四川秋季连阴雨的变化特征和时空分布

摘要

Using 47 a(1961-2007) daily precipitation data from 38 stations in Sichuan during September-November,this paper analyses variation characteristics and space-time distribution of continuous rainfall in autumn of Sichuan from aspects of frequency,precipitation amount,and durative days by means of several modern diagnostic methods in meteorological statistics.The results show that the precipitation amount in autumn in Sichuan makes up about a quarter of annual precipitation,and the precipitation amount of continuous rainfall in autumn accounts for about one fifth,which is 80 percent of the precipitation of autumn rainfall in Sichuan.The frequency,precipitation amount and the durative days all have a decreasing trend in the mass.This decreasing phenomenon is a kind of mutation and appears in later period of 1980s.The continuous rainfall in autumn increases in western Sichuan while decreases in the east as a whole.According to analysis results by EOF,the overriding spatial pattern belongs to the antiphase distribution between the east and the west of Sichuan.%利用1961-2007年四川省38个站9-11月的日降水资料,从发生次数、降水量和持续天数三方面资料,应用现代气候统计诊断方法,对四川秋季连阴雨的变化特征和时空分布进行了分析.结果表明:四川秋雨量约占四川全年降水量的四分之一,其中秋季连阴雨量约占全年降永的五分之一、约占秋雨量的80％；四川秋季连阴雨的发生次数、降水量和持续天数总体上均呈减少趋势,这种减少是一种突变现象,发生在1980s中后期；从地域上来看,四川秋季连阴雨总体上呈西部增多、东部减少的趋势；EOF分析结果表明四川秋季连阴雨最主要的特征为东西反相型分布.