Researcher Database

Junichi Kurihara
Faculty of Science
Specially Appointed Associate Professor

Researcher Profile and Settings

Affiliation

  • Faculty of Science

Job Title

  • Specially Appointed Associate Professor

Degree

  • Ph.D.(The University of Tokyo)

J-Global ID

Research Interests

  • Ionosphere   Thermosphere   Remote sensing   Micro-satellite   

Research Areas

  • Environmental science/Agricultural science / Agricultural environmental and information engineering
  • Aerospace, marine, and maritime Engineering / Aerospace engineering
  • Natural sciences / Space and planetary science

Academic & Professional Experience

  • 2013/10 - Today Hokkaido University Faculty of Science
  • 2011/04 - 2013/09 Hokkaido University Faculty of Science
  • 2010/01 - 2011/03 Hokkaido University Faculty of Science
  • 2007/04 - 2009/12 Nagoya University Solar-Terrestrial Environment Laboratory
  • 2004/04 - 2007/03 Japan Aerospace Exploration Agency

Education

  •        - 2004/03  The University of Tokyo  Graduate School of Science  Department of Earth and Planetary Science
  •        - 1998/03  The University of Tokyo  Department of Earth and Planetary Physics

Association Memberships

  • THE REMOTE SENSING SOCIETY OF JAPAN   American Geophysical Union   SOCIETY OF GEOMAGNETISM AND EARTH, PLANETARY AND SPACE SCIENCES   

Research Activities

Published Papers

  • Junichi KURIHARA, Toshinori KUWAHARA, Shinya FUJITA, Yuji SATO, Kosuke HANYU, Morokot SAKAL, Yu MURATA, Hannah TOMIO, Yukihiro TAKAHASHI, Wing-Huen IP
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN 18 (5) 186 - 191 2020/09 [Refereed][Not invited]
  • Junichi Kurihara, Tetsuro Ishida, Yukihiro Takahashi
    Unmanned Aerial Vehicle: Applications in Agriculture and Environment 25 - 38 2020 [Not refereed][Not invited]
  • Nagatsuma, T, A. Kumamoto, M. Ozaki, K. Kitamura, Y. Saito, T. Takashima, M. Nose, J. Kurihara, H. Kojima, K. Ishisaka, A. Matsuoka, R. Nomura, T. Ishida, Y. Takahashi
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN 16 687 - 690 2018/11 [Refereed][Not invited]
  • HPT: A High Spatial Resolution Multispectral Sensor for Microsatellite Remote Sensing
    Kurihara Junichi, Takahashi Yukihiro, Sakamoto Yuji, KUWAHARA Toshinori, Kazuya Yoshida
    Sensors 619 (18) 1 - 11 2018/02 [Refereed][Not invited]
  • Tetsuro Ishida, Junichi Kurihara, Fra Angelico Viray, Shielo Baes Namuco, Enrico C. Paringit, Gay Jane Perez, Yukihiro Takahashi, Joel Joseph Marciano
    Computers and Electronics in Agriculture 144 80 - 85 0168-1699 2018/01/01 [Not refereed][Not invited]
     
    The use of unmanned aerial vehicle (UAV)-based spectral imaging offers considerable advantages in high-resolution remote-sensing applications. However, the number of sensors mountable on a UAV is limited, and selecting the optimal combination of spectral bands is complex but crucial for conventional UAV-based multispectral imaging systems. To overcome these limitations, we adopted a liquid crystal tunable filter (LCTF), which can transmit selected wavelengths without the need to exchange optical filters. For calibration and validation of the LCTF-based hyperspectral imaging system, a field campaign was conducted in the Philippines during March 28–April 3, 2016. In this campaign, UAV-based hyperspectral imaging was performed in several vegetated areas, and the spectral reflectances of 14 different ground objects were measured. Additionally, the machine learning (ML) approach using a support vector machine (SVM) model was applied to the obtained dataset, and a high-resolution classification map was then produced from the aerial hyperspectral images. The results clearly showed that a large amount of misclassification occurred in shaded areas due to the difference in spectral reflectance between sunlit and shaded areas. It was also found that the classification accuracy was drastically improved by training the SVM model with both sunlit and shaded spectral data. As a result, we achieved a classification accuracy of 94.5% in vegetated areas.
  • Oyama Shin-ichiro, Kubota Ken, Morinaga Takatoshi, Tsuda Takuo T, Kurihara Junichi, Larsen Miguel F, Yamamoto Masayuki, Cai Lei
    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 122 (10) 10864-10875  2169-9380 2017/10/13 [Not refereed][Not invited]
  • Shin-ichiro Oyama, Kazuo Shiokawa, Yoshizumi Miyoshi, Keisuke Hosokawa, Brenton J. Watkins, Junichi Kurihara, Takuo T. Tsuda, Christopher T. Fallen
    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 121 (4) 3564 - 3577 2169-9380 2016/04 [Refereed][Not invited]
     
    Measurements of the lower thermospheric wind with a Fabry-Perot interferometer (FPI) at Tromso, Norway, found the largest wind variations in a night during the appearance of auroral patches at the substorm recovery phase. Taking into account magnetospheric substorm evolution of plasma energy accumulation and release, the largest wind amplitude at the recovery phase is a fascinating result. The results are the first detailed investigation of the magnetosphere-ionosphere-thermosphere coupled system at the substorm recovery phase using comprehensive data sets of solar wind, geomagnetic field, auroral pattern, and FPI-derived wind. This study used three events in November 2010 and January 2012, particularly focusing on the wind signatures associated with the auroral morphology, and found three specific features: (1) wind fluctuations that were isolated at the edge and/or inthe darker area of an auroral patchwith the largest vertical amplitude up to about 20m/s and with the longest oscillation period about 10min, (2) when the convection electric field was smaller than 15mV/m, and (3) wind fluctuations that were accompanied by pulsating aurora. This approach suggests that the energy dissipation to produce the wind fluctuations is localized in the auroral pattern. Effects of the altitudinal variation in the volume emission rate were investigated to evaluate the instrumental artifact due to vertical wind shear. The small electric field values suggest weak contributions of the Joule heating and Lorentz force processes in wind fluctuations. Other unknown mechanisms may play a principal role at the recovery phase.
  • Development and Flight Results of Microsatellite Bus System for RISING-2
    Yuji SAKAMOTO, Nobuo SUGIMURA, Kazufumi FUKUDA, Toshinori KUWAHARA, Kazuya YOSHIDA, Junichi KURIHARA, Tetsuya FUKUHARA, Yukihiro TAKAHASHI
    Transactions of Japan Society for Aeronautical and Space Science (JSASS) Aerospace Technology Japan, 14, ists30 (2016), Pf_89-Pf_96. 2016 [Refereed][Not invited]
  • S. Oyama, Y. Miyoshi, K. Shiokawa, J. Kurihara, T. T. Tsuda, B. J. Watkins
    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 119 (5) 4146 - 4156 2169-9380 2014/05 [Refereed][Not invited]
     
    High-latitude ionospheric variations at times near auroral substorms exhibit large temporal variations in both vertical and horizontal extents. Statistical analysis was made of data from the European Incoherent Scatter UHF radar at TromsO, Norway, and International Monitor for Auroral Geomagnetic Effects magnetometer for finding common features in electron density, ion and electron temperatures and relating these to currents and associated heating. This paper particularly focused on the height dependencies. Results show clear evidences of large electric field with corresponding frictional heating and Pedersen currents located just outside the front of the poleward expanding aurora, which typically appeared at the eastside of westward traveling surge. At the beginning of the substorm recovery phase, the ionospheric density had a large peak in the E region and a smaller peak in the F region. This structure was named as C form in this paper based on its shape in the altitude-time plot. The lower altitude density maximum is associated with hard auroral electron precipitation probably during pulsating aurora. We attribute the upper F region density maximum to local ionization by lower energy particle precipitation and/or long-lived plasma that is convected horizontally into the overhead measurement volume from the dayside hemisphere.
  • S. Oyama, Y. Miyoshi, K. Shiokawa, J. Kurihara, T. T. Tsuda, B. J. Watkins
    Journal of Geophysical Research: Space Physics 119 (5) 4146 - 4156 2169-9402 2014 [Refereed][Not invited]
     
    High-latitude ionospheric variations at times near auroral substorms exhibit large temporal variations in both vertical and horizontal extents. Statistical analysis was made of data from the European Incoherent Scatter UHF radar at Tromsø, Norway, and International Monitor for Auroral Geomagnetic Effects magnetometer for finding common features in electron density, ion and electron temperatures and relating these to currents and associated heating. This paper particularly focused on the height dependencies. Results show clear evidences of large electric field with corresponding frictional heating and Pedersen currents located just outside the front of the poleward expanding aurora, which typically appeared at the eastside of westward traveling surge. At the beginning of the substorm recovery phase, the ionospheric density had a large peak in the E region and a smaller peak in the F region. This structure was named as C form in this paper based on its shape in the altitude-time plot. The lower altitude density maximum is associated with hard auroral electron precipitation probably during pulsating aurora. We attribute the upper F region density maximum to local ionization by lower energy particle precipitation and/or long-lived plasma that is convected horizontally into the overhead measurement volume from the dayside hemisphere. Key Points Ionosphere near poleward moving aurora is studied using EISCAT data Joule energy is dissipated just outside the poleward expanding aurora Ionospheric density at early recovery phase has a double peak in height ©2014. American Geophysical Union. All Rights Reserved.
  • 火星大気散逸観測オービター計画の検討
    松岡 彩子, 阿部 琢美, 関 華奈子, 寺田 直樹, 石坂 圭吾, 小倉 聡司, 川勝 康弘, 熊本 篤志, 栗原 純一, 坂野井 健, 田口 真, 中川 広務, 平原 聖文, 二穴 喜文, 八木谷 聡, 山崎 敦, 横田 勝一郎
    第14回宇宙科学シンポジウム 講演集 2014 [Not refereed][Not invited]
  • Constellation of Earth Observation Micro-satellites with Multi-spectral High-resolution Telescopes
    Toshinori Kuwahara, Kazuya Yoshida, Yuji Sakamoto, Yoshihiro Tomioka, Kazufumi Fukuda, Nobuo Sugimura, Junichi Kurihara, Tetsuya Fukuhara, Yukihiro Takahashi
    27th Annual AIAA/ASU Conference on Small Satellites (SSC13-IV-7) 1 - 6 2013/08/13 [Refereed][Not invited]
  • Yoshiko Koizumi-Kurihara, Junichi Kurihara, Yasuhiro Murayama, Koh-Ichiro Oyama
    An Introduction to Space Instrumentation 41 - 46 2013 [Not refereed][Not invited]
  • N. Iwagami, Y. Koizumi-Kurihara, J. Kurihara
    An Introduction to Space Instrumentation 21 - 24 2013 [Not refereed][Not invited]
  • J. Kurihara, N. Iwagami, K.-I. Oyama
    An Introduction to Space Instrumentation 33 - 39 2013 [Not refereed][Not invited]
  • 火星大気散逸探査検討WG, 火星大気散逸観測オービター計画の検討
    松岡彩子, 阿部琢美, 関華奈子, 寺田直樹, 石坂圭吾, 熊本篤志, 栗原純一, 坂野井健, 田口真, 中川広務, 平原聖文, 二穴喜文, 八木谷聡, 山崎敦, 横田勝一郎
    火星大気散逸探査検討WG, 火星大気散逸観測オービター計画の検討 2013 [Not refereed][Not invited]
  • S. Oyama, J. Kurihara, B. J. Watkins, T. T. Tsuda, T. Takahashi
    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 117 2169-9380 2012/05 [Refereed][Not invited]
     
    The ion-neutral collision frequency in the lower ionosphere (106-135 km) was estimated using data from the European Incoherent Scatter (EISCAT) radar at Tromso, Norway during the Dynamics and Energetics of the Lower Thermosphere in Aurora 2 (DELTA-2) campaign in 2009. Vertical component of the ion velocity was used with the ion momentum equation for the calculations. The ion-neutral collision frequency was found to be approximately equivalent to that predicted using modeled density data. However, notable increases were found above 126.8 km during natural ionospheric heating events. A depression in calculated values was also found between 114.6 km and 126.8 km just after cessation of a heating event. This paper discusses contributions of the vertical thermospheric motion to variations of the ion-neutral collision frequency.
  • S. Oyama, J. Kurihara, B. J. Watkins, T. T. Tsuda, T. Takahashi
    Journal of Geophysical Research: Space Physics 117 (5) 2169-9402 2012 [Refereed][Not invited]
     
    The ion-neutral collision frequency in the lower ionosphere (106-135 km) was estimated using data from the European Incoherent Scatter (EISCAT) radar at Troms, Norway during the Dynamics and Energetics of the Lower Thermosphere in Aurora 2 (DELTA-2) campaign in 2009. Vertical component of the ion velocity was used with the ion momentum equation for the calculations. The ion-neutral collision frequency was found to be approximately equivalent to that predicted using modeled density data. However, notable increases were found above 126.8 km during natural ionospheric heating events. A depression in calculated values was also found between 114.6 km and 126.8 km just after cessation of a heating event. This paper discusses contributions of the vertical thermospheric motion to variations of the ion-neutral collision frequency. Copyright 2012 by the American Geophysical Union.
  • A Japanese Microsatellite Bus System for International Scientific Missions,
    Toshinori Kuwahara, Kazuya Yoshida, Yuji Sakamoto, Yukihiro Takahashi, Junichi Kurihara, Hiroshi Yamakawa, Atsushi Takada
    62nd International Astronautical Congres, Cape Town, Oct. 2011, IAC-11.B4.2.10. 2011/10 [Not refereed][Not invited]
  • S. Oyama, A. Brekke, T. T. Tsuda, J. Kurihara, B. J. Watkins
    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 116 2169-9380 2011/07 [Refereed][Not invited]
     
    The vertical component of the ion velocity measured with the European Incoherent Scatter (EISCAT) Tromso UHF radar (69.6 degrees N, 19.2 degrees E) in the lower ionosphere (from 95 to 130 km) was found to be characterized by notably large variances at oscillation periods of 2-8 min. Of particular interest was the geomagnetic activity dependence above similar to 106 km, which showed larger variances (100-500 m(2) s(2)) during periods of geomagnetic disturbance than during quiet periods. Below 106 km, the variance was less sensitive to the geomagnetic activity. Height profiles of the variance during the disturbed period showed steep increases with heights above 106 km, then reaching a peak at 120 km, where the ion gyrofrequency is equal to the modeled ion-neutral collision frequency. A theoretical prediction well reproduced the height profile for the geomagnetically disturbed period by assuming oscillations in the meridional component of the electric field. The theoretical study suggested that the electric field oscillation is a possible cause of large variances of the vertical ion speed in the polar lower ionosphere. However, below 106 km, other mechanisms were necessary.
  • Development Status and Operation Plan of 50-kg Microsatellite RISING-2 for Earth Observations by Multi-Spectrum Instruments
    Yuji Sakamoto, Toshinori Kuwahara, Kazufumi Fukuda, Kazuya Yoshida, Tetsuya Fukuhara, Junichi Kurihara, Yukihiro Takahashi
    Proceedings of the 28th International Symposium on Space Technology and Science 2011/06 [Refereed][Not invited]
  • Mission and System of the Earth Observation Microsatellite RISING-2
    Toshinori Kuwahara, Yuji Sakamoto, Kazuya Yoshida, Yukihiro Takahashi, Tetsuya Fukuhara, Junichi Kurihara
    Proceedings of the 8th IAA Symposium on Small Satellites for Earth Observation 2011/04 [Refereed][Not invited]
  • International Scientific Missions on a Japan-led Micro-satellite
    Toshinori Kuwahara, Kazuya Yoshida, Yuji Sakamoto, Yukihiro Takahashi, Junichi Kurihara, Hiroshi Yamakawa, Atsushi Takada
    2nd Nano-Satellite Symposium 2011/03 [Refereed][Not invited]
  • S. Oyama, A. Brekke, T. T. Tsuda, J. Kurihara, B. J. Watkins
    Journal of Geophysical Research: Space Physics 116 (7) 2169-9402 2011 [Refereed][Not invited]
     
    The vertical component of the ion velocity measured with the European Incoherent Scatter (EISCAT) Troms UHF radar (69.6°N, 19.2°E) in the lower ionosphere (from 95 to 130 km) was found to be characterized by notably large variances at oscillation periods of 2-8 min. Of particular interest was the geomagnetic activity dependence above ∼106 km, which showed larger variances (100-500 m2 s-2) during periods of geomagnetic disturbance than during quiet periods. Below 106 km, the variance was less sensitive to the geomagnetic activity. Height profiles of the variance during the disturbed period showed steep increases with heights above 106 km, then reaching a peak at 120 km, where the ion gyrofrequency is equal to the modeled ion-neutral collision frequency. A theoretical prediction well reproduced the height profile for the geomagnetically disturbed period by assuming oscillations in the meridional component of the electric field. The theoretical study suggested that the electric field oscillation is a possible cause of large variances of the vertical ion speed in the polar lower ionosphere. However, below 106 km, other mechanisms were necessary. Copyright 2011 by the American Geophysical Union.
  • J. Kurihara, Y. Koizumi-Kurihara, N. Iwagami, T. Suzuki, A. Kumamoto, T. Ono, M. Nakamura, M. Ishii, A. Matsuoka, K. Ishisaka, T. Abe, S. Nozawa
    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 115 0148-0227 2010/12 [Refereed][Not invited]
     
    To study the spatial structure of midlatitude sporadic E (E(s)) layers, the ultraviolet resonant scattering by magnesium ions (Mg(+)) in an E(s) layer was observed during the evening twilight with the Magnesium Ion Imager (MII) on the sounding rocket launched from the Uchinoura Space Center in Kagoshima, Japan. The in situ electron density measured by an onboard impedance probe showed that the E(s) layer was located at an altitude of 100 km during both the ascent and descent of the flight. Simultaneous observation with a ground-based ionosonde at Yamagawa identified the signature of horizontally "patchy" structures in the E(s) layer. The MII successfully scanned the horizontal Mg(+) density perturbations in the E(s) layer and found that they had patchy and frontal structures. The horizontal scale and alignment of the observed frontal structure is generally consistent with a proposed theory. To our knowledge, this is the first observation of the two-dimensional horizontal structure of Mg(+) in an E(s) layer.
  • J. Kurihara, Y. Ogawa, S. Oyama, S. Nozawa, M. Tsutsumi, C. M. Hall, Y. Tomikawa, R. Fujii
    Geophysical Research Letters 37 (13) 0094-8276 2010/07/01 [Refereed][Not invited]
     
    We analyzed neutral winds, ambipolar diffusion coefficients, and neutral temperatures observed by the Nippon/Norway Troms Meteor Radar (NTMR) and ion temperatures observed by the European Incoherent Scatter (EISCAT) UHF radar at Troms (69.6N, 19.2E), during a major stratospheric sudden warming (SSW) that occurred in January 2009. The zonal winds at 80-100 km height reversed approximately 10 days earlier than the zonal wind reversal in the stratosphere and the neutral temperature at 90 km decreased simultaneously with the zonal wind reversal at the same altitude. We found different variations between geomagnetically quiet nighttime ion temperatures at 101-110 km and 120-142 km for about 10 days around the SSW. Our results from the ground-based observations agree well with the satellite observations shown in an accompanying paper. Thus, this study indicates that a SSW is strongly linked to thermal structure and dynamics in the high-latitude mesosphere, lower thermosphere, and ionosphere. © 2010 by the American Geophysical Union.
  • J. Kurihara, Y. Koizumi-Kurihara, N. Iwagami, T. Suzuki, A. Kumamoto, T. Ono, M. Nakamura, M. Ishii, A. Matsuoka, K. Ishisaka, T. Abe, S. Nozawa
    Journal of Geophysical Research: Space Physics 115 (12) 2169-9402 2010 [Refereed][Not invited]
     
    To study the spatial structure of midlatitude sporadic E (Es) layers, the ultraviolet resonant scattering by magnesium ions (Mg+) in an Es layer was observed during the evening twilight with the Magnesium Ion Imager (MII) on the sounding rocket launched from the Uchinoura Space Center in Kagoshima, Japan. The in situ electron density measured by an onboard impedance probe showed that the Es layer was located at an altitude of 100 km during both the ascent and descent of the flight. Simultaneous observation with a ground-based ionosonde at Yamagawa identified the signature of horizontally "patchy" structures in the Es layer. The MII successfully scanned the horizontal Mg+ density perturbations in the Es layer and found that they had patchy and frontal structures. The horizontal scale and alignment of the observed frontal structure is generally consistent with a proposed theory. To our knowledge, this is the first observation of the two-dimensional horizontal structure of Mg + in an Es layer. Copyright 2010 by the American Geophysical Union.
  • S. Oyama, K. Shiokawa, J. Kurihara, T. T. Tsuda, S. Nozawa, Y. Ogawa, Y. Otsuka, B. J. Watkins
    ANNALES GEOPHYSICAE 28 (10) 1847 - 1857 0992-7689 2010 [Refereed][Not invited]
     
    Simultaneous observations were conducted with a Fabry-Perot Interferometer (FPI) at a wavelength of 557.7 nm, an all-sky camera at a wavelength of 557.7 nm, and the European Incoherent Scatter (EISCAT) UHF radar during the Dynamics and Energetics of the Lower Thermosphere in Aurora 2 (DELTA-2) campaign in January 2009. This paper concentrated on two events during periods of pulsating aurora. The lower-thermospheric wind velocity measured with the FPI showed obvious fluctuations in both vertical and horizontal components. Of particular interest is that the location of the fluctuations was found in a darker area that appeared within the pulsating aurora. During the same time period, the EISCAT radar observed sporadic enhancements in the F-region backscatter echo power, which suggests the presence of low-energy electron (1 keV or lower) precipitation coinciding with increase in amplitude of the electromagnetic wave (at the order of 10 Hz or higher). While we have not yet identified the dominant mechanism causing the fluctuations in FPI-derived wind velocity during the pulsating aurora, the frictional heating energy dissipated by the electric-field perturbations may be responsible for the increase in ionospheric thermal energy thus modifying the local wind dynamics in the lower thermosphere.
  • J. Kurihara, S. Oyama, S. Nozawa, T. T. Tsuda, R. Fujii, Y. Ogawa, H. Miyaoka, N. Iwagami, T. Abe, K. I. Oyama, M. J. Kosch, A. Aruliah, E. Griffin, K. Kauristie
    Journal of Geophysical Research: Space Physics 114 (12) 0148-0227 2009/12 [Refereed][Not invited]
     
    A coordinated observation of the atmospheric response to auroral energy input in the polar lower thermosphere was conducted during the Dynamics and Energetics of the Lower Thermosphere in Aurora (DELTA) campaign. N2 rotational temperature was measured with a rocket-borne instrument launched from the Andøya Rocket Range, neutral winds were measured from auroral emissions at 557.7 nm with a Fabry-Perot Interferometer (FPI) at Skibotn and the KEOPS, and ionospheric parameters were measured with the European Incoherent Scatter (EISCAT) UHF radar at Tromsø. Altitude profiles of the passive energy deposition rate and the particle heating rate were estimated using data taken with the EISCAT radar. The local temperature enhancement derived from the difference between the observed N2 rotational temperature and the MSISE-90 model neutral temperature were 70-140 K at 110-140 km altitude. The temperature increase rate derived from the estimated heating rates, however, cannot account for the temperature enhancement below 120 km, even considering the contribution of the neutral density to the estimated heating rate. The observed upward winds up to 40 m s-1 seem to respond nearly instantaneously to changes in the heating rates. Although the wind speeds cannot be explained by the estimated heating rate and the thermal expansion hypothesis, the present study suggests that the generation mechanism of the large vertical winds must be responsible for the fast response of the vertical wind to the heating event. Copyright 2009 by the American Geophysical Union.
  • Kurihara, J, T. Abe, I. Murata, K. Sato, Y. Tomikawa
    Trans. JSASS Space Tech. Japan 7 Pm_7 - Pm_11 2009 [Refereed][Not invited]
  • Junichi Kurihara, Takumi Abe, Koh-Ichiro Oyama, Eoghan Griffin, Mike Kosch, Anasuya Aruliah, Kirsti Kauristie, Yasunobu Ogawa, Sayaka Komada, Naomoto Iwagami
    EARTH PLANETS AND SPACE 58 (9) 1123 - 1130 1343-8832 2006 [Refereed][Not invited]
     
    The rotational temperature and number density of molecular nitrogen (N(2)) in the lower thermosphere were measured by the N2 temperature instrument onboard the S-310-35 sounding rocket, which was launched from Andoya at 0:33 UT on 13 December 2004, during the Dynamics and Energetics of the Lower Thermosphere in Aurora (DELTA) campaign. The rotational temperature measured at altitudes between 95 and 140 km, which is expected to be equal to neutral temperature, is much higher than neutral temperature from the Mass Spectrometer Incoherent Scatter (MSIS) model. Neutral temperatures in the lower thermosphere were observed using the auroral green line at 557.7 nm by two Fabry-Perot Interferometers (FPIs) at Skibotn and the Kiruna Esrange Optical Platform System site. The neutral temperatures derived from the look directions closest to the rocket correspond to the rotational temperature measured at an altitude of 120 km. In addition, a combination of the all-sky camera images at 557.7 nm observed at two stations, Kilpisjarvi and Muonio, suggests that the effective altitude of the auroral arcs at the time of the launch is about 120 km. The FPI temperature observations are consistent with the in situ rocket observations rather than the MSIS model.
  • Takumi Abe, Junichi Kurihara, Naomoto Iwagami, Satonori Nozawa, Yasunobu Ogawa, Ryoichi Fujii, Hajime Hayakawa, Kon Ichiro Oyama
    Earth, Planets and Space 58 (9) 1165 - 1171 1343-8832 2006 [Refereed][Not invited]
     
    Japanese sounding rocket "S-310-35" was launched from Andøya Rocket Range in Norway on December 13, 2004 during Dynamics and Energetics of the Lower Thermosphere in Aurora (DELTA) campaign, in which the rocket-borne in-situ measurements and ground-based measurements were coordinated to carry out a comprehensive observation of the thermospheric response against the auroral energy input. The instruments on board the rocket successfully performed their measurements during the flight, and thereby the temperature and density of molecular nitrogen, auroral emission rate, and the ambient plasma parameters were derived. Simultaneous measurements by the ground-based instruments provided neutral wind, neutral temperature, the auroral images and the ionospheric parameters near the rocket trajectory. This paper introduces science objectives, experimental outline, and preliminary scientific results of the DELTA campaign and explains geophysical condition at the time of the rocket launch, while the companion papers in this special issue describe more detailed results from each instrument. 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.
  • Eoghan Griffin, Mike Kosch, Anasuya Aruliah, Andrew Kavanagh, Ian McWhirter, Andrew Senior, Elaina Ford, Chris Davis, Takumi Abe, Junichi Kurihara, Kirsti Kauristie, Yasunobu Ogawa
    EARTH PLANETS AND SPACE 58 (9) 1113 - 1121 1343-8832 2006 [Refereed][Not invited]
     
    The Japan Aerospace Exploration Agency (JAXA) DELTA rocket experiment, successfully launched from Andoya at 0033 UT on December 13, 2004, supported by ground based optical instruments, primarily 2 Fabry-Perot Interferometers (FPIs) located at Skibotn, Norway (69.3 degrees N, 20.4 degrees E) and the KEOPS Site, Esrange, Kiruna, Sweden (67.8 degrees N, 20.4 degrees E). Both these instruments sampled the 557.7 nm lower thermosphere atomic oxygen emission and provided neutral temperatures and line-of-sight wind velocities, with deduced vector wind patterns over each site. All sky cameras allow contextual auroral information to be acquired. The proximity of the sites provided overlapping fields of view, adjacent to the trajectory of the DELTA rocket. This allowed independent verification of the absolute temperatures in the relatively quiet conditions early in the night, especially important given the context provided by co-located EISCAT ion temperature measurements which allow investigation of the likely emission altitude of the passive FPI measurements. The results demonstrate that this altitude changes from 120 km pre-midnight to 115 km post-midnight. Within this large scale context the results from the FPIs also demonstrate smaller scale structure in neutral temperatures, winds and intensities consistent with localised heating. These results present a challenge to the representation of thermospheric variability for the existing models of the region.
  • S. Nozawa, Yasunobu Ogawa, A. Brekke, T. Tsuda, C. M. Hall, H. Miyaoka, J. Kurihara, Takumi Abe, R. Fujii
    Earth, Planets and Space 58 (9) 1183 - 1191 1343-8832 2006 [Refereed][Not invited]
     
    This paper aims at describing the ionospheric conditions during the DELTA (Dynamics and Energetics of the Lower Thermosphere in Aurora) campaign period based on EISCAT radar observations conducted at Tromsø (69.6°N, 19.2°E). We conducted EISCAT UHF radar observations on December 5 and from December 8 to December 13, 2004 with a beam-scanning mode for a total of 74 hours. Except for December 8 during a 2 hr interval operation, we operated the EISCAT UHF radar for 12 hour intervals everyday to make it possible to derive semidiurnal tidal amplitudes and phases in the lower thermosphere. Observed electron densities and derived electric fields by the EISCAT UHF radar indicate that magnetospheric activity was high during the period from December 5 to 13 except for the night of December 13. Derived semidiurnal amplitudes during December 9-12, 2004 exhibited a day to day variation at and below 110 km, while the corresponding phase was relatively stable over the four days except for the zonal component on December 12. Neutral and electron temperatures measured by the DELTA rocket were compared with neutral/ion and electron temperatures from the EISCAT UHF radar observations. Comparison of neutral/ion temperatures show some agreement, while poor agreements were found for the electron temperature. Possible causes of the discrepancy are discussed. 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.
  • J Kurihara, KI Oyama, N Iwagami, T Takahashi
    ANNALES GEOPHYSICAE 24 (1) 89 - 95 0992-7689 2006 [Refereed][Not invited]
     
    Numerical simulations using the Direct Simulation Monte Carlo (DSMC) method are known to be useful for analyses of aerodynamic effects on in-situ rocket measurements in the lower thermosphere, but the DSMC analysis of' a spin modulation caused by an asymmetric flow around the rocket spin axis has been restricted to the two-dimensional and axially symmetric simulations in actual sounding rocket experiments. This study provides a quantitative analysis of the spin modulation using a three-dimensional (3-D) simulation of the asymmetric flow with the DSMC method. Clear spin modulations in the lower thermospheric N-2 density measurement by a rocket-borne instrument are simulated using the rocket attitude and velocity, the simplified payload structure, and the approximated atmospheric conditions. Comparison between the observed and simulated spin modulations show a very good agreement within 5% at around 100 km. The results of the simulation are used to correct the spin modulations and derive the absolute densities in the background atmosphere.
  • J Kurihara, KI Oyama
    REVIEW OF SCIENTIFIC INSTRUMENTS 76 (8) 083101.1-083101.6  0034-6748 2005/08 [Not refereed][Not invited]
     
    We applied the electron beam fluorescence (EBF) technique to measure the vibrational temperature, rotational temperature, and number density of atmospheric molecular nitrogen (N-2) in the altitude range of 100-150 km. The atmospheric N-2 is excited and ionized by electron beam of the energy of 1 keV and the subsequent fluorescence of the N-2(+) first negative band is detected by a sensitive spectrometer, which covers the 360-440 nm wavelength range. In contrast to previous rocket-borne photometric measurements using the EBF technique, the spectrometric measurement provides the above three parameters simultaneously and more accurately. Preflight laboratory experiments were carried out in order to test the spectral sensitivity over the whole spectral range, to calibrate the number density from the band intensity, and to know the accuracy of the rotational temperature measurement. Finally, we tried to calibrate the vibrational temperature measurement by using heated N-2 gas which is ejected from the small nozzle. (c) 2005 American Institute of Physics.
  • T Abe, J Kurihara, N Iwagami, S Nozawa, Y Ogawa, R Fujii, H Miyaoka, T Aso, M Kosch, E Griffin, A Aruliah, W Singer, EV Thrane, H Hayakawa, K Oyama
    17th ESA Symposium on European Rocket and Balloon Programmes and Related Research 590 (SP-590) 601 - 605 0379-6566 2005 [Refereed][Not invited]
     
    The coordinated sounding rocket and ground-based observations were conducted in Norway on 13 December 2004. The main objective of this campaign is to elucidate the dynamics and energetics in the lower thermosphere associated with the auroral energy input. The instruments on board the rocket successfully performed their measurements, and provided the temperature and density of molecular nitrogen, auroral emission rate, and the ambient plasma parameters, while neutral wind, neutral temperature, the auroral images and the ionospheric parameters were observed by ground-based measurements. In this paper, we present a summary of this campaign and preliminary results.
  • J Kurihara, KI Oyama, Y Takahashi
    JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS 65 (5) 643 - 646 1364-6826 2003/03 [Refereed][Not invited]
     
    Recent spectral measurements of sprites and elves using imaging spectrometers have been limited to the red end of the spectrum (above 500 nm), while spectral information from the blue end of the spectrum has been measured only by bandpass-filtered photometers. Although the blue photometric data identified N-2 second positive and N-2(+) first negative band emissions, uncertainty remains in some measurements due to the small separation in the emission lines. Spectrally resolved measurements of the blue components, particularly the emissions of N-2(+) IN band, are very important because they indicate the existence of relatively high electron energies and high level of ionization at that altitude and therefore can be a great help in uncovering the generation mechanism for sprites. We have recently developed an intensified CCD slit spectrograph system with a peak sensitivity around 350 nm with a highly linear dispersion and a spectral resolution of 2 nm. (C) 2003 Elsevier Science Ltd. All rights reserved.
  • J Kurihara, KI Oyama, K Suzuki, N Iwagami
    MIDDLE ATMOSPHERE STRUCTURE AND DYNAMICS 32 (5) 725 - 729 0273-1177 2003 [Refereed][Not invited]
     
    The vibrational temperature (T-v), the rotational temperature (T-v) and the number density of atmospheric molecular nitrogen (N-2) were measured in situ by a sounding rocket S-310-30 in order to study the dynamics and energetics in the lower thermosphere. Atmospheric N-2 was ionized and excited using an, electron gun and the emission from N-2(+) 1st negative (IN) bands was measured by a sensitive spectrometer, T-v and T-r were determined by fitting the observed spectra to synthetic spectra, and the number density was deduced from the intensities of the spectrum. The improvements of the instrument and the preliminary results of the measurement are presented. (C) 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

Books etc

MISC

Awards & Honors

  • 2020/03 内閣府 第4回宇宙開発利用大賞「宇宙航空研究開発機構理事長賞」
     アジア諸国への超小型衛星技術教育と実利用ネットワークの構築 
    受賞者: 北海道大学大学院理学研究院;教授 高橋幸弘;特任准教授 栗原純一;特任助教 石田哲朗;プログラムコーディネーター 百田恵理子;東北大学大学院工学研究科;教授 吉田和哉;特任准教授 坂本祐二;准教授 桒原聡文;特任助教 藤田伸哉

Research Grants & Projects

  • UAVハイパースペクトルリモートセンシングによる水稲の生育診断技術の開発
    日本学術振興会:科学研究費助成事業 基盤研究(C)
    Date (from‐to) : 2019/04 -2022/03 
    Author : 栗原 純一, 長田 亨
  • 極域下部熱圏における力学とエネルギー収支の研究
    日本学術振興会:科学研究費助成事業 特別研究員奨励費
    Date (from‐to) : 2007 -2009 
    Author : 栗原 純一
     
    本研究では、2004年12月に行われた国際協同観測「DELTAキャンペーン」の結果を踏まえて、Andoyaロケット実験場から打ち上げる観測ロケットによるin situ観測と、地上のFPIによる光学観測およびEISCATレーダーによるプラズマの電波観測を合わせた協同観測「DELTA-2キャンペーン」を行うことによって、オーロラ活動に伴う極域下部熱圏における大気擾乱現象の全体像の解明を目指している。特にDELTAキャンペーンで明らかになった中性大気温度・中性風速の擾乱について、その空間的な構造に着目して研究を行う。そのために、観測ロケットからTMA(トリメチルアルミニウム)を散布してロケットの軌道に沿って風速を測定することで、新たに水平風の鉛直構造を明らかにしたいと考えている。 2009年1月26日に観測ロケットS-310-39号機がノルウェーのAndoya実験場から打ち上げられ、TMAの放出および地上2地点からの観測に成功した。同時に搭載した窒素振動温度測定器は不具合によって期待された観測が行えなかったが、幸運にも観測ロケットの打ち上げ直後にオーロラブレークアップが発生し、オーロラブレークアップの前後でTMAによる下部熱圏の中性風観測を行うことができた。FPI光学観測およびEISCATレーダー観測も行われ、大変貴重な観測データが得られた。また、このキャンペーン期間中に成層圏突然昇温が発生したため、その関連性についても新たにテーマの一つとして加えて研究を行った。 研究計画の最終年度である本年度では、研究成果の公表を中心として、具体的には以下の研究活動を行った。1.国内学会における速報的な発表、2.研究協力者による初期解析結果についてのワークショップ、3.海外の国際学会における発表、4.学術論文による発表
  • Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2007 -2009 
    Author : HAYAKAWA Hajime, ABE Takumi, KURIHARA Yoshiko, KURIHARA Junichi
     
    To know how the respective ion species of thermal energy in the lower ionosphere obtain nonthermal energies is especially important for the understanding of the ion escape mechanisms in the polar ionosphere. We have developed a space-borne ion mass spectrometer for observations of the suprathermal ions related to the ion escape. In addition, we newly developed a low energy ion beam generator because ions of suprathermal energy are required for the laboratory calibration of the ion mass spectrometer.
  • 日本学術振興会:科学研究費助成事業 若手研究(B)
    Date (from‐to) : 2006 -2006 
    Author : 栗原 純一
     
    本研究では、これまで分からなかった電離圏E領域プラズマの3次元的な空間構造を明らかにすることを目的として、E領域に存在するマグネシウムイオン(Mg^+)からの共鳴散乱光を観測する気球搭載型イメージャを開発する。地球大気の電離圏E領域に、スポラディックE(Es)層と呼ばれる電子密度の非常に高い層が突発的に発生する現象がある。Es層には電子との再結合反応の遅いMg^+などの金属イオンが集積するため、Mg^+の3次元的な分布を知ることができれば、Es層内の電子密度の3次元構造がわかる。しかし、紫外域に輝線を持つMg^+の共鳴散乱光は、成層圏のオゾン層(高度25〜45km)による紫外光吸収を受けるので、本研究では到達高度50kmを越える高高度気球に搭載するMg^+共鳴散乱光イメージャを開発する。 本年度は、Mg^+共鳴散乱光観測からMg^+密度の3次元分布を推定する手法をシミュレーション計算によって検証した。朝夕の薄明時には太陽光の日陰境界線が刻々と変化するため、Mg^+による太陽光の共鳴散乱光を気球に搭載したイメージャで観測すると、Mg^+密度の3次元構造がスキャンされて得られる。計算の結果、観測されるMg^+共鳴散乱光の明るさは数100R程度で、オゾン層の吸収を避けるために必要な最低高度は40km、観測可能時間帯は太陽天頂角が95〜105°となる1時間程度であることがわかった。太陽天頂角の異なる時間に得られた画像の差分を得れば、鉛直分布が観測できることが示された。さらに、仮定したMg^+密度分布に水平方向の擾乱を与えることで、E領域プラズマの数十kmスケールの空間構造が充分に観測可能であることもわかった。以上の結果に基づいて、気球搭載型イメージャの光学系の検討を行い、仕様を決定した。これらの研究成果について、国内学会・シンポジウムで3件の研究発表を行った。


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