1980—2016年清源河流域降水量时序变化规律及趋势研究

清源河是渭河的上游,属西北内陆典型小流域范畴,位于半干旱气候区,为了流域内水资源能够合理分配,对流域内降水量变化特征进行研究,掌握了其发展规律具有重要意义。本文采用垂直平分法对流域内的年平均降水量做了计算,采用不均匀系数法、集中期、极差法对降水量的年内分配进行了分析;采用线性回归法、斯波曼秩次相关法、Mann-Kendall秩次相关法对年降水量变化显著性进行了检验。结果表明:降水量年内分配极不均,主要集中在5—8月;年际变化趋于稳定,整体呈现不显著减小趋势;枯水期出现周期在2~8年,丰水期出现周期在4~10年,平水期持续时间短;降水量呈现由东北向西南递增趋势。经验证,本次研究成果精度相对较高,可以作为今后区域内水资源量计算等工作的参考依据。

Study on time series variation regularity and trend of precipitation in Qingyuan River basin from 1980 to 2016

Qingyuan River is the upper reaches of Weihe River, which belongs to the typical small watershed category of northwest inland, and is located in semi-arid climate zone. In order to distribute water resources reasonably in the watershed, it is of great significance to study the variation characteristics of precipitation in the watershed and master its development law.In this paper, the average annual precipitation in the basin is calculated by vertical bisection method, and the annual distribution of precipitation is analyzed by uneven coefficient method, concentration period method and range method.Linear regression method, Spearman rank correlation method and Mann-Kendall rank correlation method were used to test the significance of annual precipitation change.The results show that the annual distribution of precipitation is extremely uneven, mainly from May to August. The interannual variation tends to be stable, and the overall trend is not significantly decreasing.The occurrence period of dry season is 2~8 years, the occurrence period of wet season is 4~10 years, and the duration of flat season is short. The precipitation is increasing from northeast to southwest. It is proved that the accuracy of this research result is relatively high, and it can be used as a reference for the calculation of water resources in the region in the future.