北半球月平均环流异常年际演变的准周期特征及跃变现象

THE QUASI-PERIODIC FEATURE AND JUMP PHENOMENON FOR THE INTERANNUAL VARIATION OF NORTHERN HEMISPHERE MONTHLY MEAN GENERAL CIRCULATION ANOMALIES

本文利用一种时空综合的经验正交函数(EOF)方法,分析了北半球100,500和700hPa 3层1和7月的月平均高度距平场,得到了反映北半球月平均环流异常三维空间结构的特征向量场及其对应的时间系数。利用功率谱和最大熵谱分析,并引入“气候跃变”的概念研究了时间系数年际演变的特征。结果表明:北半球月平均环流异常年际演变的过程具有准周期特征及不连续的跃变现象。

In this paper, the joint- space and time EOF method is used to analyse 100, 500 and 700 hPa geopotential height anomaly fields in January and July. The eigenvectors indicate not only the distribution features in three dimension structure but also the organic relationship between them. The interannual variation features of time-coefficient are discussed using power spectrum and maximum entropy spectrum method as well as 'climate jump' conception. The results show: there are the quasi-periodic features and unsuccessive jump phenomena in the interannual variation processes of Northern Hemisphere monthly mean general circulation anomalies.