1965—2013年渭河流域降水时空变化分析

利用1965—2013年渭河流域及其周边22个气象站点的降水数据,采用线性回归、经验正交函数(EOF)分解和Mann-Kendall突变性检验等方法,分析了渭河流域近50 a降水的时空分布特征。结果表明:1)从时间变化来看,在0.05显著性水平上,除春季降水呈现明显减小趋势外(-6.23 mm/10 a),其他季节和全年降水量的变化均不明显。同时,突变分析表明春季降水存在明显的突变,1991年为其突变点,其他季节和年降水均不存在显著的突变。2)渭河流域降水空间分布不均,总体呈现由东南向西北减小的趋势,从变化趋势空间分布来看,上游的减少趋势大于中游地区。3)EOF分解结果表明,渭河流域全年和四季降水的空间分布存在总体一致型和东南—西北区域反位相型的分布类型。

Spatial and Temporal Variation of Precipitation in Weihe River Basin from 1965 to 2013

Linear regression, the decomposition of Empirical Orthogonal Function (EOF), Mann-Kendall Test and Pettitt Test are used to analyze the spatial-temporal distribution characteristics of precipitation in the Weihe River Basin in 49 years based on the data from 1965 to 2013 at 22 meteorological stations in the Weihe River Basin and nearby. The results showed: 1) From the view of temporal variation, the changes of annual and seasonal precipitation were not significant at the level of 0.05 but the precipitation in spring which showed an obvious decreasing trend (-6.23 mm/10 a). Meantime, there was no obvious abrupt change of annual and seasonal precipitations but the spring of 1991 on basis of mutation test. 2) Precipitation in the Weihe River Basin was unevenly distributed, decreasing spatially from southeast to northwest, and the decreasing trend in the upstream was more obvious than that in the midstream. 3) The EOF decomposition indicated that the spatial distribution of annual and seasonal precipitation in the Weihe River Basin are overall coherent, and there was an opposite phase in the direction of southeast-northwest.