The Atlantic Jet Response to Stratospheric Events: A Regime Perspective
The Atlantic Jet Response to Stratospheric Events: A Regime Perspective
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DOI：
10.1029/2020jd033358
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发表时间：
2021-03
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影响因子：
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通讯作者：
M. Goss;E. Lindgren;A. Sheshadri;N. Diffenbaugh
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作者：
M. Goss;E. Lindgren;A. Sheshadri;N. Diffenbaugh
对流层对平流层突然警告(SSW)的响应与中纬度急流和相关风暴路径向赤道方向移动有关，而强烈的极涡(SPV)事件则引起相反的响应。最近利用急流纬度指数的概率密度函数对北大西洋急流进行的分析确定了三个偏爱的急流纬度，这提出了一个问题，即对流层对SSW和SPV的响应是否是这些偏爱的急流的相对频率变化的结果，而不是系统的急流漂移。我们使用1979-2018年的大气再分析资料(26个SSW和33个SPV)和202年来全大气社区气候模式(92个SSW和68个SPV)的积分来探讨这个问题。在SSW之后，北部急流系统变得不常见，而中部和南部系统变得更常见。这些变化几乎立即发生在“分裂”涡旋事件之后，但在“位移”事件之后延迟更多。相反，在SPV事件之后，北部政权变得更加频繁，而南方政权变得不那么频繁。在SSW之后，500百帕位势高度、地面气温和降水的合成最接近于南方急流的合成，而在符号上通常与北方的急流的合成相反。在SPV之后，这些比较是相反的。因此，一种可能的解释是，最南端的两个政权似乎在SSW之后受到青睐，而最南端的政权在SPV之后变得不那么常见。
The tropospheric response to Sudden Stratospheric Warmings (SSWs) is associated with an equatorward shift in the midlatitude jet and associated storm tracks, while Strong Polar Vortex (SPV) events elicit a contrasting response. Recent analyses of the North Atlantic jet using probability density functions of a jet latitude index have identified three preferred jet latitudes, raising the question of whether the tropospheric response to SSWs and SPVs results from a change in relative frequencies of these preferred jet regimes rather than a systematic jet shift. We explore this question using atmospheric reanalysis data from 1979 to 2018 (26 SSWs and 33 SPVs), and a 202‐years integration of the Whole Atmosphere Community Climate Model (92 SSWs and 68 SPVs). Following SSWs, the northern jet regime becomes less common and the central and southern regimes become more common. These changes occur almost immediately following “split” vortex events, but are more delayed following “displacement” events. In contrast, the northern regime becomes more frequent and the southern regime less frequent following SPV events. Following SSWs, composites of 500‐hPa geopotential heights, surface air temperatures, and precipitation most closely resemble composites of the southern jet regime, and are generally opposite in sign to the composites of the northern jet regime. These comparisons are reversed following SPVs. Thus, one possible interpretation is that the two southernmost regimes appear to be favored following SSWs, while the southernmost regime becomes less common following SPVs.