海洋和大气状态异常对西北太平洋台风活动的影响

本文分析了33年(1951—1983年)逐月平均的赤道东太平洋海温距平(SSTA)、热带西北太平洋500hPa高度距平和西北太平洋台风频数距平资料,指出:赤道东太平洋热力状况的异常对西北太平洋台风活动有明显影响。进一步对于1982—1983年的厄尼诺过程进行诊断分析,认为,SSTA异常可以通过经圈环流改变中、低纬环流的相互作用,以此来制约西北太平洋台风活动,即:当赤道东太平洋出现暖水时,北半球的哈得来环流加强,导致中纬度上空西风带加强、斜压扰动向南发展,结果,北半球副热带高压滞留在较低纬度、热带盛行东风气流,形成了不利于西北太平洋台风发生、发展的大尺度环流条件。

THE EFFECT OF THE ANOMALOUS STATE OF OCEAN AND ATMOSPHERE ON THE FREQUENCY OF TYPHOONS OVER THE WESTERN PACIFIC

It has been pointed out by analysis of data covered 33 years (from 1951 to 1983) that the effect of the anomalous thermal state of the equatorial Eastern Pacific on the frequency of typhoon over the Western Pacific is obvious. El Nino event in 1982-1983 indicated: by meridional cell, the anomalous SST (sea surface temperature) can affect the interaction between middle and low latitudes circulation, which restricted typhoon activities over the Western Pacific. In other words, when warm water occured in the equatorial Eastera Pacific, Hadley cell was intensified, which resulted in westerlies intensified and baroclinic disturbances eztends southward. As a result, subtropical high stayed in tropics and easterly flow prevailed in low latitude of Northern Hemisphere, which resulted in unfavourable situation of typhoon activities.