Planetary Waves and the Extratropical Winter Stratosphere
Planetary Waves and the Extratropical Winter Stratosphere
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行星波和温带冬季平流层
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发表时间：
2013
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通讯作者：
R. A. Plumb
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作者：
R. A. Plumb
平流层：地球物理学2010年版权所有B 10.1029/2009 GM行星尺度的Rossby波主导着冬季平流层的动态。查尼和德拉辛（Charney and Drazin，1961）在他们对这种波在平均状态下传播的经典分析中得出结论，只有在分点附近，当平均风是西风并且足够弱时，才允许深层垂直传播。随后的发展，特别是松野，纳入球面几何和纬度变化的平均状态的分析。波的折射率可以从平均状态确定;它被广泛地用于诊断波的传播特性，并且通常导致人们得出这样的结论：冬季西风带，即使在西风带最强的南方冬季，对这样的波也是透明的。然而，这样的结论依赖于WKB假设，这在存在平均状态的实际纬度变化时通常是不适当的。本文论证了Charney和Drazin的原始结论在性质上是正确的，在其未受干扰的辐射平衡状态下，冬季平流层不允许深波传播。这种传播需要西风减弱波本身，有人认为，波和平均流量之间随之而来的反馈是在平流层环流的强烈变化，包括发生重大变暖的心脏，并可能是中央平流层对流层相互作用。
The Stratosphere: Geophysical Mon Copyright 2010 b 10.1029/2009GM Planetary-scale Rossby waves dominate the dynamics of the winter stratosphere. In their classic analysis of the propagation of such waves on a mean state that varied only with height, Charney and Drazin (1961) concluded that deep vertical propagation is permitted only around the equinoxes,when themeanwinds arewesterly and sufficiently weak. Subsequent developments, especially by Matsuno, incorporated spherical geometry and latitudinal variations of the mean state into the analysis. A refractive index for the waves can be determined from the mean state; it has been widely used to diagnose wave propagation characteristics, and usually leads one to conclude that the winter westerlies, even in southern winter when the westerlies are strongest, are transparent to suchwaves.However, such conclusions rest onWentzelKramers-Brillouin (WKB) assumptions, which are often inappropriate in the presence of realistic latitudinal variations of the mean state. It is here argued that the original conclusions of Charney and Drazin are qualitatively correct and that in its undisturbed, radiative equilibrium state, thewinter stratosphere does not permit deep wave propagation. Such propagation requires the westerlies to be weakened by the waves themselves; it is argued that the consequent feedback between waves and the mean flow is at the heart of the strong variability of the stratospheric circulation, including the occurrence of major warmings, and may be central to stratospheretroposphere interactions.