研究非一致性条件下枯水流量设计值对流域水资源管理具有重要意义,然而如今常用的时变矩法推求出的每年一个设计值很难用于实际。选取渭河流域实测枯水流量序列作为实例进行研究,将气象协变量引入到枯水流量频率分析,结合重现期的期望超过次数(Expected Number of Exceedances,ENE)概念推求非一致性条件下枯水流量设计值,并与传统以时间为协变量的情况进行比较。结果表明: 2种协变量情况下非一致性设计枯水流量相比于一致性结果存在明显差别,且以气温和降水为协变量的非一致性设计结果相比于时间为协变量更为合理。研究所得设计结果可为流域枯水期水资源管理提供一定参考依据。
英文摘要:
Design low-flow analysis under nonstationary conditions is a critical consideration in water resources management. The design low-flow varying from one year to the next obtained by using the time-varying moment method is hard to be applied to practical application. This paper is aimed to improve the characterization of nonstationary design low-flow under the expected number of exceedances (ENE) interpretation of return period by employing meteorological covariates in the nonstationary frequency analysis. The method of using time as the only covariate is also applied for comparison. Both methods are applied to the annual minimum monthly streamflow series of the Weihe River,China. Results demonstrate that the nonstationary design low-flow results of both methods are significantly different from the stationary case. The nonstationary design low-flow result using temperature and precipitation as covariates is found more reasonable and advisable than that of the case using time as covariate. It is concluded that nonstationary design low-flow analysis can be helpful to water resources management during dry seasons exacerbated by climate change.