ENSO循环过程与南极海冰变化

ENSO events associated with the variation of the antarctic sea ice extent

应用1951-2001年ENSO特征指数(NINO1+2、NINO3、NINO4、NINO3 4、SOI)和1973-1998年南极海冰北界范围以及1950-2001年SODA海洋温度资料,分析探讨了ENSO循环过程与南极海冰之间的关系,研究了南大洋和太平洋海表温度与南极海冰之间的内在联系。结果表明,南极海冰变化与ENSO循环过程存在一定联系,特别是东南极海冰的变化与ENSO循环过程较为密切。这种遥相关关系表明,ENSO循环过程不仅与热带海洋自身的海 气相互作用存在密切关系,而且与南极海冰之间也存在一定的联系。当东南极海冰范围出现异常增大和减小时,在时滞一年之后,NINO循环指数将出现减弱和加强,而南方涛动指数将出现加强和减弱。这种相关关系的机制是通过大洋环流这一载体将异常海温向北输送来实现的。南极海冰范围的异常增加或减少,会直接影响南极绕极流的冷暖结构进而影响经向水体输送的异常,从而导致热带和副热带太平洋上层海温场的异常变化,对ElNino和LaNina事件的发生起到推动作用。

The relationship between the indexes of ENSO during 1951-2001 in the tropical Pacific and the Antarctic sea ice extents during 1973-1998 are analysed , and the relationship between the sea surface temperature in the Southern Ocean and in the Pacific during 1950-2001 and the Antarctic sea ice extents are studied.The result shows that the variations of the Antarctic sea ice extents especially in the Southeast Antarctica is closely related to the ENSO erents. This telecorrelation shows that the circulation process of ENSO is closely associated not only with air-sea interaction in the tropical Ocean but also with the variation of the Antarctic sea ice extent. If the extent of sea ice in Southeast Antarctic anomalous increases or decreases,after lagging a year′s, the indexes of El Nino and La Nina will become weaker and stronger accordingly, however the indexes of Southern Oscillation will become stranger or weaker accordingly. Such correlation machanism is achieved by the ocean circulation that transports the anomalous sea temperature from south to north. The anomalous variation of the Antarctic sea ice extent has an influence on the warmer and cooler structure of Antarctic Circumpolar Current and on the longitudinal transportation of anomalous warmer and cooler water, which leads to the anomalous variation of upper ocean in the tropical and subtropical Pacific, playing an important promotive role in the happening of El Nino or La Nina.