北半球500百帕极地环流与厄尔尼诺、南方涛动及我国气温场的遥相关

TELECORRELATION OF THE 500 hPa POLAR CIRCULATION AND EL NINO/SO WITH THE TEMPERATURE FIELDS IN CHINA

本文用1951—1984年的资料对500百帕、65°N以北的高度场作自然正交展开,用模糊聚类对典型场归类。指出,极涡月平均场有三种形态,1月份平均场形态较特殊;大尺度距平场也有三种形态,4月份距平场形态较特殊。此外,研究了典型场的时间权重系数与厄尔尼诺、南方涛动的关系。指出,厄尔尼诺现象发生的当年4月、10月极地大尺度距平场有明显的异常特征。这种极地环流异常已明显影响到我国4月份、10月份的气温场。因而,可能是厄尔尼诺年我国气温4月偏低、10月偏高的一个重要原因。

By using the monthly data from 1951 through 1984, empirical orthogonal ex-pansion is performed for the 500 hPa geopotential height north of 65°N and the canonicalfields are clustered by fuzzy classification. It is noted that both the mean monthly polarvortex fields and the large-scale anomaly fields fall into three regimes, with those ofthe January mean field and the April anomaly field having characteristic features. In ad-dition,the relationship between the time weighing coefficients of the canonical fields andEl Nino/SO is examined,showing significant anomalies in the large-scale polar anoma-ly fields during April and October of the year when E1 Nino occurs. These polar circula-tion anomalies havd considerably influenced the temperature fields in China during Apriland October. Thus, we may conclude that this is one of the most important reasons for arelatively cool April and a warm October in China during the El Nino year.