| Impacts of two types of El Niño on atmospheric circulation in the Southern Hemisphere |
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| 引用本文： | 孙丹,薛峰,周天军.Impacts of two types of El Ni?o on atmospheric circulation in the Southern Hemisphere[J].大气科学进展,2013,30(6):1732-1742. |
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| 作者姓名： | 孙丹 薛峰 周天军 |
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| 基金项目： | We would like to thank Dr. Bohua HUANG for his help, and the comments and suggestions from the two anonymous reviewers are also greatly appreciated. This study was jointly supported by the Strategic Priority Research Program of the Chinese Academy of Sciences （Grant No. XDA05110201） and the Development and Validation of High Resolution Climate System Model of the National Basic Research Program of China （Grant No. 2010CB951901）. |
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| 摘 要： | Based on NCEP/NCAR （National Centers for Environmental Prediction/National Center for Atmo- spheric Research） reanalysis data from 1979 to 2010, the impacts of two types of E1 Nino on atmospheric circulation in the Southern Hemisphere （SH） are analyzed. It is shown thaL when a warming event occurs in the equatorial eastern Pacific （EP E1 Nino）, there is a negative sea level pressure （SLP） anomaly in the east- ern Pacific and a positive one in the western Pacific. Besides, there exists a negative anomaly between 40°S and 60°S and a positive anomaly to the south of 60°S. When a warming event in the central Pacific （CP E1 Nino） occurs, there appears a negative SLP anomaly in the central Pacific and a positive SLP anomaly in the eastern and western Pacific, but the SLP anomalies are not so evident in the SH extratropics. In particular, the Pacific-South America （PSA） pattern induced by the CP E1 Nino is located more northwestward, with a weaker anomaly compared with the EP E1 Nino. This difference is directly related with the different position of heating centers associated with the two types of E1 Nino events. Because the SST anomaly associated with CP E1 Nino is located more westward than that associated with EP El Nino, the related heating center tends to move westward and the response of SH atmospheric circulation to the tropical heating changes accordingly, thus exciting a different position of the PSA pattern. It is also noted that the local meridional cell plays a role in the SH high latitudes during EP E1 Nino. The anomalous ascending motion due to the enhancement of convection over the eastern Pacific leads to an enhancement of the local Hadley cell and the meridional cell in the middle and high latitudes, which in turn induces an anomalous descending motion and the related positive anomaly of geopotential height over the Amundsen-Bellingshausen Sea.
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| 关 键 词： | 厄尔尼诺事件 大气环流 南半球 赤道东太平洋 Hadley环流 西太平洋地区 中高纬度地区 NCEP |
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