Spatio-temporal stability analysis applied to monsoon anticyclone flow
Spatio-temporal stability analysis applied to monsoon anticyclone flow
复制标题
季风反气旋流时空稳定性分析
DOI：
10.1002/qj.3771
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发表时间：
2020
影响因子：
8.9
通讯作者：
Rupp P
中科院分区：
文献类型：
--
作者：
Rupp P
由稳定的局部反气旋性位涡强迫（或等效的质量源）驱动的β平面上的流动被认为是对流层上部亚洲季风流动的一个简单模式。以前的作者已经注意到，根据强迫的大小，响应可能是稳定的，也可能是不稳定的，不稳定表现为向西的涡旋脱落。对稳定和涡旋脱落状态之间的过渡的详细研究揭示了第三种状态（“破裂”），对于中等强迫强度，在强迫附近的气流是稳定的，但向西延伸的低位涡羽破裂成孤立的反气旋涡，远离强迫区。一个相关的时空不稳定性问题的β平面上的流动指定和分析。流动可以是稳定的、对流不稳定的或绝对不稳定的。有人认为，这三个稳定性制度对应于稳定，破碎和涡脱落制度的强制流动和良好的定量对应制度之间的时空稳定性问题的显式解决方案证明。
Flow on a beta‐plane driven by a steady localised anticyclonic forcing of potential vorticity (or equivalently a mass source) is considered as a simple model of the Asian monsoon flow in the upper troposphere. Previous authors have noted that the response may be steady, or unsteady, according to the magnitude of the forcing, with the unsteadiness manifested as westward eddy shedding. A detailed study of the transition between steady and eddy‐shedding regimes reveals a third regime ('break up'), for intermediate forcing magnitude, where the flow is steady in the neighbourhood of the forcing, but the westward extending plume of low potential vorticity breaks up into isolated anticyclonic vortices some distance away from the forcing region. A related spatio‐temporal instability problem for flow on a beta plane is specified and analysed. The flow can be stable, convectively unstable or absolutely unstable. It is argued that these three stability regimes correspond to the steady, break‐up and eddy‐shedding regimes for the forced flow and good quantitative correspondence between the regimes is demonstrated by explicit solution of the spatio‐temporal stability problem.