金星探査機と地上観測の連携による金星大気の物質循環の解明

2019 Fiscal Year Annual Research Report

• Project/Area Number: 16H02231
• Research Institution: Japan Aerospace EXploration Agency
• Principal Investigator: 中村 正人 国立研究開発法人宇宙航空研究開発機構, 宇宙科学研究所, 教授 (20227937)
• Co-Investigator(Kenkyū-buntansha): 高木 征弘 京都産業大学, 理学部, 教授 (00323494) ; 前澤 裕之 大阪府立大学, 理学(系)研究科(研究院), 准教授 (00377780) ; はしもと じょーじ 岡山大学, 自然科学研究科, 教授 (10372658) ; 中川 広務 東北大学, 理学研究科, 助教 (30463772) ; 今村 剛 東京大学, 大学院新領域創成科学研究科, 教授 (40311170) ; 佐川 英夫 京都産業大学, 理学部, 教授 (40526034) ; 堀之内 武 北海道大学, 地球環境科学研究院, 教授 (50314266) ; 田口 真 立教大学, 理学部, 教授 (70236404) ; 林 祥介 神戸大学, 理学研究科, 教授 (20180979)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 金星 / 探査 / あかつき / 大気

Outline of Annual Research Achievements

金星にどのような大気循環が存在し、それがどのようにして雲形成に関わる物質循環をもたらすのかを、探査機「あかつき」と地上望遠鏡による協調観測、および数値モデリングによって解明してきた。これまでの金星大気研究で行われてきた紫外画像を用いた雲追跡に加え、全ローカルタイムをカバーする赤外画像での雲追跡を新たな画像解析手法により実現することにより、平均子午面循環の構造を明らかにするとともに、高速帯状流に関わる可能性のある様々な惑星規模波動の特徴を明らかにした。惑星規模の大気波動の一種である熱潮汐波が引き起こす角運動量輸送が高速帯状風の維持に関わることの観測的手がかりを得るとともに、数値モデリングによって観測結果を裏付けることができた。観測データと数値モデリングを統合するにあたっては、金星で初めてデータ同化を試みて、モデル内の大気構造の改善に成功した。メソスケールでは、地形励起重力波の詳細な全球分布を雲画像解析により明らかにし、また鉛直伝播する重力波とそれが生成する乱流層の分布を電波掩蔽データから明らかにした。また電波掩蔽観測によって雲層の上下にわたる全球的な温度構造を初めて精密観測し、極域の下層大気に成層の弱い領域が存在するなど、未知の熱輸送プロセスの存在を示唆する結果を得た。こうした観測結果をもとに大気大循環モデルに雲物理過程を導入し、観測結果と整合的な硫酸雲の分布を再現し、雲形成における大気力学の役割の理解を進めることができた。さらに、平均風速、惑星規模波動の活動度、雲の紫外アルベドの長期変化を明らかにして、これらの相互作用による気候変動に迫ることができた。

Research Progress Status

令和元年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

令和元年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] NASA(米国)
  • Country Name: U.S.A.
  • Counterpart Institution: NASA
• [Int'l Joint Research] ケルン大学(ドイツ)
  • Country Name: GERMANY
  • Counterpart Institution: ケルン大学
• [Int'l Joint Research] LMD(フランス)
  • Country Name: FRANCE
  • Counterpart Institution: LMD
• [Journal Article] Dynamical effect on static stability of the Venus atmosphere simulated using a general circulation model: a comparison with radio occultation measurements (2022)
  • Author(s): H. Ando, K. Takaya, M. Takagi, N. Sugimoto, T. Imamura, H. Sagawa, S. Tellmann, M.Patsold, Y.Matsuda, B.Hausler, S.Limaye,R.K.Choudhary, M.Antonita
  • Journal Title: J. Geophys. Res Volume: 127 Pages: -
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Characteristic features of V0 layer in the Venus ionosphere as observed by the Akatsuki orbiter: evidence for its presence during the local noon and post-sunset conditions (2022)
  • Author(s): Keshav R. Tripathi, R. K. Choudhary, K.M. Ambili, T. Imamura, H. Ando
  • Journal Title: Geophys. Res. Lett. Volume: - Pages: -
  • DOI: 10.1029/2022GL097824
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Amateur Observers Witness the Return of Venus’ Cloud Discontinuity (2022)
  • Author(s): Emmanuel Kardasis, Javier Peralta, Grigoris Maravelias, Masataka Imai, Anthony Wesley, Tiziano Olivetti, Yaroslav Naryzhniy, Luigi Morrone, Antonio Gallardo, Giovanni Calapai, Joaquin Camarena, Paulo Casquinha, Dzmitry Kananovich, Niall MacNeill, Christian Viladrich, Alexia Takoudi
  • Journal Title: Atmosphere Volume: 13(2) Pages: -
  • DOI: 10.3390/atmos13020348
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Horizontal structures of bow-shaped mountain wave trains seen in thermal infrared images of Venusian clouds taken by Akatsuki LIR (2022)
  • Author(s): Kiichi Fukuya, Takeshi Imamura, Makoto Taguchi, Toru Kouyama
  • Journal Title: Icarus Volume: 378 Pages: -
  • DOI: 10.1016/j.icarus.2022.114936
  • Peer Reviewed
• [Journal Article] Dynamical Effect on Static Stability of the Venus Atmosphere Simulated Using a General Circulation Model: A Comparison With Radio Occultation Measurements (2022)
  • Author(s): Hiroki Ando, Koutarou Takaya, Masahiro Takagi, Norihiko Sugimoto, Takeshi Imamura, Hideo Sagawa, Silvia Tellmann, Martin Patzold, Yoshihisa Matsuda, Bernd Hausler, Sanjay Limaye, Raj Kumar Choudhary, Maria Antonita
  • Journal Title: J. Geophys. Res. Planets Volume: 127 Pages: -
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  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Planetary-Scale Waves Seen in Thermal Infrared Images of Venusian Cloud Top (2021)
  • Author(s): Naoya Kajiwara, Takeshi Imamura, Makoto Taguchi, Toru Kouyama
  • Journal Title: J.Geophys.Res.:Planets Volume: 126 Pages: -
  • DOI: 10.1029/2021JE007047
  • Peer Reviewed
• [Journal Article] Thermal tides in the upper cloud layer of Venus as deduced from the emission angle dependence of the brightness temperature by Akatsuki/LIR (2021)
  • Author(s): Masahiro Akiba, Makoto Taguchi, Tetsuya Fukuhara, Takeshi Imamura, Toru Kouyama, Takao M. Sato
  • Journal Title: J. Geophys. Res.: Planets Volume: 126 Pages: -
  • DOI: 10.1029/2020JE006808
  • Peer Reviewed
• [Journal Article] Gravity Wave Packets in the Venusian Atmosphere Observed by Radio Occultation Experiments: Comparison With Saturation Theory (2021)
  • Author(s): Ryota Mori, Takeshi Imamura, Hiroki Ando, Bernd Hausler, Martin Patzold, Silvia Tellmann
  • Journal Title: J. Geophys. Res.: Planets Volume: 126 Pages: -
  • DOI: 10.1029/2021JE006912
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Unveiling of nightside cloud-top circulation of Venus atmosphere (2021)
  • Author(s): 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
  • Journal Title: Nature Volume: 595 Pages: 511-515
  • DOI: 10.1038/s41586-021-03636-7
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Instrumental requirements for the study of Venus' cloud top using the UV imaging spectrometer VeSUV (2021)
  • Author(s): Emmanuel Marcq, Franck Montmessin, Jeremie Lasue, Bruno Bezard, Kandis L. Jessup, Yeon Joo Lee, Colin F.Wilson, Benjamin Lustrement, Nicolas Rouanet, Gabriel Guignan
  • Journal Title: Adv.Space Res. Volume: 68 Pages: 275-291
  • DOI: 10.1016/j.asr.2021.03.012
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Investigation of UV absorbers on Venus using the 283 and 365 nm phase curves obtained from Akatsuki (2021)
  • Author(s): Lee, Y. J., A. Garcia Munoz, A. Yamazaki, M. Yamada, S. Watanabe, T. Encrenaz
  • Journal Title: Geophysical Research Letters Volume: 48 Pages: -
  • DOI: 10.1029/2020GL090577
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] BepiColombo Science Investigations During Cruise and Flybys at the Earth, Venus and Mercury (2021)
  • Author(s): Mangano, V., Dosa, M., Franz, M., Milillo, A., Oliveira, J. S., Lee, Y. J, Slavin, J. A., Krger, H., Maturilli, A., Cornet, T., Iwai, K., Miyoshi, Y., Lucente, M., Massetti, S., Schmidt, C. A., Dong, C., McKnna-Lawlor, S., Grassi, D., Heyner, D., Kozyrev, A. S., Peron, R.
  • Journal Title: Space Sci. Rev. Volume: 217 Pages: -
  • DOI: 10.1007/s11214-021-00797-9
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Brightness modulations of our nearest terrestrial planet Venus reveal atmospheric super-rotation rather than surface features (2020)
  • Author(s): Lee, Y. J., A. Garcia Munoz, T. Imamura, M. Yamada, T. Satoh, A. Yamazaki, S. Watanabe
  • Journal Title: Nature Communications Volume: 11 Pages: -
  • DOI: 10.1038/s41467-020-19385-6
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Venus night-side photometry with "cleaned" Akatsuki/IR2 data: Aerosol properties and variations of carbon monoxide (2020)
  • Author(s): Takehiko Satoh, Choon Wei Vun, Masafumi Kimata, Takeshi Horinouchi, Takao M. Sato
  • Journal Title: Icarus Volume: 355 Pages: -
  • DOI: 10.1016/j.icarus.2020.114134
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Spatial and Temporal Variability of the 365-nm Albedo of Venus Observed by the Camera on Board Venus Express (2020)
  • Author(s): Lee, Y. J., P. Kopparla, J. Peralta, S. E. Schroder, T. Imamura, T. Kouyama, S. Watanabe
  • Journal Title: J. Geophys. Res.: Planets Volume: 125 Pages: -
  • DOI: 10.1029/2019JE006271
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] A Long-Lived Sharp Disruption on the Lower Clouds of Venus (2020)
  • Author(s): Peralta, J., T. Navarro, C. W. Vun, A. Sanchez-Lavega, K. McGouldrick, T. Horinouchi, T. Imamura, R. Hueso, J. P. Boyd, G. Schubert, T. Kouyama, T. Satoh, N. Iwagami, E. F. Young, M. A. Bullock, P. Machado, Y. J. Lee, S. S. Limaye, M. Nakamura, S. Tellmann, A. Wesley, P. Miles
  • Journal Title: Geophysical Research Letters, Volume: 47 Pages: -
  • DOI: 10.1029/2020GL087221
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] How waves and turbulence maintain the super-rotation of Venus’ atmosphere (2020)
  • Author(s): Horinouchi, T., Y.-Y. Hayashi, S. Watanabe, M Yamada, A. Yamazaki, T. Kouyama, M. Taguchi, T. Fukuhara, M. Takagi, K. Ogohara, S. Murakami, J. Peralta, S. S. Limaye, T. Imamura, M. Nakamura, T. M. Sato, T. Satoh
  • Journal Title: Science Volume: 368 Pages: 405-409
  • DOI: 10.1126/science.aaz4439
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Vertical coupling between the cloud-level atmosphere and the thermosphere of Venus inferred from the simultaneous observations by Hisaki and Akatsuki (2020)
  • Author(s): Nara. Y., T. Imamura, K. Masunaga, Y. J. Lee, N. Terada, K. Yoshioka, A. Yamazaki, K. Seki, I. Yoshikawa, M. Yamada, S. Watanabe
  • Journal Title: J. Geophys. Res.: Planets Volume: 125 Pages: -
  • DOI: 10.1029/2019JE006192
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Thermal structure of the Venusian atmosphere from the sub-cloud region to the mesosphere as observed by radio occultation (2020)
  • Author(s): Ando, H., T. Imamura, S. Tellmann, M. Patzold, B. Hausler, N. Sugimoto, M. Takagi, H. Sagawa, S. Limaye, Y. Matsuda, R. Kumar Choudhary, M. Antonita
  • Journal Title: Scientific Reports Volume: 10 Pages: -
  • DOI: 10.1038/s41598-020-59278-8
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Dayside cloud top structure of Venus retrieved from Akatsuki IR2 observations (2020)
  • Author(s): Sato, T. M., T. Satoh, H. Sagawa, N. Manago, Y. J. Lee, S. Murakami, K. Ogohara, G. L. Hashimoto, Y. Kasaba, A. Yamazaki, M. Yamada, S. Watanabe
  • Journal Title: Icarus Volume: 345 Pages: -
  • DOI: 10.1016/j.icarus.2020.113682
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] A recharge oscillator model for interannual variavility in Venus'clouds (2020)
  • Author(s): Kopparla, P., A. Seshadri, T. Imamura, Y. J. Lee
  • Journal Title: J. Geophys. Res.: Planets Volume: 125 Pages: -
  • DOI: 10.1029/2020JE006568
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Planetary-scale variations in winds and UV brightness at the Venusian cloud top: Periodicity and temporal evolution (2019)
  • Author(s): Imai, M., T. Kouyama, Y. Takahashi, A. Yamazaki, S. Watanabe, M. Yamada, T. Imamura, T. Satoh, M. Nakamura, S. Murakami, K. Ogohara, T. Horinouchi
  • Journal Title: J. Geophys. Res.:Planets Volume: 124 Pages: -
  • DOI: 10.1029/2019JE006065
  • Peer Reviewed / Open Access
• [Journal Article] Long-term Variations of Venus's 365 nm Albedo Observed by Venus Express, Akatsuki, MESSENGER, and the Hubble Space Telescope (2019)
  • Author(s): Lee, Y.-J., K.-L. Jessup, S. Perez-Hoyos, D. V. Titov, S. Lebonnois, J. Peralta, T. Horinouchi, T. Imamura, S. Limaye, E. Marcq, M. Takagi, A. Yamazaki, M. Yamada, S. Watanabe, S. Murakami, K. Ogohara, W. M. McClintock, G. Holsclaw, A. Roman
  • Journal Title: AJ Volume: 158 Pages: -
  • DOI: 10.3847/1538-3881/ab3120
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Venus' cloud top wind study: coordinated Akatsuki/UVI with cloud tracking and TNG/HARPS-N with Doppler velocimetry observations, Icarus (2019)
  • Author(s): Gonsalves, R., P. Machado, T. Widemann, J. Peralta, S. Watanabe, A. Yamazaki, T. Satoh, M Takagi, K. Ogohara, Y.-J. Lee, A Harutyunyan, J. Silva
  • Journal Title: Icarus Volume: 335 Pages: -
  • DOI: 10.1016/j.icarus.2019.113418
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Global structure of thermal tides in the upper cloud layer of Venus revealed by LIR onboard Akatsuki (2019)
  • Author(s): Kouyama, T., 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
  • Journal Title: Geophys. Res. Lett. Volume: 46 Pages: 9457-9465
  • DOI: 10.1029/2019GL083820
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Constraints on Venus Lightning from Akatsuki's first Three Years in Orbit (2019)
  • Author(s): Lorenz, R. D., M. Imai, Y. Takahashi, M. Sato, A. Yamazaki, T. M. Sato, T. Imamura, T. Satoh, M. Nakamura
  • Journal Title: Geophys. Res. Lett. Volume: 46 Pages: 7955-7961
  • DOI: 10.1029/2019GL083311
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Principal components of short-term variability in the ultraviolet albedo of Venus, (2019)
  • Author(s): Kopparla, P., Y.-J. Lee, T. Imamura, A. Yamazaki
  • Journal Title: A&A Volume: 626 Pages: -
  • DOI: 10.1051/0004-6361/201935388
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] New cloud morphologies discovered on the Venus's night during Akatsuki (2019)
  • Author(s): Peralta, J., A. Sanchez-Lavega, T. Horinouchi, K. McGouldrick, I. Garate-Lopez, E. F. Young, M. A. Bullock, Y.-J. Lee, T. Imamura, T. Satoh, S. S. Limaye
  • Journal Title: Icarus Volume: 333 Pages: 177-182
  • DOI: 10.1016/j.icarus.2019.05.026
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Stationary features at the cloud top of Venus observed by Ultraviolet Imager onboard Akatsuki (2019)
  • Author(s): Kitahara, T., T. Imamura, T. M. Sato, A. Yamazaki, Y.-J. Lee, M. Yamada, S. Watanabe, M. Taguchi, T. Fukuhara, T. Kouyama, S. Murakami, G. L. Hashimoto, K. Ogohara, H. Kashimura, T. Horinouchi, M. Takagi
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  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Influence of the cloud-level neutral layer on the vertical propagation of topographically generated gravity waves on Venus (2019)
  • Author(s): Yamada, T., T. Imamura, T. Fukuhara, M. Taguchi
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  • Peer Reviewed / Open Access
• [Journal Article] Impact of Data Assimilation on Thermal Tides in the Case of Venus Express Wind Observation (2019)
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  • Peer Reviewed
• [Journal Article] Formation of the Y feature at the Venusian cloud top by planetary-scale waves and the mean circulation: analysis of Venus Express VMC images (2019)
  • Author(s): Nara, Y., T. Imamura, S. Murakami, T. Kouyama, K. Ogohara, M. Yamada, M. Takagi, H. Kashimura, N. Sato
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  • Peer Reviewed