热带太平洋El Nio Modoki对中国近海及邻近海域海温的可能影响

POSSIBLE IMPACT OF TROPICAL EL NIO MODOKI ON SST OF CHINA OFFSHORE AND ITS ADJACENT WATERS

1970年代末以后,热带太平洋海区出现了一种类似El Nio但又与其有本质区别的现象:El Nio Modoki,与其相关的各种海洋大气异常变化给全球气候带来了独特的影响。利用HadISST海温和NCEP/NCAR风场等再分析资料以及相关、回归和合成等统计方法,分析了El Nio Modoki与当年各季的中国近海及邻近海域海表温度(SST)的关系。结果表明:(1)夏季El Nio Modoki与同年秋季中国近海及邻近海域的SST有显著的负相关关系,显著相关区域主要分布于黑潮以东的大片海域。(2)夏季El Nio Modoki发生期间,菲律宾北部至中国近海及邻近海域的上空盛行异常偏北风,且热带西太平洋表层暖水东流,这不利于热带西太平洋暖水向中纬度地区的输送。分析结果还表明,海洋环境对风场有滞后的响应以及黑潮向北输送有减弱的现象,而这可能正是夏季El Nio Modoki影响秋季中国近海及邻近海域海温偏冷的重要原因。

E1 Nino Modoki, a new type of tropical Pacific phenomenon, which is similar but different from canonical E1 Nino, has been observed since the late 1970s, followed by its unique influence on global climate. In this paper, relationships between four seasons＇ SST in the offshore area of China and its adjacent waters and E1 Nifio Modoki have been compared and analyzed based on HadISST dataset and NCEP／NCAR wind data. Significant negative correlation is found between E1 Nino Modoki in summer and SST in the offshore area of China and its adjacent waters in autumn with the significant regions located in the east of the Kuroshio. During the El Nifio Modoki period, anomalous northerly winds prevail over the northern part of the Philipinese to the offshore area of China. It is therefore suggested that the northerlies are unfavorable for the transportation of warm water from the western tropic Pacific to mid-latitude areas. Consequently, E1 Nino Modoki in ＇summer may Contribute to the cold SSTs in the offshore area of China and its adjacent waters in autumn because of the lagging response of the ocean to winds and the weakening northward transportation of Kuroshio.