Synoptic Features Associated with Temporally Coherent Modes of Variability of the North Pacific Jet Stream
Synoptic Features Associated with Temporally Coherent Modes of Variability of the North Pacific Jet Stream
复制标题
与北太平洋急流变化的时间相干模式相关的天气特征
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Jonathan E. Martin
中科院分区：
文献类型：
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作者：
Kyle S. Griffin;Jonathan E. Martin
摘要：采用时间扩展EOF（TE-EOF）分析来研究北太平洋急流变率的两种主要模式的天气尺度演化，即纬向延伸-收缩（TE-EOF 1）和其出口区域的南北移动（TE-EOF 2）。使用 TE-EOF 分析可以对两种主要模态中每个峰值之前和之后的天气尺度演化进行时间相干检查，从而深入了解北太平洋急流的首选演化。基于在每个 TE-EOF 的两个阶段的主成分时间序列中选择幅度超过 1.5 个标准差的峰值来构建复合分析。急流扩展事件与阿拉斯加湾上空的异常气旋环流有关，该环流引起北美西部上空的低层温暖异常。喷射回缩与几乎相反的配置有关，其特征是阿留申群岛上空的异常反气旋环流和异常低...
AbstractTime-extended EOF (TE-EOF) analysis is employed to examine the synoptic-scale evolution of the two leading modes of the North Pacific jet stream variability, namely, its zonal extension–retraction (TE-EOF 1) and the north–south shift of its exit region (TE-EOF 2). Use of the TE-EOF analysis enables a temporally coherent examination of the synoptic-scale evolution preceding and following peaks in each of the two leading modes that provides insight into the preferred evolutions of the North Pacific jet.Composite analyses are constructed based upon selecting peaks in the principal component time series of both phases of each TE-EOF whose magnitude exceeded 1.5 standard deviations. Jet extension events are associated with an anomalous cyclonic circulation over the Gulf of Alaska that induces a low-level warm anomaly over western North America. Jet retractions are associated with a nearly opposite configuration characterized by an anomalous anticyclonic circulation over the Aleutians and anomalous low-...