半个世纪以来鞍山市春夏季降水的变化特征

利用1951～2004年计54 a鞍山市逐年春夏季降水资料,采用线性趋势估计法、小波分析方法等统计学方法,分析了鞍山市半个世纪以来春夏季降水的变化特征。结果表明:鞍山市春季降水线性变化趋势为增加趋势,其线性变率为2 mm/10 a,夏季降水线性变化趋势为减少趋势,其线性变率为5 mm/10 a,并且从80年代开始春夏季降水的不稳定性开始增强。春季降水存在着4～6 a和16～18 a的主要变化周期,夏季降水有18～20 a和6～8 a的主要变化周期,各周期变化在不同时期起着主导作用。

Characteristics of spring and summer rainfalls in Anshan from 1951 to 2004

Based on spring and summer rainfalls data in Anshan from 1951 to 2004,the characteristics of spring and summer rainfalls were analyzed with linear trend estimation method and wavelet analysis method.The results showed that spring rainfall in Anshan displayed an upward trend with 2 mm/10a,while summer rainfall was a downward trend with 5 mm/10a.The instabilities of spring and summer rainfalls increased since the 1980s.There were periodical changes with 4-6 years and 16-18 years in spring rainfall variation and with 6-8 years and 18-20 years in summer rainfall variation.The different periodical changes played dominant roles in different periods.