decreases with increasing latitudes. Weak positive correlations were obtained between the daily wave power of AGWs in 557.7-nm images and MSTIDs in 630.0-nm images, suggesting that the MSTIDs in the thermosphere may be partially generated by the AGWs from the mesopause region.Plain Language Summary In this paper we study atmospheric gravity waves (AGWs) and nighttime medium-scale traveling ionospheric disturbances (MSTIDs) observed at four stations in Japan, Canada, and Russia, in 557.7- and 630.0-nm airglow images over more than 10 years. The 557.7-nm airglow has an emission layer at altitudes of 90-100 km (mesopause region). The waves seen in the 557.7-nm airglow images mainly indicates AGWs. The 630.0-nm airglow has an emission layer at altitudes of 200-300 km (bottomside ionosphere). The waves seen in the 630.0-nm airglow images mainly indicates MSTIDs in the ionosphere. The AGWs in the mesopause region are the main driver of global atmospheric circulation in the middle atmosphere. The MSTIDs in the bottomside ionosphere are one of the causes of the satellite positioning error. We show typical energy content, propagation direction, and wavelengths of these waves at these two altitudes and discuss possible reason of the observed characteristics. These results contribute to our understanding of generation and propagation of AGWs and MSTIDs in the upper atmosphere.

DOI： 10.1029/2019JA026807

Open Access

Web of Science

Characteristics of GNSS Total Electron Content Enhancements Over the Midlatitudes During a Geomagnetic Storm on 7 and 8 November 2004 Open Access

Sori, T; Shinbori, A; Otsuka, Y; Tsugawa, T; Nishioka, M

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 124 ( 12 ) page： 10376 - 10394 2019.12

Adjuvant therapy with nivolumab versus ipilimumab after complete resection of stage III/IV melanoma: Japanese subgroup analysis from the phase 3 CheckMate 238 study Open Access

Yokota, K; Uchi, H; Uhara, H; Yoshikawa, S; Takenouchi, T; Inozume, T; Ozawa, K; Ihn, H; Fujisawa, Y; Qureshi, A; de Pril, V; Otsuka, Y; Weber, J; Yamazaki, N

JOURNAL OF DERMATOLOGY Vol. 46 ( 12 ) page： 1197 - 1201 2019.12

　 PREV - NEXT 　

<OTSUKA, Yuichi>

Papers - OTSUKA, Yuichi