Updated on 2024/05/23

写真b

 
TAGUCHI Makoto
 
*Items subject to periodic update by Rikkyo University (The rest are reprinted from information registered on researchmap.)
Affiliation*
College of Science Department of Physics
Graduate School of Science Doctoral Program in Physics
Graduate School of Science Master's Program in Physics
Title*
Professor
Degree
博士(理学) ( 東北大学 )
Research Theme*
  • 地上及び飛翔体からの分光・撮像観測手法を用いて地球及び惑星超高層大気ダイナミクスを研究している。現在進めている主な研究課題は地上光学観測による地磁気共役点オーロラの研究、惑星大気・プラズマ観測用気球搭載望遠鏡の開発、金星探査機搭載赤外カメラによる金星大気ダイナミクスの研究、惑星コロナ観測用水素吸収セルの開発である。

  • Research Interests
  • Planetary Atmosphere Physics

  • Campus Career*
    • 4 2008 - Present 
      College of Science   Department of Physics   Professor
    • 4 2008 - Present 
      Graduate School of Science   Master's Program in Physics   Professor
    • 4 2008 - Present 
      Graduate School of Science   Doctoral Program in Physics   Professor
     

    Research Areas

    • Natural Science / Space and planetary sciences

    Research History

    • 4 2008 - Present 
      RIKKYO UNIVERSITY   Graduate School of Science Field of Study: Physics   Professor

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    • 4 2008 - Present 
      RIKKYO UNIVERSITY   Graduate School of Science Field of Study: Physics   Professor

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    • 4 2008 - Present 
      RIKKYO UNIVERSITY   College of Science Department of Physics   Professor

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    • 9 1996 - 3 2008 
      National Institute of Polar Research

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    • 1 1991 - 8 1996 
      Tohoku University   Faculty of Science

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    Education

    • - 1 1991 
      Tohoku University   Graduate School, Division of Natural Science

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      Country: Japan

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    • - 3 1989 
      Tohoku University   Graduate School, Division of Natural Science

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      Country: Japan

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    • - 3 1987 
      Tohoku University   Faculty of Science

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      Country: Japan

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    Committee Memberships

    • 2 2007 - 1 2009 
      地球電磁気・地球惑星圏学会   運営委員

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      Committee type:Academic society

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    Awards

    • 5 2022  
      Society of Geomagnetism and Earth, Planetary and Space Sciences  Tanakadate Awards  Study of Earth's and planetary atmospheres by spectroscopic observation
       
      Makoto Taguchi

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    • 1 2013  
      日本学術振興会  平成25年度科学研究費補助金特別研究員等審査会専門委員(書面担当) 表彰 
       
      田口 真

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      Award type:Other  Country:Japan

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    • 1 1999  
      U.S. Antarctic Program  Antarctic Service Medal of the United States of America 

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      Award type:Other  Country:United States

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    Papers

    • Spectroscopic and Imaging Observation of the Venus Atmosphere by a Balloon-Borne Stratospheric Telescope FUJIN-2 Peer-reviewed

      Masataka IMAI, Makoto TAGUCHI, Yasuhiro SHOJI, Toshihiko NAKANO, Yukihiro TAKAHASHI, Mitsuteru SATO, Tatsuharu OHNO, Kyoko TANAKA, Shion MORI, Daisuke KOHNO, Ko HAMAMOTO, Seiko TAKAGI

      Journal of Evolving Space Activities1   12 2023

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

      DOI: 10.57350/jesa.83

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    • In-orbit recalibration of Longwave Infrared Camera onboard Akatsuki Peer-reviewed

      Makoto Taguchi, Toru Kouyama, Temma Sugawa, Shin-ya Murakami, Masahiko Futaguchi

      Earth, Planets and Space   10 4 2023

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      Authorship:Lead author, Corresponding author   Publishing type:Research paper (scientific journal)  

      DOI: 10.1186/s40623-023-01803-w

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    • Correlation of Venusian Mesoscale Cloud Morphology Between Images Acquired at Various Wavelengths Peer-reviewed

      M. Narita, T. Imamura, Y. J. Lee, S. Watanabe, A. Yamazaki, T. Satoh, M. Taguchi, T. M. Sato, T. Fukuhara, M. Yamada, T. Kouyama, N. Iwagami

      Journal of Geophysical Research: Planets127 ( 6 )   6 2022

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

      DOI: 10.1029/2022je007228

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      Other Link: https://onlinelibrary.wiley.com/doi/full-xml/10.1029/2022JE007228

    • Horizontal structures of bow-shaped mountain wave trains seen in thermal infrared images of venusian clouds taken by Akatsuki LIR Peer-reviewed

      Kiichi Fukuya, Takeshi Imamura, Makoto Taguchi, Toru Kouyama

      Icarus378   114936 - 114936   5 2022

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      Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

      DOI: 10.1016/j.icarus.2022.114936

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    • Planetary‐Scale Waves Seen in Thermal Infrared Images of Venusian Cloud Top Peer-reviewed

      Naoya Kajiwara, Takeshi Imamura, Makoto Taguchi, Toru Kouyama

      Journal of Geophysical Research: Planets126 ( 12 )   12 2021

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      Publishing type:Research paper (scientific journal)   Publisher:American Geophysical Union ({AGU})  

      DOI: 10.1029/2021JE007047

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    • Temporal evolutions of N2+ Meinel (1,2) band near 1.5.μm associated with aurora breakup and their effects on mesopause temperature estimations from OH Meinel (3,1) band Peer-reviewed

      Takanori Nishiyama, Makoto Taguchi, Hidehiko Suzuki, Peter Dalin, Yasunobu Ogawa, Urban Brändström, Takeshi Sakanoi

      Earth, Planets and Space73 ( 1 )   12 2021

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      Publishing type:Research paper (scientific journal)  

      We have carried out ground-based NIRAS (Near-InfraRed Aurora and airglow Spectrograph) observations at Syowa station, Antarctic (69. 0 S , 39. 6 E) and Kiruna (67. 8 N , 20. 4 E), Sweden for continuous measurements of hydroxyl (OH) rotational temperatures and a precise evaluation of auroral contaminations to OH Meinel (3,1) band. A total of 368-nights observations succeeded for 2 winter seasons, and 3 cases in which N2+ Meinel (1,2) band around 1.5μm was significant were identified. Focusing on two specific cases, detailed spectral characteristics with high temporal resolutions of 30 s are presented. Intensities of N2+ band were estimated to be 228 kR and 217 kR just at the moment of the aurora breakup and arc intensification during pseudo breakup, respectively. At a wavelength of P (2) line (∼1523nm), N2+ emissions were almost equal to or greater than the OH line intensity. On the other hand, at a wavelength of P (4) line (∼1542nm), the OH line was not seriously contaminated and still dominant to N2+ emissions. Furthermore, we evaluated N2+ (1,2) band effects on OH rotational temperature estimations quantitatively for the first time. Auroral contaminations from N2+ (1,2) band basically lead negative bias in OH rotational temperature estimated by line-pair-ratio method with P (2) and P (4) lines in OH (3,1) band. They possibly cause underestimations of OH rotational temperatures up to 40 K. In addition, N2+ (1,2) band contaminations were temporally limited to a moment around the aurora breakup. This is consistent with proceeding studies reporting that enhancements of N2+ (1,2) band were observed associated with International Brightness Coefficient 2–3 auroras. It is also suggested that the contaminations would be neglected in the polar cap and the sub-auroral zone, where strong aurora intensification is less observed. Further spectroscopic investigations at these wavelengths are needed especially for more precise evaluations of N2+ (1,2) band contaminations. For example, simultaneous 2-D imaging observation and spectroscopic measurement with high spectral resolutions for airglow in OH (3,1) band will make great advances in more robust temperature estimations in the auroral zone.[Figure not available: see fulltext.]. ∘ ∘ ∘ ∘ 1 1 1 1

      DOI: 10.1186/s40623-021-01360-0

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    • Thermal Tides in the Upper Cloud Layer of Venus as Deduced From the Emission Angle Dependence of the Brightness Temperature by Akatsuki/LIR Peer-reviewed

      Masahiro Akiba, Makoto Taguchi, Tetsuya Fukuhara, Takeshi Imamura, Toru Kouyama, Takao M. Sato

      Journal of Geophysical Research: Planets126 ( 10 )   10 2021

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      Authorship:Corresponding author   Publishing type:Research paper (scientific journal)  

      The brightness temperature of the Venus disk obtained by Longwave Infrared Camera (LIR) on board Akatsuki shows clear limb darkening at low and middle latitudes. The profile of limb brightness reflects the vertical distributions of atmospheric temperature and the optical thickness of the cloud particles. Horizontal distributions of brightness temperature obtained by LIR during ∼5.8 Venusian years were analyzed to investigate the vertical structure of the brightness temperature distribution above the cloud tops based on the emission angle dependence of the sensing altitude. Emission angles were converted to sensing altitudes by a radiative transfer calculation with nominal temperature and cloud particle distributions based on past observations. We show a local time-altitude cross section of the brightness temperature deviation above the cloud tops for three latitudinal zones. The derived vertical amplitude distribution of the diurnal and semidiurnal tides above ∼68 km is mostly explained by the classical theory of thermal tides. A semidiurnal tide in which the phase shifts upstream with altitude is clearly seen in the equatorial region. By applying the dispersion relation of the internal gravity wave to the observed wave structure, it was found that the zonally averaged zonal wind velocity at altitudes of 66–71 km was approximately the same as the known superrotation velocity. By comparing the observed and simulated vertical phase structures, it is suggested that the tidal wave structure seen in the equatorial cloud tops is an aspect of upward propagation of a gravity wave generated in the upper cloud layer by solar heating.

      DOI: 10.1029/2020JE006808

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    • The nightside cloud-top circulation of the atmosphere of Venus Peer-reviewed

      Kiichi Fukuya, Takeshi Imamura, Makoto Taguchi, Tetsuya Fukuhara, Toru Kouyama, Takeshi Horinouchi, Javier Peralta, Masahiko Futaguchi, Takeru Yamada, Takao M. Sato, Atsushi Yamazaki, Shin ya Murakami, Takehiko Satoh, Masahiro Takagi, Masato Nakamura

      Nature595 ( 7868 ) 511 - 515   22 7 2021

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      Although Venus is a terrestrial planet similar to Earth, its atmospheric circulation is much different and poorly characterized1. Winds at the cloud top have been measured predominantly on the dayside. Prominent poleward drifts have been observed with dayside cloud tracking and interpreted to be caused by thermal tides and a Hadley circulation2–4; however, the lack of nightside measurements over broad latitudes has prevented the unambiguous characterization of these components. Here we obtain cloud-tracked winds at all local times using thermal infrared images taken by the Venus orbiter Akatsuki, which is sensitive to an altitude of about 65 kilometres5. Prominent equatorward flows are found on the nightside, resulting in null meridional velocities when these are zonally averaged. The velocity structure of the thermal tides was determined without the influence of the Hadley circulation. The semidiurnal tide was found to have an amplitude large enough to contribute to the maintenance of the atmospheric superrotation. The weakness of the mean meridional flow at the cloud top implies that the poleward branch of the Hadley circulation exists above the cloud top and that the equatorward branch exists in the clouds. Our results should shed light on atmospheric superrotation in other celestial bodies.

      DOI: 10.1038/s41586-021-03636-7

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    • Anomalously porous boulders on (162173) Ryugu as primordial materials from its parent body Peer-reviewed

      Sakatani, N., Tanaka, S., Okada, T., Fukuhara, T., Riu, L., Sugita, S., Honda, R., Morota, T., Kameda, S., Yokota, Y., Tatsumi, E., Yumoto, K., Hirata, N., Miura, A., Kouyama, T., Senshu, H., Shimaki, Y., Arai, T., Takita, J., Demura, H., Sekiguchi, T., Müller, T. G., Hagermann, A., Biele, J., Grott, M., Hamm, M., Delbo, M., Neumann, W., Taguchi, M., Ogawa, Y., Matsunaga, T., Wada, T., Hasegawa, S., Helbert, J., Hirata, N., Noguchi, R., Yamada, M., Suzuki, H., Honda, C., Ogawa, K., Hayakawa, M., Yoshioka, K., Matsuoka, M., Cho, Y., Sawada, H., Kitazato, K., Iwata, T., Abe, M., Ohtake, M., Matsuura, S., Matsumoto, K., Noda, H., Ishihara, Y., Yamamoto, K., Higuchi, A., Namiki, N., Ono, G., Saiki, T., Imamura, H., Takagi, Y., Yano, H., Shirai, K., Okamoto, C., Nakazawa, S., Iijima, Y., Arakawa, M., Wada, K., Kadono, T., Ishibashi, K., Terui, F., Kikuchi, S., Yamaguchi, T., Ogawa, N., Mimasu, Y., Yoshikawa, K., Takahashi, T., Takei, Y., Fujii, A., Takeuchi, H., Yamamoto, Y., Hirose, C., Hosoda, S., Mori, O., Shimada, T., Soldini, S., Tsukizaki, R., Ozaki, M., Tachibana, S., Ikeda, H., Ishiguro, M., Yabuta, H., Yoshikawa, M., Watanabe, S., Tsuda, Y.

      Nature Astronomy5 ( 8 ) 766 - 774   5 2021

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

      Planetesimals—the initial stage of the planetary formation process—are considered to be initially very porous aggregates of dusts<SUP>1,2</SUP>, and subsequent thermal and compaction processes reduce their porosity<SUP>3</SUP>. The Hayabusa2 spacecraft found that boulders on the surface of asteroid (162173) Ryugu have an average porosity of 30-50% (refs. <SUP>4-6</SUP>), higher than meteorites but lower than cometary nuclei<SUP>7</SUP>, which are considered to be remnants of the original planetesimals<SUP>8</SUP>. Here, using high-resolution thermal and optical imaging of Ryugu's surface, we discovered, on the floor of fresh small craters (&lt;20 m in diameter), boulders with reflectance (~0.015) lower than the Ryugu average<SUP>6</SUP> and porosity &gt;70%, which is as high as in cometary bodies. The artificial crater formed by Hayabusa2's impact experiment<SUP>9</SUP> is similar to these craters in size but does not have such high-porosity boulders. Thus, we argue that the observed high porosity is intrinsic and not created by subsequent impact comminution and/or cracking. We propose that these boulders are the least processed material on Ryugu and represent remnants of porous planetesimals that did not undergo a high degree of heating and compaction<SUP>3</SUP>. Our multi-instrumental analysis suggests that fragments of the highly porous boulders are mixed within the surface regolith globally, implying that they might be captured within collected samples by touch-down operations<SUP>10,11</SUP>....

      DOI: 10.1038/s41550-021-01371-7

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      Other Link: https://www.nature.com/articles/s41550-021-01371-7

    • Thermophysical Properties of C-Type Asteroid 162173 Ryugu Revealed by the Thermal Infrared Imager TIR on Hayabusa2

      Tatsuaki OKADA, Tetsuya FUKUHARA, Satoshi TANAKA, Makoto TAGUCHI, Takehiko ARAI, Hiroki SENSHU, Naoya SAKATANI, Yuri SHIMAKI, Hirohide DEMURA, Yoshiko OGAWA, Kohei KITAZATO, Kentaro SUKO, Tomohiko SEKIGUCHI, Toru KOUYAMA, Jun TAKITA, Tsuneo MATSUNAGA, Takeshi IMAMURA, Takehiko WADA, Sunao HASEGAWA, Jorn HELBERT, Thomas G. MUELLER, Axel HAGERMANN, Jens BIELE, Matthias GROTT, Maximilian HAMM, Marco DELBO, Naru HIRATA, Naoyuki HIRATA, Yukio YAMAMOTO, Fuyuto TERUI, Takanao SAIKI, Satoru NAKAZAWA, Makoto YOSHIKAWA, Seiichiro WATANABE, Yuichi TSUDA

      TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN19 ( 5 ) 654 - 659   2021

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      Publishing type:Research paper (scientific journal)   Publisher:Japan Society for Aeronautical and Space Sciences  

      DOI: 10.2322/tastj.19.654

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    • Thermophysical Properties of the Surface of Asteroid 162173 Ryugu: Infrared Observations and Thermal Inertia Mapping Peer-reviewed

      Yuri Shimaki, Hiroki Senshu, Naoya Sakatani, Tatsuaki Okada, Tetsuya Fukuhara, Satoshi Tanaka, Makoto Taguchi, Takehiko Arai, Hirohide Demura, Yoshiko Ogawa, Kentaro Suko, Tomohiko Sekiguchi, Toru Kouyama, Sunao Hasegawa, Jun Takita, Tsuneo Matsunaga, Takeshi Imamura, Takehiko Wada, Kohei Kitazato, Naru Hirata, Naoyuki Hirata, Rina Noguchi, Seiji Sugita, Shota Kikuchi, Tomohiro Yamaguchi, Naoko Ogawa, Go Ono, Yuya Mimasu, Kent Yoshikawa, Tadateru Takahashi, Yuto Takei, Atsushi Fujii, Hiroshi

      Icarus348   113835 - 113835   15 9 2020

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

      DOI: 10.1016/j.icarus.2020.113835

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    • How is the super-rotation of Venus’ atmosphere maintained by waves and turbulence Peer-reviewed

      Takeshi Horinouchi, Yoshi-Yuki Hayashi, Shigeto Watanabe, Manabu Yamada, Atsushi Yamazaki, Toru Kouyama, Makoto Taguchi, Tetsuya Fukuhara, Masahiro Takagi, Kazunori Ogohara, Shin-ya Murakami, Javier Peralta, Sanjay S. Limaye, Takeshi Imamura, Masato Nakamura, Takao M. Sato, Takehiko Satoh

      Science368 ( 6489 ) 405 - 409   24 4 2020

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      Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Association for the Advancement of Science (AAAS)  

      DOI: 10.1126/science.aaz4439

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    • Highly porous nature of a primitive asteroid revealed by thermal imaging Peer-reviewed

      Tatsuaki Okada, Tetsuya Fukuhara, Satoshi Tanaka, Makoto Taguchi, Takehiko Arai, Hiroki Senshu, Naoya Sakatani, Yuri Shimaki, Hirohide Demura, Yoshiko Ogawa, Kentaro Suko, Tomohiko Sekiguchi, Toru Kouyama, Jun Takita, Tsuneo Matsunaga, Takeshi Imamura, Takehiko Wada, Sunao Hasegawa, Joern Helbert, Thomas G. Mueller, Axel Hagermann, Jens Biele, Matthias Grott, Maximilian Hamm, Marco Delbo, Naru Hirata, Naoyuki Hirata, Yukio Yamamoto, Seiji Sugita, Noriyuki Namiki, Kohei Kitazato, Masahiko Arakawa, Shogo Tachibana, Hitoshi Ikeda, Masateru Ishiguro, Koji Wada, Chikatoshi Honda, Rie Honda, Yoshiaki Ishihara, Koji Matsumoto, Moe Matsuoka, Tatsuhiro Michikami, Akira Miura, Tomokatsu Morota, Hirotomo Noda, Rina Noguchi, Kazunori Ogawa, Kei Shirai, Eri Tatsumi, Hikaru Yabuta, Yasuhiro Yokota, Manabu Yamada, Masanao Abe, Masahiko Hayakawa, Takahiro Iwata, Masanobu Ozaki, Hajime Yano, Satoshi Hosoda, Osamu Mori, Hirotaka Sawada, Takanobu Shimada, Hiroshi Takeuchi, Ryudo Tsukizaki, Atsushi Fujii, Chikako Hirose, Shota Kikuchi, Yuya Mimasu, Naoko Ogawa, Go Ono, Tadateru Takahashi, Yuto Takei, Tomohiro Yamaguchi, Kent Yoshikawa, Fuyuto Terui, Takanao Saiki, Satoru Nakazawa, Makoto Yoshikawa, Seiichiro Watanabe, Yuichi Tsuda

      NATURE579 ( 7800 ) 518 - +   3 2020

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      Language:English   Publishing type:Research paper (scientific journal)   Publisher:NATURE PUBLISHING GROUP  

      Carbonaceous (C-type) asteroids(1) are relics of the early Solar System that have preserved primitive materials since their formation approximately 4.6 billion years ago. They are probably analogues of carbonaceous chondrites(2,3) and are essential for understanding planetary formation processes. However, their physical properties remain poorly known because carbonaceous chondrite meteoroids tend not to survive entry to Earth's atmosphere. Here we report on global one-rotation thermographic images of the C-type asteroid 162173 Ryugu, taken by the thermal infrared imager (TIR)(4) onboard the spacecraft Hayabusa2(5), indicating that the asteroid's boulders and their surroundings have similar temperatures, with a derived thermal inertia of about 300 J m(-2) s(-0.5) K-1 (300 tiu). Contrary to predictions that the surface consists of regolith and dense boulders, this low thermal inertia suggests that the boulders are more porous than typical carbonaceous chondrites(6) and that their surroundings are covered with porous fragments more than 10 centimetres in diameter. Close-up thermal images confirm the presence of such porous fragments and the flat diurnal temperature profiles suggest a strong surface roughness effect(7,8). We also observed in the close-up thermal images boulders that are colder during the day, with thermal inertia exceeding 600 tiu, corresponding to dense boulders similar to typical carbonaceous chondrites(6). These results constrain the formation history of Ryugu: the asteroid must be a rubble pile formed from impact fragments of a parent body with microporosity(9) of approximately 30 to 50 per cent that experienced a low degree of consolidation. The dense boulders might have originated from the consolidated innermost region or they may have an exogenic origin. This high-porosity asteroid may link cosmic fluffy dust to dense celestial bodies(10).Thermal imaging data obtained from the spacecraft Hayabusa2 reveal that the carbonaceous asteroid 162173 Ryugu is an object of unusually high porosity.

      DOI: 10.1038/s41586-020-2102-6

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    • Influence of the cloud-level neutral layer on the vertical propagation of topographically generated gravity waves on Venus Peer-reviewed

      Takeru Yamada, Takeshi Imamura, Tetsuya Fukuhara, Makoto Taguchi

      Earth Planets Space71 ( 1 )   20 11 2019

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

      Abstract

      The reason for stationary gravity waves at Venus’ cloud top to appear mostly at low latitudes in the afternoon is not understood. Since a neutral layer exists in the lower part of the cloud layer, the waves should be affected by the neutral layer before reaching the cloud top. To what extent gravity waves can propagate vertically through the neutral layer has been unclear. To examine the possibility that the variation of the neutral layer thickness is responsible for the dependence of the gravity wave activity on the latitude and the local time, we investigated the sensitivity of the vertical propagation of gravity waves on the neutral layer thickness using a numerical model. The results showed that stationary gravity waves with zonal wavelengths longer than 1000 km can propagate to the cloud-top level without notable attenuation in the neutral layer with realistic thicknesses of 5–15 km. This suggests that the observed latitudinal and local time variation of the gravity wave activity should be attributed to processes below the cloud. An analytical approach also showed that gravity waves with horizontal wavelengths shorter than tens of kilometers would be strongly attenuated in the neutral layer; such waves should originate in the altitude region above the neutral layer.

      DOI: 10.1186/s40623-019-1106-7

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      Other Link: http://link.springer.com/article/10.1186/s40623-019-1106-7/fulltext.html

    • Global Structure of Thermal Tides in the Upper Cloud Layer of Venus Revealed by LIR on Board Akatsuki Peer-reviewed

      T. Kouyama, M. Taguchi, T. Fukuhara, T. Imamura, T. Horinouchi, T. M. Sato, S. Murakami, G. L. Hashimoto, Y. J. Lee, M. Futaguchi, T. Yamada, M. Akiba, T. Satoh, M. Nakamura

      Geophysical Research Letters46 ( 16 ) 9457 - 9465   28 8 2019

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

      DOI: 10.1029/2019GL083820

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    • Thermal Inertia of C-Type Near-Earth Asteroid 162173 Ryugu Determined from the Dawn Side Observations by Thermal Infrared Imager

      Okada, T, Fukuhara, T, Tanaka, S, Taguchi, M, Arai, T, Sakatani, N, Shimaki, Y, Senshu, H, Demura, H, Ogawa, Y, Suko, K, Sekiguchi, T, Kouyama, T, Helbert, J, Mueller, T. G, Hagermann, A, Biele, J, Grott, M, Hamm, M, Delbo, M

      The Meteoritical Society 20192157 ( 2019 ) 6303 - 6303   7 2019

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      Language:English   Publishing type:Research paper (bulletin of university, research institution)  

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    • Stationary Features at the Cloud Top of Venus Observed by Ultraviolet Imager Onboard Akatsuki Peer-reviewed

      Takehiko Kitahara, Takeshi Imamura, Takao M. Sato, Atsushi Yamazaki, Yeon Joo Lee, Manabu Yamada, Shigeto Watanabe, Makoto Taguchi, Tetsuya Fukuhara, Toru Kouyama, Shin‐ya Murakami, George L. Hashimoto, Kazunori Ogohara, Hiroki Kashimura, Takeshi Horinouchi, Masahiro Takagi

      Journal of Geophysical Research: Planets124   15 5 2019

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

      DOI: 10.1029/2018JE005842

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    • The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes Peer-reviewed

      S. Sugita, R. Honda, T. Morota, S. Kameda, H. Sawada, E. Tatsumi, M. Yamada, C. Honda, Y. Yokota, T. Kouyama, N. Sakatani, K. Ogawa, H. Suzuki, T. Okada, N. Namiki, S. Tanaka, Y. Iijima, K. Yoshioka, M. Hayakawa, Y. Cho, M. Matsuoka, N. Hirata, N. Hirata, H. Miyamoto, D. Domingue, M. Hirabayashi, T. Nakamura, T. Hiroi, T. Michikami, P. Michel, R.-L. Ballouz, O. S. Barnouin, C. M. Ernst, S. E. Schröder, H. Kikuchi, R. Hemmi, G. Komatsu, T. Fukuhara, M. Taguchi, T. Arai, H. Senshu, H. Demura, Y. Ogawa, Y. Shimaki, T. Sekiguchi, T. G. Müller, A. Hagermann, T. Mizuno, H. Noda, K. Matsumoto, R. Yamada, Y. Ishihara, H. Ikeda, H. Araki, K. Yamamoto, S. Abe, F. Yoshida, A. Higuchi, S. Sasaki, S. Oshigami, S. Tsuruta, K. Asari, S. Tazawa, M. Shizugami, J. Kimura, T. Otsubo, H. Yabuta, S. Hasegawa, M. Ishiguro, S. Tachibana, E. Palmer, R. Gaskell, L. Le Corre, R. Jaumann, K. Otto, N. Schmitz, P. A. Abell, M. A. Barucci, M. E. Zolensky, F. Vilas, F. Thuillet, C. Sugimoto, N. Takaki, Y. Suzuki, H. Kamiyoshihara, M. Okada, K. Nagata, M. Fujimoto, M. Yoshikawa, Y. Yamamoto, K. Shirai, R. Noguchi, N. Ogawa, F. Terui, S. Kikuchi, T. Yamaguchi, Y. Oki, Y. Takao, H. Takeuchi, G. Ono, Y. Mimasu, K. Yoshikawa, T. Takahashi, Y. Takei, A. Fujii, C. Hirose, S. Nakazawa, S. Hosoda, O. Mori, T. Shimada, S. Soldini, T. Iwata, M. Abe, H. Yano, R. Tsukizaki, M. Ozaki, K. Nishiyama, T. Saiki, S. Watanabe, Y. Tsuda

      Science364   19 3 2019

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

      DOI: 10.1126/science.aaw0422

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    • Surface Physical Condition of Asteroid Ryugu Using Close-up Optical and Thermal Images

      Sakatani, N, Sugita, S, Honda, R, Morota, T, Yamada, M, Kameda, S, Tatsumi, E, Yokota, Y, Kouyama, T, Suzuki, H, Honda, C, Hayakawa, M, Yoshioka, K, Matsuoka, M, Cho, Y, Sawada, H, Ogawa, N, Miura, A, Okada, T, Tanaka, S, Senshu, H, Arai, T, Demura, H, Suko, K, Shimaki, Y, Sekiguchi, T, Takita, J, Fukuhara, T, Taguchi, M, Mueller, T, Hagermann, A, Biele, J, Grott, M, Delbo, M

      50th Lunar and Planetary Science Conference2132   1732 - 1733   3 2019

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    • Characteristics Evaluation and Performance Improvement Method of Balloon-Borne Telescope Pointing Control System

      Toshihiko NAKANO, Makoto TAGUCHI, Yasuhiro SHOJI, Mao TAKAMURA, Daiki SUNAGUCHI, Masataka IMAI, Makoto WATANABE, Yukihiro TAKAHASHI, Yuji SAKAMOTO, Kazuya YOSHIDA

      TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN17 ( 1 ) 51 - 56   2019

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      Publishing type:Research paper (scientific journal)   Publisher:Japan Society for Aeronautical and Space Sciences  

      DOI: 10.2322/tastj.17.51

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    • Exploring the Atmosphere of Mars with Remote Observations and Numerical Studies: Belgium-Japan partnership 2017-2019, and the Next

      Kasaba, Y, H. Nakagawa, H. Sagawa, T. Kuroda, T. Imamura, Y. Kasai, A. Yamazaki, T.M. Sato, H. Maezawa, M. Taguchi, H. Kashimura, I. Murata, N. Terada, T. Sakanoi, A.C. Vandaele, S. Aoki, S. Robert, V. Wilquet, A. Mahieux, S. Bauduin, F. Daerden, L. Neary, S. Viscardy, P.F. Coheur

      Proceedings of Symposium on Planetary Science 2019   2019

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    • Earth and moon observations by thermal infrared imager on Hayabusa2 and the application to detectability of asteroid 162173 Ryugu Peer-reviewed

      Tatsuaki Okada, Tetsuya Fukuhara, Satoshi Tanaka, Makoto Taguchi, Takehiko Arai, Hiroki Senshu, Hirohide Demura, Yoshiko Ogawa, Toru Kouyama, Naoya Sakatani, Jun Takita, Tomohiko Sekiguchi, Jorn Helbert, Thomas G. Mueller, Axel Hagermann, Hayabusa2 TIR Team

      Planetary and Space Science158   46 - 52   1 9 2018

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

      Thermal Infrared Imager TIR on Hayabusa2 has proven its in-flight performance to detect celestial bodies during the cruise phase, especially by the observations of the Earth and the Moon before and after the Earth swing-by on 3rd of December 2015. The result indicates that the target C-type asteroid 162173 Ryugu will be detected from the distance of 3000 km at the beginning of the approach phase, and that a C-type small moon larger than 1 m will be detected from the home position, 20 km from the asteroid, if it orbits around the asteroid.

      DOI: 10.1016/j.pss.2018.05.007

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    • Thermal Infrared Imager TIR on Hayabusa2 and Its Preparation for Asteroid Proximity Phase Operations Around 162173 Ryugu

      Okada, T, Fukuhara, T, Tanaka, S, Taguchi, M, Arai, T, Senshu, H, Sakatani, N, Ogawa, Y, Demura, H, Kitazato, K, Kouyama, T, Sekiguchi, T, Hasegawa, S, Matsunaga, T, Wada, T, Imamura, T, Takita, J, Shimaki, Y, Kyoda, H, Aoki, Y, Helbert, J, Mueller, T. G, Hagermann, A

      49th Lunar and Planetary Science Conference2083 ( 1403 )   3 2018

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    • Evaluation of hydrogen absorption cells for observations of the planetary coronas Peer-reviewed

      M. Kuwabara, M. Taguchi, K. Yoshioka, T. Ishida, N. De Oliveira, K. Ito, S. Kameda, F. Suzuki, I. Yoshikawa

      Review of Scientific Instruments89 ( 2 ) 023111-1 - 023111-10   1 2 2018

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      Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Institute of Physics Inc.  

      Newly designed Lyman-alpha absorption cells for imaging hydrogen planetary corona were characterized using an ultra high resolution Fourier transform spectrometer installed on the DESIRS (Dichroïsme Et Spectroscopie par Interaction avec le Rayonnement Synchrotron) beamline of Synchrotron SOLEIL in France. The early absorption cell installed in the Japanese Mars orbiter NOZOMI launched in 1998 had not been sufficiently optimized due to its short development time. The new absorption cells are equipped with the ability to change various parameters, such as filament shape, applied power, H2 gas pressure, and geometrical configuration. We found that the optical thickness of the new absorption cell was ∼4 times higher than the earlier one at the center wavelength of Lyman-alpha absorption, by optimizing the condition to promote thermal dissociation of H2 molecules into two H atoms on a hot tungsten filament. The Doppler temperature of planetary coronas could be determined with an accuracy better than 100 K with the performance of the newly developed absorption cell.

      DOI: 10.1063/1.5007812

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    • Venus looks different from day to night across wavelengths: morphology from Akatsuki multispectral images Peer-reviewed

      Limaye S. S, Watanabe S, Yamazaki A, Yamada M, Satoh T, Sato T. M, Nakamura M, Taguchi M, Fukuhara T, Imamura T, Kouyama T, Lee Y. J, Horinouchi T, Peralta J, Iwagami N, Hashimoto G. L, Takagi S, Ohtsuki S, Murakami S, Yamamoto Y, Ogohara K, Ando H, Sugiyama K, Ishii N, Abe T, Hirose C, Suzuki M, Hirata N, Young E. F, Ocampo A. C

      Earth Planets and Space70   2018

    • Topographical and Local Time Dependence of Large Stationary Gravity Waves Observed at the Cloud Top of Venus Peer-reviewed

      T. Kouyama, T. Imamura, M. Taguchi, T. Fukuhara, T. M. Sato, A. Yamazaki, M. Futaguchi, S. Murakami, G. L. Hashimoto, M. Ueno, N. Iwagami, S. Takagi, M. Takagi, K. Ogohara, H. Kashimura, T. Horinouchi, N. Sato, M. Yamada, Y. Yamamoto, S. Ohtsuki, K. Sugiyama, H. Ando, M. Takamura, T. Yamada, T. Satoh, M. Nakamura

      Geophysical Research Letters44 ( 24 ) 12 - 105   28 12 2017

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

      The existence of large stationary gravity waves was discovered during Akatsuki's first observation sequence in 2015. In this study, the further detection of large stationary gravity waves in brightness temperature images over a 1.5 year period is reported. The waves periodically appeared mostly above four specific highland regions in the low latitudes when these regions were in the local afternoon. The wave amplitudes attenuated after the wave locations passed beyond the evening terminator, and the locations of the waves tended to slowly drift eastward over their lifetimes. The appearances of stationary waves depend not only on surface topography but also on latitude and local time, suggesting that solar heating during the daytime and atmospheric structure affected by solar heating may control the excitation and propagation of stationary waves.

      DOI: 10.1002/2017GL075792

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    • Overview of Akatsuki data products: definition of data levels, method and accuracy of geometric correction Peer-reviewed

      Kazunori Ogohara, Masahiro Takagi, Shin ya Murakami, Takeshi Horinouchi, Manabu Yamada, Toru Kouyama, George L. Hashimoto, Takeshi Imamura, Yukio Yamamoto, Hiroki Kashimura, Naru Hirata, Naoki Sato, Atsushi Yamazaki, Takehiko Satoh, Naomoto Iwagami, Makoto Taguchi, Shigeto Watanabe, Takao M. Sato, Shoko Ohtsuki, Tetsuya Fukuhara, Masahiko Futaguchi, Takeshi Sakanoi, Shingo Kameda, Ko ichiro Sugiyama, Hiroki Ando, Yeon Joo Lee, Masato Nakamura, Makoto Suzuki, Chikako Hirose, Nobuaki Ishii, Takumi Abe

      Earth, Planets and Space69   1 12 2017

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

      © 2017, The Author(s). We provide an overview of data products from observations by the Japanese Venus Climate Orbiter, Akatsuki, and describe the definition and content of each data-processing level. Levels 1 and 2 consist of non-calibrated and calibrated radiance (or brightness temperature), respectively, as well as geometry information (e.g., illumination angles). Level 3 data are global-grid data in the regular longitude–latitude coordinate system, produced from the contents of Level 2. Non-negligible errors in navigational data and instrumental alignment can result in serious errors in the geometry calculations. Such errors cause mismapping of the data and lead to inconsistencies between radiances and illumination angles, along with errors in cloud-motion vectors. Thus, we carefully correct the boresight pointing of each camera by fitting an ellipse to the observed Venusian limb to provide improved longitude–latitude maps for Level 3 products, if possible. The accuracy of the pointing correction is also estimated statistically by simulating observed limb distributions. The results show that our algorithm successfully corrects instrumental pointing and will enable a variety of studies on the Venusian atmosphere using Akatsuki data.

      DOI: 10.1186/s40623-017-0749-5

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    • Ecliptic North-South Symmetry of Hydrogen Geocorona Peer-reviewed

      S. Kameda, S. Ikezawa, M. Sato, M. Kuwabara, N. Osada, G. Murakami, K. Yoshioka, I. Yoshikawa, M. Taguchi, R. Funase, S. Sugita, Y. Miyoshi, M. Fujimoto

      GEOPHYSICAL RESEARCH LETTERS44 ( 23 ) 11706 - 11712   12 2017

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

      The hydrogen exosphere constitutes the uppermost atmospheric layer of the Earth, and its shape may reflect the last stage of the atmospheric escape process. The distribution of hydrogen in the outer exosphere remains unobserved because outer geocoronal emissions are difficult to observe from within the exosphere. In this study, we used the Lyman Alpha Imaging Camera on board the Proximate Object Close Flyby with Optical Navigation spacecraft, located outside the exosphere, to obtain the first image of the entire geocorona that extends to more than 38 Earth radii. The observed emission intensity distribution can be reproduced using our analytical model that has three parameters: exobase temperature, exobase density, and solar radiation pressure, which implies that hot hydrogen production in the magnetized plasmasphere is not the dominant process shaping the outer hydrogen exosphere. However, the role of the magnetic effect in determining the total escape flux cannot be ruled out.

      DOI: 10.1002/2017GL075915

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    • Absolute calibration of brightness temperature of the Venus disk observed by the Longwave Infrared Camera onboard Akatsuki Peer-reviewed

      Tetsuya Fukuhara, Makoto Taguchi, Takeshi Imamura, Akane Hayashitani, Takeru Yamada, Masahiko Futaguchi, Toru Kouyama, Takao M. Sato, Mao Takamura, Naomoto Iwagami, Masato Nakamura, Makoto Suzuki, Munetaka Ueno, George L. Hashimoto, Mitsuteru Sato, Seiko Takagi, Atsushi Yamazaki, Manabu Yamada, Shin-ya Murakami, Yukio Yamamoto, Kazunori Ogohara, Hiroki Ando, Ko-ichiro Sugiyama, Hiroki Kashimura, Shoko Ohtsuki, Nobuaki Ishii, Takumi Abe, Takehiko Satoh, Chikako Hirose, Naru Hirata

      EARTH PLANETS AND SPACE69   10 2017

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

      The Venus Climate Orbiter Akatsuki arrived at Venus in December 2015, and the Longwave Infrared Camera (LIR) onboard the spacecraft started making observations. LIR has acquired more than 8000 images during the first two Venusian years since orbit insertion without any serious faults. However, brightness temperature derived from LIR images contained an unexpected bias that related not to natural phenomena but to a thermal condition of the instrument. The bias could be partially eliminated by keeping the power supply unit for LIR always active, while the residual bias was simply correlated with the baffle temperature. Therefore, deep-space images were acquired at different baffle temperatures on orbit, and a reference table for eliminating the bias from images was prepared. In the corrected images, the brightness temperature was similar to 230 K at the center of the Venus disk, where the effect of limb darkening is negligible. The result is independent of the baffle temperature and consistent with the results of previous studies. Later, a laboratory experiment with the proto model of LIR showed that when the germanium (Ge) lens was heated, its actual temperature was slightly higher than the temperature measured by a thermal sensor attached to the lens holder. The experiment confirmed that transitory baffle heating accounted for the background bias found in the brightness temperature observed by LIR.

      DOI: 10.1186/s40623-017-0727-y

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    • Earth and Moon Images by Thermal Infrared Imager TIR on Hayabusa2 and Its Implications to Observations of Asteroid Ryugu

      Okada, T, Fukuhara, T, Tanaka, S, Taguchi, M, Arai, T, Senshu, H, Ogawa, Y, Demura, H, Kitazato, K, Nakamura, R, Kouyama, T, Sekiguchi, T, Hasegawa, S, Matsunaga, T, Wada, T, Imamura, T, Takita, J, Sakatani, N, Horikawa, Y, Endo, K, Helbert, J, Mueller, T. G, Hagermann, A

      48th Lunar and Planetary Science Conference1964 ( 1818 )   3 2017

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    • IMAGING OBSERVATIONS OF THE HYDROGEN COMA OF COMET 67P/CHURYUMOV-GERASIMENKO IN 2015 SEPTEMBER BY THE PROCYON/LAICA Peer-reviewed

      Yoshiharu Shinnaka, Nicolas Fougere, Hideyo Kawakita, Shingo Kameda, Michael R. Combi, Shota Ikezawa, Ayana Seki, Masaki Kuwabara, Masaki Sato, Makoto Taguchi, Ichiro Yoshikawa

      ASTRONOMICAL JOURNAL153 ( 2 )   2 2017

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      Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

      The water production rate of a comet is one of the. fundamental parameters necessary. to understand cometary activity when a comet approaches the Sun within 2.5 au, because water is the most abundant icy material in the cometary nucleus. Wide-field imaging observations of the hydrogen Ly alpha emission in comet 67P/Churyumov-Gerasimenko were performed by the Lyman Alpha Imaging Camera (LAICA) on. board the 50 kg class micro spacecraft, the Proximate Object Close Flyby with Optical Navigation (PROCYON), on UT 2015 September 7.40, 12.37, and 13.17 (corresponding to 25.31, 30.28, and 31.08 days after the perihelion passage of the comet, respectively). We derive the water production rates, QH(2)O, of the comet from Lya images of the comet by using a 2D axi-symmetric Direct Simulation Monte-Carlo model of the atomic hydrogen coma; (1.46. +/- 0.47) x 10(28), (1.24. +/- 0.40) x10(28), and (1.30. +/- 0.42) x 10(28) molecules s(-1) on 7.40, 12.37, and 13.17 September, respectively. These values are comparable to the values from in situ measurements by the Rosetta instruments in the 2015 apparition and the ground-based and space observations during the past apparitions. The comet did not show significant secular change in average water production rates just after the perihelion passage for the apparitions from 1982 to 2015. We emphasize that the measurements of absolute QH(2)O based on the wide field of view (e. g., by the LAICA/PROCYON) are so important to judge the soundness of the coma models used to infer QH(2)O based on in situ measurements by spacecraft, like the Rosetta.

      DOI: 10.3847/1538-3881/153/2/76

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    • Large stationary gravity wave in the atmosphere of Venus Peer-reviewed

      Tetsuya Fukuhara, Masahiko Futaguchi, George L. Hashimoto, Takeshi Horinouchi, Takeshi Imamura, Naomoto Iwagaimi, Toru Kouyama, Shin-ya Murakami, Masato Nakamura, Kazunori Ogohara, Mitsuteru Sato, Takao M. Sato, Makoto Suzuki, Makoto Taguchi, Seiko Takagi, Munetaka Ueno, Shigeto Watanabe, Manabu Yamada, Atsushi Yamazaki

      NATURE GEOSCIENCE10 ( 2 ) 85 - +   2 2017

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      Authorship:Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:NATURE PUBLISHING GROUP  

      The planet Venus is covered by thick clouds of sulfuric acid that move westwards because the entire upper atmosphere rotates much faster than the planet itself. At the cloud tops, about 65 km in altitude, small-scale features are predominantly carried by the background wind at speeds of approximately 100 ms(-1). In contrast, planetary-scale atmospheric features have been observed to move slightly faster or slower than the background wind, a phenomenon that has been interpreted to reflect the propagation of planetary-scale waves. Here we report the detection of an interhemispheric bow-shaped structure stretching 10,000 km across at the cloud-top level of Venus in middle infrared and ultraviolet images from the Japanese orbiter Akatsuki. Over several days of observation, the bow-shaped structure remained relatively fixed in position above the highland on the slowly rotating surface, despite the background atmospheric super rotation. We suggest that the bow-shaped structure is the result of an atmospheric gravity wave generated in the lower atmosphere by mountain topography that then propagated upwards. Numerical simulations provide preliminary support for this interpretation, but the formation and propagation of a mountain gravity wave remain difficult to reconcile with assumed near-surface conditions on Venus. We suggest that winds in the deep atmosphere may be spatially or temporally more variable than previously thought.

      DOI: 10.1038/NGEO2873

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    • Thermal Infrared Imaging Experiments of C-Type Asteroid 162173 Ryugu on Hayabusa2 Peer-reviewed

      Okada T, Fukuhara T, Tanaka S, Taguchi M, Imamura T, Arai T, Senshu H, Ogawa Y, Demura H, Kitazato K, Nakamura R, Kouyama T, Sekiguchi T, Hasegawa S, Matsunaga T, Wada T, Takita J, Sakatani N, Horikawa Y, Endo K, Helbert J, Muller T. G, Hagermann A

      Space Science Reviews208 ( 1-4 ) 255 - 286   2017

    • FUJIN-2:Balloon Borne Telescope for Optical Observation of Planets Peer-reviewed

      Yasuhiro SHOJI, Makoto TAGUCHI, Toshihiko NAKANO, Atsunori MAEDA, Masataka IMAI, Yuya GOUDA, Makoto WATANABE, Yukihiro TAKAHASHI, Yuji SAKAMOTO, Kazuya YOSHIDA

      TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, Vol. 14 (2016) No. ists30, Oct. 2016, Pk_95-Pk_102   30 10 2016

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    • IR heterodyne spectrometer MILAHI for continuous monitoring observatory of Martian and Venusian atmospheres at Mt. Haleakala, Hawaii Peer-reviewed

      Hiromu Nakagawa, Shohei Aoki, Hideo Sagawa, Yasumasa Kasaba, Isao Murata, Guido Sonnabend, Manuela Sornig, Shoichi Okano, Jeffrey R. Kuhn, Joseph M. Ritter, Masato Kagitani, Takeshi Sakanoi, Makoto Taguchi, Kosuke Takami

      PLANETARY AND SPACE SCIENCE126   34 - 48   7 2016

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

      A new Mid-Infrared Laser Heterodyne Instrument (MILAHI) with &gt; 10(6) resolving power at 7-12 mu m was developed for continuous monitoring of planetary atmospheres by using dedicated ground-based telescopes for planetary science at Mt. Haleakala, Hawaii. Room-temperature-type quantum cascade lasers (QCLs) that cover wavelength ranges of 7.69-7.73, 9.54-9.59, and 10.28-10.33 mu m have been newly installed as local oscillators to allow observation of CO2, CH4, H2O2, H2O, and HDO. Modeling and predictions by radiative transfer code gave the following scientific capabilities and measurement sensitivities of the MILAHI. (1) Temperature profiles are achieved at altitudes of 65-90 km on Venus, and the ground surface to 30 km on Mars. (2) New wind profiles are provided at altitudes of 75-90 km on Venus, and 5-25 km on Mars. (3) Direct measurements of the mesospheric wind and temperature are obtained from the Doppler-shifted emission line at altitudes of 110 km on Venus and 75 km on Mars. (4) Detections of trace gases and isotopic ratios are performed without any ambiguity of the reproducing the terrestrial atmospheric absorptions in the observed wavelength range. A HDO measurement of twice the Vienna Standard Mean Ocean Water (VSMOW) can be obtained by 15-min integration, while H2O of 75 ppm is provided by 3.62-h integration. The detectability of the 100 ppb-CH4 on Mars corresponds to an integration time of 32 h. (C) 2016 Elsevier Ltd All rights reserved.

      DOI: 10.1016/j.pss.2016.04.002

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    • AKATSUKI returns to Venus Peer-reviewed

      Masato Nakamura, Takeshi Imamura, Nobuaki Ishii, Takumi Abe, Yasuhiro Kawakatsu, Chikako Hirose, Takehiko Satoh, Makoto Suzuki, Munetaka Ueno, Atsushi Yamazaki, Naomoto Iwagami, Shigeto Watanabe, Makoto Taguchi, Tetsuya Fukuhara, Yukihiro Takahashi, Manabu Yamada, Masataka Imai, Shoko Ohtsuki, Kazunori Uemizu, George L. Hashimoto, Masahiro Takagi, Yoshihisa Matsuda, Kazunori Ogohara, Naoki Sato, Yasumasa Kasaba, Toru Kouyama, Naru Hirata, Ryosuke Nakamura, Yukio Yamamoto, Takeshi Horinouchi, Masaru Yamamoto, Yoshi-Yuki Hayashi, Hiroki Kashimura, Ko-ichiro Sugiyama, Takeshi Sakanoi, Hiroki Ando, Shin-ya Murakami, Takao M. Sato, Seiko Takagi, Kensuke Nakajima, Javier Peralta, Yeon Joo Lee, Junichi Nakatsuka, Tsutomu Ichikawa, Kozaburo Inoue, Tomoaki Toda, Hiroyuki Toyota, Sumitaka Tachikawa, Shinichiro Narita, Tomoko Hayashiyama, Akiko Hasegawa, Yukio Kamata

      EARTH PLANETS AND SPACE68   75   5 2016

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

      AKATSUKI is the Japanese Venus Climate Orbiter that was designed to investigate the climate system of Venus. The orbiter was launched on May 21, 2010, and it reached Venus on December 7, 2010. Thrust was applied by the orbital maneuver engine in an attempt to put AKATSUKI into a westward equatorial orbit around Venus with a 30-h orbital period. However, this operation failed because of a malfunction in the propulsion system. After this failure, the spacecraft orbited the Sun for 5 years. On December 7, 2015, AKATSUKI once again approached Venus and the Venus orbit insertion was successful, whereby a westward equatorial orbit with apoapsis of similar to 440,000 km and orbital period of 14 days was initiated. Now that AKATSUKI's long journey to Venus has ended, it will provide scientific data on the Venusian climate system for two or more years. For the purpose of both decreasing the apoapsis altitude and avoiding a long eclipse during the orbit, a trim maneuver was performed at the first periapsis. The apoapsis altitude is now similar to 360,000 km with a periapsis altitude of 1000-8000 km, and the period is 10 days and 12 h. In this paper, we describe the details of the Venus orbit insertion-revenge 1 (VOI-R1) and the new orbit, the expected scientific information to be obtained at this orbit, and the Venus images captured by the onboard 1-mu m infrared camera, ultraviolet imager, and long-wave infrared camera 2 h after the successful initiation of the VOI-R1.

      DOI: 10.1186/s40623-016-0457-6

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    • The first Japan's planetary orbiter AKATSUKI and its scientific results

      Masato Nakamura, Nobuaki Ishii, Takeshi Imamura, Takehiko Satoh, Takumi Abe, Chikako Hirose, Atsushi Yamazaki, Junichi Nakatsuka, Tsutomu Ichikawa, Tomoaki Toda, Hiroyuki Toyoda, Sumitaka Tachikawa, Yukio Kamata, Makoto Suzuki, Takao M. Sato, Shin Ya Murakami, Yukio Yamamoto, Naomoto Iwagami, Makoto Taguchi, Tesuya Fukuhara, Shigeto Watanabe, Yukihiro Takahashi, Munetaka Ueno, Manabu Yamada, George L. Hashimoto, Naru Hirata, Toru Kouyama, Kazunori Ogohara, Hiroki Ando, Koichiro Sugiyama, Hiroki Kashimura, Shoko Ohtsuki

      Proceedings of the International Astronautical Congress, IAC   1 1 2016

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      Copyright © 2016 by the International Astronautical Federation (IAF). All rights reserved. Japan&#039;s Venus Climate Orbiter Akatsuki was proposed to ISAS (Institute of Space and Astronautical Science) in 2001 as an interplanetary mission. We made 5 cameras with narrow-band filters to image Venus at different wavelengths to track the cloud and minor components distribution at different heights to study the Venusian atmospheric dynamics in 3 dimension. It was launched on May 21st, 2010 and reached Venus on December 7th, 2010. With the thrust by the orbital maneuver engine, Akatsuki tried to go into the westward equatorial orbit around Venus with the 30 hours&#039; orbital period, however it failed by the malfunction of the propulsion system. Later the spacecraft has been orbiting the sun for 5 years. On December 7th, 2015 Akatsuki met Venus again after the orbit control and Akatsuki was put into the westward equatorial orbit whose apoapsis is about 0.44 million km and orbital period of 14 days. Its main target is to shed light on the mechanism of the fast atmospheric circulation of Venus. The systematic imaging sequence by Akatsuki is advantageous for detecting meteorological phenomena with various temporal and spatial scales. We have five photometric sensors as mission instruments for imaging, which are 1 m-infrared camera (IR1), 2 m-infrared camera (IR2), ultra-violet imager (UVI), long-wave infrared camera (LIR), and lightning and airglow camera (LAC). These photometers except LIR have changeable filters in the optics to image in certain wavelengths. Akatsuki&#039;s long elliptical orbit around Venus is suitable for obtaining cloud-tracked wind vectors over a wide area continuously from high altitudes. With the observation, the characterizations of the meridional circulation, mid-latitude jets, and various wave activities are anticipated. The technical issues of Venus orbit insertion in 2015 and the scientific new results will be given in this paper.

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    • Imaging-based observations of low-latitude auroras during 2001-2004 at Nayoro, Japan Peer-reviewed

      Hidehiko Suzuki, Haruka Chino, Yasuo Sano, Akira Kadokura, Mitsumu K. Ejiri, Makoto Taguchi

      EARTH PLANETS AND SPACE67   107   7 2015

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

      Color images of six low-latitude auroral events observed using color digital cameras at Nayoro (142.5 degrees E, 44.4 degrees N), Hokkaido, Japan, from 2001 to 2004, were analyzed to determine the events' locations and times of occurrence. Geographical azimuthal and elevation angles of the images' pixels were determined precisely by using the positions of the stars captured in the images. Horizontal regions covered by these auroral events were directly indicated by mapping the color images onto geographical maps and assuming that the emission layer's altitude is the lowest or highest value of a visible-level red aurora, as determined by the OI 630.0nm emission. The estimated geomagnetic latitudes and L values of these low-latitude auroral events were in the 39-50 degrees range and below L < 2.5, respectively. This investigation indicates that four of the six auroral events were the same as those that were reported previously based on high-sensitivity optical observations at other sites on Hokkaido (Rikubetsu and Moshiri). Although the previous study is lacking information about the maximal brightness level of the red auroral events, the present investigation suggests that these four low-latitude auroral events reached the visible level. In addition, two new events were reported in this study. The present work provides essential information such as the morphology and appearance of visible auroras, which are extremely rare in mid- or low-latitude regions.

      DOI: 10.1186/s40623-015-0278-z

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    • Visual orbit design for next mars exploration mission

      Ogura Satoshi, Yasuhiro Kawakatsu, Makoto Taguchi, Ayako Matsuoka

      Advances in the Astronautical Sciences153   583 - 596   2015

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      Publishing type:Research paper (international conference proceedings)  

      This study objectives are to devise orbit design methods and propose orbits fulfilling orbit constraints. The orbits were designed as follows: The orbiter's longitude of ascending node and argument of periapsis, in a Mars-Sun fixed coordinate system, are taken as design variables and the orbit constraint, proposed by a science group, is used as an evaluation function. A curved line that expresses a change history of orbiter's elements is draw in the plane. As a result, it is possible to find out rough initial values of longitude of ascending node and argument of periapsis suitable for the mission visually by moving the curved line, and also rough values of periapsis altitude, apoapsis altitude and inclination by choosing a form of orbit profile matching to the evaluation function.

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    • 火星大気散逸観測オービター計画の検討

          2015

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    • UV optical measurements of the Nozomi spacecraft interpreted with a two-component LIC-flow model (vol 491, pg 29, 2008) Peer-reviewed

      H. Nakagawa, M. Bzowski, A. Yamazaki, H. Fukunishi, S. Watanabe, Y. Takahashi, M. Taguchi, I. Yoshikawa, K. Shiomi, M. Nakamura

      ASTRONOMY & ASTROPHYSICS566   6 2014

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      Language:English   Publisher:EDP SCIENCES S A  

      DOI: 10.1051/0004-6361/20079241e

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    • 惑星大気散逸光学撮像観測のための迷光除去システムの基礎開発

      中川 広務, 山崎 敦, 塩谷 圭吾, 田口 真, 坂野井 健, 寺田 直樹, 関 華奈子, 松岡 彩子

      第14回宇宙科学シンポジウム 講演集   2014

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    • 国際宇宙ステーションからの超高層大気撮像観測ミッションISS-IMAPの現状

      齊藤 昭則, 秋谷祐亮, 穂積裕太, 山崎 敦, 阿部 琢美, 鈴木 睦, 村上豪, 坂野井 健, 吉川 一朗, 大塚 雄一, 藤原 均, 田口 真, 山本 衛, 中村 卓司, 江尻 省, 菊池 雅行, 河野 英昭, Huixin Liu, 石井 守, 久保田 実, 津川 卓也, 星野尾 一明, 坂野井 和代, IMAPワーキンググループ

      第14回宇宙科学シンポジウム 講演集   2014

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    • Return to venus of the Japanese venus climate orbiter AKATSUKI Peer-reviewed

      Masato Nakamura, Yasuhiro Kawakatsu, Chikako Hirose, Takeshi Imamura, Nobuaki Ishii, Takumi Abe, Atsushi Yamazaki, Manabu Yamada, Kazunori Ogohara, Kazunori Uemizu, Tetsuya Fukuhara, Shoko Ohtsuki, Takehiko Satoh, Makoto Suzuki, Munetaka Ueno, Junichi Nakatsuka, Naomoto Iwagami, Makoto Taguchi, Shigeto Watanabe, Yukihiro Takahashi, George L. Hashimoto, Hiroki Yamamoto

      Acta Astronautica93   384 - 389   2014

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      Japanese Venus Climate Orbiter/AKATSUKI was proposed in 2001 with strong support by international Venus science community and approved as an ISAS (The Institute of Space and Astronautical Science) mission soon after the proposal. The mission life we expected was more than two Earth years in Venus orbit. AKATSUKI was successfully launched at 06:58:22JST on May 21, 2010, by H-IIA F17. After the separation from H-IIA, the telemetry from AKATSUKI was normally detected by DSN Goldstone station (10:00JST) and the solar cell paddles' deployment was confirmed. After a successful cruise, the malfunction happened on the propulsion system during the Venus orbit insertion (VOI) on Dec. 7, 2010. The engine shut down before the planned reduction in speed to achieve. The spacecraft did not enter the Venus orbit but entered an orbit around the Sun with a period of 203 days. Most of the fuel still had remained, but the orbital maneuvering engine was found to be broken and unusable. However, we have found an alternate way of achieving orbit by using only the reaction control system (RSC). We had adopted the alternate way for orbital maneuver and three minor maneuvers in Nov. 2011 were successfully done so that AKATSUKI would meet Venus in 2015. We are considering several scenarios for VOI using only RCS. © 2013 IAA.

      DOI: 10.1016/j.actaastro.2013.07.027

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    • Inertia-gravity wave in the polar mesopause region inferred from successive images of a meteor train Peer-reviewed

      Hidehiko Suzuki, Takuji Nakamura, Sharon L. Vadas, Masaki Tsutsumi, Makoto Taguchi, Yasunori Fujiwara

      JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES118 ( 8 ) 3047 - 3052   4 2013

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      A fireball meteor with a visual magnitude over -6 followed by a persistent train was observed by two all-sky cameras for detecting the aurora and sodium airglow at Syowa Station (69.0 degrees S, 39.5 degrees E), Antarctica, on 7 June 2008. The orbit and other parameters of the fireball were estimated with an all-sky television camera for detecting the aurora. After the passage of this fireball, a circular train in the Na airglow was observed. This train expanded to a diameter of about 50 km in 9 min. Assuming that the fireball contained and emitted Na, we found this ring to span the altitudes of z = 76 to 87 km. The ring's mean motion was most likely caused by a large-scale, inertia-gravity wave with a vertical wavelength of similar to 16 km and an amplitude of similar to 30 m/s in the mesopause region.

      DOI: 10.1002/jgrd.50228

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    • Plasmaspheric filament: An isolated magnetic flux tube filled with dense plasmas Peer-reviewed

      Go Murakami, Ichiro Yoshikawa, Kazuo Yoshioka, Atsushi Yamazaki, Masato Kagitani, Makoto Taguchi, Masayuki Kikuchi, Shingo Kameda, Masato Nakamura

      Geophysical Research Letters40 ( 2 ) 250 - 254   28 1 2013

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      The Telescope of Extreme Ultraviolet (TEX) onboard Japan's lunar orbiter KAGUYA provided the first sequential images of the Earth's plasmasphere from the "side" (meridian) view. The TEX instrument obtained the global distribution of the terrestrial helium ions (He+) by detecting resonantly scattered emission at 30.4 nm. One of the most striking features of the plasmasphere found by TEX is an arc-shaped structure of enhanced brightness, which we call a "plasmaspheric filament". In the TEX image on 2 June 2008, the filament structure was clearly aligned to the dipole magnetic field line of L = 3.7 at 7.3 magnetic local time. Our analysis suggests that the filament represents an isolated flux tube filled with four times higher He + density than its neighbors. We found four events of plasmaspheric filament in the images obtained between March and June 2008, and in all four events, the geomagnetic activity was quite low. The plasmaspheric filament in the TEX image is the first evidence that a "finger" structure seen in the IMAGE-EUV image is the projection of an isolated flux tube. © 2013. American Geophysical Union. All Rights Reserved.

      DOI: 10.1002/grl.50124

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    • 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

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    • IMAP-WG国際宇宙ステーションからの地球超高層大気撮像観測ISS-IMAPミッションの初期成果

      齊藤昭則, 山崎 敦, 阿部琢美, 鈴木 睦, 坂野井 健, 吉川一朗, 大塚雄一, 藤原 均, 田口 真, 山本 衛, 中村卓司, 江尻 省, 菊池雅行, 河野英昭, Huixin Liu, 石井 守, 久保田 実, 津川卓也, 星野尾一明, 坂野井和代

      第13回宇宙科学シンポジウム   2013

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    • PERFORMANCE EVALUATION FOR POINTING CONTROL SYSTEM OF THE BALLOON-BORNE TELESCOPE Peer-reviewed

      T. Nakano, R. Fujimura, Y. Sakamoto, K. Yoshida, T. Kuwahara, Y. Shoji, M. Taguchi, M. Yamamoto, Y. Takahashi

      SPACE FOR OUR FUTURE146   381 - 391   2013

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      Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:UNIVELT INC  

      The balloon-borne telescope is a planetary observation method launching a telescope to the altitude of more than 30 km by a stratospheric balloon. To conduct the long duration observation, the flight gondola has to equip with a pointing control system in order to catch and keep the target star in the field of view of the telescope during the flight. This research aims to develop the high accuracy pointing control system and conduct the technology demonstration flight. The goal of the pointing control is set as 0.1 arcsec. This paper introduces the results of the ground test and simulation study to evaluate the performance of the pointing control system.

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    • Satellite-borne image sensors using an uncooled micro-bolometer array Peer-reviewed

        23 ( 1 ) 30 - 37   2013

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    • Double bursts inside a poleward-moving auroral form in the cusp Peer-reviewed

      S. Taguchi, K. Hosokawa, Y. Ogawa, T. Aoki, M. Taguchi

      JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS117   A12301   12 2012

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

      Poleward-moving auroral forms (PMAF), the ionospheric signatures of flux transfer events (FTEs), are intermittent phenomena observed in the cusp during negative interplanetary magnetic field intervals. Previous meridian scanning photometer-based observations showed that the distribution of the separation time between successive PMAFs is maximum at similar to 3.5 min. In this paper we present initial results from a new high-sensitivity all-sky imager, which was set up at Longyearbyen, Svalbard, Norway in October 2011. The 630.0-nm all-sky images taken with a time resolution of 4 s reveal that one of the PMAFs that occurred with such typical separation times on 29 December 2011 comprises two consecutive auroral bursts-the first occurring in the PMAF immediately after it was seen and the second, similar to 2 min later, following almost the same route. This observation provides evidence that one PMAF could reflect double FTEs-there is not always a one-to-one correspondence between FTEs and PMAFs. Reconnection on the dayside magnetopause would be modulated with a period of similar to 2 min during the course of transient reconnection. Citation: Taguchi, S., K. Hosokawa, Y. Ogawa, T. Aoki, and M. Taguchi (2012), Double bursts inside a poleward-moving auroral form in the cusp, J. Geophys. Res., 117, A12301, doi:10.1029/2012JA018150.

      DOI: 10.1029/2012JA018150

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    • Characteristic features in Venus' nightside cloud-top temperature obtained by Akatsuki/LIR Peer-reviewed

      Makoto Taguchi, Tetsuya Fukuhara, Masahiko Futaguchi, Mitsuteru Sato, Takeshi Imamura, Kazuaki Mitsuyama, Masato Nakamura, Munetaka Ueno, Makoto Suzuki, Naomoto Iwagami, George L. Hashimoto

      ICARUS219 ( 1 ) 502 - 504   5 2012

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      Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:ACADEMIC PRESS INC ELSEVIER SCIENCE  

      Mid-infrared images of almost the entire Venus nightside hemisphere obtained by the Longwave Infrared Camera (LIR) onboard Akatsuki on December 9 and 10, 2010 reveal that the brightness temperature of the cloud-top ranges from 237 K in the cold polar collars to 243 K in the equatorial region, significantly higher than the values obtained by Venera 15. Other characteristic features of the temperature distributions observed are zonal belt structures seen in the middle and low latitudes and patchy temperature structures or quasi-periodic streaks extending in a north-south direction in the northern middle latitudes and southern low latitudes. (c) 2012 Elsevier Inc. All rights reserved.

      DOI: 10.1016/j.icarus.2012.01.024

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    • Return to venus of the Japanese venus climate orbiter akatsuki

      Masato Nakamura, Yasuhiro Kawakatsu, Chikako Hirose, Takeshi Imamura, Nobuaki Ishii, Takumi Abe, Atsushi Yamazaki, Manabu Yamada, Kazunori Ogohara, Kazunori Uemizu, Tetsuya Fukuhara, Shoko Ohtsuki, Takehiko Satoh, Makoto Suzuki, Munetaka Ueno, Naomoto Iwagami, Makoto Taguchi, Shigeto Watanabe, Yukihiro Takahashi, George L. Hashimoto, Hiroki Yamamoto

      Proceedings of the International Astronautical Congress, IAC3   1727 - 1732   2012

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      Japanese Venus Climate Orbiter/AKATSUKI was proposed in 2001 with strong support by international Venus science community and approved as an ISAS (Institute of Space and Astronautical Science) mission soon after the proposal. The mission life we expected was more than two Earth years in Venus orbit. AKATSUKI was successfully launched at 06:58:22JST on May 21, 2010, by H-IIA F17. After the separation from H-IIA, the telemetry from AKATSUKI was normally detected by DSN Goldstone station (10:00JST) and the solar cell paddles' expansion was confirmed. The malfunction happened on the propulsion system during the Venus orbit insertion (VOI) on Dec 7, 2010. We failed to make the spacecraft become a Venus orbiter, and the spacecraft entered an orbit around the Sun with a period of 203 days. Most of the fuel still had remained, but the orbital maneuvering engine was found to be broken. We decided to use only the reaction control system (RCS) for orbital maneuver and three minor maneuvers in Nov 2011 were successfully done so that AKATSUKI will meet Venus in 2015. We are considering several scenarios for VOI using only RCS. Copyright © (2012) by the International Astronautical Federation.

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    • Early observation and future plan of the Ionosphere, Mesosphere, upper Atmosphere, and Plasmasphere mapping observation mission

      SAITO Akinori, YAMAZAKI Atsushi, SAKANOI Takeshi, YOSHIKAWA Ichiro, ABE Takumi, OTSUKA Yuichi, TAGUCHI Makoto, SUZUKI Makoto, KIKUCHI Masayuki, NAKAMURA Takuji, YAMAMOTO Mamoru, KAWANO Hideaki, LIU Huixin, ISHII Mamoru, TSUGAWA Takuya, SAKANOI Kazuyo, FUJIWARA Hitoshi, KUBOTA Minoru, EJIRI Mitsumu K, SAITO Akinori

      地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)132nd   ROMBUNNO.B005-18   2012

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    • The Pointing Control Method of Balloon-Borne Telescope Compensating the Motion of Flexible Base Peer-reviewed

      Nakano Toshihiko, Shoji Yasuhiro, Yamamoto Mutsumi, Hamamoto Ko, Nakamoto Jumpei, Imai Masataka, Sakamoto Yuji, Kuwahara Toshinori, Watanabe Makoto, Takahashi Yukihiro, Yoshida Kazuya, Taguchi Makoto, IEEE

      2012 Ieee/sice International Symposium on System Integration (Sii)   313 - 318   2012

    • Development of an MgF2 aspheric corrector for a VUV Schmidt camera Peer-reviewed

      TAGUCHI Makoto, NAKAMURA Tetsuya, ONO Junya

      JAXA research and development report11   1 - 11   2012

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      Authorship:Lead author, Corresponding author   Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Japan Aerospace Exploration Agency  

      Variations of electron density in the ionosphere accompanied by traveling ionospheric disturbances and plasma bubbles have been observed using ground-based airglow imaging and total electron content (TEC) measurements by a GPS network. However, these ground-based observations can detect only a portion of such wide-area phenomena, because the field-ofview from a ground station is limited. On the other hand, the intensity of the OI 135.6 nm night airglow emitted by radiative recombination processes is proportional to the square of the electron density in the F-region. Imaging the OI 135.6 nm emission using a geostationary satellite can reveal the entire distribution of these ionospheric phenomena. To detect variations in the weak OI 135.6 nm emission (~10 R) in middle and high latitudes with a spatial resolution of 100 km and a signal count of 1000 for an exposure time of 20 min, a sensitivity of 0.075 cts/s/R/pixel is required for a satellite-borne far ultraviolet (FUV) imager. For this reason, we adopted fast Schmidt optics for the FUV imager. The most technically challenging aspect of the design of such optics is the fabrication of an aspheric corrector using a vacuum ultraviolet transparent crystalline material such as MgF_2. In the present study, two different machining processes, magneto-rheological finishing and highaccuracy grinding, were compared for fine finishing the aspheric surfaces of the MgF_2 plates. The quality of the finished surfaces was evaluated by optical interferometry, and it was confirmed that a surface accuracy of 0.5λ PV (peak-to-valley) @ 135.6 nm was achieved with both processes. Since high-accuracy grinding was found to be more appropriate with regard to machining time, an aspheric surface with a 60% diameter (= 60 mm) and a maximum gradient and sag identical to those for the flight model corrector was manufactured using this process. The accuracy of the finished surface was evaluated to be 0.53λ PV. Simulations were then carried out to determine the overall optical performance of a corrector fabricated in this manner, and it was concluded that Schmidt optics using such a corrector can achieve the spatial resolution required for the FUV imager

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    • Short-period gravity waves and ripples in the South Pole mesosphere Peer-reviewed

      S. Suzuki, M. Tsutsumi, S. E. Palo, Y. Ebihara, M. Taguchi, M. Ejiri

      JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES116   D19109   10 2011

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      In this study, we determined the characteristics of mesospheric wave structures over South Pole Station (90 degrees S) derived from sodium airglow imaging observations. During the winter months of 2003 to 2005 (105 nights), we extracted a total of 768 wave events and separated them into two types (band-type gravity waves and ripples) according to their horizontal wavelengths. The distributions of the observed wave parameters, except for the horizontal propagation directions, were similar to those obtained by imaging observations at other latitudes. The observed gravity waves showed a preference for propagation toward 30-60 degrees E and 210-240 degrees E, whereas the ripples showed a preference for motion toward 90-120 degrees E and 300-330 degrees E. The gravity waves had a weak tendency of being observed in 0100-0700 UT, although the ripples did not show such a time dependence. We also investigated the characteristics of atmospheric instabilities from the alignment of the phase fronts of the observed ripples.

      DOI: 10.1029/2011JD015882

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    • ISS-IMAPミッションによって明らかになる超高層大気の姿

      斎藤昭則, 山崎敦, 阿部琢美, 鈴木睦, 坂野井健, 藤原均, 吉川一朗, 大塚雄一, 田口真, 山本衛, 中村卓司, 江尻省, 菊池雅行, 河野英昭, 石井守, 久保田実, 星野尾一明, 坂野井和代

      第25回大気圏シンポジウム   2011

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    • Image of the cold plasmas around the Earth observed by Telescope of Extreme Ultraviolet (TEX) onboard KAGUYA: Geoscience from the Moon Peer-reviewed

      Murakami, G, Yoshikawa, I, A. Yamazaki, K. Yoshioka, S. Kameda, W. Miyake, M. Taguchi, M. Kikuchi, M. Nakamura, T. Sakanoi, S. Okano

      Transactions of Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan8 ( 27 ) Tn_23 - Tn_28   2011

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      Language:English   Publishing type:Research paper (scientific journal)   Publisher:THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES  

      We have succeeded in imaging of the terrestrial plasmasphere by the Telescope of Extreme Ultraviolet (TEX) aboard Japan's lunar orbiter KAGUYA. The view afforded by the KAGUYA orbit encompasses the plasma distribution in a single exposure, enabling us to examine for the first time the globally-averaged properties of the plasmasphere from the "side" (meridian) perspective. This is the world first image of the plasmasphere from the moon.

      DOI: 10.2322/tastj.8.Tn_23

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    • LIR: Longwave Infrared Camera onboard the Venus orbiter Akatsuki Peer-reviewed

      Tetsuya Fukuhara, Makoto Taguchi, Takeshi Imamura, Masato Nakamura, Munetaka Ueno, Makoto Suzuki, Naomoto Iwagami, Mitsuteru Sato, Kazuaki Mitsuyama, George L. Hashimoto, Ryo Ohshima, Toru Kouyama, Hiroki Ando, Masahiko Futaguchi

      EARTH PLANETS AND SPACE63 ( 9 ) 1009 - 1018   2011

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

      The Longwave Infrared Camera (LIR) is one of a suite of cameras onboard the Venus orbiter Akatsuki. It will take images of thermal radiation in the wavelength range of 8-12 mu m emitted by the Venus cloud tops. The use of an uncooled micro-bolometer array as an infrared image sensor makes LIR a lightweight, small and low-power consumption instrument with a required noise equivalent temperature difference of 0.3 K. Temperature and horizontal wind fields at the cloud-top will be retrieved for both dayside and nightside with equal quality. This will provide key observations to understand the mechanism of super rotation and the thermal budget of the planet. LIR will also monitor variations of the polar dipole and collar which are characteristic thermal features in the Venusian atmosphere. Mechanisms of the upper-cloud formation will be investigated using sequences of close-up images. The morphology of the nightside upper cloud will be studied in detail for the first time.

      DOI: 10.5047/eps.2011.06.019

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    • Overview of Venus orbiter, Akatsuki Peer-reviewed

      M. Nakamura, T. Imamura, N. Ishii, T. Abe, T. Satoh, M. Suzuki, M. Ueno, A. Yamazaki, N. Iwagami, S. Watanabe, M. Taguchi, T. Fukuhara, Y. Takahashi, M. Yamada, N. Hoshino, S. Ohtsuki, K. Uemizu, G. L. Hashimoto, M. Takagi, Y. Matsuda, K. Ogohara, N. Sato, Y. Kasaba, T. Kouyama, N. Hirata, R. Nakamura, Y. Yamamoto, N. Okada, T. Horinouchi, M. Yamamoto, Y. Hayashi

      EARTH PLANETS AND SPACE63 ( 5 ) 443 - 457   2011

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

      The Akatsuki spacecraft of Japan was launched on May 21, 2010. The spacecraft planned to enter a Venus-encircling near-equatorial orbit in December 7, 2010; however, the Venus orbit insertion maneuver has failed, and at present the spacecraft is orbiting the Sun. There is a possibility of conducting an orbit insertion maneuver again several years later. The main goal of the mission is to understand the Venusian atmospheric dynamics and cloud physics, with the explorations of the ground surface and the interplanetary dust also being the themes. The angular motion of the spacecraft is roughly synchronized with the zonal flow near the cloud base for roughly 20 hours centered at the apoapsis. Seen from this portion of the orbit, cloud features below the spacecraft continue to be observed over 20 hours, and thus the precise determination of atmospheric motions is possible. The onboard science instruments sense multiple height levels of the atmosphere to model the three-dimensional structure and dynamics. The lower clouds, the lower atmosphere and the surface are imaged by utilizing near-infrared windows. The cloud top structure is mapped by using scattered ultraviolet radiation and thermal infrared radiation. Lightning discharge is searched for by high speed sampling of lightning flashes. Night airglow is observed at visible wavelengths. Radio occultation complements the imaging observations principally by determining the vertical temperature structure.

      DOI: 10.5047/eps.2011.02.009

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    • Variation in lunar sodium exosphere measured from lunar orbiter SELENE (Kaguya) Peer-reviewed

      M. Kagitani, M. Taguchi, A. Yamazaki, I. Yoshikawa, G. Murakami, K. Yoshioka, S. Kameda, S. Okano

      PLANETARY AND SPACE SCIENCE58 ( 12 ) 1660 - 1664   10 2010

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

      Resonant scattering of the lunar sodium exosphere was measured from the lunar orbiter SELENE (Kaguya) from December 2008 to June 2009. Variations in line-of-sight integrated intensity measured on the night-side hemisphere of the Moon could be described as a spherical symmetric distribution of the sodium exosphere with a temperature of 2400-6000 K. Average surface density of sodium atoms in February is well above that in the other months by about 30%. A clear variation in surface density related to the Moon&apos;s passage across the Earth&apos;s magnetotail could not be seen, although sodium density gradually decreased (by 20 +/- 8%) during periods from the first through the last quarter of two lunar cycles. These results suggest that the supra-thermal components of the sodium exosphere are not mainly produced by classical sputtering of solar wind. The variation in sodium density (which depends on lunar-phase angle) is possibly explained by the presence of an inhomogeneous source distribution of photon-stimulated desorption (PSD) on the surface. (c) 2010 Elsevier Ltd. All rights reserved.

      DOI: 10.1016/j.pss.2010.07.025

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    • Plasmaspheric EUV images seen from lunar orbit: Initial results of the extreme ultraviolet telescope on board the Kaguya spacecraft Peer-reviewed

      I. Yoshikawa, G. Murakami, G. Ogawa, K. Yoshioka, Y. Obana, M. Taguchi, A. Yamazaki, S. Kameda, M. Nakamura, M. Kikuchi, M. Kagitani, S. Okano, W. Miyake

      JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS115   4 2010

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

      The Telescope of Extreme Ultraviolet (TEX) aboard Japan's lunar orbiter Kaguya has succeeded in imaging of the plasmaspheric helium ions by detecting resonantly scattered emission at 30.4 nm. After the initial instrumental check was completed, TEX has been operated routinely, and EUV images from TEX have become available from the perspective of the lunar orbit. The view afforded by the Kaguya orbit encompasses the plasma (He+) distribution in a single exposure, enabling us to examine for the first time the globally averaged properties of the terrestrial plasmasphere from the "side" (meridian) perspective. In this paper we report the inward motion of the nightside plasmapause on 2 May 2008 as seen from this remote meridian view of the Earth. The southward turning of the IMF initiated the inward motion of the plasmapause, and the nightside plasmasphere shrunk at a rate of 0.2 Re/h. Simultaneous solar wind velocity measurements provide a possible explanation for the total radial displacement of the plasmasphere observed in the EUV images.

      DOI: 10.1029/2009JA014978

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    • Observation of the Near-Earth Plasmas by Telescope of Extreme Ultraviolet (TEX) Onboard SELENE: Science from the Moon Peer-reviewed

      Yoshikawa, I, Yamazaki, A, Murakami, G, Ezawa, F, Yoshioka, K, Kameda, S, Miyake, W, Taguchi, M, Kikuchi, M, Nakamura, M, Sakanoi, T, Okano, T

      Transactions of the Japan society for aeronautical and space sciences, space technology Japan7   27 - 32   2010

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      DOI: 10.2322/tstj.7.Tk_27

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    • Telescope of Extreme Ultraviolet boarded on KAGUYA: Science from the Moon Peer-reviewed

      Yoshikawa, I, Murakami, G, Ezawa, F, Yoshioka, K, Obana, Y, Taguchi, M, Yamazaki, A, Kameda, S, Nakamura, M, Kikuchi, M, Kagitani, M, Okano, S, Shiokawa, K, Miyake, W

      Advances in Geosciences19   109 - 121   2010

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      DOI: 10.1142/9789812838162_0009

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    • 国際宇宙ステーションJEM曝露部からの超高層大気撮像観測計画ISS-IMAP

      齊藤昭則, 阿部琢美, 山崎敦, 鈴木睦, 坂野井健, 藤原均, 吉川一朗, 大塚雄一, 田口真, 山本衛, 中村卓司, 菊池雅行, 江尻省, 河野英昭, 石井守, 久保田実, 星野尾一明, 坂野井和代

      第10回宇宙科学シンポジウム講演集   2010

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    • The balloon-borne telescope system for optical observation of planets Peer-reviewed

      Toshihiko Nakano, Yuji Sakamoto, Kazuya Yoshida, Toshinori Kuwahara, Yasuhiro Shoji, Makoto Taguchi, Mutumi Yamamoto, Yukihiro Takahashi

      2010 IEEE/SICE International Symposium on System Integration: SI International 2010 - The 3rd Symposium on System Integration, SII 2010, Proceedings   236 - 241   2010

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      Our team is carrying out the project of Planet observation with high precision using balloon-borne telescope. The first model, BBT-1 was equipped with a three stage pointing system and an optical system to observe the detailed structure of the atmospheric motion of Venus. The first flight test was conducted in 2009, and the performance of the system was verified. However, because of a trouble of onboard computer, the flight operation could not been finished as planned. The second model "BBT-2" is now being developed and the next flight test is planned in 2011.The BBT-2 has a bus system including FPGAs and CPU,and it is expected to be more stable than the BBT-1. ©2010 IEEE.

      DOI: 10.1109/SII.2010.5708331

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    • Highly Precise Pointing Control System on a Balloon-Borne Telescope for Optical Observations of Planets Peer-reviewed

      Shoji, Y, T. Onishi, S. Battazzo, T. Teraguchi, A. Yoshimura, Y. Sakamoto, Y. Takahashi, K. Yoshida, M. Taguchi

      Trans. JSASS Aerospace Tech. Japan8 ( ists27 ) Pm_15 - Pm_20   2010

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      A balloon borne telescope is one of the space observation methods by carrying a telescope to the stratosphere with a huge balloon in order to be free from the atmospheric influences on observations. The authors have been developing a balloon borne telescope system for optical observations of other planets in the solar system. The observation aimed to achieve finer images of the planets than those taken by ground telescopes, which required the balloon borne telescope to hold the target star with subarcsec precision during the exposure of the camera. To meet the requirement, the system is equipped three stage pointing system. This article introduces the overview of the flight campaign and the flight system, and reports the pointing performance verified in ground experiments.

      DOI: 10.2322/tastj.8.Pm_15

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    • Variations of OH rotational temperature over Syowa Station in the austral winter of 2008 Peer-reviewed

      Hidehiko Suzuki, Yoshihiro Tomikawa, Makoto Taguchi, Takuji Nakamura, Masaki Tsutsumi

      EARTH PLANETS AND SPACE62 ( 8 ) 655 - 661   2010

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      A grating spectrometer for hydroxyl (OH) airglow installed at Syowa Station (69 degrees S, 39.6 degrees E) by the 49th Japanese Antarctic Research Expedition (JARE49) has been in operation since late February, 2008. A dataset of 153 nights was acquired at this location in the austral winter season of 2008. This dataset shows variations in the rotational temperature over a range of temporal scales. The rotational temperature around the polar mesopause region is high in winter and decreases toward summer, which is a pattern similar to that observed at Davis Station, located at almost the same latitude as Syowa Station. A large temperature variation with a period of several days was observed in early May, 2008. Based on a comparison with a simultaneous dataset obtained by the SABER instrument onboard the TIMED satellite, it is inferred that this rotational temperature variation was due to the modulation of vertical motions around the mesopause.

      DOI: 10.5047/eps.2010.07.010

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    • First sequential images of the plasmasphere from the meridian perspective observed by KAGUYA Peer-reviewed

      Go Murakami, Ichiro Yoshikawa, Yuki Obana, Kazuo Yoshioka, Gentaro Ogawa, Atsushi Yamazaki, Masato Kagitani, Makoto Taguchi, Masayuki Kikuchi, Shingo Kameda, Masato Nakamura

      EARTH PLANETS AND SPACE62 ( 4 ) E9 - E12   2010

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      Our understanding of plasmaspheric dynamics has increased in recent years largely due to the information generated during the IMAGE-EUV mission. Even though this successful mission has ended, we have succeeded in imaging the terrestrial helium ions (He(+)) by the Telescope of Extreme Ultraviolet (TEX) aboard the Japanese lunar orbiter KAGUYA by detecting resonantly scattered emission at 30.4 nm. The view afforded by the KAGUYA orbit encompasses the plasma (He(+)) distribution in a single exposure, enabling us to examine for the first time the globally averaged properties of the plasmasphere from the "side" (meridian) perspective. The TEX instrument observed a medium-scale density structure in the dawnside plasmasphere during a quiet period (1-2 June 2008). The meridian shape of the structure clearly agreed with the dipole magnetic field line. The TEX instrument also observed the structure in the plasmasphere co-rotating with a duration of 26 h, which is consistent with results from a number of recent studies derived from the IMAGE-EUV mission. These results confirm that the TEX instrument successfully obtained the spatial distribution and temporal variation of the plasmasphere.

      DOI: 10.5047/eps.2010.02.006

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    • The increase in OH rotational temperature during an active aurora event Peer-reviewed

      H. Suzuki, M. Tsutsumi, T. Nakamura, M. Taguchi

      ANNALES GEOPHYSICAE28 ( 3 ) 705 - 710   2010

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

      OH rotational temperatures have been observed at the Syowa Station, Antarctica (69 degrees S, 39 degrees E), which is located in the middle of the auroral zone and has a high-sensitivity spectrometer for the spectral region of the OH 8-4 band. A dataset of 153 nights was acquired during the 2008 austral winter season. Of the 153 nights, the weather and aurora conditions were only suitable on 6 nights to study the relationship between auroral activity and OH airglow variation. Of these 6 nights, a significant increase in the rotational temperature and a decrease in the intensity related to an aurora activity were identified on the night of 27/28 March 2008, but no such variations were seen during the other nights. The horizontal magnetic field disturbance on the night of 27/28 March was the largest of that winter, while the cosmic radio noise absorption was also very strong. These facts indicate that, compared with the other nights, a large flux of high-energy auroral particles precipitated during the night. It is suggested that the observed variations in the OH rotational temperature and airglow intensity were caused by a lowering of the average airglow height as a result of OH depletion in the upper part of the layer where high-energy auroral particles can reach.

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    • Site testing at Dome Fuji for submillimeter and terahertz astronomy: 220 GHz atmospheric-transparency Peer-reviewed

      S. Ishii, M. Seta, N. Nakai, S. Nagai, N. Miyagawa, A. Yamauchi, H. Motoyama, M. Taguchi

      POLAR SCIENCE3 ( 4 ) 213 - 221   1 2010

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      Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

      We measured the 220 GHz atmospheric-transparency at the Dome Fuji station in Antarctica from 18 December 2006 to 14 January 2007 using a tipping radiometer. The mean optical depth at zenith was 0.045 +/- 0.007, and during 98% of this period we measured an optical depth of less than 0.06. These data indicate that the atmospheric-transparency in summer at Dome Fuji is comparable to that of well-known submillimeter astronomical sites such as the Atacama desert in Chile in their best seasons. (C) 2009 Elsevier B.V. and NIPR. All rights reserved.

      DOI: 10.1016/j.polar.2009.08.001

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    • A balloon-borne telescope developed for remote sensing of planets from the polar stratosphere Peer-reviewed

      Taguchi, M, Y. Shoji, Y. Sakamoto, Kazuya Yoshida, Y. Takahashi, T. Teraguchi, T. Ohnishi, S. Battazzo, T. Sato, N. Hoshino, T. Uno, A. Yoshimura

      JAXA-RR   1 2010

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    • Synoptic distribution of dayside aurora: Multiple-wavelength all-sky observation at Yellow River Station in Ny-Alesund, Svalbard Peer-reviewed

      Z. -J. Hu, H. Yang, D. Huang, T. Araki, N. Sato, M. Taguchi, E. Seran, H. Hu, R. Liu, B. Zhang, D. Han, Z. Chen, Q. Zhang, J. Liang, S. Liu

      JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS71 ( 8-9 ) 794 - 804   6 2009

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

      Observations acquired from three-wavelength (427.8, 557.7 and 630.0 nm) all-sky imagers (ASIs) at Yellow River Station (YRS) in Ny-Alesund, Svalbard, are used to examine the synoptic distribution of dayside aurora. The results demonstrate that the maximum emission regions (MERs) at each wavelength are all located in the postnoon sector, but have rather different magnetic local time (MLT) distributions from each other. The so-called 15 MLT "hot spot" is the overlapping region of the MERs at three wavelengths, and the prenoon "warm spot" is characterized uniquely by an increase of emissions at the 557.7 nm wavelength. The detailed dayside auroral spectra and morphology as a function of MLT are discussed. (C) 2009 Elsevier Ltd. All rights reserved.

      DOI: 10.1016/j.jastp.2009.02.010

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    • Observation of the lunar sodium exposure using UPI-TVIS onboard SELENE (Kaguya) Peer-reviewed

      M. Kagitani, M. Taguchi, A. Yamazaki, I. Yoshikawa, G. Murakami, K. Yoshioka, S. Kameda, F. Ezawa, T. Toyota, S. Okano

      Earth Planet. Space61 ( 1-5 )   2009

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    • 気球搭載望遠鏡による惑星圏観測

      田口真, 吉田和哉, 坂本祐二, 荘司泰弘, 金澤知明, 高橋幸弘, 星野直哉, 佐藤隆雄, 坂野井健, 宇野健

      第9回惑星圏研究会集録   2009

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    • ISS-IMAP 搭載可視分光撮像装置VISI による大気光観測計

      坂野井健, 山崎敦, 大塚雄一, 田口真, 阿部琢美, 武山芸英, 小淵保幸, 齊藤昭則, 江尻省, 中村卓司, 鈴木睦, 久保田実, 吉川一朗, 星野尾一明, 坂野井和代, 藤原均, 山本衛, 石井守, 陣英克, 河野英昭

      平成20年度大気圏シンポジウム集録   2009

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    • Latitudinal dependence of the solar wind density derived from remote sensing measurements using interplanetary Lyman alpha emission from 1999 to 2002 Peer-reviewed

      Hiromu Nakagawa, Hiroshi Fukunishi, Shigeto Watanabe, Yukihiro Takahashi, Makoto Taguchi, Rosine Lallement

      EARTH PLANETS AND SPACE61 ( 3 ) 373 - 382   2009

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

      The interplanetary Lyman a backscattered emission is an effective tool for remote sensing of the global structure of the solar wind proton flux. This paper reports an attempt to derive the latitudinal dependence of the solar wind density by combining the interplanetary Lyman alpha measurements of the Nozomi spacecraft for the period 1999-2002 with the solar wind speed data derived from interplanetary scintillation measurements, This approach successfully revealed the slow and dense solar wind over the poles during the period of the solar maximum. Data on the. polar solar wind density indicate a significant gyowth from the middle of 2000, and the polar values of solar wind density are close to those of the equatorial values as a result of the disappearance of the coronal hole. A marked density depletion occurred in the middle of 200 1, which can be ascribed to the development of fast winds from the polar coronal hole. To evaluate the remote sensing method, we considered solar wind density data from in Situ measurements obtained by the Ulysses spacecraft. We conclude that our method basically agrees with in situ measurements, although we found a significant (a factor of 2) difference between these in the middle of 2001.

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    • Fast spectrometer for ground-based observations of OH rotational temperature Peer-reviewed

      Suzuki, H, M. Taguchi, Y. Kanai, N. Takeyama

      Appl. Opt.48 ( 6 ) 1119 - 1127   1 2009

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    • First optical observation of the Moon&apos;s sodium exosphere from the lunar orbiter SELENE (Kaguya) Peer-reviewed

      M. Kagitani, M. Taguchi, A. Yamazaki, I. Yoshikawa, G. Murakami, K. Yoshioka, S. Kameda, F. Ezawa, T. Toyota, S. Okano

      EARTH PLANETS AND SPACE61 ( 8 ) 1025 - 1029   2009

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      The first successful observations of resonant scattering emission from the lunar sodium exosphere were made from the lunar orbiter SELENE (Kaguya) using TVIS instruments during the period 17-19 December, 2008. The emission intensity of the NaD-line decreased by 12 +/- 6%, with an average value of 5.4 kR (kilorayleighs) in this period, which was preceded, by I day, by enhancement of the solar proton flux associated with a corotating interaction region. The results suggest that solar wind particles foster the diffusion of sodium atoms or ions in the lunar regolith up to the surface and that the time scale of the diffusion is a few tens of hours. The declining activity of the Geminid meteor shower is also one possible explanation for the decreasing sodium exosphere.

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    • The Upper Atmosphere and Plasma Imager/the Telescope of Visible Light (UPI/TVIS) onboard the Kaguya spacecraft Peer-reviewed

      M. Taguchi, T. Sakanoi, S. Okano, M. Kagitani, M. Kikuchi, M. Ejiri, I. Yoshikawa, A. Yamazaki, G. Murakami, K. Yoshioka, S. Kameda, W. Miyake, M. Nakamura, K. Shiokawa

      EARTH PLANETS AND SPACE61 ( 12 ) XVII - XXIII   2009

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      Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:TERRA SCIENTIFIC PUBL CO  

      The Upper Atmosphere and Plasma Imager (UPI) was placed in a lunar orbit in order to Study both the Moon and Earth. The UPI consists of two telescopes: a Telescope of Extreme Ultraviolet (TEX) and a Telescope of Visible Light (TVIS), which are both mounted on a two-axis gimbals system. The TVIS is equipped with fast catadioptric optics and a high-sensitivity CCD to image swift aurora and dark airglow ill the terrestrial upper atmosphere. TVIS has a field-of-view equivalent to the Earth&apos;s disk as seen from the Moon. The spatial resolution is about 30 km x 70 km on the Earth&apos;s surface at auroral latitudes. The observation wavelengths can be changed by selecting different bandpass filters. Using the images of the northern and Southern auroral ovals taken by TVIS, the intensities and shapes of the conjugate auroras will be quantitatively compared. Using the an-low imaging, medium- and large-scale ionospheric disturbances will be Studied. In this paper, the instrumental design and performance of TVIS are presented.

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    • UV optical measurements of the Nozomi spacecraft interpreted with a two-component LIC-flow model Peer-reviewed

      H. Nakagawa, M. Bzowski, A. Yamazaki, H. Fukunishi, S. Watanabe, Y. Takahashi, M. Taguchi, I. Yoshikawa, K. Shiomi, M. Nakamura

      ASTRONOMY & ASTROPHYSICS491 ( 1 ) 29 - 41   11 2008

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      Language:English   Publishing type:Research paper (scientific journal)   Publisher:EDP SCIENCES S A  

      Aims. Following recent reports on spectroscopic observations by SWAN/SOHO suggesting that the flows of neutral interstellar helium and hydrogen in the inner heliosphere are slightly divergent, we tried to verify them on the basis of simultaneous photometric observations of heliospheric hydrogen and helium glows performed by a spacecraft located on an orbit between the Earth and Mars (which differs from the orbit of SWAN/SOHO). The observations were interpreted with the use of various independent models of interstellar hydrogen and helium in the inner heliosphere, evaluated over a mesh of parameters.
      Methods. The data might suggest that the upwind and downwind directions of interstellar H may differ by less than 180 degrees, which we interpret as due to a side shift of the secondary population of interstellar hydrogen, which might be due to a deformation of the outer heliosheath e.g. because of the action of interstellar magnetic field. The simulations we performed do not support the idea that the secondary population is significantly shifted to the side.
      Results. The upwind/downwind direction of interstellar hydrogen as derived from our observations agrees within the error bars with the upwind/downwind direction of interstellar helium and the error bars include both the upwind direction of interstellar helium, derived from in-situ observations of GAS/Ulysses, and the upwind direction of interstellar hydrogen, derived from observations of SWAN/SOHO.

      DOI: 10.1051/0004-6361:20079241

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    • Development of the Longwave Infrared Camera (LTR) onboard PLANET-C Peer-reviewed

      Tetsuya Fukuhara, Makoto Taguchi, Takeshi Imamura, Masato Nakamura, Naomoto Iwagami, Munetaka Ueno, Makoto Suzuki, George L. Hashimotod, Mitsuteru Sato, Atsushi Yamazaki, Ryoichi Kashikawa, Isamu Higashino, Kazuhide Noguchi

      INFRARED TECHNOLOGY AND APPLICATIONS XXXIV, PTS 1 AND 26940   2008

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      Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:SPIE-INT SOC OPTICAL ENGINEERING  

      The Longwave Infrared Camera (LIR), which mounts an uncooled micro-bolometer array (UMBA), is under development for the Japanese Venus orbiter mission, PLANET-C. LIR detects thermal emission from the top of the sulfur dioxide cloud in a wavelength region 8-12 mu m to map the cloud-top temperature which is typically as low as 230 K. The requirement for the noise equivalent temperature difference (NETD) is 0.3 K. Images of blackbody targets in room temperature (similar to 300 K) and low temperature (similar to 230 K) have been acquired in a vacuum environment using a prototype model of LIR, showing that the NETD of 0.2 K and 0.8 K are achieved in similar to 300 K and -230 K, respectively. We expect that the requirement of NETD &lt; 0.3 K for similar to 230 K targets will be achieved by averaging several tens of images which are acquired within a few minutes. The vibration test for the UMBA was also carried out and the result showed the UMBA survived without any pixel defects or malfunctions. The tolerance to high-energy protons was tested and verified using a commercial camera in which a same type of UMBA is mounted. Based on these results, a flight model is now being manufactured with minor modifications from the prototype.

      DOI: 10.1117/12.784932

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    • 気球搭載望遠鏡による金星観測

      田口 真, 吉田 和哉, 坂本 祐二, 荘司 泰弘, 高橋 幸弘, 坂野井 健

      平成20年度大気球シンポジウム集録   2008

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    • TOPS mission:science payload and operation plan

      坂野井健, 高橋幸弘, 菊池健太郎, 山崎敦, 岩上直幹, 田口真, TOPS WG

      2006年度惑星圏研究集会集録   2008

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    • Atmospheric gravity waves identified by ground-based observations of the intensity and rotational temperature of OH airglow Peer-reviewed

      Suzuki. H, K. Shiokawa, M. Tsutsumi, T. Nakamura, M Taguchi

      Polar Sci   2, 1-8   2008

    • Telescope of extreme ultraviolet (TEX) onboard SELENE: science from the Moon Peer-reviewed

      I. Yoshikawa, A. Yamazaki, G. Murakami, K. Yoshioka, S. Kameda, F. Ezawa, T. Toyota, W. Miyake, M. Taguchi, M. Kikuchi, M. Nakamura

      EARTH PLANETS AND SPACE60 ( 4 ) 407 - 416   2008

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      The Upper Atmosphere and Plasma Imager (UPI) is to be launched in 2007 and sent to the Moon. From the lunar orbit, two telescopes are to be directed towards the Earth. The Moon has no atmosphere, which results in there being no active emission near the spacecraft; consequently, we will have a high-quality image of the near-Earth environment. As the Moon orbits the Earth once a month, the Earth will also be observed from many different directions. This is called a "science from the Moon". The two telescopes are mounted on a two-axis gimbal system, the Telescope of Extreme ultraviolet (TEX) and Telescope of Visible light (TVIS). TEX detects the O II (83.4 nm) and He II (30.4 nm) emissions scattered by ionized oxygen and helium, respectively. The targets of extreme-ultraviolet (EUV) imaging are the polar ionosphere, the polar wind, and the plasmasphere and inner magnetosphere. The maximum spatial and time resolutions are 0.09 Re and 1 min, respectively.

      DOI: 10.1186/BF03352805

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    • Dynamic Modeling and Experimental Verification of the Pointing Technology in Balloon-Borne Telescope System for Optical Remote Sensing of Planets Peer-reviewed

      Sakamoto, Y, T. Kanazawa, Y. Shoji, Y. Takahashi, K. Yoshida, M. Taguchi

      ISTS Special Issue: Selected papers from the 26th International Symposium on Space Technology and Science, Transactions of the JSASS, Space Technology Japan7 ( 26 ) Pd_23 - Pd_28   1 2008

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      Language:English   Publishing type:Research paper (scientific journal)   Publisher:THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES  

      Tohoku University and Rikkyo University are carrying out the project of Venus observation with high precision using a balloon-borne telescope. In this paper, the outline of Balloon-Borne Telescope for the optical remote sensing of Venus is introduced, and the simulation model of three-stage control method is constructed. For this observation, the pointing technology with high precision to restrain the slight moving of image is necessary. The target precision is only 0.1 arc seconds. The dynamics and control model is defined firstly, and the model parameters are determined by the experimental verification. By developing the numerical simulation tool, the motion can be estimated in the simulator, and the control strategy can be more easily optimized compared to the gain adjustment only based on experiments.

      DOI: 10.2322/tstj.7.Pd_23

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    • Fluctuation of intensity and rotational temperature of OH airglow caused by acoustic gravity waves Peer-reviewed

      Suzuki, H, K. Shiokawa, M. Tsutsumi, T. Nakamura, M. Taguchi

      Polar Sci.2   1 - 8   1 1 2008

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    • Quasi-stationary auroral patches observed at the South Pole Station Peer-reviewed

      Y. Ebihara, Y. -M. Tanaka, S. Takasaki, A. T. Weatherwax, M. Taguchi

      JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS112 ( A1 )   1 2007

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

      We present quasi-stationary auroral patches (QSAPs) observed by an all-sky imager at the South Pole Station (-74.3 degrees CGLAT) on the dayside between similar to 0900 and similar to 1400 MLT. QSAPs appeared in a closed field line region where I(557.7 nm) &gt;&gt; I(630.0 nm) and each patch tends to preserve its form, luminosity, and location for up to several hours. The quasi-stationary nature of the QSAPs cannot be explained by the traditional role of the corotation electric field because the South Pole is located on the axis of Earth&apos;s rotation. The most plausible scenario is that a corotation electric potential, which dominates the convection potential, results in a trapping region of the magnetospheric cold plasmas. On the analogy of the formation of the plasmasphere, the trapping region would capture cold plasmas originated from the ionosphere and result in a locally enhanced plasma density (miniplasmasphere) that may lead to electron scattering through cyclotron wave-particle interactions. This circumstance may occur when the South Pole is located on a closed field line and the local electric potential is dominated by the corotation potential. QSAPs were also accompanied with periodic fluctuations in the Pc 5 range, which coincide closely with ground magnetic fluctuations. Assuming that the pulsation is associated with field line resonances, we could estimate the equatorial mass density of thermal plasmas, which gradually increased from 0.13 to 0.44 amu cm(-3). The increase in the thermal plasma density would support the hypothesis that a miniplasmasphere exists, though further investigation is necessary to confirm it.

      DOI: 10.1029/2006JA012087

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    • Planet-C: Venus Climate Orbiter mission of Japan Peer-reviewed

      Nakamura, M, Imamura, T, Ueno, M, Iwagami, N, Satoh, T, Watanabe, S, Taguchi, M, Takahashi, Y, Suzuki, M, Abe, T, Hashimoto, G. L, Sakanoi, T, Okano, S, Kasaba, Y, Yoshida, J, Yamada, M, Ishii, N, Yamada, T, Uemizu, K, Fukuhara, T, Oyama, K

      Planet. Space Sci.55   1831 - 1842   1 1 2007

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    • Longwave Infrared Camera onboard the Venus Climate Orbiter Peer-reviewed

      M. Taguchi, T. Fukuhara, T. Imamura, M. Nakamura, N. Iwagami, M. Ueno, M. Suzuki, G. L. Hashimoto, K. Mitsuyama

      ADVANCES IN SPACE RESEARCH40 ( 6 ) 861 - 868   2007

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      Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCI LTD  

      The Longwave Infrared Camera (LIR) onboard the first Japanese Venus mission, PLANET-C, or the Venus Climate Orbiter, operates in the middle infrared region with a single bandpass filter of 8-12 mu m, measuring thermal radiation emitted from the cloud tops of the Venusian atmosphere. A horizontal wind vector field at the cloud-top height will be retrieved by means of a cloud tracking method. In addition, absolute temperature will be determined with an accuracy of 3 K. Since solar irradiation scattered by the atmosphere is much weaker than the atmospheric thermal radiation, LIR can continuously monitor a hemispheric wind field independent of the local time of the apocenter throughout the mission life. Wind and temperature fields obtained by LIR will provide key parameters to solve climatological issues related to the Venusian atmosphere. The use of an uncooled micro-bolometer array (UMBA), which requires no cryogenic apparatus, as an image sensor contributes to the reduction of power consumption and the weight of the LIR imager. An instrumental field-of-view of 12 degrees is equal to the angle subtended by Venus when observed from a height of 9.5 Rv. The pixel field-of-view corresponds to a spatial resolution of 70 km viewed from the apocenter. A mechanical shutter functions not only as an optical shutter but also as a reference blackbody. The temperature stability of the sensor is especially important, because fluctuation of thermal radiation from the internal environment of the sensor itself causes background noise. Therefore, the temperature of the UMBA package is stabilized at 313 +/- 0.1 K with a feedback controlled Peltier cooler/heater, and a NETD of 0.3 K, which is required for this infrared imager, will be achieved. Flat field images are taken with the shutter closed several seconds before and after 1 s exposure for a Venus thermal image. After a Venus image is taken, the LIR imager takes a cold calibration image of deep space. This measurement sequence is repeated every two hours when the spacecraft is orbiting at apocenter. Image data are transmitted down to the Earth after onboard calibration and data compression by common digital electronics. (c) 2007 COSPAR. Published by Elsevier Ltd. All rights reserved.

      DOI: 10.1016/j.asr.2007.05.085

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    • Development of airglow temperature photometers with cooled-CCD detectors Peer-reviewed

      K. Shiokawa, Y. Otsuka, S. Suzuki, T. Katoh, Y. Katohl, M. Satoh, T. Ogawa, H. Takahashi, D. Gobbli, T. Nakamura, B. P. Williams, C.-Y. She, M. Taguchi, T. Shimomai

      EARTH PLANETS AND SPACE59 ( 6 ) 585 - 599   2007

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      We have developed three airglow temperature photometers with cooled-CCD detectors. The photometers measure rotational temperatures using the airglow emissions of OH and 02 near the mesopause region (altitude: 80-100 km). The photometers also measure six other airglow and auroral lines at wavelengths of 55.7, 630.0, 777.4, 589.3, 427.8, and 486.1 nm. The CCD detectors are used to distinguish the emission lines in these airglow bands, similarly to those used by the Spectral Airglow Temperature Imagers (SATI). In this paper, we describe the configuration of the photometers, their calibration, the data processing to extract rotational temperatures and emission intensities from the measured airglow spectra, as well as the initial deployment at Platteville, Colorado (40.2 degrees N, 255 degrees E), when their observations were compared with the concurrent and nearly collocated observations by a sodium lidar. We obtain a good correlation and some systematic difference of temperatures from the photometers and the lidar, and discuss possible causes of the temperature difference.

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    • Balloon-Borne Telescope System for Optical Remote Sensing of Planetary Atmospheres and Plasmas Peer-reviewed

      Taguchi, M, K.Yohida, H.Nakanishi, Y.Shoji, K.Kawasaki, J.Shimasaki, Y.Takahashi, J.Yoshida, D.Tamura, T.Sakanoi

      Adv. Geosci.7   169 - 179   7 2006

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    • Advances in Polar Upper Atmosphere Research: Foreword Peer-reviewed

      Kadokura A, Ono T, Aso T, Ogawa T, Sato N, Yamagishi H, Makita K, Miyaoka H, Murayama Y, Taguchi M, Takahama N

      Advances in Polar Upper Atmosphere Research ( 20 )   2006

    • Mercury Sodium Atmosphere Spectral Imager (MSASI) Peer-reviewed

      Nozawa, H, I. Yoshikawa, S. Kameda, H. Misawa, S. Okano, M. Taguchi, A. Yamazaki, Y. Kasaba, K. Takamizawa, O. Korablev

      JAXA Research and Development Report   JAXA-RR-05-007E   2005

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    • Lyman alpha imaging of solar activity on the interplanetary hydrogen screen for space weather forecasting Peer-reviewed

      Y. Okazaki, H. Fukunishi, Y. Takahashi, M. Taguchi, S. Watanabe

      Journal of Geophysical Research: Space Physics110 ( 3 )   2005

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

      Interplanetary hydrogen atoms that penetrate into the heliosphere are illuminated by enhanced hydrogen Lyman alpha emission from solar active regions. Using the data obtained by the Solar Wind Anisotropies (SWAN) instrument on board the Solar and Heliospheric Observatory (SOHO), Bertaux et al. (2000) proposed a new method for earlier detection and monitoring of solar active regions on the far-side hemisphere. However, a quantitative relationship between the sky map of interplanetary Lyman alpha intensity and the enhanced emission from a solar active region was not discussed. Here, we analyze the interplanetary Lyman alpha intensity data obtained by the Ultraviolet Imaging Spectrometer (UVS) on board the Nozomi spacecraft. We develop a method to map the distribution of interplanetary Lyman alpha intensity into the Carrington coordinate system by assuming an interplanetary hydrogen screen at the location of maximum volume emission rate. Analysis period is from January 2000 to March 2000 near solar maximum. The solar activity during this analysis period is much higher as compared with the case study by Bertaux et al. (2000). The sky map of the Lyman alpha emission obtained by the UVS is shown to exhibit a high correlation with the solar extreme ultraviolet (EUV) intensity map obtained by the EUV Imaging Telescope (EIT) on board the SOHO satellite. The highest value of two-dimensional correlation coefficient is 0.80. An observed change in the periodicity of interplanetary Lyman alpha intensity is in good agreement with the growth of an active region on the Sun. It has been also confirmed that the far-side observations of UVS detected the growth of an active region in advance. This case study demonstrates that the location and intensity variation of activity on the far side of the Sun can be detected by far-side measurements of interplanetary Lyman alpha emission intensity. It is thus concluded that the developed method contributes to space weather forecasting on a scale of 2 weeks. Copyright 2005 by the American Geophysical Union.

      DOI: 10.1029/2004JA010828

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    • Auroral O+ 732/733 nm emission and its relation to ion upflow Peer-reviewed

      Koizumi, N, S. Okano, T. Sakanoi, M. Taguchi, T. Aso

      Adv. Polar Upper Atmos. Res.18   96 - 104   1 1 2004

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    • A new all-sky optics for aurora and airglow imaging Peer-reviewed

      Taguchi, M. M. Ejiri, K. Tomimatsu

      Adv. Polar Upper Atmos. Res.18   140 - 148   1 1 2004

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    • Solar cycle dependence of interplanetary Lyman α emission and solar wind anisotropics derived from NOZOMI/UVS and SOHO/SWAN observations Peer-reviewed

      Hiromu Nakagawa, Hiroshi Fukunishi, Yukihiro Takahashi, Shigeto Watanabe, Makoto Taguchi, Jean-Loup Bertaux, Rosine Lallement, Eric Quémerais

      Journal of Geophysical Research: Space Physics108 ( 10 ) 8035   2003

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

      We have investigated the distributions of neutral interplanetary hydrogen Lyman a emission and their solar cycle dependence from observations with the ultraviolet imaging spectrometer (UVS) onboard the NOZOMI spacecraft and the solar wind anisotropy instrument (SWAN) onboard the solar and heliospheric observatory (SOHO) spacecraft. The SOHO/SWAN observation covers the period from the solar minimum in 1996 to the solar maximum in 2001, while the NOZOMI/UVS observation covers the period of 1999-2001 near the solar maximum. The most distinct feature of the full sky Lyman α intensity maps near the solar maximum in 2000 is a structure with a single bright region extending across the ecliptic plane on the upwind side of the interstellar wind. This structure is entirely different from the structure observed by SWAN at the solar minimum in 1996, which shows an intensity depression called a "groove" and bright lobes above and below the groove centered near the ecliptic plane. From the fitting of model calculations to the observational data, it is confirmed that the latitudinal distribution of the ionization rate of the interplanetary hydrogen due to the charge exchange with solar wind protons becomes isotropic toward the solar maximum. However, an important result is that the condition for producing anisotropic ionization rate due to the slow, high-density solar wind around the equator exists by October 1999, although the theoretical model predicts isotropic ionization rate throughout 1999. Copyright 2003 by the American Geophysical Union.

      DOI: 10.1029/2003JA009882

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    • New auroral spectrometer using an aousto-optic tunable filter Peer-reviewed

      Shiokawa, K, Y. Katoh, M. Satoh, T. Ogawa, M. Taguchi, H. Yamagishi

      Adv. Polar Upper Atmos. Res.16   146 - 156   1 1 2002

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    • A new meridian imaging spectrograph for the auroral spectroscopy Peer-reviewed

      Taguchi, M, S. Okano, T. Sakanoi, N. Koizumi, T. Aso, M. Ejiri

      Adv. Polar Upper Atmos. Res.16   99 - 110   1 1 2002

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    • Simultaneous Observation of South Pole All-Sky Monochromatic Imager and SuperDARN - Initial Result of 1999 Campaign

      Sato, N, H. Yamagishi, A. S. Yukimatu, M. Watanabe, M. Ejiri, M. Okada, M. Taguchi, S. Okano, SuperDARN PIs

      Proc. SuperDARN 2000 workshop   2000

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    • Lunar albedo at hydrogen Lyman alpha by the NOZOMI/UVS Peer-reviewed

      M Taguchi, G Funabashi, S Watanabe, Y Takahashi, H Fukunishi

      EARTH PLANETS AND SPACE52 ( 9 ) 645 - 647   2000

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      Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:TERRA SCIENTIFIC PUBL CO  

      The geometric albedo of the Moon at the wavelength of hydrogen Lyman alpha (HLy alpha 121.6 nm) was derived from an imaging observation by the ultraviolet imaging spectrometer (UVS) during the lunar encounter of the NOZOMI spacecraft. The solar HLy alpha irradiance data measured by the UARS/SOLSTICE at the time of UVS observation were adopted. We obtained an average geometric albedo of 5.2 +/- 0.9% for the sunlit region where the WS observed. Our result agrees with the geometric albedos obtained from the observations by Apollo 17 and Astro-2/HUT, though the observation geometry and area are completely different from each other. There exists a significant difference of the albedos from place to place in the observed lunar surface ranging from 2.3 +/- 1.1% to 6.0 +/- 1.0%. It is noted that the observed contrast at the FUV wavelength is positive to that seen in the visible region.

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    • Ultraviolet imaging spectrometer (UVS) experiment on board the NOZOMI spacecraft: Instrumentation and initial results Peer-reviewed

      M Taguchi, H Fukunishi, S Watanabe, S Okano, Y Takahashi, TD Kawahara

      EARTH PLANETS AND SPACE52 ( 1 ) 49 - 60   2000

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      Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:TERRA SCIENTIFIC PUBL CO  

      An ultraviolet imaging spectrometer (UVS) on board the PLANET-B (NOZOMI) spacecraft has been developed. The UVS instrument consists of a grating spectrometer (UVS-G), an absorption cell photometer (UVS-P) and an electronics unit (UVS-E). The UVS-G features a flat-field type spectrometer measuring emissions in the FUV and MUV range between 110 nm and 310 nm with a spectral resolution of 2-3 nm. The UVS-P is a photometer separately detecting hydrogen (H) and deuterium (D) Lyman alpha emissions by the absorption cell technique. They take images using the spin and orbital motion of the spacecraft. The major scientific objectives of the UVS experiment at Mars and the characteristics of the UVS are described. The MUV spectra of geocoronal and interplanetary Lyman alpha emissions and lunar images taken at wavelength of hydrogen Lyman alpha and the background at 170 nm are presented as representative examples of the UVS observations during the Earth orbiting phase and the Mars transfer phase.

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    • Coordinated observations of the mesopause region with radar and optical techniques Peer-reviewed

      T Tsuda, T Nakamura, A Nomura, TD Kawahara, C Nagasawa, M Abo, S Okano, M Taguchi, M Ejiri

      ADVANCES IN REMOTE SENSING OF THE ATMOSPHERE FROM SPACE AND FROM THE GROUND26 ( 6 ) 907 - 916   2000

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      Language:English   Publishing type:Research paper (scientific journal)   Publisher:PERGAMON PRESS LTD  

      This paper reports the development of coordinated observations carried out with the use of the MU radar (middle and upper atmosphere radar) and optical measurement: techniques in Shigaraki. Since the start of the MU radar operation, mesosphere wind and turbulence were studied using mesospheric turbulence echo in the daytime. More recently, meteor echoes have been used to observe wind and temperature around the mesopause, during day and night, Comparative observations with the MU radar meteor mode and sodium lidars were used to study gravity waves and variation of sodium layers. Airglow observations were also carried out as a campaign basis, with which small scale and large scale gravity waves have been studied. We have also developed two CCD imagers to observe airglow images at the MU radar site for long term observations with the radar. Now Skigaraki has become an integrated optical/radar site ready to contribute to the PSMOS (Planetary Scale Mesopause Observing System) project being carried out between 1998-2002, (C) 2000 COSPAR. Published by Elsevier Science Ltd.

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    • Mars ultraviolet imaging spectrometer experiment on the PLANET-B mission Peer-reviewed

      H Fukunishi, S Watanabe, M Taguchi, S Okano, A Takahashi

      MOON AND MARS23 ( 11 ) 1903 - 1906   1999

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      Language:English   Publishing type:Research paper (scientific journal)   Publisher:PERGAMON PRESS LTD  

      An ultraviolet imaging spectrometer (UVS) has been developed for the PLANET-B spacecraft. The WS instrument is composed of a grating spectrometer (UVS-G) and a D/H absorption cell photometer (UVS-P). The UVS-G is a flat-field type spectrometer measuring optical emissions in the FUV and MUV range between 115 nm and 310 nm with a spectral resolution of 2 - 3 nm. The WS-P is a. photometer detecting hydrogen (H) and deuterium (D) Lyman alpha emissions separately by an absorption cell technique. Scientific targets of the UVS experiment are the investigation of (1) hydrogen and oxygen coronas around Mars, (2) the D/H ratio in the upper atmosphere, (3) dayglow, (4) aurora and nightglow, (5) dust, clouds and ozone, and (6) the surface composition of Phobos and Deimos. (C) 1999 COSPAR. Published by Elsevier Science Ltd.

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    • Japanese research project on Arctic and Antarctic observations of the middle atmosphere Peer-reviewed

      M Ejiri, T Aso, M Okada, M Tsutsumi, M Taguchi, N Sato, S Okano

      ANTARCTIC AND ARCTIC MIDDLE ATMOSPHERES: THEIR DIFFERENCES AND SIMILARITIES24 ( 12 ) 1689 - 1692   1999

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      Language:English   Publishing type:Research paper (scientific journal)   Publisher:PERGAMON PRESS LTD  

      An all-sky optical imager is in routine observation at the South Pole. Monochromatic images of aurora and air glow at N-2(+) 427.8nm, OI 557.7nm, OI 630nm and OH 730nm are supplying significant information on the magnetospheric process in the polar cap and cusp/cleft region along with atmospheric wave signature at this particular point. Super-DARN radars in Antarctica make observations over the South Pole.
      At Syowa Station, Antarctica, a multi-instrumental observation project is now being implemented for the study of the polar upper atmosphere from the mesosphere to the thermosphere, where complex physical and chemical processes take place making the region very attractive for scientific research. Two HF radars, which are part of SuperDARN radars, have been already installed and started observations. By the end of 1999, all-sky imagers, photo meters, a Na temperature Lidar, an MF radar and a Fabry-Perot interferometer will be introduced and start collecting various physical parameters on a routine basis.
      In the Arctic region, we are planning to deploy coordinated ground-based observations with optical, radio and radar sensing of the polar middle and upper atmosphere in conjunction with EISCAT radars. Scientific goals are versatile to shed light on the tangled coupling processes in response to magnetospheric disturbances from above and bi-lateral interactions with high-density lower atmospheric layers. These are outlined in this paper. (C) 1999 COSPAR. Published by Elsevier Science Ltd.

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    • Imaging observations of conjugate auroras from a lunar orbiter

      Taguchi, M, M. Ejiri, S. Okano, T. D. Kawahara, M. Okada, M. Nakamura

      Proc. NIPR Symp. Upper Atmos. Phys.12   175 - 176   1998

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    • All sky imager observation of aurora and airglow at South Pole : System design and the initial test results

      Ejiri, M, S. Okano, M. Okada, M.Taguchi, S. Takeshita

      Proc. NIPR Symp. Upper Atmos. Phys.11   159 - 162   1998

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    • System design and initial results of all sky imager at South Pole Peer-reviewed

      Okada, M, M. Ejiri, S. Okano, M. Taguchi, S. Takeshita

      Nankyoku Shiryo41   613 - 630   1 1 1997

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    • Ground-based remote sensing of atmospheric O-3, N2O, HNO3 and CH4 with a tunable diode laser heterodyne spectrometer at Syowa station, Antarctica Peer-reviewed

      M Koide, M Taguchi, H Fukumishi, S Okano

      OPTICAL SPECTROSCOPIC TECHNIQUES AND INSTRUMENTATION FOR ATMOSPHERIC AND SPACE RESEARCH II2830   41 - 51   1996

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      Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:SPIE - INT SOC OPTICAL ENGINEERING  

      Using the third version of tunable diode laser heterodyne spectrometers developed by the Tohoku university optical group, infrared absorption spectra of atmospheric O-3, N2O, CH4 and HNO3 were observed at Syowa station (69.0 degrees 8, 39.6 degrees E) from August 1994 to January 1995. This portable spectrometer has an ultra high spectral resolution of 0.0013 cm(-1) and a signal-to-noise ratio of 500 for 10-min scan time. From ozone absorption spectra obtained in early spring, the height profiles of ozone concentration up to 30 km were retrieved at intervals of ten minutes. These profiles showed extremely low ozone concentration in the altitude range of 15-20 km, which is a typical feature of the antarctic ozone hole. Furthermore, these profiles demonstrated the existence of rapid variations of ozone concentration in the altitude range of 20-30 km. From the potential vorticity analysis using the objective analysis data provided by the Japanese meteorological agency, it was concluded that these variations were caused by a passage of westward traveling waves produced at the polar vortex boundary.

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    • Studies on Infrared Remote Sensing of Stratospheric Ozone and Minor Constituents by the Laser Heterodyne Spectroscopy

      Makoto Taguchi

          8 3 1995

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    • Ground‐based remote sensing of methane height profiles with a tunable diode laser heterodyne spectrometer Peer-reviewed

      M. Koide, M. Taguchi, H. Fukunishi, S. Okano

      Geophysical Research Letters22 ( 4 ) 401 - 404   1995

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      Height distributions of methane in the troposphere and stratosphere were derived from high resolution absorption spectra observed with a ground‐based tunable diode laser heterodyne spectrometer. The center wavenumber of the measured methane absorption line is 1223.1561 cm−1. In the retrieval of methane height profiles, a volume mixing ratio of methane was assumed to have a constant value in the troposphere and to decrease with a constant rate in the stratosphere. The tropospheric mixing ratio and the decreasing rate in stratosphere were derived to be 1.7±0.1 ppmv and −0.06 ppmv/km, respectively, for measurements at Tsukuba (36.0°N, 140.1°E) on December 17 and 20, 1991. © 1995 by the Chinese Geophysical Society

      DOI: 10.1029/95GL00051

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    • Derivation of total ozone amounts over Japan from NOAA/TOVS data Peer-reviewed

      Takahashi, S, M. Taguchi, S. Okano, H. Fukunishi, H. Kawamura

      J. Meteorol. Soc. Japan70   919 - 928   1 1 1992

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    • Comparison of ozone profiles from ground‐based laser heterodyne spectrometer and ozonesonde measurements Peer-reviewed

      M. Taguchi, S. Okano, H. Fukunishi, Y. Sasano

      Geophysical Research Letters17 ( 13 ) 2349 - 2352   1990

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      To evaluate the accuracy of the vertical profiles and total column densities obtained by a ground‐based laser heterodyne spectrometer, four ozonesonde measurements were performed at Sendai, Japan in November 28–December 2, 1989. The altitudes, widths and maximum values of the peaks in the ozone vertical distributions obtained by the laser heterodyne observations agreed well with those obtained by the ozonesondes, though the fine structures in the ozone distributions can not be resolved by this remote sensing method. The total column densities and their temporal variation obtained by the laser heterodyne observations were also consistent with the ozonesonde data and the Dobson spectrophotometer data at Sapporo and Tateno. Copyright 1990 by the American Geophysical Union.

      DOI: 10.1029/GL017i013p02349

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    • Laser heterodyne spectrometer using a liquid nitrogen cooled tunable diode laser for remote measurements of atmospheric O3 and N2O Peer-reviewed

      Fukunishi, H, S. Okano, M. Taguchi, T. Ohnuma

      Appl. Opt.29   2722 - 2728   1 1 1990

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    • Remote sensing of vertical profiles of atmospheric ozone and nitrous oxide with a tunable diode laser heterodyne spectromter Peer-reviewed

      Taguchi, M, S. Okano, H. Fukunishi

      J. Meteorol. Soc. Japan68   79 - 93   1 1 1990

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    • Stratospheric ozone measurements with a tunable diode laser heterodyne spectrometer Peer-reviewed

      Okano, S, M. Taguchi, H. Fukunishi

      Geophys. Res. Lett.16   551 - 554   1 1 1989

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    Misc.

    • Dynamics of the polar mesopause region inferred by the long-term OH airglow observation at Syowa Station, Antarctic

      石井智士, 鈴木秀彦, 田中良昌, 堤雅基, 堤雅基, 田口真, 江尻省, 江尻省, 西山尚典, 西山尚典, 門倉昭

      地球電磁気・地球惑星圏学会総会及び講演会(Web)152nd   2022

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    • Relationship between the time scale of OH airglow enhancements detected at the Syowa Station and the variations of the background atmosphere.

      石井智士, 鈴木秀彦, 堤雅基, 堤雅基, 田口真, 江尻省, 江尻省, 西山尚典, 西山尚典, 門倉昭, 門倉昭, 門倉昭

      日本地球惑星科学連合大会予稿集(Web)2022   2022

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    • 一番星へ行こう!日本の金星探査機の挑戦 その48 〜金星の未知紫外線吸収物質を気球搭載光学望遠鏡FUJINで狙う〜

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      日本惑星科学会誌遊星人30 ( 4 ) 173 - 177   12 2021

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      Language:Japanese   Publishing type:Rapid communication, short report, research note, etc. (scientific journal)  

      DOI: 10.14909/yuseijin.30.4_173

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    • Relationship between energetic particle precipitations and an intensity of OH airglow over Syowa Station.

      石井智士, 鈴木秀彦, 堤雅基, 堤雅基, 田口真, 江尻省, 江尻省, 西山尚典, 西山尚典

      日本地球惑星科学連合大会予稿集(Web)2021   2021

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    • THERMOGRAPHY OF ASTEROID 162173 RYUGU BY THERMAL INFRARED IMAGER ON HAYABUSA2

      岡田達明, 岡田達明, 福原哲哉, 田中智, 田口真, 荒井武彦, 坂谷尚哉, 千秋博紀, 出村裕英, 関口朋彦, 神山徹, 嶌生有理

      Thermophysical Properties39th   151‐153   13 11 2018

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    • Observation Plans of Thermal Infrared Imager TIR onboard Hayabusa2 during the Asteroid Proximity Phase

      OKADA Tatsuaki, OKADA Tatsuaki, FUKUHARA Tetsuya, TANAKA Satoshi, TAGUCHI Makoto, ARAI Takehiko, SENSHU Hiroki, SAKATANI Naoya, OGAWA Yoshiko, DEMURA Hirohide, KITAZATO Kohei, KOUYAMA Toru, SEKIGUCHI Tomohiko, SHIMAKI Yuri, HASEGAWA Sunao, MATSUNAGA Tsuneo, WADA Takehiko, IMAMURA Takeshi, TAKITA Jun, AOKI Yuya, SUKO Kentaro, HELBERT Jorn, MUELLER Thomas G, HAGERMANN Axel

      日本地球惑星科学連合大会予稿集(Web)2018   ROMBUNNO.PPS03‐P12 (WEB ONLY)   2018

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    • Detectability Performance of Thermal Infrared Imager TIR on Hayabusa2

      OKADA Tatsuaki, OKADA Tatsuaki, FUKUHARA Tetsuya, TANAKA Satoshi, TAGUCHI Makoto, ARAI Takehiko, SENSHU Hiroki, OGAWA Yoshiko, DEMURA Hirohide, KITAZATO Kohei, NAKAMURA Ryosuke, KOUYAMA Toru, SEKIGUCHI Tomohiko, HASEGAWA Sunao, MATSUNAGA Tsuneo, WADA Takehiko, IMAMURA Takeshi, TAKITA Jun, TAKITA Jun, SAKATANI Naoya, HORIKAWA Yamato, HORIKAWA Yamato, ENDO Ken, HELBERT Jorn, MUELLER Thomas G, HAGERMANN Axel

      日本地球惑星科学連合大会予稿集(Web)2017   ROMBUNNO.PPS02‐P20 (WEB ONLY)   2017

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      門倉昭, 田中良昌, 片岡龍峰, 内田ヘルベルト陽仁, 岡田雅樹, 小川泰信, 佐藤由佳, 田口真, 尾崎光紀, 塩川和夫, 細川敬祐, 三好由純, 元場哲郎, 行松彰, 山岸久雄, 佐藤夏雄

      地球電磁気・地球惑星圏学会総会及び講演会(Web)142nd   ROMBUNNO.S001‐36 (WEB ONLY)   2017

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    • Infrared cameras onboard Venus Orbiter Akatsuki

        26 ( 1 ) 5 - 12   8 2016

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    • 「あかつき」搭載中間赤外カメラによる金星雲頂温度観測

      田口 真, 福原 哲哉, 神山 徹, 今村 剛, 中村 正人, 鈴木 睦, 佐藤 隆雄, 上野 宗孝, 岩上 直幹, はしもと じょーじ, 佐藤 光輝, 高木 聖子

          3 2016

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      第29回大気圏シンポジウム(2016年3月7日-8日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000051002レポート番号: I-2

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    • Road to the first star : Venus orbiter from Japan(26)Arrival at Venus

      Nakamura M., Yamazaki A., Taguchi M., Iwagami N., Satoh T.

      Planetary People25 ( 1 ) 4 - 7   3 2016

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      Language:Japanese   Publisher:The Japanese Society for Planetary Sciences  

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      田口真, 神山徹, 今村剛, 堀之内武, 福原哲哉, 二口将彦, はしもと じょーじ, 岩上直幹, 村上真也, 小郷原一智, 佐藤光輝, 佐藤隆雄, 鈴木睦, 高木聖子, 上野宗孝, 渡部重十, 山田学, 山崎敦, 中村正人

      地球電磁気・地球惑星圏学会総会及び講演会(Web)140th   2016

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    • 一番星へ行こう! 日本の金星探査機の挑戦その29 〜巨大な弓形雲頂温度構造の発見〜

      田口真, 福原哲哉, 今村剛, 神山徹, 二口将彦, はしもとじょーじ, 鈴木睦, 上野宗孝, 岩上直幹, 佐藤隆雄, 佐藤光輝, 高木聖子, 中村正人

      日本惑星科学会誌「遊星人」25 ( 4 ) 2 - 16   2016

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    • TIRによる地球スイングバイ時の地球・月撮像

      岡田達明, 岡田達明, 福原哲哉, 田中智, 田口真, 荒井武彦, 今村剛, 千秋博紀, 小川佳子, 出村裕英, 関口朋彦, 神山徹, 中村良介, 松永恒雄, 長谷川直, 和田武彦, 滝田隼, 坂谷尚哉, 堀川大和, 遠藤憲, HELBERT Jorn, MUELLER Thomas G, HAGERMANN Axel

      宇宙科学技術連合講演会講演集(CD-ROM)60th   ROMBUNNO.1G13   2016

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    • Thermal Infrared Imager TIR on Hayabsua2 and Its In-Flight Performance using Earth-Moon Thermal Images.

      OKADA Tatsuaki, OKADA Tatsuaki, FUKUHARA Tetsuya, TANAKA Satoshi, TANAKA Satoshi, TAGUCHI Makoto, IMAMURA Takeshi, IMAMURA Takeshi, ARAI Takehiko, SENSHU Hiroki, OGAWA Yoshiko, DEMURA Hirohide, KITAZATO Kohei, NAKAMURA Ryosuke, KOUYAMA Toru, SEKIGUCHI Tomohiko, HASEGAWA Sunao, MATSUNAGA Tsuneo, WADA Takehiko, TAKITA Jun, SAKATANI Naoya, HORIKAWA Yamato, ENDO Ken, HELBERT Joern, MUELLER Thomas G, HAGERMANN Axel

      日本地球惑星科学連合大会予稿集(Web)2016   ROMBUNNO.PCG10‐01 (WEB ONLY)   2016

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    • アイスランド~昭和基地共役点観測の現状と将来

      門倉昭, 田中良昌, 佐藤由佳, 片岡龍峰, 岡田雅樹, 小川泰信, 田口真, 尾崎光紀, 細川敬祐, 行松彰, 山岸久雄, 佐藤夏雄

      極域科学シンポジウム(Web)7th   OS_Kadokura_00291_01 (WEB ONLY)   2016

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    • Road to the first star : Venus orbiter from Japan(25)The cameras awaken after 5 years of sleep

      Yamazaki A., Yamada M., Fukuhara T., Ohtsuki S., Taguchi M., Akatsuki project team

      Planetary People24 ( 4 ) 339 - 341   12 2015

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    • C306 「あかつき」搭載中間赤外カメラが目指すサイエンス(「あかつき」金星大気探査カウントダウン,スペシャル・セッション)

      田口 真, 福原 哲哉, 神山 徹, 今村 剛, 中村 正人, 上野 宗孝, 鈴木 睦, 佐藤 隆雄, 岩上 直幹, はしもと じょーじ, 佐藤 光輝, 高木 聖子

      大会講演予講集108   359 - 359   2015

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    • 惑星観測を目指した極周回成層圏テレスコープFUJINの開発

      前田惇徳, 田口真, 荘司泰弘, 中野壽彦, 今井正尭, 合田雄哉, 高橋幸弘, 渡辺誠, 吉田和哉, 坂本祐二

      地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)138th   2015

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    • 火星大気散逸探査(のぞみ後継機)のミッション計画とシステム検討

      松岡彩子, 関華奈子, 寺田直樹, 横田勝一郎, 山崎敦, 阿部琢美, 今村剛, 川勝康弘, 二穴喜文, 平原聖文, 石坂圭吾, 熊本篤志, 栗原純一, 中川広務, 坂野井健, 田口真, 小郷原一智

      日本地球惑星科学連合大会予稿集(Web)2015   ROMBUNNO.PPS05‐01 (WEB ONLY)   2015

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    • 「はやぶさ2」搭載中間赤外カメラTIR:軌道上初期チェックと今後の運用計画

      岡田達明, 田中智, 福原哲哉, 田口真, 今村剛, 荒井武彦, 千秋博紀, 出村裕英, 小川佳子, 北里宏平, 関口朋彦, 中村良介, 神山徹, 長谷川直, 松永恒雄, 和田武彦, 滝田隼, 坂谷尚哉, 堀川大和, HELBERT Jorn, MUELLER Thomas, HAGERMANN Axel

      日本地球惑星科学連合大会予稿集(Web)2015   ROMBUNNO.PCG30‐05 (WEB ONLY)   2015

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    • 火星衛星サンプルリターン機による火星大気観測の可能性

      今村剛, 小郷原一智, 田口真, 山本真行, 笠羽康正, 青木翔平, 坂野井健, 黒田剛史, 笠井康子, 高橋芳幸, 野口克行, 倉本圭

      地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)138th   ROMBUNNO.R009‐26   2015

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    • 紫外線望遠鏡による系外惑星観測の検討

      堀越寛己, 池澤祥太, 桑原正輝, 村上豪, 亀田真吾, 吉川一朗, 田口真

      地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)138th   ROMBUNNO.R009‐P34   2015

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    • Development of the Stratospheric Telescope for Observations of Planets - FUJIN-1 - and Evaluation of the Pointing Control System

      SHOJI Yasuhiro, TAGUCHI Makoto, NAKANO Toshihiko, MAEDA Atsunori, TAKAHASHI Yukihiro, IMAI Masataka, NAKAMOTO Junpei, WATANABE Makoto, GODA Yuya, KAWAHARA Takeshi, YOSHIDA Kazuya, SAKAMOTO Yuji

      JAXA research and development report13   87 - 105   3 2014

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      Seeing is the most important condition for high spatial resolution optical imaging by a ground-based telescope. The stable wind and low atmospheric density in the stratosphere provide ideal environment for optical observations of celestial objects. Taking advantages of the stratospheric environment even a small telescope with a sub-meter diameter main mirror can realize high spatial resolution imaging comparable to those by huge ground-based telescopes with a several-meter diameter. The circumpolar balloon-borne telescope, FUJIN, is a telescope floating in the polar stratosphere for optical observations of planets. Since the FUJIN was proposed in 2002, the flight system has been developed. The first flight test was conducted in 2009 to be failed due to hung-up of the onboard CPU. Improvement and further development has been continued, and then the FUJIN-1 flight model was rolled out in 2013. Unfortunately the flight experiment in 2013 was canceled due to the bad wind condition and some troubles in the balloon control system, respectively. However the functions of the FUJIN-1 were evaluated in the ground tests, and the flight model stood by as`flight ready.&#039;In the tests the pointing control system of the telescope, which is the key mechanism for the FUJIN-1, was tested and evaluated to be capable of suppressing the pointing error within 0.4&quot;(σ) which is smaller than the diffraction limit of the FUJIN-1 main telescope. From these results it has been decided that the development of the FUJIN-1 has been completed, and the development of the FUJIN-2, the flight system for longer flight duration in the northern polar region has been started. In this article the outline of the FUJIN project, the FUJIN-1 flight system and the ground test results of the pointing control functionality are introduced.

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    • 惑星観測を目指した極周回成層圏望遠鏡FUJIN

      前田惇徳, 田口真, 吉田和哉, 坂本祐二, 中野壽彦, 荘司泰弘, 高橋幸弘, 仲本純平, 今井正尭, 渡辺誠, 合田雄哉

      地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)136th   2014

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    • O9-14 超小型深宇宙探査機搭載用ジオコロナ撮像装置の開発(口頭発表セッション9(はやぶさ),口頭発表)

      佐藤 允基, 亀田 真吾, 田口 真, 吉川 一朗, 中村 正人

      日本惑星科学会秋期講演会予稿集2013   "O9 - 14"   20 11 2013

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    • 「はやぶさ2」中間赤外カメラ(TIR)の開発の現状

      岡田達明, 福原哲哉, 田中智, 田口真, 荒井武彦, 千秋博紀, 中村良介, 今村剛, 関口朋彦, 長谷川直, 出村裕英, 小川佳子, 北里宏平, 松永恒雄, 和田武彦, 滝田隼, 坂谷尚哉, HELBERT Joern, MUELLER Thomas, HAGAERMANN Axel

      日本惑星科学会秋季講演会予稿集2013   81   2013

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    • ロングイアビン・オーロラスペクトログラフによるオーロラ・大気光の長期分光観測

      小川泰信, 宮岡宏, 坂野井健, 鈴木臣, 門倉昭, 田口真

      極域科学シンポジウム講演予稿集(CD-ROM)4th   ROMBUNNO.OS,OGAWAYASUNOBU,1   2013

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    • 金星探査機あかつき:中間赤外カメラの観測結果

      福原哲哉, 田口真, 二口将彦, 今村剛, 中村正人, 岩上直幹, 鈴木睦, 上野宗孝, はしもと じょーじ, 佐藤光輝

      日本リモートセンシング学会学術講演会論文集52nd   2012

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    • 「あかつき」中間赤外カメラによって観測された金星雲頂温度分布の特徴

      田口真, 二口将彦, 福原哲哉, 佐藤光輝, 今村剛, 中村正人, 上野宗孝, 鈴木睦, 岩上直幹, はしもと じょーじ

      大気圏シンポジウム・講演集(Web)26th   2012

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    • C154 火星大気散逸探査(のぞみ後継探査)(スペシャル・セッション「惑星大気科学の課題と将来の探査計画」,口頭発表)

      寺田 直樹, 松岡 彩子, 関 華奈子, 阿部 琢美, 石坂 圭吾, 熊本 篤志, 栗原 純一, 坂野井 健, 田口 真, 中川 広務, 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

      大会講演予講集102   2012

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    • 金星夜面雲頂高度の度温度分布に見られる特徴

      二口将彦, 田口真, 福原哲哉, 佐藤光輝, 今村剛, 中村正人, 上野宗孝, 鈴木睦, 岩上直幹

      地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)130th   2011

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    • 「かぐや」による子午面撮像が明らかにしたプラズマポーズの形成

      村上豪, 吉川一朗, 吉岡和夫, 山崎敦, 鍵谷将人, 田口真, 菊池雅行, 亀田真吾, 中村正人

      地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)130th   ROMBUNNO.B006-P009   2011

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    • P008 はやぶさ2搭載用中間赤外カメラ(ポスターセッション2)

      岡田 達明, 中村 良介, 関口 朋彦, 長谷川 直, 北里 宏平, 小川 佳子, 福原 哲哉, 田口 真, 今村 剛, 上野 宗孝, 和田 武彦, はやぶさ2中間赤外カメラチーム

        2010   88   6 10 2010

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    • あかつき搭載中間赤外カメラの性能評価

      二口将彦, 田口真, 福原哲哉, 今村剛, 中村正人, 上野宗孝, 岩上直幹, 佐藤光輝

      地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)128th   2010

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    • 打ち上げ後の金星探査機”あかつき”

      中村正人, 石井信明, 今村剛, 上野宗孝, 鈴木睦, 阿部琢美, 山崎敦, 岩上直幹, 佐藤毅彦, 田口真, 渡部重十, 福原哲哉, 大月祥子

      地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)128th   2010

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    • B205 Longwave Infrared Camera onboard the Akatsuki spacecraft :

      Taguchi M., Sakata K., Futaguchi M., Fukuhara T., Sato M., Imamura T., Nakamura M., Ueno M., Suzuki M., Iwagami N., Mitsuyama K., Hashimoto G. L.

        98   147 - 147   2010

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    • Road to the First Star : Venus Orbiter from Japan (3) : Development of Longwave Infrared Camera

      FUKUHARA Tetsuya, TAGUCHI Makoto, IMAMURA Takeshi

      Planetary people17 ( 1 ) 77 - 79   25 3 2008

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    • 国際宇宙ステーションからの地球超高層大気撮像観測計画

      齊藤昭則, 阿部琢美, 坂野井健, 大塚雄一, 田口真, 吉川一朗, 山崎敦, 鈴木睦, 中村卓司, 山本衛, 河野英昭, 石井守, 星野尾一明, 坂野井和代, 藤原均, 久保田実, 江尻省

      地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)124th   ROMBUNNO.B005-43   2008

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    • Exploration of Venus’ atmosphere and the future of planetary meteorology

      今村剛, 中村正人, 上野宗孝, 佐藤毅彦, 渡部重人, 田口真, 高橋幸弘, 鈴木睦, 岩上直幹, 石井信明, 阿部琢美, 山崎敦, 福原哲哉, 上水一典, 坂野井健, 山田学, 橋本成司

      宇宙科学技術連合講演会講演集(CD-ROM)51st   2007

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    • 惑星宇宙望遠鏡TOPS:計画の概要ならびにサイエンス検討の現状

      高橋幸弘, 坂野井健, 上野宗孝, 笠羽康正, 吉田和哉, 田口真, 山崎敦, 岩上直幹, 今村剛, 鈴木睦, 阿部琢美, 寺田直樹, 寺田直樹, 土屋史紀, 堀之内武, 中島健介, 高橋幸弘, 高橋幸弘

      地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)122nd   2007

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    • Development of the Longwave Infrared Imager(LIR)

      福原哲哉, 田口真, 今村剛, 中村正人, 岩上直幹, 上野宗孝, 鈴木睦, 橋本成司, 佐藤光輝, 山崎敦, 野口一秀, 樫川了一, 東野勇

      宇宙科学技術連合講演会講演集(CD-ROM)51st   2007

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    • 気球搭載望遠鏡による惑星観測計画

      田口 真, 吉田 和哉, 中西 洋喜

      宇宙科学シンポジウム5   396 - 399   6 1 2005

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    • 金星探査機搭載非冷却中間赤外カメラ

      田口真, 今村剛, 中村正人, 岩上直幹, 上野宗孝

      大気圏シンポジウム18th   2004

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    • The Development of the Absorption Cells for the Telescope of Resonantly Scattering Emission by Oxygen Ions.

      山崎敦, 中村正人, 田口真, 川原琢也, 三宅亙, 吉川一朗, 滝沢慶之

      宇宙利用シンポジウム15th   1999

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    • Upper atmosphere physics data obtained at Syowa Station in 1996 (Upper Atmosphere Physics 16)

      Kawana Sachihito, Kikuchi Masayuki, Sakanoi Takeshi, Yumisashi Isamu, Taguchi Makoto

      JARE data reports233   1 - 202   3 1998

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    Research Projects

    • Identification of UV absorbers and derivation of solar heating rate as driving sources of atmospheric circulation of Venus

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

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      4 2021 - 3 2026

      Grant number:21H04522

      Grant amount:\31720000 ( Direct Cost: \24400000 、 Indirect Cost:\7320000 )

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    • Unveiling the material circulation in the Venusian atmosphere with coordinated spacecraft and ground-based observations

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      NAKAMURA MASATO

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      4 2016 - 3 2020

      Grant number:16H02231

      Grant amount:\44980000 ( Direct Cost: \34600000 、 Indirect Cost:\10380000 )

      The atmospheric material circulation on Venus related to cloud formation has been studied by cooperative observations by Akatsuki spacecraft and ground-based telescopes and numerical modeling. We have clarified the structure of the mean meridional circulation and the characteristics of various planetary-scale waves, which may be related to the maintenance of the high-speed zonal flow, by cloud tracking using infrared images covering the whole local time as well as ultraviolet images. We obtained observational clues that angular momentum transport caused by thermal tides contributes to the maintenance of high-speed zonal winds. For integrating observational data with numerical modeling, data assimilation was successfully conducted. The global temperature structure was observed by radio occultation. The cloud physics was introduced into the atmospheric general circulation model, and the distribution of sulfuric acid clouds consistent with the observations was reproduced.

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    • Study on conjugacy of auroral phenomena with high temporal resolution observations

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      Kadokura Akira

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      4 2015 - 3 2020

      Grant number:15H02628

      Grant amount:\27300000 ( Direct Cost: \21000000 、 Indirect Cost:\6300000 )

      During the period of this research project, the 100Hz High-speed Auroral lmager (HAI) and the VLF electro-magnetic wave receiver (VLF) were newly developed, and were installed at Tjornes and Husafell observatories in Iceland. In addition, the Proton Auroral Spectrograph (PAS), the Optical Mesosphere Thermosphere Imagers (OMTI), and an atmospheric electric field measurement system were also newly installed at the observatories as a collaboration with other projects. Maintenance and version-up of other ground-based instruments (e.g., increase of sampling rate of the data logger from 2 Hz to 20 Hz) at both observatories have been also done. Using these various instruments, conjugate observation between Iceland and Syowa Station, together with the Arase satellite, which was launched in December, 2016, has been carried out since March, 2017 until now, and good conjugate data have been successfully obtained so far.

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    • Study on proton aurora by observations at geomagnetic conjugate points

      Grant-in-Aid for Scientific Research 

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      4 2015 - 12 2019

      Grant type:Competitive

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    • Identification of a UV absorber in the Venus atmosphere by a circumpolar stratospheric telescope (FUJIN)

      Grant-in-Aid for Scientific Research 

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      4 2002 - 12 2019

      Grant type:Competitive

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    • Study on the Venus atmosphere by Longwave Infrared Camera onboard a Venus orbiter Akatsuki

      Grant-in-Aid for Scientific Research 

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      1 2001 - 12 2019

      Grant type:Competitive

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    • Study on planetary coronas by hydrogen and deuterium absorption cells

      Grant-in-Aid for Scientific Research 

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      1 1995 - 12 2019

      Grant type:Competitive

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    • 惑星超高層大気リモートセンシングへの応用を目指した無電極吸収・発光セルの開発

      日本学術振興会  科学研究費助成事業 

      田口 真

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      4 2016 - 3 2019

      Authorship:Principal investigator  Grant type:Competitive

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    • 極周回成層圏テレスコープ(風神)を用いた金星大気変動現象の研究

      日本学術振興会  科学研究費助成事業 

      田口 真

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      4 2015 - 3 2018

      Authorship:Principal investigator  Grant type:Competitive

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    • 極周回成層圏テレスコープによる金星大気の研究

      日本学術振興会  科学研究費助成事業 

      田口 真

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      4 2012 - 3 2016

      Authorship:Principal investigator  Grant type:Competitive

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    • Study on the cascade process of the mesoscale plasma structure in the polar ionosphere

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      TAGUCHI Satoshi, HOSOKAWA Keisuke, OGAWA Yasunobu, TAGUCHI Makoto, SHIOKAWA Kazuo, AOKI Takeshi, SUZUKI Shin, TAWARA Atsushi

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      4 2010 - 3 2015

      Grant number:22340143

      Grant amount:\19760000 ( Direct Cost: \15200000 、 Indirect Cost:\4560000 )

      The plasma in the polar ionosphere often forms a mesoscale structure through various processes. In this study we made an all-sky imager having an ability to observe the mesoscale plasma structure and the relevant auroral structure at high time resolution, and analyzed data that were obtained from the imager. We identified the occurrence characteristics of the high-density region in the polar cap, and the nature of its structuring. We also found unprecedented spatial and temporal characteristics of the particle precipitation in the cusp.

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    • Conjugacy of auroras and their relationship to solar activity

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      SATO NATSUO, YAMAGISHI Hisao, KADOKURA Akira, OGAWA Yasunobu, YUKIMATU Akira, ONO Takayuki, HOSOKAWA Keisuke, TAGUCHI Makoto, OKANO Syoichi

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      4 2009 - 3 2014

      Grant number:21403007

      Grant amount:\19240000 ( Direct Cost: \14800000 、 Indirect Cost:\4440000 )

      Syowa Station in Antarctica and stations in Iceland form an ideal set of observatories to study geomagnetically conjugate auroras in the auroral zone. A campaign of conjugate auroral observations using all-sky TV cameras has been carried out during the equinox periods. We examined several types of auroras, e.g., beads aurora, auroral breakup, spirals, and pulsating aurora, checking for similarity and dissimilarity in terms of shapes, movements, and luminosity variations at both observatories. We assumed their generation region and mechanisms. We were also able to trace the temporal movements and displacement of the auroras in the Northern and Southern Hemispheres with a high spatial-temporal resolution. We discussed their conjugate characteristics with reference to solar wind-magnetosphere and magnetosphere-ionosphere coupling processes.

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    • 惑星大気・プラズマ圏現象の長期連続観測を目指した極周回成層圏テレスコープの開発

      山田科学振興財団  山田科学振興財団研究助成金 

      田口 真

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      4 2011 - 3 2013

      Authorship:Principal investigator  Grant type:Competitive

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    • 電離圏電子密度モニターを目指した衛星搭載真空紫外シュミットカメラの開発

      日本学術振興会  科学研究費助成事業 

      田口 真

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      4 2009 - 3 2012

      Authorship:Principal investigator  Grant type:Competitive

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    • Transit Observations of Exoplanets with Antarctic Infrared Telescope

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      TAKASHI Ichikawa, YASUMASA Kasaba, TAKESHI Sakanio, NARUHISA Takato, HIDEAKI Motoyama, MAKOTO Taguchi

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      2009 - 2011

      Grant number:21244012

      Grant amount:\43550000 ( Direct Cost: \33500000 、 Indirect Cost:\10050000 )

      In order to perform transit observations of exo-planets at Antarctica, we developed 40cm infrared telescope and camera. The instruments were deployed at Dome Fuji station of National Institute of Polar Research. In addition, the stage of 9m height was constructed, on which astronomical conditions were observed. We obtained the smallest seeing size ever taken at good astronomical sites. The results were published in main journals and were presented at the Astronomical Society of Japan.

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    • Spectroscopic study on aurora and airglow

      Grant-in-Aid for Scientific Research 

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      9 1996 - 3 2010

      Grant type:Competitive

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    • Multi-dimensional Simultaneous Observations of the Geospace-Ionosphere Phenomena using Low-Altitude Polar Satellites and Ground-Based Facilities

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      HIRAHARA Masafumi, ASAMURA Kazushi, YAMAZAKI Atsushi, SHINOHARA Iku, SAKANOI Takeshi, KASABA Yasumasa, OKANO Syoichi, MIYAOKA Hiroshi, KADOKURA Akira, OKADA Masaki, OGAWA Yasunobu, SAITO Akinori, NOZAWA Satonori, SEKI Kanako, SHIOKAWA Kazuo, IEDA Akimasa, KIKUCHI Takashi, OYAMA Shin-ichiro, EBIHARA Yusuke, TAGUCHI Makoto, HOSOKAWA Keisuke, WATARI Shinichi, MURATA Takeshi

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      2007 - 2010

      Grant number:19403011

      Grant amount:\15730000 ( Direct Cost: \12100000 、 Indirect Cost:\3630000 )

      A micro-satellite of the Japanese mission was successfully launched from Baikonur Cosmodrome in Kazakhstan on August 23, 2005. We can simultaneously observe spatial distribution and time variation of fine aurora emissions associated with auroral electron precipitation and ionospheric ion outflows with a full pitch-angle coverage and a high-time resolution. Our Reimei team has also started some collaborative observations with EISCAT, all-sky cameras, and SuperDARN. Almost every new moon interval, we have been achieving simultaneous observations with Reimei and the ground-based instruments.

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    • Role of ionospheric process on the conjugate auroral dynamics and intensity

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      SATO Natsuo, YAMAGISHI Hisao, MIYAOKA Hiroshi, KADOKURA Akira, OKADA Masaki, ONO Takayuki, HOSOKAWA Keisuke, EJIRI Masaki, MOTOBA Tetsuo, TAGUCHI Makoto, EBIHARA Yusuke, TONEGAWA Yutaka, OKANO Shoichi

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      2005 - 2008

      Grant number:17403009

      Grant amount:\15430000 ( Direct Cost: \13300000 、 Indirect Cost:\2130000 )

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    • マイクロサテライトが拓くスプライト及び雷放電逃走電子の科学

      日本学術振興会  科学研究費助成事業 

      高橋 幸弘, 坂井野 健, 吉田 和哉, 中西 洋樹, 高島 健, 田口 真

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      2005 - 2008

      Grant number:17204042

      Grant amount:\41340000 ( Direct Cost: \31800000 、 Indirect Cost:\9540000 )

      雲地上間の雷放電に伴う上空放電のひとつであるスプライトと呼ばれる現象は、1990年の最初の報告以来、精力的な研究が、観測、理論の両面から続けられている。しかし、これまでの地上観測ではスプライトを真下から見ることができないため、その水平構造については三角測量観測による数例しか調べられていない。一方、高エネルギー電子によって放射される地球ガンマ線が、雷雲活動に同期して人工衛星で観測されている。本研究では、CMOS及びCCDイメージャーとガンマ線センサーを搭載した、スプライト・地球ガンマ線観測専用のマイクロサテライトを開発、打ち上げ、それらの解明を目指す。検討の結果、本計画では、衛星を50cm立方、40kg級に変更することとした。2006年度は、以下の機器開発、校正、環境試験を実施するとともに、TLEおよびTGF観測戦略を作成するために、それらの地上および衛星観測データの解析を行い、海外研究者と議論する機会をもった。
      1.搭載機器の製作・環境試験・校正
      2005年度に引き続き、CMOS及びCCDを用いた超小型・軽量のイメージセンサーの製作・環境試験、及び校正を行い、ソフトウェアも含め、フライト品の製作に目途をつけた。また、米国カリフォルニア大学サンタクルズ校のスミス博士の助言に基づき、ガンマ線センサーの最終的な仕様を確定した。
      2.衛星BUSの設計・開発および環境試験
      BUSの最終設計を完了し、各パーツのフライト部品の仕様決定・購入を行った。必要部品を購入して構造モデルを製作し、振動試験を実施した。
      3.海外研究者との打合せおよび成果発表
      10月にフランスを訪れ、同様の衛星計画(打上は本計画の3年後)を持つフランスチームと会合を持ち、観測戦略についての意見交換を行った。また、12月のAGU(米国)学会に参加し、研究経過の発表(招待講演)と、海外研究者(スミス博士及びイナン教授他)と議論を行った。

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    • 気球搭載望遠鏡による惑星大気・プラズマの研究

      日本学術振興会  科学研究費助成事業 

      田口 真

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      4 2005 - 3 2007

      Authorship:Principal investigator  Grant type:Competitive

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    • Evaluation of the effects of global lightining activity on the middle/upper atmosphere and atmosphere and the ionosphere/magnetosphere

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      TAKAHASHI Yukihiro, FUKUNISHI Hiroshi, MURATA Isao, FUJIWARA Hitoshi, MAKITA Kazuo, TAGUCHI Makoto

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      2003 - 2005

      Grant number:15403011

      Grant amount:\14600000 ( Direct Cost: \14600000 )

      In this research we have carried out optical and radio wave observations of lightning- induced TLEs (transient luminous events) in the middle and upper atmosphere, including sprites and elves, under international collaboration in order to clarify the generation mechanisms of TLEs and to understand their global effects both in electromagnetic and chemical point of view.
      1. Sensor installation and steady observation in Scandinavia
      We visited ESRANGE observatory in Kiruna, Sweden in 15 FSY and carried out maintenance/ of CCD camera, installation of ELF and VLF receivers. In 16 and 17 FSY, we visited there again and carried out the maintenance and adjustments. The continuous data acquisition have been carried out up to now successfuly.
      2. Extension and steady operation of world wide ELF network
      In addition to the ELF systems both at Syowa, Antarctica and Onagawa, Japan, we installed 2 more systems at Kiruna (FSY 15) and at Santa Cruz, California, USA (FSY 17). The system consisting of 4 stations is quite unique and the most useful network for lightning detection in estimating charge moment of lightning.
      3. Optical measurements of TLEs by FORMOSAT-2/ISUAL and data analysis
      Taiwanese satellite FORMOSAT-2 was launched successfully on 20 May, FSY of 16. FORMOSAT-2 carries 3 sprites/lightning optical equipments and its health is in good condition since the start of observation. The analysis shows the first global distribution of TLEs (sprites, elves) and absolute electron energy in TLE for the first time.
      4. Estimation of chemical effects of TLEs and lightning based on computer simulation
      We carried out the computer simulations to examine the physical mechanisms and to estimate the chemical effects on the ambient atmosphere. In addition, we visited University of Bremen, Germany and discussed about comparison between the chemical measurement with satellite and ELF network data.

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    • Studies on magnetospheric boundary processes based on magnetic field and aurora observation in the northern and southern polar caps

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      FUKUNISHI Hiroshi, SAKANOI Takeshi, TAKAHASHI Yukihiro, OKANO Shoichi, TAGUCHI Makoto, YAMAGISHI Hisao

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      2000 - 2002

      Grant number:12573007

      Grant amount:\14700000 ( Direct Cost: \14700000 )

      In order to clarify the interaction between the solar wind and the magnetosphere of the Earth, magnetospheric boundary processes were investigated, making use of 6 non-manned automatic geophysical observatories (AGO) located in the interior of the Antarctic Continent. Comprehensive analysis was carried out, combining data recorded by AGO equipments, such as magnetometers, aurora imagers, riometers and VLF receivers, and solar wind and solar activity data obtained by spacecrafts as well as HF radar data at Syowa station. Results including some important and new findings are as follows:
      1) Conjugate TCV (traveling convection vortices) events moving sunward in both hemispheres were found and its physical mechanisms were investigated in detail.
      2) Transient ionospheric disturbances relating to the TCV were found. It is shown that the disturbances are consequence of non-linear processes in F-region caused by 3-D current system and auroral particle precipitations.
      3) Automatic detection algorithms for MIE (magnetic impulse event) and for TD (tangential discontinuity) were developed successfully.Using these algorithms,it was found that occurences of MIE and TD show correlation in seasonal variation.
      4) A tecchnique to calculate the TD arrival time using data obtained by one spacecraft was developed.
      5) Quantitative model for TCV phenomena considering conjugate condition in the magnetosphere-ionosphere coupling processes was constructed.
      6) 3-D MHD simulation was conducted to understand the current generation mechanisms associated with TCV. The results succeeded in reproducing typical TCV phenomena.

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    • Auroral and thermosphere dynamics at South Pole

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      EJIRI M, OKADA M, TAGUCHI M, ASO T, TSUTSUMI M, YUKIMATSU A

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      1999 - 2000

      Grant number:11691137

      Grant amount:\5400000 ( Direct Cost: \5400000 )

      We have developed an all-sky-imajor (ASI) which has been operative at the Amundsen-Scott South Pole Station during 1999 to 2000 austral winter seasons. The fundamental operation has been carried out from our Institute through the satellite internet. All data are successfully obtained and their archived data-base are open to scientific community over the world.
      M.Okada, Y.Suzuki and S.Takeshita have been at the Amundsen-Scott South Pole Station for ASI maintenance, calibration, raw data collection, and giving an instruction to technicians who were staying there over the winter. All logistics are provided through the National Science Foundation, U.S.A.under the Agreement with our Institute.
      We have found the new auroral dynamics associated with the magnetospheric disturbance, which have been also revealed by the conjunction with HF radar observations.
      These preliminary results have been presented at AGU (American Geophysical Union), EGS (European Geophysical Society), COSAR and other symposiums.
      As for the conjunction of the auroral studies with other projects, we have performed the joint operation with HF radar, the satellite (DMSP) as well as the ground instruments at Chinese Zhongshan Station and ALIS (Auroral Large-scal Imaging System) in Sweden.

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    • Studies on dynamical processes among Mercury's atmosphere, magnetosphere and the solar wind based on 2D imaging observations for Mercury's atmospheric emissions

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      MISAWA Hiroaki, TAGUCHI Makoto, MORIOKA Akira

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      1999 - 2000

      Grant number:11640438

      Grant amount:\3600000 ( Direct Cost: \3600000 )

      1) Development of the 2D imaging system for atmospheric emission of Mercury
      The 2D imaging system for detection of Na-D line emission of Mercury's atmosphere is successfully developed. The back-end of the system consists of temperature and tilt-angle controlled interference filter and electrically cooled 2D CCD camera. The band-width of the filter is only 0.13nm (FWHM) for reducing the contamination caused by continuum emissions from the day-side area of Mercury. The temperature control function is used for adjusting the center wavelength of the filter against changes in ambient temperature, while the tilt-angle control function is used for changing the center wavelength in a short time to observe both a Na-D line image and back-ground emission image as a reference. The back-end is attached to the 60cm φ F/24 coude telescope system of Tohoku University.
      2) Observations of Na-D line emission of Mercury's atmosphere
      The observations were made from Nov. to Dec. 2000. Due to small solar elongation of Mercury, the observations were made in the twilight period at low elevation angle. The trackingg error of the telescope system was therefore inevitably large. The error has not been fully compensated during this research period, then, reliable images have not been acquired successfully. However, we have established analysis methods which are required to derive 2D image of Mercury's atmosphere ; i.e., the compensation method for atmospheric smearing and the reduction method of back-ground emission.
      3) Development of Monte-Carlo simulation model for Mercury's atmosphere
      A Monte-Carlo simulation model for neutral and ionized particles has been developed under the consideration of gravity forces of Mercury and the sun and the presence of magnetic field of Mercury. Three main gas release processes are taken into account in the model ; photon-stimulated desorption, ion sputtering and meteoritic vaporization. Although quantitative investigations of dynamical processes among Mercury's atmosphere, magnetosphere and the solar wind are deferred for future studies due to lack of reliable data, a significant model has been established in this research.

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    • Study on electromagnetic environment using EISCAT radar

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      ASO Takehiko, OKANO Shoichi, SATO Natsuo, EJIRI Masaki, SATO Kaoru, YAMAGISHI Hisao

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      1998 - 2000

      Grant number:10045033

      Grant amount:\6800000 ( Direct Cost: \6800000 )

      In the 1^<st> year, a collaborative research work with Univ. Tromso on the atmospheric tide and gravity wave behaviors in the polar mesosphere and lower thermosphere was made by using the EISCAT radar observation and data. In March, 1999 a conjunctive and conjugate observation of high-latitude auroras by EISCAT, HF radars, satellites as FAST and GEOTAIL and ground-based optics was carried out in this project and interesting substorm event was successfully captured. In the 2^<nd> year of this project, an intensive study on the electrodynamics of aurora in the polar cap region was started by using the conjunctive observation data to find out possible mechanisms of substorms and relevance of strong arc, electric field and field-aligned current. An analysis of tidal features in the polar mesospheric regions indicates existence of diurnal propagating tide at higher latitudes. A study on the ionospheric trough morphology and detailed analysis of plasma lines were also made. Auroral tomography and HF radar campaign runs were carried out in conjunction with the EISCAT radar, and auroral/airglow spectrograph observation has started its operation to be in close collaboration with EISCAT radar run. In the last year, ion-drag induced neutral instability based on the EISCAT radar data and global feature of atmospheric tide such as assumed contribution of non-migrating semidiurnal tides by using EISCAT long run data in August, 1999 and other radar data has been put to people's attention along with collaborations on SOUSY radar study of gravity wave and turbulence in the stratosphere and analysis of PMSE data by the EISCAT radar. Tomographic reconstruction of heating-induced airglow was also done through collaborative researches. A new meteor radar observation and temperature measurement by airglow spectrograph have also been undertaken to contribute to the coordinated observation of arctic environmental study by the EISCAT radar.

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    • Joint Study on the M-I Coupling in the Southern Polar Cap

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      FUKUNISHI Hirishi, OKANO Shoichi, YAMAGISHI Hisao, SATO Natsuo, TAKAHASHI Yukihiro, TAGUCHI Makoto

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      1997 - 1999

      Grant number:09044053

      Grant amount:\7900000 ( Direct Cost: \7900000 )

      Data obtained by Automatic Geophysical Observatories (AGOs) located at Antarctic high latitude areas in the period of 1993 - 1997, such as aurora image, geomagnetic field, CAN, and VLF waves, have been analyzed carefully in order to investigate the mechanisms of aurora and geomagnetic activities in polar cap region, comparing with Super DARN HF radar network and satellite data. The most important findings are as follows : 1) Pc 1 bursts occur in polar cap region as well as cusp and cleft region, accompanying an impulsive geomagnetic variation caused by geomagnetic reconnection. 2) Pc 3 waves are frequently observed during daytime near 70 degree in geomagnetic latitude, while around 80 degree local time dependency of Pc 3 is comparably small. Based on the comparison with interplanetary magnetic field (IMF) it is inferred that Pc 3 source is located at upstream of shock front and the Pc 3 penetrates into the magnetosphere from subsolar region for small cone angle case while from high latitude in the tail region or low latitude boundary layer (LLBL) for large cone angle case. 3) Dynamic spectrum of Pc 5 in geomagnetic latitude range of 72 - 74 degree sometimes shows an arch structure caused by odd resonance wave. The occurrence frequency of Pc 5 becomes large in northward IMF condition, which implies relationship between generation of Pc 5 and geomagnetic reconnections. 4) Magnetic impulse event (MIE) occurs in the convection reversal boundary of 4 cell pattern observed in the case of northward IMF. MIE travels westward by 60 degree in longitude at a speed of 2 km/sec.

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    • 南極点に於けるオーロラと大気光ダイナミックスの研究

      日本学術振興会  科学研究費助成事業 

      江尻 全機, 堤 雅基, 岡田 雅樹, 田口 真, 岡野 章一, 麻生 武彦, 行松 彰

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      1997 - 1998

      Grant number:09041115

      Grant amount:\3700000 ( Direct Cost: \3700000 )

      1996年に南極点基地に設置された超高感度全天イメージャ(ASI)に、昨年に引続き、1998年南半球冬期にらいても稼働する事が出来た。人工衛星を経由してのインターネットを使用し、基本的なオペレーション・コマンドの送出と、1日数枚のクイック・ルック画像の取得を行って、正常な機器の運用を行うことが出来た。但し、全データは光磁気ディスクに蓄積されているのでそのデータ回収、さらに1年毎の機器メンテナンス(感度較正、テープ装置の設置、焦点調整等)の為、1998年11月に田口をアムンセン・スコット南極点基地に派遣した。南極域での輸送等については、国立極地研究所と米国科学アカデミィー(NSF)との協定で米国南極観測事業の一環として実施された。田口は12月初旬所期の作業及び現地支援要員の訓練も終え無事帰国した。昨年得られたデータから、昼間側カスプ/クレフト帯のオーロラの動きと高エネルギー粒子の動きの新しい観測事実が明らかになってきた。その解析結果は、江尻により第25回欧州光大気科学国際会議で発表し(1998年9月)、さらに海外の共同研究者マイク・テーラー博士と得られた結果についての検討会を持つことが出来た。同会議で麻生は、南極点との共役にあたる北極域でのオーロラ観測結果とそのオーロラの立体構造の再構成法と成因について発表した。磁気圏全体のダイナミックスの視点で南極点での観測結果を見る必要がある。その全体計画等は、江尻により1998年7月名古屋で開催されたCOSPARでも発表された。さらに共同研究者による研究成果発表は米国地球物理連合年次大会をはじめ多数あり、近々成果報告書として出版する予定である。一昨年の全データはホームページhttp://www.nipr.ac.jp/〜asi-dp/にて全世界の研究者に公開されている。

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    • 北方圏における地球環境変動に関する共同研究

      日本学術振興会  科学研究費助成事業 

      田中 正之, SENTMAN D.D., 大竹 政和, 坂野井 健, 佐藤 春夫, 福西 浩, 吉本 和生, 長谷川 昭, 高橋 幸弘, WYSS M., MUCNUTT S.R., STRINGER W.J, BISWAS N.N., HANSEN R.A., SHAW G.E., BENNER R.L., STAMNES K., 田口 真, AKASOFU S.ーI, DEEHR C.S., 青木 周司, 早坂 忠裕, 川村 宏, 中澤 高清, SMITH R.W., 渡部 重十, 花輪 公雄

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      1996 - 1998

      Grant number:08045020

      Grant amount:\6800000 ( Direct Cost: \6800000 )

      東北大学理学部・同理学研究科とアラスカ大学フェアバンクス校との部局間協定にもとづき、本年度の北方圏における地球環境変動に関する共同研究は、(1)オーロラと超高層大気の研究、(2)雷放電発光現象の研究、(3)成層圏オゾン層の研究、(4)地震・火山の研究を中心に行なった。まず、(1)オーロラと超高層大気の研究では、通信総合研究所が開発したプロトンオーロライメージャーを1999年2月にアラスカ大学地球物理学研究所ポーカーフラット観測所に設置し観測を行った。さらに昼側カスプ領域のオーロラのロケット・地上同時観測のために東北大学のプロトンオーロライメージャーを1月にノルウェー・スバールバルに設置し、共同観測を実施した。これらの観測から得られたデータの共同解析を現在行っている。(2)雷放電発光現象の研究では、1998年7月〜8月にコロラドでスプライト・エルブス発光現象の共同観測を実施した他、1998年5月にアラスカ大学より1名を招へいし、1997年度に得られた雷発光現象データの共同解析を行った。(3)成層圏オゾン層の研究では、1997年2月〜5月の間にポーカーフラットで東北大学のレーザーヘテロダイン分光計を用いて実施したオゾン、一酸化二窒素、メタン観測のデータとADEOS衛星データの比較を行った。(4)地震・火山の研究では、アラスカ大学地震観測ネットワークで得られたデータと東北大学地震観測ネットワークで得られたデータの共同解析を実施し、発震メカニズムや地震予知のための研究を行った。

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    • Measurements of the vertical distributions of ozone and related species using high resolution FTIR

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      NAKAJIMA Hideaki, MURATA Isao, TAGUCHI Makoto, KOIKE Makoto, KONDO Yutaka

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      1996 - 1997

      Grant number:08640559

      Grant amount:\2200000 ( Direct Cost: \2200000 )

      We installed the Tunable Diode Laser Heterodyne Spectrometer (TDLHS) at Moshiri Observatory, Nagoya University in October, 1996. Measurement of Solar infrared spectra using TDLHS and Fourier-Transform Infrared Spectrometer (FTIR) were made for two weeks simultaneously. Absorption spectra of several trace molecules such as O3, N2O,HCl, HF,and HNO<@D23@>D2 were taken. Also ozonesonde measurements were conducted at Moshiri Observatory. Vertical profiles of volume mixing ratios (VMRs) of O3 were retrieved from these high-resolution solar spectra. The VMR profile retrieval is based on an iterative inversion algorithm, which utilizes line-by-line, layr-by-layr calculations. Eighty ozone vertical profiles were retrieved from the two spectral regions from 40 spectra and were compared with 17 ozonesonde measurements from a nearby station. Average differences between 18 and 34 km were less than (]SY.+-。[) 12%. The standard deviation of the average differences between 18 and 34 km were less than 20%. Effects of several different factors on errors of profile retrievals, such as initial guess, temperature profiles, and instrument line shape functions, were evaluated by numerical simulation. The estimated errors were extremely consistent with the observed errors between 18 and 34 km, suggesting that the FTIR was optically well adjusted. In general, it was found that retrieval of the O3 profile gives VMRs in an accuracy better than 40% at 14 km, improving to 10-15% between 18 and 30 km, with precision of 30% and 20% for these altitude ranges, respectively.

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    • Lightning Induced Optical Emissions in the Middle Atmosphere

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      WATANABE Shigeto, YUMOTO Kiyofumi, TAKAHASHI Yukihiro, FUKUNISHI Hiroshi, LYONS W.A., INAN U.S.

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      1996 - 1997

      Grant number:08044053

      Grant amount:\4400000 ( Direct Cost: \4400000 )

      Observations of optical phenomena at high altitude above thunderstorms using a multichannel high-speed photometer and image intensified CCD cameras were carried out at Yucca Ridge Station (40゜40'N, 104゜59'W), Colorado. The new measurements indicate that diffuse optical flashes with a duration of <1ms and a horizontal scale of 〜100-300km occur at 75-105km altitude in the lower ionosphere just after the onset of sprites. Here we designate these events as "elves" to distinguish them from "red sprites". This finding is consistent with the production of diffuse optical emissions due to the heating of the lower ionosphere by electromagnetic pulses generated by lightning discharges.
      Optical and search coil magnetometer data were obtained from the SPRITES'96 campaign carried out at Yucca Ridge Field Station, Colorado in July 1996. We have presented clear evidence for the excitation of ULF transients with their dominant power at 1-2 Hz by strong lightning discharges producing elves and sprites without preceding elves and the case of sprites with preceding elves. In the former case, damped quasi-sinusoidal oscillations commence impulsively at the onset of sprites, while in the latter case quasi-sinusoidal wavelets with a duration of 〜3 s are excited, and elves and sprites occur within each wavelet. It is lucky that these ULF transients are due to the nonlinear excitation of the ionospheric Alfven resonator by strong lightning discharge.

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    • レーザーヘテロダイン分光法による大気微量成分の研究

      科学研究費補助金 

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      1 1991 - 8 1996

      Grant type:Competitive

      波長可変半導体レーザーを用いた赤外レーザーヘテロダイン分光計を開発し、太陽を光源として大気中のオゾン、一酸化二窒素、メタンの吸収線プロファイルを測定し、それらの分子の高度分布を導出した。

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    • Joint study on Polar Cap Disturbances Using AGO Network

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      FUKUNISHI Hiroshi, TAKAHASHI Yukihiro, TAGUCHI Makoto, WATANABE Shigeto, YAMAGISHI Hisao, SATO Natsuo, HAYASHI Kanji, ARAKI Tohru, LANZEROTTI L.J, INAN U.S, ROSENBERG T.J, MCLENNAN C.G, ENGEBRETSON M.J, DOOLITLE J.H, WOLFE A

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      1995 - 1996

      Grant number:07044053

      Grant amount:\5100000 ( Direct Cost: \5100000 )

      Auroras and geomagnetic disturbances have been investigated at Automatic Geophysical Observatories (AGO) in the polar cap region where nobody had installed the instruments to observe those phenomena. We developed the instruments to observe auroras and geomagnetic disturbances and operated at 6 AGO stations with corroborations with scientists of the United States. The activities are as follows.
      1. Developments of search coil magnetometer and photometer
      We made two search coil magnetometers for back up of magnetometers operated at AGO stations. We also made photometers with very high data sampling.
      2. Tests of search coil magnetometer and photometer
      Fukunishi, Takahashi and Fujito checked magnetometers and photometers at Yucca Ridge of Colorado, USA with a group of Stanford University. We obtained good sensitivities to observe auroras and geomagnetic disturbances at AGO stations.
      3. Set up at AGO station
      On October, 1995, we set up our search coil magnetometers for AGO-5 and AGO-6 stations at MacMurdo station of Antarctica.
      4. Analyzes of AGO data
      On December, 1995, Fukunishi and Takahashi visited Stanford University to analyze the data of auroras, magnetic fields and ELF-VLF waves obtained at AGO stations. On December, 1996, Fukunishi and Katsuyama visited Stanford University again to analyze the AGO data in detail. Fukunishi visited Laboratory of Antarctica of UK to analyze the AGO data and to have discussions on August, 1996. Prof.Engebretson of Augsburg University visited Tohoky University to compare between his obtained flux gate magnetometer data and our search coil magnetometer data.
      5. Discussions of publication and future work
      Fukunishi visited Church University of UK to present our results and future plan on August, 1996 and stayd for one week. Fukunishi and Katsuyama visited Stanford University to discuss future plan on December, 1996.
      We found new results from the detailed analyzes of AGO data. One of the interesting results is the correlations between magnetic impulse events (MIE) and Pc 1 bursts. We analyze the events in detail with Dr.Lanzerotti of Bell Laboratory and Prof.Engebretson of Augsburg University who indicates the good correlations between MIE and ELF-VLF waves. All instruments are still working well at 6 AGO stations. We are investigating our AGO data with satellite and radar data. Those results will provide us more large progress in understanding polar cap phenomena.

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    • Observations of Polar Aerosols at Alaksa and Spitsbergen : Its influence on the global environmental change

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      SHIBATA Takasi, BRAATHEN G.O, SHAW G, NEUBER R, MIRIMOTO Shinji, WADA Makoto, FUJIWARA Motoo, OKANO Shouiti, TAGUTI Makoto, HUKUNISI Hirosi, OSADA Kazuo, HAYASI Masahiko, MATSUNAGA Katuji, IWASAKA Yasunobu, YASUI M

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      1995 - 1996

      Grant number:07041100

      Grant amount:\24800000 ( Direct Cost: \24800000 )

      The main purpose of this project is the research of the polar stratospheric clouds over Arctic region. We have obtained the following results by the research of the two years : 1) The vertical profiles of PSCs over spitsbergen were observed in the two winter seasons on 1995/1996 and 1996/1997.2) The vertical profiles of ozone over Fairbanks, Alaska were observed in the same winter seasons. 3) The aerosol profiles over Fairbanks were observed by lidar in two years between April 1995 and March 1997.4) The aerosols were directly sampled near the ground level in the same period of the observations of PSCs. The components of the aerosols were obtained by the Chemical analysis. The followings have been found by the results above : 5) The large size liquid PSC particles are often found in the Arctic PSCs. 6) Those PSCs are specially formed when the ambient temperature is dropped near the frost point of ice.
      It is reported that the stratospheric ozone was largely depleted over Arctic in the winter 1995/1996. The homogeneous reaction over the PSC particle are thought as the main process that causes the ozone loss. The liquid particles mentioned in 5) would playd major roll in the process. The lidar observed data will geve us precious data set to study the heterogeneous process.

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    • Observation of ozone in the Arctic upper stratsophere

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      OKANO Shoichi, GERNANDT Hartwig, YAJIMA Nobuyuki, NAKAJIMA Hideaki, KOIKE Makoto, KONDO Yutaka, TAGUCHI Makoto, FUKUNISHI Hiroshi

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      1995 - 1995

      Grant number:07041080

      Grant amount:\2900000 ( Direct Cost: \2900000 )

      1.Observation of ozone profiles in the arctic summer stratosphere was carried out at Ny Alesund in Spitzbergen, Norway in 1995 using an optical ozone sensor on board a BT-5 high altitude balloon.Two personnels were sent to the site for this observation.Four launches were as follows and good data were obtained for each launch.
      'ECC on board' means ECC was on the same balloon to make a comparative measurements and 'ECC on rubber balloon' means concurrent launch of ECC with a rubber balloon.
      2.Ground observation of ozone chemistry related atmospheric minor constituents ; HCl, HF,HNO_3, O_3, ClONO_2, CH_4 and N_2O in the arctic winter was made at Kimura, Sweden in March 1996 with a FTIR.One personnel was sent to the site.
      3.Results from observations in the arctic, except for the ground observation at Kiruna whose data have not been processed yet, have been examined as follows :
      (1) Comparison of ozone profiles obtained with an optical sensor and an ECC ozonesonde showed that both profiles agree well each other below 30km and that a distinct structure around 40km was seen in the optically obtained profile while ECC profile above 30km decreases monotonically with altitude.This indicates that ozone profiles can be obtained with the optical method even above 40km while ECC becomes unreliable due to its low pumping efficiency in high altitudes.
      (2) Ozone profiles up to the upper stratosphere in the arctic have been obtained in two summers including 1995.

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    • Development of an optical ozonesonde for observations of ozone densities in the upper stratosphere

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      FUKUNISHI Hiroshi, TAGUCHI Makoto, OKANO Shoichi

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      1994 - 1995

      Grant number:06554016

      Grant amount:\8700000 ( Direct Cost: \8700000 )

      In FY 1994, an optical ozonesonde which has a channel with an ultraviolet bandpass filter at 302 nm for ozone measurement and a channel with a visible bandpass filter at 420 nm for correction of atitude of the ozonesonde. Prior to a ballon experiment, temperature dependence of detectors and amplifiers were measured using a temperature stabilized chamber. Balloon experiments to measure stratospheric ozone using the optical ozonesondes were conducted at Sanriku Balloon Center of Institute for Space and Astronautical Science in May, August and October and in Spitsbergen, Norway in July, 1994. We evaluated the results of these experiments and found that following improvements are necessary to obtain a prisice ozone profile : 1) improvement in design and material of the diffuser plate, 2) improvement in the low-pass filter to remove noise on the obtained data, 3) a black disk to prerent light reflected by a balloon from entering into the diffuser plate. We performed balloon experiments with the improved optical ozonesondes at Sanriku Balloon Center in September 1995 and January 1996.
      Ozone variations with an altitude scale of several kilometer have been found in our data. It is concluded that the optical ozonesonde technique has been established by this study.

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    • Optical study on the thermo-ionospheric equatorial anomaly

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      OGAWA Toshihiro, KIYAMA Yoshitaka, TAGUCHI Makoto, OKANO Shoichi, FUKUNISHI Hiroshi, KITA Kazuyuki, IWAGAMI Naomoto

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      1993 - 1995

      Grant number:05041055

      Grant amount:\9000000 ( Direct Cost: \9000000 )

      To implement one of the research projects on "Energy and Dynamics of Coupled Ionosphere-Thermosphere System" of Japanese Solar-Terrestrial Energy Program (STEP), we focused on the dynamics of the fine structures of ionospheric F-region plasma in the equatorial anomaly which appears as anomalously high electron densities in the zones of geomagnetic latitudes (]SY.+-.])15゚. We were able to observe the fine structures of F-region electron density distribution and thermospheric temperature and wind system using an optical sensing technique to measure the all-sky distribution of the intensity, line width and line shift of the atomic oxygen 630m airglow that is excited through the recombination of molecular ions and electrons. The observations were made at the top of Mt. Haleakala, Maui Is., Hawaii located at the north zone of the equatorial anomaly, and Watukosek in East Java of Indonesia located in the south zone of the equatorial anomaly.
      We stayd at the observatory on the top of Mt. Haleakala in February 1993 and November 1993,1994 and 1995 to measure the all-sky intensity distributions of the atomic oxygen 630nm and 557.7nm, Na 589.3nm and OH band airglows using an all-sky rapid-scanning photometer and a monochromatic all-sky imager, and to measure the line width and shift of the 630nm airglow. These measurements provided us with all-sky structures of electron density in the F-region, neutral species in the lower thermosphere, and thermospheric temperature and wind system. We found that the horizontal distribution in the F-region electron density varied independently on those structures in the lower themosphere during a magnetic storm, suggesting that a wave disturbance responsible for the electron density variation does not come from the lower atmosphere.
      We set up a meridional scanning photometer at Watukosek and asked a technician at LAPAN Watukosek Observatory to measure the 630nm and OH airglows. We visited Watukosek several times during this project to repair the photometer. A north-south oriented stripe structure of the 630nm airglow was observed from time to time. This structure which is one of the typical manifestations of the F-region plasma is found to be not correlated with that of the OH airglow, suggesting that the lower atmosphere is not responsible for generating this stripe structure.

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    • Study on Magnetic Disturbances in the Southern Polar Cap

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      FUKUNISHI Hiroshi, DOOLITTLE J.h., LANZEROTTI L.j., ROSENBERG T.j., TAGUCHI Makoto, ONO Takayuki, YAMAGISHI Hisao, HAYASHI Kanji, ARAKI Tohru

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      1993 - 1994

      Grant number:05044032

      Grant amount:\4500000 ( Direct Cost: \4500000 )

      AGONET Meeting was held at Rome in Italy from August 28 thorugh September 3,1994. Hiroshi Fukunishi attended the meeting as the representative of the Japanese science group. Utility of science data taken by the AGOs was discussed. It is agreed at the meeting that a database of AGO science data will be constructed in Augsburg College for easy access through a computer network.
      A meeting of the AGO science team was held at San Fransisco in U.S.A.on February 6 and 7 to discuss the future plan of the AGO project, and Hiroshi Fukunishi and Yukihiro Takahashi attended the meeting from Japan. Deployment and redeployment of AGOs in the 1994/95 season, current status of the AGO database, and preliminary results of AGO science instruments were reported. They agreed on publishing a science report on early results of the AGO project.
      Summary plots of the search coil data taken in the first year of AGO-2 operation were made by the Japanese group. For several interesting events, enlarged plots to see fine structures and dynamic spectra by MEM were calculated, and Pc 1 and 2 pulsations were found around noon during magnetically quiet periods.
      Dr.C.G.Maclennan of AT&T Bell Laboratories was invited to Tohoku University from March 8 through 19 to analyze the search coil and fluxagate magnetometer data and to discuss the magnetic disturbances observed by the AGOs in the polar cap region.

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    • 北極域におけるオゾンおよび関連微量成分の研究観測

      日本学術振興会  科学研究費助成事業 

      岡野 章一, HARTWING Ger, 矢島 信之, 中島 英彰, 田口 真, 福西 浩

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      1993 - 1994

      Grant number:05041051

      Grant amount:\5000000 ( Direct Cost: \5000000 )

      1.1993年度は、実験の面からは北極域の成層圏上部のオゾン高度分布の観測を目的として、帰休に搭載してハートレー帯のオゾンによる太陽紫外線吸収を測定する光学オゾンセンサーの開発を重点的に行った。また北極域でのオゾン気球観測の準備としてスウェーデン・キルナのエスレンジ実験場等の事前調査を行うとともに、フランス・国立科学研究センター・超高層物理学研究所を訪問してヨーロッパ北極域でのオゾン観測についての情報交換、打合せを行った。この事前調査では2名を派遣した。
      2.1994年度には気球搭載の光学オゾンセンサーに以下のような改良を加えた。1993年度の光学センサーでは、気球の姿勢変化に補正するための紫外と可視の信号の除算をセンサー上で行い除算結果を地上に送信していたが、1994年度は同時に測定した紫外と可視の信号をそれぞれ地上に送信し、データ解析時に除算を行うようにした。また1993年度は296nmと305nmの2波長の紫外光強度を測定するために紫外と補正用可視フォトメータ対を2体搭載していたところを、1994年度は302nmの1対のみとし、低コスト化と軽量化を達成した。
      3.1994年7月23日と7月27日の2回にわたってノルウェー領スピッツベルゲン島ニ-オルソンにおいて、宇宙科学研究所気球工学部門、ドイツ・アルフレッドウェーゲナー極地海洋研究所およびノルウェー極地研究所の協力のもとに、BT-5型高々度気球(5000m^3)に光学オゾンセンサーを搭載して、北極域夏季の成層圏オゾン高度分布を調べるための放球観測を行った。なお、この放球観測では通常の電気化学式オゾンゾンデも同時に搭載して比較観測を行った。この放球観測では観測人員4名を現地に派遣した。
      4.1995年3月にスウェーデン・キルナのエスレンジ実験場において大気球に電気化学式オゾンゾンデ、化学蛍光法によるNOおよびNO_yセンサー、さらにエアロゾルカウンターを搭載して、北極域晩冬季の成層圏オゾンおよび窒素酸化物の高度分布の観測を行った。この観測では観測人員1名を現地に派遣した。
      5.北極域でのオゾン観測結果についての検討を以下のように行った。但し1995年3月のキルナでの気球禁則については本研究概要記入の段階でまだデータ管理が完了していないのでここでは割愛する。
      (1)スピッツベルゲンでの光学オゾンセンサーと電気化学式オゾンゾンデの同時観測結果を比較すると、高度25km以上では電気化学式オゾンゾンデは高度が高くなるにつれてオゾン数密度の観測値がほぼ単調に減少しているが、一方光学オゾンセンサーの観測結果は高度変化に対してオゾン数密度の高度分布に数kmのスケールの構造が現れている。高度25km以下では両者とも2回の観測で高度分布はよく一致している。特に高度10〜13kmにおけるオゾン数密度の7月23日と7月27日の違いが光学オゾンセンサーにも電気化学式オゾンゾンデにも同様に現れている。
      (2)国内で宇宙科学研究所の三陸大気球観測所で1994年5月と8月(中緯度夏季)に行った光学オゾンセンサーによるオゾン高度分布の観測結果とスピッツベルゲンでの観測結果(北極域夏季)を比較すると、高緯度の方がオゾン数密度のピークが現れる高度が低いという傾向が見られる。
      (3)スピッツベルゲンでの7月23日の光学オゾンセンサーと電気化学式オゾンゾンデとの同時観測では、光学オゾンセンサーの方がオゾン密度の変動に対して早く応答しているように見える。
      以上をまとめると、本研究において高々度気球搭載の光学オゾンセンサーにより北極圏の成層圏上部までのオゾン高度分布を十分な高度分解能で求めることが可能となった。

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    • レーザーヘテロダイン分光法によるメタン及び一酸化二窒素の季節変動の研究

      日本学術振興会  科学研究費助成事業 

      田口 真

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      4 1992 - 3 1993

      Authorship:Principal investigator  Grant type:Competitive

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    • Development of portable-type laser heterodyne spectrometer for the observation of the ozone hole

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      FUKUNISHI Hiroshi, TAGUCHI Makoto, OKANO Shoichi

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      1992 - 1993

      Grant number:04554014

      Grant amount:\15600000 ( Direct Cost: \15600000 )

      The portable-type laser heterodyne spectrometer was designed in 1992 and its construction was completed in 1993. It is equipped with four tunable diode lasers for measurements of various trace gases in the wavelength region of 8-11 mu m. The weight of the optics is 70 kg. The fine adjustment of the optics is easier than the former type and the laser instability due to optical feedback is reduced. This spectrometer has realized an extremely high wavenumber resolution of 0.0013 cm^<-1> and a high signal-to-noise ratio (typically 1500 for O_3 and 500 for N_2O) for each spectrum measured every 10 minutes. These characteristics enable us to derive the altitude profiles of atmospheric minor gases in the troposphere and stratosphere from observated spectra. Many observations were performed using this portable-type laser heterodyne spectrometer. The vertical profiles of ozone, nitrous oxide, and methane were observed at Tsukuba and Sendai. In 1994, similar observations were carried out at Syowa station, Antarctica. In 1996 and 1997, observations of ozone, nitrous oxide, and methane were performed for the validation of RIS and ILAS instruments on board the ADEOS satellite. Thus, important information on the ozone depletion processes was obtained using the portable-type laser heterodyne spectrometer developed in this study.

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    • 大気光多波長イメージング観測による中層大気波動現象の研究

      日本学術振興会  科学研究費助成事業 

      岡野 章一, 田口 真

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      1992 - 1992

      Grant number:04640422

      Grant amount:\2200000 ( Direct Cost: \2200000 )

      昨年度に製作した多波長全天撮像装置については、イメージインテンシファイアー直前の結像レンズのピント位置が、観測波長によって微妙に異なるという問題があることがわかっていた。昨年度まではその調整をマイクロメータを使用して手動で行っていたが、本年度、ステッピングモーターを組み込んでピント調整を自動化した。これによって観測開始から終了まで完全自動観測が可能となり、観測効率が向上するとともに観測モードの選択の自由度も増した。
      蛍光シートを貼った半球プラスチックドームと標準光源を用いて、観測毎に装置の絶対キャリブレーションと感度むら補正を行った。その結果装置の視野全体にわたって絶対値測定の精度が向上した。特にOH大気光の観測からOHの回転温度を導出するためには、この絶対値キャリブレーションは不可欠であり、今回の改良がOHの回転温度の導出を成功に導いた。
      このような改良を施した多波長全天撮像装置を使用して酸素原子557.7nm及び630.0nm、OH大気光の観測を東北大学蔵王観測所において実施した。酵素原子630.0nmの観測からは地磁気活動の活発化に呼応して電離層を伝播する擾乱(TID)や大気重力波に伴う増光が捉えられた。またOH大気光の観測からは回転線の強度化の温度依存性を利用して、OH(8-3)バンド回転温度の2次元分布の時間変動を導出することに成功した。

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    • Optical Study on the Upper Atmospheric Equatorial Anomaly

      Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research 

      OGAWA Toshihiro, KIYAMA Yoshitaka, TAGUCHI Makoto, OKANO Shyoichi, FUKUNISHI Hiroshi, KITA Kazuyuki, IWAGAMI Naomoto

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      1992 - 1992

      Grant number:04041121

      This research is to implement one of the projects of Solar-Terrestrial Energy Program (STEP) in Japan. Japanese STEP projects include a research area entitled "Energy and Dynamics of Coupled Ionosphere-Thermosphere System", in which the equatorial anomaly of the ionospheric F-region is one of the interesting topics. The equatorial anomaly is characterized by anomalously high electron densities in the zones of geomagnetic latitudes *15゚. It is a quasi-permanent structure and is created as a consequence of the coupled plasma motion due to plasma drift and ambipolar diffusion in the ionospheric electric field and in the geomagnetic field. Electron density in the equatorial anomaly exhibits a highly variable structure in space and time. Depletion of plasma occurs along the geomagnetic field lines, forming a non-linear stripe pattern in the direction rectangular to the field lines. Yet we have not fully understood the dynamical behavior of the F-region plasma in the equatorial anomaly and the origin of the wave disturbance.
      This research uses an optical sensing technique to measure the red line of atomic oxygen that is excited through the dissociative recombination of molecular oxygen ions and electrons. With this technique we can deduce a fine structure of the F-region electron density and the thermospheric wind system. The objective of this research is to illustrate the growth process of plasma instability in the F-region and to seek its excitation mechanism.
      Two observation sites were selected according to logistics conveniency and cloud condition of the sky. One is Mount Haleakala located in the north zone of the equatorial anomaly. The other is Watukosek in East Java and is located in the south zone of the equatorial anomaly, where our group is making a collaborative observation for atmospheric ozone and airglow with Indonesian Space Agency(LAPAN).
      Three scientists from our group stayed at Mt.Haleakala during 7 February - 7 March 1993 to make the airglow observation. The instruments used were an airglow photometer of rapid sky-scanning, a monochromatic all-sky imager and an imaging Fabry-Perot interferometer for atomic oxygen red line. We obtained the all-sky distributions of airglow intensity for atomic oxygen red line and other emission lines along with the Doppler temperature and shift of atomic oxygen red line. These data are useful to analyze the dynamics on the horizontal structure of the F-region plasma and to analyze temperature and wind system of the thermosphere.
      Visit to Watukosek was made during 25 November - 6 December 1992 to repair and overhaul the airglow photometer that was already set up there. We have asked the LAPAN scientists to continue the airglow observation using that photometer.

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