Researcher Database

Kiyoshi Kuramoto
Faculty of Science Earth and Planetary Sciences Cosmosciences
Professor

Researcher Profile and Settings

Affiliation

  • Faculty of Science Earth and Planetary Sciences Cosmosciences

Job Title

  • Professor

Degree

  • Ph.D(The University of Tokyo)
  • Master of Science(The University of Tokyo)

URL

J-Global ID

Research Interests

  • 物質進化   起源   地球   惑星   システム   現象   構造   進化   起源   惑星大気   システム   現象   構造   進化   起源   地球   惑星   System   Phenomena   Structure   Evolution   Origin   Earth   Planets   System   Phenomena   Structure   Evolution   Origin   Earth   Planets   System   Phenomena   Structure   Evolution   Origin   Earth   Planets   

Research Areas

  • Natural sciences / Astronomy
  • Natural sciences / Space and planetary science
  • Natural sciences / Solid earth science
  • Natural sciences / Atmospheric and hydrospheric science
  • Natural sciences / Solid earth science

Academic & Professional Experience

  • 2015/04 - Today Hokkaido University Division of Earth and Planetary Sciences, Faculty of Science Professor
  • 2007/04 - 2015/03 Hokkaido University Division of Natural History Sciences, Faculty of Science Professor
  • 2012/08 - 2014/07 Ministry of Education,Culture,Sports,Science and Technology
  • 2006/04 - 2007/03 Hokkaido University Division of Natural History Sciences, Faculty of Science Associate Professor
  • 2001/04 - 2006/03 Hokkaido University Department of Earth and Planetary Sciences, Graduate Scool of ScienceGraduate School of Science Associate Professor
  • 1998/11 - 2001/03 Hokkaido Univeristy Department of Earth and Plantary Sciences, Graduate School of Science Research Associate
  • 1997/04 - 1998/10 Hokkaido University Institute of Low Temperature Sciences Post doctoral fellowships of JSPS
  • 1995/09 - 1997/03 University of Tokyo Center for Climate System Research COE researcher
  • 1994/08 - 1995/08 Tokyo Institute of Technology Undergraduate School of Science Technical Assistant

Education

  •        - 1994  The University of Tokyo  Graduate School of Science
  •        - 1994  The University of Tokyo  Graduate School, Division of Science
  •        - 1991  The University of Tokyo  Graduate School of Science
  •        - 1991  The University of Tokyo  Graduate School, Division of Science
  •        - 1989  The University of Tokyo  Faculty of Science
  •        - 1989  The University of Tokyo  Faculty of Science

Association Memberships

  • 日本地球惑星科学連合   日本惑星科学会   

Research Activities

Published Papers

  • Shunichi Kamata, Francis Nimmo, Yasuhito Sekine, Kiyoshi Kuramoto, Naoki Noguchi, Jun Kimura, Atsushi Tani
    Nature Geoscience 12 (6) 407 - 410 1752-0894 2019/06/20 [Refereed][Not invited]
  • Takashi Ito, Masateru Ishiguro, Tomoko Arai, Masataka Imai, Tomohiko Sekiguchi, Yoonsoo P. Bach, Yuna G. Kwon, Masanori Kobayashi, Ryo Ishimaru, Hiroyuki Naito, Makoto Watanabe, Kiyoshi Kuramoto
    ature Communications 9 (2486) 2486  2041-1723 2018/06/27 [Refereed][Not invited]
  • Hiroaki Saito, Kiyoshi Kuramoto
    Monthly Notices of the Royal Astronomical Society Oxford University Press ({OUP}) 475 (1) 1274 - 1287 0035-8711 2018/03 [Refereed][Not invited]
  • Saito H, Kuramoto K
    Planetary People - The Japanese Society for Planetary Sciences 日本惑星科学会 27 (3) 229 - 234 0918-273X 2018 [Not refereed][Not invited]
     
    <p>形成期の惑星内部に取り込まれた初生水の D/H 比は地球と火星で異なるらしい.始原マントルにソースを持つと考えられる噴出岩中のメルト包有物中の H2O は,地球試料においては,星雲ガスを取り込んだことを示唆する低い D/H 比を示す一方で,火星試料においては,炭素質コンドライトに近い D/H 比を示す.両者の D/H 比の差異は,星雲内で集積する原始惑星上における原始大気の構造が惑星質量に依存しているためであるかもしれない.新たな一次元大気構造数値モデリングの結果によれば, 火星質量程度の原始惑星の場合,上層に星雲ガス成分,下層に衝突脱ガス成分からなる成層した混成型原始大気が形成し,接している原始マントルは材料物質に含まれる H2O の D/H 比を獲得することができる.これに対して,火星質量以上の原始惑星の場合,対流により起源の異なる両成分が混合し,下層大気の D/H 比は星雲ガスの値に接近する.これによって大質量の惑星の始原マントルは,星雲ガスに近い値の D/H 比を獲得できた可能性がある.</p>
  • Kuramoto K, Morota T, Nagaoka H, Nakagawa H, Nakamura T, Ogawa K, Otake H, Ozaki M, Sasaki S, Senshu H, Tachibana S, Kawakatsu Y, Terada N, Usui T, Wada K, Watanabe S, MMX study team, Fujimoto M, Genda H, Hirata N, Imamura T, Kameda S, Matsumoto K, Miyamoto H
    Planetary People - The Japanese Society for Planetary Sciences 日本惑星科学会 27 (3) 207 - 215 0918-273X 2018 [Not refereed][Not invited]
     
    <p>火星衛星Phobosからのサンプルリターンに挑む火星衛星探査計画 (Martian Moons eXploration: MMX) は,現在,宇宙航空研究開発機構 (JAXA) プリプロジェクトとして,2024年の打ち上げと5年の往還期間を設定し,精力的な検討・初期開発が進められている.MMXは,サンプル分析,Deimosを加えた火星衛星の近接観測,そして火星大気および火星圏のモニタリング観測を組み合わせることにより,惑星に寄りそう衛星という切り口と視座から,太陽系における大気と水を湛えたハビタブル惑星の形成と進化の解明に迫ろうとしている.</p>
  • Daisuke Kuroda, Masateru Ishiguro, Makoto Watanabe, Sunao Hasegawa, Tomohiko Sekiguchi, Hiroyuki Naito, Fumihiko Usui, Masataka Imai, Mitsuteru Sato, Kiyoshi Kuramoto
    Astronomy & Astrophysics {EDP} Sciences 611 0004-6361 2017/11 [Refereed][Not invited]
  • Masateru Ishiguro, Daisuke Kuroda, Makoto Watanabe, Yoonsoo P. Bach, Jooyeon Kim, Mingyeong Lee, Tomohiko Sekiguchi, Hiroyuki Naito, Katsuhito Ohtsuka, Hidekazu Hanayama, Sunao Hasegawa, Fumihiko Usui, Seitaro Urakawa, Masataka Imai, Mitsuteru Sato, Kiyoshi Kuramoto
    ASTRONOMICAL JOURNAL 154 (5) 180  0004-6256 2017/11 [Refereed][Not invited]
     
    We conducted a polarimetric observation of the fast-rotating near-Earth asteroid (1566) Icarus at large phase (Sun-asteroid-observer's) angles alpha = 57 degrees-141 degrees around the 2015 summer solstice. We found that the maximum values of the linear polarization degree are P-max = 7.32 +/- 0.25% at phase angles of alpha(max) = 124 degrees +/- 8 degrees in the V-band and P-max = 7.04 +/- 0.21% at alpha(max) = 124 degrees +/- 6 degrees in the RC-band. Applying the polarimetric slope-albedo empirical law, we derived a geometric albedo of p(V) = 0.25 +/- 0.02, which is in agreement with that of Q-type taxonomic asteroids. amax is unambiguously larger than that of Mercury, the Moon, and another near-Earth S-type asteroid (4179) Toutatis but consistent with laboratory samples with hundreds of microns in size. The combination of the maximum polarization degree and the geometric albedo is in accordance with terrestrial rocks with a diameter of several hundreds of micrometers. The photometric function indicates a large macroscopic roughness. We hypothesize that the unique environment (i.e., the small perihelion distance q = 0.187 au and a short rotational period of T-rot = 2.27 hr) may be attributed to the paucity of small grains on the surface, as indicated on (3200) Phaethon.
  • S. Noda, M. Ishiwatari, K. Nakajima, Y. O. Takahashi, S. Takehiro, M. Onishi, G. L. Hashimoto, K. Kuramoto, Y. -Y. Hayashi
    ICARUS 282 1 - 18 0019-1035 2017/01 [Refereed][Not invited]
     
    In order to investigate a possible variety of atmospheric states realized on a synchronously rotating aqua planet, an experiment studying the impact of planetary rotation rate is performed using an atmospheric general circulation model (GCM) with simplified hydrological and radiative processes. The entire planetary surface is covered with a swamp ocean. The value of planetary rotation rate is varied from zero to the Earth's, while other parameters such as planetary radius, mean molecular weight and total mass of atmospheric dry components, and solar constant are set to the present Earth's values. The integration results show that the atmosphere reaches statistically equilibrium states for all runs; none of the calculated cases exemplifies the runaway greenhouse state. The circulation patterns obtained are classified into four types: Type-I characterized by the dominance of a day-night thermally direct circulation, Type-II characterized by a zonal wave number one resonant Rossby wave over a meridionally broad westerly jet on the equator, Type-III characterized by a long time scale north-south asymmetric variation, and Type-IV characterized by a pair of mid-latitude westerly jets. With the increase of planetary rotation rate, the circulation evolves from Type-I to Type-II and then to Type-III gradually and smoothly, whereas the change from Type-Ill to Type-IV is abrupt and discontinuous. Over a finite range of planetary rotation rate, both Types-III and -IV emerge as statistically steady states, constituting multiple equilibria. In spite of the substantial changes in circulation, the net energy transport from the day side to the night side remains almost insensitive to planetary rotation rate, although the partition into dry static energy and latent heat energy transports changes. The reason for this notable insensitivity is that the outgoing longwave radiation over the broad area of the day side is constrained by the radiation limit of a moist atmosphere, so that the transport to the night side, which is determined as the difference between the incoming solar radiation and the radiation limit, cannot change greatly. (C) 2016 The Authors. Published by Elsevier Inc.
  • Mission concept of Martian moons eXploration (MMX)
    Y. Kawakatsu, K. Kuramoto, N. Ogawa, H. Ikeda, Y. Mimasu, G. One, H. Sawada, K. Yoshikawa, Takane Imada, Hisashi Otake, H. Kusano, K. Yamada, M. Otsuki, M. Baba
    Proceedings in the 68th International Astronautical Congress 2017 [Refereed][Not invited]
  • Kamata, Shunichi, Kimura, Jun, Matsumoto, Koji, Nimmo, Francis, Kuramoto, Kiyoshi, Namiki, Noriyuki
    Journal of Geophysical Research-Planets 121 (7) 1362 - 1375 2169-9097 2016 [Refereed][Not invited]
  • Yasufumi Iryu, Kiyoshi Kuramoto, Masaki Satoh, Jun Matsumoto, Shoichi Yoshioka, Hodaka Kawahata, Ryuji Tada
    PROGRESS IN EARTH AND PLANETARY SCIENCE 3 (1) 2197-4284 2016/01 [Refereed][Not invited]
  • Kamata, Shunichi, Kimura, Jun, Matsumoto, Koji, Nimmo, Francis, Kuramoto, Kiyoshi, Namiki, Noriyuki
    Journal of Geophysical Research-Planets 121 (7) 1362  2169-9097 2016 [Refereed][Not invited]
  • Kamata Shunichi, Sugita Seiji, Abe Yutaka, Ishihara Yoshiaki, Harada Yuji, Morota Tomokatsu, Namiki Noriyuki, Iwata Takahiro, Hanada Hideo, Araki Hiroshi, Matsumoto Koji, Tajika Eiichi, Kuramoto Kiyoshi, Nimmo Francis
    ICARUS 250 492 - 503 0019-1035 2015/04 [Refereed][Not invited]
  • K. Sugiyama, K. Sugiyama, K. Sugiyama, K. Nakajima, M. Odaka, K. Kuramoto, K. Kuramoto, Y. Y. Hayashi, Y. Y. Hayashi
    Icarus 231 407 - 408 0019-1035 2014/03/01 [Refereed][Not invited]
  • K. Sugiyama, K. Nakajima, M. Odaka, K. Kuramoto, Y. -Y. Hayashi
    ICARUS 229 71 - 91 0019-1035 2014/02 [Refereed][Not invited]
     
    A series of long-term numerical simulations of moist convection in Jupiter's atmosphere is performed in order to investigate the idealized characteristics of the vertical structure of multi-composition clouds and the convective motions associated with them, varying the deep abundances of condensable gases and the autoconversion time scale, the latter being one of the most questionable parameters in cloud microphysical parameterization. The simulations are conducted using a two-dimensional cloud resolving model that explicitly represents the convective motion and microphysics of the three cloud components, H2O, NH3, and NH4SH imposing a body cooling that substitutes the net radiative cooling. The results are qualitatively similar to those reported in Sugiyama et al. (Sugiyama, K. et al. [2011]. Intermittent cumulonimbus activity breaking the three-layer cloud structure of Jupiter. Geophys. Res. Lett. 38, L13201. doi:10.1029/2011GL047878): stable layers associated with condensation and chemical reaction act as effective dynamical and compositional boundaries, intense cumulonimbus clouds develop with distinct temporal intermittency, and the active transport associated with these clouds results in the establishment of mean vertical profiles of condensates and condensable gases that are distinctly different from the hitherto accepted three-layered structure (e.g., Atreya, S.K., Romani, P.N. [1985]. Photochemistry and clouds of Jupiter, Saturn and Uranus. In: Recent Advances in Planetary Meteorology. Cambridge Univ. Press, London, pp. 17-68). Our results also demonstrate that the period of intermittent cloud activity is roughly proportional to the deep abundance of H2O gas. The autoconversion time scale does not strongly affect the results, except for the vertical profiles of the condensates. Changing the autoconversion time scale by a factor of 100 changes the intermittency period by a factor of less than two, although it causes a dramatic increase in the amount of condensates in the upper troposphere. The moist convection layer becomes potentially unstable with respect to an air parcel rising from below the H2O lifting condensation level (LCL) well before the development of cumulonimbus clouds. The instability accumulates until an appropriate trigger is provided by the H2O condensate that falls down through the H2O LCL; the H2O condensate drives a downward flow below the H2O LCL as a result of the latent cooling associated with the re-evaporation of the condensate, and the returning updrafts carry moist air from below to the moist convection layer. Active cloud development is terminated when the instability is completely exhausted. The period of intermittency is roughly equal to the time obtained by dividing the mean temperature increase, which is caused by active cumulonimbus development, by the body cooling rate. 2013 The Authors. Published by Elsevier Inc. All rights reserved.
  • Tsumura, K., Arimatsu, K., Egami, E., Hayano, Y., Honda, C., Kimura, J., Kuramoto, K., Matsuura, S., Minowa, Y., Nakajima, K., Nakamoto, T., Shirahata, M., Surace, J., Takahashi, Y., Wada, T.
    Astrophysical Journal 789 (2) 0004-637X 2014 [Refereed][Not invited]
     
    Based on observations from the Hubble Space Telescope and the Subaru Telescope, we have discovered that Europa, Ganymede, and Callisto are bright around 1.5 μm even when not directly lit by sunlight. The observations were conducted with non-sidereal tracking on Jupiter outside of the field of view to reduce the stray light subtraction uncertainty due to the close proximity of Jupiter. Their eclipsed luminosity was 10 -6 -10 -7 of their uneclipsed brightness, which is low enough that this phenomenon has been undiscovered until now. In addition, Europa in eclipse was < 1/10 of the others at 1.5 μm, a potential clue to the origin of the source of luminosity. Likewise, Ganymede observations were attempted at 3.6 μm by the Spitzer Space Telesc ope, but it was not detected, suggesting a significant wavelength dependence. It is still unknown why they are luminous even when in the Jovian shadow, but forward-scattered sunlight by hazes in the Jovian upper atmosphere is proposed as the most plausible candidate. If this is the case, observations of these Galilean satellites while eclipsed by the Jovian shadow provide us with a new technique to investigate the Jovian atmospheric composition. Investigating the transmission spectrum of Jupiter by this method is important for investigating the atmosphere of extrasolar giant planets by transit spectroscopy. © 2014. The American Astronomical Society. All rights reserved.
  • Kiyoshi Kuramoto, Takafumi Umemoto, Masaki Ishiwatari
    EARTH AND PLANETARY SCIENCE LETTERS 375 312 - 318 0012-821X 2013/08 [Refereed][Not invited]
     
    Hydrodynamic escape of hydrogen driven by solar extreme ultraviolet (EUV) radiation heating is numerically simulated by using the constrained interpolation profile scheme, a high-accuracy scheme for solving the one-dimensional advection equation. For a wide range of hydrogen number densities at the lower boundary and solar EUV fluxes, more than half of EUV heating energy is converted to mechanical energy of the escaping hydrogen. Less energy is lost by downward thermal conduction even giving low temperature for the atmospheric base. This result differs from a previous numerical simulation study that yielded much lower escape rates by employing another scheme in which relatively strong numerical diffusion is implemented. Because the solar EUV heating effectively induces hydrogen escape, the hydrogen mixing ratio was likely to have remained lower than 1 vol% in the anoxic Earth atmosphere during the Archean era. (C) 2013 Elsevier B.V. All rights reserved.
  • K. Sugiyama, A. Suzuki, J. Takahashi, T. Nakamura, S. Manabe, authors
    Planetary People 21 (4) 368 - 376 0918-273X 2012/12 [Refereed][Not invited]
  • Y. Sekine, Y. Takano, H. Yano, authors
    Planetary People 21 (3) 229 - 238 0918-273X 2012/09 [Refereed][Not invited]
  • Atmospheric structure and cloud convection in Jupiter's atmosphere
    K. Sugiyama, K. Nakajima, M. Odaka, M. Ishiwatari, K. Kuramoto, Y. O. Takahashi, Y.-Y. Hayashi
    Planetary People 21 (1) 39 - 44 2012/03 [Refereed][Not invited]
  • Youhei Sasaki, Shin-ichi Takehiro, Kiyoshi Kuramoto, Yoshi-Yuki Hayashi
    PHYSICS OF THE EARTH AND PLANETARY INTERIORS 188 (3-4) 203 - 213 0031-9201 2011/10 [Refereed][Not invited]
     
    Numerical experiments are performed in order to investigate an MHD dynamo in a rotating spherical shell with stress-free top and no-slip bottom boundaries. The Ekman number, the Prandtl number, and the ratio of inner to outer radii are fixed as 10(-3), 1, and 0.35, respectively. The magnetic Prandtl number is varied from 5 to 50, and the modified Rayleigh number is increased from 1.5 to 10 times the critical Rayleigh number. The initial imposed magnetic field is either a weak or strong magnetic field, where the magnetic energy of the initial field is approximately two orders of magnitude smaller or larger than the kinetic energy of the quasi-steady state of non-magnetic thermal convection. For cases involving a weak initial magnetic field, self-sustained dynamo solutions are established when the magnetic Prandtl number is larger than or equal to 5, and the modified Rayleigh number is larger than or equal to 5 times the critical Rayleigh number. The solutions are categorized as a weak field-dynamo, where the mean magnetic energy is one order of magnitude smaller than the mean kinetic energy. The dynamo solutions are characterized by a radially two-layer spatial structure. The upper layer is dominated by a strong prograde zonal mean zonal flow with large-scale prograde propagating spiral vortices having a longitudinal wavenumber of 3. Toroidal kinetic energy is converted to toroidal magnetic energy through stretching of the field lines by large-scale prograde propagating spiral vortices. On the other hand, the lower layer contains small-scale retrograde propagating columnar convective vortices having a longitudinal wavenumber of 8. The magnetic field lines are not concentrated in the vortices, but rather wind around the vortices in each layer. Poloidal kinetic energy is converted to poloidal magnetic energy through winding of the field lines around small-scale retrograde propagating columnar convective vortices. For cases involving a strong initial magnetic field, self-sustained dynamo solutions are established when the magnetic Prandtl number is greater than or equal to 4 and the modified Rayleigh number is greater than or equal to 3 times the critical Rayleigh number. In contrast with the cases involving a weak initial magnetic field, all of the dynamo solutions are strong-field solutions. Bistability is observed when the magnetic Prandtl number is 5, and the modified Rayleigh number is approximately equal to 10 times the critical Rayleigh number, where weak-field and strong-field dynamo solutions coexist. However, transition between the weak-field and strong-field solutions does not occur in this case. (C) 2011 Elsevier B.V. All rights reserved.
  • K. Sugiyama, K. Nakajima, M. Odaka, M. Ishiwatari, K. Kuramoto, Y. Morikawa, S. Nishizawa, Y. O. Takahashi, Y-Y. Hayashi
    GEOPHYSICAL RESEARCH LETTERS 38 (13) L13201, 5 PP., 2011 doi:10.1029/2011GL047878  0094-8276 2011/07 [Refereed][Not invited]
     
    A long-term numerical simulation is performed to investigate idealized characteristics of the cloud layer of Jupiter's atmosphere using a two-dimensional cloud convection model that treats thermodynamics and microphysics of the three cloud components, H(2)O, NH(3), and NH(4)SH. A prominent result obtained is intermittent emergence of vigorous cumulonimbus clouds rising from the H(2)O condensation level to the tropopause. Due to the active transport associated with these clouds, the mean vertical distributions of cloud particles and condensible gases are distinctly different from the hitherto accepted three-layered structure; considerable amounts of H(2)O and NH(4)SH cloud particles exist above the NH(3) condensation level, while the mixing ratios of all condensible gases decrease with height from the H(2)O condensation level. The mean vertical profile of NH(3) vapor is consistent with the results of radio observations in that the abundance of NH(3) is subsolar below the NH(3) cloud base. Citation: Sugiyama, K., K. Nakajima, M. Odaka, M. Ishiwatari, K. Kuramoto, Y. Morikawa, S. Nishizawa, Y. O. Takahashi, and Y.-Y. Hayashi (2011), Intermittent cumulonimbus activity breaking the three-layer cloud structure of Jupiter, Geophys. Res. Lett., 38, L13201, doi: 10.1029/2011GL047878.
  • Kimura, Jun, Kawamura, Taichi, Morito, Hisataka, Morota, Tomokatsu, Honda, Chikatoshi, Kuramoto, Kiyoshi, Okada, Tatsuaki
    Icarus 214 (2) 596 - 605 0019-1035 2011 [Refereed][Not invited]
  • 倉本 圭, 阿部 豊, はしもと じょーじ, 林 祥介, 関根 康人, 佐藤 光輝
    天文月報 日本天文学会 102 (3) 184 - 189 0374-2466 2009/02/20 [Not refereed][Not invited]
  • Exploring the Martian meteorology and hydrology(Definition of Science Objectives for MELOS Mars Exploration)
    今村 剛, 笠井 康子, 佐川 英夫, 黒田 剛史, 佐藤 毅彦, 上野 宗孝, 鈴木 睦, 高橋 幸弘, 高橋 芳幸, はしもと じょーじ, 倉本 圭
    Planetary People 日本惑星科学会 18 76 - 78 2009 [Not refereed][Not invited]
     
    火星表層の水循環や気象学の理解を目的とする火星周回衛星の検討を進めている.可視〜赤外域での高解像度の分光撮像による水蒸気マッピングと大気力学場モニター,そしてサブミリ波サウンダーによる水蒸気やその他微量ガスの3次元分布の観測が,二つの柱である.着陸機による局地気象の直接観測や大気電気観測との連携についても検討中である.
  • Global material transport in the solar nebula controlled by ice component
    Low Temperature Science 66 83 - 88 2008 [Not refereed][Not invited]
  • 氷が担う原始太陽系星雲のグローバル物質輸送
    低温科学 66 83 - 88 2008 [Not refereed][Not invited]
  • Young Edward D, Kuramoto Kiyoshi, Marcus Rudolph A, Yurimoto Hisayoshi, Jacobsen Stein B
    Reviews in Mineralogy and Geochemistry Mineralogical Society of America 68 (1) 187 - 218 2008 [Refereed][Not invited]
  • Collaboration Between University and Public Observatory Based on a Broadband Network
    杉山 耕一朗, 小高 正嗣, 佐野 康男, 大石 憲且, 馬場 聡, 高井 昌彰, 大石 尊久, 林 祥介, 倉本 圭, 渡部 重十
    Planetary People 日本惑星科学会 17 123 - 129 2008 [Not refereed][Not invited]
     
    北海道大学と名寄市立木原天文台とを接続する広帯域ネットワークを構築し,研究と教育の連携のための実験を行った.広帯域ネットワークを用いる最大の利点は,地理的に離れた両拠点の既存の機材とソフトウェア環境を現地まで移動することなく相互に利用できるようになり,両拠点が一体の遠隔天文台として機能できることである.実際に,北海道大学から木原天文台の望遠鏡を遠隔操作して天体の操像観測を試み,遠隔天文台としての機能の検証を行った.また,両拠点の観望映像のどちらか条件の良い映像をインターネット中継映像として配信する実験を行い,今回我々の構築したネットワーク環境が天文現象のインターネット中継の成功率向上に資することを確認した.
  • Fukui Takashi, Kuramoto Kiyoshi
    ORIGIN OF MATTER AND EVOLUTION OF GALAXIES AIP 1016 409 - 411 0094-243X 2008 [Refereed][Not invited]
  • Kuramoto Kiyoshi, Genda Hidenori, Arai Tomoko, Okada Tatsuaki, Sugita Seiji
    Planetary People 日本惑星科学会 16 (3) 197 - 207 0918-273X 2007/09/25 [Not refereed][Not invited]
     
    惑星内部の進化の実証的研究は惑星科学の萌芽的分野であり,「かぐや」をはじめとする月の新たな探査はその前進のための大きな一歩となる.本論文では,これまでの月内部進化についての理解とそれにまっわる謎について,月の熱進化の観点からレビューする.そして今後どのような着眼点で何を調べると月内部進化の理解に有益なのか,考えるためのヒントを提供したい.
  • Naoya Sakamoto, Yusuke Seto, Shoichi Itoh, Kiyoshi Kuramoto, Kiyoshi Fujino, Kazuhide Nagashima, Alexander N Krot, Hisayoshi Yurimoto
    Science (New York, N.Y.) 317 (5835) 231 - 3 0036-8075 2007/07/13 [Refereed][Not invited]
     
    Oxygen isotopic composition of our solar system is believed to have resulted from mixing of two isotopically distinct nebular reservoirs, 16O-rich and (17,18)O-rich relative to Earth. The nature and composition of the (17,18)O-rich reservoir are poorly constrained. We report an in situ discovery of a chemically and isotopically unique material distributed ubiquitously in fine-grained matrix of a primitive carbonaceous chondrite Acfer 094. This material formed by oxidation of Fe,Ni-metal and sulfides by water either in the solar nebula or on a planetesimal. Oxygen isotopic composition of this material indicates that the water was highly enriched in 17O and 18O (delta(17,18)O(SMOW) = +180 per thousand per mil), providing the first evidence for an extremely (17,18)O-rich reservoir in the early solar system.
  • Yurimoto Hisayoshi, Kuramoto Kiyoshi, Krot Alexander N, Scott Edward RD, Cuzzi Jeffrey N, Thiemens Mark H, Lyons James R
    Protostars and planets V Citeseer 849 - 862 2007 [Refereed][Not invited]
  • K Sugiyama, M Odaka, K Kuramoto, YY Hayashi
    GEOPHYSICAL RESEARCH LETTERS 33 (3) L03201 - L03201 0094-8276 2006/02 [Refereed][Not invited]
     
    The dependency of static stability N-2 of the Jovian atmospheres on the abundances of condensible elements is considered by calculating the moist adiabatic profiles. An optimal minimization method of the Gibbs free energy is utilized to obtain equilibrium compositions in order to cover a variety of basic elements. It is shown that CH4 is one of the dominant contributors to producing a stable layer in the Uranian atmosphere. On Jupiter, R. K. Achterberg and A. P. Ingersoll (1989) have shown that, at low water abundances, N-2 is proportional to the H2O abundance. In the present study, we show that this relationship does not hold when the H2O abundance is larger than approximately 5 x solar. A rough estimation of wave speed indicates that the abundance of 10 x solar is marginal to explain the SL9-induced wave speed as that of an internal gravity wave.
  • K Sugiyama, M Odaka, K Kuramoto, YY Hayashi
    GEOPHYSICAL RESEARCH LETTERS 33 (3) 0094-8276 2006/02 [Refereed][Not invited]
     
    The dependency of static stability N-2 of the Jovian atmospheres on the abundances of condensible elements is considered by calculating the moist adiabatic profiles. An optimal minimization method of the Gibbs free energy is utilized to obtain equilibrium compositions in order to cover a variety of basic elements. It is shown that CH4 is one of the dominant contributors to producing a stable layer in the Uranian atmosphere. On Jupiter, R. K. Achterberg and A. P. Ingersoll (1989) have shown that, at low water abundances, N-2 is proportional to the H2O abundance. In the present study, we show that this relationship does not hold when the H2O abundance is larger than approximately 5 x solar. A rough estimation of wave speed indicates that the abundance of 10 x solar is marginal to explain the SL9-induced wave speed as that of an internal gravity wave.
  • KURAMOTO Kiyoshi, YURIMOTO Hisayoshi
    Planetary people 日本惑星科学会 14 (4) 193 - 200 0918-273X 2005/12/25 [Not refereed][Not invited]
  • Kuramoto Kiyohi, Yurimoto Hisayoshi
    Chondrites and the Protoplanetary Disk 341 181 - 192 2005 [Refereed][Not invited]
  • Hisayoshi Yurimoto, Kiyoshi Kuramoto
    Science (New York, N.Y.) 305 (5691) 1763 - 6 0036-8075 2004/09/17 [Refereed][Not invited]
     
    Meteorites and their components have anomalous oxygen isotopic compositions characterized by large variations in 18O/16O and 17O/16O ratios. On the basis of recent observations of star-forming regions and models of accreting protoplanetary disks, we suggest that these variations may originate in a parent molecular cloud by ultraviolet photodissociation processes. Materials with anomalous isotopic compositions were then transported into the solar nebula by icy dust grains during the collapse of the cloud. The icy dust grains drifted toward the Sun in the disk, and their subsequent evaporation resulted in the 17O- and 18O-enrichment of the inner disk gas.
  • Nakagami Yuuichi, Ohshima Osamu, Sugiyama Ko-ichiro, Kawabata Yoshihito, Sato Koichiro, Kobayashi Kazumasa, Sasagawa Hirotatsu, Odaka Msatusgu, Kuramoto Kiyoshi, Mosir project Mosir project
    Planetary People 日本惑星科学会 12 (2) 80 - 88 0918-273X 2003/06/25 [Not refereed][Not invited]
  • T Yokohata, M Odaka, K Kuramoto
    ICARUS 159 (2) 439 - 448 0019-1035 2002/10 [Refereed][Not invited]
     
    In order to study the stability of martian climate, we constructed a two-dimensional (horizontal-vertical) energy balance model. The long-term CO2 mass exchange process between the atmosphere and CO2 ice caps is investigated with particular attention to the effect of planetary ice distribution on the climate stability. Our model calculation suggests that high atmospheric pressure presumed for past Mars would be unstabilized if H2O ice widely prevailed. As a result, a cold climate state might have been achieved by the condensation of atmospheric CO2 onto ice caps. On the other hand, the low atmospheric pressure, which is buffered by the CO2 ice cap and likely close to the present pressure, would be unstabilized if the CO2 ice albedo decreased. This may have led the climate into a warm state with high atmospheric pressure owing to complete evaporation of CO2 ice cap. Through the albedo feedback mechanisms of H2O and CO2 ices in the atmosphere-ice cap system, Mars may have experienced warm and cold climates episodically in its history. (C) 2002 Elsevier Science (USA).
  • Hiroki Senshu, Kiyoshi Kuramoto, Takafumi Matsui
    Journal of Geophysical Research: Planets Wiley-Blackwell 107 (E12) 5118  0148-0227 2002 [Refereed][Not invited]
  • YOKOHATA, KURAMOTO Kiyoshi
    Planetary People 日本惑星科学会 10 (2) 64 - 74 0918-273X 2001/06/25 [Not refereed][Not invited]
  • Climate changes on Mars: CO2 polar cap and H2O ice sheet
    10 64 - 74 2001 [Not refereed][Not invited]
  • SENSHU Hiroki, KURAMOTO Kiyoshi, MATSUI Takafumi
    Planetary People 日本惑星科学会 9 (1) 17 - 32 0918-273X 2000/03/25 [Not refereed][Not invited]
  • Early thermal history of a proto-planet
    9 17 - 32 2000 [Not refereed][Not invited]
  • The ocean in Europa
    47 39 - 40 2000 [Not refereed][Not invited]
  • エウロパの海
    天気 (日本気象学会誌) 47 39 - 40 2000 [Not refereed][Not invited]
  • 倉本 圭
    号外地球 海洋出版 25 - 29 0916-9733 1999/02 [Not refereed][Not invited]
  • Feasibility of exploration of lunar iron core
    7 218 - 220 1998 [Not refereed][Not invited]
  • 鉄のコアの観測可能性
    遊・星・人 (日本惑星科学会誌) 7 218 - 220 1998 [Not refereed][Not invited]
  • Kuramoto Kiyoshi, Saiganji Yoshihiko, Yamamoto Tetsuo
    Lunar and Planetary Science Conference 29 1998 [Refereed][Not invited]
  • KURAMOTO Kei
    Planetary People 日本惑星科学会 6 (3) 196 - 198 0918-273X 1997/09/25 [Not refereed][Not invited]
  • Kiyoshi Kuramoto
    Physics of the Earth and Planetary Interiors Elsevier {BV} 100 (1-4) 3  0031-9201 1997/03 [Refereed][Not invited]
  • Special issue, Origin and evolution of the Moon
    6 196 - 198 1997 [Not refereed][Not invited]
  • KURAMOTO K
    Physics of Earth and Planetary Interiors 100 (1/4) 3 - 20 0031-9201 1997 [Not refereed][Not invited]
  • Kiyoshi Kuramoto, Takafumi Matsui
    Journal of Geophysical Research: Planets Wiley-Blackwell 101 (E6) 14909  0148-0227 1996/06 [Refereed][Not invited]
  • 倉本 圭, 松井 孝典
    科学 岩波書店 66 (3) 193 - 201 0022-7625 1996/03 [Not refereed][Not invited]
  • KURAMOTO K, MATSUI T
    Journal of Geophysical Research 101 (E6) 14909 - 14932 0148-0227 1996 [Not refereed][Not invited]
  • KURAMOTO Kiyoshi
    Planetary People 日本惑星科学会 4 (4) 201 - 214 0918-273X 1995/12/25 [Not refereed][Not invited]
  • Earth and Mars: H, C, and early differentiation
    4 201 - 214 1995 [Not refereed][Not invited]
  • KURAMOTO K, MATSUI T
    Journal of Geophysical Research 99 (E10) 21183 - 21200 0148-0227 1994 [Not refereed][Not invited]
  • Kiyoshi Kuramoto, Takafumi Matsui
    Journal of Geophysical Research Wiley-Blackwell 99 (E10) 21183  0148-0227 1994 [Refereed][Not invited]

Books etc

  • 在田 一則, 池田 元美, 倉本 圭, 小笹 隆司, 佐藤 光輝, 沢田 健, 白岩 孝行, 杉山 慎, 鈴木 徳行, 高波 鐵夫, 竹下 徹, 谷岡 勇一郎, 池田 隆司, 谷本 陽一, 知北 和久, 角皆 潤, 永井 隆哉, 中川 光弘, 新井田 清信, 長谷部 文雄 (Joint work)
    北海道大学出版会 2010/11 (ISBN: 4832981951) 427
  • 沢田 健, 西 弘嗣, 栃内 新, 馬渡 峻輔, 綿貫 豊, 秋元 信一, 阿波根 直一, 大原 昌宏, 柁原 宏, 片倉 春雄, 倉本 圭, 小林 快次, 鈴木 徳行, 高橋 英樹, 堀口 健雄, 前川 光司, 増田 道夫, 増田 隆一, 沢田 健, 西 弘嗣, 馬渡 峻輔, 綿貫 豊 (Joint work)
    北海道大学図書刊行会 2008/03 (ISBN: 4832981838) 272

MISC

Awards & Honors

  • 2005 日本気象学会 堀内賞
     地球および惑星における主要親気性元素の挙動に関する理論的研究 
    受賞者: 倉本 圭
  • 2005 2005, Horiuchi Prize, Meteorological Society of Japan

Research Grants & Projects

  • 文部科学省:科学研究費補助金(新学術領域研究(研究領域提案型), 新学術領域研究(研究領域提案型))
    Date (from‐to) : 2011 -2015 
    Author : 倉本 圭, 阿部 豊, 林 祥介, はしもと じょーじ, 関根 康人
     
    [循環シミュレーション]太陽系惑星とは諸条件の異なる系外惑星へ適用するための大気循環数値シミュレーションの基幹部となる力学計算コードの新開発に着手した。その開発版を用いて小質量星周りのハビタブルゾーンに多数存在することが期待される同期回転惑星を題材とした三次元大気シミュレーションを行い、新たな水循環レジームを見出すなどの成果を得た。また鉛直水平二次元系で木星型惑星大気の雲対流の計算を進め、凝結性成分の鉛直分布が、一般によく用いられてきた熱平衡モデルと大幅に異なることを見出した。これは観測量の解釈に大きな影響を持つ。[大気進化理論]表層のH20量と中心星放射の違いによって、地球型惑星が大きく異なる表層環境を持つと予想し、地球型惑星の新分類を提起した。観測の進展が期待されるスーパーアースについては、ハビタブルゾーン内に存在する場合は全球海洋で覆われた海惑星である可能性が高い。また天体衝突現象に関連した大気形成と初期進化モデルを提起した。とくに地球型惑星形成の最終段階で期待される巨大衝突後の高温水蒸気大気の進化について、惑星が暴走温室限界を超える中心星放射を受ける場合には大気散逸過程が惑星の冷却率をコントロールする。初期の水量や惑星質量によっては十億年以上の時間スケールでマグマオーシャンを有する状態が持続する可能性があり、これは将来の観測研究への新予想である。[特徴推定]系外惑星大...
  • 文部科学省:科学研究費補助金(基盤研究(C), 基盤研究(C))
    Date (from‐to) : 2010 -2012 
    Author : 倉本 圭
     
    1.マントルオーバーターンの理論解析月のマグマオーシャンの結晶分化過程とマントルオーバーターンが理想的に進んだものと仮定して、それが月の慣性能率に及ぼす影響を推算した。その結果、月の慣性能率の観測値が持つ均質球からの偏差が、月に金属核を置くことなくマントルオーバーターンのみによってもおおよそ説明可能であることが分かった。この見積もりはマントルオーバーターンによる月内部の安定成層の最大値を与えて評価しており、より現実性のある見積もりを行うには、その後の月マントルの進化によって成層がどの程度破壊される可能性があるか追及する必要がある。2.流体数値シミュレーションマントルオーバーターン現象ならびにその後のマントル進化をシミュレートすることを目的に、水星を念頭に置いた流体数値モデルを用いたテスト計算を行った。組成一様、放射性熱源なしの条件で粘性率の比較的高い状態から出発してシミュレーションを行ったところ、水星のマントルは10億年のタイムスケールで急激に冷却し、粘性率の増加と相まって、温度分布は静止系の熱伝導解に漸近することが分かった。これは対流過程による熱輸送を、混合距離理論によって表現した球対称モデル計算と調和的であった。3.月の火成活動・分化の地質記録サーベイ理論的解析と比較する目的で、最近進展の著しい月マントルの進化についての地質学的研究のサーベイを行い、火成活動の開始と活動期...
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(C))
    Date (from‐to) : 2007 -2009 
    Author : Kiyoshi KURAMOTO, Youhei SASAKI, Takashi FUKUI, Tomoko IWAHORI
     
    The bulk composition of Mercury estimated from a model for the solar nebula evolution is adopted for the numerical and theoretical analysis of the thermal history and dynamo action of this innermost planet. The mantle components are probably more viscous than the previous estimates, which slows down the growth of solid inner core. The release of light element from the slowly growing inner core possibly induces the convection of outer liquid core with generating a moderate dynamo action and the present weak intrinsic magnetic field. These results provide a basis for the interpretation of dat...
  • 文部科学省:科学研究費補助金(若手研究(B))
    Date (from‐to) : 2004 -2006 
    Author : 倉本 圭
     
    古火星に想定される高圧の二酸化炭素大気の鉛直一次元大気熱収支・放射対流平衡モデルの開発は,多方向・高波長分解計算の厳密化,ならびに,散乱温室効果をもたらす二酸化炭素氷雲の鉛直プロファイル決定機構の導入を行い,ほぼ満足のできるレベルに到達した.このモデルを用いて,古火星大気の放射対流平衡構造・熱収支・二酸化氷雲による温室効果についての境界条件を変化させたパラメタスタディを進め,3気圧以上の大気圧と10^5-10^7kg^<-1>の範囲の凝結核混合比があれば,38億年前の火星において全球平均気温がH_2Oの融点を超える温暖な気候が実現されることが分かった.一方,凝結核混合比が極めて小さい,あるいは大きい場合には,大気圧を増加させてゆくと,やがては地表面へのCO_2凝結が起こり,いわゆる大気崩壊が起こることがわかった.地球大気を参考にすると凝結核混合比は数桁の範囲で変動することが予想される.温室効果の強さが凝結核混合比に強く依存することは,火星の高クレーター密度地域の地形侵食が著しくは進んでいない,つまり温暖湿潤な気候の出現が間欠的であったと示唆されるここと調和する.大気の地表面への凝結によって形成される二酸化炭素氷床の流動過程について,その数値計算のための流動則と涵養消耗過程についての基礎的な定式化を行った。完成した大気放射モデルから凝結核の挙動が重要なことが判明し,凝結核の移流...
  • 文部科学省:科学研究費補助金(奨励研究(A))
    Date (from‐to) : 1999 -2000 
    Author : 倉本 圭
     
    集積期の火星熱史について現実的な微惑星サイズ分布を与えた数値シミュレーションを行うと同時に,火星CO_2大気-極冠システムの安定性解析を行った.熱史の数値シミュレーションから得られた結果は以下の通りである.1)火星半径が約3000kmに達すると微惑星衝突点の融解が起こり始める.2)融解開始後,半径がさらに300km成長するまで,サイズの大きな微惑星のみが融解に寄与する.以上の結果は,火星の大気,マントル,金属核の分化が集積過程の末期に起こり始めることを意味する.火星において実現し得る大気状態を明らかにするには,大気-極冠システムの安定性の解析が必要である.そのために大気-極冠間の質量交換を考慮した2次元エネルギーバランスモデルを構築した.このモデルは,与えられた日射の緯度分布に対し,大気-地表システムのエネルギー・質量バランスの南北・鉛直構造を解くものである.そこにはCO_2大気の温室効果,緯度間の熱輸送,地表-大気間の熱およびCO_2交換(極冠における凝縮,蒸発)過程が組み込まれている.このモデルを用いた安定性解析の結果を以下に説明する.大気-極冠システムが長期的な定常状態にあるためには,火星年で積分したCO_2凝結量と蒸発量が釣り合った状態になければならない.それには,大気圧が低く大部分のCO_2が極冠に凝結した"冷たい"定常状態と,極冠が完全に蒸発し大気圧が高い"熱い"...
  • Material evolution from interstellar clouds to planetary systems
    Date (from‐to) : 1993
  • Planetary surface environment
    Date (from‐to) : 1988
  • Formation and evolution of the Earth and planets
    Date (from‐to) : 1988

Educational Activities

Teaching Experience

  • Special Lecture of Cosmosciences 1
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 理学院
    キーワード : 惑星科学、天文学、地球物理学
  • Special Lecture of Cosmosciences 1
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 理学院
    キーワード : 飛翔体技術,飛翔体観測,惑星探査,天文衛星
  • Special Lecture of Cosmosciences 2
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 理学院
    キーワード : 惑星科学、天文学、地球物理学
  • Special Lecture of Cosmosciences 2
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 理学院
    キーワード : 飛翔体技術,飛翔体観測,惑星探査,天文衛星
  • Advanced Course on Planetary Systems 1
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 理学院
    キーワード : 比較惑星学、地球、月、地球型惑星、木星型惑星、氷衛星、太陽系小天体、系外惑星
  • Basic Earth and Planetary Science Ⅱ
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 宇宙,惑星,大気と海洋の運動と構造,気候変動,地球環境
  • Physics for Planetary Atmosphere
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 地球惑星大気、放射、静水圧平衡、熱力学、気体分子運動論、物質循環、エネルギー収支、大気の起源と進化、系外惑星
  • Exercises in Information Sciences
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 計算機ネットワーク、計算機、基本作法、基礎技術、情報科学、地球惑星情報学


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