Atmospheric circulation cells associated with anomalous east Asian winter monsoon
Atmospheric circulation cells associated with anomalous east Asian winter monsoon
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DOI：
10.1007/s00376-010-0100-6
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发表时间：
2011-06
影响因子：
5.8
通讯作者：
G. Zeng;Wei‐Chyung Wang;Zhaobo Sun;Zhongxian Li
中科院分区：
文献类型：
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作者：
G. Zeng;Wei‐Chyung Wang;Zhaobo Sun;Zhongxian Li
利用1948/49~2002/03 NCEP/NCAR再分析和NCAR CAM3大气环流模式对1950~2000年全球月平均海温资料进行了研究。太平洋的几个大气环流单元[即热带的纬向Walker环流(ZWC)、西太平洋的Hadley环流(WPHC)、北太平洋中部的中纬度环流(MZC)和东太平洋的Hadley环流(EPHC)]都与东亚季风异常有关。当EAWM较强时，ZWC、WPHC和MZC增强，而不是EPHC。ZWC异常增强的特征是气团在热带西太平洋上升，在对流层高层向东流动，在热带中太平洋下降，然后返回热带西太平洋。增强的MZC具有与北太平洋中部增强的ZWC相反的特征。WPHC异常显示气团在西太平洋上升，如ZWC，然后在对流层上层向北流动，在西北太平洋下降，如MZC增强后返回热带西太平洋。异常的EPHC在性质上与异常的WPHC相反。在弱东亚季风期间，发现了相反的特征。模式模拟和观测结果显示了相似的特征，表明了海表面温度的重要作用。提出了一种可能的EAWM年际变化与热带太平洋中东部海温异常(SSTA)联系的机制。
Atmospheric circulation cells associated with anomalous East Asian Winter Monsoon (EAWM) were studied using the 1948/49 to 2002/03 NCEP/NCAR reanalysis and NCAR CAM3 AGCM simulations with monthly global sea surface temperatures from 1950 to 2000. Several atmospheric cells in the Pacific [i.e., the zonal Walker cell (ZWC) in the tropic, the Hadley cell in the western Pacific (WPHC), the midlatitude zonal cell (MZC) over the central North Pacific, and the Hadley cell in the eastern Pacific (EPHC)] are associated with anomalous EAWM. When the EAWM is strong, ZWC, WPHC, and MZC are enhanced, as opposed to EPHC. The anomalous enhanced ZWC is characterized by air parcels rising in the western tropical Pacific, flowing eastward in the upper troposphere, and descending in the tropical central Pacific before returning to the tropical western Pacific. The enhanced MZC has characteristics opposite those of the enhanced ZWC in the central North Pacific. The anomalous WPHC shows air parcels rising in the western Pacific, as in the case of ZWC, followed by flowing northward in the upper troposphere and descending in the west North Pacific, as in the case of the enhanced MZC before returning to the western tropical Pacific. The anomalous EPHC is opposite in properties to the anomalous WPHC. Opposite characteristics are found during the weak EAWM period. The model simulations and the observations show similar characteristics and indicate the important role of sea surface temperature. A possible mechanism is proposed to link interannual variation of EAWM with the central-eastern tropical Pacific sea surface temperature anomaly (SSTA).