Updated on 2024/04/01

写真a

 
SHINBORI Atsuki
 
Organization
Institute for Space-Earth Environmental Research Center for Integrated Data Science Designated assistant professor
Title
Designated assistant professor
External link

Degree 1

  1. Doctor (Science) ( 2006.3   Tohoku University ) 

Research Interests 4

  1. Plasmasphere

  2. Geomagnetic storm

  3. Ionosphere

  4. Total Electron Content (TEC)

Research Areas 3

  1. Natural Science / Space and planetary sciences  / 電離圏

  2. Natural Science / Space and planetary sciences

  3. Natural Science / Space and planetary sciences

Current Research Project and SDGs 3

  1. A study on temporal and spatial variations in the ionosphere and plasmasphere based on the global TEC data analysis

  2. 地震・火山噴火に伴う電離圏擾乱の解明

  3. 地上―衛星観測と物理モデルを組み合わせた磁気嵐時の電離圏ー熱圏結合過程の解明

Research History 7

  1. Institute for Space-Earth Environmental Research, Nagoya University   Division for Ionospheric and Magnetospheric Research   Designated assistant professor

    2017.4

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    Country:Japan

  2. Institute for Space-Earth Environmental Research, Nagoya University   Division for Ionospheric and Magnetospheric Research   Researcher

    2016.11 - 2017.3

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    Country:Japan

  3. Research Institute for Sustainable Humanosphere, Kyoto University   Center for Exploratory Research on the Humanosphere   Exploratory Research by Mission Research Fellows

    2015.4 - 2016.10

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    Country:Japan

  4. Research Institute for Sustainable Humanosphere (RISH), Kyoto University   Laboratory of Atmospheric Sensing and Diagnosis   Researcher

    2010.4 - 2015.3

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    Country:Japan

  5. Solar-Terrestrial Environment Laboratory, Nagoya University   Division for Integrated Studies   Researcher

    2009.5 - 2010.3

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    Country:Japan

  6. Solar-Terrestrial Environment Laboratory, Nagoya University   Division for Integrated Studies   Researcher

    2009.4

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    Country:Japan

  7. Solar-Terrestrial Environment Laboratory, Nagoya University   Division for Integrated Studies   JSPS Research Fellowship for Young Scientists (PD)

    2006.4 - 2009.3

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    Country:Japan

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Education 4

  1. Tohoku University   Graduate School, Division of Natural Science

    - 2006.3

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    Country: Japan

  2. Tohoku University   Graduate School of Science   Department of Geophysics

    2003.4 - 2006.3

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    Country: Japan

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  3. Tohoku University   Graduate School of Science   Department of Geophysics

    2001.4 - 2003.3

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    Country: Japan

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  4. Tohoku University   Faculty of Science   Graduate school of Geophysics

    1997.4 - 2001.3

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    Country: Japan

Professional Memberships 4

  1. The Institute of Positioning, Navigation, and Timing of Japan

    2022.1

  2. Japan Geoscience Union

    2006.1

  3. American Geophysical Union

    2003.11

  4. Society of Geomagnetism and Earth, Planetary and Space Sciences

    2002.1

Awards 8

  1. EPS Highlighted Papers 2023

    2024.2   Earth, Planets and Space   New aspects of the upper atmospheric disturbances caused by the explosive eruption of the 2022 Hunga Tonga–Hunga Ha’apai volcano

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    Award type:Honored in official journal of a scientific society, scientific journal  Country:Japan

  2. Excellent Reviewers 2023

    2024.2   Earth, Planets and Space  

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    Country:Japan

  3. SGEPSS Outstanding Paper Award

    2023.9   Society of Geomagnetism and Earth, Planetary and Space Sciences   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 observation

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

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    Award type:Award from Japanese society, conference, symposium, etc.  Country:Japan

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  4. Highlighted Papers 2022

    2023.2   Earth, Planets and Space   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

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  5. SGEPSS Student Presentation Award (Aurora Medal)

    2006.5   Society of Geomagnetism and Earth, Planetary and Space Sciences  

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  6. 青葉理学振興会賞

    2006.3   東北大学大学院理学研究科青葉理学振興会  

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  7. 優秀ポスター賞

    2004.3   北方圏環境変動研究計画に関する国際レビュー会議  

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  8. 東北大学青葉理学振興会奨励賞

    2000.3   東北大学青葉理学振興会  

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    Award type:Award from publisher, newspaper, foundation, etc.  Country:Japan

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Papers 138

  1. Thermospheric Wind Response to March 2023 Storm: Largest Wind Ever Observed With a Fabry-Perot Interferometer in Tromsø, Norway Since 2009 Reviewed

    Oyama, S; Vanhamäki, H; Cai, L; Shinbori, A; Hosokawa, K; Sakanoi, T; Shiokawa, K; Aikio, A; Virtanen, II; Ogawa, Y; Miyoshi, Y; Kurita, S; Nishitani, N

    SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS   Vol. 22 ( 3 )   2024.3

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Space Weather  

    Solar cycles 24–25 were quiet until a geomagnetic storm with a Sym-H index of −170 nT occurred in late March 2023. On March 23–24, a Fabry-Perot interferometer (FPI; 630 nm) in Tromsø, Norway, recorded the highest thermospheric wind speed of over 500 m/s since 2009. Comparisons with magnetometer readings in Scandinavia showed that a large amount of electromagnetic energy was transferred to the ionosphere-thermosphere system. Total electron content maps suggested an enlarged auroral oval and revealed that the FPI observed winds near the polar cap instead of inside the oval for a long period during the storm main phase. The FPI wind had a strong equatorward component during the storm, likely because of the powerful anti-sunward ionospheric plasma flow in the polar cap. The positive Y-component of the IMF for 6 days before the storm caused a successive westward component of the FPI-measured wind during the storm main phase. On March 24, the first day of the storm recovery phase, thermospheric wind disturbed and the ionospheric density decreased significantly at high latitudes. This density depression lasted for several days, and a large amount of electromagnetic energy during the storm modified the thermospheric dynamics and ionospheric plasma density.

    DOI: 10.1029/2023SW003728

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  2. Performance of the double-thin-shell approach for studying nighttime medium-scale traveling ionospheric disturbances using two dense GNSS observation networks in Japan Reviewed

    Fu, WZ; Otsuka, Y; Shinbori, A; Nishioka, M; Perwitasari, S

    EARTH PLANETS AND SPACE   Vol. 76 ( 1 )   2024.1

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Earth, Planets and Space  

    Electrodynamic coupling between the ionospheric E and F regions is widely recognized as the underlying mechanism for generating medium-scale traveling ionospheric disturbances (MSTIDs) during nighttime at midlatitudes. Recently, the double-thin-shell approach has proven to be a useful tool for studying the E–F coupling. By using total electron content (TEC) measurements, this approach enables the simultaneous reconstruction of electron density perturbations in both the E and F regions with broad and continuous coverage. However, the current reconstruction performance is limited when using only GPS-TEC measurements from GEONET, a dense network of ground-based Global Navigation Satellite System (GNSS) receivers over Japan. The expansion of available data sources and the integration of multi-GNSS observation data are considered important to enhance the double-thin-shell model. Fortunately, SoftBank Corp., a Japanese telecommunications provider, has recently developed a dense independent GNSS observation network to improve positioning services. In this paper, we analyze the potential of the improved double-thin-shell approach and emphasize the importance of incorporating multi-GNSS observation data from both GEONET and SoftBank networks. The solvability analysis, simulation, and observation results collectively indicate a substantial improvement in the spatiotemporal resolution. Specifically, the longitudinal and latitudinal resolution is improved from 0.15° to 0.1° in the E region, and from 0.5° to 0.3° in the F region. The temporal resolution is also improved from 2 to 1 min. In addition, significant improvements have been achieved in the reconstruction performance, particularly for the E region under complex background conditions. Based on these assessments, we conclude that the incorporation of GEONET and SoftBank GNSS observation data holds significant potential for improving the double-thin-shell model and advancing our understanding of MSTIDs. Graphical abstract: [Figure not available: see fulltext.]

    DOI: 10.1186/s40623-023-01956-8

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  3. Statistical Analysis of Global and Regional Ionospheric Total Electron Content (TEC) Using Extreme Value Distributions Reviewed

    Emmela, S; Ratnam, DV; Otsuka, Y; Shinbori, A; Sori, T; Nishioka, M; Perwitasari, S

    IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING   Vol. 62   page: 1 - 8   2024

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IEEE Transactions on Geoscience and Remote Sensing  

    Satellite-based radio communication and navigation systems rely mostly on transionospheric propagation of radio signals concerning changes by total electron content (TEC). Therefore, it is necessary to understand the changing behavior of structural variations of ionospheric TEC for high-frequency applications besides mitigating the risks associated with the space weather impacts for navigation and aviation applications. The reference thresholds identified for moderate and severe levels of threshold activity for TEC by the International Civil Aviation Organization (ICAO) are 125 and 175 TECU, respectively. In view of this, statistical analysis of long-term ground-based global navigation satellite system (GNSS) TEC data of 25 years (1997-2021) using extreme value theory (EVT) is performed for both magnetically quiet and disturbed day conditions for four different regions - India (5-45°N), Japan low (20-30°N), Japan mid-latitudes (30-50°N), and global regions to identify the extreme ionospheric TEC events that take place once in 11, 22, 44, 66, 88, and 110 years with 95% confidence intervals. In the present work, both generalized extreme value (GEV) using annual maxima and generalized Pareto distribution (GPD) using peak-over-threshold (PoT) analysis are performed. A likelihood test and PoT constraint in addition to adjustment of shape parameter illustrate that GPD works better than GEV to identify return periods of extreme events. The recommended TEC moderate and severe thresholds for India, Japan low, Japan mid-latitude, and global regions are 121, 101, 90, and 139 TECU and 131, 135, 98, and 157 TECU, respectively. The analysis would be helpful in developing risk assessment and mitigation strategies for critical (GNSS) space weather systems.

    DOI: 10.1109/TGRS.2023.3338513

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  4. Multi-Instrument Observations of the Evolution of Polar Cap Patches Associated With Flow Shears and Particle Precipitation Reviewed

    Zhang, D; Zhang, QH; Oksavik, K; Xing, ZY; Lyons, LR; Yang, HG; Li, GJ; Hosokawa, K; Shinbori, A; Ma, YZ; Wang, Y; Wang, XY

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 128 ( 12 )   2023.12

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    Simultaneous observations from Defense Meteorological Satellite Program, Swarm, Resolute Bay all-sky imagers, GPS Total Electron Content and Super Dual Auroral Radar Network, are used to investigate the evolution and key characteristics of the Tongue of Ionization (TOI) being restructured into a polar cap patch. Six satellites crossed the TOI of patch as it moved from the dayside to the nightside. It was initially hot, then a mix of both cold and hot, and finally it became a cold patch. This suggests that cold patch is not only a result of solar extreme ultraviolet radiation, but may also develop when a hot patch cools down. Soft-electron precipitation and flow shears both contribute to the TOI restructuring and the appearance of polar cap patch. The plasma density of patch at ∼500 km was at least 4 times higher than at ∼800 km. The plasma density enhancement gradually decreased as the patch evolved due to decreased production and transport of cold nightside low-density plasma. Moreover, the duskward motion of the patch was influenced by changes in the ionospheric convection pattern.

    DOI: 10.1029/2023JA032176

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  5. New aspects of the upper atmospheric disturbances caused by the explosive eruption of the 2022 Hunga Tonga–Hunga Ha’apai volcano Invited Reviewed

    A. Shinbori, Y. Otsuka, T. Sori, M. Nishioka, S. Perwitasari, T. T. Tsuda, N. Nishitani, A. Kumamoto, F. Tsuchiya, S. Matsuda, Y. Kasahara, A. Matsuoka, S. Nakamura, Y. Miyoshi, I. Shinohara

    Earth Planets Space   Vol. 75 ( 1 ) page: 175   2023.11

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    DOI: 10.1186/s40623-023-01930-4

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  6. Spatio-Temporal Characteristics of IPDP-Type EMIC Waves on April 19, 2017: Implications for Loss of Relativistic Electrons in the Outer Belt Reviewed

    Asuka Hirai, Fuminori Tsuchiya, Takahiro Obara, Yuto Katoh, Yoshizumi Miyoshi, Kazuo Shiokawa, Yasumasa Kasaba, Hiroaki Misawa, Chae Woo Jun, Satoshi Kurita, Martin G. Connors, Aaron T. Hendry, Atsuki Shinbori, Yuichi Otsuka, Takuya Tsugawa, Michi Nishioka, Septi Perwitasari, Jerry W. Manweiler

    Journal of Geophysical Research: Space Physics   Vol. 128 ( 8 )   2023.8

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    To understand the mechanism of the increased frequency of intervals of pulsations of diminishing periods (IPDPs), we analyzed IPDP-type electromagnetic ion cyclotron (EMIC) waves that occurred on 19 April 2017, using ground and satellite observations. Observations by low-altitude satellites and ground-based magnetometers indicate that the increased IPDP frequency is caused by an inward (i.e., Earthward) shift of the EMIC wave source region. The EMIC wave source region moves inward along the mid-latitude trough, which we used as a proxy for the plasmapause location. A statistical analysis shows that increases in the IPDP frequency showed a positive correlation with polar cap potentials. These results suggest an enhanced convection electric field causes an inward shift of the source region. The inward shift of the source region allows EMIC waves to scatter relativistic electrons over a wide range of radial distances during the IPDP event. This mechanism suggests that IPDP-type EMIC waves are more likely to scatter relativistic electrons than other EMIC waves. We also show that the decreased phase-space density of relativistic electrons in the outer radiation belt is consistent with the extent of the source region and the resonant energy of EMIC waves, implying a possible contribution of EMIC waves to outer radiation belt loss during the main phase of geomagnetic storms.

    DOI: 10.1029/2023JA031479

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  7. IMF Dependence of Midnight Bifurcation in the Thermospheric Wind at an Auroral Latitude Based on Nine Winter Measurements in Tromsø, Norway Reviewed

    S. Oyama, K. Hosokawa, H. Vanhamäki, A. Aikio, T. Sakanoi, L. Cai, I. I. Virtanen, K. Shiokawa, N. Nishitani, A. Shinbori, Y. Ogawa

    Geophysical Research Letters   Vol. 50 ( 14 )   2023.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Geophysical Union (AGU)  

    DOI: 10.1029/2023GL104334

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  8. Generation of equatorial plasma bubble after the 2022 Tonga volcanic eruption Reviewed

    A. Shinbori, T. Sori, Y. Otsuka, M. Nishioka, S. Perwitasari, T. T. Tsuda, A. Kumamoto, F. Tsuchiya, S. Matsuda, Y. Kasahara, A. Matsuoka, S. Nakamura, Y. Miyoshi, I. Shinohara

    Sci. Rep.   Vol. 13 ( 1 ) page: 6450   2023.5

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    DOI: 10.1038/s41598-023-33603-3

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  9. Generation of equatorial plasma bubble after the 2022 Tonga volcanic eruption Reviewed

    Shinbori Atsuki, Sori Takuya, Otsuka Yuichi, Nishioka Michi, Perwitasari Septi, Tsuda Takuo, Kumamoto Atsushi, Tsuchiya Fuminori, Matsuda Shoya, Kasahara Yoshiya, Matsuoka Ayako, Nakamura Satoko, Miyoshi Yoshizumi, Shinohara Iku

    Scientific Reports   Vol. 13   2023.5

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    Equatorial plasma bubbles are a phenomenon of plasma density depletion with small-scale density irregularities, normally observed in the equatorial ionosphere. This phenomenon, which impacts satellite-based communications, was observed in the Asia-Pacific region after the largest-on-record January 15, 2022 eruption of the Tonga volcano. We used satellite and ground-based ionospheric observations to demonstrate that an air pressure wave triggered by the Tonga volcanic eruption could cause the emergence of an equatorial plasma bubble. The most prominent observation result shows a sudden increase of electron density and height of the ionosphere several ten minutes to hours before the initial arrival of the air pressure wave in the lower atmosphere. The propagation speed of ionospheric electron density variations was ~ 480–540 m/s, whose speed was higher than that of a Lamb wave (~315 m/s) in the troposphere. The electron density variations started larger in the Northern Hemisphere than in the Southern Hemisphere. The fast response of the ionosphere could be caused by an instantaneous transmission of the electric field to the magnetic conjugate ionosphere along the magnetic field lines. After the ionospheric perturbations, electron density depletion appeared in the equatorial and low-latitude ionosphere and extended at least up to ±25° in geomagnetic latitude.

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  10. Geomagnetic activity dependence and dawn-dusk asymmetry of thermospheric winds from 9-year measurements with a Fabry–Perot interferometer in Tromsø, Norway Reviewed

    Shin ichiro Oyama, Anita Aikio, Takeshi Sakanoi, Keisuke Hosokawa, Heikki Vanhamäki, Lei Cai, Ilkka Virtanen, Marcus Pedersen, Kazuo Shiokawa, Atsuki Shinbori, Nozomu Nishitani, Yasunobu Ogawa

    Earth, Planets and Space   Vol. 75 ( 1 )   2023.5

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    Ion drag associated with the ionospheric plasma convection plays an important role in the high-latitude thermospheric dynamics, yet changes in the thermospheric wind with geomagnetic activity are not fully understood. We performed a statistical analysis of the thermospheric wind measurements with a Fabry–Perot interferometer (FPI; 630 nm wavelength) in Tromsø, Norway, in the winter months for 9 years. The measurements were sorted by a SuperMAG (SME) index, and a quiet-time wind pattern was defined as an hourly mean under SME ≤ 40 nT. The quiet-time wind pattern can be expected to be represented by a pressure gradient associated with the solar radiation and a geostrophic force balance. With an increase in the geomagnetic activity level, the thermospheric wind turned over from eastward to westward at dusk and increased the equatorward magnitude from midnight to dawn. Deviations from the quiet-time wind presented similar patterns in the direction with the ionospheric plasma convection but were larger in magnitude at dusk than at dawn. This is the first study to report a dawn-dusk asymmetry of the thermospheric wind acceleration feature and signatures of the eastward wind acceleration at dawn by ion drag. Graphical Abstract: [Figure not available: see fulltext.].

    DOI: 10.1186/s40623-023-01829-0

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  11. First Detection of Midlatitude Plasma Bubble by SuperDARN During a Geomagnetic Storm on May 27 and 28, 2017 Reviewed

    Sori, T; Shinbori, A; Otsuka, Y; Nishioka, M; Perwitasari, S; Nishitani, N

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 128 ( 4 )   2023.4

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Journal of Geophysical Research: Space Physics  

    We used the global navigation satellite system-total electron content (TEC) and Super Dual Auroral Radar Network (SuperDARN) radar to elucidate the characteristics of the plasma bubble extending to midlatitudes over North America during a geomagnetic storm on 27 and 28 May 2017. To identify plasma bubbles, we analyzed the rate of the TEC index (ROTI), which is a good indicator of the occurrence of plasma bubbles. The enhanced ROTI region expanded up to 50°N (geomagnetic latitude), and the upper limit of this region coincided with the equatorward wall of the midlatitude trough. Two-dimensional ROTI maps show that the enhanced midlatitude ROTI region moved westward at a bulk speed of approximately 310 m/s. The Fort Hays East SuperDARN radar also detected the radar echo, showing the existence of plasma density irregularities at ∼10-m scales within the midlatitude plasma bubble. The radar echo had a westward velocity of ∼300 m/s, which is almost consistent with the westward motion of the enhanced midlatitude ROTI region. We deduced that the westward propagation of the plasma bubble could be caused by a poleward sub-auroral polarization stream electric field. The observed radar echo overlapping with the enhanced ROTI region had a narrower spectral width (<50 m/s) than that of the auroral activity. This feature resembled that of the type 1 echo, although the Doppler velocity was smaller than the ion acoustic speed at the F-region height. This is the first case in which plasma density irregularities within plasma bubbles were captured by the SuperDARN radar.

    DOI: 10.1029/2022JA031157

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  12. Statistical analysis for EUV dynamic spectra and their impact on the ionosphere during solar flares Reviewed International journal

    Shohei Nishimoto, Kyoko Watanabe, Hidekatsu Jin, Toshiki Kawai, Shinsuke Imada, Tomoko Kawate, Yuichi Otsuka, Atsuki Shinbori, Takuya Tsugawa, Michi Nishioka

    Earth, Planets and Space   Vol. 75 ( 1 )   2023.3

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

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    The X-rays and extreme ultraviolet (EUV) emitted during solar flares can rapidly change the physical composition of Earth’s ionosphere, causing space weather phenomena. It is important to develop an accurate understanding of solar flare emission spectra to understand how it affects the ionosphere. We reproduced the entire solar flare emission spectrum using an empirical model and physics-based model, and input it into the Earth’s atmospheric model, GAIA to calculate the total electron content (TEC) enhancement due to solar flare emission. We compared the statistics of nine solar flare events and calculated the TEC enhancements with the corresponding observed data. The model used in this study was able to estimate the TEC enhancement due to solar flare emission with a correlation coefficient greater than 0.9. The results of this study indicate that the TEC enhancement due to solar flare emission is determined by soft X-ray and EUV emission with wavelengths shorter than 35 nm. The TEC enhancement is found to be largely due to the change in the soft X-ray emission and EUV line emissions with wavelengths, such as Fe XVII 10.08 nm, Fe XIX 10.85 nm and He II 30.38 nm.

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    DOI: 10.1186/s40623-023-01788-6

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  13. Dependence of Ionospheric Responses on Solar Wind Dynamic Pressure During Geomagnetic Storms Using Global Long-Term GNSS-TEC Data Reviewed

    Sori, T; Shinbori, A; Otsuka, Y; Nishioka, M; Perwitasari, S

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 128 ( 3 )   2023.3

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Journal of Geophysical Research: Space Physics  

    To elucidate the effect of solar wind dynamic pressure on the activities of ionospheric plasma irregularities in both high-latitude and equatorial regions, we analyzed the long-term global navigation satellite system (GNSS) total electron content (TEC) data from 2000 to 2018 and performed a superposed epoch analysis of the GNSS rate of the TEC index (ROTI), solar wind, interplanetary magnetic field (IMF), and geomagnetic index. We found that during the main phase of geomagnetic storms, the activities of ionospheric plasma irregularities were considerably enhanced in both high-latitude and equatorial regions under high-pressure conditions, and the equatorward edge of the auroral oval moved to lower latitudes. The poleward edge of the enhanced low-latitude ROTI region (occurrence region of the plasma bubbles) in the evening sector extended to higher latitudes under high-pressure conditions. During the recovery phase of geomagnetic storms, the plasma bubble occurrence in the dusk sector was suppressed under high-pressure conditions. Our results suggest that the high-latitude convection electric field and the penetration and disturbance dynamo electric fields at low latitudes become stronger during geomagnetic storms when the solar wind dynamic pressure is enhanced. This is because the conversion from solar wind energy to electromagnetic energy in the magnetosphere is enhanced by the formation of a high plasma pressure area in the high-latitude cusp and mantle region. Therefore, not only the southward IMF but also solar wind dynamic pressure are important factors for varying global ionospheric responses during geomagnetic storms.

    DOI: 10.1029/2022JA030913

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  14. Multi-Event Analysis of Magnetosphere-Ionosphere Coupling of Nighttime Medium-Scale Traveling Ionospheric Disturbances From the Ground and the Arase Satellite Reviewed

    K. Kawai, K. Shiokawa, Y. Otsuka, S. Oyama, M. G. Connors, Y. Kasahara, Y. Kasaba, S. Nakamura, F. Tsuchiya, A. Kumamoto, A. Shinbori, A. Matsuoka, I. Shinohara, Y. Miyoshi

    Journal of Geophysical Research: Space Physics   Vol. 128 ( 2 )   2023.2

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    Kawai et al. (2021) reported the first ground-satellite conjugate observation of nighttime medium-scale traveling ionospheric disturbances (MSTIDs), by analyzing measurements from an airglow imager at Gakona (geographic latitude: 62.39°N, geographic longitude: 214.78°E, magnetic latitude: 63.60°N) and the Arase satellite in the magnetosphere on 3 November 2018. The Arase satellite observed variations in both the polarization electric field and the electron density as the Arase footprint passed through the MSTID structures in the ionosphere. In this study, we investigated whether these electric field and density variations associated with MSTIDs at subauroral latitudes are always observed by Arase in the magnetosphere. We used three airglow imagers installed at Gakona, Athabasca (geographic latitude: 54.60°N, geographic longitude: 246.36°E, magnetic latitude: 61.10°N), and Kapuskasing (geographic latitude: 49.39°N, geographic longitude: 277.81°E, magnetic latitude: 58.70°N) and the Arase satellite. We found eight observations of MSTIDs conjugate with Arase. They indicate that electric field and density variations associated with MSTIDs are not always observed in the magnetosphere. These variations tend to be observed in the magnetosphere during geomagnetically quiet times and when the amplitude of the MSTID is large. We categorized the MSTIDs into those caused by plasma instabilities and gravity waves and found that the electric field and density variations can be observed in the magnetosphere for both types of MSTIDs.

    DOI: 10.1029/2022JA030542

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  15. Advanced tools for guiding data‐led research processes of Upper‐Atmospheric phenomena Reviewed

    Yoshimasa Tanaka, Norio Umemura, Shuji Abe, Atsuki Shinbori, Satoru UeNo

    Geoscience Data Journal   Vol. 10 ( 1 ) page: 130 - 141   2023.1

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    DOI: 10.1002/gdj3.170

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    Other Link: https://onlinelibrary.wiley.com/doi/full-xml/10.1002/gdj3.170

  16. Advanced tools for guiding data‐led research processes of Upper‐Atmospheric phenomena Reviewed

    Tanaka Yoshimasa, Umemura Norio, Abe Shuji, Shinbori Atsuki, UeNo Satoru

    Geoscience Data Journal   Vol. 10 ( 1 ) page: 130 - 141   2023.1

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    This paper presents tools that help researchers implement the processes of data-led studies of upper-atmospheric phenomena. These tools were developed as a part of the activities of the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) of Japan, which is a project to develop infrastructure for upper-atmospheric research data. This paper focuses on the data service named IUGONET Type-A, which was launched in October 2016 and has since evolved. In addition to being a conventional metadata catalogue, it has many other useful functions: an easy cross-searching system, a quick-look data-plotting procedure, an interactive data visualization system named UDAS web, and strong linkage with analysis software. Users can pick up relevant data from a huge number of data sets using either lists categorized by instruments/projects, observed regions and special campaigns or a world map of observatories. Users can quickly find the time, location and nature of phenomena that occurred by comparing the quick-look plots of various data displayed by the browser. UDAS web allows researchers to interactively create stacked plots of various data types that can facilitate the understanding of the relationships among phenomena observed in different regions. Furthermore, it presents a command list for software dedicated to data analysis that can smoothly lead users to perform detailed analyses. IUGONET Type-A provides a one-stop data service that can assist users in searching, examining and comprehending data for advanced analysis. It is also capable of handling old data, including analogue data and written paper documents. Thus, it will provide useful support for innovative interdisciplinary scientific research on solar–terrestrial phenomena.

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  17. An Extreme Value Analysis of Long-Term GNSS Ionospheric Total Electron Content Data Observed at Japan Grid Point Location (34.95° N and 134.05° E) Reviewed

    Emmela, S; Ratnam, DV; Otsuka, Y; Shinbori, A; Sori, T; Nishioka, M; Perwitasari, S

    IEEE GEOSCIENCE AND REMOTE SENSING LETTERS   Vol. 20   2023

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    Space weather adversely affects satellite systems by obstructing the services of global positioning systems (GPSs), delaying the launch of space vehicles, and causing damage to basic infrastructures such as radio-communications and power distribution networks. The spatio-temporal variations of ionospheric total electron content (TEC) during geomagnetic storms can be well examined by extreme value analysis. Statistical assessment and analysis of extreme values are necessary for developing risk assessment and mitigation strategies to the affected communication systems. In this study, extreme TEC events are investigated using 25 years (1997-2021) of long-term Global Navigation Satellite System (GNSS) Earth Observation Network System (GEONET) TEC data over Japan grid point location at 34.95° N and 134.05° E, and global data. In this work, a generalized extreme value (GEV) distribution is applied to the annual maxima TEC to evaluate geomagnetic disturbances that could occur once in 44, 88, 132, and 176 years with a confidence interval of 95%. According to the reference thresholds indicated by International Civil Aviation Organization (ICAO) for safer aviation applications, the moderate and severe levels of threshold for TEC are identified as 125 and 175 TEC Units (TECU), respectively. The results illustrate that the estimated extreme TECs for one in 44, 88, 132, and 176 years are 119, 125, 128, 130 and 215, 220, 222, 225 TECU for grid point and global TEC data respectively. That is, a moderate threshold level of activity is likely to happen over considered grid point for a return period of beyond 88 years and severe threshold level of activity beyond 11 years for global TEC data.

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  18. Oscillations of the Ionosphere Caused by the 2022 Tonga Volcanic Eruption Observed With SuperDARN Radars Reviewed

    Zhang, JJ; Xu, JY; Wang, W; Wang, GJ; Ruohoniemi, JM; Shinbori, A; Nishitani, N; Wang, C; Deng, X; Lan, AL; Yan, JY

    GEOPHYSICAL RESEARCH LETTERS   Vol. 49 ( 20 )   2022.10

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    On 15 January 2022, the submarine volcano on the southwest Pacific island of Tonga violently erupted. Thus far, the ionospheric oscillation features caused by the volcanic eruption have not been identified. Here, observations from the Super Dual Auroral Radar Network radars and digisondes were employed to analyze ionospheric oscillations in the Northern Hemisphere caused by the volcanic eruption in Tonga. Due to the magnetic field conjugate effect, the ionospheric oscillations were observed much earlier than the arrival of surface air pressure waves, and the maximum negative line-of-sight (LOS) velocity of the ionospheric oscillations exceeded 100 m/s in the F layer. After the surface air pressure waves arrived, the maximum LOS velocity in the E layer approached 150 m/s. A maximum upward displacement of 100 km was observed in the ionosphere. This work provides a new perspective for understanding the strong ionospheric oscillation caused by geological hazards observed on Earth.

    DOI: 10.1029/2022GL100555

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  19. Thermospheric wind response to a sudden ionospheric variation in the trough: Event at a pseudo breakup during geomagnetically quiet conditions Reviewed

    S.-i. Oyama, H. Vanhamäki, L. Cai, A. Aikio, M. Rietveld, Y. Ogawa, T. Raita, M. Kellinsalmi, K. Kauristie, B. Kozelov, A. Shinbori, K. Shiokawa, T. T. Tsuda, T. Sakanoi

    Earth Planets Space   Vol. 74 ( 1 ) page: 154   2022.10

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    The thermospheric wind response to a sudden westward turning of the ion velocity at a high latitude was studied by analyzing data obtained with a Fabry-Perot interferometer (FPI; 630 nm), Dynasonde, and Swarm A & C satellites during a conjunction event. The event occurred during a geomagnetically quiet period (Kp= 0+) through the night, but some auroral activity occurred in the north. The collocated FPI and Dynasonde measured the thermospheric wind (U) and ionospheric plasma velocity (V), respectively, in the F region at the equatorward trough edge. A notable scientific message from this study is the possible role of thermospheric wind in the energy dissipation process at F-region altitude. The FPI thermospheric wind did not instantly follow a sudden V change due to thermospheric inertia in the F region. At a pseudo-breakup during the event, V suddenly changed direction from eastward to westward within 10 min. U was concurrently accelerated westward, but its development was more gradual than that of V, with U remaining eastward for a while after the pseudo-breakup. The delay of U is attributed to the thermospheric inertia. During this transition interval, U.V was negative, which would result in more efficient generation of frictional heating than the positive U.V case. The sign of U.V, which is related to the relative directions of the neutral wind and plasma drift, is important because of its direct impact on ion-neutral energy exchange during collisions. This becomes especially important during substorm events, where rapid plasma velocity changes are common. The sign of U.V may be used as an indicator to find the times and locations where thermospheric inertia plays a role in the energy dissipation process.

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  20. Geomagnetic conjugacy of plasma bubbles extending to mid-latitudes during a geomagnetic storm on March 1, 2013 Reviewed

    Sori, T; Otsuka, Y; Shinbori, A; Nishioka, M; Perwitasari, S

    EARTH PLANETS AND SPACE   Vol. 74 ( 1 )   2022.8

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    This study, for the first time, reports the geomagnetically conjugate structure of a plasma bubble extending to the mid-latitudes and the asymmetrical structure of the decay of the plasma bubble during a geomagnetic storm. We investigated the temporal and spatial variations of plasma bubbles in the Asian sector during a geomagnetic storm on March 1, 2013, using Global Navigation Satellite System-total electron content data with high spatiotemporal resolutions. The first important point of our data analysis results is that the plasma bubble extended from the equator to the mid-latitudes with geomagnetic conjugacy along the magnetic field lines. The total electron content data showed that the plasma bubbles appeared in the equatorial regions near 150° E after sunset during the main phase of the geomagnetic storm. From ionosonde data over both Japan and Australia, they suggest that a large eastward electric field existed in the Asian sector. Finally, the plasma bubbles extended up to the mid-latitudes (~ 43° geomagnetic latitude) in both hemispheres, maintaining geomagnetic conjugacy. The second point is that the mid-latitude plasma bubble disappeared 1–2 h earlier in the northern hemisphere than in the southern hemisphere at close to midnight. In the northern hemisphere, the ionospheric virtual height decreased near midnight, followed by a rapid decrease in the total electron content and a rapid increase in the ionospheric virtual height. These results imply that the mid-latitude plasma bubble disappeared as the background plasma density decreased after midnight due to the recombination resulting from the descent of the F layer. Therefore, we can conclude that mid-latitude plasma bubbles can be asymmetric between the northern and southern hemispheres because of the rapid decay of plasma bubbles in one of the hemispheres. Graphical Abstract: [Figure not available: see fulltext.]

    DOI: 10.1186/s40623-022-01682-7

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  21. 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 Reviewed

    A. Shinbori, Y. Otsuka, T. Sori, M. Nishioka, S. Perwitasari, T. T. Tsuda, N. Nishitani

    Earth Planets Space   Vol. 74 ( 1 ) page: 106   2022.7

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  22. A confirmation of vertical acoustic resonance and field-aligned current generation just after the 2022 Hunga Tonga Hunga Ha'apai volcanic eruption Reviewed

    Iyemori, T; Nishioka, M; Otsuka, Y; Shinbori, A

    EARTH PLANETS AND SPACE   Vol. 74 ( 1 )   2022.6

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    A strong volcanic eruption caused a clear vertical acoustic resonance between the sea surface and the thermosphere. Its effects are observed as geomagnetic and GPS-TEC oscillations near the volcano and its geomagnetic conjugate area. The geomagnetic oscillations are observed at Apia and Honolulu geomagnetic observatories with amplitude of about 2 nT and 0.2 nT, respectively. The volcanic eruption started around 04:14 UT on January 15, 2022. The oscillations appeared at 04:21UT at Apia, Samoa, only about 7 min after the start of eruption. Because the distance between the volcano and Apia is about 841 km, it takes about 40 min for a sound wave to propagate from the volcano to Apia. Therefore, it is more plausible to assume that the magnetic oscillation observed at Apia about 7 min after the eruption is caused by the sound waves propagated vertically upward to the ionosphere and generated an electric current. The coherent appearance of geomagnetic oscillation at Honolulu located near the geomagnetic conjugate point of the volcano strongly support the idea that the ionospheric current generated over the volcano diverted as a field-aligned current which flew to the opposite hemisphere and caused the geomagnetic oscillation at Honolulu. The earliest start of GPS-TEC oscillation was around 04:15UT near the volcanic eruption, and it was around 04:20 UT at KOKV station in Hawaii. The time-lag of the TEC variations between Samoa and Hawaii obtained by a cross-correlation analysis is 4.5 min or 8.5 min. These time differences are much smaller than the travel time of the seismic waves from the volcano to Hawaii islands. Therefore, it is suggested that the electric field transmitted along geomagnetic field caused the TEC variation observed over Hawaii Islands. A sawtooth waveform of geomagnetic oscillation observed at Apia and Honolulu is analyzed and a possible generation mechanism is discussed. Graphical Abstract: [Figure not available: see fulltext.]

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  23. On the Role of E-F Region Coupling in the Generation of Nighttime MSTIDs During Summer and Equinox: Case Studies Over Northern Germany Reviewed

    Sivakandan, M; Martinis, C; Otsuka, Y; Chau, JL; Norrell, J; Mielich, J; Conte, JF; Stolle, C; Rodríguez-Zuluaga, J; Shinbori, A; Nishioka, M; Tsugawa, T

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 127 ( 5 )   2022.5

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    Simultaneous observations from a 630 nm all-sky airglow imager, GNSS-TEC receivers, and an ionosonde are used to investigate the role of E- and F-region coupling on the generation of medium-scale traveling ionospheric disturbances (MSTIDs). The primary observations are OI 630 nm airglow images taken by an all-sky imager in Kühlungsborn (54.07°N; 11.46°E, 53.79°N Mlat.), a site in northern Germany. Out of 226 nights of observations, MSTIDs were found only in 18 nights, demonstrating the low occurrence rate over Kühlungsborn. We focused on four MSTIDs events: two during the vernal equinox and two during summer. Coincident measurements of detrended GNSS-TEC supported the presence of MSTIDs during the selected events, and simultaneous observations from the ionosonde in Juliusruh (54.60°N, 13.4°E, 54.02°N Mlat.) showed sporadic-E (Es) layer and spread-F activity in the E- and F-region, respectively. We observed the onset of the observed MSTIDs to be around the 15°–20°E longitude and 60–45°N latitude belts. Additionally, we found that in each case, the onset of MSTIDs coincides with the presence of an Es layer with sporadic-E trace is observed (foEs) exceeding 4 MHz. This suggests that an Es layer with foEs ≥ 4MHz was a source of the generation of these MSTIDs. Altitude of the Es layer could be another important factor in generating MSTIDs. The Es layer should exist at an altitude where Hall conductivity is large, as happened in the present study.

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  24. Generation Mechanisms of Plasma Density Irregularity in the Equatorial Ionosphere During a Geomagnetic Storm on 21–22 December 2014 Reviewed

    T. Sori, A. Shinbori, Y. Otsuka, T. Tsugawa, M. Nishioka, A. Yoshikawa

    Journal of Geophysical Research: Space Physics   Vol. 127 ( 5 )   2022.5

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    The equatorial ionosphere endured plasma density irregularities during a geomagnetic storm on 21–22 December 2014. To understand the underlying mechanism, we analyzed the rate of the total electron content change (ROTI) data obtained from a global navigation satellite system, along with solar wind, interplanetary magnetic field (IMF), geomagnetic indices, Jicamarca incoherent scatter radar, and magnetometer data. The results indicate that the ROTI enhancement related to plasma density irregularities (plasma bubbles) occurred three times in the equatorial and low latitude regions of the American sector during the geomagnetic storm. The first, second, and third enhancements which have a longitudinal extent of ∼20° appeared in the post-sunset, pre-midnight, and post-midnight sectors, respectively. The second enhancement occurred during the recovery phase of the storm-time substorm even though the IMF remained southward. During this period, the direction of the dayside equatorial electrojet (EEJ) changed from eastward to westward, while the nightside upward plasma velocity at Jicamarca increased to 28.8 m/s. The response of the EEJ and upward ion drift implies that the westward and eastward electric fields were intensified on the dayside and nightside, respectively. Therefore, these results suggest that an over-shielding electric field penetrates the dayside/nightside equator simultaneously in association with a substorm recovery phase, and that the electric field generates plasma bubbles by the Rayleigh-Taylor instability mechanism. Plasma bubbles induced by the penetration of an over-shielding electric field due to substorm activity have not previously been reported.

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  25. Statistical Behavior of Large-Scale Ionospheric Disturbances From High Latitudes to Mid-Latitudes During Geomagnetic Storms Using 20-yr GNSS-TEC Data: Dependence on Season and Storm Intensity Reviewed

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

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 127 ( 1 )   2022.1

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    To establish the statistical behavior of ionospheric TEC variations from high latitudes to mid-latitudes during the main and recovery phases of geomagnetic storms, we conducted a superposed epoch analysis of interplanetary magnetic field, solar wind, geomagnetic indices (AE and SYM-H), and global navigation satellite system (GNSS)-total electron content (TEC) data for 20 yr (2000–2019). In this study, we identify 663 geomagnetic storm events with the minimum SYM-H value of less than −40 nT and investigate the characteristics of the TEC variations for the weak (−60 ≤ SYM-Hmin < −40 nT), moderate (−100 ≤ SYM-Hmin < −60 nT), and strong (−150 ≤ SYM-Hmin < −100 nT) geomagnetic storms. The main results obtained from the present study are as follows: (a) The TEC enhancements related to the tongue of ionization (TOI), auroral oval, and storm-enhanced density (SED) plume are more dominant in winter than in summer during the main phase of geomagnetic storms. (b) The structure of the mid-latitude trough in the nighttime sector becomes unclear in winter. (c) The TEC depletion at auroral and mid-latitudes (40°–70° GMLAT: geomagnetic latitude) starts to appear in the morning sector (8–10 hr GMLT: geomagnetic local time) during the main phase of geomagnetic storms and the decreased region extends in the lower latitude and GMLT directions with time. The negative storm activity tends to be enhanced significantly as the storm intensity becomes larger. The activity of the TEC depletion is dominant in summer than in winter, which is agreement with the classical ionospheric storm scenario.

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  26. Propagation Direction Analyses of Medium-Scale Traveling Ionospheric Disturbances Observed Over North America With GPS-TEC Perturbation Maps by Three-Dimensional Spectral Analysis Method Reviewed

    Septi Perwitasari, Takuji Nakamura, Takuya Tsugawa, Michi Nishioka, Yoshihiro Tomikawa, Mitsumu K. Ejiri, Masaru Kogure, Yuichi Otsuka, Atsuki Shinbori, Hidekatsu Jin, Chihiro Tao

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 127 ( 1 )   2022.1

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    We applied a novel three-dimensional spectral analysis method to GPS-TEC perturbation (GPS-TECP) maps to study the propagation direction of daytime and nighttime medium-scale traveling ionospheric disturbances (MSTIDs) over North America. By this method, we can automatically calculate the phase velocity spectrum and directionality of MSTIDs. We focused on the periods of high MSTIDs occurrence, namely, June-July 2006 and November-December 2006, to study nighttime and daytime MSTIDs. We divided North America into the west (100 degrees-130 degrees W, 25 degrees-55 degrees N) and east (70 degrees-100 degrees W, 25 degrees-55 degrees N) parts. Our results show that both daytime and nighttime MSTID propagations exhibit strong longitudinal variations as a function of local time and day-to-day variations. The power peaks of daytime MSTIDs are from 10:00-16:00 LT in the west part and 10:00-14:00 LT in the east part. The predominant propagation directions of daytime MSTIDs are southward (southeastward) in the west (east). The daytime local time variations demonstrate that the MSTIDs display directional change in the west part; however, a similar directional change is not very pronounced in the east part. The local time variations of nighttime MSTIDs shows the power peaks from 22:00-02:00 LT in the west and 20:00-00:00 LT in the east. We found that the predominant propagation direction in the west part is westward with a wider azimuthal band (similar to 210 degrees-300 degrees) than the east part (similar to 210 degrees-240 degrees). By comparing nighttime propagation directions between the western and eastern parts, we reached the conclusion that the magnetic declination angle affects the propagation direction.

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  27. Propagation Mechanism of Medium Wave Broadcasting Waves Observed by the Arase Satellite: Hectometric Line Spectra Reviewed

    Kozo Hashimoto, Atsuki Shinbori, Yuichi Otsuka, Fuminori Tsuchiya, Atsushi Kumamoto, Yoshiya Kasahara, Ayako Matsuoka, Isamu Nagano, Yoshizumi Miyoshi, Tatsuhiro Yokoyama

    Journal of Geophysical Research: Space Physics   Vol. 126 ( 11 )   2021.11

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    A new type of terrestrial line spectra found by the Arase satellite was reported in 2018. These spectra are called “hectometric line spectra (HLS)”. They primarily consist of constant frequency narrowband components at frequencies between 525 kHz and 1,700 kHz, which originate and are sometimes amplified from AM broadcasting waves. In addition to these, other generated emissions are observed. Entrances and the mode conversion of the AM broadcasting waves into the equatorial and low-latitude ionosphere with plasma density depletion called plasma bubbles are observed. Electron density profiles and equatorial plasma bubbles are examined through Global Positioning System (GPS)-Total electron content (TEC) analyses. As a result, the Arase satellite which observed the HLS passed through the TEC depression region near the equatorial ionosphere associated with plasma bubbles. The scenario based on the mode conversion of the L-O mode to the Z mode and vice versa was confirmed with observations and GPS-TEC analyses. Another entrance when foF2 estimated from TEC is lower than 1,000 kHz instead of a plasma bubble is also found. No mode conversion is necessary, then.

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  28. Field‐Aligned Electron Density Distribution of the Inner Magnetosphere Inferred From Coordinated Observations of Arase and Van Allen Probes Reviewed

    Yuki Obana, Yukinaga Miyashita, Naomi Maruyama, Atsuki Shinbori, Masahito Nosé, Masafumi Shoji, Atsushi Kumamoto, Fuminori Tsuchiya, Shoya Matsuda, Ayako Matsuoka, Yoshiya Kasahara, Yoshizumi Miyoshi, Iku Shinohara, William S. Kurth, Charles W. Smith, Robert J. MacDowall

    Journal of Geophysical Research: Space Physics   Vol. 126 ( 10 )   2021.10

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  29. Plasma depletions lasting into daytime during the recovery phase of a geomagnetic storm in May 2017: Analysis and simulation of GPS total electron content observations Reviewed

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

    EARTH AND PLANETARY PHYSICS   Vol. 5 ( 5 ) page: 427 - 434   2021.9

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    This paper reports that plasma density depletions appearing at middle latitudes near sunrise survived until afternoon on 29 May 2017 during the recovery phase of a geomagnetic storm. By analyzing GPS data collected in Japan, we investigate temporal variations in the horizontal two-dimensional distribution of total electron content (TEC) during the geomagnetic storm. The SYM-H index reached −142 nT around 08 UT on 28 May 2017. TEC depletions extending up to approximately 38°N along the meridional direction appeared over Japan around 05 LT (LT = UT + 9 hours) on 29 May 2017, when TEC rapidly increased at sunrise due to the solar extreme ultraviolet (EUV) radiation. The TEC depletions appeared sequentially over Japan for approximately 8 hours in sunlit conditions. At 06 LT on 29 May, when the plasma depletions first appeared over Japan, the background TEC was enhanced to approximately 17 TECU, and then decreased to approximately 80% of the TEC typical of magnetically quiet conditions. We conclude that this temporal variation of background plasma density in the ionosphere was responsible for the persistence of these plasma depletions for so long in daytime. By using the Naval Research Laboratory: Sami2 is Another Model of the Ionosphere (SAMI2), we have evaluated how plasma production and ambipolar diffusion along the magnetic field may affect the rate of plasma depletion disappearance. Simulation shows that the plasma density increases at the time of plasma depletion appearance; subsequent decreases in the plasma density appear to be responsible for the long-lasting persistence of plasma depletions during daytime. The plasma density depletion in the top side ionosphere is not filled by the plasma generated by the solar EUV productions because plasma production occurs mainly at the bottom side of the ionosphere.

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  30. Evidence for the In-Situ Generation of Plasma Depletion Structures Over the Transition Region of Geomagnetic Low-Mid Latitude Reviewed

    Sivakandan, M; Mondal, S; Sarkhel, S; Chakrabarty, D; Krishna, MVS; Upadhayaya, AK; Shinbori, A; Sori, T; Kannaujiya, S; Ray, PKC

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 126 ( 9 )   2021.9

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    On a geomagnetic quiet night of October 29, 2018, we captured an observational evidence of the onset of dark band structures within the field-of-view of an all-sky airglow imager operating at 630.0 nm over a geomagnetic low-mid latitude transition region, Hanle, Leh Ladakh. Simultaneous ionosonde observations over New Delhi shows the occurrence of spread-F in the ionograms. Additionally, virtual and peak height indicate vertical upliftment in the F layer altitude and reduction in the ionospheric peak frequency were also observed when the dark band pass through the ionosonde location. All these results confirmed that the observed depletions are indeed associated with ionospheric F region plasma irregularities. The rate of total electron content index (ROTI) indicates the absence of plasma bubble activities over the equatorial/low latitude region which confirms that the observed event is a mid-latitude plasma depletion. Our calculations reveal that the growth time of the plasma depletion is ∼2 h if one considers only the Perkins instability mechanism. This is not consistent with the present observations as the plasma depletion developed within ∼25 min. By invoking possible Es layer instabilities and associated E-F region coupling, we show that the growth rate increases roughly by an order of magnitude. This strongly suggests that the Cosgrove and Tsunoda mechanism may be simultaneously operational in this case. Furthermore, it is also suggested that reduced F region flux-tube integrated conductivity in the southern part of onset region created conducive background conditions for the growth of the plasma depletion on this night.

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  31. Relationship Between the Locations of the Midlatitude Trough and Plasmapause Using GNSS‐TEC and Arase Satellite Observation Data Reviewed

    Atsuki Shinbori, Yuichi Otsuka, Takuya Tsugawa, Michi Nishioka, Atsushi Kumamoto, Fuminori Tsuchiya, Shoya Matsuda, Yoshiya Kasahara, Ayako Matsuoka

    Journal of Geophysical Research: Space Physics   Vol. 126 ( 5 )   2021.5

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  32. Simultaneous Observation of Two Isolated Proton Auroras at Subauroral Latitudes by a Highly Sensitive All-Sky Camera and Van Allen Probes Reviewed

    Nakamura, K; Shiokawa, K; Otsuka, Y; Shinbori, A; Miyoshi, Y; Connors, M; Spence, H; Reeves, G; Funsten, HO; MacDowall, R; Smith, C; Wygant, J; Bonnell, J

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 126 ( 5 )   2021.5

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    Isolated proton auroras (IPAs) appearing at subauroral latitudes are generated by energetic protons precipitating from the magnetosphere through interaction with electromagnetic ion cyclotron (EMIC) waves. An IPA thus indicates the spatial scale and temporal variation of wave-particle interactions in the magnetosphere. In this study, a unique event of simultaneous ground and magnetospheric satellite observations of two IPAs were conducted on March 16, 2015, using an all-sky imager at Athabasca, Canada and Van Allen Probes. The Van Allen Probes observed two isolated EMIC waves with frequencies of ∼1 and 0.4 Hz at L ≈ 5.0 when the satellite footprint crossed over the two IPAs. This suggests that the IPAs were caused by localized EMIC waves. Proton flux at 5–20 keV increased locally when the EMIC waves appeared. Electron flux at energies below ∼500 eV also increased. Temperature anisotropy of the energetic protons was estimated at 1.5–2.5 over a wide L-value range of 3.0–5.2. Electron density gradually decreased from L = 3.5 to 5.4, suggesting that the EMIC wave at L ≈ 5.0 was located in the gradual plasmapause. From these observations, we conclude that the localized IPAs and associated EMIC waves took place because of localized enhancement of energetic proton flux and plasma density structure near the plasmapause. The magnetic field observed by the satellite showed small variation during the wave observation, indicating that the IPAs were accompanied by the weak field-aligned current.

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  33. The Occurrence Feature of Plasma Bubbles in the Equatorial to Midlatitude Ionosphere During Geomagnetic Storms Using Long-Term GNSS-TEC Data Reviewed

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

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 126 ( 5 )   2021.5

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    We performed a superposed epoch analysis of solar wind, interplanetary magnetic field, geomagnetic index, and the rate of total electron content (TEC) index (ROTI) derived from global navigation satellite system-TEC data during 652 geomagnetic storm events (minimum SYM-H < −40 nT), to clarify the occurrence features and causes of storm-time plasma bubbles in the equatorial to mid-latitude ionosphere. In this analysis, we defined the time of the SYM-H minimum as the zero epoch. As a result, the ROTI enhancement started at the duskside magnetic equator and expanded to higher latitudes during the main phase. Approximately 1 h after the onset of the recovery phase, the ROTI values at the magnetic equator in the dusk-to-midnight sectors decreased while those in the dawn sector increased. This situation persisted for at least 12 h. The ratio of the ROTI during the main phase to that during the quiet period in the dusk sector is the largest in May–July. The ratio of the ROTI during the recovery phase decreased during dusk with increasing solar activity. Considering the requirement of the Rayleigh-Taylor instability, the difference in the magnetic local time of the ROTI signature, between the main and recovery phases, can be explained by a local time distribution of storm-time electric fields associated with a prompt penetration electric field and disturbance dynamo. This implies that the occurrence feature of the plasma bubble is different from that during quiet times when the input of solar wind energy to the magnetosphere and ionosphere increases significantly.

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  34. Model-based reproduction and validation of the total spectra of a solar flare and their impact on the global environment at the X9.3 event of September 6, 2017 Reviewed

    Kyoko Watanabe, Hidekatsu Jin, Shohei Nishimoto, Shinsuke Imada, Toshiki Kawai, Tomoko Kawate, Yuichi Otsuka, Atsuki Shinbori, Takuya Tsugawa, Michi Nishioka

    Earth, Planets and Space   Vol. 73 ( 1 )   2021.4

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    <title>Abstract</title>We attempted to reproduce the total electron content (TEC) variation in the Earth's atmosphere from the temporal variation of the solar flare spectrum of the X9.3 flare on September 6, 2017. The flare spectrum from the Flare Irradiance Spectral Model (FISM), and the flare spectrum from the 1D hydrodynamic model, which considers the physics of plasma in the flare loop, are used in the GAIA model, which is a simulation model of the Earth's whole atmosphere and ionosphere, to calculate the TEC difference. We then compared these results with the observed TEC. When we used the FISM flare spectrum, the difference in TEC from the background was in a good agreement with the observation. However, when the flare spectrum of the 1D-hydrodynamic model was used, the result varied depending on the presence or absence of the background. This difference depending on the models is considered to represent which extreme ultraviolet (EUV) radiation is primarily responsible for increasing TEC. From the flare spectrum obtained from these models and the calculation result of TEC fluctuation using GAIA, it is considered that the enhancement in EUV emission by approximately 15<bold>–</bold>35 nm mainly contributes in increasing TEC rather than that of X-ray emission, which is thought to be mainly responsible for sudden ionospheric disturbance. In addition, from the altitude/wavelength distribution of the ionization rate of Earth's atmosphere by GAIA (Ground-to-topside Atmosphere and Ionosphere model for Aeronomy), it was found that EUV radiation of approximately 15<bold>–</bold>35 nm affects a wide altitude range of 120<bold>–</bold>300 km, and TEC enhancement is mainly caused by the ionization of nitrogen molecules.

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  35. Multi‐Event Analysis of Plasma and Field Variations in Source of Stable Auroral Red (SAR) Arcs in Inner Magnetosphere During Non‐Storm‐Time Substorms Reviewed

    Yudai Inaba, Kazuo Shiokawa, Shin‐ichiro Oyama, Yuichi Otsuka, Martin Connors, Ian Schofield, Yoshizumi Miyoshi, Shun Imajo, Atsuki Shinbori, Artem Yu Gololobov, Yoichi Kazama, Shiang‐Yu Wang, Sunny W. Y. Tam, Tzu‐Fang Chang, Bo‐Jhou Wang, Kazushi Asamura, Shoichiro Yokota, Satoshi Kasahara, Kunihiro Keika, Tomoaki Hori, Ayako Matsuoka, Yoshiya Kasahara, Atsushi Kumamoto, Shoya Matsuda, Yasumasa Kasaba, Fuminori Tsuchiya, Masafumi Shoji, Masahiro Kitahara, Satoko Nakamura, Iku Shinohara, Harlan E. Spence, Geoff D. Reeves, Robert J. Macdowall, Charles W. Smith, John R. Wygant, John W. Bonnell

    Journal of Geophysical Research: Space Physics   Vol. 126 ( 4 )   2021.4

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  36. Comparison of seasonal and longitudinal variation of daytime MSTID activity using GPS observation and GAIA simulations Reviewed

    Sivakandan, M; Otsuka, Y; Ghosh, P; Shinagawa, H; Shinbori, A; Miyoshi, Y

    EARTH PLANETS AND SPACE   Vol. 73 ( 1 )   2021.2

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    The total electron content (TEC) data derived from the GAIA (Ground-to-topside model of Atmosphere Ionosphere for Aeronomy) is used to study the seasonal and longitudinal variation of occurrence of medium-scale traveling ionospheric disturbances (MSTIDs) during daytime (09:00–15:00 LT) for the year 2011 at eight locations in northern and southern hemispheres, and the results are compared with ground-based Global Positioning System (GPS)-TEC. To derive TEC variations caused by MSTIDs from the GAIA (GPS) data, we obtained detrended TEC by subtracting 2-h (1-h) running average from the TEC, and calculated standard deviation of the detrended TEC in 2 h (1 h). MSTID activity was defined as a ratio of the standard deviation to the averaged TEC. Both GAIA simulation and GPS observations data show that daytime MSTID activities in the northern and southern hemisphere (NH and SH) are higher in winter than in other seasons. From the GAIA simulation, the amplitude of the meridional wind variations, which could be representative of gravity waves (GWs), shows two peaks in winter and summer. The winter peak in the amplitude of the meridional wind variations coincides with the winter peak of the daytime MSTIDs, indicating that the high GW activity is responsible for the high MSTID activity. On the other hand, the MSTID activity does not increase in summer. This is because the GWs in the thermosphere propagate poleward in summer, and equatorward in winter, and the equatorward-propagating GWs cause large plasma density perturbations compared to the poleward-propagating GWs. Longitudinal variation of daytime MSTID activity in winter is seen in both hemispheres. The MSTID activity during winter in the NH is higher over Japan than USA, and the MSTID activity during winter in the SH is the highest in South America. In a nutshell, GAIA can successfully reproduce the seasonal and longitudinal variation of the daytime MSTIDs. This study confirms that GWs cause the daytime MSTIDs in GAIA and amplitude and propagation direction of the GWs control the noted seasonal variation. GW activities in the middle and lower atmosphere cause the longitudinal variation. [Figure not available: see fulltext.].

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  37. Solar activity dependence of medium-scale traveling ionospheric disturbances using GPS receivers in Japan Reviewed

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

    EARTH PLANETS AND SPACE   Vol. 73 ( 1 )   2021.1

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    In order to reveal solar activity dependence of the medium-scale traveling ionospheric disturbances (MSTIDs) at midlatitudes, total electron content (TEC) data obtained from a Global Positioning System (GPS) receiver network in Japan during 22 years from 1998 to 2019 were analyzed. We have calculated the detrended TEC by subtracting the 1-h running average from the original TEC data for each satellite and receiver pair, and made two-dimensional TEC maps of the detrended TEC with a spatial resolution of 0.15° × 0.15° in longitude and latitude. We have investigated MSTID activity, defined as δI/ I¯ , where δI and I¯ are standard deviation of the detrended TEC and the average vertical TEC within the area of 133.0°–137.0° E and 33.0°–37.0° N for 1 h, respectively. From each 2-h time series of the detrended TEC data within the same area as the MSTID activity, auto-correlation functions (ACFs) of the detrended TEC were calculated to estimate the horizontal propagation velocity and direction of the MSTIDs. Statistical results of the MSTID activity and propagation direction of MSTIDs were consistent with previous studies and support the idea that daytime MSTIDs could be caused by atmospheric gravity waves, and that nighttime MSTIDs were caused by electro-dynamical forces, such as the Perkins instability. From the current long-term observations, we have found that the nighttime MSTID activity and occurrence rate increased with decreasing solar activity. For the daytime MSTID, the occurrence rate increased with decreasing solar activity, whereas the MSTID activity did not show distinct solar activity dependence. These results suggest that the secondary gravity waves generated by dissipation of the primary gravity waves propagating from below increase under low solar activity conditions. The mean horizontal phase velocity of the MSTIDs during nighttime did not show a distinct solar activity dependence, whereas that during daytime showed an anticorrelation with solar activity. The horizontal phase velocity of the daytime MSTIDs was widely distributed from 40 to 180 m/s under high solar activity conditions, whereas it ranged between 80 and 200 m/s, with a maximum occurrence at 130 m/s under low solar activity conditions, suggesting that gravity waves with low phase velocity could be dissipated by high viscosity in the thermosphere under low solar activity conditions. [Figure not available: see fulltext.]

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  38. Plasma and Field Observations in the Magnetospheric Source Region of a Stable Auroral Red (SAR) Arc by the Arase Satellite on 28 March 2017 Reviewed

    Yudai Inaba, Kazuo Shiokawa, Shin‐ichiro Oyama, Yuichi Otsuka, Arto Oksanen, Atsuki Shinbori, Artem Yu Gololobov, Yoshizumi Miyoshi, Yoichi Kazama, Shiang‐Yu Wang, Sunny W. Y. Tam, Tzu‐Fang Chang, Bo‐Jhou Wang, Shoichiro Yokota, Satoshi Kasahara, Kunihiro Keika, Tomoaki Hori, Ayako Matsuoka, Yoshiya Kasahara, Atsushi Kumamoto, Yasumasa Kasaba, Fuminori Tsuchiya, Masafumi Shoji, Iku Shinohara, Claudia Stolle

    Journal of Geophysical Research: Space Physics   Vol. 125 ( 10 )   2020.10

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  39. An Ephemeral Red Arc Appeared at 68° MLat at a Pseudo Breakup During Geomagnetically Quiet Conditions Reviewed

    S. Oyama, A. Shinbori, Y. Ogawa, M. Kellinsalmi, T. Raita, A. Aikio, H. Vanhamäki, K. Shiokawa, I. Virtanen, L. Cai, A. B. Workayehu, M. Pedersen, K. Kauristie, T. T. Tsuda, B. Kozelov, A. Demekhov, A. Yahnin, F. Tsuchiya, A. Kumamoto, Y. Kasahara, A. Matsuoka, M. Shoji, M. Teramoto, M. Lester

    Journal of Geophysical Research: Space Physics   Vol. 125 ( 10 )   2020.10

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  40. Temporal and Spatial Variations of Total Electron Content Enhancements During a Geomagnetic Storm on 27 and 28 September 2017 Reviewed

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

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

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    Temporal and spatial evolutions of total electron content (TEC) and electron density in the ionosphere during a geomagnetic storm that occurred on 27 and 28 September 2017 have been investigated using global TEC data obtained from many Global Navigation Satellite System stations together with the ionosonde, geomagnetic field, Jicamarca incoherent scatter and Super Dual Auroral Radar Network (SuperDARN) radar data. Our analysis results show that a clear enhancement of the ratio of the TEC difference (rTEC) first occurs from noon to afternoon at high latitudes within 1 hr after a sudden increase and expansion of the high-latitude convection and prompt penetration of the electric field to the equator associated with the southward excursion of the interplanetary magnetic field. Approximately 1–2 hr after the onset of the hmF2 increase in the midlatitude and low-latitude regions associated with the high-latitude convection enhancement, the rTEC and foF2 values begin to increase and the enhanced rTEC region expands to low latitudes within 1–2 hr. This signature suggests that the ionospheric plasmas in the F2 region move at a higher altitude due to local electric field drift, where the recombination rate is smaller, and that the electron density increases due to additional production at the lower altitude in the sunlit region. Later, another rTEC enhancement related to the equatorial ionization anomaly appears in the equatorial region approximately 1 hr after the prompt penetration of the electric field to the equator and expands to higher latitudes within 3–4 hr.

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

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

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

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  42. Observation and characterization of traveling ionospheric disturbances induced by solar eclipse of 20 March 2015 using incoherent scatter radars and GPS networks Reviewed

    Panasenko Sergii V, Otsuka Yuichi, van de Kamp Max, Chernogor Leonid F, Shinbori Atsuki, Tsugawa Takuya, Nishioka Michi

    JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS   Vol. 191   2019.9

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  43. Direct Observations of Traveling Ionospheric Disturbances as Focusers of Solar Radiation: Spectral Caustics Reviewed

    Koval Artem, Chen Yao, Tsugawa Akuya, Otsuka Yuichi, Shinbori Atsuki, Nishioka Michi, Brazhenko Anatoliy, Stanislaysky Aleksander, Konovalenko Aleksander, Zhang Qing-He, Monstein Christian, Gorgutsa Roman

    ASTROPHYSICAL JOURNAL   Vol. 877 ( 2 )   2019.6

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  44. Response of the Ionosphere-Plasmasphere Coupling to the September 2017 Storm: What Erodes the Plasmasphere so Severely? Reviewed

    Obana, Y, N. Maruyama, A. Shinbori, K. Hashimoto, M. Fedrizzi, M. Nose, Y. Otsuka, N. Nishitani, T. Hori, A. Kumamoto, F. Tsuchiya, S. Matsuda, A. Matsuoka, Y. Kasahara, A. Yoshikawa, Y. Miyoshi, I. Shinohara

    Space Weather   Vol. 17 ( 6 ) page: 861 - 876   2019.6

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  45. Relationship between the low-latitude coronal hole area, solar wind velocity, and geomagnetic activity during solar cycles 23 and 24 Reviewed

    Nakagawa Yumi, Nozawa Satoshi, Shinbori Atsuki

    EARTH PLANETS AND SPACE   Vol. 71 ( 1 )   2019.2

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    DOI: 10.1186/s40623-019-1005-y

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  46. The Space Physics Environment Data Analysis System (SPEDAS) Reviewed

    Angelopoulos V., Cruce P., Drozdov A., Grimes E. W., Hatzigeorgiu N., King D. A., Larson D., Lewis J. W., McTiernan J. M., Roberts D. A., Russell C. L., Hori T., Kasahara Y., Kumamoto A., Matsuoka A., Miyashita Y., Miyoshi Y., Shinohara I., Teramoto M., Faden J. B., Halford A. J., McCarthy M., Millan R. M., Sample J. G., Smith D. M., Woodger L. A., Masson A., Narock A. A., Asamura K., Chang T. F., Chiang C. -Y., Kazama Y., Keika K., Matsuda S., Segawa T., Seki K., Shoji M., Tam S. W. Y., Umemura N., Wang B. -J., Wang S. -Y., Redmon R., Rodriguez J. V., Singer H. J., Vandegriff J., Abe S., Nose M., Shinbori A., Tanaka Y. -M., UeNo S., Andersson L., Dunn P., Fowler C., Halekas J. S., Hara T., Harada Y., Lee C. O., Lillis R., Mitchell D. L., Argall M. R., Bromund K., Burch J. L., Cohen I. J., Galloy M., Giles B., Jaynes A. N., Le Contel O., Oka M., Phan T. D., Walsh B. M., Westlake J., Wilder F. D., Bale S. D., Livi R., Pulupa M., Whittlesey P., DeWolfe A., Harter B., Lucas E., Auster U., Bonnell J. W., Cully C. M., Donovan E., Ergun R. E., Frey H. U., Jackel B., Keiling A., Korth H., McFadden J. P., Nishimura Y., Plaschke F., Robert P., Turner D. L., Weygand J. M., Candey R. M., Johnson R. C., Kovalick T., Liu M. H., McGuire R. E., Breneman A., Kersten K., Schroeder P.

    SPACE SCIENCE REVIEWS   Vol. 215 ( 1 ) page: 9   2019.2

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    DOI: 10.1007/s11214-018-0576-4

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  47. The Space Physics Environment Data Analysis System (SPEDAS) Reviewed

    V Angelopoulos, P Cruce, A Drozdov, EW Grimes, N Hatzigeorgiu, DA King, D Larson, JW Lewis, JM McTiernan, DA Roberts, CL Russell, T Hori, Y Kasahara, A Kumamoto, A Matsuoka, Y Miyashita, Y Miyoshi, I Shinohara, M Teramoto, JB Faden, AJ Halford, M McCarthy, RM Millan, JG Sample, DM Smith, LA Woodger, A Masson, AA Narock, K Asamura, TF Chang, C-Y Chiang, Y Kazama, K Keika, S Matsuda, T Segawa, K Seki, M Shoji, SWY Tam, N Umemura, B-J Wang, S-Y Wang, R Redmon, JV Rodriguez, HJ Singer, J Vandegriff, S Abe, M Nose, A Shinbori, Y-M Tanaka, S UeNo, L Andersson, P Dunn, C Fowler, JS Halekas, T Hara, Y Harada, CO Lee, R Lillis, DL Mitchell, MR Argall, K Bromund, JL Burch, IJ Cohen, M Galloy, B Giles, AN Jaynes, O Le Contel, M Oka, TD Phan, BM Walsh, J Westlake, FD Wilder, SD Bale, R Livi, M Pulupa, P Whittlesey, A DeWolfe, B Harter, E Lucas, U Auster, JW Bonnell, CM Cully, E Donovan, RE Ergun, HU Frey, B Jackel, A Keiling, H Korth, JP McFadden, Y Nishimura, F Plaschke, P Robert, DL Turner, JM Weygand, RM Candey, RC Johnson, T Kovalick, MH Liu, RE McGuire, A Breneman, K Kersten, P Schroeder

    Space Sci. Rev.   Vol. 215 ( 1 ) page: 9   2019.1

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  48. Temporal and Spatial Variations of Mid-Latitude Ionospheric Trough during a Geomagnetic Storm Based on Global GNSS-TEC and Arase Satellite Observations Reviewed

    Shinbori A., Otsuka Y., Tsugawa T., Nishioka M., Kumamoto A., Tsuchia F., Matsuda S., Kasahara Y.

    2018 2nd URSI Atlantic Radio Science Meeting, AT-RASC 2018     2018.9

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    The Earth's plasmasphere is the vast 'doughnut' shaped dense plasma region of the magnetosphere that is filled with cold ions and electrons of ionospheric origin. The plasmaspheric plasma density shows an abrupt drop by a factor of 5 or more around 4-6 Re (Re: Earth's radius). The boundary has been called 'plasmapause'. Since the plasmaspheric cold plasma controls generation of plasma waves, their propagation features, and particle acceleration via wave-particle interaction, detailed investigation of the temporal and spatial variations of the plasmasphere and plasmapause location during a geomagnetic storm is important for understanding a change in plasma wave environments in the inner magnetosphere. Recent studies showed a good correlation between the mid-latitude ionospheric trough and the plasmapause for both geomagnetically quiet and disturbed conditions [1]. However, they did not reach the detailed investigation of the characteristics of spatial variation of the mid-latitude ionospheric trough and its temporal variation with high resolution due to limitation of a usage of global GIM of TEC. In this study, we investigate characteristics of temporal and spatial variations of the mid-latitude ionospheric trough during a geomagnetic storm which occurred on April 4, 2017 using the 5-min average Global Navigation Satellite System (GNSS) Total Electron Content (TEC) data together with solar wind, interplanetary magnetic field, geomagnetic field, and Arase High Frequency Analyzer (HFA) (subcomponent of Plasma Wave Experiment (PWE)) observation data. As a result, the location of the mid-latitude ionospheric trough moves equatorward from 60 to 48 degrees within 4 hours after the onset of the storm main phase. The movement speed increases from 1.3 to 3.5 degrees of geomagnetic latitude per hour after the onset of storm-time substorm. The increasing speed means an abrupt shrink of the plasmasphere due to a sudden enhancement of convection electric field in the inner magnetosphere associated with the substorm onset. The location of the mid-latitude ionospheric trough identified from the minimum value of the GNSS-TEC data from the auroral to mid-latitude regions is almost in good agreement with that of an abrupt drop of electron density derived from the upper limit frequency of the upper hybrid resonance (UHR) waves detected by the HFA instrument onboard the Arase satellite. In this case, the electron density profile along the Arase orbit shows an irregular variation of the electron density near the plasmapause. During the main phase of the geomagnetic storm, the geomagnetic longitude distribution of the mid-latitude trough location shows a wavy structure with its scale of 1000-2500 km. The shape of the wavy structure varies with time during the storm main phase. This phenomenon has not yet been reported before due to the limitation of ground dense GNSS receiver networks. After the start of the recovery phase of the geomagnetic storm, the mid-latitude ionospheric trough quickly moves poleward from 48 to 60 degrees in geomagnetic latitude within 4 hours in a geomagnetic longitude range of 310-360 degrees in geomagnetic longitude. The average speed of the poleward movement is 2.3 degrees of geomagnetic latitude per hour.

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  49. Temporal and spatial variations of storm-time mid-latitude ionospheric trough based on global GNSS-TEC and Arase satellite observations Reviewed

    Shinbori, A, Y. Otsuka, T. Tsugawa, M. Nishioka, A. Kumamoto, F. Tsuchia, S. Matsuda, Y. Kasahara, A. Matsuoka, J. M. Ruohoniemi, S. G. Shepherd, N. Nishitani

    Geophys. Res. Lett.   Vol. 45 ( 15 ) page: 7362 - 7370   2018.8

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  50. Total Electron Content Observations by Dense Regional and Worldwide International Networks of GNSS

    Tsugawa Takuya, Nishioka Michi, Ishii Mamoru, Hozumi Kornyanat, Saito Susumu, Shinbori Atsuki, Otsuka Yuichi, Saito Akinori, Buhari Suhaila M., Abdullah Mardina, Supnithi Pornchai

    JOURNAL OF DISASTER RESEARCH   Vol. 13 ( 3 ) page: 535-545   2018.6

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  51. Total Electron Content Observations by Dense Regional and Worldwide International Networks of GNSS

    Tsugawa Takuya, Nishioka Michi, Ishii Mamoru, Hozumi Kornyanat, Saito Susumu, Shinbori Atsuki, Otsuka Yuichi, Saito Akinori, Buhari Suhaila M., Abdullah Mardina, Supnithi Pornchai

    Journal of Disaster Research   Vol. 13 ( 3 ) page: 535 - 545   2018.6

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    <p>Two-dimensional ionospheric total electron content (TEC) maps have been derived from ground-based Global Navigation Satellite System (GNSS) receiver networks and applied to studies of various ionospheric disturbances since the mid-1990s. For the purpose of monitoring and researching ionospheric conditions and ionospheric space weather phenomena, we have developed TEC maps of areas over Japan using the dense GNSS network, GNSS Earth Observation NETwork (GEONET), which consists of about 1300 stations and is operated by the Geospatial Information Authority of Japan (GSI). Currently, we are providing high-resolution, two-dimensional maps of absolute TEC, detrended TEC, rate of TEC change index (ROTI), and loss-of-lock on GPS signal over Japan on a real-time basis. Such high-resolution TEC maps using dense GNSS receiver networks are one of the most effective ways to observe, on a scale of several 100 km to 1000 km, ionospheric variations caused by traveling ionospheric disturbances and/or equatorial plasma bubbles, which can degrade single-frequency and differential GNSS positioning/navigation. We have collected all the available GNSS receiver data in the world to expand the TEC observation area. Currently, however, dense GNSS receiver networks are available in only limited areas, such as Japan, North America, and Europe. To expand the two-dimensional TEC observation with high resolution, we have conducted the Dense Regional and Worldwide International GNSS TEC observation (DRAWING-TEC) project, which is engaged in three activities: (1) standardizing GNSS-TEC data, (2) developing a new high-resolution TEC mapping technique, and (3) sharing the standardized TEC data or the information of GNSS receiver network. We have developed a new standardized TEC format, GNSS-TEC EXchange (GTEX), which is included in the Formatted Tables of ITU-R SG 3 Databanks related to Recommendation ITU-R P.311. Sharing the GTEX TEC data would be easier than sharing the GPS/GNSS data among those in the international ionospheric researcher community. The DRAWING-TEC project would promote studies of medium-scale ionospheric variations and their effect on GNSS.</p>

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  52. Temporal and spatial variations of mid-latitude ionospheric trough during a geomagnetic storm based on global GNSS-TEC and Arase satellite observations Reviewed

    Shinbori Atsuki, Otsuka Yuichi, Tsugawa Takuya, Nishioka Michi, Kumamoto Atsushi, Tsuchia Fuminori, Matsuda Shoya, Kasahara Yoshiya

    2018 2ND URSI ATLANTIC RADIO SCIENCE MEETING (AT-RASC)     page: .   2018

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  53. Wire Probe Antenna (WPT) and Electric Field Detector (EFD) of Plasma Wave Experiment (PWE) aboard the Arase satellite Reviewed

    Kasaba, Y, K. Ishisaka, Y. Kasahara, T. Imachi, S. Yagitani, H. Kojima, S. Matsuda, M. Shoji, S. Kurita, T. Hori, A. Shinbori, M. Teramoto, Y. Miyoshi, T. Nakagawa, N. Takahashi, Y. Nishimura, A. Matsuoka, A. Kumamoto, F. Tsuchiya, R. Nomura

    Earth Planets Space   Vol. 69 ( 174 )   2017.12

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  54. Ground-based instruments of the PWING project to investigate dynamics of the inner magnetosphere at subauroral latitudes as a part of the ERG-ground coordinated observation network Reviewed

    Kazuo Shiokawa, Yasuo Katoh, Yoshiyuki Hamaguchi, Yuka Yamamoto, Takumi Adachi, Mitsunori Ozaki, Shin-Ichiro Oyama, Masahito Nose, Tsutomu Nagatsuma, Yoshimasa Tanaka, Yuichi Otsuka, Yoshizumi Miyoshi, Ryuho Kataoka, Yuki Takagi, Yuhei Takeshita, Atsuki Shinbori, Satoshi Kurita, Tomoaki Hori, Nozomu Nishitani, Iku Shinohara, Fuminori Tsuchiya, Yuki Obana, Shin Suzuki, Naoko Takahashi, Kanako Seki, Akira Kadokura, Keisuke Hosokawa, Yasunobu Ogawa, Martin Connors, J. Michael Ruohoniemi, Mark Engebretson, Esa Turunen, Thomas Ulich, Jyrki Manninen, Tero Raita, Antti Kero, Arto Oksanen, Marko Back, Kirsti Kauristie, Jyrki Mattanen, Dmitry Baishev, Vladimir Kurkin, Alexey Oinats, Alexander Pashinin, Roman Vasilyev, Ravil Rakhmatulin, William Bristow, Marty Karjala

    EARTH PLANETS AND SPACE   Vol. 69 ( 1 )   2017.11

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    The plasmas (electrons and ions) in the inner magnetosphere have wide energy ranges from electron volts to mega-electron volts (MeV). These plasmas rotate around the Earth longitudinally due to the gradient and curvature of the geomagnetic field and by the co-rotation motion with timescales from several tens of hours to less than 10 min. They interact with plasma waves at frequencies of mHz to kHz mainly in the equatorial plane of the magnetosphere, obtain energies up to MeV, and are lost into the ionosphere. In order to provide the global distribution and quantitative evaluation of the dynamical variation of these plasmas and waves in the inner magnetosphere, the PWING project (study of dynamical variation of particles and waves in the inner magnetosphere using ground-based network observations, http://www.isee.nagoya-u.ac.jp/dimr/PWING/) has been carried out since April 2016. This paper describes the stations and instrumentation of the PWING project. We operate all-sky airglow/aurora imagers, 64-Hz sampling induction magnetometers, 40-kHz sampling loop antennas, and 64-Hz sampling riometers at eight stations at subauroral latitudes (similar to 60 degrees geomagnetic latitude) in the northern hemisphere, as well as 100-Hz sampling EMCCD cameras at three stations. These stations are distributed longitudinally in Canada, Iceland, Finland, Russia, and Alaska to obtain the longitudinal distribution of plasmas and waves in the inner magnetosphere. This PWING longitudinal network has been developed as a part of the ERG (Arase)-ground coordinated observation network. The ERG (Arase) satellite was launched on December 20, 2016, and has been in full operation since March 2017. We will combine these ground network observations with the ERG (Arase) satellite and global modeling studies. These comprehensive datasets will contribute to the investigation of dynamical variation of particles and waves in the inner magnetosphere, which is one of the most important research topics in recent space physics, and the outcome of our research will improve safe and secure use of geospace around the Earth.

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  55. Characteristics of Seasonal Variation and Solar Activity Dependence of the Geomagnetic Solar Quiet Daily Variation Reviewed

    Atsuki Shinbori, Yukinobu Koyama, Masahito Nos{\'{e, Tomoaki Hori, Yuichi Otsuka

    Journal of Geophysical Research: Space Physics   Vol. 122 ( 10 ) page: 10796 - 10810   2017.10

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  56. Propagation and evolution of electric fields associated with solar wind pressure pulses based on spacecraft and ground-based observations Reviewed

    N. Takahashi, Y. Kasaba, Y. Nishimura, A. Shinbori, T. Kikuchi, T. Hori, Y. Ebihara, N. Nishitani

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 122 ( 8 ) page: 8446 - 8461   2017.8

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    We investigate spatial and temporal evolution of large-scale electric fields in the magnetosphere and ionosphere associated with sudden commencements (SCs) using multipoint equatorial magnetospheric (THEMIS, RBSP, and GOES) and ionospheric (C/NOFS) satellites with radars (SuperDARN). A distinct SC event on 17 March 2013 shows that the magnetospheric electric field in the equatorial plane propagates from dayside toward nightside as a fast-mode wave. The ionospheric electric field responds similar to 41s after the onset of dayside magnetospheric electric field, which can be explained by the propagation of the Alfven wave along magnetic field lines. The wavelet analysis shows that the Alfven wave is dominant in the plasmasphere. Poynting fluxes toward the ionosphere support these propagations. From a statistical analysis of response time, tailward propagation speed is estimated at about 1000-1100km/s. We also statistically derive a spatial distribution and time evolution of the magnetospheric electric field in the dawn-dusk direction (E-y). Our result shows that negative E-y (dawnward) propagates from noon toward the magnetotail, followed by positive E-y (duskward). The propagation characteristics of electric fields in the equatorial plane depend on magnetic local time. At noon, negative E-y lasts for about 1min, and positive E-y becomes dominant about 2min after the SC onset. Negative E-y soon attenuates in the nightside region, while the positive E-y propagates fairly well to the premidnight or postmidnight regions while maintaining a certain amplitude. The enhancement of positive E-y is due to the enhancement of magnetospheric convection associated with the main impulse of SCs.

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    Other Link: http://orcid.org/0000-0002-8160-3553

  57. 京大RISHにおける生存圏データベースの公開

    橋口浩之, 津田敏隆, 塩谷雅人, 山本衛, 杉山淳司, 新堀淳樹

    科学データ研究会・WDS国内シンポジウム     2017.3

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  58. 生存圏アジアリサーチノード

    津田敏隆, 橋口浩之, 森拓郎, 新堀淳樹

    生存圏ミッションシンポジウム     2017.2

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  59. Thermal and Low-energy Ion Outflows in and through the Polar Cap Reviewed

    Naritoshi Kitamura, Kanako Seki, Yukitoshi Nishimura, Takumi Abe, Manabu Yamada, Shigeto Watanabe, Atsushi Kumamoto, Atsuki Shinbori, Andrew W. Yau

    Magnetosphere-Ionosphere Coupling in the Solar System     page: 91 - 100   2016.10

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  60. Evaluation of momentum flux with radar Reviewed

    Dennis M. Riggin, Toshitaka Tsuda, Atsuki Shinbori

    JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS   Vol. 142   page: 98 - 107   2016.5

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    The statistics of gravity wave momentum flux estimation are investigated using data from the MU radar at Shigariki, Japan (136 degrees E, 35 degrees N). The radar has been operating during campaign periods since 1986. The first part of the paper focuses on a multi-day campaign during October 13-31, 1986. The second part of the paper investigates data after 2006 when the radar was operated in a meteor scatter mode. Momentum fluxes are derived from both the turbulent scatter and the meteor scatter measurements, but the techniques are quite different. Probability Distribution Functions are formed using turbulent scatter data. These show that wave packets sometimes have momentum flux magnitudes in excess of 100 m(2) s(-2). The technique for meteor radars, introduced by Hocking (2005), has been widely adopted by the radar community in recent years. The momentum flux estimated using this technique is found to be anti-correlated with the background tidal winds. A validation investigation is carried out for periods with a high meteor echo data rate. The conclusion was that the method can be used to calculate the sign of momentum flux, but does not accurately specify the magnitude. (C) 2016 The Authors. Published by Elsevier Ltd.

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  61. Relationship between solar wind dynamic pressure and amplitude of geomagnetic sudden commencement (SC) Reviewed

    Tohru Araki, Atsuki Shinbori

    EARTH PLANETS AND SPACE   Vol. 68 ( 1 )   2016.5

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    The local time variation of geomagnetic sudden commencements (SCs) has not been taken into account in the Siscoe's linear relationship which connects the SC amplitude with the corresponding dynamic pressure variation of the solar wind. By considering the physical background of SC, we studied which local time is best to extract the information of the solar wind dynamic pressure and concluded that the SC amplitude at 4-5 h local time of middle and low-latitude stations most directly reflects the dynamic pressure effect. This result is used to re-check the order of magnitude of the largest 3 SCs observed since 1868.

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  62. Simultaneous ground‐ and satellite‐based observation of MF/HF auroral radio emissions Reviewed

    Yuka Sato, Atsushi Kumamoto, Yuto Katoh, Atsuki Shinbori, Akira Kadokura, Yasunobu Ogawa

    Journal of Geophysical Research, Space Physics   Vol. 121   page: 4530 - 4541   2016.5

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  63. Prototype Development of the JavaFX-based iUgonet Data Analysis Software (JudasFX) Reviewed

    Yukinobu KOYAMA, Yuka SATO, Shinya NAKANO, Manabu YAGI, Yoshimasa TANAKA, Shuji ABE, Masahito NOSE, Kei KURAKAWA, Daisuke IKEDA, Norio UMEMURA, Atsuki SHINBORI, Satoru UeNo

    Journal of Space Science Informatics Japan   ( 第5号 )   2016.3

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  64. Response of the incompressible ionosphere to the compression of the magnetosphere during the geomagnetic sudden commencements Reviewed

    T. Kikuchi, K. K. Hashimoto, I. Tomizawa, Y. Ebihara, Y. Nishimura, T. Araki, A. Shinbori, B. Veenadhari, T. Tanaka, T. Nagatsuma

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 121 ( 2 ) page: 1536 - 1556   2016.2

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    The ionospheric plasma in midlatitude moves upward/downward during the geomagnetic sudden commencement causing the HF Doppler frequency changes; SCF (+-) and (-+) on the dayside and nightside, respectively, except for the SCF (+-) in the evening as found by Kikuchi et al. (1985). Although the preliminary and main frequency deviations (PFD, MFD) of the SCF have been attributed to the dusk-to-dawn and dawn-to-dusk potential electric fields, there still remain questions if the positive PFD can be caused by the compressional magnetohydrodynamic (MHD) wave and what causes the evening anomaly of the SCF. With the HF Doppler sounder, we show that the dayside ionosphere moves upward toward the Sun during the main impulse (MI) of the SC, when the compressional wave is supposed to push the ionosphere downward. The motion of the ionosphere is shown to be correlated with the equatorial electrojet, matching the potential electric field transmitted with the ionospheric currents from the polar ionosphere. We confirmed that the electric field of the compressional wave is severely suppressed by the conducting ionosphere and reproduced the SC electric fields using the global MHD simulation in which the potential solver is employed. The model calculations well reproduced the preliminary impulse and MI electric fields and their evening anomaly. It is suggested that the electric potential is transmitted from the polar ionosphere to the equator by the zeroth-order transverse magnetic (TM0) mode waves in the Earth-ionosphere waveguide. The near-instantaneous transmission of the electric potential leads to instantaneous global response of the incompressible ionosphere.

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  65. Measurement of momentum flux using two meteor radars in Indonesia Reviewed

    Naoki Matsumoto, Atsuki Shinbori, Dennis M. Riggin, Toshitaka Tsuda

    ANNALES GEOPHYSICAE   Vol. 34 ( 3 ) page: 369 - 377   2016

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    Two nearly identical meteor radars were operated at Koto Tabang (0.20 degrees S, 100.32 degrees E), West Sumatra, and Biak (1.17 degrees S, 136.10 degrees E), West Papua, in Indonesia, separated by approximately 4000 km in longitude on the Equator. The zonal and meridional momentum flux, u'w' and v'w', where u, v, and w are the eastward, northward, and vertical wind velocity components, respectively, were estimated at 86 to 94 km altitudes using the meteor radar data by applying a method proposed by Hocking (2005). The observed u'w' at the two sites agreed reasonably well at 86, 90, and 94 km during the observation periods when the data acquisition rate was sufficiently large enough. Variations in v'w' were consistent between 86, 90, and 94 km altitudes at both sites. The climatological variation in the monthly averaged u'w' and v'w' was investigated using the long-term radar data at Koto Tabang from November 2002 to November 2013. The seasonal variations in u'w' and v'w' showed a repeatable semiannual and annual cycles, respectively. u'w' showed eastward values in February-April and July-September and v'w' was northward in June to August at 90-94 km, both of which were generally anti-phase with the mean zonal and meridional winds, having the same periodicity. Our results suggest the usefulness of the Hocking method.

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  66. JavaFX-based iUgonet Data Analysis Software (JudasFX)のプロトタイプ開発 Reviewed

    小山 幸伸, 池田 大輔, 新堀 淳樹, 堀 智昭

    宇宙科学情報解析論文誌   Vol. 5   page: 81 - 92   2016

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  67. IMF-By dependence of transient ionospheric flow perturbation associated with sudden impulses: SuperDARN observations Reviewed

    Tomoaki Hori, Atsuki Shinbori, Shigeru Fujita, Nozomu Nishitani

    EARTH PLANETS AND SPACE   Vol. 67 ( 1 )   2015.11

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    A statistical study using a large dataset of Super Dual Auroral Radar Network (SuperDARN) observations is conducted for transient ionospheric plasma flows associated with sudden impulses (SI) recorded on ground magnetic field. The global structure of twin vortex-like ionospheric flows is found to be consistent with the twin vortices of ionospheric Hall current deduced by the past geomagnetic field observations. An interesting feature, which is focused on in this study, is that the flow structures show a dawn-dusk asymmetry depending on the combination of the polarity of SI and interplanetary magnetic field (IMF)-By. Detailed statistics of the SuperDARN observations reveal that the dawn-dusk asymmetry of flow vortices due to IMF-By appears during negative SIs, while such asymmetric characteristics are not seen during positive SIs. On the basis of the upstream observations, we suggest that this particular dawn-dusk asymmetry is caused by the interaction between the pre-existing round convection cell and a pair of the transient convection vortices associated with SIs.

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  68. Response of ionospheric electric fields at mid-low latitudes during sudden commencements Reviewed

    N. Takahashi, Y. Kasaba, A. Shinbori, Y. Nishimura, T. Kikuchi, Y. Ebihara, T. Nagatsuma

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 120 ( 6 ) page: 4849 - 4862   2015.6

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    Using in situ observations from the Republic of China Satellite-1 spacecraft, we investigated the time response and local time dependence of the ionospheric electric field at mid-low latitudes associated with geomagnetic sudden commencements (SCs) that occurred from 1999 to 2004. We found that the ionospheric electric field variation associated with SCs instantaneously responds to the preliminary impulse (PI) signature on the ground regardless of spacecraft local time. Our statistical analysis also supports the global instant transmission of electric field from the polar region. In contrast, the peak time detected in the ionospheric electric field is earlier than that of the equatorial geomagnetic field (similar to 20s before in the PI phase). Based on the ground-ionosphere waveguide model, this time lag can be attributed to the latitudinal difference of ionospheric conductivity. However, the local time distribution of the initial excursion of ionospheric electric field shows that dusk-to-dawn ionospheric electric fields develop during the PI phase. Moreover, the westward electric field in the ionosphere, which produces the preliminary reverse impulse of the geomagnetic field on the dayside feature, appears at 18-22h LT where the ionospheric conductivity beyond the duskside terminator (18h LT) is lower than on the dayside. The result of a magnetohydrodynamic simulation for an ideal SC shows that the electric potential distribution is asymmetric with respect to the noon-midnight meridian. This produces the local time distribution of ionospheric electric fields similar to the observed result, which can be explained by the divergence of the Hall current under nonuniform ionospheric conductivity.

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  69. The capacity-building and science-enabling activities of the IUGONET for the solar-terrestrial research community Reviewed

    Yatagai, A; Sato, Y; Shinbori, A; Abe, S; UeNo, S

    EARTH PLANETS AND SPACE   Vol. 67 ( 1 )   2015.1

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    Background: This paper presents an overview of the capacity-building activities and science-enabling services of the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) project. This Japanese program, which started in 2009, is building a metadata database (MDDB) of ground-based observations and is developing an analysis software to handle the data linked to the MDDB system for use by the solar-terrestrial physics community. Because the institutional members of the IUGONET are mainly universities in Japan, we explore tools that can contribute to advanced education as well as promote research activities. Findings: In this paper, we describe the utilities of the IUGONET for education, including our capacity-building activities in developing countries. We have regularly facilitated training seminars for Japanese students on the use of our tools (IUGONET MDDB and the software), and we have held capacity-building seminars for young scientists in developing countries. In addition to the MDDB, we have prepared various 'gateway' tools for users who are unfamiliar with 'keywords' to search for data. One of these is a geographical display tool that uses Google Earth (KML file), which is included as supplemental material to this paper. The usefulness of the IUGONET has been proven over its first 5 years of operation by the increasing number of its users, which has led to the production of approximately 500 scientific papers, including 42 thesis papers. Conclusions: The IUGONET community collaborates with the Scientific Committee on Solar-Terrestrial Physics program, not only in its scientific activities, but also in the establishment of E-infrastructure and capacity building.

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  70. Thermal and low-energy ion outflows in and through the polar cap: The polar wind and the low-energy component of the cleft ion fountain Reviewed

    Kitamura, N, K. Seki, Y. Nishimura, T. Abe, M. Yamada, S. Watanabe, A. Kumamoto, A. Shinbori, A. W. Yau

    AGU Geophysical Monograph     2015

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  71. Long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet daily variation Reviewed

    Shinbori, A; Koyama, Y; Nose, M; Hori, T; Otsuka, Y; Yatagai, A

    EARTH PLANETS AND SPACE   Vol. 66 ( 1 ) page: 1 - 20   2014.12

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    Characteristics of long-term variation in the amplitude of solar quiet (Sq) geomagnetic field daily variation have been investigated using 1-h geomagnetic field data obtained from 69 geomagnetic observation stations within the period of 1947 to 2013. The Sq amplitude observed at these geomagnetic stations showed a clear dependence on the 10- to 12-year solar activity cycle and tended to be enhanced during each solar maximum phase. The Sq amplitude was the smallest around the minimum of solar cycle 23/24 in 2008 to 2009. The relationship between the solar F10.7 index and Sq amplitude was approximately linear but about 53% of geomagnetic stations showed a weak nonlinear relation to the solar F10.7 index. In order to remove the effect of solar activity seen in the long-term variation of the Sq amplitude, we calculated a linear or second-order fitting curve between the solar F10.7 index and Sq amplitude during 1947 to 2013 and examined the residual Sq amplitude, which is defined as the deviation from the fitting curve. As a result, the majority of trends in the residual Sq amplitude that passed through a trend test showed negative values over a wide region. This tendency was relatively strong in Europe, India, the eastern part of Canada, and New Zealand. The relationship between the magnetic field intensity at 100-km altitude and residual Sq amplitude showed an anti-correlation for about 71% of the geomagnetic stations. Furthermore, the residual Sq amplitude at the equatorial station (Addis Ababa) was anti-correlated with the absolute value of the magnetic field inclination. This implies movement of the equatorial electrojet due to the secular variation of the ambient magnetic field.

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  72. An Interactive Data Language software package to calculate ionospheric conductivity by using numerical models Reviewed

    Yukinobu Koyamaa, Atsuki Shinbori, Yoshimasa Tanaka, Tomoaki Hori, Masahito Nose, Satoshi Oimatsu

    COMPUTER PHYSICS COMMUNICATIONS   Vol. 185 ( 12 ) page: 3398 - 3405   2014.12

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    The Inter-university Upper atmosphere Global Observation NETwork (IUGONET) project focuses on handling ground-based observational data of the upper atmosphere. To this end, the project members have been developing a data analysis software package which is based on Interactive Data Language (IDL). Filling the spatial gaps in observational data requires the use of numerical models. In this paper, we discuss an IDL software package for global ionospheric conductivity by integration of 3rd party numerical models. The model can be used to create further derived models. (C) 2014 Elsevier B.V. All rights reserved.

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  73. Long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet daily variation Reviewed

    Shinbori, A, Y. Koyama, M, Nose, T. Hori, Y. Otsuka, A. Yatagai

    Earth, Planets and Space   Vol. 65 ( 155 )   2014.12

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  74. The capacity-building and science-enabling activities of the IUGONET to the solar-terrestrial research community Reviewed

    Yatagai, A, Y. Sato, A. Shinbori, S. Abe, S. UeNo, IUGONET Team

    Earth, Planets and Space     2014.12

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  75. Interuniversity Upper Atmosphere Global Observation NETwork (IUGONET) meta-database and analysis software Reviewed

    A. Yatagai, Y. Tanaka, S. Abe, A. Shinbori, M. Yagi, S. UeNo, Y. Koyama, N. Umemura, M. Nosé, T. Hori, Y. Sato, N. O. Hashiguchi, N. Kaneda

    Data Science Journal   Vol. 13 ( 0 ) page: PDA37 - PDA43   2014.10

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    An overview of the Interuniversity Upper atmosphere Global Observation NETwork (IUGONET) project is presented. This Japanese program is building a meta-database for ground-based observations of the upper atmosphere, in which metadata connected with various atmospheric radars and photometers, including those located in both polar regions, are archived. By querying the metadata database, researchers are able to access data file/information held by data facilities. Moreover, by utilizing our analysis software, users can download, visualize, and analyze upper-atmospheric data archived in or linked with the system. As a future development, we are looking to make our database interoperable with others.

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  76. Progress of the IUGONET system - metadata database for upper atmosphere ground-based observation data Reviewed

    Shuji Abe, Norio Umemura, Yukinobu Koyama, Yoshimasa Tanaka, Manabu Yagi, Akiyo Yatagai, Atsuki Shinbori, Satoru UeNo, Yuka Sato, Naoki Kaneda

    EARTH PLANETS AND SPACE   Vol. 66 ( 133 )   2014.10

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    Background: The Interuniversity Upper atmosphere Global Observation NETwork (IUGONET) project is a 6-year research project which started in 2009. The objective of this project is to establish a metadata database of various ground-based observation data covering a wide region from the Sun to the Earth; this will encourage more studies on the mechanisms of long-term variations in the upper atmosphere.
    Findings: For archiving purposes, the metadata database system for cross-searching various data distributed across many universities and institute was developed based on the existing repository software called DSpace as the core component and the Space Physics Archive Search and Extract (SPASE) data model as the metadata format. The IUGONET metadata database is still in operation since it was released in March 2012. The system is continuously examined, tested, and updated to improve its quality. The OpenSearch interface in the IUGONET metadata database allows the user to use external applications easily for exchanging metadata and/or for analyzing data.
    Conclusions: We conducted self-examination of our product, which was added for planning future directions of the IUGONET project.

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  77. Application of associative search to the metadata database of the upper atmosphere Reviewed

    KOYAMA Yukinori, ABE Shuji, YAGI Manabu, UMEMURA Norio, HORI Tomoaki, SHINBORI Atsuki, SATO Yuka, IYEMORI Toshihiko, TANAKA Yoshimasa, HASHIGUCHI Noriko, UENO Satoru, YATAGAI Akiyo

    JAXA research and development report   Vol. 13   page: 89 - 97   2014.3

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    In order to understand the mechanism of global-scale phenomena in the upper atmosphere, multidisciplinary researches using many kinds of data are important. An infrastructure to access to many kinds of data on the Internet is one of the keys to the multidisciplinary researches. The Inter-university Upper atmosphere Global Observation NETwork (IUGONET) project solved this problem by developing a metadata database to provide information such as URL of database or each data .le, which are managed dispersively by several institutes. Because the metadata database covers a wide scienti.c .eld, it is likely that non-specialized users can not easily select a right search phrase. We connected an associative search engine which is called GETAssoc with the metadata database, in order to get the related words and to generate re-query phrases by using them automatically. We collected metadata from SAO/NASA Astrophysics Data System to create the dictionary for associative search. We show that the prepared dictionary gives the related terms as expected for generating re-query phrases.

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  78. Analysis software for upper atmospheric data developed by the IUGONET project and its application to polar science Reviewed

    Tanaka, Y.-M, A. Shinbori, T. Hori, Y. Koyama, S. Abe, N. Umemura, Y. Sato, M. Yagi, S. UeNo, A. Yatagai, Y. Ogawa, Y. Miyoshi

    Advances in Polar Science, 24, 231-240, doi:10.3724/SP.J.1085.2013.00231     2013.12

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  79. Global distributions of storm-time ionospheric currents as seen in geomagnetic field variations Reviewed

    Shinbori, A, T. Hori, Y. Tanaka, Y. Koyama, T. Kikuchi, T. Nagatsuma

    Advances in Polar Science, 24, 296-314, doi:10.3724/SP.J.1085.2013.00296   Vol. 24   page: 296 - 314   2013.12

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  80. Inter-university upper atmosphere global observation network (IUGONET) Reviewed

    Hayashi H., Koyama Y., Hori T., Tanaka Y., Abe S., Shinbori A., Kagitani M., Kouno T., Yoshida D., UeNo S., Kaneda N., Yoneda M., Umemura N., Tadokoro H., Motoba T.

    Data Science Journal   Vol. 12   2013.4

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    An overview of the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) project is presented with a brief description of the products to be developed. This is a Japanese inter-university research program to build the metadata database for ground-based observations of the upper atmosphere. The project also develops the software to analyze the observational data provided by various universities/institutes. These products will be of great help to researchers in efficiently finding, obtaining, and utilizing various data dispersed across the universities/institutes. This is expected to contribute significantly to the promotion of interdisciplinary research, leading to more a comprehensive understanding of the upper atmosphere.

    DOI: 10.2481/dsj.WDS-030

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  81. Inter-university upper atmosphere global observation network (IUGONET) Reviewed

    H. Hayashi, Y. Koyama, T. Hori, Y. Tanaka, S. Abe, A. Shinbori, M. Kagitani, T. Kouno, D. Yoshida, S. UeNo, N. Kaneda, M. Yoneda, N. Umemura, H. Tadokoro, T. Motoba

    Data Science Journal   Vol. 12   page: WDS179 - WDS184   2013.4

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    An overview of the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) project is presented with a brief description of the products to be developed. This is a Japanese inter-university research program to build the metadata database for ground-based observations of the upper atmosphere. The project also develops the software to analyze the observational data provided by various universities/institutes. These products will be of great help to researchers in efficiently finding, obtaining, and utilizing various data dispersed across the universities/institutes. This is expected to contribute significantly to the promotion of interdisciplinary research, leading to more a comprehensive understanding of the upper atmosphere.

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  82. IUGONETメタデータ登録・管理システムの処理性能評価 Reviewed

    堀智昭, 梅村宜生, 阿部修司, 小山幸伸, 田中良昌, 林寛生, 林寛生, 上野悟, 新堀淳樹, 佐藤由佳, 八木学

    宇宙航空研究開発機構研究開発報告 JAXA-RR-   ( 12-006 ) page: 71 - 78   2013.3

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  83. Performance study of IUGONET metadata management system Reviewed

    HORI Tomoaki, UEMURA Norio, ABE Shuji, KOYAMA Yukinobu, TANAKA Yoshimasa, HAYASHI Hiroo, UENO Satoru, SHINBORI Atsuki, SATO Yuka, YAGI Manabu

    JAXA research and development report   Vol. 12   page: 71 - 78   2013.3

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    This paper reports on the benchmark test of the metadata management system developed by the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) project. The IUGONET metadata management system consists of the metadata reception module based on file repositories of Git, which is a widely-used version control software, and the metadata import module to register metadata to the metadata database using the DSpace commands. We made the performance assessments for these two modules in terms of the processing speed for registering/importing metadata both on a native Linux platform and a virtualized Linux platform. As a result, the metadata reception module processes properly eve millions of registered metadata within several minutes at most, showing roughly the similar performance for the native and virtualized platform. On the other hand, the metadata import module needs much longer processing times of several to a few tens of hours for the same amount of metadata. As compared with the virtualized platform, the native platform gives a four times faster speed for updating indices for the built-in search engine based on Lucene. From a perspective of the regular operation of the metadata management system, the metadata import module runs more efficiently on the native Linux platform and it is estimated by our performance test that it takes about 5 hours to newly import 105 metadata files and subsequently takes about 21 hours to update the Lucene indices for the registered metadata of 5 × 106 in total.

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  84. Current status and future development of IUGONET data analysis software Reviewed

    Tanaka Yoshimasa, Shinbori Atsuki, Umemura Norio, Hori Tomoaki, Abe Shuji, Koyama Yukinobu, Hayashi Hiroo, Ueno Satoru, Sato Yuka, Yatagai Akiyo, Ogawa Yasunobu, Miyoshi Yoshizumi, Seki Kanako, Miyashita Yukinaga, Segawa Tomonori

    JAXA research and development report   Vol. 12   page: 63 - 70   2013.3

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    In the IUGONET (Inter-university Upper atmosphere Global Observation NETwork) project, we have developed UDAS (iUgonet Data Analysis Software), which is a software to visualize and analyze various kinds of upper atmospheric data distributed by five universities/institutes (Tohoku Univ., Nagoya Univ., Kyoto Univ., Kyushu Univ., and NIPR). UDAS is a plug-in software of TDAS (THEMIS Data Analysis Software suite) written in IDL (Interactive Data Language), and thus can call useful routines to visualize and analyze time series data and GUI included in TDAS. We released a beta version of UDAS at the IUGONET website in May, 2011, and a formal version in February, 2012. We are planning to incorporate UDAS into TDAS and release it from the THEMIS software website after September, 2012. Automatic test tools for the UDAS programs were developed to reduce the workload for the development team. Furthermore, we built an executable file of TDAS that can run on the IDL Virtual Machine environment without any IDL licenses and released it for public testing. These developments will contribute to the promotion of the use of the UDAS and the ground-based observational data distributed by the IUGONET institutions.

  85. Current status and future development of IUGONET data analysis software Reviewed

    Tanaka Yoshimasa, Shinbori Atsuki, Umemura Norio, Hori Tomoaki, Abe Shuji, Koyama Yukinobu, Hayashi Hiroo, Ueno Satoru, Sato Yuka, Yatagai Akiyo, Ogawa Yasunobu, Miyoshi Yoshizumi, Seki Kanako, Miyashita Yukinaga, Segawa Tomonori

    JAXA research and development report   Vol. 12 ( 12-006 ) page: 63 - 70   2013.3

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    In the IUGONET (Inter-university Upper atmosphere Global Observation NETwork) project, we have developed UDAS (iUgonet Data Analysis Software), which is a software to visualize and analyze various kinds of upper atmospheric data distributed by five universities/institutes (Tohoku Univ., Nagoya Univ., Kyoto Univ., Kyushu Univ., and NIPR). UDAS is a plug-in software of TDAS (THEMIS Data Analysis Software suite) written in IDL (Interactive Data Language), and thus can call useful routines to visualize and analyze time series data and GUI included in TDAS. We released a beta version of UDAS at the IUGONET website in May, 2011, and a formal version in February, 2012. We are planning to incorporate UDAS into TDAS and release it from the THEMIS software website after September, 2012. Automatic test tools for the UDAS programs were developed to reduce the workload for the development team. Furthermore, we built an executable file of TDAS that can run on the IDL Virtual Machine environment without any IDL licenses and released it for public testing. These developments will contribute to the promotion of the use of the UDAS and the ground-based observational data distributed by the IUGONET institutions.

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  86. Inter-University upper Atmosphere Global Observation Network (IUGONET) Reviewed

    Hayashi H., UeNo S., Kaneda N., Yoneda M., Umemura N., Tadokoro H., Motoba T., team IUGONET project, Koyama Y., Hori T., Tanaka Y., Abe S., Shinbori A., Kagitani M., Kouno T., Yoshida D.

    Data Science Journal   Vol. 12 ( 0 ) page: WDS179 - WDS184   2013

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    An overview of the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) project is presented with a brief description of the products to be developed. This is a Japanese inter-university research program to build the metadata database for ground-based observations of the upper atmosphere. The project also develops the software to analyze the observational data provided by various universities/institutes. These products will be of great help to researchers in efficiently finding, obtaining, and utilizing various data dispersed across the universities/institutes. This is expected to contribute significantly to the promotion of interdisciplinary research, leading to more a comprehensive understanding of the upper atmosphere.

    DOI: 10.2481/dsj.WDS-030

  87. IUGONET解析ソフトウェアの現状と今後の発展 Reviewed

    田中良昌, 新堀淳樹, 梅村宜生, 堀智昭, 阿部修司, 小山幸伸, 林寛生, 上野悟, 佐藤由佳, 谷田貝亜紀代, 小川泰信, 三好由純, 関華奈子, 宮下幸長, 瀨川朋紀

    宇宙科学情報解析論文誌   Vol. 2   page: 63 - 70   2013

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  88. Application of the associative searching system GETAssoc to the metadata database of the upper atmosphere

    Manabu YAGI, Yukinobu KOYAMA, Shuji ABE, Norio UMEMURA, Atsuki SHINBORI, Tomoaki HORI, Yoshimasa TANAKA, Satoru UeNo, Yuka SATO, Akiyo YATAGAI, and Ber, RITSCHEL

    Proceedings of Forum on Data Engineering and Information Management     page: A10-1   2013

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  89. Evolution of negative SI-induced ionospheric flows observed by SuperDARN King Salmon HF radar Reviewed

    T. Hori, A. Shinbori, N. Nishitani, T. Kikuchi, S. Fujita, T. Nagatsuma, O. Troshichev, K. Yumoto, A. Moiseyev, K. Seki

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 117 ( 12 )   2012.12

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    The spatial evolution of vortex-like flow structures induced by a negative sudden impulse (SI-) is studied on the basis of SuperDARN King Salmon HF radar (KSR) with other ground and satellite data. A large dip in the solar wind density induced a fairly large SI- with a SYM-H amplitude of similar to 40 nT. The SI- induced ionospheric flow signatures in the evening sector (MLT similar to 19 h) were observed by KSR as a westward flow associated with the preliminary impulse (PI) followed by a more intense eastward flow with the main impulse (MI) in the sub-auroral region of the magnetic latitude similar to 60-70 deg, consistent with the local ground magnetic field observations. Following the first PI-MI flow sequence, KSR saw a second and possibly third sequence of flow variation which were much smaller in flow amplitude than the first pair but showed qualitatively very similar flow variations and latitudinal/longitudinal propagation characteristics. These observations can be interpreted as aftershocks of the first PI-MI; the same sequence of vortices and field-aligned currents were generated and then drifted anti-sunward with the same mechanism, namely the pumping motion of the dayside magnetosphere. These results are qualitatively consistent with predictions suggested by recent numerical simulations. Citation: Hori, T., A. Shinbori, N. Nishitani, T. Kikuchi, S. Fujita, T. Nagatsuma, O. Troshichev, K. Yumoto, A. Moiseyev, and K. Seki (2012), Evolution of negative SI- induced ionospheric flows observed by SuperDARN King Salmon HF radar, J. Geophys. Res., 117, A12223, doi:10.1029/2012JA018093.

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  90. Storm-time electron density enhancement in the cleft ion fountain Reviewed

    N. Kitamura, Y. Nishimura, M. O. Chandler, T. E. Moore, N. Terada, T. Ono, A. Shinbori, A. Kumamoto

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 117 ( 11 )   2012.11

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    To determine the characteristics and origin of observed storm-time electron density enhancements in the polar cap, and to investigate the spatial extent (noon-midnight direction) of associated O+ ion outflows, we analyzed nearly simultaneous observations of such electron density enhancements from the Akebono satellite and ion upflows from the Polar satellite during a geomagnetic storm occurring on 6 April 2000. The Akebono satellite observed substantial electron density enhancements by a factor of similar to 10-90 with a long duration of similar to 15 h at similar to 2 R-E in the southern polar region. The Polar satellite outflow measurements in the northern polar cap at similar to 7-4 R-E exhibited velocity filtering of the similar to 100 eV to similar to 0 eV (from the spacecraft potential) ion outflow from the cleft ion fountain, with resultant temperatures declining from similar to 3 eV to 0.03 eV with increasing distance from the cusp. Similar velocity filtering was detected in the southern polar cap at similar to 1.8-3.5 RE. The region of O+ ion outflows with fluxes exceeding 5 x 10(8) /cm(2)/s (mapped to 1000 km altitude) extended similar to 10 degrees MLAT (similar to 1000 km) at the ionosphere from the cusp/cleft into the dayside polar cap at similar to 2.5 RE. These coordinated Akebono-Polar observations are consistent with the development of storm-time electron density enhancements in the polar cap as a result of the bulk outflow of low-energy plasma as part of the cleft ion fountain. The large spatial scale, large ion fluxes, and the long duration indicate significant supply of very-low-energy O+ ions to the magnetosphere through this region.

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  91. Magnetic local time and latitude dependence of amplitude of the main impulse (MI) of geomagnetic sudden commencements and its seasonal variation Reviewed

    Atsuki Shinbori, Yuji Tsuji, Takashi Kikuchi, Tohru Araki, Akihiro Ikeda, Teiji Uozumi, Dmitry Baishev, Boris M. Shevtsov, Tsutomu Nagatsuma, Kiyohumi Yumoto

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 117 ( 8 )   2012.8

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    The magnetic local time and latitude dependence of amplitude of the main impulse (MI) of geomagnetic sudden commencements (SCs) and its seasonal variation have been investigated using high time resolution (1-3 sec) geomagnetic data in the latitudinal range 27-70 degrees for the period 1996-2010. The daytime distribution of the SC-MI amplitude in the sub-auroral and middle latitudes (35-60 degrees) is similar to the DP-2 type geomagnetic variation which shows negative and positive changes in the morning and afternoon, respectively. The magnetic field variation is reversed around the magnetic latitude of 63-65 degrees. This suggests that a pair of field-aligned currents (FACs), resembling the region-1 (R-1) FACs, is located near the magnetic latitude of 63-65 degrees. The nighttime SC amplitude is enhanced significantly in the low and middle latitudes (27-60 degrees). The enhancement is due to the magnetic effect produced by the SC-MI FACs. In the nighttime auroral latitude (63-65 degrees), the SC amplitude decreases steeply due to the enhanced westward auroral electrojet associated with the compression of the magnetosphere. The size of the diurnal variation tends to increase significantly during the summer, compared with that during the winter. This seasonal variation suggests that the DP-2 type ionospheric currents (ICs) and FACs generated during the SC-MI phase are intensified by increased ionospheric conductivities during the summer. It can be concluded that the large-scale MI current system in the ionosphere and magnetosphere is voltage generator.

    DOI: 10.1029/2012JA018006

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  92. Magnetic latitude and local time distributions of ionospheric currents during a geomagnetic storm Reviewed

    Yuji Tsuji, Atsuki Shinbori, Takashi Kikuchi, Tsutomu Nagatsuma

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 117 ( 7 )   2012.7

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    In order to clarify the global distribution of ionospheric currents during a geomagnetic storm, we analyzed ground magnetic disturbances from high latitudes to the magnetic equator for the storm on September 7-8, 2002, with the minimum SYM-H value of -168 nT. In this analysis, we investigated magnetic field deviations in the northward component from the SYM-H, as functions of the dipole magnetic latitude (DMLAT) and the magnetic local time (MLT). During the main phase of the storm, the deviations at the low latitudes (10 degrees-35 degrees in DMLAT) were positive/negative in the dawn/dusk (0-9/11-24 h MLT) sector. On the other hand, the deviations at the dayside middle latitudes (35 degrees-55 degrees in DMLAT) were negative/positive in the morning/afternoon (6-12/13-15 h MLT) sector. The local time distribution at the low latitudes may represent the dawn-dusk asymmetry of the storm time ring current, while that at the dayside middle latitudes coincides with the DP2 currents due to the convection electric field associated with the Region 1 field-aligned currents (R1 FACs). All over the nightside middle latitude, the deviations were positive. This implies the direct effect of the R1 FACs through the Biot-Savart's law. At the geomagnetic equator, the eastward and westward electrojets were intensified on the day and nightside, respectively, being caused by the penetrated dawn-to-dusk convection electric field. We found that the MLT distribution of the magnetic deviations during the recovery phase was in opposite sense to that during the main phase at the dayside middle latitudes. The reversed magnetic disturbances must be due to the overshielding electric field associated with the Region 2 field-aligned currents (R2 FACs). Similarly, the deviations at the dayside and nightside equator were reversed, indicating penetration of the dusk-to-dawn overshielding electric field into the equatorial ionosphere. Based on the above results, we propose a current system including the ionospheric currents at middle latitudes caused by the R1/R2 FACs, equatorial EEJ/CEJ, and asymmetric ring current, during the main/recovery phase of the geomagnetic storm.

    DOI: 10.1029/2012JA017566

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  93. Development of IUGONET data analysis software Reviewed

    田中良昌, 新堀淳樹, 鍵谷将人, 堀智昭, 阿部修司, 小山幸伸, 林寛生, 吉田大紀, 河野貴久, 上野悟, 金田直樹, 米田瑞生, 田所裕康, 元場哲郎, 三好由純, 関華奈子, 宮下幸長, 瀬川朋紀, 小川泰信

    宇宙航空研究開発機構研究開発報告 JAXA-RR-   ( 11-007 ) page: 91 - 98   2012.3

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  94. IUGONET共通メタデータフォーマットの策定とメタデータ登録管理システムの開発 Reviewed

    堀智昭, 鍵谷将人, 田中良昌, 林寛生, 上野悟, 吉田大紀, 阿部修司, 小山幸伸, 河野貴久, 金田直樹, 新堀淳樹, 田所裕康, 米田瑞生

    宇宙航空研究開発機構研究開発報告 JAXA-RR-   ( 11-007 ) page: 105 - 111   2012.3

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  95. 超高層物理学分野の為のメタデータ・データベースの開発 Reviewed

    小山幸伸, 河野貴久, 堀智昭, 阿部修, 吉田大紀, 林寛生, 田中良昌, 新堀淳樹, 上野悟, 金田直樹, 米田瑞生, 元場哲郎, 鍵谷将人, 田所裕康

    宇宙航空研究開発機構研究開発報告 JAXA-RR-   ( 11-007 ) page: 99 - 104   2012.3

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  96. 大学間連携プロジェクト「超高層大気長期変動の全球地上ネットワーク観測・研究」 Reviewed

    林寛生, 小山幸伸, 堀智昭, 田中良昌, 新堀淳樹, 鍵谷将人, 阿部修司, 河野貴久, 吉田大紀, 上野悟, 金田直樹, 米田瑞生, 田所裕康, 元場哲郎

    宇宙航空研究開発機構研究開発報告 JAXA-RR-   ( 11-007 ) page: 113 - 120   2012.3

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  97. Metadata Database Development for Upper Atmosphere Reviewed

    KOYAMA Yukinobu, KOUNO Takahisa, HORI Tomoaki, ABE Shuji, YOSHIDA Daiki, HAYASHI Hiroo, TANAKA Yoshimasa, SHINBORI Atsuki, UENO Satoru, KANEDA Naoki, YONEDA Mizuki, MOTOBA Tetsuro, KAGITANI Masato, TADOKORO Hiroyasu

    JAXA research and development report   Vol. 11   page: 99 - 104   2012.3

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    We have been building the metadata database of the gound-based observational data for upper atmosphere as developers of the Inter-university Uppear atmosphere Global Observation NETwork (IUGONET) project which is a six year research project from fiscal 2009 by the five Japanese universities and institutes. The main purpose of the metadata database to facilitate access is the improvement of accessibility to the various kinds of the observational data which are distributed to many databases in the various institutes. We designed the IUGONET common metadata format which is based on the SPASE data model/metadata format developed by the SPASE Consortium. Then we customized DSpace, a free repository software, which handles the Dublin Core metadata format by default, to handle the IUGONET common metadata. In this paper, we describe the IUGONET metadata database as a case example of metadata database adaptation for geoscience.

  98. Design of IUGONET metadata format and development of metadata management system (Journal of Space Science Informatics Japan No.1) Reviewed

    HORI Tomoaki, KAGITANI Masato, TANAKA Yoshimasa, HAYASHI Hiroo, UeNo Satoru, YOSHIDA Daiki, ABE Shuji, KOYAMA Yukinobu, KOUNO Takahisa, KANEDA Naoki, SHINBORI Atsuki, TADOKORO Hiroyasu, YONEDA Mizuki

    JAXA research and development report   Vol. 11   page: 105 - 111   2012.3

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    This paper reports on the common metadata format and the metadata management system developed by the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) project. The IUGONET common metadata format has been designed on the basis of the Space Physics Archive Search and Extract (SPASE) data model/metadata format, which has been developed by the SPASE consortium, with some modifications made by IUGONET to accommodate metadata for the various kinds of ground observational data produced by the IUGONET institutes and universities. We have also developed the registration/management system for metadata XML files using GIT, which is a widely-used version control software. With the designed metadata format and the metadata management system, IUGONET continues to generate and archive metadata for the observational data of Japanese Solar-Terrestrial physics community.

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  99. Development of IUGONET data analysis software (Journal of Space Science Informatics Japan No.1) Reviewed

    TANAKA Yoshimasa, SHINBORI Atsuki, KAGITANI Masato, HORI Tomoaki, ABE Shuji, KOYAMA Yukinobu, HAYASHI Hiroo, YOSHIDA Daiki, KONO Takahisa, UeNo Satoru, KANEDA Naoki, YONEDA Mizuki, TADOKORO Hiroyasu, MOTOBA Tetsuo, MIYOSHI Yoshizumi, SEKI Kanako, MIYASHITA Yukinaga, SEGAWA Tomonori, OGAWA Yasunobu

    JAXA research and development report   Vol. 11   page: 91 - 98   2012.3

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    In this paper we report an outline of data analysis software developed by the IUGONET (Inter-university Upper atmosphere Global Observation NETwork) project. UDAS (iUgonet Data Analysis Software) is the software to visualize and analyze the upper atmospheric data distributed by five universities/institutes (Tohoku Univ., Nagoya Univ., Kyoto Univ., Kyushu Univ., and NIPR) that belong to the IUGONET project. The UDAS is a plug-in software of TDAS (THEMIS Data Analysis Software suite) that is written in IDL (Interactive Data Language) and has many useful routines to visualize and analyze time series data. In addition, the UDAS provides the GUI (Graphical User Interface) for beginners of IDL. A beta version of the UDAS was released at the IUGONET website in May, 2011. Furthermore, future perspectives of the UDAS are described.

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  100. Inter-university Upper atmosphere Global Observation NETwork (IUGONET) project (Journal of Space Science Informatics Japan No.1) Reviewed

    HAYASHI Hiroo, KOYAMA Yukinobu, HORI Tomoaki, TANAKA Yoshimasa, SHINBORI Atsuki, KAGITANI Masato, ABE Shuji, KOUNO Takahisa, YOSHIDA Daiki, UeNo Satoru, KANEDA Naoki, YONEDA Mizuki, TADOKORO Hiroyasu, MOTOBA Tetsuo

    JAXA research and development report   Vol. 11   page: 113 - 120   2012.3

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    This paper describes an overview of the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) project and briefly mentions important products to be developed in the project. It is an inter-university program by the National Institute of Polar Research, Tohoku University, Nagoya University, Kyoto University, and Kyushu University to build a database of metadata for ground-based observations of the upper atmosphere. The metadata database will be of great help to researchers in efficiently finding and obtaining observational data spread over the universities and institutes. This should also facilitate synthetic analysis of multi-disciplinary data, which will lead to new types of research in the upper atmosphere. The IUGONET development team designs its metadata format based on the SPASE (Space Physics Archive Search and Extract) data model. Some modifications depending on characteristics of ground-based observations of the upper atmosphere are added. The metadata database system is built on the platform of DSpace with customizations according to the IUGONET metadata. In addition, an analysis software for the observational data provided by the IUGONET institutions is developed based on the TDAS (THEMIS Data Analysis Software suite) library written in IDL (Interactive Data Language).

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  101. Effect of R2-FAC development on the ionospheric electric field pattern deduced by a global ionospheric potential solver Reviewed

    Nakamizo, A. Y. Hiraki, Y. Ebihara, T. Kikuchi, K. Seki, T. Hori, A. Ieda, Y. Miyoshi, Y. Tsuji, Y. Nishimura, A. Shinbori

    Journal of Geophysical Research, Volume 117, Issue A9, CiteID: A09231, doi: 10.1029/2012JA017669   Vol. 117 ( 9 )   2012

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    Toward the understanding of the effect of the magnetosphere originated disturbances on the global ionospheric electric field and current system, we developed a two-dimensional ionospheric potential solver based on the so-called "thin shell model." The important extension from the previous studies is that our model covers the pole-to-pole ionosphere without placing any boundary at the equator. By using this solver, we investigate how the ionospheric electric field changes from undershielding condition to overshielding condition as the field aligned current (FAC) distribution changes. Calculations are performed by changing IR2/IR1 (the ratio of current intensities of region 2 (R2) and region 1 (R1) FACs) and by moving R2-FAC relative to the fixed R1-FAC. The results are summarized as follows: (1) The turning point, at which the ionosphere turns from undershielding to overshielding is IR2/IR1 = 0.7 ∼ 0.8. (2) With increasing the local time deference between the R1 and R2-FAC peaks, the efficiency of the shielding by R2-FAC increases but the associated potential skews to the nightside. (3) At the same time the shielding effect is weakened around noon, where the R1-potential intrudes to the low latitude region instead, but the R2-potential remains dominant at other local times. The result suggests that the overshielding or undershielding should be identified by observations not only in a limited local time sector but also in the overall ionosphere as much as possible. In order to accurately describe the ionospheric condition, we suggest new classification terms, "complete-overshielding" and "incomplete-overshielding. " © 2012. American Geophysical Union. All Rights Reserved.

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  102. 超高層物理学のための分野横断型メタデータ・データベースの構築

    梅村宜生, 小山幸伸, 堀智昭, 阿部修司, 林寛生, 新堀淳樹, 田中良昌, 上野悟, 米田瑞生, 金田直樹, 元場哲郎

    第4回データ工学と情報マネジメントに関するフォーラム論文集     page: A7-1   2012

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  103. Solar zenith angle dependence of plasma density and temperature in the polar cap ionosphere and low-altitude magnetosphere during geomagnetically quiet periods at solar maximum Reviewed

    N. Kitamura, Y. Ogawa, Y. Nishimura, N. Terada, T. Ono, A. Shinbori, A. Kumamoto, V. Truhlik, J. Smilauer

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 116 ( 8 )   2011.8

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    We constructed an empirical model of the electron density profile with solar zenith angle (SZA) dependence in the polar cap during geomagnetically quiet periods using 63 months of Akebono satellite observations at solar maximum. The electron density profile exhibits a transition at similar to 2000 km altitude only under dark conditions. The electron density and scale height at low altitudes change drastically, by factors of 25 (at 2300 km altitude) and 2.0, respectively, as the SZA increases from 90 degrees to 120 degrees. The SZA dependence of the ion and electron temperatures is also investigated statistically on the basis of data obtained by the Intercosmos satellites and European Incoherent Scatter (EISCAT) Svalbard radar (ESR). A drastic change in the electron temperature occurs near the terminator, similarly to that in the electron density profile obtained by the Akebono satellite. The sum of the ion and electron temperatures obtained by the ESR (similar to 6500 K at similar to 1050 km altitude under sunlit conditions and similar to 3000 K at similar to 750 km altitude under dark conditions) agrees well with the scale height at low altitudes obtained from the Akebono observations, assuming that the temperature is constant and that O(+) ions are dominant. Comparisons between the present statistical results (SZA dependence of the electron density and ion and electron temperatures) and modeling studies of the polar wind indicate that the plasma density profile (especially of the O(+) ion density) in the polar cap is strongly controlled by solar radiation onto the ionosphere by changing ion and electron temperatures in the ionosphere during geomagnetically quiet periods.

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  104. Penetration of Magnetospheric Electric Fields to the Low Latitude Ionosphere During Storm/Substorms Reviewed

    Kikuchi, T, K. K. Hashimoto, A. Shinbori, Y. Tsuji, S. Watari

    Aeronomy of the Earth's Atmosphere and Ionosphere IAGA Special Sopron Book Series 2, DOI: 10.1007/978-94-007-0326-1_34, Edit. M.A. Abdu, D.Pancheva, A. Bhattacharyya, Springer Science+Business Media B.V.   Vol. 2   page: 443 - 453   2011.2

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  105. Penetration of Magnetospheric Electric Fields to the Low Latitude Ionosphere During Storm/Substorms Reviewed

    Kikuchi, T; Hashimoto, KK; Shinbori, A; Tsuji, Y; Watari, SI

    AERONOMY OF THE EARTH'S ATMOSPHERE AND IONOSPHERE   Vol. 2   page: 443 - 453   2011

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    DOI: 10.1007/978-94-007-0326-1_34

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  106. Direct measurements of the Poynting flux associated with convection electric fields in the magnetosphere Reviewed

    Y. Nishimura, T. Kikuchi, A. Shinbori, J. Wygant, Y. Tsuji, T. Hori, T. Ono, S. Fujita, T. Tanaka

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 115 ( 12 )   2010.12

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    Observations of Poynting fluxes associated with onset of convection electric fields are essential for understanding of electromagnetic energy transport from the solar wind toward the magnetosphere leading to changes in the convection electric field, which is one of the most fundamental parameters in the magnetosphere-ionosphere coupled system. We present Cluster multispacecraft observations of Poynting fluxes associated with abrupt changes in large-scale electric fields during sudden commencements and southward turning of the interplanetary magnetic field (IMF). The Cluster spacecraft detected Poynting fluxes dominated by the field-aligned upward component during the preliminary impulse of sudden commencements and in the initial period after southward turning of the IMF. The upward Poynting flux indicates existence of Alfven waves transporting electromagnetic energy from the ionosphere toward the magnetosphere leading to magnetospheric convection changes. The waveguide model and global magnetohydrodynamic (MHD) simulation calculating evolution of the Poynting flux following solar wind pressure enhancements also show upward Poynting fluxes propagating from the ionosphere toward the magnetosphere faster than the propagation of compressional waves. We conclude that the ionosphere acts as a channel to transmit electromagnetic energy supplied as field-aligned currents toward a wide region in the magnetosphere-ionosphere system instantaneously, leading to changes in magnetospheric convection electric fields.

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  107. Observations of very-low-energy (&lt; 10 eV) ion outflows dominated by O+ ions in the region of enhanced electron density in the polar cap magnetosphere during geomagnetic storms Reviewed

    N. Kitamura, Y. Nishimura, T. Ono, Y. Ebihara, N. Terada, A. Shinbori, A. Kumamoto, T. Abe, M. Yamada, S. Watanabe, A. Matsuoka, A. W. Yau

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 115 ( 11 )   2010.11

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    Velocity distributions of upflowing ions in the polar ionosphere are crucial to understand their destinations. Natural plasma wave observations by the plasma wave and sounder experiments and thermal ion observations by the suprathermal ion mass spectrometer onboard the Akebono satellite at similar to 9000 km altitude in the polar magnetosphere during the geomagnetic storms showed that ions in the region of enhanced electron density in the polar cap were dominated by very-low-energy O+ ions (similar to 85%) with upward velocities of 4-10 km s(-1), corresponding to streaming energies of 1.3-8.4 eV. The fluxes of very-low-energy upflowing O+ ions exceeded 1 x 10(9) cm(-2) s(-1) (mapped to 1000 km altitude) across wide regions. These signatures are consistent with high-density plasma supplied by the cleft ion fountain mechanism. Trajectory calculations of O+ ions based on the Akebono observations as the initial condition showed the transport paths and accelerations of the O+ ions and indicated that the velocities of the very-low-energy upflowing O+ ions through the dayside polar cap are enough to reach the magnetosphere under strong convection. The calculations suggest the importance of the very-low-energy upflowing O+ ions with large fluxes in the total O+ ion supply toward the magnetosphere, especially the near-Earth tail region and inner magnetosphere. The initially very-low-energy O+ ions can contribute significantly to the ring current formation during geomagnetic storms since some of the O+ ions were transported into the ring current region with typical energies of ring current ions (several tens of keV) in the trajectory calculations.

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  108. Anomalous occurrence features of the preliminary impulse of geomagnetic sudden commencement in the South Atlantic Anomaly region Reviewed

    Atsuki Shinbori, Yukitoshi Nishimura, Yuji Tsuji, Takashi Kikuchi, Tohru Araki, Akihiro Ikeda, Teiji Uozumi, Roland E. S. Otadoy, Hisashi Utada, Jose Ishitsuka, Nalin Baual Trivedi, Severino L. G. Dutra, Nelson Jorge Schuch, Shinichi Watari, Tsutomu Nagatsuma, Kiyohumi Yumoto

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 115 ( 8 )   2010.8

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    Occurrence features of the preliminary impulse (PI) of geomagnetic sudden commencement (SC) both in the Pacific Ocean and South Atlantic Anomaly (SAA) regions were investigated using the long-term magnetic field data obtained from the Circum-pan Pacific Magnetometer Network (CPMN) and NICT Space Weather Monitoring (NSWM) magnetometer networks. The low-latitude preliminary reverse impulse (PRI) at Okinawa (OKI: dip latitude = 37.97 degrees) in the Pacific Ocean region appeared in all the magnetic local time (MLT) sectors with the peak occurrence rate of 40% around noon. On the other hand, the PRI occurrence rate at Santa Maria (SMA: dip latitude = -34.35 degrees) near the center of the SAA region showed a significant enhancement in the daytime sector (0800-1600 h, MLT) with the peak value of 80%, which resembles the occurrence feature of the equatorial PRI. Moreover, the PRI amplitude around noon at SMA was about 3.0 times larger than that at OKI. From the calculation of the ionospheric conductivity derived from the IRI-2007 and NRLMSISE-00 models, it is shown that the height-integrated conductivity was more enhanced in the SAA region (SMA), where the ambient magnetic field intensity is weak, compared with that in the Pacific Ocean region (OKI). Therefore, the anomalous increase of the PRI occurrence and amplitude is caused by the significant enhancement of the ionospheric conductivity due to the weakness of the ambient magnetic field intensity in the SAA region.

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  109. Anomalous Enhancement of Occurrence of the Preliminary Impulse of Geomagnetic Sudden Commencement (SC) at Low Latitude in the South Atlantic Anomaly (SAA) region Reviewed

    Shinbori A, Y. Nishimura, Y. Tsuji, T. Kikuchi, T. Araki, A. Ikeda, T. Uozumi, R. Otadoy, H. Utada, J. Ishitsuka, N. Trivedi, S. Dutra, N. Schuch, S. Watari, T. Nagatsuma, K. Yumoto

    Journal of Geophysical Research: Space Physics, Volume 115, Issue A8, CiteID: A08309, doi: 10.1029/2009JA015035   Vol. 115 ( A8 )   2010.8

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  110. Temporal variations and spatial extent of the electron density enhancements in the polar magnetosphere during geomagnetic storms Reviewed

    Kitamura, N, Y. Nishimura, T. Ono, A. Kumamoto, A. Shinbori, M. Iizima, A. Matsuoka, M. R. Hairston

    J. Geophys. Res.   Vol. 115 ( A7 )   2010.7

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    DOI: 10.1029/2009JA014499

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  111. Penetration of magnetospheric electric fields to the equator and their effects on the low-latitude ionosphere during intense geomagnetic storms Reviewed

    B. Veenadhari, S. Alex, T. Kikuchi, A. Shinbori, Rajesh Singh, E. Chandrasekhar

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 115 ( A3 )   2010.3

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    The penetration of magnetospheric electric fields to the magnetic equator has been investigated for two intense magnetic storms that occurred on 31 March 2001 and 6 November 2001. The digital ground magnetic data from equatorial station Tirunelveli (TIR, 0.17 degrees S geomagnetic latitude (GML)) and low-latitude station Alibag (ABG, 10.17 degrees N GML) have been used to identify the storm time electrojet index, EEJ(Dis), which is the difference of the magnetic field variations between TIR and ABG after removing the quiet day variations. The appearance of enhanced DP 2 currents and counterelectrojets (CEJ) during the main and recovery phases of the magnetic storms is possibly due to prompt penetration of electric fields from the high latitudes. These signatures can be interpreted as a clear indicator of the eastward and westward electric fields at the equator. The observed results suggest that the magnitude of the equatorial ionospheric currents driven by the penetrating electric fields is very sensitive to ionospheric conductivity (which depends on local time). Moreover, the intensity of the DP 2 currents started decreasing during the end of the main phase of the storm despite the large negative southward IMF Bz, indicating the dominance of a well-developed shielding electric field for 1 h. As an effect of penetrating electric fields at the equator, the equatorial ionization anomaly is enhanced during the main phase (because of strong eastward electric field) and is inhibited or reduced due to the strong CEJ (because of westward electric field) during the recovery phase.

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  112. Development metadata database for upper atmosphere

    Koyama, Y, Y.-M. Tanaka, T. Kouno, H. Hayashi, T. Hori, M. Kagitani, D. Yoshida, S. UeNo, S. Abe, A. Shinbori, N. Kaneda

    Proceedings of CAWSES-II Kickoff Symposium in Japan     page: 135-136   2010

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  113. Scientific perspectives powered by IUGONET metadata database and integrated analysis tool

    Hori, T, Y. Koyama, Y.-M. Tanaka, M. Kagitani, H. Hayashi, A. Shinbori, S. UeNo, D. Yoshida, S. Abe, T. Kouno, N. Kaneda, H. Tadokoro, IUGONET project members

    Proceedings of CAWSES-II Kickoff Symposium in Japan     page: 71-74   2010

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  114. Response of convection electric fields in the magnetosphere to IMF orientation change Reviewed

    Y. Nishimura, T. Kikuchi, J. Wygant, A. Shinbori, T. Ono, A. Matsuoka, T. Nagatsuma, D. Brautigam

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 114 ( 9 )   2009.9

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    The transient response of convection electric fields in the inner magnetosphere to southward turning of the interplanetary magnetic field (IMF) is investigated using in-situ electric field observations by the CRRES and Akebono spacecraft. Electric fields earthward of the inner edge of the electron plasma sheet show quick responses simultaneously with change in ionospheric electric fields, which indicates the arrival of the first signal related to southward turning. A coordinated observation of the electric field by the CRRES and Akebono spacecraft separated by 5 RE reveals a simultaneous increase in the dawn-dusk electric field in a wide region of the inner magnetosphere. A quick response associated with the southward turning of the IMF is also identified in in-situ magnetic fields. It indicates that the southward turning of the IMF initiates simultaneous (less than 1 min) enhancements of ionospheric electric fields, convection electric fields in the inner magnetosphere, and the ring or tail current and region 2 FACs. In contrast, a quick response of convection electric fields is not identified in the electron plasma sheet. A statistical study using 161 events of IMF orientation change in 1991 confirms a prompt response within 5 min for 80% of events earthward of the electron plasma sheet, while a large time lag of more than 30 min is identified in electric fields in the electron plasma sheet. The remarkable difference in the response of electric fields indicates that electric fields in the electron plasma sheet are weakened by high conductance in the magnetically conjugated auroral ionosphere.

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  115. Magnetic latitude and local time dependence of the amplitude of geomagnetic sudden commencements Reviewed

    Shinbori Atsuki, Tsuji Yuji, Kikuchi Takashi, Araki Tohru, Watari Shinichi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 114   2009.4

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    DOI: 10.1029/2008JA013871

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  116. Magnetic latitude and local time dependence of the amplitude of geomagnetic sudden commencements Reviewed

    Shinbori A., Tsuji Y., Kikuchi T., Araki T., Watari S.

    Journal of Geophysical Research: Space Physics   Vol. 114 ( 4 )   2009.4

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    Statistical analysis of the main impulse (MI) amplitude of geomagnetic sudden commencements (SCs) in a region from the middle latitudes to equator has been made using the long-term geomagnetic field data obtained from the Yap (geomagnetic latitude, θ = 0.38°), Guam (θ = 5.22°), Okinawa (θ = 16.54°), Kakioka (θ = 27.18°), Memanbetsu (θ = 35.16°), and St. Paratunka (θ = 45.58°) stations. The magnetic local time (MLT) dependence of SC amplitude in the middle latitudes showed magnetic field variations produced by two-cell ionospheric currents (DP 2-type currents) which are driven by the dawn-to-dusk electric field accompanying a pair of field-aligned currents (FACs). The effect of the DP 2-type currents at least expands to the low latitude (θ = 16.54°). In this region, the DL part of SC produced by the enhanced Chapman-Ferraro currents can be dominant, but the DP part of SC contaminated 7% of the DL one. On the other hand, at the daytime equator between 8:00 and 16:00 (MLT), the SC amplitude is considerably enhanced with its peak amplitude of 3.24 (normalized SYM-H value) around 11:00 (MLT) due to the Cowling effect. Another interesting point is that the SC amplitude in the nighttime sector was enhanced at all the stations again, and its peak value increases with increasing magnetic latitude. This result suggests that the effect of the FACs associated with the MI phase of SC expands to the equator. Copyright 2009 by the American Geophysical Union.

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  117. Seasonal variations of the electron density distribution in the polar region during geomagnetically quiet periods near solar maximum Reviewed

    N. Kitamura, A. Shinbori, Y. Nishimura, T. Ono, M. Iizima, A. Kumamoto

    Journal of Geophysical Research: Space Physics   Vol. 114 ( A1 ) page: n/a - n/a   2009.1

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    Meridional electron density distributions above 45 degrees invariant latitude (ILAT) during geomagnetically quiet periods are statistically studied. Electron density data were obtained from plasma waves observed by the Akebono satellite from March 1989 to February 1991 (near solar maximum) in an altitude range of 274-10,500 km. Field-aligned electron density profiles were fitted by the sum of exponential and power law functions. The transition height, where the power law term equals the exponential term, is highest in the summer (at low solar zenith angle (SZA)) at similar to 4000 km and lowest in the winter (at high SZA) at similar to 1800 km in a region of ILAT &gt;= 70 degrees; this is caused by the larger scale height in the summer (similar to 550 km) than that in the winter (similar to 250 km). The largest seasonal variation and SZA dependence of the electron density are found at an altitude of similar to 2000 km with a factor of similar to 50 (similar to 10(4) /cc in the summer, similar to 10(3) /cc in the winter) in the trough, auroral, and polar cap regions. The seasonal variation and SZA dependence are smaller, about a factor of 5-10, above similar to 5000 km. Day-night asymmetries in each season (within a factor of 5) are smaller than the seasonal variation. The scale height is larger in the dayside than in the nightside in each season. These results indicate that photoionization processes in the ionosphere strongly control electron density distributions up to at least similar to 5000 km in the trough, auroral, and polar cap regions.

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  118. Magnetic latitude and local time dependence of the amplitude of geomagnetic sudden commencements Reviewed

    A. Shinbori, Y. Tsuji, T. Kikuchi, T. Araki, S. Watari

    Journal of Geophysical Research A: Space Physics   Vol. 114 ( 4 )   2009

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  119. SC-associated Ionospheric Electric Fields at Low Latitude : FM-CW Radar Observation

    Ikeda Akihiro, Yumoto Kiyofumi, Shinohara Manabu, Nozaki Kenro, Yoshikawa Akimasa, Shinbori Atsuki

    Memoirs of the Faculty of Science, Kyushu University. Series D, Earth and planetary sciences   Vol. 32 ( 1 ) page: 1 - 6   2008.2

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    We present the low-latitude ionospheric electric field during the main impulse (MI) phase of two geomagnetic sudden commencements (SCs), observed for the first time by an FM-CW radar. From our observation, the direction of the ionospheric electric field is eastward in the daytime and westward in the nighttime sectors. This difference indicates the penetration of the dawn-to-dusk polar electric field associated with the SCs into the low-latitude ionosphere.

    DOI: 10.5109/11811

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  120. SC-associated ionospheric electric fields at low latitude: FM-CW radar observation Reviewed

    Ikeda, A, K. Yumoto, M. Shinohara, K. Nozaki, A. Yoshikawa, A. Shinbori

    Mem. Fac. Sci., Kyushu Univ., Ser. D, Earth and Planet. Sci.,XXXII, 1-6   Vol. 32 ( 1 ) page: 1 - 6   2008.2

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  121. Generation mechanism of Z-mode waves in the equatorial plasmasphere Reviewed

    Nishimura Y., Ono T., Iizima M., SHINBORI A., KUMAMOTO A.

    Earth, planets and space   Vol. 59 ( 9 ) page: 1027 - 1034   2007.9

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  122. Evolution of ring current and radiation belt particles under the influence of storm-time electric fields Reviewed

    Y. Nishimura, A. Shinbori, T. Ono, M. Iizima, A. Kumamoto

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 112 ( A6 )   2007.6

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    Electric field and potential distributions in the inner magnetosphere during geomagnetic storms have been investigated using the Akebono/EFD data. Using this electric field, we study injection of ring current particles and acceleration of radiation belt electrons by single-particle calculations. During the main phase, the dawn-dusk electric field is intensified especially in a range of 2 &lt; L &lt; 5 with a maximum amplitude of 6 mV/m on the duskside, and a two-cell convection pattern with a potential difference of 180 kV is identified. The convection pattern on the equatorial plane is significantly distorted with a large potential drop of 70 kV on the dawn and dusk sectors, indicating an intrinsic source of large-scale electric field in the inner magnetosphere. The plasma sheet ions are gathered into the dusk to premidnight sector in the inner magnetosphere in the region of enhanced electric field due to the strong E x B drift. The ions are transported into around 4 R-E with an acceleration of more than 1 order of magnitude within 40 min, conserving the first adiabatic invariants. Relativistic electrons with initial energy of some hundreds of kiloelectron volts at 5 R-E are energized to more than 100 keV for 3 hours. The energy spectrum during the recovery phase of 9 October 1990 geomagnetic storm observed by the CRRES satellite is reproduced without the radial diffusion or nonadiabatic acceleration by plasma waves. It is possible that this acceleration process is the inhomogeneity of the large-scale electric field, which corresponds to the del x E term along orbits of electrons around the Earth.

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  123. Electrostatic electron cyclotron harmonic waves observed by the Akebono satellite near the equatorial region of the plasmasphere Reviewed

    Shinbori A., Ono T., Iizima M., KUMAMOTO A., SHIRAI S., HANAOKA A., OKAMOTO K., OHASHI M., OYA H.

    Earth, planets and space   Vol. 59 ( 6 ) page: 613 - 629   2007.6

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  124. Electrostatic electron cyclotron harmonic waves observed by the Akebono satellite near the equatorial region of the plasmasphere Reviewed

    新堀 淳樹

    Earth, Planets and Space (印刷中)     2007

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  125. Electrostatic electron cyclotron harmonic waves observed by the Akebono satellite near the equatorial region of the plasmasphere Reviewed

    Shinbori A., Ono T., Iizima M., Kumarnot A., Shirai S., Hanaoka A., Okamoto K., Ohashi M., Oya H.

    EARTH PLANETS AND SPACE   Vol. 59 ( 6 ) page: 613 - 629   2007

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  126. Generation mechanism of Z-mode waves in the equatorial plasmasphere Reviewed

    Yukitoshi Nishimura, T. Ono, M. Iizima, A. Shinbori, A. Kumamoto

    Earth, Planets and Space   Vol. 59 ( 9 ) page: 1027 - 1034   2007

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    In order to clarify the generation mechanism of Z-mode waves observed in the equatorial plasmasphere, the growth rate of Z-mode electromagnetic waves has been calculated under the higher-order cyclotron interaction process. Z-mode waves can interact with some tens of keV electrons with large pitch angles even in the dense cold background, and the amplitude is consistent with the Akebono plasma wave measurements. UHR and whistler mode waves are also excited by the same electron distribution, and this is also consistent with observations. The origin of these energetic electrons are identified as the ring current electrons injected into the plasmasphere by the intense large-scale electric field during geomagnetic storms, accelerated perpendicular to the ambient magnetic field and confined around the geomagnetic equator conserving the first and second adiabatic invariants. Since the intensity of Z-mode and UHR waves is associated with the development and decay of the ring current, ring current particles are most possible candidate for the free energy source of these waves. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS)
    The Seismological Society of Japan
    The Volcanological Society of Japan
    The Geodetic Society of Japan
    The Japanese Society for Planetary Sciences
    TERRAPUB.

    DOI: 10.1186/BF03352043

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  127. Generation mechanism of Z-mode waves in the equatorial plasmasphere Reviewed

    Nishimura Y., Ono T., Iizima M., Shinbori A., Kumamoto A.

    EARTH PLANETS AND SPACE   Vol. 59 ( 9 ) page: 1027 - 1034   2007

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  128. Electrostatic electron cyclotron harmonic waves observed by the Akebono satellite near the equatorial region of the plasmasphere Reviewed

    A. Shinbori, T. Ono, M. Iizima, A. Kumarnot, S. Shirai, A. Hanaoka, K. Okamoto, M. Ohashi, H. Oya

    EARTH PLANETS AND SPACE   Vol. 59 ( 6 ) page: 613 - 629   2007

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    Analysis of the plasma wave observation data provided by the plasma waves and sounder experiment (PWS) on board the Akebono satellite frequently reveals the presence of electrostatic electron cyclotron harmonic (ESCH) waves in the low-latitude region (MLAT &lt; 45 degrees) of the plasmasphere within an altitude range from about 3000 km to the apogee of the satellite (initial apogee was 10,500 km). Even at moderate or low geomagnetic activity, intense ESCH waves often appear near the equatorial region of the plasmasphere above the upper hybrid resonance (UHR) frequency at the lowest harmonic number branch of the f(Qn) ESCH waves. We identified these plasma waves as the equatorial plasmasphere f(Qn) waves (EP-f(Qn)). The spectra of the EP-f(Qn) waves are characterized by a narrow band structure and by a strong nature, with a wave intensity that ranges from 3.46 x 10(-8) to 3.31 X 10(-4) V/m. The maximum intensity is nearly coincident with the upper limit of the PWS receiver in the low-gain mode. Statistical analysis results reveal that the EP-f(Qn) waves are observable in all the local time sectors; however, the occurrence probability shows a clear enhancement in the early morning sector of 01-03 MLT in the plasmasphere. The EP-f(Qn) wave activities are suppressed within a period of strong magnetic disturbances as well as solar minimum phase. The linear dispersion relation analysis using a two-component plasma model reveals that supra-thermal plasma with the energy of about 750 eV and with a large temperature anisotropy (A = T-perp/T-parallel - 1 &gt; 40) must be present in order to realize an appearance of a positive growth rate at the observed frequency and propagation angle of the ESCH waves. Since the hot plasma with such a high anisotropy has not been detected, the validity of the present two-component plasma model remains an open question. The occurrence feature of the ESCH waves showed that there is a constant activation or a constant flow-in of free energy to generate the strong plasma instability of ESCH waves near the post-midnight sector of the plasmasphere. The existence of ESCH waves revealed that the nature of the plasmaspheric plasma is more turbulent and active than has been believed.

    DOI: 10.1186/BF03352723

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  129. Storm-time electric field distribution in the inner magnetosphere Reviewed

    Y. Nishimura, A. Shinbori, T. Ono, M. Iizima, A. Kumamoto

    GEOPHYSICAL RESEARCH LETTERS   Vol. 33 ( 22 )   2006.11

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    The distribution of the storm-time electric field in the inner magnetosphere has been investigated by using the Akebono/EFD data within a period from 1989 to 1995. During the main phase of geomagnetic storms, the strong electric field appears between L = 2 and L = 6 in both dawn and dusk sectors with the magnitude from 2 to 4 mV/m, and the maximum value appears at L = 3 in the dusk sector. During the recovery and weakly disturbed period, the region with intense electric field moves outward with decreasing the amplitude. This structure of the localized electric field is quite different from the Volland-Stern electric field model, suggesting the existence of another electric field source other than the large-scale convection electric field. During quiet periods, although the electric field fairly follows the corotation electric field, the distribution at L = 3.5 indicates a small deviation from pure corotation.

    DOI: 10.1029/2006GL027510

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  130. Enhancements of magnetospheric convection electric field in the inner magnetosphere associated with sudden commencements Reviewed

    Shinbori, A, T. Ono, M. Iizima, A. Kumamoto

    Advances in Space Research, Volume 38, Issue 8, 1595-1607, doi: 10.1016/j.asr.2005.05.082     2006.1

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    DOI: 10.1016/j.asr.2005.05.082

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  131. Enhancements of magnetospheric convection electric field associated with sudden commencements in the inner magnetosphere and plasmasphere regions Reviewed

    新堀 淳樹

    Advances in space Research 38     page: 1595 - 1607   2006

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  132. Enhancements of magnetospheric convection electric field associated with sudden commencements in the inner magnetosphere and plasmasphere regions Reviewed

    A. Shinbori, T. Ono, M. Iizima, A. Kumamoto, Y. Nishimura

    ADVANCES IN SPACE RESEARCH   Vol. 38 ( 8 ) page: 1595 - 1607   2006

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    Electric field variations in the inner magnetosphere and plasmasphere regions associated with sudden commencements (SCs) are investigated by using the observation data of the Akebono satellite which has been carried out more than 15 years since 1989. 117 of 153 SC events in the low-latitude (MLAT &lt; 45 degrees) region, which occurred within a period from March 1989 to January 1996, showed a shift of the magnetospheric convection electric field with the magnitude of 0.1-3.2 mV/m about 1 min after the electric field signature with a bi-polar waveform due to the passage of fast-mode hydromagnetic (HM) waves. The increase of the convection electric field takes place in the entire magnetic local time sector in the inner magnetosphere. The amplitude does not depend on L-value and magnetic local time but is proportional to the SC amplitude measured at Kakioka. The majority of the electric field enhancements persist for about 4-14 min. The origin of the convection electric field in the inner magnetosphere is a plasma motion caused by the compression of the magnetosphere due to the solar wind shock and discontinuity. (C) 2005 COSPAR. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.asr.2005.05.082

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  133. Statistical studies of fast and slow Z-mode plasma waves in and beyond the equatorial plasmasphere based on long-term Akebono observations Reviewed

    Yukitoshi Nishimura, T. Ono, M. Iizima, A. Shinbori, A. Kumamoto, H. Oya

    Earth, Planets and Space   Vol. 58 ( 3 ) page: 343 - 346   2006

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    In order to investigate spatial and temporal variations of fast and slow Z-mode waves frequently observed in the equatorial plasmasphere, statistical studies have been performed by using plasma wave observation data obtained by the Akebono satellite within a period from 1989 to 1995. It has been clarified that fast and slow Z-mode waves are intensified within ±5° of geomagnetic latitudes in an altitude range from 6000 km to the apogee (10500 km) of the satellite without obvious local time dependence. Long-term averaged intensity of fast Z-mode waves has almost the same orders of magnitude as that of slow Z-mode waves. These results indicate that significant part of fast Z-mode waves are not produced by the linear mode conversion process from slow Z-mode waves, but excited by more direct process. Furthermore, the region of intensified fast and slow Z-mode waves has been spread in a wider geomagnetic latitude range of ±10° during geomagnetic storms. These evidences suggest that one of the possible free energy sources is ring current particles injected into the equatorial region of the plasmasphere during geomagnetic storms. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS)
    The Seismological Society of Japan
    The Volcanological Society of Japan
    The Geodetic Society of Japan
    The Japanese Society for Planetary Sciences
    TERRAPUB.

    DOI: 10.1186/BF03351930

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  134. Electrodynamics in the duskside inner magnetosphere and plasmasphere during a super magnetic storm on March 13-15, 1989 Reviewed

    A Shinbori, Y Nishimura, T Ono, M Iizima, A Kumamoto, H Oya

    EARTH PLANETS AND SPACE   Vol. 57 ( 7 ) page: 643 - 659   2005

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    Variations of cold plasma density distribution and large-scale electric field in the inner magnetosphere and plasmasphere during a geomagnetic storm were investigated by using the observation data of the Akebono satellite which has been carried out for more than 15 yeas since March, 1989. We focus on the super geomagnetic storm on March 13-15, 1989, for which the maximum negative excursion of the Dst index was -589 nT. During the main phase of the magnetic storm, the strong convection electric field with a spatially inhomogeneous structure appears in the inner magnetosphere between L = 2.0 and 7.0. The averaged intensity of the electric field was in a range of about 2.5-9.2 mV/m. The spatial distribution in the magnetic equatorial region indicates that the magnitude within an L-value range of 2.2-7.0 is much larger than that observed at L = 7.0-10.0. Associated with the appearance of the strong convection electric field, the cold plasma density near the trough region around L = 3.0-6.0 was enhanced with one or two order magnitude, compared with that in the magnetically quiet condition. This implies that a mount of the ionospheric plasma may be supplied from the topside ionosphere into the trough and plasmasphere regions by the frictional heating due to the fast plasma convection in the ionosphere as pointed out by previous studies on the enhancements of plasma density in these regions, based on incoherent scatter radar and total electron content (TEC) observations (e.g., Yeh and Foster, 1990; Foster et al., 2004). During the recovery phase of the magnetic storm, the convection electric field observed in the inner magnetosphere and plasmasphere regions recovers within 3-4 days almost up to the level of the magnetically quiet condition.

    DOI: 10.1186/BF03351843

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  135. SC related electric and magnetic field phenomena observed by the Akebono satellite inside the plasmasphere Reviewed

    A Shinbori, T Ono, M Iizima, A Kumamoto

    EARTH PLANETS AND SPACE   Vol. 56 ( 2 ) page: 269 - 282   2004

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    Electric and magnetic field variations inside the plasmasphere associated with SCs identified on the ground are analyzed based on the Akebono satellite observations which have been carried out more than 13 years since March 1989. 126 electric field observation data corresponding to SCs show abrupt change of intensity as well as direction within a few minutes inside the plasmasphere. Temporal variations of the electric field showed a bipolar waveform with the amplitude range of 0.2-38 mV/m. The electric field signature is followed by a dumping oscillation with the period of Pc3-4 ranges. The magnetic field variations of 33 SCs also show an abrupt increase of 0.2-65 nT within a few minutes, which indicate the compression of the magnetosphere due to the discontinuity of solar wind. The initial excursion of the electric field during SCs tends to be directed westward. The amplitude does not show a dependence on magnetic local time that has been observed outside the plasmasphere. The magnitude of the electric field variations tends to be proportional with the power of 0.6 to the magnetic field variation in the plasmasphere. The Poynting vector of the initial SC impulse is directed toward the earth, which suggests that energy of magnetic disturbances associated with SCs propagates toward the earth inside the plasmasphere with the refraction due to the plasma density gradient. One of the most interesting results from the present study is that a DC offset of the Ey component of the electric field appears after the initial electric field impulse associated with SCs. This signature is interpreted to be a magnetospheric convection electric field penetration into the inner plasmasphere (L=2.5). The intensity of the offset of the Ey field gradually increases by 0.5-2.0 mV/m about 1-2 minutes after the onset of the initial electric field impulse and persists about 10-30 minutes.

    DOI: 10.1186/BF03353409

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  136. Sudden commencements related plasma waves observed by the Akebono satellite in the polar region and inside the plasmasphere region Reviewed

    A Shinbori, T Ono, M Iizima, A Kumamoto, H Oya

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 108 ( A12 )   2003.12

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    Plasma wave phenomena associated with sudden commencements (SC) are analyzed using the database of the Akebono satellite observations that have been carried out for more than 13 years since March 1989. All the 719 data sets simultaneously observed in the periods of SC events show that plasma waves are enhanced with one-to-one correspondence to SCs in entire regions of the polar cap, auroral zone, and plasmasphere within a response time of +/-90 s. In the middle latitude and equatorial regions of the plasmasphere, intensification and frequency shift of electromagnetic whistler mode, LHR waves, and ion cyclotron harmonic waves are found. The electric field variations in this region also show clear response to the onset of SCs with the amplitude of 0.2-30 mV/m. The variations are observed in the nightside as well as dayside sectors, and no clear dependence of magnetic latitude, local time, and L shell is found. On the other hand, electrostatic whistler mode waves and electromagnetic ion cyclotron waves which show broadband spectra are generated in the high-latitude region. Spectra of low-energy particles observed simultaneously with the enhancement of these plasma waves show that electron fluxes are enhanced in all of pitch angle bins of the low-energy particle detector onboard the Akebono satellite. Near the cusp region, the ion fluxes are more enhanced in the upward direction than in the downward direction along the magnetic field lines. In about half of the cases of the high-latitude events, sudden appearance and intensification of AKR are also found after the onsets of SC. The delay time between the onsets of SC and AKR enhancement shows several minutes with the average time of 5.7 min. Time differences between the onsets of SC measured at Kakioka Magnetic Observatory and plasma wave enhancements observed by the Akebono satellite show positive correlation with possible delay time according to the propagation route of SC disturbances. Propagation character of SC disturbances shows two group signatures: one group takes a route which crosses the geomagnetic equator region with an average speed of 389.5 km/s. The speed is almost consistent with plasmaspheric fast-mode MHD wave velocity. The other group takes a route which starts from the dayside cusp region. In the second case, the SC disturbances propagate through the polar ionosphere region from the dayside to the nightside sectors with an average speed of 47 km/ s in the X-GSM coordinate corresponding to the ionospheric fast-mode MHD wave velocity.

    DOI: 10.1029/2003JA009964

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  137. SC-related kilometric and hectometric radiations observed by the Akebono satellite in the polar regions Reviewed

    Shinbori, A, T. Ono, M. Izima, K. Kumamoto, H. Oya

    Advances in polar upper atmosphere research   Vol. 17   page: 60 - 76   2003.9

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  138. SC-triggered plasma waves observed by the Akebono satellite in the polar regions and the plasmasphere Reviewed

    Shinbori, A, T. Ono, H. Oya

    Advances in polar upper atmosphere research   Vol. 16   page: 126 - 135   2002.9

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    Plasma wave phenomena associated with sudden commencements (SCs) were analyzed based on observations conducted with the Akebono satellite, which has been collecting data for more than 13 years (since March 1989). Simultaneous plasma wave observation data for 257 SCs reveal that enhanced plasma waves are observed with an exact one-to-one correspondence with the SCs throughout the entire observation region, including the polar and plasmasphere regions. Electromagnetic whistler mode and ion cyclotron waves are enhanced in the low latitude plasmasphere, while electrostatic whistler mode and electromagnetic ion cyclotron waves are generated in the polar region. The onset times of the SC-triggered plasma waves exhibit a delay or lead time characteristic, compared with the onset times of SCs identified by the Kakioka Magnetic Observatory, with a time resolution of 1 s. By comparing the difference in SCs and enhanced electron plasma waves onset times, the propagation route of the SC disturbances can be identified in the plasmasphere.

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Books 2

  1. 解説:地磁気急始変化 (Geomagnetic Sudden Commencement)

    荒木徹、菊池崇、佐納康治、新堀淳樹、永野宏、藤田茂( Role: Joint author ,  第3章 磁気圏におけるSCとその関連現象)

    名古屋大学  2023.9 

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    Total pages:373   Responsible for pages:156-260   Language:Japanese Book type:Textbook, survey, introduction

    DOI: https://doi.org/10.18999/2007346

  2. 磁気圏-電離圏結合過程の基本原理とその未解明問題 Reviewed

    新堀淳樹( Role: Sole author)

    極地研電子ライブラリー  2023 

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    Language:Japanese Book type:Textbook, survey, introduction

    DOI: http://doi.org/10.15094/00017226

MISC 225

  1. An extreme erosion of the plasmasphere during the 7-10 September 2017 storm

    OBANA Yuki, MARUYAMA Naomi, MARUYAMA Naomi, SHINBORI Atsuki, HASHIMOTO Kumiko K., FEDRIZZI Mariangel, FEDRIZZI Mariangel, NOSE Masahito, OTSUKA Yuichi, NISHITANI Nozomu, HORI Tomoaki, KUMAMOTO Atsushi, TSUCHIYA Fuminori, MATSUDA Shoya, MATSUOKA Ayako, KASAHARA Yoshiya, YOSHIKAWA Akimasa, MIYOSHI Yoshizumi, SHINOHARA Iku

    日本地球惑星科学連合大会予稿集(Web)   Vol. 2019   2019

  2. Dynamics of the Ionosphere/Plasmasphere System: Comparisons Between Arase/PWE Observations and the IPE Model Simulations

    OBANA Yuki, MARUYAMA Naomi, SHINBORI Atsuki, HASHIMOTO Kumiko, FEDRIZZI Mariangel, NOSE Masahito, OTSUKA Yuichi, NISHITANI Nozomu, HORI Tomoaki, KUMAMOTO Atsushi, TSUCHIYA Fuminori, MATSUDA Shoya, MATSUOKA Ayako, KASAHARA Yoshiya, YOSHIKAWA Akimasa, MIYOSHI Yoshizumi, SHINOHARA Iku

    地球電磁気・地球惑星圏学会総会及び講演会(Web)   Vol. 146th   2019

  3. あらせ(ERG)で観測されたヘクトメータ線スペクトルの励起源と波動特性

    橋本弘藏, 熊本篤志, 土屋史紀, 笠原禎也, 三好由純, 大塚雄一, 新堀淳樹, 横山竜宏, 長野勇, 松岡彩子

    地球電磁気・地球惑星圏学会総会及び講演会(Web)   Vol. 146th   2019

  4. レベルセット法を用いた陽子オーロラの空間特徴の検出

    井上智寛, 尾崎光紀, 八木谷聡, 塩川和夫, 三好由純, 新堀淳樹, 大塚雄一, 片岡龍峰, 海老原祐輔, 津川卓也, 西岡未知

    電気関係学会北陸支部連合大会講演論文集(CD-ROM)   Vol. 2018   page: ROMBUNNO.F2‐37   2018.9

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  5. Wire Probe Antenna and Electric Field Detector of Plasma Wave Experiment aboard ARASE: Evaluation results-II

    KASABA Yasumasa, ISHISAKA Keigo, KASAHARA Yoshiya, IMACHI Tomohiko, YAGITANI Satoshi, KOJIMA Hirotsugu, MATSUDA Shoya, SHOJI Masafumi, KURITA Satoshi, HORI Tomoaki, SHINBORI Atsuki, TERAMOTO Mariko, MIYOSHI Yoshizumi, NAKAGAWA Tomoko, TAKAHASHI Naoko, NISHIMURA Yukitoshi, MATSUOKA Ayako, KUMAMOTO Atsushi, TSUCHIYA Fuminori, NOMURA Reiko

    地球電磁気・地球惑星圏学会総会及び講演会(Web)   Vol. 144th   2018

  6. Wire Probe Antenna and Electric Field Detector of Plasma Wave Experiment aboard ARASE: Specifications and Evaluation results

    KASABA Yasumasa, ISHISAKA Keigo, KASAHARA Yoshiya, IMACHI Tomohiko, YAGITANI Satoshi, KOJIMA Hirotsugu, MATSUDA Shoya, SHOJI Masafumi, KURITA Satoshi, HORI Tomoaki, SHINBORI Atsuki, TERAMOTO Mariko, MIYOSHI Yoshizumi, NAKAGAWA Tomoko, TAKAHASHI Naoko, NISHIMURA Yukitoshi, MATSUOKA Ayako, KUMAMOTO Atsushi, TSUCHIYA Fuminori, NOMURA Reiko

    地球電磁気・地球惑星圏学会総会及び講演会(Web)   Vol. 142nd   2017

  7. Local time and seasonal variations of the amplitude of the main impulse (MI) of geomagnetic sudden commencements in the low-latitude and equatorial regions

    SHINBORI Atsuki, KIKUCHI Takashi, ARAKI Tohru, IKEDA Akihiro, UOZUMI Teiji, UTADA Hisashi, HO Commodore, Romeo Isidre, NAGATSUMA Tsutomu, YOSHIKAWA Akimasa

    日本地球惑星科学連合大会予稿集(Web)   Vol. 2017   page: ROMBUNNO.PEM14‐P11 (WEB ONLY)   2017

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  8. Thermal and low-energy ion outflows in and through the polar cap: The polar wind and the low-energy component of the cleft ion fountain Reviewed

    Kitamura, N, K. Seki, Y. Nishimura, T. Abe, M. Yamada, S. Watanabe, A. Kumamoto, A. Shinbori, A. W. Yau

    AGU Geophysical Monograph     page: .   2016.10

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  9. Relationship between solar wind dynamic pressure and amplitude of geomagnetic sudden commencement (SC) Reviewed

    Araki Tohru, Shinbori Atsuki

    EARTH PLANETS AND SPACE   Vol. 68   2016.5

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  10. Measurement of momentum flux using two meteor radars in Indonesia Reviewed

    Matsumoto Naoki, Shinbori Atsuki, Riggin Dennis M., Tsuda Toshitaka

    ANNALES GEOPHYSICAE   Vol. 34 ( 3 ) page: 369-377   2016.5

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  11. Simultaneous ground- and satellite-based observation of MF/HF auroral radio emissions Reviewed

    Sato Yuka, Kumamoto Atsushi, Katoh Yuto, Shinbori Atsuki, Kadokura Akira, Ogawa Yasunobu

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 121 ( 5 ) page: 4530-4541   2016.5

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    DOI: 10.1002/2015JA022101

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  12. 超稠密GNSS受信ネットワークによる電離層TECの微細変動の特性

    Takeda,Y, N.Ito, T.Tsuda, A. Shinbori

    Japan Geoscience Union Meeting 2016     2016.5

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  13. Prototype Development of the JavaFX-based iUgonet Data Analysis Software (JudasFX) Reviewed

    Yukinobu KOYAMA, Yuka SATO, Shinya NAKANO, Manabu YAGI, Yoshimasa TANAKA, Shuji ABE, Masahito NOSE, Kei KURAKAWA, Daisuke IKEDA, Norio UMEMURA, Atsuki SHINBORI, Satoru UeNo

    Journal of Space Science Informatics Japan   ( 第5号 ) page: .   2016.3

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  14. Long-term variation of ionospheric electric field estimated from the amplitude of geomagnetic solar quiet daily variation

    Shinbori, A, Y. Koyama, M. Nose, T. Hori, Y. Otsuka

    2015 ISEE workshop: International GEMSIS and ASINACTR-G2602 Workshop: Future Perspectives of Researches in Space Physics     2016.3

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  15. 地磁気日変化振幅から推定される電離圏電場の長期変動について

    新堀淳樹, 小山幸伸, 能勢正仁, 堀 智昭, 大塚雄一

        2016.3

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  16. 多様な観測データベースを用いた地球大気環境の長期変動に関する研究

    新堀 淳樹

    第307回生存圏シンポジウム「生存圏ミッションシンポジウム」     2016.3

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  17. Evaluation of momentum flux with radar Reviewed

    Riggin Dennis M., Tsuda Toshitaka, Shinbori Atsuki

    JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS   Vol. 142   page: 98-107   2016.2

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  18. Response of the incompressible ionosphere to the compression of the magnetosphere during the geomagnetic sudden commencements Reviewed

    T. Kikuchi, K. K. Hashimoto, I. Tomizawa, Y. Ebihara, Y. Nishimura, T. Araki, A. Shinbori, B. Veenadhari, T. Tanaka, T. Nagatsuma

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 121 ( 2 ) page: 1536-1556   2016.2

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    The ionospheric plasma in midlatitude moves upward/downward during the geomagnetic sudden commencement causing the HF Doppler frequency changes; SCF (+-) and (-+) on the dayside and nightside, respectively, except for the SCF (+-) in the evening as found by Kikuchi et al. (1985). Although the preliminary and main frequency deviations (PFD, MFD) of the SCF have been attributed to the dusk-to-dawn and dawn-to-dusk potential electric fields, there still remain questions if the positive PFD can be caused by the compressional magnetohydrodynamic (MHD) wave and what causes the evening anomaly of the SCF. With the HF Doppler sounder, we show that the dayside ionosphere moves upward toward the Sun during the main impulse (MI) of the SC, when the compressional wave is supposed to push the ionosphere downward. The motion of the ionosphere is shown to be correlated with the equatorial electrojet, matching the potential electric field transmitted with the ionospheric currents from the polar ionosphere. We confirmed that the electric field of the compressional wave is severely suppressed by the conducting ionosphere and reproduced the SC electric fields using the global MHD simulation in which the potential solver is employed. The model calculations well reproduced the preliminary impulse and MI electric fields and their evening anomaly. It is suggested that the electric potential is transmitted from the polar ionosphere to the equator by the zeroth-order transverse magnetic (TM0) mode waves in the Earth-ionosphere waveguide. The near-instantaneous transmission of the electric potential leads to instantaneous global response of the incompressible ionosphere.

    DOI: 10.1002/2015JA022166

    Web of Science

  19. IUGONETプロジェクトの活動報告

    新堀淳樹, 八木学, 田中良昌, 梅村宣生, 上野悟, 能勢正仁, 小山幸伸, 阿部修司, IUGONET, プロジェクトチーム

    太陽研連シンポジウム「ひので10年目の成果とSolar-Cを柱とする太陽研究の新展開」     2016.2

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  20. Seasonal variation of the amplitude of the main impulse (MI) of sudden commencements in the low-latitude and equatorial regions

    SHINBORI Atsuki, KIKUCHI Takashi, ARAKI Tohru, IKEDA Akihiro, UOZUMI Teiji, UTADA Hisashi, NAGATSUMA Tsutomu, YOSHIKAWA Akimasa

    地球電磁気・地球惑星圏学会総会及び講演会(Web)   Vol. 140th   page: ROMBUNNO.R010‐08 (WEB ONLY)   2016

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  21. A study of long-term and short-term variations in space and Earth's atmosphere environments associated with solar activity using different kinds of ground-based and satellite observation data

      ( 12 ) page: 67 - 102   2016

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  22. Long-term variation in the ionosphere and lower thermosphere as seen in the geomagnetic solar quiet daily variation Reviewed

    Atsuki Shinbori, Yukinobu Koyama, Masahito Nose, Tomoaki Hori, Tomoaki, Yuichi Otsuka

    AGU Fall Meeting 2015     2015.12

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  23. 地上‐衛星観測に基づく、磁気嵐時の電離圏・プラズマ圏電場変動について

    新堀 淳樹

    ワークショップ「プラズマ圏の観測と予測モデルの構築」     2015.12

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  24. IMF-By dependence of transient ionospheric flow perturbation associated with sudden impulses: SuperDARN observations Reviewed

    Hori Tomoaki, Shinbori Atsuki, Fujita Shigeru, Nishitani Nozomu

    EARTH PLANETS AND SPACE   Vol. 67   2015.11

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  25. 地磁気日変化に見られる電離圏、下部熱圏における長期変動特性

    新堀淳樹, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一

    第138回 SGEPSS総会および講演会     2015.11

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  26. 地磁気静穏日変化から推定される電離圏電場の長期変動

    新堀淳樹, 小山幸伸, 田中良昌, 佐藤由佳, 門倉昭

    第6回極域科学シンポジウム     2015.11

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  27. IUGONETデータ解析ソフトを利用した太陽地球系結合研究

    新堀淳樹, 八木学, 田中良昌, 梅村宣生, 上野悟, 小山幸伸, 阿部修司, IUGONET, プロジェクトチーム

    オープンサイエンスデータ推進ワークショップ     2015.9

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  28. 太陽地球結合系研究のための IUGONET データ解析システム

    新堀淳樹, 八木学, 田中良昌, 梅村宣生, 上野悟, 小山幸伸, 阿部修司, IUGONET, プロジェクトチーム

    宇宙地球惑星科学若手会「夏の学校2015」     2015.9

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  29. 京大RISHにおける大気レーダー観測データベースの公開

    橋口浩之, 津田敏隆, 塩谷雅人, 山本衛, 新堀淳樹

    オープンサイエンスデータ推進ワークショップ     2015.9

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  30. GUI-データ解析

    新堀 淳樹

    第2回「太陽地球環境データ解析に基づく超高層大気の空間・時間変動の解明」 第290回生存圏シンポジウム/平成27年度名大STE研研究集会/平成27年度極地研研究集会     2015.8

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  31. Long-Term Variation in the Upper Atmosphere as Seen in the Geomagnetic Solar Quiet Daily Variation Invited Reviewed

    Atsuki Shinbori, Yukinobu Koyama, Masahito Nose, Tomoaki Hori, Tomoaki, Yuichi Otsuka, Akiyo Yatagai

    Asia Oceania Geoscience Society 2015     2015.8

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  32. 地磁気日変動振幅から見積もられる下部熱圏における風速の長期変動について

    新堀淳樹, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一

    中間圏・熱圏・電離圏 (MTI) 研究集会     2015.8

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  33. 地磁気日変化振幅に見られる超高層大気変動について

    新堀淳樹, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一, IUGONETプロジェクトチーム

    第2回「太陽地球環境データ解析に基づく超高層大気の空間・時間変動の解明」 第290回生存圏シンポジウム/平成27年度名大STE研研究集会/平成27年度極地研研究集会     2015.8

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  34. Response of ionospheric electric fields at mid-low latitudes during sudden commencements Reviewed

    N. Takahashi, Y. Kasaba, A. Shinbori, Y. Nishimura, T. Kikuchi, Y. Ebihara, T. Nagatsuma

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 120 ( 6 ) page: 4849-4862   2015.6

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    Using in situ observations from the Republic of China Satellite-1 spacecraft, we investigated the time response and local time dependence of the ionospheric electric field at mid-low latitudes associated with geomagnetic sudden commencements (SCs) that occurred from 1999 to 2004. We found that the ionospheric electric field variation associated with SCs instantaneously responds to the preliminary impulse (PI) signature on the ground regardless of spacecraft local time. Our statistical analysis also supports the global instant transmission of electric field from the polar region. In contrast, the peak time detected in the ionospheric electric field is earlier than that of the equatorial geomagnetic field (similar to 20s before in the PI phase). Based on the ground-ionosphere waveguide model, this time lag can be attributed to the latitudinal difference of ionospheric conductivity. However, the local time distribution of the initial excursion of ionospheric electric field shows that dusk-to-dawn ionospheric electric fields develop during the PI phase. Moreover, the westward electric field in the ionosphere, which produces the preliminary reverse impulse of the geomagnetic field on the dayside feature, appears at 18-22h LT where the ionospheric conductivity beyond the duskside terminator (18h LT) is lower than on the dayside. The result of a magnetohydrodynamic simulation for an ideal SC shows that the electric potential distribution is asymmetric with respect to the noon-midnight meridian. This produces the local time distribution of ionospheric electric fields similar to the observed result, which can be explained by the divergence of the Hall current under nonuniform ionospheric conductivity.

    DOI: 10.1002/2015JA021309

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  35. Long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet daily variation Invited Reviewed

    Atsuki Shinbori, Yukinobu Koyama, Masahito Nose, Tomoaki Hori, Tomoaki, Yuichi Otsuka, Akiyo Yatagai

    26th IUGG General Assembly     2015.6

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  36. Characteristics of long-term variation of the geomagnetic solar quiet daily variation

    Atsuki Shinbori, Yukinobu Koyama, Masahito Nose, Tomoaki Hori, Tomoaki, Yuichi Otsuka, Akiyo Yatagai

    Japan Geoscience Union 2015     2015.5

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  37. Long-term variation of upper atmosphere using the IUGONET metadata database and data analysis software (UDAS)

    Atsuki Shinbori, Manabu Yagi, Yoshimasa Tanaka, Norio Umemura, Satoru Ueno, Yukinobu Koyama, Shuji Abe, Akiyo Yatagai

    Japan Geoscience Union 2015     2015.5

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  38. The capacity-building and science-enabling activities of the IUGONET to the solar-terrestrial research community Reviewed

    Yatagai, A, Y. Sato, A. Shinbori, S. Abe, S. UeNo, IUGONET Team

    Earth, Planets and Space     page: .   2015.1

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  39. P233 レーダー長期観測による赤道域の中間圏・下部熱圏における大気力学過程(ポスターセッション)

    松本 直樹, 津田 敏隆, 新堀 淳樹

    大会講演予講集   Vol. 107   page: 264 - 264   2015

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    CiNii Books

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  40. Long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet daily variation Reviewed

    Shinbori, A, Y. Koyama, M, Nose, T. Hori, Y. Otsuka, A. Yatagai

    Earth, Planets and Space   Vol. 65 ( 155 ) page: .   2014.12

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  41. Characteristics of long-term variation in the amplitude of the geomagnetic solar quiet (Sq) daily variation using the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) data analysis system Reviewed

    Shinbori, A, Y. Koyama, M. Nose, T. Hori, Y. Otsuka, A. Yatagai

    AGU Fall Meeting 2014   Vol. 12   page: WDS179-WDS184   2014.12

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    DOI: 10.2481/dsj.WDS-030

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  42. 極域-中緯度における地磁気静穏日変化の長期変動特性

    新堀淳樹, 小山幸伸, 田中良昌, 佐藤由佳, 門倉昭

    第5回極域科学シンポジウム     2014.12

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  43. An overview of the IUGONET project and meta database system

    Shinbori, A, M. Yagi, Y. Tanaka, Y. Sato, A. Yatagai, N. Umemura, T. Hori, S. UeNo, Y. Koyama, S. Abe, IUGONET project team

    A meet on ‘Inter-university Upper atmosphere Global Observation NETwork (IUGONET)’     2014.11

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  44. Long-term variation of the upper atmosphere and ionosphere as seen in the geomagnetic solar quiet (Sq) daily variation

    Shinbori, A, Y. Koyama, M. Nose, T. Hori, Y. Otsuka, A. Yatagai

    A meet on ‘Inter-university Upper atmosphere Global Observation NETwork (IUGONET)’     2014.11

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  45. Mini-training of how to use the IUGONET data analysis software (UDAS)

    Atsuki Shinbori

    A meet on ‘Inter-university Upper atmosphere Global Observation NETwork (IUGONET)’     2014.11

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  46. 地磁気静穏日変化振幅の長期変動特性

    新堀淳樹, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一, 谷田貝亜紀代, IUGONETプロジェクトチーム

    地球電磁気・地球惑星圏学会第136回総会及び講演会     2014.11

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  47. 全球地磁気データを用いた磁気嵐時のグローバルな電離圏電流分布

    新堀淳樹, 堀智昭, 田中良昌, 小山幸伸, 菊池崇, 長妻努

    地球電磁気・地球惑星圏学会第136回総会及び講演会     2014.11

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  48. Temporal and spatial variations of storm-time ionospheric currents as seen in the geomagnetic field

    Shinbori, A, T. Hori, Y. Tanaka, Y. Koyama, T. Kikuchi, T. Nagatsuma

    The 12th International Conference on Substorms (ICS-12)     2014.11

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  49. Interuniversity upper atmosphere global observation network (IUGONET) meta-database and analysis software Reviewed

    Yatagai, A, Y. Tanaka, S. Abe, A. Shinbori, M. Yagi, S. UeNo, Y. Koyama, N. Umemura, M. Nosé, T Hori, Y Sato, N. O. Hashiguchi, N Kaneda, IUGONET project team

    Data Science Journal   Vol. 13   page: PDA37-PDA43   2014.10

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    DOI: 10.2481/dsj.IFPDA-07

  50. Progress of the IUGONET system - metadata database for upper atmosphere ground-based observation data Reviewed

    Abe Shuji, Umemura Norio, Koyama Yukinobu, Tanaka Yoshimasa, Yagi Manabu, Yatagai Akiyo, Shinbori Atsuki, UeNo Satoru, Sato Yuka, Kaneda Naoki

    EARTH PLANETS AND SPACE   Vol. 66   2014.10

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    DOI: 10.1186/1880-5981-66-133

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  51. IUGONET データ解析システムを用いた地磁気静穏日変化振幅の長期変動に関する研究

    新堀淳樹, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一, 谷田貝亜紀代, IUGONETプロジェクトチーム

    平成26年度「MTI 研究集会」+「ISS-IMAP 研究集会」合同ワークショップ     2014.9

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  52. IUGONETデータ解析システムを用いた太陽地球結合系の長期変動研究

    新堀淳樹, 八木学, 田中良昌, 谷田貝亜紀代, 梅村宣生, 上野悟, 小山幸伸, 阿部修司, IUGONET, プロジェクトチーム

    第8回MUレーダー・赤道大気レーダーシンポジウム     2014.9

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  53. An Interactive Data Language software package to calculate ionospheric conductivity by using numerical models Reviewed

    Koyamaa Yukinobu, Shinbori Atsuki, Tanaka Yoshimasa, Hori Tomoaki, Nose Masahito, Oimatsu Satoshi

    COMPUTER PHYSICS COMMUNICATIONS   Vol. 185 ( 12 ) page: 3398-3405   2014.8

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  54. Global Distributions of Storm-time Ionospheric Currents and Electric Fields as Seen in Geomagnetic Field Variations Reviewed

    Shinbori, A, T. Hori, Y. Tanaka, Y. Koyama, T. Kikuchi, T. Nagatsuma

    Asia Oceania Geoscience Society 2014     2014.8

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  55. Long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet (Sq) daily variation Reviewed

    Shinbori, A, Y. Koyama, M. Nose, T. Hori, Y. Otsuka, A. Yatagai

    Asia Oceania Geoscience Society 2014     2014.8

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  56. IUGONETツールがもたらす太陽地球科学研究への貢献

    新堀淳樹, 八木学, 田中良昌, 谷田貝亜紀代, 梅村宣生, 上野悟, 小山幸伸, 阿部修司, IUGONET, プロジェクトチーム

    平成26年度IUGONET中間報告会     2014.8

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  57. TDAS/UDAS GUIによる操作2 (データ解析、軸やラベルの変更方法等)

    新堀 淳樹

    平成26年度国立極地研究所研究集会 「太陽-地球大気の地上多点観測データ総合解析ワークショップ」     2014.8

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  58. Contribution of the IUGONET data analysis system to a study on coupling processes in the solar-terrestrial system

    Atsuki SHINBORI, Manabu YAGI, Yoshimasa TANAKA, Yuka SATO, Akiyo YATAGAI, Norio UMEMURA, Tomoaki HORI, Satoru UENO, Yukinobu KOYAMA, Shuji ABE

    Japan Geoscience Union 2014     2014.4

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  59. Contribution of the IUGONET data analysis system to upper atmospheric researches

    Atsuki SHINBORI, Manabu YAGI, Yoshimasa TANAKA, Yuka SATO, Akiyo YATAGAI, Norio UMEMURA, Tomoaki HORI, Satoru UENO, Yukinobu KOYAMA, Shuji ABE

    Japan Geoscience Union 2014     2014.4

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  60. 地磁気日変化に見られる超高層大気の長期変動

    新堀 淳樹, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一, 谷田貝亜紀代

    日本地球惑星科学連合大会2014     2014.4

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  61. 磁気嵐時の地磁気変動に見られるグローバルな電離圏電流分布について

    新堀淳樹, 堀智昭, 田中良昌, 小山幸伸, 菊池崇, 長妻努

    日本地球惑星科学連合大会2014     2014.4

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  62. 磁気嵐時における地磁気変動に見られるグローバルな電離圏電流分布について

    新堀淳樹, 堀智昭, 田中良昌, 小山幸伸, 菊池崇, 長妻努

    平成25年度名古屋大学太陽地球環境研究所研究集会「太陽地球環境メタデータ・データベースによる時空間変動の学際研究」     2014.3

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  63. 磁気嵐時の地磁気変動に見られる電離圏電流分布について

    新堀淳樹, 堀智昭, 田中良昌, 小山幸伸, 菊池崇, 長妻努

    電磁圏シンポジウム     2014.3

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  64. Global distributions of storm-time ionospheric currents as seen in geomagnetic field variations Reviewed

    Shinbori, A, T. Hori, Y. Tanaka, Y. Koyama, T. Kikuchi, T. Nagatsuma

    Advances in Polar Science, 24, 296-314, doi:10.3724/SP.J.1085.2013.00296   Vol. 24   page: 296-314   2013.12

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  65. Analysis software for upper atmospheric data developed by the IUGONET project and its application to polar science Reviewed

    Tanaka, Y.-M, A. Shinbori, T. Hori, Y. Koyama, S. Abe, N. Umemura, Y. Sato, M. Yagi, S. UeNo, A. Yatagai, Y. Ogawa, Y. Miyoshi

    Advances in Polar Science, 24, 231-240, doi:10.3724/SP.J.1085.2013.00231     page: .   2013.12

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  66. 全球地磁気データから推察される磁気嵐時の電離圏電流分布の時間・空間変動

    新堀淳樹, 堀智昭, 田中良昌, 小山幸伸, 菊池崇, 長妻努

    第4回極域科学シンポジウム     2013.11

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  67. 地磁気変動に見られる磁気嵐時のグローバルな電離圏電流分布

    新堀淳樹, 堀智昭, 田中良昌, 小山幸伸, 菊池崇, 長妻努

    地球電磁気・地球惑星圏学会 第134回総会及び講演会     2013.11

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  68. Characteristics of long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet (Sq) daily variation

    Shinbori, A, Y. Koyama, M. Nose, T. Hori, Y. Otsuka, A. Yatagai

    International CAWSES-II Symposium     2013.11

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  69. IUGONET プロジェクトチーム, "地磁気日変動の振幅から推察される超高層大気の長期変動について

    新堀淳樹, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一, 谷田貝亜紀代

    平成25年度国立極地研究所研究集会     2013.8

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  70. IUGONETデータ解析システム(MDDB/UDAS)が切り開くサイエンス

    新堀淳樹, 八木学, 田中良昌, 佐藤由佳, 堀智昭, 上野悟, 小山幸伸, 谷田貝亜紀代, 阿部修司, IUGONET, プロジェクトチーム

    平成25年度国立極地研究所研究集会     2013.8

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  71. Contribution of the IUGONET Data Exchange System and Data Analysis Software to Space Weather and Climatology Researches Reviewed

    Shinbori, A, N. V. Rao, T. Tsuda

    Asia Oceania Geoscience Society 2013     2013.6

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  72. 磁気赤道-低緯度域における磁気急始(SC)の磁場振幅の季節変化について

    新堀淳樹, 小山幸伸, 菊池崇, 荒木徹, 池田昭大, 魚住禎司, Rola, Emerito S. Otadoy, 歌田久司, 長妻努, 湯元清文

    日本地球惑星科学連合2013年大会     2013.5

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  73. 地磁気静穏日変化に見られる超高層大気の長期変動について

    新堀淳樹, 小山幸伸, 能勢正仁, 谷田貝亜紀代, 堀智昭, 大塚雄一

    日本地球惑星科学連合2013年大会     2013.5

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  74. IUGONETメタデータ登録・管理システムの処理性能評価 Reviewed

    堀智昭, 梅村宜生, 阿部修司, 小山幸伸, 田中良昌, 林寛生, 林寛生, 上野悟, 新堀淳樹, 佐藤由佳, 八木学

    宇宙航空研究開発機構研究開発報告 JAXA-RR-   ( 12-006 ) page: 71-78   2013.3

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    J-GLOBAL

  75. Current status and future development of IUGONET data analysis software Reviewed

    Tanaka Yoshimasa, Shinbori Atsuki, Umemura Norio, Hori Tomoaki, Abe Shuji, Koyama Yukinobu, Hayashi Hiroo, Ueno Satoru, Sato Yuka, Yatagai Akiyo, Ogawa Yasunobu, Miyoshi Yoshizumi, Seki Kanako, Miyashita Yukinaga, Segawa Tomonori

    JAXA research and development report   Vol. 12 ( 12-006 ) page: 63-70   2013.3

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    In the IUGONET (Inter-university Upper atmosphere Global Observation NETwork) project, we have developed UDAS (iUgonet Data Analysis Software), which is a software to visualize and analyze various kinds of upper atmospheric data distributed by five universities/institutes (Tohoku Univ., Nagoya Univ., Kyoto Univ., Kyushu Univ., and NIPR). UDAS is a plug-in software of TDAS (THEMIS Data Analysis Software suite) written in IDL (Interactive Data Language), and thus can call useful routines to visualize and analyze time series data and GUI included in TDAS. We released a beta version of UDAS at the IUGONET website in May, 2011, and a formal version in February, 2012. We are planning to incorporate UDAS into TDAS and release it from the THEMIS software website after September, 2012. Automatic test tools for the UDAS programs were developed to reduce the workload for the development team. Furthermore, we built an executable file of TDAS that can run on the IDL Virtual Machine environment without any IDL licenses and released it for public testing. These developments will contribute to the promotion of the use of the UDAS and the ground-based observational data distributed by the IUGONET institutions.

    J-GLOBAL

  76. IUGONETメタデータデータベース、および統計解析システムを用いた太陽地球環境変動の研究

    新堀淳樹, 田中良昌, 浜口良太, 堀智昭, 小山幸伸, 阿部修司, 佐藤由佳

    H24太陽地球環境研究所研究集会「緯度間結合の大気科学」     2013.3

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  77. 地磁気日変化に見られる超高層大気の長期変動について

    新堀淳樹, 浜口良太, 小山幸伸, 能勢正仁, 堀智昭, 大塚雄一, 谷田貝亜紀代

    電磁圏物理学シンポジウム     2013.3

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  78. 地磁気静穏日変化の長期変動について

    新堀淳樹, 浜口良太, 小山幸伸, 能勢正仁, 谷田貝亜紀代, 堀智昭, 大塚雄一, 浅井歩, 上野悟, 磯部洋明, 横山正樹

    太陽研究シンポジウム「活動極大期の太陽研究、そして新たな太陽研究への布石」     2013.2

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  79. D154 IUGONETメタデータデータベース(気象研究のための気象観測データベースの発表,専門分科会)

    谷田貝 亜紀代, 小山 幸伸, 堀智 昭, 阿部 修司, 田中 良昌, 新堀 淳樹, 梅村 宜生, 上野 悟, 佐藤 由佳, 八木 学, 橋口 典子

    大会講演予講集   Vol. 103   page: 164 - 164   2013

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  80. 太陽活動と高層大気の長期変化(地球側)

    新堀淳樹, 林寛生, 上野悟, 磯部洋明, 浅井歩, 横山正樹

    第160回生存圏シンポジウム 第3回宇宙環境・利用シンポジウム「太陽活動と地球・惑星大気」     2012.12

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  81. Evolution of negative SI-induced ionospheric flows observed by SuperDARN King Salmon HF radar Reviewed

    T. Hori, A. Shinbori, N. Nishitani, T. Kikuchi, S. Fujita, T. Nagatsuma, O. Troshichev, K. Yumoto, A. Moiseyev, K. Seki

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 117 ( 12 )   2012.12

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    The spatial evolution of vortex-like flow structures induced by a negative sudden impulse (SI-) is studied on the basis of SuperDARN King Salmon HF radar (KSR) with other ground and satellite data. A large dip in the solar wind density induced a fairly large SI- with a SYM-H amplitude of similar to 40 nT. The SI- induced ionospheric flow signatures in the evening sector (MLT similar to 19 h) were observed by KSR as a westward flow associated with the preliminary impulse (PI) followed by a more intense eastward flow with the main impulse (MI) in the sub-auroral region of the magnetic latitude similar to 60-70 deg, consistent with the local ground magnetic field observations. Following the first PI-MI flow sequence, KSR saw a second and possibly third sequence of flow variation which were much smaller in flow amplitude than the first pair but showed qualitatively very similar flow variations and latitudinal/longitudinal propagation characteristics. These observations can be interpreted as aftershocks of the first PI-MI; the same sequence of vortices and field-aligned currents were generated and then drifted anti-sunward with the same mechanism, namely the pumping motion of the dayside magnetosphere. These results are qualitatively consistent with predictions suggested by recent numerical simulations. Citation: Hori, T., A. Shinbori, N. Nishitani, T. Kikuchi, S. Fujita, T. Nagatsuma, O. Troshichev, K. Yumoto, A. Moiseyev, and K. Seki (2012), Evolution of negative SI- induced ionospheric flows observed by SuperDARN King Salmon HF radar, J. Geophys. Res., 117, A12223, doi:10.1029/2012JA018093.

    DOI: 10.1029/2012JA018093

    Web of Science

  82. 磁気嵐時の地磁気変動に見られるグローバルな電離圏電場と電流分布について

    新堀淳樹, 田中良昌, 辻裕司, 菊池崇, 小山幸伸, 長妻努, 冨川喜弘, 堤雅基

    第3回極域科学シンポジウム/第36回極域宙空圏シンポジウム     2012.11

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  83. Storm-time electron density enhancement in the cleft ion fountain Reviewed

    N. Kitamura, Y. Nishimura, M. O. Chandler, T. E. Moore, N. Terada, T. Ono, A. Shinbori, A. Kumamoto

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 117 ( 11 )   2012.11

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    To determine the characteristics and origin of observed storm-time electron density enhancements in the polar cap, and to investigate the spatial extent (noon-midnight direction) of associated O+ ion outflows, we analyzed nearly simultaneous observations of such electron density enhancements from the Akebono satellite and ion upflows from the Polar satellite during a geomagnetic storm occurring on 6 April 2000. The Akebono satellite observed substantial electron density enhancements by a factor of similar to 10-90 with a long duration of similar to 15 h at similar to 2 R-E in the southern polar region. The Polar satellite outflow measurements in the northern polar cap at similar to 7-4 R-E exhibited velocity filtering of the similar to 100 eV to similar to 0 eV (from the spacecraft potential) ion outflow from the cleft ion fountain, with resultant temperatures declining from similar to 3 eV to 0.03 eV with increasing distance from the cusp. Similar velocity filtering was detected in the southern polar cap at similar to 1.8-3.5 RE. The region of O+ ion outflows with fluxes exceeding 5 x 10(8) /cm(2)/s (mapped to 1000 km altitude) extended similar to 10 degrees MLAT (similar to 1000 km) at the ionosphere from the cusp/cleft into the dayside polar cap at similar to 2.5 RE. These coordinated Akebono-Polar observations are consistent with the development of storm-time electron density enhancements in the polar cap as a result of the bulk outflow of low-energy plasma as part of the cleft ion fountain. The large spatial scale, large ion fluxes, and the long duration indicate significant supply of very-low-energy O+ ions to the magnetosphere through this region.

    DOI: 10.1029/2012JA017900

    Web of Science

  84. Effect of R2-FAC development on the ionospheric electric field pattern deduced by a global ionospheric potential solver Reviewed

    Nakamizo, A, Y. Hiraki, Y. Ebihara, T. Kikuchi, K. Seki, T. Hori, A. Ieda, Y. Miyoshi, Y. Tsuji, T. Nishimura, A. Shinbori

    J. Geophys. Res.   Vol. 117   page: A09231   2012.9

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    DOI: 10.1029/2012JA017669

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  85. IUGONETプロダクトを用いた太陽風-磁気圏-電離圏-大気圏結合の研究

    新堀淳樹, 八木学, 田中良昌, 佐藤由佳, 堀智昭, 上野悟, 小山幸伸, 能勢正仁, 谷田貝亜紀代, 橋口典子, 阿部修司, IUGONET, プロジェク トチーム

    第8回磁気圏-電離圏複合系における対流に関する研究会プログラム     2012.9

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  86. Upper atmospheric research using the metadata database and integrated data analysis software (UDAS) developed by the IUGONET project Reviewed

    Shinbori, A, Y. Koyama, T. Hori, Y. Tanaka, S. Abe, S. UeNo, N. O. Hashiguchi, N. Umemura, Y. Sato, M. Yagi, A. Yatagai, IUGONET project team

    HSS2012     2012.8

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  87. IUGONET プロジェクトチーム, "IUGONETプロダクトを用いた電離圏・熱圏・中間圏研究

    新堀淳樹, 八木学, 田中良昌, 佐藤由佳, 堀智昭, 上野悟, 小山幸伸, 谷田貝亜紀代, 橋口典子, 阿部修司

    電離圏・熱圏・中間圏研究会     2012.8

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  88. Magnetic local time and latitude dependence of amplitude of the main impulse (MI) of geomagnetic sudden commencements and its seasonal variation Reviewed

    Atsuki Shinbori, Yuji Tsuji, Takashi Kikuchi, Tohru Araki, Akihiro Ikeda, Teiji Uozumi, Dmitry Baishev, Boris M. Shevtsov, Tsutomu Nagatsuma, Kiyohumi Yumoto

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 117 ( 8 )   2012.8

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    The magnetic local time and latitude dependence of amplitude of the main impulse (MI) of geomagnetic sudden commencements (SCs) and its seasonal variation have been investigated using high time resolution (1-3 sec) geomagnetic data in the latitudinal range 27-70 degrees for the period 1996-2010. The daytime distribution of the SC-MI amplitude in the sub-auroral and middle latitudes (35-60 degrees) is similar to the DP-2 type geomagnetic variation which shows negative and positive changes in the morning and afternoon, respectively. The magnetic field variation is reversed around the magnetic latitude of 63-65 degrees. This suggests that a pair of field-aligned currents (FACs), resembling the region-1 (R-1) FACs, is located near the magnetic latitude of 63-65 degrees. The nighttime SC amplitude is enhanced significantly in the low and middle latitudes (27-60 degrees). The enhancement is due to the magnetic effect produced by the SC-MI FACs. In the nighttime auroral latitude (63-65 degrees), the SC amplitude decreases steeply due to the enhanced westward auroral electrojet associated with the compression of the magnetosphere. The size of the diurnal variation tends to increase significantly during the summer, compared with that during the winter. This seasonal variation suggests that the DP-2 type ionospheric currents (ICs) and FACs generated during the SC-MI phase are intensified by increased ionospheric conductivities during the summer. It can be concluded that the large-scale MI current system in the ionosphere and magnetosphere is voltage generator.

    DOI: 10.1029/2012JA018006

    Web of Science

  89. IUGONETサイエンスタスクチームの活動報告

    新堀淳樹, 八木学, 田中良昌, 佐藤由佳, 堀智昭, 上野悟, 小山 幸伸, 谷田貝亜紀代, 阿部修司, IUGONETプロジェクトチーム

    平成24年度IUGONET中間報告会     2012.8

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  90. Magnetic latitude and local time distributions of ionospheric currents during a geomagnetic storm Reviewed

    Yuji Tsuji, Atsuki Shinbori, Takashi Kikuchi, Tsutomu Nagatsuma

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 117 ( 7 )   2012.7

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    In order to clarify the global distribution of ionospheric currents during a geomagnetic storm, we analyzed ground magnetic disturbances from high latitudes to the magnetic equator for the storm on September 7-8, 2002, with the minimum SYM-H value of -168 nT. In this analysis, we investigated magnetic field deviations in the northward component from the SYM-H, as functions of the dipole magnetic latitude (DMLAT) and the magnetic local time (MLT). During the main phase of the storm, the deviations at the low latitudes (10 degrees-35 degrees in DMLAT) were positive/negative in the dawn/dusk (0-9/11-24 h MLT) sector. On the other hand, the deviations at the dayside middle latitudes (35 degrees-55 degrees in DMLAT) were negative/positive in the morning/afternoon (6-12/13-15 h MLT) sector. The local time distribution at the low latitudes may represent the dawn-dusk asymmetry of the storm time ring current, while that at the dayside middle latitudes coincides with the DP2 currents due to the convection electric field associated with the Region 1 field-aligned currents (R1 FACs). All over the nightside middle latitude, the deviations were positive. This implies the direct effect of the R1 FACs through the Biot-Savart's law. At the geomagnetic equator, the eastward and westward electrojets were intensified on the day and nightside, respectively, being caused by the penetrated dawn-to-dusk convection electric field. We found that the MLT distribution of the magnetic deviations during the recovery phase was in opposite sense to that during the main phase at the dayside middle latitudes. The reversed magnetic disturbances must be due to the overshielding electric field associated with the Region 2 field-aligned currents (R2 FACs). Similarly, the deviations at the dayside and nightside equator were reversed, indicating penetration of the dusk-to-dawn overshielding electric field into the equatorial ionosphere. Based on the above results, we propose a current system including the ionospheric currents at middle latitudes caused by the R1/R2 FACs, equatorial EEJ/CEJ, and asymmetric ring current, during the main/recovery phase of the geomagnetic storm.

    DOI: 10.1029/2012JA017566

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  91. Temporal and spatial evolution of ionospheric currents and electric fields during a geomagnetic storm

    Shinbori, A, Y. Nishimura, Y. Tsuji, T. Kikuchi, T. Nagatsuma, IUGONET project team

    GEM Workshop 2012     2012.6

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  92. IUGONET プロジェクトチーム, "地磁気静穏日変化(Sq)の長期トレンドから推察される超高層大気変動について

    新堀淳樹, 小山幸伸, 能勢正仁, 林寛生, 堀智昭, 大塚雄一, 浅井歩, 磯部洋明, 横山正樹, 上野悟, 塩田大幸, 羽田裕子, 北井礼三郎, 津田敏隆

    日本地球惑星科学連合2012年大会     2012.5

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  93. 大学間連携プロジェクト「超高層大気長期変動の全球地上ネットワーク観測・研究」 Reviewed

    林寛生, 小山幸伸, 堀智昭, 田中良昌, 新堀淳樹, 鍵谷将人, 阿部修司, 河野貴久, 吉田大紀, 上野悟, 金田直樹, 米田瑞生, 田所裕康, 元場哲郎

    宇宙航空研究開発機構研究開発報告 JAXA-RR-   ( 11-007 ) page: 113-120   2012.3

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  94. IUGONET共通メタデータフォーマットの策定とメタデータ登録管理システムの開発 Reviewed

    堀智昭, 鍵谷将人, 田中良昌, 林寛生, 上野悟, 吉田大紀, 阿部修司, 小山幸伸, 河野貴久, 金田直樹, 新堀淳樹, 田所裕康, 米田瑞生

    宇宙航空研究開発機構研究開発報告 JAXA-RR-   ( 11-007 ) page: 105-111   2012.3

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  95. 超高層物理学分野の為のメタデータ・データベースの開発 Reviewed

    小山幸伸, 河野貴久, 堀智昭, 阿部修, 吉田大紀, 林寛生, 田中良昌, 新堀淳樹, 上野悟, 金田直樹, 米田瑞生, 元場哲郎, 鍵谷将人, 田所裕康

    宇宙航空研究開発機構研究開発報告 JAXA-RR-   ( 11-007 ) page: 99-104   2012.3

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  96. IUGONET解析ソフトウェアの開発 Reviewed

    田中良昌, 新堀淳樹, 鍵谷将人, 堀智昭, 阿部修司, 小山幸伸, 林寛生, 吉田大紀, 河野貴久, 上野悟, 金田直樹, 米田瑞生, 田所裕康, 元場哲郎, 三好由純, 関華奈子, 宮下幸長, 瀬川朋紀, 小川泰信

    宇宙航空研究開発機構研究開発報告 JAXA-RR-   ( 11-007 ) page: 91-98   2012.3

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  97. 平成24年度のIUGONETサイエンスタスクチームの活動報告と地磁気日変化の振幅に見られる超高層大気の長期変動

    新堀淳樹, 小山幸伸, 林寛生, 能勢正仁, 大塚雄一, 堀智昭, IUGONET, プロジェクトチーム

    名古屋大学太陽地球環境研究所研究集会「地球科学メタ情報データベースの現状とその活用」     2012.2

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  98. Long-term Variation in the Upper Atmosphere as Seen in the Amplitude of the Geomagnetic Solar Quiet Daily Variation

    Shinbori, A, Y. Koyama, H. Hayashi, M. Nose, T. Hori, Y. Otsuka, T. Tsuda, H. Hiroo, IUGONET Project Team

    The 2nd Nagoya Workshop on the Relationship between Solar Activity and Climate Changes     2012.1

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  99. 太陽活動と地磁気静穏日変化との長期的な関係について

    新堀淳樹, 小山幸伸, 能勢正仁, 林寛生, 堀智昭, 大塚雄一, 浅井歩, 上野悟, 磯部洋明, 横山正樹

    太陽研究会「太陽の多角的観測と宇宙天気研究の新展開2012     2012.1

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  100. 地磁気日変化の振幅に見られる超高層大気の長期変動について

    新堀淳樹, 小山幸伸, 林寛生, 能勢正仁, 堀智昭, 大塚雄一

    第7回磁気圏電離圏複合系における対流に関する研究会集録     2012.1

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  101. P367 IUGONET「超高層大気長期変動の全球地上ネットワーク観測・研究」の紹介(ポスター・セッション)

    谷田貝 亜紀代, 堀 智昭, 田中 良昌, 小山 幸伸, 阿部 修司, 林 寛生, 新堀 淳樹, 梅村 宜生, 上野 悟, 佐藤 由佳, 八木 学

    大会講演予講集   Vol. 102   page: 541 - 541   2012

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  102. 磁気嵐時におけるグローバルな地磁気変動と電離圏擾乱ダイナモについて

    新堀淳樹, 田中良昌, 辻裕司, 菊池崇, 小山幸伸, 林寛生, 冨川喜弘, 長妻努, 堤雅基, Dennis M. Riggin, Dave C. Fritts, Peter Hoffmann, IUGONETプロジェクトチーム

    第2回極域科学シンポジウム・第35回極域宙空圏シンポジウム     2011.11

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  103. 高緯度から磁気赤道域までの磁気急始 (SC) の磁場振幅の季節変化の緯度依存性

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 池田昭大, 魚住禎司, Baishev Dmitry, Shevtsov Boris M, Otadoy Rola, E. S, 歌田久司, 長妻努, 湯元清文, IUGONETプロジェクトチーム

    地球電磁気・地球惑星圏学会 第130回講演会     2011.11

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  104. 磁気嵐時におけるグローバル地磁気変動と熱圏風変動について

    新堀淳樹, 田中良昌, 辻裕司, 菊池崇, 林寛生, 冨川喜弘, 長妻努, 堤雅基, IUGONETプロジェクトチーム

    磁気圏-電離圏複合系における対流に関する研究会     2011.9

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  105. Publication of Atmospheric Radar Observation Database at RISH, Kyoto University

    H. Hashiguchi, T. Tsuda, M. Shiotani, M. Yamamoto, T. Nakamura, H. Hayashi, J. Furumoto, M.K. Yamamoto, A. Shinbori, N.O. Hashiguchi

    The 1st ICSU World Data System Conference --- Global Data for Global Science     2011.9

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  106. [研究活動]研究トピックス: 太陽物理学との連携による超高層大気変動現象の研究

    上野 悟, 新堀 淳樹, 林 寛生, 浅井 歩, 磯部 洋明, 横山 正樹

    京都大学大学院理学研究科附属天文台年次報告   Vol. 2010   page: 27 - 28   2011.9

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  107. Solar zenith angle dependence of plasma density and temperature in the polar cap ionosphere and low-altitude magnetosphere during geomagnetically quiet periods at solar maximum Reviewed

    N. Kitamura, Y. Ogawa, Y. Nishimura, N. Terada, T. Ono, A. Shinbori, A. Kumamoto, V. Truhlik, J. Smilauer

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 116 ( 8 )   2011.8

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    We constructed an empirical model of the electron density profile with solar zenith angle (SZA) dependence in the polar cap during geomagnetically quiet periods using 63 months of Akebono satellite observations at solar maximum. The electron density profile exhibits a transition at similar to 2000 km altitude only under dark conditions. The electron density and scale height at low altitudes change drastically, by factors of 25 (at 2300 km altitude) and 2.0, respectively, as the SZA increases from 90 degrees to 120 degrees. The SZA dependence of the ion and electron temperatures is also investigated statistically on the basis of data obtained by the Intercosmos satellites and European Incoherent Scatter (EISCAT) Svalbard radar (ESR). A drastic change in the electron temperature occurs near the terminator, similarly to that in the electron density profile obtained by the Akebono satellite. The sum of the ion and electron temperatures obtained by the ESR (similar to 6500 K at similar to 1050 km altitude under sunlit conditions and similar to 3000 K at similar to 750 km altitude under dark conditions) agrees well with the scale height at low altitudes obtained from the Akebono observations, assuming that the temperature is constant and that O(+) ions are dominant. Comparisons between the present statistical results (SZA dependence of the electron density and ion and electron temperatures) and modeling studies of the polar wind indicate that the plasma density profile (especially of the O(+) ion density) in the polar cap is strongly controlled by solar radiation onto the ionosphere by changing ion and electron temperatures in the ionosphere during geomagnetically quiet periods.

    DOI: 10.1029/2011JA016631

    Web of Science

  108. Seasonal dependence of geomagnetic field variations on the ground associated with geomagnetic sudden commencements Reviewed

    Shinbori, A, Y. Tsuji, T. Kikuchi, T. Araki, A. Ikeda, T. Uozumi, S. I. Solovyev, B. M. Shevtsov, R. E, S. Otadoy, H. Utada, T. Nagatsuma, H. Hayashi, K. Yumoto, IUGONET project team

    XXV IUGG General Assembly     2011.7

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  109. IUGONET 観測データに基づく地磁気静穏日変化と熱圏風の長期変動について

    新堀淳樹, 小山幸伸, 林寛生, 能勢正仁, 津田敏隆, IUGONET, プロジェクトチーム

    日本地球惑星科学連合2011年大会     2011.5

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  110. Development of integrated analysis software of observation data in the upper atmosphere

    Shinbori, A, Y. Tanaka, M. Kagitani, H. Hayashi

    ecent Advances in Observational Studies of the Tropical Atmosphere and Ionosphere     2011.3

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  111. Long-term analysis of geomagnetic solar quiet daily (Sq) variation and neutral winds in the mesosphere and lower thermosphere (MLT) region using the IUGONET observation data

    Shinbori, A, H. Hayashi, Y. Koyama, S. Nose, S. Ueno, H. Isobe, A. Asai, M. Yokoyama

    Recent Advances in Observational Studies of the Tropical Atmosphere and Ionosphere     2011.3

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  112. 高緯度から磁気赤道域における磁気急始(SC)の磁場振幅の季節依存性について

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 池田昭大, 魚住禎司, S. I. Solovyev, Boris M. Shevtsov, Rol, Emerito S. Otadoy, 歌田久司, 長妻努, 湯元清文, IUGONETプロジェクトチーム

    名古屋大学太陽地球環境研究所・研究集会「電磁圏物理学シンポジウム」     2011.3

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  113. IUGONET観測データに基づく地磁気日変化と熱圏風の長期トレンドについて

    新堀淳樹, 林寛生, 小山幸伸, 能勢正仁, 上野悟, 磯部洋明, 浅井歩, 横山正樹

    名古屋大学太陽地球環境研究所研究集会『地球科学メタ情報データベースの現状とその活用』     2011.2

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  114. Penetration of Magnetospheric Electric Fields to the Low Latitude Ionosphere During Storm/Substorms Reviewed

    Kikuchi, T, K. K. Hashimoto, A. Shinbori, Y. Tsuji, S. Watari

    Aeronomy of the Earth's Atmosphere and Ionosphere IAGA Special Sopron Book Series 2, DOI: 10.1007/978-94-007-0326-1_34, Edit. M.A. Abdu, D.Pancheva, A. Bhattacharyya, Springer Science+Business Media B.V.   Vol. 2   page: 443-453   2011.2

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  115. IUGONETデータベースを利用した生存圏科学萌芽研究"

    新堀淳樹, 林寛生, 上野悟, 磯部洋明, 浅井歩, 横山正樹

    太陽研究会「太陽の多角的観測と宇宙天気研究の新展開2011」     2011.1

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  116. DSpaceを用いた超高層物理学のためのメタデータ・データベースの構築

    河野貴久, 小山幸伸, 堀智昭, 阿部修司, 吉田大紀, 林寛生, 新堀淳樹, 田中良昌, 鍵谷将人, 金田直樹, 田所裕康

    第3回データ工学と情報マネジメントに関するフォーラム論文集, C8-5     2011

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  117. Direct measurements of the Poynting flux associated with convection electric fields in the magnetosphere Reviewed

    Y. Nishimura, T. Kikuchi, A. Shinbori, J. Wygant, Y. Tsuji, T. Hori, T. Ono, S. Fujita, T. Tanaka

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 115 ( 12 )   2010.12

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    Observations of Poynting fluxes associated with onset of convection electric fields are essential for understanding of electromagnetic energy transport from the solar wind toward the magnetosphere leading to changes in the convection electric field, which is one of the most fundamental parameters in the magnetosphere-ionosphere coupled system. We present Cluster multispacecraft observations of Poynting fluxes associated with abrupt changes in large-scale electric fields during sudden commencements and southward turning of the interplanetary magnetic field (IMF). The Cluster spacecraft detected Poynting fluxes dominated by the field-aligned upward component during the preliminary impulse of sudden commencements and in the initial period after southward turning of the IMF. The upward Poynting flux indicates existence of Alfven waves transporting electromagnetic energy from the ionosphere toward the magnetosphere leading to magnetospheric convection changes. The waveguide model and global magnetohydrodynamic (MHD) simulation calculating evolution of the Poynting flux following solar wind pressure enhancements also show upward Poynting fluxes propagating from the ionosphere toward the magnetosphere faster than the propagation of compressional waves. We conclude that the ionosphere acts as a channel to transmit electromagnetic energy supplied as field-aligned currents toward a wide region in the magnetosphere-ionosphere system instantaneously, leading to changes in magnetospheric convection electric fields.

    DOI: 10.1029/2010JA015491

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  118. 磁気嵐時におけるグローバルな地磁気変動

    新堀淳樹, 西村幸敏, 辻裕司, 菊池崇, 長妻努, 亘慎一, IUGONETメンバー

    第34回極域宙空圏シンポジウム     2010.12

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  119. Observations of very-low-energy (&lt; 10 eV) ion outflows dominated by O+ ions in the region of enhanced electron density in the polar cap magnetosphere during geomagnetic storms Reviewed

    N. Kitamura, Y. Nishimura, T. Ono, Y. Ebihara, N. Terada, A. Shinbori, A. Kumamoto, T. Abe, M. Yamada, S. Watanabe, A. Matsuoka, A. W. Yau

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 115 ( 11 )   2010.11

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    Velocity distributions of upflowing ions in the polar ionosphere are crucial to understand their destinations. Natural plasma wave observations by the plasma wave and sounder experiments and thermal ion observations by the suprathermal ion mass spectrometer onboard the Akebono satellite at similar to 9000 km altitude in the polar magnetosphere during the geomagnetic storms showed that ions in the region of enhanced electron density in the polar cap were dominated by very-low-energy O+ ions (similar to 85%) with upward velocities of 4-10 km s(-1), corresponding to streaming energies of 1.3-8.4 eV. The fluxes of very-low-energy upflowing O+ ions exceeded 1 x 10(9) cm(-2) s(-1) (mapped to 1000 km altitude) across wide regions. These signatures are consistent with high-density plasma supplied by the cleft ion fountain mechanism. Trajectory calculations of O+ ions based on the Akebono observations as the initial condition showed the transport paths and accelerations of the O+ ions and indicated that the velocities of the very-low-energy upflowing O+ ions through the dayside polar cap are enough to reach the magnetosphere under strong convection. The calculations suggest the importance of the very-low-energy upflowing O+ ions with large fluxes in the total O+ ion supply toward the magnetosphere, especially the near-Earth tail region and inner magnetosphere. The initially very-low-energy O+ ions can contribute significantly to the ring current formation during geomagnetic storms since some of the O+ ions were transported into the ring current region with typical energies of ring current ions (several tens of keV) in the trajectory calculations.

    DOI: 10.1029/2010JA015601

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  120. IUGONET観測データに基づく赤道域における磁気急始(SC)の磁場振幅の季節依存性

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 林寛生, 津田敏隆, 池田昭大, 魚住禎司, R. E, S. Otadoy, 歌田久司, B. M. Shevtsov, S. I. Solovyev, 長妻努, 湯元清文, IUGONETプロジェクトチーム

    平成22年度・第1回STE(太陽地球環境)現象報告会     2010.10

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  121. Anomalous Enhancement of Occurrence of the Preliminary Impulse of Geomagnetic Sudden Commencement (SC) at Low Latitude in the South Atlantic Anomaly (SAA) region Reviewed

    Shinbori A, Y. Nishimura, Y. Tsuji, T. Kikuchi, T. Araki, A. Ikeda, T. Uozumi, R. Otadoy, H. Utada, J. Ishitsuka, N. Trivedi, S. Dutra, N. Schuch, S. Watari, T. Nagatsuma, K. Yumoto

    Journal of Geophysical Research: Space Physics, Volume 115, Issue A8, CiteID: A08309, doi: 10.1029/2009JA015035   Vol. 115 ( A8 ) page: .   2010.8

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  122. Characteristics of enhanced convection electric field in the inner magnetosphere associated with sudden commencements observed by the Akebono Satellite Reviewed

    Shinbori, A, Y. Nishimura, T. Kikuchi, T. Araki, A. Matsuoka, Y. Tsuji

    38th COSPAR Scientific Assembly     2010.7

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  123. ブラジル磁気異常帯における磁気急始(SC)時の初期インパルスの異常な出現特性について

    2010年大会     2010.5

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  124. 磁気嵐時におけるグローバル地磁気変動

    新堀 淳樹, 西村幸敏, 辻裕司, 菊池崇, 長妻努, 亘慎一

    日本地球惑星科学連合2010大会     2010.5

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  125. Penetration of magnetospheric electric fields to the equator and their effects on the low-latitude ionosphere during intense geomagnetic storms Reviewed

    B. Veenadhari, S. Alex, T. Kikuchi, A. Shinbori, Rajesh Singh, E. Chandrasekhar

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 115 ( A3 )   2010.3

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    The penetration of magnetospheric electric fields to the magnetic equator has been investigated for two intense magnetic storms that occurred on 31 March 2001 and 6 November 2001. The digital ground magnetic data from equatorial station Tirunelveli (TIR, 0.17 degrees S geomagnetic latitude (GML)) and low-latitude station Alibag (ABG, 10.17 degrees N GML) have been used to identify the storm time electrojet index, EEJ(Dis), which is the difference of the magnetic field variations between TIR and ABG after removing the quiet day variations. The appearance of enhanced DP 2 currents and counterelectrojets (CEJ) during the main and recovery phases of the magnetic storms is possibly due to prompt penetration of electric fields from the high latitudes. These signatures can be interpreted as a clear indicator of the eastward and westward electric fields at the equator. The observed results suggest that the magnitude of the equatorial ionospheric currents driven by the penetrating electric fields is very sensitive to ionospheric conductivity (which depends on local time). Moreover, the intensity of the DP 2 currents started decreasing during the end of the main phase of the storm despite the large negative southward IMF Bz, indicating the dominance of a well-developed shielding electric field for 1 h. As an effect of penetrating electric fields at the equator, the equatorial ionization anomaly is enhanced during the main phase (because of strong eastward electric field) and is inhibited or reduced due to the strong CEJ (because of westward electric field) during the recovery phase.

    DOI: 10.1029/2009JA014562

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  126. 磁気嵐時におけるグローバル地磁気変動について

    新堀淳樹, 西村幸敏, 辻裕司, 菊池崇, 荒木徹, 長妻努, 亘慎一

    平成21年度・第2回STE(太陽地球環境)現象報告会     2010.3

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  127. 南米磁気異常帯の低緯度における磁気急始 (SC) 時の初期インパルスの出現増大について

    新堀淳樹, 辻裕司, 西村幸敏, 菊池崇, 荒木徹, 池田昭大, 魚住禎司, Roland E. S. Otadoy, 歌田久司, Jose Ishitsuka・Nalin Baulal Trivedi, Severino L. G. Dutra, Nelson Jorge Schuch, 亘慎一, 長妻努, 湯元清文

    電磁圏物理学シンポジウム     2010.3

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  128. 現実に即した高さ方向の電気伝導度の導出法の開発

    新堀淳樹, 西村幸敏, 海老原祐輔, 菊池崇, 平木康隆, 堀智昭

    GEMSIS-M,I ワークショップ「実証型ジオスペースモデリングに向けて」     2010.2

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  129. 磁気嵐時のグローバル電流系と地磁気変動

    新堀淳樹, 西村幸敏, 辻裕司, 菊池崇, 海老原祐輔, 長妻努, 亘慎一

    GEMSIS-M,I ワークショップ「実証型ジオスペースモデリングに向けて」     2010.2

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  130. SZA dependence of the plasma density and temperature in the polar ionosphere-magnetosphere during quiet periods at solar maximum

    KITAMURA NARITOSHI, TERADA NAOKI, OGAWA YASUNOBU, ABE TAKUMI, ONO TAKAYUKI, NISHIMURA YUKITOSHI, SHINBORI ATSUKI, KUMAMOTO ATSUSHI

    極域科学・宙空圏・気水圏・生物・地学シンポジウム講演予稿集(CD-ROM)   Vol. 2010   page: ROMBUNNO.UO030   2010

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  131. 太陽風IMFの方位に対するSC振幅の日変化の依存性

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 池田昭大, 魚住禎司, 亘慎一, 長妻努, 湯元清文

    平成21年度名古屋大学太陽地球環境研究所研究集会「第5回磁気圏-電離圏複合系における対流に関する研究会」     2009.11

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  132. 多圏間相互作用に対する太陽風動圧の役割

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 池田昭大, 魚住禎司, 湯元清文

    STE研究連絡会現象解析ワークショップ~システムとしての磁気嵐・サブストーム~     2009.10

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  133. Response of convection electric fields in the magnetosphere to IMF orientation change Reviewed

    Y. Nishimura, T. Kikuchi, J. Wygant, A. Shinbori, T. Ono, A. Matsuoka, T. Nagatsuma, D. Brautigam

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 114 ( 9 )   2009.9

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    The transient response of convection electric fields in the inner magnetosphere to southward turning of the interplanetary magnetic field (IMF) is investigated using in-situ electric field observations by the CRRES and Akebono spacecraft. Electric fields earthward of the inner edge of the electron plasma sheet show quick responses simultaneously with change in ionospheric electric fields, which indicates the arrival of the first signal related to southward turning. A coordinated observation of the electric field by the CRRES and Akebono spacecraft separated by 5 RE reveals a simultaneous increase in the dawn-dusk electric field in a wide region of the inner magnetosphere. A quick response associated with the southward turning of the IMF is also identified in in-situ magnetic fields. It indicates that the southward turning of the IMF initiates simultaneous (less than 1 min) enhancements of ionospheric electric fields, convection electric fields in the inner magnetosphere, and the ring or tail current and region 2 FACs. In contrast, a quick response of convection electric fields is not identified in the electron plasma sheet. A statistical study using 161 events of IMF orientation change in 1991 confirms a prompt response within 5 min for 80% of events earthward of the electron plasma sheet, while a large time lag of more than 30 min is identified in electric fields in the electron plasma sheet. The remarkable difference in the response of electric fields indicates that electric fields in the electron plasma sheet are weakened by high conductance in the magnetically conjugated auroral ionosphere.

    DOI: 10.1029/2009JA014277

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  134. 中緯度から低緯度における磁気急始 (SC) の振幅の日変化の季節依存性

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 亘慎一

    日本地球惑星科学連合2009年大会     2009.5

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  135. サブオーロラ帯から磁気赤道における磁気急始(SC)に伴う地上磁場変動の特徴とその解釈について

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 亘慎一

    日本地球惑星科学連合2009年大会, 招待講演     2009.5

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  136. Magnetic latitude and local time dependence of the amplitude of geomagnetic sudden commencements Reviewed

    Atsuki Shinbori, Yuji Tsuji, Takashi Kikuchi, Tohru Araki, Shinichi Watari

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 114 ( 4 )   2009.4

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    Statistical analysis of the main impulse (MI) amplitude of geomagnetic sudden commencements (SCs) in a region from the middle latitudes to equator has been made using the long-term geomagnetic field data obtained from the Yap (geomagnetic latitude, theta = 0.38 degrees), Guam (theta = 5.22 degrees), Okinawa (theta = 16.54 degrees), Kakioka (theta = 27.18 degrees), Memanbetsu (theta = 35.16 degrees), and St. Paratunka (theta = 45.58 degrees) stations. The magnetic local time (MLT) dependence of SC amplitude in the middle latitudes showed magnetic field variations produced by two-cell ionospheric currents (DP 2-type currents) which are driven by the dawn-to-dusk electric field accompanying a pair of field-aligned currents (FACs). The effect of the DP 2-type currents at least expands to the low latitude (theta = 16.54 degrees). In this region, the DL part of SC produced by the enhanced Chapman-Ferraro currents can be dominant, but the DP part of SC contaminated 7% of the DL one. On the other hand, at the daytime equator between 8: 00 and 16: 00 (MLT), the SC amplitude is considerably enhanced with its peak amplitude of 3.24 ( normalized SYM-H value) around 11: 00 (MLT) due to the Cowling effect. Another interesting point is that the SC amplitude in the nighttime sector was enhanced at all the stations again, and its peak value increases with increasing magnetic latitude. This result suggests that the effect of the FACs associated with the MI phase of SC expands to the equator.

    DOI: 10.1029/2008JA013871

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  137. 低緯度ブラジル磁気異常帯における磁気急始(SC)の磁場振幅の異常増加について Reviewed

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 亘慎一, M. A. Abdu

    平成20年度・第2回STE(太陽地球環境)現象報告会     2009.3

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  138. サブオーロラ帯から磁気赤道にいたる磁気急始(SC)における磁場振幅の季節依存性について

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 亘慎一

    平成20年度名古屋大学太陽地球環境研究所研究集会「電磁圏物理学シンポジウム」     2009.3

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  139. Seasonal variations of the electron density distribution in the polar region during geomagnetically quiet periods near solar maximum Reviewed

    N. Kitamura, A. Shinbori, Y. Nishimura, T. Ono, M. Iizima, A. Kumamoto

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 114 ( 1 )   2009.1

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    Meridional electron density distributions above 45 degrees invariant latitude (ILAT) during geomagnetically quiet periods are statistically studied. Electron density data were obtained from plasma waves observed by the Akebono satellite from March 1989 to February 1991 (near solar maximum) in an altitude range of 274-10,500 km. Field-aligned electron density profiles were fitted by the sum of exponential and power law functions. The transition height, where the power law term equals the exponential term, is highest in the summer (at low solar zenith angle (SZA)) at similar to 4000 km and lowest in the winter (at high SZA) at similar to 1800 km in a region of ILAT &gt;= 70 degrees; this is caused by the larger scale height in the summer (similar to 550 km) than that in the winter (similar to 250 km). The largest seasonal variation and SZA dependence of the electron density are found at an altitude of similar to 2000 km with a factor of similar to 50 (similar to 10(4) /cc in the summer, similar to 10(3) /cc in the winter) in the trough, auroral, and polar cap regions. The seasonal variation and SZA dependence are smaller, about a factor of 5-10, above similar to 5000 km. Day-night asymmetries in each season (within a factor of 5) are smaller than the seasonal variation. The scale height is larger in the dayside than in the nightside in each season. These results indicate that photoionization processes in the ionosphere strongly control electron density distributions up to at least similar to 5000 km in the trough, auroral, and polar cap regions.

    DOI: 10.1029/2008JA013288

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  140. IMF/太陽風動圧変動時の内部磁気圏-電離圏電磁結合

    菊池崇, 橋本久美子, 海老原祐輔, 新堀淳樹, 亘慎一

    第5回磁気圏-電離圏複合系における対流に関する研究会抄録, 1-6     2009

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  141. ブラジル磁気異常帯における磁気急始(SC)時の磁場変動の特異性と電離圏電気伝導度との関係

    新堀淳樹, 辻裕司, 西村幸敏, 菊池崇, 荒木徹, 池田昭大, 魚住禎司, Rola, d, E. S. Otadoy, 歌田久司, Jose Ishitsuka, Nalin Baulal Trivedi, Severino L, G. Dutra, Nelson Jorge・Schuch, 亘慎一, 長妻務, 湯元清文

    第5回磁気圏―電離圏複合系における対流に関する研究会収録, 30-55     2009

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  142. 地磁気DP2型変動の考察

    荒木徹, 菊池崇, 新堀淳樹, 湯元清文

    第5回磁気圏-電離圏複合系における対流に関する研究会抄録, 117-124     2009

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  143. Solar zenith angle dependence of the electron density profile in the polar region during geomagnetically quiet periods

    KITAMURA NARITOSHI, TERADA NAOKI, OGAWA YASUNOBU, NISHIMURA YUKITOSHI, SHINBORI ATSUKI, ONO TAKAYUKI, KUMAMOTO ATSUSHI

    地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)   Vol. 126th   page: ROMBUNNO.B006-P022   2009

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  144. 地磁気DP2型変動の再考

    荒木徹, 菊池崇, 新堀淳樹, 湯元清文

    地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)   Vol. 126th   page: ROMBUNNO.B010-11   2009

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  145. 磁気嵐急始(SC)に伴う磁場変動から理解できること

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 亘慎一

    平成20年度名古屋大学太陽地球環境研究所研究集会「第4回磁気圏-電離圏複合系における対流に関する研究会」     2008.11

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  146. 磁気嵐時における内部磁気圏電場構造について

    新堀淳樹, 菊池崇, 西村幸敏, 辻裕司, 松岡彩子

    太陽から地球までシンポジウム     2008.10

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  147. あけぼの衛星観測に基づく磁気急始(SC)に伴う磁気圏対流電場の増大について

    新堀淳樹, 菊池崇, 西村幸敏, 松岡彩子, 辻裕司

    第124回 地球電磁気・地球惑星圏学会 総会・講演会     2008.10

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  148. SC研究の最前線

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 亘慎一

    平成20年度・第1回STE(太陽地球環境)現象報告会     2008.9

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  149. あけぼの衛星によって内部磁気圏で観測されるSCに関連した電磁場変動現象

    新堀淳樹, 菊池崇, 小野高幸, 飯島雅英, 熊本篤志, 西村幸敏, 松岡彩子

    第32回極域宙空圏シンポジウム     2008.8

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  150. Penetration of storm-time electric fields to the middle-latitude ionosphere and inner magnetosphere observed by the magnetometers and Akebono satellite Reviewed

    Shinbori, A, Y. Tsuji, T. Kikuchi, A. Matsuoka

    COSPAR     2008.7

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  151. SC related electric and magnetic field phenomena in the inner magnetosphere observed by the Akebono satellite Reviewed

    Shinbori, A, T. Kikuchi, T. Ono, M. Iizima, A. Kumamoto, Y. Nishimura, A. Matsuoka

    Asia Oceania Geosciences Society     2008.6

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  152. 衛星観測に基づく磁気圏内における SC の磁場振幅の日変化

    新堀淳樹, 菊池崇, 辻裕司, 荒木徹, 西村幸敏, 越石英樹, 松本晴久, 五家建夫

    日本地球惑星科学連合2008年大会     2008.5

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  153. 磁気急始 (SC) の振幅の日変化への太陽風 IMF 効果とその季節依存性

    新堀淳樹, 菊池崇, 辻裕司, 荒木徹

    日本地球惑星科学連合2008年大会, 招待講演     2008.5

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  154. 太陽風-磁気圏-電離圏結合過程の基礎理解としての磁気急始(SC)現象の姿

    新堀淳樹, 菊池崇, 辻裕司, 荒木徹

    平成19年度名古屋大学太陽地球環境研究所研究集会 「第3回ジオスペース環境科学研究会」, 招待講演     2008.3

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  155. 太陽風-磁気圏-電離圏結合過程の基礎理解としての磁気急始(SC)現象の姿

    第3回ジオスペース環境科学研究会     2008.3

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  156. SC-associated ionospheric electric fields at low latitude: FM-CW radar observation Reviewed

    Ikeda, A, K. Yumoto, M. Shinohara, K. Nozaki, A. Yoshikawa, A. Shinbori

    Mem. Fac. Sci., Kyushu Univ., Ser. D, Earth and Planet. Sci.,XXXII, 1-6   Vol. 32 ( 1 ) page: 1-6   2008.2

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  157. IMF南点に伴う磁気圏電場の応答とその空間依存性

    西村幸敏, 菊池崇, J. Wygant, 新堀淳樹, 辻裕司, 小野高幸, 飯島雅英, 熊本篤志

    第4回磁気圏-電離圏複合系における対流に関する研究会抄録,50-68     2008

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  158. Transient flow shear in the duskside ionosphere observed by King Salmon HF radar

    堀智昭, 菊池崇, 辻裕司, 新堀淳樹, 大高一弘, 國武学, 亘慎一

    第4回磁気圏-電離圏複合系における対流に関する研究会抄録、72-86     2008

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  159. サブオーロラ帯から磁気赤道域における磁気急始(SC)に伴う磁場変動の日変化の特徴

    新堀淳樹, 辻裕司, 菊池崇, 荒木徹, 亘慎一

    第4回磁気圏―電離圏複合系における対流に関する研究会収録, 133-160     2008

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  160. 磁気嵐急始初期インパルスの数秒以内同時性と地面電離層導波管TM0モード伝播による理解

    菊池崇, 新堀淳樹, 辻裕司, 橋本久美子, 亘慎一, 荒木徹, M. A. Abdu

    第4回磁気圏-電離圏複合系における対流に関する研究会抄録、161-168     2008

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  161. 磁気嵐時の極域磁気圏におけるプラズマ密度増加、イオン上昇流の観測

    北村成寿, 新堀淳樹, 西村幸敏, 小野高幸, 飯島雅英, 熊本篤志, 山田学, 渡部重十, 阿部琢美, A. W. Yau

    第9回惑星圏研究会集録, 17–20     2008

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  162. 磁気嵐時の中緯度領域における地上磁場変動と電離圏電場との定量的関係

    辻裕司, 新堀淳樹, 西村幸敏, 菊池崇, 松岡彩子, 長妻努

    第4回磁気圏-電離圏複合系における対流に関する研究会抄録、87-105     2008

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  163. Seasonal dependence of SC amplitude on magnetic local time Reviewed

    Shinbori, A, T. Kikuchi, T. Araki

    American Geophysical Union Fall Meeting 2007     2007.12

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  164. 地上-衛星観測から見た複合系としての磁気急始(SC)現象の姿-太陽風IMFの極性が与えるSCの振幅の日変化の変動の意味-

    新堀淳樹, 菊池崇, 荒木徹, 辻裕司, 工藤健一, 西村幸敏, 越石英樹, 松本晴久, 五家建夫

    平成19年度名古屋大学太陽地球環境研究所研究集会「第3回磁気圏-電離圏複合系における対流に関する研究会」     2007.11

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  165. 磁気圏・プラズマ圏・地上における磁気急始(SC)の振幅分布と太陽風衝撃波によるオーロラの応答について

    新堀淳樹, 菊池崇, 辻裕司, 工藤健一, 荒木徹, 西村幸敏, 越石英樹, 松本晴久, 五家建夫

    第3回地磁気の会     2007.11

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  166. 磁気急始(SC)の振幅の日変化を用いた電離圏-磁気圏結合の理解-SCの作るFACの季節変動からわかること

    新堀淳樹, 菊池崇, 荒木徹

    平成19年度名古屋大学太陽地球環境研究所研究集会「第3回磁気圏-電離圏複合系における対流に関する研究会」     2007.11

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  167. Statistical view of large-scale electric field in the inner magnetosphere during geomagnetic storms

    Shinbori, A, Y. Nishimura, T. Ono, A. Kumamoto, T. Kikuchi, A. Matsuoka

    International CAWSES Symposium     2007.10

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  168. あけぼの衛星によってプラズマ圏磁気赤道付近で観測される静電的電子サイクロトロン高調波について

    新堀淳樹, 小野高幸, 大家寛

    地球電磁気・地球惑星圏学会 第122回総会及び講演会     2007.9

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  169. SCの振幅の日変化に対する太陽風IMFと季節依存性

    新堀淳樹, 菊池崇, 荒木徹

    地球電磁気・地球惑星圏学会 第122回総会及び講演会     2007.9

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  170. Generation mechanism of Z-mode waves in the equatorial plasmasphere Reviewed

    Y. Nishimura, T. Ono, M. Iizima, A. Shinbori, A. Kumamoto

    Earth, Planets and Space   Vol. 59 ( 9 ) page: 1027-1034   2007.9

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    DOI: 10.1186/BF03352043

  171. 磁気急始(SC)の振幅の磁気地方時とその季節・太陽活動依存性

    新堀淳樹, 菊池崇, 荒木徹

    平成19年度・第1回STE(太陽地球環境)現象報告会     2007.9

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  172. 磁気嵐における電離圏-磁気圏結合研究の時代背景と新展開

    新堀淳樹

    地球電磁気・地球惑星圏関連夏の学校2007     2007.8

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  173. 磁気嵐時の内部磁気圏・極域電離圏電場の統計的描像

    新堀淳樹, 西村幸敏, 小野高幸, 熊本篤志, 菊池 崇

    第31回極域宙空圏シンポジウム     2007.7

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  174. Electrostatic electron cyclotron harmonic waves observed by the Akebono satellite near the equatorial region of the plasmasphere Reviewed

    A. Shinbori, T. Ono, M. Iizima, A. Kumarnot, S. Shirai, A. Hanaoka, K. Okamoto, M. Ohashi, H. Oya

    EARTH PLANETS AND SPACE   Vol. 59 ( 6 ) page: 613-629   2007.6

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    Analysis of the plasma wave observation data provided by the plasma waves and sounder experiment (PWS) on board the Akebono satellite frequently reveals the presence of electrostatic electron cyclotron harmonic (ESCH) waves in the low-latitude region (MLAT &lt; 45 degrees) of the plasmasphere within an altitude range from about 3000 km to the apogee of the satellite (initial apogee was 10,500 km). Even at moderate or low geomagnetic activity, intense ESCH waves often appear near the equatorial region of the plasmasphere above the upper hybrid resonance (UHR) frequency at the lowest harmonic number branch of the f(Qn) ESCH waves. We identified these plasma waves as the equatorial plasmasphere f(Qn) waves (EP-f(Qn)). The spectra of the EP-f(Qn) waves are characterized by a narrow band structure and by a strong nature, with a wave intensity that ranges from 3.46 x 10(-8) to 3.31 X 10(-4) V/m. The maximum intensity is nearly coincident with the upper limit of the PWS receiver in the low-gain mode. Statistical analysis results reveal that the EP-f(Qn) waves are observable in all the local time sectors; however, the occurrence probability shows a clear enhancement in the early morning sector of 01-03 MLT in the plasmasphere. The EP-f(Qn) wave activities are suppressed within a period of strong magnetic disturbances as well as solar minimum phase. The linear dispersion relation analysis using a two-component plasma model reveals that supra-thermal plasma with the energy of about 750 eV and with a large temperature anisotropy (A = T-perp/T-parallel - 1 &gt; 40) must be present in order to realize an appearance of a positive growth rate at the observed frequency and propagation angle of the ESCH waves. Since the hot plasma with such a high anisotropy has not been detected, the validity of the present two-component plasma model remains an open question. The occurrence feature of the ESCH waves showed that there is a constant activation or a constant flow-in of free energy to generate the strong plasma instability of ESCH waves near the post-midnight sector of the plasmasphere. The existence of ESCH waves revealed that the nature of the plasmaspheric plasma is more turbulent and active than has been believed.

    DOI: 10.1186/BF03352723

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  175. Evolution of ring current and radiation belt particles under the influence of storm-time electric fields Reviewed

    Y. Nishimura, A. Shinbori, T. Ono, M. Iizima, A. Kumamoto

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 112 ( A6 )   2007.6

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    Electric field and potential distributions in the inner magnetosphere during geomagnetic storms have been investigated using the Akebono/EFD data. Using this electric field, we study injection of ring current particles and acceleration of radiation belt electrons by single-particle calculations. During the main phase, the dawn-dusk electric field is intensified especially in a range of 2 &lt; L &lt; 5 with a maximum amplitude of 6 mV/m on the duskside, and a two-cell convection pattern with a potential difference of 180 kV is identified. The convection pattern on the equatorial plane is significantly distorted with a large potential drop of 70 kV on the dawn and dusk sectors, indicating an intrinsic source of large-scale electric field in the inner magnetosphere. The plasma sheet ions are gathered into the dusk to premidnight sector in the inner magnetosphere in the region of enhanced electric field due to the strong E x B drift. The ions are transported into around 4 R-E with an acceleration of more than 1 order of magnitude within 40 min, conserving the first adiabatic invariants. Relativistic electrons with initial energy of some hundreds of kiloelectron volts at 5 R-E are energized to more than 100 keV for 3 hours. The energy spectrum during the recovery phase of 9 October 1990 geomagnetic storm observed by the CRRES satellite is reproduced without the radial diffusion or nonadiabatic acceleration by plasma waves. It is possible that this acceleration process is the inhomogeneity of the large-scale electric field, which corresponds to the del x E term along orbits of electrons around the Earth.

    DOI: 10.1029/2006JA012177

    Web of Science

  176. 磁気急始(SC) の振幅の磁気地方時と太陽風IMF の依存性-3

    新堀淳樹, 菊池崇, 荒木徹

    日本惑星科学連合2007年大会     2007.5

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  177. 磁気嵐時における内部磁気圏電場について

    新堀淳樹, 西村幸敏, 小野高幸, 熊本篤志, 菊池崇

    日本地球惑星科学連合2007年大会, 招待講演     2007.5

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  178. 地上-衛星で見た2006年12月14日の磁気嵐における磁場変動

    新堀淳樹, 辻裕司

    平成18年度・第2回STE(太陽地球環境)現象報告会     2007.3

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  179. 磁気嵐と内部磁気圏電場

    新堀淳樹

    第10回学術創成分担者会議・年度末報告会     2007.3

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  180. あけぼの衛星観測による磁気嵐時の極域・中低緯度電離圏電場について

    新堀淳樹, 西村幸敏, 小野高幸, 熊本篤志, 菊池崇

    平成18年度名古屋大学太陽地球環境研究所研究集会 「中緯度短波レーダー研究会」     2007.2

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  181. 磁気嵐の発達・衰退過程におけるサブオーロラ帯・極域電離圏内の電場分布の変化について

    新堀淳樹, 西村幸敏, 菊池崇, 小野高幸, 熊本篤志

    宇宙プラズマ/太陽系環境研究の将来構想座談会5 (SSF5) ~地球磁気圏地上-衛星観測共同研究の深化に向けて~     2007.1

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  182. 複合系物理の基礎課程の理解としての地上-衛生観測から見た磁気急始(SC)現象の姿

    新堀淳樹, 菊池崇, 辻裕司, 工藤健一, 荒木徹, 西村幸敏, 越石英樹, 松本晴久, 五家建夫

    第3回磁気圏―電離圏複合系における対流に関する研究会収録, 85-141     2007

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  183. 磁気嵐における電離圏電場の時間・空間発展

    辻裕司, 新堀淳樹, 菊池崇

    第3回磁気圏―電離圏複合系における対流に関する研究会収録、150-177     2007

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  184. Variations of the electric field distribution in the sub-auroral latitude and polar ionosphere during geomagnetic storms Reviewed

    Shinbori, A, Y. Nishimura, T. Ono, A. Kumamoto, T. Kikuchi

    American Geophysical Union Fall Meeting 2006     2006.12

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  185. 新堀淳樹, 西村幸敏, 菊池崇, 小野高幸, 荒木徹

    新堀淳樹, 西村幸敏, 菊池崇, 小野高幸, 荒木徹

    平成18年度名古屋大学太陽地球環境研究所研究集会 「第2回 磁気圏-電離圏複合系における対流に関する研究会」     2006.11

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  186. 磁気急始(SC)の振幅の磁気地方時と太陽風IMFの依存性-2

    新堀淳樹, 西村幸敏, 菊池崇, 小野高幸, 荒木徹

    地球電磁気・地球惑星圏学会 第120回総会・講演会     2006.11

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  187. Storm-time electric field distribution in the inner magnetosphere Reviewed

    Y. Nishimura, A. Shinbori, T. Ono, M. Iizima, A. Kumamoto

    GEOPHYSICAL RESEARCH LETTERS   Vol. 33 ( 22 )   2006.11

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    The distribution of the storm-time electric field in the inner magnetosphere has been investigated by using the Akebono/EFD data within a period from 1989 to 1995. During the main phase of geomagnetic storms, the strong electric field appears between L = 2 and L = 6 in both dawn and dusk sectors with the magnitude from 2 to 4 mV/m, and the maximum value appears at L = 3 in the dusk sector. During the recovery and weakly disturbed period, the region with intense electric field moves outward with decreasing the amplitude. This structure of the localized electric field is quite different from the Volland-Stern electric field model, suggesting the existence of another electric field source other than the large-scale convection electric field. During quiet periods, although the electric field fairly follows the corotation electric field, the distribution at L = 3.5 indicates a small deviation from pure corotation.

    DOI: 10.1029/2006GL027510

    Web of Science

  188. 磁気嵐時の内部磁気圏電場について

    新堀淳樹, 菊池崇, 西村幸敏, 小野高幸

    第2回ジオスペース環境科学研究会     2006.9

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  189. 磁気嵐時におけるプラズマ圏並びに極域電離圏内の電場分布とその変化

    新堀淳樹, 西村幸敏, 小野高幸, 飯島雅英, 熊本篤志, 菊池 崇

    第30回極域宙空圏シンポジウム     2006.8

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  190. Electric Field and Plasma Dynamics in the Inner Magnetosphere and Plasmasphere during a Geomagnetic Storm Reviewed

    Shinbori, A, Y. Nishimura, T. Ono, M. Iizima, A. Kumamoto

    COSPAR     2006.7

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  191. 内部磁気圏電場の統計的描像-2

    新堀淳樹, 西村幸敏, 小野高幸, 飯島雅英, 熊本篤志

    日本地球惑星科学連合2006年大会, 招待講演     2006.5

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  192. 磁気急始(SC)の磁場変動の振幅に関する未解決問題点

    新堀淳樹, 西村幸敏, 小野高幸, 飯島雅英, 熊本篤志

    第1回地磁気の会     2006.3

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  193. Statistical studies of fast and slow Z-mode plasma waves in and beyond the equatorial plasmasphere based on long-term Akebono observations Reviewed

    Y. Nishimura, T. Ono, M. Iizima, A. Shinbori, A. Kumamoto, H. Oya

    Earth, Planets and Space   Vol. 58 ( 3 ) page: 343-346   2006.3

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    DOI: 10.1186/BF03351930

  194. Enhancements of magnetospheric convection electric field in the inner magnetosphere associated with sudden commencements Reviewed

    Shinbori, A, T. Ono, M. Iizima, A. Kumamoto

    Advances in Space Research, Volume 38, Issue 8, 1595-1607, doi: 10.1016/j.asr.2005.05.082     2006.1

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    DOI: 10.1016/j.asr.2005.05.082

  195. 磁気急始(SC)の振幅の磁気地方時と太陽風IMF依存性

    新堀淳樹, 西村幸敏, 小野高幸, 菊池崇, 荒木徹

    第2回磁気圏―電離圏複合系における対流に関する研究会収録, 35-74     2006

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  196. 磁気嵐時の内部磁気圏電場と沿磁力線電流

    西村幸敏, 新堀淳樹, 小野高幸, 飯島雅英, 熊本篤志

    第2回磁気圏―電離圏複合系における対流に関する研究会収録、75-84     2006

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  197. あけぼの衛星で見る磁気急始(SC)並びに磁気嵐に伴う内部磁気圏電場構造の時空間変動

    新堀淳樹, 西村幸敏, 小野高幸, 飯島雅英, 熊本篤志, 大家寛

    平成18年度名古屋大学太陽地球環境研究所研究集会「第1回磁気圏-電離圏複合系における対流に関する研究会」     2005.11

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  198. 内部磁気圏電場の統計的描像

    新堀 淳樹, 西村 幸敏, 小野 高幸, 飯島 雅英, 熊本 篤志

    地球電磁気・地球惑星圏学会 第118回総会・講演会     2005.10

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  199. 磁気嵐時におけるオーロラキロメートル放射(AKR)と地球ヘクトメートル放射(THR)の活動について

    新堀 淳樹, 西村 幸敏, 小野 高幸, 飯島 雅英, 熊本 篤志, 佐藤 由佳

    地球電磁気・地球惑星圏学会 第118回総会・講演会     2005.9

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  200. 磁気嵐中に観測される内部磁気圏・プラズマ圏内の電場変動について

    新堀 淳樹, 小野 高幸, 飯島 雅英, 熊本 篤志, 大家 寛

    地球惑星圏関連学会2005年合同大会     2005.5

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  201. 磁気急始(SC)の振幅の磁気地方時と太陽風IMFの依存性

    新堀 淳樹, 小野 高幸, 飯島 雅英, 熊本 篤志, 西村 幸敏

    地球惑星圏関連学会2005年合同大会     2005.5

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  202. Convection electric fields in the inner magnetosphere caused by sudden commencements

    Shinbori, A, T. Ono, M. Iizima, A. Kumamoto

    Joint International Workshop on Space Weather: On the causes of southward IMF and space weather, science and application for Japanese CAWSES, Tokyo     2005.4

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  203. Electrodynamics in the duskside inner magnetosphere and plasmasphere during a super magnetic storm on March 13-15, 1989 Reviewed

    A Shinbori, Y Nishimura, T Ono, M Iizima, A Kumamoto, H Oya

    EARTH PLANETS AND SPACE   Vol. 57 ( 7 ) page: 643-659   2005

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    Variations of cold plasma density distribution and large-scale electric field in the inner magnetosphere and plasmasphere during a geomagnetic storm were investigated by using the observation data of the Akebono satellite which has been carried out for more than 15 yeas since March, 1989. We focus on the super geomagnetic storm on March 13-15, 1989, for which the maximum negative excursion of the Dst index was -589 nT. During the main phase of the magnetic storm, the strong convection electric field with a spatially inhomogeneous structure appears in the inner magnetosphere between L = 2.0 and 7.0. The averaged intensity of the electric field was in a range of about 2.5-9.2 mV/m. The spatial distribution in the magnetic equatorial region indicates that the magnitude within an L-value range of 2.2-7.0 is much larger than that observed at L = 7.0-10.0. Associated with the appearance of the strong convection electric field, the cold plasma density near the trough region around L = 3.0-6.0 was enhanced with one or two order magnitude, compared with that in the magnetically quiet condition. This implies that a mount of the ionospheric plasma may be supplied from the topside ionosphere into the trough and plasmasphere regions by the frictional heating due to the fast plasma convection in the ionosphere as pointed out by previous studies on the enhancements of plasma density in these regions, based on incoherent scatter radar and total electron content (TEC) observations (e.g., Yeh and Foster, 1990; Foster et al., 2004). During the recovery phase of the magnetic storm, the convection electric field observed in the inner magnetosphere and plasmasphere regions recovers within 3-4 days almost up to the level of the magnetically quiet condition.

    DOI: 10.1186/BF03351843

    Web of Science

  204. あけぼの衛星で見る磁気急始(SC)・磁気嵐に伴う内部磁気圏電場構造の時空間変動とプラズマ圏ダイナミクス

    新堀淳樹, 小野高幸, 飯島雅英, 熊本篤志, 大家寛

    第1回磁気圏―電離圏複合系における対流に関する研究会収録, 58-84     2005

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  205. 地磁気擾乱時における放射線帯電子のピッチ角分布の変動

    西村 幸敏, 新堀 淳樹, 小野 高幸, 飯島 雅英, 熊本 篤志, 森岡 昭

    第5回惑星電磁圏・大気圏研究会集録     2005

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  206. プラズマ圏磁気赤道域UHR、Z-mode波動の統計的描像

    西村幸敏, 小野高幸, 飯島雅英, 熊本篤志, 新堀淳樹, 大家寛

    第9回SGEPSS生存圏波動分科会研究収録、WAVE09-02     2005

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  207. 磁気嵐時の背景電場による放射線、環電流粒子生成

    西村幸敏, 新堀淳樹, 小野高幸, 飯島雅英, 熊本篤志

    第1回磁気圏―電離圏複合系における対流に関する研究会収録, 29-34     2005

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  208. SC・磁気嵐中における内部磁気圏・プラズマ圏の電場応答とプラズマ密度変動

    新堀 淳樹, 小野 高幸

    平成16年度 名古屋大学太陽地球環境研究所研究集会 「中緯度短波レーダー研究会」     2004.10

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  209. 磁気嵐中に内部磁気圏・プラズマ圏で観測される電場について

    新堀 淳樹, 小野 高幸, 飯島 雅英, 熊本 篤志, 大家 寛

    プラズマ圏・内部磁気圏研究集会     2004.8

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  210. SC related plasma waves observed by the Akebono satellite in the polar region and inside the plasmasphere region

    Shinbori, A, T. Ono, M. Iizima, A. Kumamoto, H. Oya

    International Review Meeting on the Northern Environmental Change Research Project   Vol. 108 ( A12 )   2004.3

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    Plasma wave phenomena associated with sudden commencements (SC) are analyzed using the database of the Akebono satellite observations that have been carried out for more than 13 years since March 1989. All the 719 data sets simultaneously observed in the periods of SC events show that plasma waves are enhanced with one-to-one correspondence to SCs in entire regions of the polar cap, auroral zone, and plasmasphere within a response time of +/-90 s. In the middle latitude and equatorial regions of the plasmasphere, intensification and frequency shift of electromagnetic whistler mode, LHR waves, and ion cyclotron harmonic waves are found. The electric field variations in this region also show clear response to the onset of SCs with the amplitude of 0.2-30 mV/m. The variations are observed in the nightside as well as dayside sectors, and no clear dependence of magnetic latitude, local time, and L shell is found. On the other hand, electrostatic whistler mode waves and electromagnetic ion cyclotron waves which show broadband spectra are generated in the high-latitude region. Spectra of low-energy particles observed simultaneously with the enhancement of these plasma waves show that electron fluxes are enhanced in all of pitch angle bins of the low-energy particle detector onboard the Akebono satellite. Near the cusp region, the ion fluxes are more enhanced in the upward direction than in the downward direction along the magnetic field lines. In about half of the cases of the high-latitude events, sudden appearance and intensification of AKR are also found after the onsets of SC. The delay time between the onsets of SC and AKR enhancement shows several minutes with the average time of 5.7 min. Time differences between the onsets of SC measured at Kakioka Magnetic Observatory and plasma wave enhancements observed by the Akebono satellite show positive correlation with possible delay time according to the propagation route of SC disturbances. Propagation character of SC disturbances shows two group signatures: one group takes a route which crosses the geomagnetic equator region with an average speed of 389.5 km/s. The speed is almost consistent with plasmaspheric fast-mode MHD wave velocity. The other group takes a route which starts from the dayside cusp region. In the second case, the SC disturbances propagate through the polar ionosphere region from the dayside to the nightside sectors with an average speed of 47 km/ s in the X-GSM coordinate corresponding to the ionospheric fast-mode MHD wave velocity.

    DOI: 10.1029/2003JA009964

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  211. SC related electric and magnetic field phenomena observed by the Akebono satellite inside the plasmasphere Reviewed

    A Shinbori, T Ono, M Iizima, A Kumamoto

    EARTH PLANETS AND SPACE   Vol. 56 ( 2 ) page: 269 - 282   2004

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    Electric and magnetic field variations inside the plasmasphere associated with SCs identified on the ground are analyzed based on the Akebono satellite observations which have been carried out more than 13 years since March 1989. 126 electric field observation data corresponding to SCs show abrupt change of intensity as well as direction within a few minutes inside the plasmasphere. Temporal variations of the electric field showed a bipolar waveform with the amplitude range of 0.2-38 mV/m. The electric field signature is followed by a dumping oscillation with the period of Pc3-4 ranges. The magnetic field variations of 33 SCs also show an abrupt increase of 0.2-65 nT within a few minutes, which indicate the compression of the magnetosphere due to the discontinuity of solar wind. The initial excursion of the electric field during SCs tends to be directed westward. The amplitude does not show a dependence on magnetic local time that has been observed outside the plasmasphere. The magnitude of the electric field variations tends to be proportional with the power of 0.6 to the magnetic field variation in the plasmasphere. The Poynting vector of the initial SC impulse is directed toward the earth, which suggests that energy of magnetic disturbances associated with SCs propagates toward the earth inside the plasmasphere with the refraction due to the plasma density gradient. One of the most interesting results from the present study is that a DC offset of the Ey component of the electric field appears after the initial electric field impulse associated with SCs. This signature is interpreted to be a magnetospheric convection electric field penetration into the inner plasmasphere (L=2.5). The intensity of the offset of the Ey field gradually increases by 0.5-2.0 mV/m about 1-2 minutes after the onset of the initial electric field impulse and persists about 10-30 minutes.

    DOI: 10.1186/BF03353409

    Web of Science

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  212. SC・磁気嵐中に内部磁気圏・プラズマ圏内で観測される電場変動について

    新堀淳樹, 小野高幸, 飯島雅英, 熊本篤志, 大家寛

    第4回CAWSES電磁圏シンポジウム研究会収録、9-12     2004

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  213. あけぼの衛星によって観測されるプラズマ圏磁気赤道域付近の静電的電子サイクロトロン高調波の出現特性について

    新堀淳樹, 小野高幸, 飯島雅英, 熊本篤志, 大家寛

    第8回SGEPSS波動分科会研究会収録, WAVE08-02     2004

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  214. プラズマ圏磁気赤道域Z-mode波の放射機構 - keV電子による直接励起の可能性

    西村幸敏, 小野高幸, 飯島雅英, 新堀淳樹, 熊本篤志, 大家寛

    第4回惑星電磁圏・大気圏研究会集録,103-107     2004

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  215. SCに伴うプラズマ圏内のプラズマ波動、場の変動特性について

    新堀 淳樹, 小野 高幸, 飯島 雅英, 熊本 篤志, 大家 寛

    地球電磁気・地球惑星圏学会 第114回総会・講演会     2003.11

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  216. SC-related kilometric and hectometric radiations observed by the Akebono satellite in the polar regions Reviewed

    Shinbori, A, T. Ono, M. Izima, K. Kumamoto, H. Oya

    Advances in polar upper atmosphere research   Vol. 17   page: 60-76   2003.9

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  217. 磁気急始(SC)に伴うプラズマ波動、場の変動現象について

    新堀 淳樹, 小野 高幸

    プラズマ圏・内部磁気圏研究集会     2003.8

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  218. SC triggered plasma wave and field phenomena observed by the Akebono satellite in the plasmasphere

    Shinbori, A, T. Ono, M. Iizima, A. Kumamoto, H. Oya

    International Union of Geodesy and Geophysics     2003.7

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  219. SC triggered plasma wave and field phenomena observed by the Akebono satellite in the plasmasphere

    Shinbori, A, T. Ono, M. Iizima, A. Kumamoto, H. Oya

    International Union of Geodesy and Geophysics     2003.7

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  220. SC・磁気嵐に伴うプラズマ圏内のプラズマ波動、場の変動現象について

    新堀 淳樹, 小野 高幸

    内部磁気圏分科会     2003.5

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  221. SC-triggered plasma waves observed by the Akebono satellite in the polar regions and the plasmasphere Reviewed

    Shinbori, A, T. Ono, H. Oya

    Advances in polar upper atmosphere research   Vol. 16   page: 126-135   2002.9

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  222. SCに伴うプラズマ圏内の諸現象と擾乱の伝播

    新堀 淳樹, 小野 高幸, 大家 寛

    プラズマ圏・内部磁気圏研究会     2002.8

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  223. SCに伴うAKRの発生について

    新堀 淳樹, 小野 高幸, 大家 寛

    第26回極域における電離圏磁気圏総合観測シンポジウム     2002.7

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  224. SC triggered disturbances in the magnetosphere and plasmasphere

    Shinbori, A, T. Ono, H. Oya

    Western Pacific Geophysics Meeting 2002     2002.7

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  225. SCに伴う磁気圏内擾乱域の発生と伝播について

    新堀 淳樹, 小野 高幸, 大家 寛

    地球惑星圏関連学会2002年合同大会     2002.5

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Research Project for Joint Research, Competitive Funding, etc. 8

  1. 研究データの可視化・検索向上を目指したメタデータマネジメントの実践

    2023.7 - 2024.3

    2023年度公募型共同研究「ROIS-DS-JOINT」 

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\816000 ( Direct Cost: \816000 )

  2. 磁気嵐時におけるグローバルなプラズマ圏・プラズマ圏界面の 時間・空間変動特性

    2017.4 - 2020.3

    一般共同研究 

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\284000 ( Direct Cost: \284000 )

  3. 極域-中緯度における地磁気静穏日変化と中性風の長期変動に関する研究

    2015.4 - 2017.3

    一般共同研究 

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\294000 ( Direct Cost: \294000 )

  4. 極域-中緯度における地磁気静穏日変化と中性風の長期変動に関する研究

    2014.4 - 2015.3

    地上ネットワーク観測大型共同研究 

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    Grant type:Competitive

    Grant amount:\254000 ( Direct Cost: \254000 )

  5. 磁気観測および中間圏・下部熱圏における風速観測データに見られる 長期変動の解析

    2013.4 - 2014.3

    地上ネットワーク観測大型共同研究 

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\433000 ( Direct Cost: \433000 )

  6. 磁気嵐時におけるグローバル地磁気変動と電離圏擾乱ダイナモに関する研究

    2010.11 - 2011.3

    京都大学若手研究者スタートアップ研究費 

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    Grant type:Competitive

    Grant amount:\680000 ( Direct Cost: \680000 )

  7. あけぼの衛星によって観測された磁気急始(SC)に伴う内部磁気圏における対流電場の増強の特徴

    2010.7

    国際学会出席旅費支援 

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    Authorship:Principal investigator  Grant type:Competitive

  8. Response of convection electric field in the inner magnetosphere plasmasphere region during a major magnetic storm

    2005.7

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KAKENHI (Grants-in-Aid for Scientific Research) 10

  1. 地上―衛星観測と物理モデルを組み合わせた磁気嵐時の電離圏ー熱圏結合過程の解明

    2024.4

    科学研究費補助金   基盤研究(C)

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    Authorship:Principal investigator  Grant type:Competitive

    Direct Cost: \3600000 )

  2. 地磁気擾乱時における電離圏電場分布の変動と電離圏擾乱ダイナモとの関係

    Grant number:26400478   2014.4 - 2019.3

    科学研究費補助金  基盤研究(C)

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    Authorship:Principal investigator  Grant type:Competitive

    Direct Cost: \3700000 )

  3. 自然電磁波の広帯域サウンディングによる未踏の中間圏電子密度4次元探査

    2024.4

    科学研究費補助金 

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    Authorship:Coinvestigator(s)  Grant type:Competitive

  4. Development of a high spatial-temporal resolution geospace observation network using the mid-latitude SuperDARN

    Grant number:22H01284  2022.4 - 2027.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

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  5. Study of global-scale ionospheric electric field dynamics using mid-latitude SuperDARN under common research infrastructure

    Grant number:18KK0099  2018.10 - 2024.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))

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  6. Temporal and spatial variations of ionospheric electric fields during geomagnetic storms and the relation to ionospheric disturbance dynamo

    Grant number:26400478  2014.4 - 2019.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Shinbori Atsuki

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    Grant amount:\4810000 ( Direct Cost: \3700000 、 Indirect Cost:\1110000 )

    Geomagnetic storms caused by solar wind disturbances related to a solar surface phenomenon (solar flare) and a sudden change in the solar wind structure lead to a severe change in the electromagnetic and plasma environment in a wide region from the magnetosphere to ionosphere. In this study, we analyzed solar wind, geomagnetic field and global total electron content (TEC) data to clarify the temporal and spatial variations of ionospheric electric fields and electron density associated with geomagnetic storms. As a result, a two-cell ionospheric convection is enhanced significantly in the polar regions and the polar electric field penetrates to the equatorial ionosphere during the main phase of the geomagnetic storms. Associated with the instantaneous distribution of storm-time electric field, the electron density enhancement begins in the midlatitude ionosphere and propagates to the low-latitude ionosphere as the geomagnetic storms develop.

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  7. Storm-time global geomagnetic field variation and ionospheric disturbance dynamo

    Grant number:23740369  2011 - 2014

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (B)

    SHINBORI Atsuki

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    Grant amount:\4030000 ( Direct Cost: \3100000 、 Indirect Cost:\930000 )

    In the present study, we analyzed geomagnetic field data obtained from geomagnetic observatories distributed from both the poles and equator together with solar wind data in order to investigate the characteristics of global geomagnetic field and thermospheric wind variations during geomagnetic storms. As a result, during the main phase of geomagnetic storm caused by southward turning of the interplanetary magnetic field (IMF), the region-1 type of ionospheric currents were developed from the polar to middle-latitude regions and the eastward equatorial electrojet (EEJ) current on the dayside was intensified due to penetration of the polar ionospheric electric field to the equator. On the other hand, during the recovery phase of geomagnetic field caused by northward turning of the IMF, the region-2 type of ionospheric currents appeared in the middle-latitude regions. Moreover, the westward EEJ current driven by the region-2 electric field was developed on the dayside during this period.

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  8. Study of atmospheric waves in the mesosphere-lower thermosphere (MLT) region with a radar network

    Grant number:22253006  2010.4 - 2016.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

    Tsuda Toshitaka, HAYASHI Hiroo, HASHIGUCHI Noriko, SHINBORI Atsuki, HAYASHI Hiroo, HASHIGUCHI Noriko, SHINBORI Atsuki

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    We studied the behavior of atmospheric waves as well as long-term variations of the monthly mean winds in the Mesosphere-Lower Thermosphere (MLT) region at 60-150 km altitude, focusing on the coupling processes between different atmospheric layers due to upward propagating waves. We utilized archived data-sets (IUGONET) collected by a number of meteor and medium frequency (MF) radars operated continuously for many years since 1990’s at low latitudes in Asia and Pacific regions. We investigated seasonal variations of the atmospheric gravity activity in the tropics, and found its relation with cloud convection in the lower atmosphere. Monthly mean zonal and meridional winds exhibited peculiar variations with semi-annual (SAO), annual, quasi-biennial (QBO), and intra-seasonal periods. Our analysis suggested importance of interaction of atmospheric waves with the mean flow to drive these regular and irregular variations. The mean meridional winds showed a trend with a decadal time scale.

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  9. 磁気嵐に伴う磁気圏・電離圏内におけるプラズマ擾乱の発生と発達過程の研究

    Grant number:06J06408  2006 - 2008

    日本学術振興会  科学研究費助成事業  特別研究員奨励費

    新堀 淳樹

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    太陽フレア現象によって放出される高密度・高温プラズマ雲が地球磁気圏に衝突することによって発生する磁気急始(SC)現象は、開始時刻やその発生要因が見極めやすい変動形態を持つため、太陽風-磁気圏-電離圏相互作用という磁気圏物理の基礎課程を理解する上で非常に重要な擾乱現象である。本年度は、磁気赤道から中緯度領域におけるSCの磁場振幅の磁気緯度と磁気地方時の分布を明らかするために、ヤップ、グアム、沖縄、柿岡、女満別そしてパラツンカの6つの地磁気観測点から得られた長期の地磁気データを用いてSCのMain Impulse(MI)期の磁場振幅の統計解析を行った。その結果、昼間側の中緯度における磁場変動は、圧縮時によって生成される領域1型の沿磁力線電流(FAC)のもたらすtwo-cell型の電離圏Hall電流の作る磁場変化を示し、その影響が少なくとも沖縄付近の低緯度まで広がっていた。一方、低緯度では、磁場振幅が正午付近で最大となる磁気圏界面電流のつくる磁場変動が卓越することを示したが、本研究の精密な解析により、極域起源の電離圏電流の作る磁場変動が約7%含まれることを新たに見出した。さらに、磁気赤道の8時から16時の昼間側において、Cowling効果による顕著なSCの磁場振幅の増大が見受けられ、低緯度の2-3倍に達していた。その最大値を与える磁気地方時は11時付近であった。そして、もう一つの興味深い結果は、磁気赤道から中緯度の全ての領域で真夜中付近を最大とする2次的なSCの磁場振幅の増大が見られたことである。その真夜中付近の振幅は。顕著な磁気緯度の依存性を持っており、磁気緯度の増加とともに振幅が増加するという傾向を示した。このことから、この磁場変動をもたらす原因は、MI期に形成されるFACの作る磁場変化であり、その影響が中緯度や低緯度だけでなく、磁気赤道にまで及んでいることをはじめて示した。

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  10. 磁気急始(SC)による磁気圏内プラズマ擾乱の発達過程の研究

    Grant number:04J03113  2005 - 2006

    日本学術振興会  科学研究費助成事業  特別研究員奨励費

    新堀 淳樹

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    磁気急始(SC)やそれに続く磁気嵐に伴って引き起こされる内部磁気圏・プラズマ圏内の電流、電場や磁気擾乱の発生並びに発達過程でのプラズマの応答、擾乱の伝播、エネルギーや物質の輸送機構ついては、現在、未発達の分野として残されている。本研究では、内部磁気圏・プラズマ圏におけるSC、その後の磁気嵐の発達過程に呼応した擾乱の発生、エネルギーの伝達や物質の輸送機構について解明することを目的としている。本年度は1989年3月から2003年12月に至るまでの約15年間という長期間のあけぼの衛星の電場並びにプラズマ波動観測データを用いて、磁気嵐における内部磁気圏電場の形成過程とプラズマダイナミクスの解明に向けた解析を行った。その結果、各磁気嵐の主相時においてこれまで存在していなかった空間的に不均質な大電場がL=2.0-7.0の地球近傍の朝側領域と夕方側の内部磁気圏内に形成されていることが判明し、その最大強度は、数10mV/mにまで達していた。また、この電場の最大強度は、磁気嵐の規模に呼応して強くなる傾向を示し、その最大強度をとる位置も地球側へ接近してくるという様相が明らかとなった。特に、この不均質な大電場が主に動径方向を向いているという特徴に本研究では着目し、夜側のプラズマシートから内部磁気圏に注入された環電流粒子の局所的な電荷分離によって形成されるという新たな内部磁気圏電場モデルを提案した。一方、プラズマ圏のプラズマ密度構造と磁気嵐時の電場構造との比較を行った結果、プラズマ密度が局所的に周囲よりも減少している領域にほぼ対応して背景電場が局所的に増加していることが見出され、この局所電場がプラズマ圏構造とダイナミクスに重要な役割を演じていることが明らかとなった。

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Social Contribution 1

  1. 宇宙天気について

    Role(s):Lecturer

    名古屋大学宇宙地球環境研究所  岡崎高等学校 体験学習  2023.6

Media Coverage 50

  1. Look! Excessive Tonga volcano eruption leaves a telltale finger-print in area Internet

    The Media Lord  2022.8

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  2. An extreme volcanic eruption in Tonga creates a visible fingerprint in space Internet

    Bolly Inside  Sports News  2022.8

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  3. Look! Tonga’s large volcanic eruption leaves a transparent fingerprint on the panorama Internet

    Elondonbuzz  Science  2022.8

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  4. Looks! The eruption of the extreme Tonga volcano leaves a telltale fingerprint in space Internet

    Breaking News  Science  2022.8

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  5. Look at! Extreme eruption of Tonga volcano leaves telltale fingerprint in space Internet

    The Golden News  2022.8

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  6. LOOK! EXTREME TONGA VOLCANO ERUPTION LEAVES A TELLTALE FINGER-PRINT IN SPACE Internet

    INVERSE  2022.8

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  7. Massive underwater eruption may help predict tsunamis, scientists say Internet

    AM Costa Rica  2022.7

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  8. Shockwave caused by Tonga underwater eruption may help scientists predict future tsunami Internet

    AlphaGalileo  2022.7

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  9. Tonga Volcanic Eruption May Help Predict Future Tsunami, Study Suggests Internet

    Insurance Bix  2022.7

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  10. Así ayudará el volcán de Tonga a predecir tsunamis Internet

    Faro de Vigo  2022.7

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  11. Así ayudará el volcán de Tonga a predecir tsunamis Internet

    Información  2022.7

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  12. トンガ噴火時も発生「電離層の乱れ」 津波早期検知に期待 名大チーム確認 Newspaper, magazine

    毎日新聞  2022.7

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  13. Así ayudará el volcán de Tonga a predecir tsunamis Internet

    SPORT  2022.7

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  14. Así ayudará el volcán de Tonga a predecir tsunamis Internet

    Elperiodico  2022.7

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  15. Tonga Volcanic Eruption May Help Predict Future Tsunami, Study Suggests

    Hindiblogger Tech  2022.7

  16. New detection method could give hours of extra warning of a tsunami, save countless lives – ScienceDaily Internet

    getaboutcolumbia.com  Science  2022.7

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  17. トンガ海底火山噴火による電離圏擾乱が高速で伝わるメカニズムを解明 名大ら Internet

    NEWS SALT  2022.7

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    名古屋大学は14日、2022年1月に発生した南太平洋トンガ諸島のフンガ・トンガ-フンガ・ハアパイ火山の大規模噴火に伴って生じた気圧波と同期した同心円上の電離圏擾乱じょうらんが地球規模で広がっていく様相を、全球測位衛星システム(GNSS)などのデータを解析して、捉えることに成功したと発表した。

    日本で電離圏擾乱が観測されたタイミングは、音速に近い気圧波が到来する約3時間前だった。これは、オーストラリアから日本に地球の磁力線沿いに1000km/sの速さで電離圏の擾乱が伝わったことを示している。この研究成果は地球科学の総合国際学術雑誌「Earth, Planets and Space」に13日付で掲載された。

    地球大気圏の高度80Km以上の上部には太陽放射によって電離層が形成されていて、全球測位衛星システム(GNSS) 、衛星放送・通信で使われている電波はこの領域を必ず通過する。電離層が激しく乱れる擾乱が発生するとGNSSの位置情報に誤差が生まれることがあり、これを逆手に取ってGNSS受信機網データを活用した電離圏擾乱の研究が進められている。

    電離層は太陽活動による影響を受けるだけでなく、地震、火山噴火、津波、台風などの気象現象といった下層大気で発生した大気擾乱の影響も受ける。これは地震で発生した津波が下層大気を揺さぶることによって大気振動(音波)や大気波動が生成され、それらが上空の電離圏に伝わることで、電離圏電子密度擾乱を引き起こすと考えられている。

    名古屋大学宇宙地球環境研究所 新堀淳樹特任助教らの研究グループは、情報通信研究機構、電気通信大学との共同研究により、世界各地に設置されている約9000台に及ぶGNSS受信機データを解析して全電子数(TEC:電子の柱状数密度)をデータベース化した。また、気象衛星ひまわり8号の赤外輝度温度データと北海道陸別町に設置された電離圏観測用レーダー(SuperDARNレーダー)のデータも使用した。

  18. SCIENCE Shockwave Caused By Tonga Underwater Eruption May Help Scientists Predict Future Tsunamis Internet

    TECHNO BLENDER  2022.7

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  19. Shockwave caused by Tonga underwater eruption may help scientists predict future tsunami Internet

    ScienceDaily  2022.7

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  20. ONDA DE CHOQUE CAUSADA PELA ERUPÇÃO SUBMARINA DE TONGA PODE AJUDAR OS CIENTISTAS A PREVER FUTUROS TSUNAMIS Internet

    TERRA RARA  2022.7

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  21. Tonga Volcanic Eruption May Help Predict Future Tsunami, Study Suggests Internet

    AKASHSHREE TECH  Science  2022.7

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  22. Wulkan Tonga wywołał olbrzymią falę! Badacze skorzystali na tym i pokazali, jak przewidywać tsunami

    chip  Tech  2022.7

  23. The Tonga Volcanic Eruption Might Be a Help in Predicting Your Future Tsunami, According to a Study Internet

    techmarmot  2022.7

  24. Schnellere Tsunami-Warnungen aufgrund von GPS-Störungen Internet

    ICT  2022.7

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  25. Schnellere Tsunami-Warnungen

    Pressetext  HIGHTECH  2022.7

  26. Studiare la ionosfera per prevedere gli tsunami Internet

    Global Science  2022.7

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  27. Tsunami Prediction Could Become Possible Using Data From Tonga Underwater Volcano Eruption Internet

    The Science Times  ENVIRONMENT & CLIMATE  2022.7

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  28. A study suggests that the eruption of the Tonga Volcanic Eruption might help predict the future tsunami Internet

    list23  TECH  2022.7

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  29. NEW DETECTION METHOD COULD GIVE HOURS’ EXTRA WARNING OF A TSUNAMI, SAVING COUNTLESS LIVES — SCIENCEDAILY Internet

    Air Quality Index  2022.7

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  30. Tonga Volcanic Eruption Might Assist Predict Future Tsunami, Research Suggests Internet

    Frp Bypass Free  2022.7

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  31. Information from the Tonga eruption might assist predict future tsunamis Internet

    AllMaa  2022.7

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  32. Shockwave Caused By Tonga Underwater Eruption May Help Scientists Predict Future Tsunamis Internet

    My Droll  2022.7

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  33. Knowledge From Tonga Volcanic Eruption Could Support Us Brace for Upcoming Tsunami Internet

    Breaking Tech News  Technology  2022.7

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  34. Data From Tonga Volcanic Eruption May Help Us Brace for Future Tsunami Internet

    Mondaydaily  2022.7

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  35. Information From Tonga Volcanic Eruption Might Assist Us Brace for Future Tsunami Internet

    Dailynewz  Tech  2022.7

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  36. Tonga Volcanic Eruptions Could Help Predict Future Tsunamis, Research Proposal Internet

    News7h  Tech  2022.7

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  37. Knowledge From Tonga Volcanic Eruption Could Assist Us Brace for Future Tsunami Internet

    Dirrectly  Technology  2022.7

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  38. Die durch den Tonga-Unterwasserausbruch verursachte Schockwelle könnte Wissenschaftlern helfen, zukünftige Tsunamis vorherzusagen Internet

    GAMINGSYM GERMANY  2022.7

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  39. Information From Tonga Volcanic Eruption Could Assist Us Brace for Future Tsunami Internet

    Growdemy  2022.7

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  40. Tonga Volcanic Eruption Could Assist Predict Future Tsunami, Examine Suggests Internet

    The perfectech  Mobile  2022.7

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  41. Data From Tonga Volcano Eruption May Help Us Cope With Future Tsunamis Internet

    Nitbuz  2022.7

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  42. La onda de choque causada por la erupción submarina de Tonga puede ayudar a los científicos a predecir futuros tsunamis Internet

    Notiulti  2022.7

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  43. Tonga : l’onde de choc d’une éruption sous-marine pourrait aider à prédire un futur tsunami Internet

    Generationsnouvelles  2022.7

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  44. Tonga Volcanic Eruption May Help Predict Future Tsunami, Study Suggests Internet

    Tech  Science  2022.7

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  45. Data From Tonga Volcanic Eruption May Help Us Brace for Future Tsunami Internet

    Daily Hindustan News  Technology  2022.7

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  46. Tonga Volcanic Eruption May Help Predict Future Tsunami, Study Suggests Internet

    REALTIME INDIA  TECHNOLOGY  2022.7

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  47. Shockwave from Tonga eruption may help predict tsunamis Internet

    earth.com  2022.7

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  48. 上空の電子乱れで津波を早く検知可能 トンガ噴火解析 名古屋大 Newspaper, magazine

    毎日新聞  2022.7

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  49. Scientists may be Able to Anticipate Future Tsunamis Thanks to the Tonga Underwater Eruption’s Shockwave Internet

    ASSIGNMENT POINT  ENVIRONMENT  2022.7

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  50. Tonga Volcanic Eruption May Help Predict Future Tsunami, Study Suggests Internet

    gadgets360  Science News  2022.7

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