Research Field
Planetary atmosphere, Planetary exploration
Current Research
The circulation of energy and substances in a planetary atmosphere controls the development of the planetary environment, thereby governing the possibility of a biosphere. The planetary atmospheres observed so far show surprising diversity, whose origin is still unclear. Our laboratory focuses on planetary atmosphere physics and resultant climate formation. The ultimate goal is general understanding of common physical processes behind the apparent diversity.
The following observational and theoretical approaches are ongoing.
(1) Exploration of planetary atmospheres
Exploration of Venus atmosphere by a Japanese Venus explorer AKATSUKI is ongoing. We use AKATSUKI's data to unveil the mysteries of Venusian meteorology such as the high-speedwestward circulation "super-rotation" and thick sulfuric acid clouds. Development of a Mars exploration program including the studies of water cycle and dust transport is also ongoing.
(2) Radio occultation observations
In a radio occultation experiment, a spacecraft transmits radio waves toward a tracking station on the earth and sequentially goes behind the planet's atmosphere; during such occultation events the planetary atmosphere cause frequency and amplitude fluctuation, from which information on the atmosphere is obtained. We apply this technique to planets and the solar corona.
(3) Numerical modeling
Common physical processes behind the apparent diversity of atmospheric phenomena on the planets are investigated with numerical modeling and theories.
Representative Publications
1. Imamura,T., Mitchell, J., Lebonnois, S., Kaspi, Y., Showman, A.P., Korablev, O., Superrotation in planetary atmospheres. Space Sci. Rev., 216:87 (2020)
2. Imamura, T., Miyamoto, M., Ando, H., Häusler, B., Pätzold, M., Tellmann, S., Tsuda, T., Aoyama, Y., Murata, Y., Takeuchi, H., Yamazaki, A., Toda, T., Tomiki, A., (2018) Fine vertical structures at the cloud heights of Venus revealed by radio holographic analysis of Venus Express and Akatsuki radio occultation data. J. Geophys. Res., 123, 2151-2161.
3. Imamura, T., M. Tokumaru, H. Isobe, D. Shiota, H. Ando, M. Miyamoto, T. Toda, B. Häusler, M. Pätzold, A. Nabatov, A. Asai, K. Yaji, M. Yamada, M. Nakamura, Outflow structure of the quiet Sun corona probed by spacecraft radio scintillations in strong scattering, Astrophys. J., 788, 117(10pp), doi:10.1088/0004-637X/788/2/117, 2014.
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