[P-PS05] Science of Venus: knowing more about the earth's sister planet

[PPS05-10] Mean winds and planetary-scale waves at the cloud top of Venus from the 6-year observation of Akatsuki/UVI

*Takeshi Horinouchi¹, Toru Kouyama², Masataka Imai³, Yeon Joo Lee⁴, Shin-ya Murakami⁵, Shigeto Watanabe⁶, Manabu Yamada⁷, Atsushi Yamazaki⁵ (1.Faculty of Environmental Earth Science, Hokkaido University, 2.AIST, 3.Kyoto Sangyo University, 4.Institute for Basic Science, 5.ISAS, 6.Hokkaido Information University, 7.Chiba Institute of Technology)

Keywords:Venus, Wind, Wave

Akasuki has been in operation since its orbital insertion in Dec 2015, and UVI onboard Akatsuki has been nearly continuously observing dayside UV radiance from around the cloud top. Horinouchi et al (2018) documented the mean winds and their variations obtained over the first ~1.5 years. Here, we update the study with the observation until 2021, and we further report long-term statistics of planetary-scale waves, updating the case study of Imai et al (2019). The topics include hemispheric asymmetry and its variability, long-term and low-frequency variations of the superrotation, thermal tides, and statistics of the Rossby and the equatorial Kelvin waves.

References:
Horinouchi, T., T. Kouyama, Y. J. Lee, S. Murakami, K. Ogohara, M. Takagi, T. Imamura,K. Nakajima, J. Peralta, A. Yamazaki, M. Yamada, and S. Watanabe (2018). Mean winds at the cloud top of Venus obtained from two-wavelength UV imaging by Akatsuki. Earth, Planets, Space, 70:10. https://doi.org/10.1186/s40623-017-0775-3

Imai, M., Kouyama, T., Takahashi, Y., Yamazaki, A., Watanabe, S., Yamada, M., Imamura, T., Satoh, T., Nakamura, M., Murakami, S., Ogohara, K., and Horinouchi, T. (2019). Planetary-scale variations in winds and UV brightness at the Venusian cloud top: Periodicity and temporal evolution. J. Geophys. Res.: Planets, 124(10), 2635-2659. https://doi.org/10.1029/2019JE006065