研究者詳細 - 大塚　雄一

論文 - 大塚　雄一

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Response of nighttime equatorial and low latitude F-region to the geomagnetic storm of August 18, 2003, in the Brazilian sector 査読有り

Sahai, Y; Becker-Guedes, F; Fagundes, PR; Lima, WLC; Otsuka, Y; Huang, CS; Espinoza, ES; Pi, X; de Abreu, AJ; Bolzan, MJA; Pillat, VG; Abalde, JR; Pimenta, AA; Bittencourt, JA

ADVANCES IN SPACE RESEARCH 39 巻 ( 8 ) 頁： 1325 - 1334 2007年

Development of airglow temperature photometers with cooled-CCD detectors 査読有り

Shiokawa, K; Otsuka, Y; Suzuki, S; Katoh, T; Katohl, Y; Satoh, M; Ogawa, T; Takahashi, H; Gobbli, D; Nakamura, T; Williams, BP; She, CY; Taguchi, M; Shimomai, T

EARTH PLANETS AND SPACE 59 巻 ( 6 ) 頁： 585 - 599 2007年

Gravity wave momentum flux in the upper mesosphere derived from OH airglow imaging measurements 査読有り

Suzuki, S; Shiokawa, K; Otsuka, Y; Ogawa, T; Kubota, M; Tsutsumi, M; Nakamura, T; Fritts, DC

EARTH PLANETS AND SPACE 59 巻 ( 5 ) 頁： 421 - 428 2007年

Summer-winter hemispheric asymmetry of sudden increase in ionospheric total electron content induced by solar flares: A role of O/N-2 ratio 査読有り

Tsugawa T., Sadakane T., Sato J., Otsuka Y., Ogawa T., Shiokawa K., Saito A.

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 111 巻 ( A11 ) 2006年11月

A fast-propagating, large-scale atmospheric gravity wave observed in the WAVE2004 campaign 査読有り

Kubota, M; Kawamura, S; Abo, M; Koizumi, Y; Murayama, Y; Yamamori, M; Shiokawa, K; Otsuka, Y; Uchiumi, M; Igarashi, K; Abe, T; Oyama, KI; Iwagami, N

JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 111 巻 ( D21 ) 2006年11月

Detection of ruptures of Andaman fault segments in the 2004 great Sumatra earthquake with coseismic ionospheric disturbances 査読有り

Heki, K; Otsuka, Y; Choosakul, N; Hemmakorn, N; Komolmis, T; Maruyama, T

JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 111 巻 ( B9 ) 2006年9月

Estimating drift velocity of polar cap patches with all-sky airglow imager at Resolute Bay, Canada 査読有り

Hosokawa, K; Shiokawa, K; Otsuka, Y; Nakajima, A; Ogawa, T; Kelly, JD

GEOPHYSICAL RESEARCH LETTERS 33 巻 ( 15 ) 2006年8月

A multi-instrument measurement of a mesospheric front-like structure at the equator 査読有り

Shiokawa, K; Suzuki, S; Otsuka, Y; Ogawa, T; Nakamura, T; Mlynczak, MG; Russell, JM

JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN 84A 巻頁： 305 - 316 2006年7月

Equatorial ionospheric scintillations and zonal irregularity drifts observed with closely-spaced GPS receivers in Indonesia 査読有り

Otsuka, Y; Shiokawa, K; Ogawa, T

JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN 84A 巻頁： 343 - 351 2006年7月

Ionospheric disturbances over Indonesia and their possible association with atmospheric gravity waves from the troposphere 査読有り

Ogawa, T; Otsuka, Y; Shiokawa, K; Saito, A; Nishioka, M

JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN 84A 巻頁： 327 - 342 2006年7月

Quasiperiodic southward moving waves in 630-nm airglow images in the equatorial thermosphere 査読有り

Shiokawa, K; Otsuka, Y; Ogawa, T

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 111 巻 ( A6 ) 2006年6月

Characteristics and implications of Doppler spectra of E region quasi-periodic echoes observed by the multibeam middle and upper atmosphere radar 査読有り

Ogawa Tadahiko, Otsuka Yuichi, Yamamoto Mamoru

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 111 巻 ( A5 ) 2006年5月

Climatological study of GPS total electron content variations caused by medium-scale traveling ionospheric disturbances 査読有り

Kotake, N; Otsuka, Y; Tsugawa, T; Ogawa, T; Saito, A

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 111 巻 ( A4 ) 2006年4月

Geomagnetic conjugate observations of large-scale traveling ionospheric disturbances using GPS networks in Japan and Australia 査読有り

Tsugawa, T; Shiokawa, K; Otsuka, Y; Ogawa, T; Saito, A; Nishioka, M

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 111 巻 ( A2 ) 2006年2月

Equatorial ionospheric scintillations and zonal irregularity drifts observed with closely-spaced GPS receivers in Indonesia 査読有り

Otsuka, Y., K. Shiokawa, and T. Ogawa

J. Meteor. Soc. Japan 84A 巻頁： 343-351 2006年

GPS detection of total electron content variations over Indonesia and Thailand following the 26 December 2004 earthquake 査読有り

Otsuka, Y., N. Kotake, T. Tsugawa, K. Shiokawa, T. Ogawa, Effendy, S. Saito, M. Kawamura, T. Maruyama, N. Hemmakorn, and T. Komolmis

Earth, Planets and Space 58 巻頁： 159-165 2006年

A statistical study of ionospheric irregularities observed with a GPS network in Japan

Otsuka, Y; Aramaki, T; Ogawa, T; Saito, A

RECURRENT MAGNETIC STORMS: COROTATING SOLAR WIND STREAMS 167 巻頁： 271 - + 2006年

© 2006 by the American Geophysical Union. All rights reserved. The Geographical Survey Institute of Japan has installed a network of about 1000 dual-frequency GPS receivers in Japan with their mutual distance of about 25 km. Phases and pseudo ranges of dual-frequency GPS signals are recorded every 30 s. The dense distribution of the GPS receivers allows us to reveal twodimensional structures of the ionospheric plasma density irregularities with scale sizes of the order of several kilometers. We analyzed TEC data obtained from the GPS network of Japan in 2000. It was found that the irregularity characteristics over Japan depended on latitude. The results are as follows: (1) at the northern part, the irregularities appeared only during geomagnetic storms. (2) At the middle part, they had the most frequent occurrence in summer nighttime and were usually accompanied by Medium-Scale Traveling Ionospheric Disturbances (MSTID). (3) At the southern part, they were associated with the equatorial plasma bubbles and their occurrences were highest in the equinoctial nighttime.

DOI： 10.1029/167GM21

Web of Science

Scopus

GPS observations of post-storm TEC enhancements at low latitudes 査読有り

Kutiev, I; Otsuka, Y; Saito, A; Watanabe, S

EARTH PLANETS AND SPACE 58 巻 ( 11 ) 頁： 1479 - 1486 2006年

GPS detection of total electron content variations over Indonesia and Thailand following the 26 December 2004 earthquake 査読有り

Otsuka, Y; Kotake, N; Tsugawa, T; Shiokawa, K; Ogawa, T; Effendy; Saito, S; Kawamura, M; Maruyama, T; Hemmakorn, N; Komolmis, T

EARTH PLANETS AND SPACE 58 巻 ( 2 ) 頁： 159 - 165 2006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：The Seismological Society of Japan, Society of Geomagnetism and Earth, Planetary and Space Sciences, The Volcanological Society of Japan , The Geodetic Society of Japan , The Japanese Society for Planetary Sciences

We report the response of the ionosphere to the large earthquake that occurred in West Sumatra, Indonesia, at 0058 UT on December 26, 2004. We have analyzed Global Positioning System (GPS) data obtained at two sites in Sumatra and at three sites in Thailand to investigate total electron content (TEC) variations. Between 14 and 40 min after the earthquake, TEC enhancements of 1.6-6.9 TEC units (TECU) were observed at subionospheric points located 360-2000 km north of the epicenter. From the time delays of the observed TEC enhancements, we find that the TEC enhancements propagated northward from the epicenter. The time delays between the earthquake and rapid increases in TEC, which occurred near the epicenter, are consistent with the idea that acoustic waves generated by the earthquake propagated into the ionosphere at the speed of sound to cause the TEC variations. A small TEC enhancement of 0.6 TECU was observed south of the epicenter, while no TEC enhancements were seen east of the epicenter. From a model calculation, we find that this directivity of the TEC variations with respect to the azimuth from the epicenter could be caused partially by the directivity in the response of the electron density variation to the acoustic waves in the neutral atmosphere. © 2006, The Seismological Society of Japan, Society of Geomagnetism and Earth, Planetary and Space Sciences, The Volcanological Society of Japan, The Geodetic Society of Japan, The Japanese Society for Planetary Sciences. All rights reserved.

DOI： 10.1186/BF03353373

Web of Science

Scopus

Ionospheric variations at midlatitude detected by a dense GPS receiver array in Japan 査読有り

A. Saito, Y. Otsuka, T. Tsugawa, K. Matsunaga, K. Hoshinoo

Proceedings of the Annual Meeting - Institute of Navigation 頁： 425 - 428 2005年12月

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）

Ionospheric variations over Japan were investigated with high spatial and temporal resolution data of GEONET, which consists of about 1,200 GPS receivers. Total Electron Content (TEC) data derived from GEONET clarified that various ionospheric phenomena cause the variation of the ionosphere in the region around 30 degrees of the geomagnetic latitude, and affect on the navigation system. The large day-to-day variation of TEC gradient over Japan was found to be attributed to the day-to-day variation of the Equatorial Ionization Anomaly (EIA) because Japan is located on the northern slope of EIA. The amplitude and location of EIA have large variability because they are controlled by a complex system among the neutral and the ionized atmospheres, lower and upper atmospheres, and low-latitude and high-latitude ionospheres. As a result, the variation of EIA is difficult to be predicted. Meso-scale ionospheric structures, such as medium-scale traveling ionospheric disturbances (MSTID) and plasma bubbles, drift in about 100m/s of velocity and cause variations of short temporal scale. They were often observed to be accompanied by smaller scale structures that generate phase and amplitude scintillations of the GPS radio waves. The activity of MSTID has maxima in summer and winter. During these maximum periods, they were detected by GEONET almost everyday. Plasma bubbles were detected in the lowest latitude area of Japan, and found to reach the central part of Japan in a few days in a year. Most of them were in the geomagnetically disturbed periods. The geomagnetic disturbances also generate large-scale traveling ionospheric disturbances and reduction of TEC.

Scopus

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