Planetary-scale streak structure reproduced in high-resolution simulations of the Venus atmosphere with a low-stability layer
Planetary-scale streak structure reproduced in high-resolution simulations of the Venus atmosphere with a low-stability layer
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DOI：
10.1038/s41467-018-07919-y
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发表时间：
2019-01-09
影响因子：
16.6
通讯作者：
Hayashi, Yoshi-Yuki
中科院分区：
文献类型：
--
作者：
Kashimura, Hiroki;Sugimoto, Norihiko;Hayashi, Yoshi-Yuki
云的模式是揭示金星大气环流的重要线索。最近，在Akatsuki轨道飞行器上的2 μ m照相机IR2拍摄的金星夜面中低云图像中发现了行星尺度的条纹结构。然而，其形成机制尚未研究。在这里，我们成功地，第一次，在复制所观察到的条纹结构的模式，作为区域的强大的向下流动，在金星大气的高分辨率全球模拟发展。条纹形成于赤道对称的两半球，是由纬向波数为1的赤道类Rossby波和类Kelvin波引起的。过去的观测表明，低稳定层对于再现条纹结构是必不可少的。这种下降气流条纹是由类Rossby波的斜向倾斜相线与低稳定度层附近产生的斜压不稳定特征相互作用的结果。
Cloud patterns are important clues for revealing the atmospheric circulation of Venus. Recently, a planetary-scale streak structure has been discovered in middle- and lower-cloud images of Venus' night-side taken by IR2, the 2-mu m camera, on board the Akatsuki orbiter. However, its formation mechanism has not been investigated. Here we succeed, for the first time, in reproducing the patterns of the observed streak structure, as regions of strong downward flows that develop in high-resolution global simulations of the Venus atmosphere. The streaks are formed in both hemispheres with equatorial symmetry, which is caused by equatorial Rossby-like and Kelvin-like waves with zonal wavenumber one. The low-stability layer that has been suggested by past observations is essential for reproducing the streak structure. The streaks of downward flow result from the interaction of the meridionally tilted phase lines of the Rossby-like waves and the characteristics of baroclinic instability produced around the low-stability layer.