The Impact of Tropical Precipitation on Summertime Euro-Atlantic Circulation via a Circumglobal Wave Train
The Impact of Tropical Precipitation on Summertime Euro-Atlantic Circulation via a Circumglobal Wave Train
复制标题
热带降水通过环全球波列对夏季欧洲大西洋环流的影响
DOI：
10.1175/jcli-d-17-0451.1
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发表时间：
2018
影响因子：
4.9
通讯作者：
A. Weisheimer
中科院分区：
文献类型：
--
作者：
C. O’Reilly;T. Woollings;L. Zanna;A. Weisheimer
研究了热带降水变率对欧洲-大西洋区夏季季节环流异常的影响。欧洲-大西洋环流和热带降水之间的最大协方差分析（MCA）的主导模式显示，北大西洋温带上空存在气旋异常，导致西欧异常潮湿，东欧和斯堪的纳维亚半岛异常干燥（正相）。热带降水变率的相关模式与热带太平洋海温异常有关，并与厄尔尼诺-南方涛动（ENSO）密切相关。第二个MCA模式由较弱的热带降水异常，但有一个较强的外热带信号，反映了内部大气的变化。遥相关机制进行了测试，在正压模式模拟，这表明，所观察到的热带降水的主导模式和欧洲-大西洋环流异常之间的联系在很大程度上是一致的线性Rossby波动力学。正压模式的响应包括一个环全球波列在热带外，主要是被迫在热带太平洋东部的散度异常。Rossby波向东和向西的群传播被认为是重要的，在确定欧洲-大西洋部门的环流响应。该机制还分析了业务的季节预报系统，ECMWF的系统4。虽然系统4能够很好地再现和巧妙地预测热带降水，但在欧洲-大西洋地区，热带外环流响应是不存在的，这可能与亚洲急流的偏差有关。
The influence of tropical precipitation variability on summertime seasonal circulation anomalies in the Euro-Atlantic sector is investigated. The dominant mode of the maximum covariance analysis (MCA) between the Euro-Atlantic circulation and tropical precipitation reveals a cyclonic anomaly over the extratropical North Atlantic, contributing to anomalously wet conditions over western Europe and dry conditions over eastern Europe and Scandinavia (in the positive phase). The related mode of tropical precipitation variability is associated with tropical Pacific SST anomalies and is closely linked to the El Niño–Southern Oscillation (ENSO). The second MCA mode consists of weaker tropical precipitation anomalies but with a stronger extratropical signal that reflects internal atmospheric variability. The teleconnection mechanism is tested in barotropic model simulations, which indicate that the observed link between the dominant mode of tropical precipitation and the Euro-Atlantic circulation anomalies is largely consistent with linear Rossby wave dynamics. The barotropic model response consists of a circumglobal wave train in the extratropics that is primarily forced by divergence anomalies in the eastern tropical Pacific. Both the eastward and westward group propagation of the Rossby waves are found to be important in determining the circulation response over the Euro-Atlantic sector. The mechanism was also analyzed in an operational seasonal forecasting system, ECMWF’s System 4. While System 4 is well able to reproduce and skillfully forecast the tropical precipitation, the extratropical circulation response is absent over the Euro-Atlantic region, which is likely related to biases in the Asian jet stream.
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影响因子：
8.9
作者：
Petrie, R. E.;Shaffrey, L. C.;Sutton, R. T.
通讯作者：
Sutton, R. T.
影响因子：
4.6
作者：
Donges, Jonathan F.;Petrova, Irina;Kurths, Juergen
通讯作者：
Kurths, Juergen
影响因子：
4.6
作者：
C. O’Reilly
通讯作者：
C. O’Reilly
DOI：
10.5194/tc-13-3093-2019
发表时间：
2019-05
期刊：
The Cryosphere
影响因子：
--
作者：
M. Cooper;Thomas M. Jordan;D. M. Schroeder;M. J. Siegert;Christopher N. Williams;J. Bamber
通讯作者：
M. Cooper;Thomas M. Jordan;D. M. Schroeder;M. J. Siegert;Christopher N. Williams;J. Bamber