三峡水库大宁河流域非点源污染参数的不确定性分析

Analyzing parameter uncertainty of the non-point source pollution in Daning River of the Three Gorges Reservoir area

以大宁河流域为研究区,在基于参数敏感性分析的基础上,分别选取对径流量、泥沙负荷、有机氮和有机磷模拟计算最敏感的前10位参数,采用FOEA(first-order error analysis)不确定性分析方法,分析这些参数对非点源负荷不确定性的影响.结果表明,仅有少数几个参数对模型输出结果的不确定性有显著影响,这些参数对不确定性的贡献在90%以上.对泥沙负荷、有机氮、有机磷模拟计算的不确定性影响最大的是径流曲线数,说明非点源污染负荷的不确定性主要受径流产生过程的参数的影响.在径流量、泥沙负荷、有机氮和有机磷4个输出结果中,泥沙的不确定性最大.

Using Darting River watershed as study area, based on parameter sensitivity analysis, ten first most sensitive simulated calculating parameters of the runoff amount, silt load, organic N and organic P were chosen respectively, and the uncertain analysis method of FOEA （first-order error analysis） was adopted to analyze the influence of these parameters on the non-point source uncertainty.Only a few parameters had remarkable influence on uncertainty of the model output result, and contribution of these parameters for simulation results was higher than 90%. The greatest influence on the uncertainty of simulated calculating of silt load, organic N and organic P was runoff curve number, indicating that the uncertainty of non-point source pollution load was influenced mainly by the parameters of the runoff producing process. In the four output results of runoff amount, silt load, organic N and organic P, the uncertainty of silt was the greatest.