中文摘要：

利用甘肃省80个气象站建站至2012年3-5月的降水量资料,分析了甘肃省春季降水的基本气候特征;通过EOF、REOF、小波分析等方法,对甘肃春季降水的时空特性进行了研究,用Mann-Kendall检验法检验了甘肃春季降水序列是否存在突变现象.结果表明,甘肃春季降水空间分布极不均匀,其空间分布特征是东南部为多雨区、西北部为少雨区.甘肃春季降水在第一空间尺度上为全区一致,在第二空间尺度上可分为2个自然气候区,在第三空间尺度上可分为7个自然气候区.从年代际变化来看,1960年代是近50 a来降水最多的10 a,1990年代是降水最少的10 a;甘肃春季降水的年际变率十分显著,降水最多的年份是最少年份的近5倍.1961-2012年间甘肃春季降水发生了明显的突变,1982年出现了一次增多趋势的突变,1992年出现了一次减少趋势的突变.5 a的短周期和18~19 a的长周期是其主要周期.甘肃春季降水偏少（多）年份的500 hPa异常环流形势为极涡弱（强）、中纬度亚洲为一脊一槽型、东亚大槽深（浅）、南支槽浅（深）.

英文摘要：

Using the precipitation data from 80 representative observation stations in Gansu Province from 1961 to2012,the climatic characteristics of spring precipitation were analyzed. EOF,REOF and power spectrum methods were used to research the spatial and temporal characteristics of spring precipitation in Gansu Province.Whether there were mutations in the spring precipitation sequence was tested by Mann-Kendall test. The results showed that the spatial distribution of spring precipitation in Gansu Province was extremely uneven,the rainy area located in the southeast,and the less rain area located in the northwest. The spring precipitation was consistent in the entire region at the first space scale,two natural climate zones at the second space scale and seven natural climate zones at the third space scale. The 1960 s was the decade of most abundant precipitation for nearly half a century. The 1990 s was the decade of least precipitation. The annual variation of the spring precipitation was significant in the province. Precipitation in the most precipitation year was 5 times more than that in the least precipitation year. There were obvious mutations in the spring precipitation in the province from 1961 to 2012. An increasing mutation occurred in 1982 and a decreasing mutation occurred in 1992. Short period of 5 years and long period of 18-19 years were the two major cycles. In those years of less（ more） spring precipitation in the province,the abnormal circulation at 500 hPa would be weak（ strong） polar vortex,one-ridge and one-trough located in mid-latitude of Asia,deep（ shallow） Eastern Asia trough and shallow（ deep） southern branch trough.