砚瓦川流域1981-2012年降水特性及趋势分析

我国西北地区流域降水特性及趋势对当地雨养农业及水土流失有重要的影响。选用1981-2012年马莲河砚瓦川流域的降水量资料,以集中度、变差系数、逐年距平、M-K非参数统计检验以及滑动t检验等方法分析了降水年内、年际、突变变化特征。结果表明:砚瓦川流域降水量年内分配不均,集中度较高,降水多分布在7、8月;年际变化较小,流域多年平均降水量为523.0mm,变差系数约为0.2。M-K非参数统计检验表明,整体变化趋势并不明显,与距平和变差系数分析的结果一致;滑动t检验和M-K检验的结果显示年降雨量序列没有出现突变值。

Analysis of rainfall characteristics and its tendency in Yanwachuan basin from 1981 to 2012

The characteristics and its tendency of rainfall in Northwest of China play an important role in rain-fed agriculture and soil and water erosion. The paper chose the data of rainfall in Yanwachuan basin from 1981 to 2012 and used concentration ratio, variation coefficient, anomaly, M-K non parametric statistical test and moving t-test technique to analyze the intra annual variation, annual variation and mutation change of rainfall. The result showed that the distribution of monthly precipitation is not even. The concentration ratio is high and precipitation occurred mostly in July and August;the annual variation is small, the average precipitation of long year is 523 mm, variation coefficient of precipitation is about 0.2.M-K mutation test showed that the trend of precipitation change is not obvious and the result is in accordance with that of the analysis of anomaly and variation coefficient.The result of moving t-test technique and M-K test showed that annual precipitation series has no abrupt change point.