近60年清涧河洪峰流量极值的变化特征分析

Analysis on Variation Characteristics of Extreme Value of Flood Peak Flow of Qingjian River during 1954—2017

以清涧河流域水文站延川站和子长站建站以来的场次洪水实测洪峰流量为研究数据,通过线性倾向分析与累积距平分析其变化趋势,并通过R/S法进行可持续性分析;利用M-K检验进行突变分析,采用复Morlet小波来诊断清涧河洪峰流量的周期特征,并分析洪峰流量极值与降水量极值的相关性。结果表明,清涧河年最大洪峰流量均发生在6、7、8、9月,集中发生在7和8月,且以发生在0:00—5:59、18:00—23:59的时间段内为主;年最大洪峰流量在波动变化的过程中呈现减少趋势,减少趋势具有微弱持续性;在该时间段年最大洪峰流量发生突变,突变点为2007年;小波分析结果显示,在该时间段内存在4、7、11年的周期,控制着年最大洪峰流量变化过程;相关性检验表明洪峰流量极值与降水量极值在α=0.05的显著性水平上相关系数不显著。

Adopted the measured flood peak flow value which based on Yanchuan and Zichang stations since the Qingjian River basin hydrology station as research data.Then,its variation trend through the cumulative anomaly and the linear trend estimation were analyzed,and the sustainability analysis through R/S method was carried out,in addition to use the M-K test for the mutation analysis,and also the Morlet complex wavelet was used to diagnose the periodical characteristics of the flood peak discharge of the Qingjian River.Furthermore,the correlation between the peak value of the flood peak discharge and the extreme value of precipitation was analyzed.The results indicated that the annual peak discharges of the Qingjian River occurred in June,July,August and September.The concentrations occurred in July and August,and occurred at 0:00—5:59,18:00—23:59.The main time period was dominated;The annual maximum peak discharge showed a decreasing trend in the process of fluctuations,and the decreasing trend had a weak persistence;During this time period,the annual maximum peak flood flow occured abruptly changes,and the mutation point was in 2007;Wavelet analysis results showed that the period of quasi-4a,7a and 11a were within this time period,which controled the annual maximum peak flood flow change process;Correlation tests showed that the correlation coefficient between the peak value of flood peak flow and the extreme value of precipitation atα=0.05 was not significant.