What causes Mars' annular polar vortices?
What causes Mars' annular polar vortices?
复制标题
火星环形极涡的形成原因是什么？
DOI：
--
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
S. Guzewich
中科院分区：
文献类型：
--
作者：
A. Toigo;D. Waugh;S. Guzewich
火星大气的一个显著特征是冬季极地涡旋表现出高位涡（PV）环空，在极附近有一个局部最小值。这些环空可以在火星的观测、再分析和自由运行的大气环流模型模拟中看到，但通常不是地球极地涡旋的特征，因为地球极地涡旋的PV值随纬度单调增加。火星上环状极涡的形成和维持尚不清楚。在这里，我们使用火星环流模型的模拟来表明，环形涡与火星大气的另一个独特的，可能是太阳系中独一无二的特征有关：极地冬季地区主要大气气体（CO2）的凝结。与CO2冷凝相关的潜热导致极地低层大气中PV的破坏，诱导形成环状PV结构。
A distinctive feature of the Martian atmosphere is that the winter polar vortices exhibit annuli of high potential vorticity (PV) with a local minimum near the pole. These annuli are seen in observations, reanalyses, and free‐running general circulation model simulations of Mars, but are not generally a feature of Earth's polar vortices, where there is a monotonic increase in magnitude of PV with latitude. The creation and maintenance of the annular polar vortices on Mars are not well understood. Here we use simulations with a Martian general circulation model to the show that annular vortices are related to another distinctive, and possibly unique in the solar system, feature of the Martian atmosphere: the condensation of the predominant atmospheric gas species (CO2) in polar winter regions. The latent heat associated with CO2 condensation leads to destruction of PV in the polar lower atmosphere, inducing the formation of an annular PV structure.