研究者詳細 - 野澤　悟徳

論文 - 野澤　悟徳

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A statistical study of convective and dynamic instabilities in the polar upper mesosphere above Tromso 査読有り国際共著国際誌

Nozawa, S; Saito, N; Kawahara, T; Wada, S; Tsuda, TT; Maeda, S; Takahashi, T; Fujiwara, H; Narayanan, VL; Kawabata, T; Johnsen, MG

EARTH PLANETS AND SPACE 75 巻 ( 1 ) 2023年2月

A new five-wavelength photometer operated in TromsO (69.6°N, 19.2°E)

Nozawa, S; Kawabata, T; Hosokawa, K; Ogawa, Y; Tsuda, T; Mizuno, A; Fujii, R; Hall, C

EARTH PLANETS AND SPACE 70 巻 2018年12月

Atmospheric Gravity Waves and Medium Scale Traveling Ionospheric Disturbances at Auroral Latitudes

Kozlovsky, A; Stober, G; Sherstyukov, R; Lester, M; Belova, E; Kero, J; Tsutsumi, M; Gulbrandsen, N; Nozawa, S

SURVEYS IN GEOPHYSICS 2025年3月

D-Region Ion-Neutral Collision Frequency Observed by Incoherent Scatter Spectral Width Combined With LIDAR Measurements

Thomas, N; Kero, A; Virtanen, I; Nozawa, S; Saito, N

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 130 巻 ( 3 ) 2025年3月

Heavy Molecular and Metallic Ions in the Magnetosphere

Yamauchi, M; Christon, S; Dandouras, I; Haaland, S; Kastinen, D; Kistler, LM; Mann, I; Nozawa, S; Plane, JMC; Saito, Y; Schulz, L; Watababe, S; Wurz, P; Yau, AW

SPACE SCIENCE REVIEWS 220 巻 ( 8 ) 2024年12月

Occurrence of Mesospheric Frontal Structures Over the High Latitude Station, Tromsø, Norway

Chauhan, N; Shiokawa, K; Gurubaran, S; Nozawa, S; Oyama, SI; Nakamura, T

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 129 巻 ( 7 ) 2024年7月

Dissipation Rates of Mesospheric Stratified Turbulence From Multistatic Meteor-Radar Observations

Vierinen, J; Poblet, FL; Chau, JL; Avsarkisov, V; Pécseli, HL; Tsutsumi, M; Nozawa, S; Johnsen, MG; Latteck, R; Gulbrandsen, N

GEOPHYSICAL RESEARCH LETTERS 51 巻 ( 11 ) 2024年6月

Influence of meteoric smoke particles on the incoherent scatter measured with EISCAT VHF

Gunnarsdottir, TL; Mann, I; Feng, WH; Huyghebaert, DR; Haeggstroem, I; Ogawa, Y; Saito, N; Nozawa, S; Kawahara, TD

ANNALES GEOPHYSICAE 42 巻 ( 1 ) 頁： 213 - 228 2024年6月

Gravity waves generated by the Hunga Tonga-Hunga Ha′apai volcanic eruption and their global propagation in the mesosphere/lower thermosphere observed by meteor radars and modeled with the High-Altitude general Mechanistic Circulation Model

Stober, G; Vadas, SL; Becker, E; Liu, AL; Kozlovsky, A; Janches, D; Qiao, ZS; Krochin, W; Shi, GC; Yi, W; Zeng, J; Brown, P; Vida, D; Hindley, N; Jacobi, C; Murphy, D; Buriti, R; Andrioli, V; Batista, P; Marino, J; Palo, S; Thorsen, D; Tsutsumi, M; Gulbrandsen, N; Nozawa, S; Lester, M; Baumgarten, K; Kero, J; Belova, E; Mitchell, N; Moffat-Griffin, T; Li, N

ATMOSPHERIC CHEMISTRY AND PHYSICS 24 巻 ( 8 ) 頁： 4851 - 4873 2024年4月

Post-midnight purple arc and patches appeared on the high latitude part of the auroral oval: Dawnside counterpart of STEVE?

Nanjo, S; Hofstra, GA; Shiokawa, K; Shinbori, A; Nozawa, S; Hosokawa, K

EARTH PLANETS AND SPACE 76 巻 ( 1 ) 2024年4月

The first simultaneous spectroscopic and monochromatic imaging observations of short-wavelength infrared aurora of N2+ Meinel (0,0) band at 1.1 μm with incoherent scatter radar

Nishiyama, T; Kagitani, M; Furutachi, S; Iwasa, Y; Ogawa, Y; Tsuda, TT; Dalin, P; Tsuchiya, F; Nozawa, S; Sigernes, F

EARTH PLANETS AND SPACE 76 巻 ( 1 ) 2024年2月

Inferring neutral winds in the ionospheric transition region from atmospheric-gravity-wave traveling-ionospheric-disturbance (AGW-TID) observations with the EISCAT VHF radar and the Nordic Meteor Radar Cluster

Günzkofer, F; Pokhotelov, D; Stober, G; Mann, I; Vadas, SL; Becker, E; Tjulin, A; Kozlovsky, A; Tsutsumi, M; Gulbrandsen, N; Nozawa, S; Lester, M; Belova, E; Kero, J; Mitchell, NJ; Borries, C

ANNALES GEOPHYSICAE 41 巻 ( 2 ) 頁： 409 - 428 2023年10月

A Ground-Based Instrument Suite for Integrated High-Time Resolution Measurements of Pulsating Aurora With Arase

Hosokawa, K; Oyama, SI; Ogawa, Y; Miyoshi, Y; Kurita, S; Teramoto, M; Nozawa, S; Kawabata, T; Kawamura, Y; Tanaka, YM; Miyaoka, H; Kataoka, R; Shiokawa, K; Brändström, U; Turunen, E; Raita, T; Johnsen, MG; Hall, C; Hampton, D; Ebihara, Y; Kasahara, Y; Matsuda, S; Shinohara, I; Fujii, R

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 128 巻 ( 8 ) 2023年8月

Interhemispheric Coupling Study by Observations and Modelling (ICSOM): Concept, Campaigns, and Initial Results

Sato, K; Tomikawa, Y; Kohma, M; Yasui, R; Koshin, D; Okui, H; Watanabe, S; Miyazaki, K; Tsutsumi, M; Murphy, D; Meek, C; Tian, YF; Ern, M; Baumgarten, G; Chau, JL; Chu, XZ; Collins, R; Espy, PJ; Hashiguchi, H; Kavanagh, AJ; Latteck, R; Lübken, FJ; Milla, M; Nozawa, S; Ogawa, Y; Shiokawa, K; Alexander, MJ; Nakamura, T; Ward, WE

JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 128 巻 ( 11 ) 2023年6月

History of EISCAT - Part 6: the participation of Japan in the EISCAT Scientific Association

Matuura, N; Fujii, R; Nozawa, S

HISTORY OF GEO- AND SPACE SCIENCES 14 巻 ( 1 ) 頁： 61 - 69 2023年5月

Identifying gravity waves launched by the Hunga Tonga-Hunga Ha'apai volcanic eruption in mesosphere/lower-thermosphere winds derived from CONDOR and the Nordic Meteor Radar Cluster

Stober, G; Liu, AL; Kozlovsky, A; Qiao, ZS; Krochin, W; Shi, GC; Kero, J; Tsutsumi, M; Gulbrandsen, N; Nozawa, S; Lester, M; Baumgarten, K; Belova, E; Mitchell, N

ANNALES GEOPHYSICAE 41 巻 ( 1 ) 頁： 197 - 208 2023年4月

Significant enhancements of the mesospheric Na layer bottom below 75 km observed by a full-diurnal-cycle lidar at Beijing (40.41° N, 116.01° E), China

Xia, Y; Jiao, J; Nozawa, S; Cheng, XW; Wang, JH; Shi, CH; Du, LF; Li, YJ; Zheng, HR; Li, FQ; Yang, GT

ATMOSPHERIC CHEMISTRY AND PHYSICS 22 巻 ( 20 ) 頁： 13817 - 13831 2022年10月

Meteor radar vertical wind observation biases and mathematical debiasing strategies including the 3DVAR+DIV algorithm

Stober, G; Liu, A; Kozlovsky, A; Qiao, ZS; Kuchar, A; Jacobi, C; Meek, C; Janches, D; Liu, GP; Tsutsumi, M; Gulbrandsen, N; Nozawa, S; Lester, M; Belova, E; Kero, J; Mitchell, N

ATMOSPHERIC MEASUREMENT TECHNIQUES 15 巻 ( 19 ) 頁： 5769 - 5792 2022年10月

An automated auroral detection system using deep learning: real-time operation in Tromso, Norway

Nanjo, S; Nozawa, S; Yamamoto, M; Kawabata, T; Johnsen, MG; Tsuda, TT; Hosokawa, K

SCIENTIFIC REPORTS 12 巻 ( 1 ) 2022年5月

狭帯域レーザを用いたナトリウムライダーによる中間圏界面の温度・風速計測招待有り査読有り

川原琢也、野澤悟徳、斎藤徳人、津田卓雄、川端哲也、和田智之

レーザセンシング学会誌 3 巻 ( 1 ) 2022年4月

Atmospheric tomography using the Nordic Meteor Radar Cluster and Chilean Observation Network De Meteor Radars: network details and 3D-Var retrieval

Stober, G; Kozlovsky, A; Liu, A; Qiao, ZS; Tsutsumi, M; Hall, C; Nozawa, S; Lester, M; Belova, E; Kero, J; Espy, PJ; Hibbins, RE; Mitchell, N

ATMOSPHERIC MEASUREMENT TECHNIQUES 14 巻 ( 10 ) 頁： 6509 - 6532 2021年10月

On the temporal evolution of turbopause altitude, 1996-2021, 70°N, 19°E, Experimental Results 査読有り国際共著

Hall, C.M., and S. Nozawa

Experimental Results 2 巻頁： 1 - 7 2021年6月

Formation of an additional density peak in the bottom side of the sodium layer associated with the passage of multiple mesospheric frontal systems 査読有り国際共著

Narayanan, VL; Nozawa, S; Oyama, SI; Mann, I; Shiokawa, K; Otsuka, Y; Saito, N; Wada, S; Kawahara, TD; Takahashi, T

ATMOSPHERIC CHEMISTRY AND PHYSICS 21 巻 ( 4 ) 頁： 2343 - 2361 2021年2月

Statistical study on sporadic sodium layers (SSLs) based on diurnal sodium lidar observations at Beijing, China (40.5 °N, 116 °E) 査読有り国際共著

Xia, Y; Nozawa, S; Jiao, J; Wang, JH; Li, FQ; Cheng, XW; Yang, Y; Du, LF; Yang, GT

JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS 212 巻 2021年1月

OI 630.0-nm and N2 1PG Emissions in Pulsating Aurora Events Observed by an Optical Spectrograph at Tromso, Norway 査読有り国際共著

Tsuda, TT; Li, C; Hamada, S; Hosokawa, K; Oyama, SI; Nozawa, S; Kawabata, T; Mizuno, A; Kurihara, J; Nishiyama, T; Kosch, MJ

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 125 巻 ( 12 ) 2020年12月

A Belt-like Distribution of Gaseous Hydrogen Cyanide on Neptune's Equatorial Stratosphere Detected by ALMA 査読有り

Iino Takahiro, Sagawa Hideo, Tsukagoshi Takashi, Nozawa Satonori

ASTROPHYSICAL JOURNAL LETTERS 903 巻 ( 1 ) 2020年11月

共鳴散乱ライダーによる地球超高層領域の金属原子層の観測

津田卓雄, 野澤悟徳, 斎藤徳人, 川原琢也, 川端哲也, 高橋透、和田智之, 中村卓司, 江尻省, 西山尚典, 津野克彦, 阿保真

レーザー研究 48 巻 ( 11 ) 頁： 580 - 584 2020年11月

Climatology of the main (24-h and 12-h) tides observed by meteor radars at Svalbard and Tromso: Comparison with the models CMAM-DAS and WACCM-X 査読有り国際共著

Pancheva, D; Mukhtarov, P; Hall, C; Meek, C; Tsutsumi, M; Pedatella, N; Nozawa, S; Manson, A

JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS 207 巻 2020年10月

極地から地球環境を計測するためのライダーの開発

和田智之、小川貴代、斎藤徳人、津野克彦、中村卓司、江尻省、野澤悟徳、川端哲也、川原琢也

光技術コンタクト 58 巻 ( 7 ) 頁： 25 - 31 2020年7月

Estimation of the emission altitude of pulsating aurora using the five-wavelength photometer 査読有り

Kawamura, Y; Hosokawa, K; Nozawa, S; Ogawa, Y; Kawabata, T; Oyama, SI; Miyoshi, Y; Kurita, S; Fujii, R

EARTH PLANETS AND SPACE 72 巻 ( 1 ) 2020年7月

Development of low-cost multi-wavelength imager system for studies of aurora and airglow 査読有り国際共著

Ogawa, Y; Tanaka, Y; Kadokura, A; Hosokawa, K; Ebihara, Y; Motoba, T; Gustaysson, B; Brändström, U; Sato, Y; Oyama, S; Ozaki, M; Raita, T; Sigernes, F; Nozawa, S; Shiokawa, K; Kosch, M; Kauristie, K; Hall, C; Suzuki, S; Miyoshi, Y; Gerrard, A; Miyaoka, H; Fujii, R

POLAR SCIENCE 23 巻 2020年3月

High-latitude thermospheric wind study using a Fabry-Perot interferometer at Tromso in Norway: averages and variations during quiet times 査読有り

Xu, H; Shiokawa, K; Oyama, S; Nozawa, S

EARTH PLANETS AND SPACE 71 巻 ( 1 ) 2019年10月

Special issue "Recent Advances in MST and EISCAT/Ionospheric Studies - Special Issue of the Joint MST15 and EISCAT18 Meetings, May 2017" PREFACE 招待有り査読有り国際共著

Yamamoto, M; Hocking, WK; Nozawa, S; Vierinen, J; Liu, HX; Nishitani, N

EARTH PLANETS AND SPACE 71 巻 ( 1 ) 2019年9月

On the Long Lasting "C-Type" Structures in the Sodium Lidargram: The Lifetime of Kelvin-Helmholtz Billows in the Mesosphere and Lower Thermosphere Region 査読有り国際共著

Mondal, S; Sarkhel, S; Agarwal, J; Chakrabarty, D; Sekar, R; Yuan, T; Cai, XG; Liu, AZ; Nozawa, S; Saito, N; Kawahara, TD; Mlynczak, MG; Russell, JM

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 124 巻 ( 4 ) 頁： 3110 - 3124 2019年4月

Survey of conditions for artificial aurora experiments by the second electron gyro-harmonic at EISCAT Tromso using dynasonde data

Tsuda, TT; Rietveld, MT; Kosch, MJ; Oyama, S; Ogawa, Y; Hosokawa, K; Nozawa, S; Kawabata, T; Mizuno, A

EARTH PLANETS AND SPACE 70 巻 2018年6月

Survey of conditions for artificial aurora experiments at EISCAT Tromso using dynasonde data

Tsuda, TT; Rietveld, MT; Kosch, MJ; Oyama, S; Hosokawa, K; Nozawa, S; Kawabata, T; Mizuno, A; Ogawa, Y

EARTH PLANETS AND SPACE 70 巻 2018年3月

Evaluation of a method to derive ionospheric conductivities using two auroral emissions (428 and 630 nm) measured with a photometer at Tromso (69.6° N)

Adachi, K; Nozawa, S; Ogawa, Y; Brekke, A; Hall, C; Fujii, R

EARTH PLANETS AND SPACE 69 巻 2017年7月

Sodium temperature/wind lidar based on laser-diode-pumped Nd:YAG lasers deployed at Tromso, Norway (69.6°N, 19.2°E)

Kawahara, TD; Nozawa, S; Saito, N; Kawabata, T; Tsuda, TT; Wada, S

OPTICS EXPRESS 25 巻 ( 12 ) 頁： A491 - A501 2017年6月

Measurement of thermospheric temperatures using OMTI Fabry-Perot interferometers with 70-mm etalon

Nakamura, Y; Shiokawa, K; Otsuka, Y; Oyama, S; Nozawa, S; Komolmis, T; Komonjida, S; Neudegg, D; Yuile, C; Meriwether, J; Shinagawa, H; Jin, H

EARTH PLANETS AND SPACE 69 巻 2017年4月

Sodium temperature/wind LIDAR based on laser-diode-pumped Nd:Yag lasers deployed at Tromsø, Norway (69.6°, 19.2°) 査読有り

Kawahara, T.D., S. Nozawa, N. Saito, T, Kawabata, T.T. Tsuda, and S. Wada,

Optics Express 25 巻 ( 12 ) 頁： A491-A501 2017年4月

Depletion of mesospheric sodium during extended period of pulsating aurora

Takahashi, T; Hosokawa, K; Nozawa, S; Tsuda, TT; Ogawa, Y; Tsutsumi, M; Hiraki, Y; Fujiwara, H; Kawahara, TD; Saito, N; Wada, S; Kawabata, T; Hall, C

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 122 巻 ( 1 ) 頁： 1212 - 1220 2017年

A proposal on the study of solar-terrestrial coupling processes with atmospheric radars and ground-based observation network 査読有り

Tsuda, T., M. Yamamoto, H. Hashiguchi, K. Shiokawa, Y. Ogawa, S. Nozawa, H. Miyaoka, and A. Yoshikawa

Radio Sci. 51 巻 ( 9 ) 頁： 1587-1599 2016年7月

Change in turbopause altitude at 52 and 70 deg N 査読有り

Hall, C. M., S. E. Holmen, C. E. Meek, A. H. Manson, and S. Nozawa

Atmos. Chem. Phys. 16 巻頁： 2299-2308 2016年2月

A sporadic sodium layer event detected with five-directional lidar and simultaneous wind, electron density, and electric field observation at Tromsø, Norway 査読有り

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

Geophys. Res. Lett. 42 巻頁： 9190-9196 2015年11月

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

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

Ann. Geophys. 33 巻頁： 941-953 2015年8月

Statistical study of auroral fragmentation into patches 査読有り

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

J. Geophys. Res. 120 巻頁： 6207-6217 2015年7月

Mesospheric and thermospheric observations of the January 2010 stratospheric warming event 査読有り

Wu, Q. and S. Nozawa

Journal of Atmospheric and Solar-Terrestrial Physics 123 巻頁： 22-38 2015年2月

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

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. 32 巻頁： 1195-1205 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.-I. Oyama, S. Nozawa, K. McWilliams

J. Geophys. Res. 119 巻頁： 8249-8261 2014年9月

Extreme ion heating in the dayside ionosphere in response to arrival of a coronal mass ejection on March 12, 2012 査読有り

Fujiwara, H., S. Nozawa, Y. Ogawa, R. Kataoka, Y. Miyoshi, H. Jin, and H. Shinagawa

Ann. Geophys. 32 巻頁： 831-839 2014年7月

Upper Atmosphere cooling over the past 33 years 招待有り査読有り

Ogawa, Y., T. Motoba, S. C. Buchert, I. Häggström and S. Nozawa

Geophys. Res. Lett. 41 巻頁： 5629-5635 2014年7月

Variations of the neutral temperature and sodium density between 80 and 107 km above Tromso during the winter of 2010-2011 by a new solid state sodium LIDAR 査読有り

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

Journal of Geophysical Research 119 巻 ( 1 ) 頁： 441-451 2014年1月

Relationship between auroral substorm and ion upflow in the nightsidem polar ionosphere 査読有り

Ogawa, Y., M. Sawatsubashi, S. C. Buchert, K. Hosokawa, S. Taguchi, S. Nozawa, S. Oyama, T. T. Tsuda, and R. Fujii

J. Geophys. Res. 118 巻頁： 7426-7437 2013年11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. Nozawa, and T. T. Tsuda

Antarctic Record 57 巻 ( 3 ) 頁： 339-356 2013年11月

Decrease in sodium density observed during auroral particle precipitation over Tromsø 査読有り

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. Lett. 40 巻頁： 4486-4490 2013年8月

Field-Aligned Current Loop Model on Formation of Sporadic Metal Layers, 査読有り

Matuura, N., T. Tsuda, and S. Nozawa

J. Geophys. Res. 118 巻 2013年6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. Connor

103 巻頁： 184-194 2013年4月

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

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

Earth Planets Space 64 巻頁： 1033-1046 2012年11月

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

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

Journal of Geophysical Research 117 巻 ( A10 ) 頁： 2012JA017928 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, R. Fujii

JASTP 90-91 巻頁： 26-44 2012年5月

Velocity of E-region HF echoes under strongly-driven electrojet conditions 査読有り

Gorin, J. D., A. V. Koustov1, R. A. Makarevich2, J.-P. St.-Maurice1, and S. Nozawa

Ann. Geophys. 30 巻頁： 235-250 2012年1月

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

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

Geophys. Res. Lett. 38 巻 2011年9月

Angular dependence of pump-induced bottom- and top-side ionospheric plasma turbulence at EISCAT 査読有り

Kosch, M., E. Mjolhus, M. Ashrafi, M. Rietveld, T. Yeoman, S. Nozawa

J. Geophys. Res. 116 巻 2011年3月

記述言語：英語掲載種別：研究論文（学術雑誌）

We experimentally observe the location and angular size of the high-frequency (HF) radio window in the bottomside ionosphere, which permits radio wave propagation to the topside ionosphere, with high angular resolution at the European Incoherent Scatter (EISCAT) facility. HF pump-induced ion line enhancements were observed by the EISCAT UHF incoherent scatter radar on the ionospheric bottomside and topside.

DOI： 10.1029/2010JA016014

Meso-scale observations of Joule heating near an auroral arc and ion-neutral collision frequency in the polar cap E-region 査読有り

Kosch, M., Ho-Ching Iris Yiu, Callum Anderson, Takuo Tsuda, Yasunobu Ogawa, Satonori Nozawa, Anasuya Aruliah, Victoria Howells, Lisa Baddeley, Ian McCrea, James Wild

J. Geophys. Res. 116 巻 2011年3月

On the statistical relation between ion upflow and naturally enhanced ion-acoustic lines observed with the EISCAT Svalbard radar 査読有り

Ogawa, Y., S. C. Buchert, I. Haggstrom, M. T. Rietveld, R. Fujii, S. Nozawa, and H. Miyaoka

J. Geophys. Res. 116 巻 2011年3月

Horizontal structure of sporadic E layer observed with a rocket-borne magnesium ion imager 査読有り

Kurihara, J., Y. Koizumi-Kurihara, N. Iwagami, T. Suzuki, A. Kumamoto, T. Ono, M. Nakamura, M. Ishii, A. Matsuoka, K. Ishisaka, T. Abe, and S. Nozawa

J. Geophys. Res. 115 巻 ( A12318 ) 頁： 10.1029/2009JA014926 2010年12月

記述言語：英語掲載種別：研究論文（学術雑誌）

To study the spatial structure of midlatitude sporadic E (Es) layers, the ultraviolet resonant scattering by magnesium ions (Mg+) in an Es layer was observed during the evening twilight with the Magnesium Ion Imager (MII) on the sounding rocket launched from the Uchinoura Space Center in Kagoshima, Japan. The in situ electron density measured by an onboard impedance probe showed that the Es layer was located at an altitude of 100 km during both the ascent and descent of the flight. Simultaneous observation with a ground-based ionosonde at Yamagawa identified the signature of horizontally “patchy" structures in the Es layer. The MII successfully scanned the horizontal Mg+ density perturbations in the Es layer and found that they had patchy and frontal structures. The horizontal scale and alignment of the observed frontal structure is generally consistent with a proposed theory. To our knowledge, this is the first observation of the two-dimensional horizontal structure of Mg+ in an Es layer.

An analysis of pump-induced artificial ionospheric ion upwelling at EISCAT 査読有り

Kosch, M., Y. Ogawa, M. Rietveld, S. Nozawa, and R. Fujii

J. Geophys. Res. 115 巻 ( A12317 ) 頁： 10.1029/2010JA015854 2010年12月

記述言語：英語掲載種別：研究論文（学術雑誌）

Ion outflow from the high‐latitude ionosphere is a well‐known phenomenon and an important source of plasma for the magnetosphere. It is also well known that pumping the ionosphere with high‐power high‐frequency radio waves causes electron heating. On a few occasions, this has been accompanied by artificially induced ion upwelling. We analyze such a controlled experiment at EISCAT up to 600 km altitude. The pump‐enhanced electron temperatures reached up to ∼4000 K above 350 km, and ion upwelling reached up to ∼300 m/s above 500 km altitude. The pump‐induced electron pressure gradient can explain the ion velocity below 450 km. Between 450 and 600 km the electron pressure gradient correlates equally with ion acceleration and ion velocity, which represents the transition altitude to free ion acceleration. The electron gas pressure gradient can explain ion upwelling, at least up to 600 km altitude. In addition, such active experiments open the possibility to estimating the F layer ion‐neutral collision frequency and neutral density with altitude from ground‐based observations.

Lower-thermospheric wind fluctuations measured with an FPI in pulsating aurora at Tromsoe 査読有り

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

Ann. Geophys. 28 巻 ( 10 ) 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 1 Introduction 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 au- rora. The lower-thermospheric wind velocity measured with the FPI showed obvious fluctuations in both vertical and hor- izontal 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 pres- ence 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 per- turbations may be responsible for the increase in ionospheric thermal energy thus modifying the local wind dynamics in the lower thermosphere.

Tidal waves in the polar lower thermosphere using the EISCAT long run data set obtained in September 2005 査読有り

Nozawa, S, Y. Ogawa, S. Oyama, H. Fujiwara, T. Tsuda, A. Brekke, C. Hall , Y. Murayama, S. Kawamura, H. Miyaoka, and R. Fujii

J. Geophys. Res. 115 巻 2010年8月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

Characteristics are presented of the lower thermospheric wind from a long run data set obtained by the EISCAT UHF radar at Tromsø (69.6°N, 19.2°E) over ~23 days, from September 6 to 29, 2005. The derived semidiurnal amplitude exhibited day-to-day variations (~5–30 ms-1) at and above 109 km, while the phase varied little with the day. We have found a mode change of the semidiurnal tide occurring during September 17–22, 2005. Between September 6 and 16, the vertical wavelengths were estimated to be ~58 km and ~76 km for the meridional and zonal components, respectively, while between September 23 and 29, they became less than ~24 km. The day to day variability of the diurnal tide was less obvious than that of the semidiurnal tide. The diurnal amplitude of the meridional component increased with height except for 8 days between September 13 and 20, when the diurnal amplitudes were smaller values (<40 ms-1) at and above 111 km than those for the other intervals. Furthermore, the shapes of the altitude profiles of the meridional phase differ from those for the other intervals. We have evaluated contributions due to the electric field and the ion drag acceleration and showed that they were not the causes. From the analysis of 22.5 days of wind data, we found about 5–6 day oscillations in the lower thermosphere, probably where there were planetary wave activities in the lower thermosphere.

Solar activity dependence of ion upflow in the polar ionosphere observed with the EISCAT Tromsø UHF radar 査読有り

Ogawa, Y., S. C. Buchert, A. Sakurai, S. Nozawa, R. Fujii

J. Geophys. Res., 115 巻頁： doi:10.1029/2009JA014766 2010年7月

記述言語：英語掲載種別：研究論文（学術雑誌）

The influence of solar activity upon ion upflow in the polar ionosphere was investigated using data obtained by the European Incoherent Scatter (EISCAT) Tromsø UHF radar between 1984 and 2008. In agreement with other work we find that the upward ion flux is generally higher when solar activity is high than when it is low. Ion upflow events and also the upward velocity behave the opposite: they are more frequently seen and higher, respectively, at times of low solar activity. In any year about 30–40% ion upflow is accompanied by ~500 K higher electron temperature than the background temperature at 400 km altitude. Electron and ion heating in connection with upflow is nearly twice as prevalent during high solar activity as it is at low activity. The acceleration of ions by pressure gradients and ambipolar electric field becomes larger when solar activity is low than when it is high. This variation of the average acceleration is caused by the different shapes of electron density profiles for low and high solar activities. Ions start to flow up at above 450 km altitude when solar activity was high, and lower, at 300–500 km altitude, at low solar activity. It is suggested that the solar activity influences long-term variations of the ion upflow occurrence because it modulates the density of neutral particles, the formation of the F2 density peak, and ion-neutral collision frequencies in the thermosphere and ionosphere.

Links between a stratospheric sudden warming and thermal structures and dynamics in the high-latitude mesosphere, lower thermosphere 査読有り

Kurihara, J., Y. Ogawa, S. Oyama, S. Nozawa, M. Tsutsumi, C. M. Hall, Y. Tomikawa, and R. Fujii

Geophys. Res. Lett. 37 巻 ( L13806 ) 頁： doi:10.1029/2010GL043643 2010年7月

記述言語：英語掲載種別：研究論文（学術雑誌）

We analyzed neutral winds, ambipolar diffusion coefficients, and neutral temperatures observed by the Nippon/Norway Tromsø Meteor Radar (NTMR) and ion temperatures observed by the European Incoherent Scatter (EISCAT) UHF radar at Tromsø (69.6°N, 19.2°E), during a major stratospheric sudden warming (SSW) that occurred in January 2009. The zonal winds at 80–100 km height reversed approximately 10 days earlier than the zonal wind reversal in the stratosphere and the neutral temperature at 90 km decreased simultaneously with the zonal wind reversal at the same altitude. We found different variations between geomagnetically quiet nighttime ion temperatures at 101–110 km and 120–142 km for about 10 days around the SSW. Our results from the ground-based observations agree well with the satellite observations shown in an accompanying paper. Thus, this study indicates that a SSW is strongly linked to thermal structure and dynamics in the high-latitude mesosphere, lower thermosphere, and ionosphere.

Temperature enhancements and vertical winds in the lower thermosphere associated with auroral heating during the Dynamics and Energetics of the Lower Thermosphere in Aurora (DELTA) campaign 査読有り

Kurihara, J., S. Oyama , S. Nozawa , T. Tsuda , R. Fujii , Y. Ogawa , H. Miyaoka , N. Iwagami , T. Abe , K.-I. Oyama , M. Kosch , A.L. Aruliah , E. Griffin , K. Kauristie

J. Geophys. Res. 114 巻頁： A12306, doi:10.1029/2009JA014392 2009年12月

記述言語：英語掲載種別：研究論文（学術雑誌）

A coordinated observation of the atmospheric response to auroral energy
input in the polar lower thermosphere was conducted during the Dynamics and
Energetics of the Lower Thermosphere in Aurora (DELTA)
campaign. N2 rotational temperature was measured with a rocket-borne
instrument launched from the Andoya Rocket Range, neutral winds were
measured from auroral emissions at 557.7 nm with a Fabry-Perot
Interferome-ter (FPI) at Skibotn and the KEOPS, and ionospheric parameters
were measured with the European Incoherent Scatter (EISCAT) UHF radar at
Tromso. Altitude profiles of the passive energy deposition rate and the
particle heating rate were estimated using data taken with the EISCAT radar.
The local temperature enhancement derived from the difference between the
observed N2 rotational temperature and the MSISE-90 model neutral
temperature were 70-140 K at 110-140 km altitude. The temperature increase
rate derived from the estimated heating rates, however, cannot account for
the temperature enhancement below 120 km, even considering the contribution
of the neutral density to the estimated heating rate. The observed upward
winds up to 40 m s¡1 seem to respond nearly instantaneously to changes in
the heating rates. Although the wind speeds cannot be explained by the
estimated heating rate and the thermal expansion hypothesis, the present
study suggests that the generation mechanism of the large vertical winds
must be responsible for the fast response of the vertical wind to the
heating event.

On the source of the polar wind in the polar topside ionosphere: First results from the EISCAT Svalbard radar 査読有り

Ogawa, Y., I. Häggström, S. C. Buchert, K. Oksavik, S. Nozawa, M. Hirahara, A. P. van Eyken, T. Aso, and R. Fujii

Geophysical Research letters 36 巻頁： L24103, doi:10.1029/2009GL041501 2009年12月

記述言語：英語掲載種別：研究論文（学術雑誌）

We present quantitative radar observations of both hydrogen ion (H+) and oxygen ion (O+) upflow in the topside polar ionosphere using measurements that were recently carried out with the EISCAT Svalbard Radar and the Reimei satellite. H+ upflow was clearly observed equatorward of the cusp above 500 km altitude. Within the cusp the H+ density was very low, and the upflow was dominated by O+ ions, but on closed field lines the H+ became the larger contributor to the upward flux above about 550 km. The total flux seemed to be conserved, and so below 550 km altitude O+ (with a small upward velocity of ~50 m s–1) appeared to determine the upward flux which was then maintained by H+ in the topside ionosphere. We also found that the H+ density in the topside polar ionosphere was several times higher than current predictions of ionospheric models like IRI2001

Ion heating in high-speed flow channel within the duskside cell of the polar-cap ion convection under large IMF-By 査読有り

Maeda, S, Y. Ogawa, K. Hosokawa, S. Nozawa, S. Oyama, T. Tsuda, and A. Brekke

J. Geophys. Res 114 巻頁： 10.1029/2009JA014300 2009年11月

記述言語：英語掲載種別：研究論文（学術雑誌）

F region strong sunward ion flow embedded in the duskside cell of expanding polar cap ion convection and coincidental increase in the ion temperature were observed from about 73 degrees to 69 degrees in geomagnetic latitude between 16: 00 and 16: 48 MLT on 19 August, 2006 from an experiment using the European Incoherent Scatter (EISCAT) radars at Tromso, Sodankyla and Longyearbyen together with the CUTLASS HF radars. The spatiotemporal structure of the convection map obtained by the SuperDARN HF radars showed that the high-speed flow channel elongated in 14-17 MLT was moving equatorward. The flow channel appeared during an interval of negative interplanetary magnetic field B-z associated with large positive B-y. In order to evaluate ion frictional heating and resultant ion temperature increase quantitatively, the experiment was conducted to estimate the ion velocity vector and the ion temperature at the common scattering volume of the EISCAT radars. While the flow channel moved equatorward, the ion temperature increase became less evident at higher part of latitudes within the flow channel, which means that ion frictional heating was depressed where the neutral gases had already responded to the high-speed ions. The increase in the ion temperature at particular geomagnetic latitude continued for about 20 min, and then ceased while the ion velocity was still enhanced. Ion frictional heating lasted until the neutral wind was accelerated to the equivalent level of the surrounded ion flow.

Relations between proton auroras, intense electric field, and ionospheric electron density depletion 査読有り

Fujii, R., Y. Iwata, S. Oyama, S. Nozawa, and Y. Ogawa

J. Geophys. Res. 114 巻頁： 10.1029/2009JA014319 2009年9月

記述言語：英語掲載種別：研究論文（学術雑誌）

A case study with simultaneous European Incoherent Scatter and optical auroral observations was conducted in order to determine characteristics of the magnetosphere-ionosphere coupling from the viewpoint of the electrodynamics in the ionosphere. Particularly focused on were the relationships between ionospheric electron density depletion, perpendicular electric fields, and proton auroras. Intense electron density depletion was observed in the E and F regions poleward and in the vicinity of a thin equatorward moving arc. This depletion was associated with an intense, equatorward perpendicular electric field close to similar to 80 mV/m and most likely with a downward field-aligned current (FAC), but it did not accompany detectable proton aurora. Hence the downward FA electric field in the lower magnetosphere associated with this depletion was weak or absent. The motion of the FAC system with the depletion and the arc presumably enabled the downward FAC to obtain enough current carriers as ionospheric electrons were lost by the evacuation process. The evacuation process associated with the downward FAC was, however, efficient enough to establish the depletion. On the other hand, a widely distributed proton aurora observed immediately after the depletion was associated with an intense, equatorward perpendicular electric field close to 90 mV/m, enhanced electron density, and most likely a downward FAC. No electron precipitation was associated with this proton aurora. Thus the electron density enhancement, providing the downward current carriers, had to be caused by the ionization of precipitating protons presumably accelerated by downward field-aligned electric fields in the lower magnetosphere.

Spatial evolution of frictional heating and the predicted thermospheric wind effects in the vicinity of an auroral arc measured with the Sondrestrom incoherent-scatter radar and the Reimei satellite 査読有り

Oyama, S., T. T. Tsuda, T. Sakanoi, Y. Obuchi, K. Asamura, M. Hirahara, A. Yamazaki, Y. Kasaba, R. Fujii, S. Nozawa, and B. J. Watkins

J. Geophys. Res 114 巻頁： 10.1029/2009JA014091 2009年7月

記述言語：英語掲載種別：研究論文（学術雑誌）

Simultaneous observation with the Sondrestrom incoherent-scatter (IS) radar and the Reimei satellite was conducted on 3 October 2007. The objective was to measure horizontal patterns of the ionospheric structure in the vicinity of an auroral arc. The IS radar was scanned azimuthally with a fixed elevation angle, and the satellite narrow-view camera (557.7 nm) was directed downward taking pictures every 0.12 s. A stationary auroral arc was captured at 05: 17 UT (02: 54 MLT) with both instruments simultaneously. Gross ionospheric features measured with the IS radar around the arc were in good agreement with the expected magnetosphere-ionosphere current system. Of particular interest was the horizontal pattern in the ion speed and temperature in the F region. The ion speed within the arc was close to zero; by contrast the larger ion speed (350-400 m s(-1)) on the poleward side was parallel to the arc and almost no horizontal shear within about 20 km width perpendicular to the arc. This area was separated into two parts by the ion temperature: one was associated with clear enhancements in excess of 1200 K, and another was with more moderate enhancements (less than similar to 1000 K). The widths of the two areas were approximately 10 km each. The horizontal shear seen in the ion temperature suggested the presence of a narrow thermospheric wind shear of about 10 km width. This paper suggests that the possible cause for the thermospheric wind shear was ion drag associated with localized soft particle precipitation or F-region ionization.

Characteristics of ion upflow and downflow observed with the European Incoherent Scatter Svalbard radar 査読有り

Ogawa, Y. S. C. Buchert, R. Fujii, S. Nozawa, and A. P. van Eyken

J. Geophys. Res. 114 巻頁： 10.1029/2008JA013817 2009年5月

記述言語：英語掲載種別：研究論文（学術雑誌）

We have investigated how geomagnetic activity, the solar wind (SW), and the interplanetary magnetic field (IMF) influence the occurrence of the F-region/topside ionospheric ion upflow and downflow. Occurrence of dayside ion upflow observed with the European Incoherent Scatter Svalbard radar (ESR) at 75.2 degrees magnetic latitude is highly correlated with the SW density, as well as with the strength of the IMF By component. We suggest that this correlation exists because the region where ion upflow occurs is enlarged owing to SW density and IMF By magnitude, but it does not move significantly in geomagnetic latitude. The occurrence frequency of dayside ion upflow displays peaks versus the geomagnetic activity index (Kp), SW velocity, and negative IMF Bz component; that is, ion upflow is less frequently seen at the highest values of these parameters. Dayside ion downflow in the F-region/topside ionosphere occurs only when the Kp index and/or SW velocity are high or when IMF Bz is largely negative. The ion downflow is likely due to ballistic return of the ion upflow. We suggest that the region of ion upflow not only becomes larger but also moves equatorward with increasing Kp, SW velocity, and negative IMF Bz. The ESR can so be poleward of the upflow region and observe ions convecting poleward and returning ballistically downward.

*Acceleration mechanism of high-speed neutral wind observed in the polar lower thermosphere 査読有り

Tsuda, T. T., Satonori Nozawa , Shin Oyama , Tetsuo Motoba , Yasunobu Ogawa , Hiroyuki Shinagawa , Nozomu Nishitani , Keisuke Hosokawa , Natsuo Sato , Mark Lester , Ryoichi Fujii

J. Geophys. Res. 114 巻頁： doi:10.1029/2008JA013867 2009年4月

記述言語：英語掲載種別：研究論文（学術雑誌）

e analyzed data obtained with the European incoherent scatter (EISCAT) Svalbard Radar (ESR) at Longyearbyen (78.2 degrees N, 16.0 degrees E in geographic coordinates, 75.2 degrees Lambda in invariant latitude) to advance our understanding of the acceleration mechanism of the lower thermospheric neutral wind when the ionospheric convection becomes enhanced. The Advanced Composition Explorer satellite observed a southward turning in the interplanetary magnetic field at 0843 UT on 16 June 2005. At 0900 UT, the F region ion velocity and the lower thermospheric neutral wind ( at 118-km altitude) observed with the ESR began to accelerate significantly in the westward and northwestward directions, respectively. The neutral wind was remarkably accelerated within 1 hour from 0900 UT, and its speed became a value of similar to 500 m s(-1) at 1000 UT. The wind speed was significantly higher than a typical wind speed at 118 km. We evaluated the ion drag contribution on the generation of the high-speed neutral wind. Our evaluation verifies that the ion drag force could not generate the high- speed neutral wind within such a short time (similar to 1 hour). This result implies that the major driving force was the horizontal pressure gradient force induced by the Joule heating. We deduced the contribution of the pressure gradient force based on a quantitative estimation of the Joule-heating-induced pressure gradient from the ESR and the Super Dual Auroral Radar Network data. We concluded that the pressure gradient force was the most probable force in this event.

Coordinated EISCAT Svalbard radar and Reimei satellite observations of ion upflows and suprathermal ions 査読有り

Ogawa, Y., K. Seki, M. Hirahara, K. Asamura, T. Sakanoi, S. C. Buchert, Y. Ebihara, Y. Obuchi, A. Yamazaki, I. Sandahl, S. Nozawa, and R. Fujii

J. Geophys. Research 113 巻頁： doi:10.1029/2007JA012791 2008年

The Pedersen current carried by electrons: A non-linear response of the ionosphere to magnetospheric forcing 査読有り

Buchert, S., T. Tsuda, R. Fujii, and S. Nozawa

Annales Geophysicae 26 巻頁： 2837–2844 2008年

Generation of the lower-thermospheric vertical wind estimated with the EISCAT KST radar at high latitudes during periods of moderate geomagnetic disturbance, 査読有り

Oyama, S.m B. J. Watkins, S. Maeda, H. Shinagawa, S. Nozawa, Y. Ogawa, A. Brekke, C. Lathuillere, and W. Kofman

Annales Geophysicae 26 巻頁： 1491-1505 2008年

Turbopause determination, climatology and climatic trends, using medium frequency radars at 52º and 70ºN 査読有り

Hall, C., C. Meek, A. Manson, S. Nozawa

J. Geophys. Research 113 巻頁： doi:10.1029/2008JD009938 2008年

Mesospheric turbulence during PMWE-conducive conditions 査読有り

C. M. Hall, A. H. Manson, C. E. Meek, and S. Nozawa

Atmos. Chem. Phys. Discuss 7 巻頁： 7035-7049 2007年5月

掲載種別：研究論文（学術雑誌）

Strong radar returns at VHF known as Polar Mesospheric Winter Echoes (PMWE) seem to occur during periods of intense ionisation of the mesosphere. Apart from a
mechanism to produce such ionisation, viz. solar proton precipitation, other prerequisites have been proposed, such as neutral air turbulence. Here, we employ a medium
frequency radar to examine whether the atmospheric state is conducive to the appearance
of PMWE; echo power signatures (isolated lower mesospheric echoes – “ILME")
are indicators of the necessary ionisation at sufficient depth in the middle atmosphere,
and also echo fading times give information on turbulence. We fail to find evidence for causal relationship between ILME and turbulence but suggest that on occasion turbulence
may be enhanced related to proton precipitation. The results presented provide
a basis for investigating whether turbulence is a prerequisite for PMWE.

*夏期極冠域における下部熱圏へのイオンドラッグ効果査読有り

津田　卓雄、野澤　悟徳、アスゲイア　ブレッケ、元場　哲郎、レイ　ローブル、藤井良一

112 巻頁： A06319, doi:10.1029/2006JA011785 2007年

記述言語：英語掲載種別：研究論文（学術雑誌）

1999年7月1-7日に6日間連続してトロムソおよびロングイアビンのEISCATレーダーにより取得されたデータを解析して、イオンドラッグ効果の下部熱圏大気ダイナミクスへの影響を観測データに基づいて定量的に評価をした。ロングイアビンにおいて、１日周期で変動する電場により、１日周期の大気風変動が有為に増幅されていることが分かった。さらにNCAR TIME-GCMを用いて、イオンドラッグ効果を検証した。

EISCAT・CUTLASSレーダー観測による極域上部熱圏領域での電磁エネルギー散逸率の推定査読有り

藤原　均、片岡龍峰、鈴木美代子、前田佐和子、野澤悟徳、細川敬祐、福西　浩、佐藤夏雄、マークレスター

25 巻頁： 2393-2403 2007年

北緯70度における中間圏乱流のトレンド査読有り

クリス　ホール、アスゲイア　ブレッケ、アラン　マンソン、クリス　ミーク、野澤悟徳

大気科学レター 8 巻頁： 80-84 2007年

デルタキャンペーン時におけるEISCATレーダー観測結果査読有り

野澤悟徳、小川泰信、アスゲイア　ブレッケ、津田卓雄、クリス　ホール、宮岡宏、栗原純一、阿部琢美、藤井良一

58 巻頁： 1183-1192 2006年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

2004年12月の行われたデルタロケットキャンペーン中におけるトロムソEISCATレーダーにより観測された電離圏の活動についてまとめた。半日大気潮汐波の日々変動が大きいことを示した。さらに、デルタロケットおよびEISCATレーダーにより観測／導出された中性（イオン）温度および電子温度の比較結果を示した。

高高度で観測されるイオン音波擾乱の研究査読有り

小川泰信、ステファン　ブハート、藤井良一、野澤悟徳、フランソワ　フォルム

24 巻頁： 3351-3364 2006年

記述言語：英語掲載種別：研究論文（学術雑誌）

1200-1900 kmの高度で生じるイオン音波擾乱をスヴァールバルレーダーを用いて新たに発見し、特徴を調べた。その結果（１）高度 1500 km 付近ではイオンドリフト速度がイオン音波の速度の半分に達すること、（２）降下粒子に加え上方伝搬するプラズマ波動により電離圏電子が加熱されている可能性を明らかにした。この結果は高高度電離圏における波動粒子相互作用を理解する上で極めて重要な結果である。

中間圏下部にてMFレーダー（北緯70度、東経19度）で見られた孤立エコー査読有り

クリス　ホール、アラン　マンソン、クリス　ミーク、野澤悟徳

6 巻頁： 5307-5314 2006年

大きなフロー角度時におけるSTARE速度：イオン音波速度と関係？査読有り

24 巻頁： 873-885 2006年

オーロラ下部熱圏におけるダイナミクス／エネジェティクス～日本ロケットキャンペーン査読有り

阿部琢美、栗原純一、岩上直幹、野澤悟徳、小川泰信、藤井良一、早川基、小山孝一郎

58 巻頁： 1161-1171 2006年

中間圏乱流における潮汐波の徴候査読有り

クリス　ホール、野澤悟徳、アラン　マンソン、クリス　ミーク

24 巻頁： 453-465 2006年

北緯70度における流星レーダーおよびMFレーダーにより得られたキロメートルスケールのMLTダイナミクスの比較査読有り

クリス　ホール、麻生武彦、堤雅基、野澤悟徳、クリス　ミーク、アラン　マンソン

68 巻頁： 309-316 2006年

Comparative study of the high-latitude E-region ion and neutral temperatures in the polar cap and the auroral region derived from the EISCAT radar observations 査読有り

Maeda, S., S. Nozawa, H. Fujiwara, and Y. Ogawa

J. Geophys. Res. 110 巻 ( A08301 ) 頁： 10.1029/2004JA010893 2005年

*2003年11月における８日連続観測データに基づく北極域下部熱圏における、平均風、大気潮汐波、準２日波の研究査読有り

野澤悟徳、アスゲイア　ブレッケ、前田佐和子、麻生武彦、クリス　ホール、小川泰信、ステファン　ブハート、ユルゲン　レッドガー、アート　リッチモンド、レイ　ローブル、藤井良一

110 巻頁： A12309, doi:10.1029/2005JA0011128 2005年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

下部熱圏大気に関する知見を増やすために、2003年11月11日から19日に、トロムソ（北緯69.6度）およびロングイアビン（北緯78.2度）にあるEISCATレーダーを用いたキャンペーン観測を実施した。その結果、冬期下部熱圏では、準２日波が存在しないこと、半日周期大気潮汐波の強度がロングイアビンにおいても強いこと、イオンドラッグ効果が下部熱圏においても時に重要になることが分かった。

Statistical height-dependent relative importance of the Lorentz force and Joule heating in generating atmospheric gravity waves in the auroral electrojets 査読有り

Yuan, Zhigang, Ryoichi Fujii, Satonori Nozawa, Y. Ogawa

J. Geophys. Res. 110 巻頁： A12303,doi:10.1029/2005JA011315 2005年

Testing the hypothesis of neutral turbulence on the deduction of ambipolar diffusivities from meteor trail expansion 査読有り

Hall, C. M., T. Aso, M. Tsutsumi , S. Nozawa, A.H. Manson, and C.E. Meek

Ann. Geophisicae Letter 23 巻頁： 1071-1073 2005年

北緯70度に設置されている流星レーダーおよびMFレーダーにより導出されたMLT中性風の比較査読有り

クリス　ホール、麻生武彦、堤雅基、野澤悟徳、アラン　マンソン、クリス　ミーク

40 巻頁： RS4001, doi:10.1029/2004RS003102 2005年

Vertical ion motions observed with incoherent-scatter radars in the polar lower ionosphere 査読有り

Oyama, S., B. J. Watkins, S. Nozawa, S. Maeda, and M. Conde

J. Geophys. Res 110 巻頁： A04302, doi:10.1029/2004JA010705 2005年

Arctic and Antarctic polar mesosphere summer echoes observed with oblique incidence HF radars: Analysis using simultaneous MF and VHF radar data 査読有り

Ogawa, T., S. Nozawa, M. Tsutsumi, N. F. Arnold, N. Nishitani, N. Sato, and A. S. Yukimatu

Ann. Geophysi. 22 巻 ( 12 ) 頁： 4,049-4,059 2004年12月

Monthly mean climatology of the prevailing winds and tides in the Arctic mesosphere/lower thermosphere 査読有り

Portnyagin Y. I. , T. V. Solovjova, N. A. Makarov, E. G. Merzlyakov, A. H. Manson, C. E. Meek, W. Hocking, N. Mitchell, D. Pancheva, P. Hoffmann, W. Singer, Y. Murayama, K. Igarashi, J. M. Forbes, S. Palo, C. Hall, S. Nozawa

Ann. Geophys. 22 巻頁： 3395-3410 2004年

MESOPAUSE DYNAMICS FROM THE SCANDINAVIAN TRIANGLE OF RADARS WITHIN THE PSMOS-DATAR PROJECT 査読有り

Manson, A. H., C.E. Meek, C.M. Hall, S. Nozawa, N.J. Mitchell, D. Pancheva, W. Singer, and P. Hoffmann

Ann. Geophysi. 22 巻頁： 367-386 2004年

Estimates of electromagnetic and turbulent energy dissipation rates under the existence of strong wind shears in the polar lower thermosphere from the EISCAT Svalbard radar observations 査読有り

Fujiwara, H., S. Maeda, M. Suzuki, S. Nozawa, and H. Fukunishi

Journal of Geophysical Research 109 巻頁： A07306, doi:10.1029/2003JA010046 2004年

STARE Velocities: Importance of Off-Orthogonality and Ion Motions 査読有り

Uspensky, M., A. Koustov, P. Janhunen, R. Pellinen, D. Danskin, and S. Nozawa

Ann. Geophysi. 21 巻頁： 729-743 2003年

Periodicities in energy dissipation rates in the auroral mesosphere / lower thermosphere 査読有り

Hall, C.M, S. Nozawa, C. E. Meek, A. H. Manson, and Yi Luo

Ann. Geophysi. 21 巻頁： 787-796 2003年

EISCAT スヴァルバールレーダーと DMSP 衛星による昼側電離圏イオン上昇流の同時観測査読有り

108 巻頁： 10.1029/2002JA009590, SIA 1-1 － 1-10 2003年

Observations of mesospheric neutral wind 12-hour wave in the Northern Polar Cap 査読有り

Wu, Q., T. K. Kileen, S. Nozawa, D. McEwen, W. Guo, and S. C. Solomon

J. Atm. Sol-Terr. Phys. 65 巻頁： 971-978 2003年

Field-aligned ion motions in the E-F transition region: 1. Mean characteristics 査読有り

Oyama, S., S. Nozawa, S. Maeda, Y. Murayama, R. Fujii, and H. Shinagawa

J. Geophys. Res. 108 巻頁： 10,1029/2003JA009830 2003年

High latitude mesospheric mean winds: a comparison between Troms? (69°N) and Svalbard (78°N) 査読有り

Hall, C. M., T. Aso, A.H. Manson, C.E. Meek, S. Nozawa, and M. Tsutsumi

J. Geophys. Res. 108 巻頁： 10.1029/2003JD003509 2003年

オーロラ領域における熱圏大気および電離圏ダイナミクス査読有り

品川裕之、大山伸一郎、野澤悟徳、ステファン　ブハート、藤井良一、石井守

31 巻頁： 951-956 2003年

*トロムソおよびポーカーフラットMFレーダーを用いた準2日波の研究査読有り

野澤悟徳、岩橋裕幸、アスゲイア　ブレッケ、クリス　ミーク、アラン　マンソン、大山伸一郎、村山泰啓、藤井良一

108 巻頁： 101029/2002JD003221 2003年

*北極域中間における準２日波の研究査読有り

野澤悟徳、今井田星子、アスゲイア　ブレッケ、クリス　ホール、クリス　ミーク、大山伸一郎、土橋一仁、藤井良一

108 巻頁： 10.1029/2002JD002440, ACL 3-1 - 3-12 2003年

On the response of upper homosphere turbulence to solar and geomagnetic disturbances 査読有り

Hall, C. M., S. Nozawa, C. E. Meek, and A. H. Manson

Earth Plannets Sci. 54 巻頁： 699-705 2002年

Field-aligned currents and ionospheric parameters deduced from EISCAT radar measurements in the post-midnight sector 査読有り

Sugino, M., R. Fujii, S. Nozawa, T. Nagatsuma, S. C. Buchert , J. W. Gjerloev, and M. J. Kosch

Ann. Geophysicae 20 巻頁： 1335-1348 2002年

On the factors controlling the power of F-region coherent echoes 査読有り

Danskin, D. W., A.V. Koustov, T. Ogawa, N. Nishitani, S. Nozawa, S. E. Milan, M. Lester, and D. Andre

Ann. Geophysicae 20 巻頁： 1385-1397 2002年

Ion and neutral temperature distributions in the dayside lower E-region observed by the EISCAT Troms? and Svalbard radars 査読有り

Maeda, S., S. Nozawa, M. Sugino, H. Fujiwara and M. Suzuki

Ann. Geophysicae 20 巻頁： 1415-1427 2002年

E領域およびF領域における磁力線方向のイオンの運動査読有り

藤井良一、大山伸一郎、ステファン　ブハート、野澤悟徳、松浦延夫

米国地球物理連合学会誌 107 巻頁： 10.129/2001JA900148 2002年

12MHzおよび144MHzでのオーロラ干渉エコーの速度査読有り

20 巻頁： 1647-1661 2002年

EISCAT UHFレーダーおよびトロムソMFレーダーから導出したオーロラ下部熱圏中性風の比較研究査読有り

野澤悟徳、アスゲイア　ブレッケ、アラン　マンソン、クリス　ホール、クリス　ミーク、森瀬和宏、大山伸一郎、土橋一仁、藤井良一

107 巻頁： 10.1029/2000JA007581, SIA 29-1 - SIA29-20 2002年

電離圏伝導度と電場の電離圏電流への寄与査読有り

米国地球物理連合学会誌 107 巻頁： 10.1029/2001JA007545, SIA20-1 - 20-15 2002年

乱流E領域における電子温度等方性査読有り

斎藤享、ステファン　ブハート、野澤悟徳、藤井良一

19 巻頁： 11-15 2001年

EISCAT VHFレーダーで観測された高緯度 Pi3 査読有り

長妻努、野澤悟徳、ステファン　ブハート、藤井良一

27 巻 ( 8 ) 頁： 1429-1431 2001年

オーロラF領域におけるオーロラアークの大気重力波励起効果査読有り

大山伸一郎、品川裕之、ステファン　ブハート、藤井良一、野澤悟徳、石井守、村山泰啓、ボルデック　コフマン

27 巻 ( 10 ) 頁： 1767-1772 2001年

EISCATとNCAR TIME-GCMによる下部熱圏風の比較研究査読有り

野澤　悟徳、ハンリー　リュウ、アート　リッチモンド、レイ　ローブル

米国地球物理連合学会誌 106 巻頁： 24,691-24,700 2001年

極域F領域におけるオーロラ活動に伴う大気重力波の励起査読有り

大山伸一郎、石井守、村山泰啓、品川裕之、野澤悟徳、ステファン　ブハート、藤井良一、ボルデック　コフマン

106 巻頁： 18543-18554 2001年

MF レーダーで観測した中性風速度を用いた乱流エネルギー散逸係数の決定査読有り

クリス　ホール、野澤悟徳、アラン　マンソン、クリス　ミーク

52 巻頁： 137-141 2000年

EISCAT スヴァルバールレーダーと VHF レーダーを用いた異なるアスペクト角からのイオン上昇流の観測査読有り

小川泰信、藤井良一、ステファン　ブハート、野澤悟徳、渡部重十、ファン　アイケン

米国地球物理連合学会誌・レター 27 巻頁： 81-84 2000年

ISスペクトラに対するカッパ分布した電子の影響査読有り

斎藤享、フランソワ　フォルム、ステファン　ブハート、野澤悟徳、藤井良一

18 巻頁： 1216-1223 2000年

EISCATレーダーとFPI干渉計を用いた電離圏・熱圏相互作用査読有り

25 巻頁： 563-566 2000年

極域F領域における沿磁力線方向イオン運動でみられる大気振動の効果査読有り

18 巻頁： 1154-1163 2000年

夏期地磁気静穏時におけるオーロラE領域中性風のケーススタディー査読有り

野澤悟徳、アスゲイア　ブレッケ

米国地球物理連合学会誌・電波科学 35 巻頁： 845-863 2000年

あけぼの衛星とEISCATレーダー同時観測データを用いた夜側逆V字型領域における超音速イオン上昇流査読有り

62 巻頁： 449-465 2000年

EISCAT VHFレーダーで観測した上部電離圏でのイオン上昇流および下降流査読有り

遠藤　実、藤井良一、小川泰信、ステファン　ブハート、野澤悟徳、渡部重十、吉田直文

18 巻頁： 170-181 2000年

磁気圏・電離圏・熱圏間におけるエネルギー相互作用査読有り

藤井良一、野澤悟徳、ステファン　ブハート、アスゲイア　ブレッケ

25 巻 ( 1 ) 頁： 213-218 2000年

FPI干渉計とEISCATレーダにより観測された熱圏風と温度の比較査読有り

26 巻 ( 6 ) 頁： 979-984 2000年

異なる太陽活動におけるE領域中性風の季節変化査読有り

野澤悟徳、アスゲイア　ブレッケ

61 巻頁： 585-605 1999年

１太陽周期期間におけるオーロラ帯E領域中性風の研究～地磁気静穏時～査読有り

野澤悟徳、アスゲイア　ブレッケ

104 巻頁： 45-66 1999年

２つのFPI干渉計による極域中性風ダイナミクス査読有り

石井守、大山伸一郎、野澤悟徳、藤井良一、瀬川、亘　慎一、品川裕之

51 巻頁： 833-844 1999年

磁気圏・電離圏・熱圏間における電磁気エネルギー輸送に関する統計研究査読有り

藤井良一、野澤悟徳、ステファン　ブハート、松浦延夫、アスゲイア　ブレッケ

米国地球物理連合学会誌 104 巻頁： 2357-2365 1999年

夏期地磁気静穏時の高緯度下部熱圏の昼間における中性風の研究査読有り

前田佐和子、藤原　均、野澤悟徳

米国地球物理連合学会誌 104 巻頁： 19,871-19,879 1999年

EISCAT CP-1 データを用いた極域電離圏における中性風の電磁気ダイナミクスに対する影響査読有り

藤井良一、野澤悟徳、松浦延夫、アスゲイア　ブレッケ

米国地球物理連合学会誌 103 巻頁： 14731-14739 1998年

極域方向に移動するF領域プラズマパッチ発生時の極冠域電離圏による昼間電磁波吸収査読有り

西野正徳、野澤悟徳、ヤン　ホルテット

50 巻頁： 107-117 1998年

オーロラ電離圏におけるイオン運動査読有り

藤井良一、野澤悟徳、ステファン　ブハート、松浦延夫、アスゲイア　ブレッケ

米国地球物理連合学会誌 103 巻頁： 20,685-20,695 1998年

2つのロングランデータに基づくE領域中性風の研究査読有り

野澤悟徳、アスゲイア　ブレッケ、藤井良一

49 巻頁： 641-673 1997年

地磁気擾乱時におけるE領域中性風の研究査読有り

野澤悟徳、アスゲイア　ブレッケ

米国地球物理連合学会誌 100 巻頁： 14,717-14,734 1995年

降下電子スペクトルの比較研究-EISCATとDMSPに基づく- 査読有り

藤井良一、野澤悟徳、佐藤真理子、松浦延夫、小野高幸、アスゲイア　ブレッケ、クリス　ホール、トルース　ハンセン

47 巻頁： 771-782 1995年

輝いプロトステラーオブジェクを伴う2つの小分子雲の¹²COと¹³CO輝線を用いた観測査読有り

日本天文学会誌・レター 47 巻頁： 837-843 1995年

EISCATレーダーで観測されるE領域の諸物理量について査読有り

アスゲイア　ブレッケ、野澤悟徳、佐藤真理子

47 巻頁： 889-909 1995年

極域電離圏における電揚と電流の局所的見積り査読有り

佐藤真理子、上出洋介、アート　リッチモンド、アスゲイア　ブレッケ、野澤悟徳

米国地球物理連合会レター誌 22 巻頁： 283-286 1995年

IRAS22134+5834に伴う分子雲とCO分子流（共著）査読有り

土橋一仁、野澤悟徳、林、佐藤文男、福井康雄

米国天文学会誌 107 巻頁： 2148-2152 1994年

地磁気静穏時におけるE領域中性風の研究（共著）査読有り

アスゲイア　ブレッケ、野澤悟徳、トリグブ　スパー

米国地球物理連合学会誌 99 巻頁： 8801-8825 1994年

名古屋大学４m電波望遠鏡によるオゾン混合比の観測査読有り

44 巻頁： 1085-1096 1992年

へびつかい座における ¹³CO　分子雲コアの研究査読有り

野澤悟徳、水野亮、手嶋芳徳、小川英夫、福井康雄

米国天文学会誌・サプリメント 77 巻頁： 647-675 1991年

p Oph ストリーマーに添う速度構造の分離－大質量星生成領域における角運動量の放出査読有り

42 巻頁： 69-83 1990年

IRAS 16293-2422に附随した p Oph-Eastの顕著な分子流査読有り

水野亮、福井康雄、岩田隆浩、野澤悟徳、鷹野敏明

米国天文学会誌 356 巻頁： 184-194 1990年

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