Control of the oscillations of the martian Northern Hemisphere polar vortex by the Hadley cell and topographic forcing
Control of the oscillations of the martian Northern Hemisphere polar vortex by the Hadley cell and topographic forcing
复制标题
哈德来环流和地形强迫对火星北半球极涡振荡的控制
DOI：
10.1016/j.icarus.2022.115019
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发表时间：
2022
期刊：
影响因子：
3.2
通讯作者：
Mester M
中科院分区：
文献类型：
--
作者：
Mester M
本文用Kida涡旋模型研究了火星北方半球极涡的振荡，并对再分析资料中的涡旋动力学进行了解释。涡旋章动周围的一个固定的角度，其纵横比的变化不大被证明是由哈德利细胞和波数-2行星尺度波，其特征在于与一个固定的组件，被证明是直接链接到火星地形控制。波强迫和Hadley胞结构被模拟为应变和旋转流在Kida的模型。结果表明，应变和旋转流是强烈的负相关，反对涡的伸长在Kida的模型。结果表明，高地形强迫事件的时期伴随着哈德利环流的减弱，从而解释了为什么火星上很少发生涡旋分裂。
The oscillations of the Martian Northern Hemisphere polar vortex are examined by using the Kida vortex model to interpret the dynamics of the vortex in reanalysis data. The vortex nutating around a fixed angle with little variability in its aspect ratio is shown to be controlled by the Hadley cell and wavenumber-2 planetary-scale waves that are characterised with a stationary component that is shown to be linked directly to Martian topography. The wave forcing and the Hadley cell structure are modelled as a strain and a rotational flow in Kida’s model. It is shown that the strain and rotational flow are strongly negatively correlated, acting against vortex elongation in Kida’s model. The result suggests that periods of high topographic forcing events are accompanied with a weakening in the Hadley cell winds and thus provides an explanation why vortex splits are rare on Mars.