Interannual Relationship between the Boreal Spring Arctic Oscillation and the Northern Hemisphere Hadley Circulation Extent
Interannual Relationship between the Boreal Spring Arctic Oscillation and the Northern Hemisphere Hadley Circulation Extent
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春季北极涛动与北半球哈得来环流范围的年际关系
DOI：
10.1175/jcli-d-18-0657.1
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发表时间：
2019
影响因子：
4.9
通讯作者：
Guan Zhaoyong
中科院分区：
文献类型：
--
作者：
Hu Dingzhu;Guo Yi Peng;Tan Zhe Min;Guan Zhaoyong
研究了北半球春季北极涛动(AO)与北半球Hadley环流范围(HCE)的年际关系和动力联系。春季北极涛动与海温呈正相关，与海温的极移约为0.42°对应着海温指数的一个标准正偏差。副热带地区行星波和纬向风的相互作用导致了涡动动量通量散度的异常变化，从而使HCE向极地移动。与AO相关的瞬时涡动动量通量散度对HCE变化的贡献比定常分量的贡献大近2倍。副热带地区赤道向瞬变波通量的增加可能与那里瞬变波折射率的经向梯度较大有关。AO正位相对应于从中纬度大西洋到亚热带的行星波传播增强，这类似于北大西洋涛动模式。秋季和冬季的AO-HCE关系与春季相似，夏季的相关性最弱，这主要是由于夏季气候学的HCE向远极延伸所致。
This study investigates the interannual relationship and the dynamical linkage between the boreal spring Arctic Oscillation (AO) and the Northern Hemisphere Hadley circulation extent (HCE). The spring AO is positively correlated with the HCE, with one standard positive deviation of the AO index corresponding to approximately 0.42° latitude poleward shift of the HCE. The interaction between the planetary wave and the zonal winds over the subtropics results in an anomalous eddy momentum flux divergence, which shifts the HCE poleward. The AO related transient eddy momentum flux divergence makes nearly 2 times larger contributions than those of the stationary component to the HCE change. The increased equatorward transient wave flux over the subtropics is possibly related to the larger meridional gradient of the transient wave refractive index there. The AO positive phase corresponds to an enhanced planetary wave propagation from the midlatitude Atlantic Ocean to the subtropics, which resembles the North Atlantic Oscillation pattern. The autumn and winter AO–HCE relationship is similar to that during spring, while summer has the weakest relationship, which could be mainly attributed to the far poleward extension of the climatological HCE during summer.