A Sensitivity Study of the Thermal Tides in the Venusian Atmosphere: Structures and Dynamical Effects on the Superrotation
A Sensitivity Study of the Thermal Tides in the Venusian Atmosphere: Structures and Dynamical Effects on the Superrotation
复制标题
金星大气层热潮汐的敏感性研究：结构和对超自转的动力学影响
DOI：
10.1029/2022je007243
复制
发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Matsuda Yoshihisa
中科院分区：
文献类型：
--
作者：
Suzuki Anna;Takagi Masahiro;Ando Hiroki;Imai Masataka;Sugimoto Norihiko;Matsuda Yoshihisa
为了解决目前金星大气热潮汐观测与数值研究之间的矛盾，我们利用大气环流模式，采用三种不同的大气静力稳定度分布，研究了上层云静力稳定度对热潮汐的影响。结果表明，半日潮垂直传播的垂直结构受静力稳定度的影响很大。在62-73 km高度上具有相当正压结构的日潮，虽然其垂直结构基本不变，但随着静稳定度的增加，日潮强度逐渐减弱。热潮汐的水平分布与实际的静止稳定度分布一致，与无线电掩星观测结果一致。与热潮汐相关的赤道角动量通量在赤道纬向平均风达到最大值的低纬度地区是向赤道方向的。这一结果与最近Akatsuki UVI观测结果一致，表明热潮汐可能有助于维持云顶附近赤道地区的超旋转。在最现实的情况下，纬向平均纬向风在52-76 km高度的低纬度地区被纬向和垂直角动量输送以0.2-0.5 m s− 1 day − 1的速率有效地加速。热潮汐还引起显著的纬向热通量，这在对纬向平均纬向风的动力作用中是不可忽略的。
In order to resolve discrepancy between recent observational and numerical studies on the thermal tides in the Venusian atmosphere, we investigated by means of a general circulation model how the thermal tides are affected by the static stability in and above the upper cloud layer by using three different distributions of the static stability. The results show that the vertical structure of the semidiurnal tide, which propagates vertically, is strongly affected by the static stability. The diurnal tide, which has an equivalent barotropic structure in 62–73 km altitudes, becomes weaker with the higher static stability although its vertical structure is almost unchanged. The horizontal distribution of the thermal tides with the realistic static stability distribution, which is consistent with radio occultation measurements, agrees with the observations at the cloud top. The meridional angular momentum flux associated with the thermal tides is equatorward in low latitudes near the altitude where the equatorial zonal‐mean wind takes its maximum. This result is consistent with the recent Akatsuki UVI observations, suggesting that the thermal tides could contribute to the maintenance of the superrotation in the equatorial region near the cloud top. In the most realistic case, the zonal‐mean zonal wind is effectively accelerated at rates of 0.2–0.5 m s−1day−1in low latitudes at altitudes of 52–76 km by both the meridional and vertical angular momentum transports. The thermal tides also induce significant meridional heat flux, which cannot be ignored in the dynamical effect on the zonal‐mean zonal wind.