银川市近49a来降雨变化特征分析

根据银川市4个气象站(银川站、永宁站、贺兰站、灵武站)近49 a(1960—2008年)的实测降雨资料,运用统计学理论、回归分析、Mann-Kendall非参数检验、克里金插值等方法进行研究,依据有关统计量的计算结果,分析了银川市近49 a来降雨量的时空变化特征.研究结果表明:银川市年内降雨量分配不均,夏季降雨量最大,占全年降雨量的56.83%~58.32%,冬季最小,仅占全年降雨量的1.93%~2.07%;年际以及年代际降雨量变化大,多年平均降雨量为186.7 mm,且以20世纪60年代降雨量最大,90年代降雨量最小.经Mann-Kendall非参数检验和一元线性回归分析,发现银川市降雨量呈现逐年减小的趋势,Mann-Kendall非参数检验趋势系数β为-0.18 mm/a,线性回归倾向率为-5.386 mm/(10 a).银川市降雨量还存在空间分布不均的特点,灵武市降雨量最大,减小的趋势最小;贺兰县降雨量最小,减小的趋势最大.

Analysis on Characteristics of Precipitation Variation over the Past 49 Years in Yinchuan City of China

According to the observational rainfall data collected from weather station including Yinchuan Station,Yongning Station,Helan Station and Lingwu Station in Yinchuan area,the characteristics of precipitation variation over the past 49 years from 1960 to 2008 in Yinchuan City were analyzed and studied with the methal of the theory of statistics,regression analysis,Mann-Kendall nonparametric test and Cringing interpolation as well as the calculation of correlative statistic.The study results show,that rainfall distributes disproportionationally in a year,precipitation is largest in summer,rainfall accounts for 56.83%~58.32% of total rainfall in a whole year,and rainfall in winter accounted for the least proportion which is 1.93%~2.07%.Rainfall changes a lot in different years and different decades,perennial average precipitation is 186.7 mm and rainfall in 1960s is largestm,while rainfall in 1990s is smallest.After tested by Mann-Kendall nonparametric and analyzed by monadic linear regression,a downtrend of precipitation is found,and Mann-Kendall nonparametric test trend coefficient β is-0.18 mm/a,regression analysis tendency rate is-5.386 mm/（10 a）.Rainfall in Yinchuan city present disproportionational spatial distribution,rainfall in Lingwu is the largest and the downtrend is the smallest,while in Helan county,the rainfall is the smallest and the downtrend is the largest.