关河水库流域水文序列突变诊断与非一致性研究

在气候变化和人类活动影响下,近年来很多流域的水文序列发生了突变,呈现出了时间序列上的非一致性。同时,水文序列的自相关性影响其突变点的准确识别。为研究关河流域降雨以及径流序列的变化规律,根据流域内5个雨量站以及2个实测径流站点近50年的实测资料,利用Mann-Kendall秩次检验其趋势性,同时利用3种突变检验方法分别在无、有去趋势预置白(trend free pre-white,TFPW)前处理的条件下对序列突变点进行识别,并使用Morlet小波对序列进行周期性分析,从突变点诊断、周期性分析和驱动机制3方面剖析关河水库流域水文序列非一致性变化特点。研究结果表明:对系列的自相关性去除以后,TFPW对水文系列中初步识别出来的多个伪突变点有校正作用,有助于识别出真正的突变点,这一结论在随后的周期性分析Morlet小波方法中得到了验证。研究区降雨在1978年发生突变,径流在1979年发生突变,降水是引起两站径流产生突变的原因,且突变点前后径流序列的状态发生了根本性变化;相较于受单一气候影响的石栈道站,受气候因素以及人类活动双因素影响下的关河站其径流总量下降更为明显,径流变化周期不稳定且峰值有所减小。

Research on the Diagnosis of Hydrologic Series Abrupt Changes and Inconsistency in Guanhe Reservoir Basin

Under the influence of climate change and human activities,hydrologic series in many basins have shown mutative and inconsistency in recent years.In the meanwhile,the self-correlation of hydrologic series affects mutative identification.In order to study the variation characteristics of rainfall and runoff series in the Guanhe Reservoir Basin,based on the measured data of five rainfall station and two runoff stations within the basin for nearly 50 years,the Mann-Kendall rank test is used to test the trend,three approaches of Mann-Kendall,Pettitt and ordered aggregation are addressed to diagnose the mutation points,which are under two conditions:with or without the trend-free pre-whiting(TFPW)method,then the periodicities of these series are identified by Morlet wavelet further.The results show that the TFPW method could adjust the fake multi-mutation points after filtering out the correlation of series and to help determine the real points,which are verified by the periodic results from the Morlet wavelet method.The precipitation in the study area was mutated in 1978,while the runoff was mutuated in 1979.Precipitation is the main driver of the sudden change of runoff in the two stations,and the characteristic of these two runoff series have changed fundamentally around the abrupt change point.Compared with the Shizhandao Station,the annual runoff decline of Guanhe Station was more obvious,and unstable in periodicity and lower peak flow,not only impacted by climate change but human activities.