近45年青海省降水时空变化特征及突变分析

采用青海省39个气象台站自建站至2009年的降水资料,运用空间插值技术、Mann-Kendall方法、滑动t检验、Yamamoto和偏值分析方法分析了青海省降水时空变化特征。结果表明:(1)青海省降水存在自东向西逐渐减少特征,从空间分布上可分为东北部、西北部和南部3个区域。(2)近45年来青海省降水总体上呈弱增长趋势,但逐年值围绕多年平均值的波动较大,降水量少于平均值的年份相对较多。西北部与东北部在80年代后期降水呈波动增加,直到90年代才出现降水的减少,而南部地区则在80年代中期降水就开始减少,并持续到90年代结束,表明90年代青海省处在一个降水偏低期。(3)青海省在研究时间段内出现微弱的降水突变信号,各分区突变时间具有显著差异,其中西北部地区的突变始于1985年左右,南部出现在1980年左右,东北部则出现在2003年左右。

Characteristics of precipitation variation and the abrupt change over Qinghai in recent 45 years

With spatial interpolation method,Mann-Kendall,Moving-test technique,Yamamoto and the analysis of Partial value,the spatial-temporal features of precipitation in Qinghai were studied by using the precipitation data of 39 meteorological-stuations from the establishment to 2009a.The results showed that the precipitation had the trend of reducing gradually from the east to west,and the region was divided into the northeast、the northwest and the south.In recent 45 years,the precipitation had an slightly increasing trend,but the annual precipitation data around the average data fluctuated greatly.The precipitation in the northwest and the northeast fluctuated greatly in the late-1980s,and the reducing trend appeared in 1990s.However,that in the south begin to reduce from the mid-1980s to the end of 1990s.Above all indicated the state of precipitation in Qinghai was deficient in 1990s.Qinghai province had the weakly signal of the abrupt changes of precipitation,and every area had its own characteristics.The abrupt in the northwest appeared about 1985a,that in the south was about 1980a,and in the northeast was about 2003a.