基于EVT法和MC模型的极限水文干旱历时计算研究  

Calculation of critical hydrological drought duration based on EVT method and MC model

作　　者：赵纬 宋松柏[1] 张更喜 ZHAO Wei;SONG Songbai;ZHANG Gengxi(College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling,Shaanxi 712100,China)

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《西北农林科技大学学报（自然科学版）》2018年第11期129-135,共7页Journal of Northwest A&F University(Natural Science Edition)

基　　金：国家自然科学基金项目(51479171;51179160;50879070);高等学校博士学科点专项科研基金项目(20110204110017)

摘　　要：【目的】研究极值理论(extreme value theory,EVT)法和马尔科夫链(Markov chain,MC)模型在极限干旱历时计算中的预测精度,为区域干旱历时预报提供依据。【方法】以黄河流域兰州、龙门、白马寺3个水文站年径流序列为例,利用EVT法和MC模型2种方法分别计算不同截断水平对应的极限干旱历时(Expected longest duration,E(LT)),并采用纳什效率系数(Nash-Sutcliffe efficiency coefficient,NS)和平均绝对百分误差(Mean absolute percentage error,MAPE)评价2种方法的计算精度。【结果】兰州、龙门、白马寺3个水文站采用EVT法计算的极限干旱历时值E(LT)与对应观测值(Observed longest duration,LT-ob)的NS和MAPE分别为0.921 0,0.854 6,0.929 4和0.046 0,0.155 5,0.039 1;而一阶马尔科夫链(one-order Markov chain,MC-1)模型结合hazen绘点位置公式计算的极限干旱历时值与对应观测值的NS和MAPE分别为0.824 7,0.668 1,0.908 1和0.206 3,0.327 3,0.104 6。2种方法均可取得较好的计算效果,但EVT法的计算精度优于MC-1模型。【结论】EVT法较MC-1模型所需要的参数少,计算过程较为简单,且计算结果误差小,是黄河流域可行的极限干旱历时计算方法。【Objective】This study investigated the accuracy of the extreme value theory(EVT)and the Markov chain(MC)model in predicting critical drought duration on regional scale.【Method】Based on the annual runoff data of 3 hydrological stations in the Yellow River Basin,critical drought duration was modeled using two methods with different threshold levels.The best method was obtained based on Nash-Sutcliffe efficiency coefficient and mean absolute percentage error.【Result】The values of NS and MAPE based on EVT at Lanzhou,Longmen and Baimasi hydrological stations were 0.921 0,0.854 6,0.929 4 and 0.046 0,0.155 5,0.039 1 respectively,while those based on the one-order Markov chain model(MC-1)and hazen were 0.824 7,0.668 1,0.908 1 and 0.206 3,0.327 3,0.104 6,respectively.High accuracy was obtained by both methods,and EVT was better.【Conclusion】Compared with the MC-1 models,EVT was simpler,more accurate with less parameters in predicting critical drought durations for the Yellow River Basin.

关 键 词：极限水文干旱历时 马尔科夫链 极值理论 径流预测 黄河流域 

分 类 号：P333.9[天文地球—水文科学]