Phase speed spectra and the recent poleward shift of Southern Hemisphere surface westerlies
Phase speed spectra and the recent poleward shift of Southern Hemisphere surface westerlies
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DOI：
10.1029/2007gl031200
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发表时间：
2007-11-03
影响因子：
5.2
通讯作者：
Held, Isaac M.
中科院分区：
文献类型：
--
作者：
Chen, Gang;Held, Isaac M.
利用再分析资料和海气耦合模式及非耦合大气模式的输出资料，研究了近几十年来南半球地面西风带的极向移动。对流层上部涡旋动量通量的时空谱显示了一种趋势，即对流层涡旋的东向相速度增加，同时伴随着副热带波破碎区的极向位移。一个动力学机制的建议，可能有助于解释低平流层风异常，增加对流层涡旋的东向传播和对流层环流的极移之间的联系。
The poleward shift of the Southern Hemisphere surface westerlies in recent decades is examined in reanalysis data and in the output of coupled atmosphere- ocean and uncoupled atmospheric models. The space- time spectra of the eddy momentum fluxes in the upper troposphere reveal a trend that marks an increase in the eastward phase speed of the tropospheric eddies accompanied by a poleward displacement of the region of wave breaking in the subtropics. A dynamical mechanism is suggested that may help explain the connections among the lower stratospheric wind anomalies, the increased eastward propagation of tropospheric eddies and the poleward shift of the tropospheric circulation.