基于Copula函数的叶尔羌河水沙丰枯遭遇研究

Water and Sediment Accumulation in Yarkant River Based on Copula Function

为了解叶尔羌河水沙关系发展规律,采用叶尔羌河卡群站、库鲁克栏干站的径流量和输沙量资料,利用模比系数法、滑动t检验法和滑动相关系数法诊断水沙关系变异点,基于Copula函数构建水沙二维联合分布模型,对比研究不同时段下的径流量与输沙量丰枯遭遇状况。结果显示:水沙关系在1993年前后发生突变,1993—2015年水沙相关性要强于1954—1992年水沙相关性:变异前后水沙丰枯遭遇同步概率均大于水沙丰枯遭遇异步概率,且“水丰沙枯”和“水枯沙丰”两种类型的概率均为0;1954—1992年水沙丰枯同步频率为58.97%,1993—2015年水沙丰枯同步频率达到82.61%,水沙关系变异后的水沙丰枯遭遇同步频率增加。研究结论可为叶尔羌河流域水沙运行调度与管理提供理论依据。

To obtain the development law of runoff and sediment relations in the Yarkant River Basin,the variation point of runoff and sediment relation was diagnosed using the method of modulus coefficient,moving t-test,and moving correlation coefficient based on the data of runoff and sediment of the Kagun and Langan hydrologic stations.The two-dimensional joint distribution model of runoff and sediment was constructed by Copula function.Results manifest that:1)The relationship between runoff and sediment changed dramatically around 1993.2)The correlation between runoff and sediment in 1993-2015 was stronger than that in 1954-1992.3)In different periods,the frequency of synchronous water and sediment was always larger than that of asynchronous water and sediment.The probability of“high water and low sediment”as well as“low water and high sediment”was both zero.4)The frequency of synchronous water and sediment reached 58.97%from 1954 to 1992,and 82.61%from 1993 to 2015,and ever increased after 1993.The research conclusions offer theoretical basis for the operation and management of water resource in the Yarkant River Basin.