Atmospheric mountain wave generation on Venus and its influence on the solid planet’s rotation rate
Atmospheric mountain wave generation on Venus and its influence on the solid planet’s rotation rate
复制标题
金星上大气山波的产生及其对固体行星自转速率的影响
作者：
T. Navarro;G. Schubert;S. Lebonnois
Akatsuki航天器在金星云层顶部观测到一个10，000公里长的日冕结构，该结构相对于表面似乎是静止的，被解释为重力波。此外，在四个金星太阳日的观测中，其他这样的波被观测到出现在赤道高地地区的下午。这表明这颗固体行星对整个金星大气层的直接影响，尽管它们的自转速率分别为243天和4天。这样的重力波是如何在金星上产生的还不清楚。在这里，我们使用大气环流模型模拟金星大气表明，观测结果是一致的，与静止的重力波地形高或山波，在赤道地区产生的近地表大气稳定性的昼夜循环在下午。我们发现，这些山波大大有助于总的大气扭矩，作用在地球表面。我们估计，山波，沿着热潮和斜压波，可以产生约2分钟每太阳日的固体旋转速率的变化。固体行星和大气之间的这种相互作用可能解释了自转速率的一些差异（相当于一天的长度变化约7分钟）。金星的大气模拟显示，下午在山脉上空产生的重力波可以影响行星的旋转速度，并解释行星-Akatsuki宇宙飞船观测到的金星大气层的尺度扰动。
The Akatsuki spacecraft observed a 10,000-km-long meridional structure at the top of the cloud deck of Venus that appeared stationary with respect to the surface and was interpreted as a gravity wave. Additionally, over four Venus solar days of observations, other such waves were observed to appear in the afternoon over equatorial highland regions. This indicates a direct influence of the solid planet on the whole Venusian atmosphere despite dissimilar rotation rates of 243 and 4 days, respectively. How such gravity waves might be generated on Venus is not understood. Here, we use general circulation model simulations of the Venusian atmosphere to show that the observations are consistent with stationary gravity waves over topographic highs—or mountain waves—that are generated in the afternoon in equatorial regions by the diurnal cycle of near-surface atmospheric stability. We find that these mountain waves substantially contribute to the total atmospheric torque that acts on the planet’s surface. We estimate that mountain waves, along with the thermal tide and baroclinic waves, can produce a change in the rotation rate of the solid body of about 2 minutes per solar day. This interplay between the solid planet and atmosphere may explain some of the difference in rotation rates (equivalent to a change in the length of day of about 7 minutes) measured by spacecraft over the past 40 years.Atmospheric simulations of Venus show that gravity waves generated in the afternoon over mountains can influence the planet’s rotation rate and explain a planetary-scale perturbation of the Venusian atmosphere observed by the Akatsuki spacecraft.
影响因子：
3.2
作者：
Haus, R.;Kappel, D.;Arnold, G.
通讯作者：
Arnold, G.