黄河干流年径流量非一致性频率计算

Study on non-stationary frequency calculations for the annual runoff of Yellow River mainstream

采用具有时变统计参数的GAMLSS(generalized additive model for location, scale and shape)模型,研究黄河干流年径流系列的非一致性水文频率计算方法。首先介绍了模型结构、参数估计及拟合效果的评价方法,然后在分析6个水文站1956—2017年年径流量变化趋势的基础上,构建非一致性水文频率计算备选模型集,选取AIC值最小的概率分布类型和参数作为最优模型,通过残差序列的统计特征和设计径流量的分位数图检验模型拟合效果。结果表明本文所构建的各优选模型与径流序列的拟合效果较好,各站年天然径流系列对应的设计径流量有随时间减少的趋势。在水资源评价和调配中,应充分考虑径流的非一致性特点,开展变化环境下水资源的预报预测及不确定性评估工作。

This paper presents an application of a generalized additive model for location,scale and shape(GAMLSS)with time-varying statistical parameters to calculations of the non-stationary hydrological frequencies of annual runoff series of the Yellow River mainstream.First,we discuss the evaluation methods of model structure,parameter estimation,and fitting effect.Then,we construct a set of alternative models for non-stationary hydrological frequency calculation,based on analysis of runoff change trends of the annual series of six hydrological stations at the Yellow mainstream for the period of 1956 to 2017,and select the optimal model as featured with the probability distribution type and parameter setting that has the minimum AIC value.This model and its fitting effect are tested against the statistical characteristics of the residual series and the quantile plot of design runoffs.From the test,the optimized model manifests good fitting to the runoff series,and the design runoffs corresponding to the runoff series of each station decrease with time.Thus,we suggest that the future evaluation,allocation or operation of water resources fully consider the non-stationary effect of runoffs and carry out predictions and uncertainty assessment of water resources in changing environments.