Daily to Decadal Modulation of Jet Variability
Daily to Decadal Modulation of Jet Variability
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DOI：
10.1175/jcli-d-17-0286.1
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发表时间：
2017-11
影响因子：
4.9
通讯作者：
T. Woollings;E. Barnes;B. Hoskins;Young‐Oh Kwon;R. Lee;Camille Li;E. Madonna;M. McGraw;Tess Parker;R. Rodrigues;C. Spensberger;K. Williams
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文献类型：
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作者：
T. Woollings;E. Barnes;B. Hoskins;Young‐Oh Kwon;R. Lee;Camille Li;E. Madonna;M. McGraw;Tess Parker;R. Rodrigues;C. Spensberger;K. Williams
急流位置在纬度上的变化与其平均速度有关：当急流变得更强时，它在纬度上的变化减小。这种关系被证明是持有观察到的中纬度喷气机在世界各地，也跨越层次的数值模型。北大西洋急流变率被证明是调制在十年的时间尺度上，几十年的强，稳定的射流穿插几十年的弱，可变的射流。这些调制也与全流域发生的高影响阻塞事件的变化有关。一幅复杂的数十年急流变率的图像出现了，近几十年来似乎并不罕见。我们提出了一个基本的正压机制来解释这种行为，与射流的折射特性的变化，因为它加强，以及随后的影响Rossby波破碎的分布。
AbstractThe variance of a jet’s position in latitude is found to be related to its average speed: when a jet becomes stronger its variability in latitude decreases. This relationship is shown to hold for observed midlatitude jets around the world and also across a hierarchy of numerical models. North Atlantic jet variability is shown to be modulated on decadal timescales, with decades of a strong, steady jet being interspersed with decades of a weak, variable jet. These modulations are also related to variations in the basin-wide occurrence of high-impact blocking events. A picture emerges of complex multidecadal jet variability in which recent decades do not appear unusual. We propose an underlying barotropic mechanism to explain this behaviour, related to the change in refractive properties of a jet as it strengthens, and the subsequent effect on the distribution of Rossby wave breaking.