两类中太平洋El nino特征
投稿时间: 2015-11-09  最后修改时间: 2015-12-25  点此下载全文
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作者单位E-mail
郭品文 南京信息工程大学 guo@nuist.edu.cn 
张攀全 南京信息工程大学  
张福颖 南京信息工程大学  
尹依雯 南京信息工程大学  
沈沉 南京信息工程大学  
中文摘要:利用1979—2012年逐月Hadley中心海表温度、欧洲中期天气预报中心次表层海温、NCEP/NCAR风场再分析资料,对两类中太平洋(CP)El Nino及耦合的大气环流特征进行分析。结果表明,第一类CP El Nino(CP-I El Nino)冬季成熟后增暖中心位于Niño4区且关于赤道对称;第二类CP El Nino(CP-II El Nino)的Niño4区与热带东北太平洋区域(NEP,130˚W~110˚W、15˚N~25˚N)同位相变化,冬季成熟后形成关于赤道非对称的带状增暖结构。进一步的研究表明,两类CP El Nino次表层结构存在差异:CP-I El Nino冬季次表层海温异常(SOTA)在中东太平洋与西太平洋呈显著偶极分布;CP-II El Nino在中、西太平洋位相相反但东太平洋异常较弱,且经向异常主要在赤道及其以北。两类CP El Nino耦合的大气环流特征不同:CP-I El Niño冬季异常Walker环流上升中心位于赤道上空,经向风向赤道辐合,低纬地区Hadley环流加强;CP-II El Nino冬季低层向北越赤道气流加强,Walker环流上升中心移到赤道以北,低纬地区Hadley环流减弱。
中文关键词:CP El Nino  海表温度  次表层海温  大气环流
 
Characteristics of two types of central Pacific El Nino
Abstract:Abstract: Based on monthly Hadley Center sea surface temperature, ECMWF ocean subsurface temperature and NCEP/NCAR reanalysis datasets of wind from 1979 to 2012, the characteristics of two types of central Pacific (CP) El Nino and coupled atmospheric processes are studied. results show that there are two types of CP El Nino, CP-I El Nino and CP-II El Nino. CP-I El Nino has symmetrical structure about the equator and the warming center locate at Nino4 regions. For CP-II El Nino, the sea surface temperature anomalies (SSTA) change in phase between Nino4 regions and tropical northeast Pacific areas (NEP, 130˚W~110˚W, 15˚N~25˚N) , with a banded and asymmetric structure of SSTA forming in the winter. Further research indicates that the subsurface temperature anomalies (SOTA) of these two types of El Nino are different. In the CP-I El Niño winter, a zonal dipole mode forms between western and central eastern pacific. However, in the CP-II El Niño winter, a zonal dipole mode confines in the western and central pacific, with tiny SOTA in the eastern pacific and meridional SOTA also confine in the north hemisphere. Characteristics of atmospheric circulation are distinct between these two types of El Nino. In the CP-I El Nino winter, the anomalous ascent of walker circulation is over equator with convergent meridional wind anomalies in the equatorial areas. the Hadley circulation intensifies in the low latitude regions. In the CP-II El Nino winter, the cross-equatorial flow strengthens in the low level atmosphere, and the upwelling center of Walker circulation moves to north hemisphere. the Hadley circulation weakens in the low latitude regions to the contrary.
keywords:CP El Nino  Sea Surface Temperature  Ocean Subsurface Temperature  Atmospheric Circulation
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