Rossby Wave Propagation into the Northern Hemisphere Stratosphere: The Role of Zonal Phase Speed
Rossby Wave Propagation into the Northern Hemisphere Stratosphere: The Role of Zonal Phase Speed
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DOI：
10.1002/2017gl076886
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发表时间：
2018-02-28
影响因子：
5.2
通讯作者：
Jimenez-Esteve, Bernat
中科院分区：
文献类型：
--
作者：
Domeisen, Daniela I. V.;Martius, Olivia;Jimenez-Esteve, Bernat
平流层突然变暖(SSW)事件主要是由向上传播的行星波引起的。虽然理论预测对流层波强迫的纬向相速度影响波进入平流层的传播，但它与SSW事件的相关性到目前为止还没有被考虑到。这项研究在线性波诊断和再分析资料中显示，随着波的向上传播，相速度趋于东移，这表明平流层预先选择了向东的相速度进行传播，特别是对于纬向波数2。这也影响了SSW事件：分裂的SSW事件往往先于异常的东向的纬向相速度。纬向相速度确实可以解释在SSW事件的预条件期间观察到的波通量增加的部分原因，例如，对于创纪录的2009年SSW事件。
Sudden stratospheric warming (SSW) events are to a dominant part induced by upward propagating planetary waves. While theory predicts that the zonal phase speed of a tropospheric wave forcing affects wave propagation into the stratosphere, its relevance for SSW events has so far not been considered. This study shows in a linear wave diagnostic and in reanalysis data that phase speeds tend eastward as waves propagate upward, indicating that the stratosphere preselects eastward phase speeds for propagation, especially for zonal wave number 2. This also affects SSW events: Split SSW events tend to be preceded by anomalously eastward zonal phase speeds. Zonal phase speed may indeed explain part of the increased wave flux observed during the preconditioning of SSW events, as, for example, for the record 2009 SSW event.