近50年来渭河流域降水变化特征分析

The characteristics of precipitation variation of Weihe River Basin in Shaanxi Province during recent 50 years

通过对渭河流域21个气象站1951-2005年降水观测资料统计分析,并运用累积距平曲线和信噪比法对渭河流域降水时空分布及变化进行了分析。结果表明：（1）渭河流域降水随海拔高度降低由西向东呈上升趋势,每下降100 m平均增幅约为15.1 mm;（2）自20世纪60年代以来,渭河流域年均降水呈下降趋势,10年平均减幅约为2 mm;（3）经降水变化的突变分析得出近50年渭河流域降水不存在突变年,1982、2003年为渭河流域大的降水转折年。

Based on the precipitation data of 21 stations in Weihe River Basin in Shaanxi Province in the recent 50 years（1951～2005）,and using Cumulative departure curve method and signal/noise radio method,the temporal-spatial change characteristics of precipitation over the region are analyzed.The results indicate：（1） With the lowering of altitude,the precipitation is rising from west to east in the Weihe River basin,and the range of increase is approximately 15.1 mm on average for each 100-meter lowering of altitude;（2） Since the 1960s,the average annual precipitation has assumed a drop tendency in the Weihe River,with about 2 mm on average for each decade;（3） There was no mutation year in the change of precipitation in the Weihe River Basin during the 50 years,but 1982 and 2003 seemed as transition years.