摘要
为准确评价水文干旱,客观合理地构建干旱指数。以汾河上游的月径流为研究对象,首先从逻辑斯特、正态、对数正态、威布尔分布中选择出最优分布,利用最优分布计算标准径流干旱指数(Standardized Streamflow Drought Index,SSDI);其次依据标准正态曲线特点对水文干旱事件进行等级划分;最后将标准径流干旱指数与径流Z指数和距平指数进行分析比较,并根据汾河上游实际干旱情况验证标准径流指数的适用性。结果表明:对数正态分布对汾河上游月径流的拟合程度最佳,根据该分布计算得到的指数以及干旱等级与汾河上游历史记载的旱涝情况基本相符;汾河上游不同干旱等级出现频率相对于时间尺度的变化具有稳定性。
To accurately evaluate the hydrologic drought,it is necessary to objectively construct the drought index. In this study,the data collected from two hydrologic stations in the upper reaches of Fenhe River basin were used as case studies. Firstly,the ability of the logistic,normal,two-parameter log-normal,and Weibull probability distributions was examined to choose the most suitable distribution function for establishing the standardized streamflow drought index（ SSDI）. Secondly,the hydrologic drought magnitudes were divided based on the characteristics of standard normal curve. Finally,the SSDI was compared with the Z index and departure index of streamflow. The typical records of drought and flood events in the Fenhe River basin were taken as evaluation standard,which was used to evaluate the applicability and rationality of the SSDI and drought magnitudes. The results showed that,the two-parameter log-normal distribution was selected as the best fitting function for monthly streamflow in the study area. The SSDI and the magnitudes were both coincident for the actual drought-flood severity. In addition,the occurrence of various hydrologic drought magnitudes was stable at various time scales. The conclusion could provide scientific basis of drought defense,disaster mitigation,and water supply planning measures for the upper reaches of Fenhe River basin.
出处
《水科学进展》
EI
CAS
CSCD
北大核心
2016年第4期512-519,共8页
Advances in Water Science
基金
国家自然科学基金资助项目(40901018)
山西省科技攻关计划项目(20140313023-4)~~
关键词
概率分布函数
干旱指数
干旱等级
月径流
汾河上游
probability distribution function
drought index
drought magnitudes
monthly streamflow
the upper Fenhe River
