Fujisawa Yukiko, Murakami Shin-Ya, Sugimoto Norihiko, Takagi Masahiro, Imamura Takeshi, Horinouchi Takeshi, Hashimoto George L, Ishiwatari Masaki, Enomoto Takeshi, Miyoshi Takemasa, Kashimura Hiroki, Hayashi Yoshi-Yuki
Research and Education Center for Natural Sciences, Keio University, 4-1-1, Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8251, Japan.
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa, 252-5210, Japan.
Sci Rep. 2022 Aug 26;12(1):14577. doi: 10.1038/s41598-022-18634-6.
The planetary missions including the Venus Climate Orbiter 'Akatsuki' provide new information on various atmospheric phenomena. Nevertheless, it is difficult to elucidate their three-dimensional structures globally and continuously only from observations because satellite observations are considerably limited in time and space. We constructed the first 'objective analysis' of Venus' atmosphere by assimilating cloud-top horizontal winds on the dayside from the equator to mid-latitudes, which is frequently obtained from Akatsuki's Ultraviolet Imager (UVI). The three-dimensional structures of thermal tides, found recently to play a crucial role in maintaining the super rotation, are greatly improved by the data assimilation. This result is confirmed by comparison with Akatsuki's temperature observations. The momentum transport caused by the thermal tides and other disturbances are also modified by the wind assimilation and agrees well with those estimated from the UVI observations. The assimilated dataset is reliable and will be open to the public along with the Akatsuki observations for further investigation of Venus' atmospheric phenomena.
包括金星气候轨道器“晓”号在内的行星探测任务提供了有关各种大气现象的新信息。然而，仅通过观测很难在全球范围内持续阐明它们的三维结构，因为卫星观测在时间和空间上有很大限制。我们通过同化“晓”号紫外成像仪（UVI）经常获取的赤道至中纬度白天云顶水平风，构建了金星大气的首个“客观分析”。热成潮的三维结构最近被发现对维持超自转起着关键作用，通过数据同化得到了极大改善。与“晓”号的温度观测结果对比证实了这一结果。热成潮和其他扰动引起的动量输送也因风同化而得到修正，并且与UVI观测估计值吻合良好。同化数据集是可靠的，将与“晓”号观测数据一起向公众开放，以供进一步研究金星大气现象。
