ENSO循环过程对南极海冰的影响

应用 1 951- 2 0 0 2年NINO特征指数 (NINO1 +2 ,NINO3 ,NINO4 ,NINO3 .4)和 1 973-1 998年南极海冰北界范围以及 1 950- 2 0 0 1年SODA海洋温度资料。首先分析探讨了在ElNi no期间 ,堆积于赤道东太平洋的异常暖水在南半球的传播途径 ,进而研究了ENSO以及东南太平洋异常海温场与南极海冰之间的关系。结果表明 ,在ElNino期间 ,堆积于赤道东太平洋的异常暖水 ,是沿秘鲁和智利沿岸向极传播。其传播过程持续大约 1年的时间 ,但未发现沿南赤道流的西传现象。ENSO循环过程与南极海冰变化存在一定联系 ,特别是Amundsen Belling shausen海和南极半岛海冰的变化与ENSO暖事件 (ElNino)较为密切。当ElNino事件发生后 ,时滞 2年左右的时间 ,Amundsen Bellingshausen海和南极半岛的海冰将出现明显的减少现象 ,特别是南极半岛的海冰减少最为明显。ElNino事件对南极海冰的影响过程是 ,堆积于赤道东太平洋的大量异常暖水 ,沿南美 (秘鲁和智利 )沿岸近海向极地传播 ,异常暖水的这种向极传播过程将引起近极的海温场出现异常升高 ,最终导致Amundsen Bellingshausen海和南极半岛地区的海冰减少。自 2 0世纪 80年代以来 ,Amundsen Bellingshausen海和南极半岛的海冰出现明显减少的趋势 ,与这一时期的ElNino事件的频繁发生

IMPACT OF THE ENSO EPISODES ON THE VARIABILITY OF THE ANTARCTIC SEA ICE EXTENT

In this paper, the spreading way in the southern hemisphere that anomalous warm water piled in tropical eastern Pacific is analysed and then impact of ENSO episodes on the variability of the Antarctic sea ice extent is investigated by using a dataset from 1970 to 2002. The analysis results show that in ENSO period the anomalous warm water piled in tropical eastern Pacific is poleward propagation and westward propagation along southern equator current hasn't been discovered . The time of the anomalous warm water poleward propagation is about 1 year or so. ENSO episodes has a close relationship with the sea ice extent in the Amundsen Sea, Bellingshausen Sea and Antarctic Peninsula. Two years after El Nino appears, the sea ice in the Amundsen Sea, Bellingshausen Sea, especially in the Antarctic Peninsula decreases obviously. The process that El Nino influences Antarctic sea ice extent is that the warm water piled in tropical eastern Pacific is propagated poleward along the coast of southern America and causes the anomalous temperature raise near the pole and then lead to the decrease of the sea ice in Amundsen Sea, Bellingshausen Sea and Antarctic Peninsula. The sea ice has decreased obviously since 1980s, which has relevance to the frequent appearance of El Nino.