摘要
选用8种概率分布函数,以极大似然法估计函数参数,采用AIC、BIC和AICc模型选择准则选出最优分布函数,系统分析变化环境下东江龙川和河源2站的极值流量特征,并对年最大流量变化规律及其影响做有益探讨。结果表明:降雨和水库蓄水工程是年最大流量显著下降的主要原因。龙川和河源站年最大流量LN2混尾分布拟合最好,变化环境后洪水频率最优分布线型基本保持一致,但流量变小造成分布参数改变已导致分布线型高水尾部特性变缓,相应设计流量偏小。用水文情势发生变化前估计的洪水重现期不能很好描述变化后洪水频率特征。
No ＂stationarity＂ existed any longer in the environmental background for the formation of runoff series.Designed by the existing engineering hydrologic analysis method will face the risk of distortion in design frequency caused by the ever-changing environment.We analyzed the statistical properties of hydrologic extreme flow for hydrologic station of Longchuan and Heyuan in Dongjiang river using 8 probability distribution functions.Estimate of parameters was performed using the maximum likelihood technique.Goodness of fit was done based on AIC,BIC and AICc for the optimal linear frequency distribution before and after environment change.And the rules and effects of variability for hydrologic extreme flow was discussed.The research results indicate that the non-stationary annual maximum daily flow series of stations in Dongjiang Basin show a descend trend that caused by rainfall and construction of water conservancy projects.Mixed tail distribution（LN2） at Longchuan and Heyuan stations were found to be the best fitting model.The optimal linear frequency distribution maintain consistency before and after environment change,but the impacts on fitting curve of flood series showed an overall performance as upper tail from ＂steep＂ to ＂gentle＂.The Changing properties and impacts of parameters to distribution are analyzed by the 30-year moving average method.Flood frequency analyses for Dongjiang river show that the maximum flow with a 0.01-annual probability（corresponding to 100-year flood peak under stationary conditions） over the 56-year record has ranged from a maximum discharge of 9 189 m3/s to a minimum of 2 305 m3/s at longchuan station;and has ranged from a maximum discharge of 11 125 m3/ s to a minimum of 4 072 m3/s at Heyuan station.If the non-stationarity of series is not considered,the traditional method is still used for calculation.At the Longchuan and Heyuan Stations,the design flood magnitude will be overestimated.Compared with non-stationary flood series characteristics,the flood magnitude is smaller and the frequency is lower for the stationary ＂real＂ flood series characteristics caused by hydraulic engineering regulation and rainfall.After changes in the hydrological regime,the flood return period estimated before the change is often unable to well describe the flood frequency characteristics after environmental changes.
出处
《地理科学》
CSCD
北大核心
2013年第7期851-858,共8页
Scientia Geographica Sinica
基金
国家自然科学基金重大国际合作和重点项目(51210013
50839005)
国家自然科学基金(51209095)
国家自然科学基金项目(41001019)资助
水利部公益性行业科研专项经费项目专题(200901043-3)
广东省科技厅项目(2010B050300010)
广东省水利科技创新项目(2009-39)
中山大学重大项目培育和新兴交叉学科项目(10lgzd11)
国家重点基础研究发展计划(973)项目(2010CB428405)
广东省自然科学基金(S2011040005992)
关键词
频率分析
概率分布函数
极值流量
非一致性
东江流域
Frequency analysis
probability distribution functions
stream flow extremes
non-stationarity
Dongjiang river
