5:15 PM - 6:30 PM
[ACG38-P04] Observing system simulation experiments for new satellite observation missions on Venus
Keywords:Venus atmosphere, Data assimilation, Observing system simulation experiment
Observation system simulation experiment (OSSE) is a method for testing a virtual observation system using a data assimilation method, which enables us to evaluate planned observation by reproducibility of a target phenomenon. On Earth, it is actively used for objective evaluation of meteorological forecasting skill when new observations, such as satellite observations, are introduced (e.g., Masutani et al., 2010) 1. However, there are few examples of OSSE for planetary satellite observation missions. Since a planetary satellite mission is limited in time and resources, it would be quite useful to investigate its effectiveness by using OSSE in advance to optimize its instruments and observation plans.
To implement OSSE, we need both a data assimilation system and a reliable meteorological model which can reproduce the atmospheric phenomena realistically. We have developed “AFES-Venus” (Sugimoto et al., 2014a) 2 which is based on AFES (Atmospheric GCM For the Earth Simulator) optimized for the Earth simulator, and “ALEDAS-V” (AFES LETKF Data Assimilation System for Venus) (Sugimoto et al., 2017) 3 which is the first data assimilation system for the Venus atmosphere using AFES-Venus and Local Ensemble Transform Kalman Filter (LETKF). In this presentation, we show an overview of four OSSEs conducted by this assimilation system (Table).
The radio occultation measurements mission between multiple small satellites is expected as a method to observe the vertical temperature distribution at altitudes in about 40-90km penetrating a thick cloud cover at altitudes in about 48–70 km. In addition, the observation frequency and coverage would be significantly improved compared to the radio occultation between the Earth and satellites. In this study, OSSE was performed for the observation points by actual orbit calculation4, and the effectiveness of the orbit was investigated from (1) the reproducibility of “cold collar”5,6 and (2) the improvement of the speed of “super rotation”, which are notable atmospheric phenomena on Venus.
Observations of the Venus Orbiter "Akatsuki" provide us horizontal distributions of the horizontal wind derived from cloud tracking of the UVI camera and of temperature observed by the LIR camera. In this study, the observational limits of Akatsuki were reduced, and OSSE was performed for various observation coverages (day and night side, or latitude area) and observation frequencies, and the effectiveness of the observations was investigated from (3) the reproducibility of “planetary-scale equatorial Kelvin waves with 4-day period” 7 and (4) the improvement of phases of “thermal tides”.
[1] Masutani, M., J. S. Woollen, S. J. Lord, G. D. Emmitt, T. J. Kleespies, S. A. Wood, S. Greco, H. Sun, J. Terry, V. Kapoor, R. Treadon, and K. A. Campana (2010), J. Geophys. Res., 115.
[2] Sugimoto, N., M. Takagi, and Y. Matsuda (2014a), J. Geophys. Res. Planets, 119, 1950–1968.
[3] Sugimoto, N., A. Yamazaki, T. Kouyama, H. Kashimura, T. Enomoto, and M. Takagi (2017), Scientific Reports, 7(1), 9321.
[4] Yamamoto, T., S. Ikari, H. Ando, T. Imamura, A. Hosono, M. Abe, Y. Fujisawa, N. Sugimoto, Y. Kawabata, R. Funase, and S. Nakasuka, (2021), Journal of the Japan Society for Aeronautical and Space Sciences, submitted.
[5] Sugimoto, N., M. Abe, Y. Kikuchi, A. Hosono, H. Ando, M. Takagi, I. Garate-Lopez, S. Lebonnois, and C. Ao (2019b), Journal of Japan Society of Civil Engineers A2: Applied Mechanics, 75(2), 477–486.
[6] Fujisawa, Y., N. Sugimoto, C. Ao, A. Hosono, H. Ando, M. Takagi, I. Garate-Lopez and S. Lebonnois, in preparation.
[7] Sugimoto, N., Y. Fujisawa, M. Shirasaka, A. Hosono, M. Abe, H. Ando, M. Takagi, M. Yamamoto, (2021), Atmosphere, Vol.12, No.1, 14, 16pp.
To implement OSSE, we need both a data assimilation system and a reliable meteorological model which can reproduce the atmospheric phenomena realistically. We have developed “AFES-Venus” (Sugimoto et al., 2014a) 2 which is based on AFES (Atmospheric GCM For the Earth Simulator) optimized for the Earth simulator, and “ALEDAS-V” (AFES LETKF Data Assimilation System for Venus) (Sugimoto et al., 2017) 3 which is the first data assimilation system for the Venus atmosphere using AFES-Venus and Local Ensemble Transform Kalman Filter (LETKF). In this presentation, we show an overview of four OSSEs conducted by this assimilation system (Table).
The radio occultation measurements mission between multiple small satellites is expected as a method to observe the vertical temperature distribution at altitudes in about 40-90km penetrating a thick cloud cover at altitudes in about 48–70 km. In addition, the observation frequency and coverage would be significantly improved compared to the radio occultation between the Earth and satellites. In this study, OSSE was performed for the observation points by actual orbit calculation4, and the effectiveness of the orbit was investigated from (1) the reproducibility of “cold collar”5,6 and (2) the improvement of the speed of “super rotation”, which are notable atmospheric phenomena on Venus.
Observations of the Venus Orbiter "Akatsuki" provide us horizontal distributions of the horizontal wind derived from cloud tracking of the UVI camera and of temperature observed by the LIR camera. In this study, the observational limits of Akatsuki were reduced, and OSSE was performed for various observation coverages (day and night side, or latitude area) and observation frequencies, and the effectiveness of the observations was investigated from (3) the reproducibility of “planetary-scale equatorial Kelvin waves with 4-day period” 7 and (4) the improvement of phases of “thermal tides”.
[1] Masutani, M., J. S. Woollen, S. J. Lord, G. D. Emmitt, T. J. Kleespies, S. A. Wood, S. Greco, H. Sun, J. Terry, V. Kapoor, R. Treadon, and K. A. Campana (2010), J. Geophys. Res., 115.
[2] Sugimoto, N., M. Takagi, and Y. Matsuda (2014a), J. Geophys. Res. Planets, 119, 1950–1968.
[3] Sugimoto, N., A. Yamazaki, T. Kouyama, H. Kashimura, T. Enomoto, and M. Takagi (2017), Scientific Reports, 7(1), 9321.
[4] Yamamoto, T., S. Ikari, H. Ando, T. Imamura, A. Hosono, M. Abe, Y. Fujisawa, N. Sugimoto, Y. Kawabata, R. Funase, and S. Nakasuka, (2021), Journal of the Japan Society for Aeronautical and Space Sciences, submitted.
[5] Sugimoto, N., M. Abe, Y. Kikuchi, A. Hosono, H. Ando, M. Takagi, I. Garate-Lopez, S. Lebonnois, and C. Ao (2019b), Journal of Japan Society of Civil Engineers A2: Applied Mechanics, 75(2), 477–486.
[6] Fujisawa, Y., N. Sugimoto, C. Ao, A. Hosono, H. Ando, M. Takagi, I. Garate-Lopez and S. Lebonnois, in preparation.
[7] Sugimoto, N., Y. Fujisawa, M. Shirasaka, A. Hosono, M. Abe, H. Ando, M. Takagi, M. Yamamoto, (2021), Atmosphere, Vol.12, No.1, 14, 16pp.