Faculty Profiles - SHINBORI Atsuki

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

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

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

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Fuji Technology Press Ltd.

<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>

DOI： 10.20965/jdr.2018.p0535

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

CiNii Research

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

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

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

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

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.

DOI： 10.1186/s40623-017-0745-9

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

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

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

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.

DOI： 10.1002/2017JA023990

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

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

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

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

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

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

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.

DOI： 10.1016/j.jastp.2016.01.013

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

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

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.

DOI： 10.1186/s40623-016-0444-y

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

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

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

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

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

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

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

Language：English Publishing type：Research paper (scientific journal) Publisher：COPERNICUS GESELLSCHAFT MBH

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.

DOI： 10.5194/angeo-34-369-2016