近60年关中-天水经济区降水量特征分析

Analysis on Characteristic of Precipitation in Guanzhong-Tianshui Economic Zone in Recent 60 Years

降水等气候要素变化将会影响农业生产。采用传统统计、空间插值和距平累积分析等方法,对关中—天水经济区及其周边26个代表性气象站点1951—2009年59a系列的降水实测资料进行了分析。结果表明:(1)降水量从西北向东南递增,不同的降雨强度在各年代分布不均,并且降水日数与降水量变化不完全一致。(2)1950s—1970s降水量减少,1980s后降水量增加,进入1990s后,降水量又开始减少,2000年后降水量略有增加。(3)降水量变化特征大致可分为3个阶段。大部分站点年降水量1968年或1975年以前高于多年平均降水量,1968—1990年或1975—1990年期间,年降水量围绕多年平均降水量震荡,1990年后,降水量普遍低于多年平均值。

Climate factors including precipitation have significant effects on agricultural production.Traditional statistics,spatial interpolation and accumulated variance analysis methods are applied to analyze the change characteristics of precipitation in Guanzhong—Tianshui economic zone,based on the precipitation data of 26 weather stations in and around this region during 1951—2009.Results showed that：（1） Annual average rainfall increased gradually from northwest to southeast.The rainfall intensity distribution in this region is not even during decadal,and the changes of rainy days and precipitation are inconsistent;（2） The precipitation decreased from 1950s to 1970s,increased in 1980s,then began to decrease in 1990s,precipitation went up slightly after 2000;（3） The variation of precipitation could be divided into 3 stages.The precipitation of most of weather stations before 1968 or 1975 was more than the mean for many years,the precipitation between 1968 and 1990 or during 1975 to 1990 fluctuated at the mean for many years,and then precipitation was less than the mean for many years after 1990.