[PPS06-P12] Trials toward first Venus analysis product by data assimilation of Akatsuki observation
Keywords:Akatsuki, Venus atmosphere, Data assimilation
The model used in this study is a Venusian GCM (AFES-Venus) and the Venus AFES LETKF Data Assimilation System (ALEDAS-V) based on the Local Ensemble Transform Kalman Filter (LETKF) that has been developed for the first time1. Using ALEDAS-V, we have examined impact of data assimilation on thermal tides for the Venus Express wind observations2. In addition, we have examined the reproducibility of a unique atmospheric structure so-called “cold collar”, a cold latitudinal band encircling the warm polar vortex at about 60–70 km altitudes, in order to elucidate the effects of fixed temperature observations by multiple small satellites3.
In this presentation, we will introduce results obtained for idealized data assimilation. One is for vertical profiles of temperature assuming radio occultation observation with realistic trajectory (Related to Hosono et al.4). The other is for distributions of horizontal wind assuming camera observation (Related to Fujisawa et al.5). These are necessary attempts before assimilating actual observation data. Furthermore, we will also introduce the results of assimilating actual Akatsuki observation data.
 Development of an ensemble Kalman filter data assimilation system for the Venusian atmosphere, N. Sugimoto, A. Yamazaki, T. Kouyama, H. Kashimura, T. Enomoto, and M. Takagi, Scientific Reports, Vol. 7, (2017), 9321, 9pp.
 Impact of data assimilation on thermal tides in the case of Venus Express wind observation, N. Sugimoto, T. Kouyama, and M. Takagi, Geophys. Res., Lett., Vol. 46, (2019), pp. 4573–4580.
 Observing system simulation experiment for radio occultation measurements of the Venus atmosphere among small satellites, N. Sugimoto, M. Abe, Y. Kikuchi, A. Hosono, H. Ando, M. Takagi, I. Garate-Lopez, S. Lebonnois and C. Ao, Journal of Japan Society of Civil Engineers A2: Applied Mechanics, Vol. 75, No.2, (2019), pp. I_477-I_486.
 The study for designing the future Venus atmosphere observing mission of radio occultation measurement among small satellites using data assimilation, A. Hosono, Y. Fujisawa, N. Sugimoto, M. Abe, Y. Kikuchi, T. Yamamoto, Y. Kawabata, S. Ikari, H. Ando, M. Takagi, I. G. Lopez, S. Lebonnois, C. Ao, JpGU, (2020), A-OS21.
 Data Assimilation of the Venus Atmosphere to Reproduce Planetary-scale Wave, Y. Fujisawa, M. Shirasaka, N. Sugimoto, A. Hosono, M. Abe, H. Ando, M. Takagi, and M. Yamamoto, JpGU, (2020), A-OS21.