中文摘要：

利用1960~2004年河北平原6个站点的降水量资料,采用线性拟合、Mann-Kendall（M-K）法及Morlet小波分析方法,对河北平原45年四季降水量进行了倾向、突变和周期特性的分析。结果表明：（1）45年间春季和冬季降水呈增加趋势,夏季和秋季降水则呈减少的趋势。四季降水距平百分率的倾向率分别为1.39%/10a、5.132%/10a、6.332%/10a和5.516%/10a。（2）45年间的四季降水量呈现出阶段性变化的特点,其中春季和冬季降水变化不显著,没有突变。而夏季和秋季降水在20世纪70年代中期后呈现较明显的减少。（3）在95%的置信度下,45年间的四季降水量均呈现出3~4年的周期性变化,此外,春季降水还存在着6年左右的周期振荡。

英文摘要：

In order to investigate the varying characteristics of seasonal rainfall in Hebei Plain,the rainfall data from 1960 to 2004 over six meteorological stations in Hebei Plain were analyzed by using linear regression,Mann-Kendall and Morlet wavelet analysis method.The results showed that the rainfall increased in spring and winter,decreased in summer and autumn through 45 years.The tendency rate of seasonal rainfall abnormally percentage were 1.39%/10a,5.132%/10a,6.332%/10a and 5.516%/ 10a,respectively.There was no significant abrupt change of rainfall in spring and winter,significant abrupt change of rainfall occurred in summer and winter in middle 1970s.The seasonal rainfall through 45 years exhibited periodic variations of 3-4 years,with a 95% degree of confidence.Also,6 years of periodic variation occurred in spring rainfall.