SCS-CN模型中CN值的空间移用效果研究

SCS-CN模型因其曲线数CN值可以根据下垫面(土壤和植被)确定,近年来在分布式水文模拟和无/缺资料地区得到较为广泛的应用。美国土壤保持局提供的CN查算表在中国地区并不完全适用,如果直接采用,可能会带来较大的径流计算误差。选择资料数据较好的北京柏崖厂站作为假定的无实测径流资料的目标站,通过相似流域特性分析确定北山下站为参证站,利用参证站资料计算出CN值校正系数,并将该系数引用到目标站,利用校正前后的CN值分别模拟多场次洪水。结果表明,SCS-CN模型的参数CN值修正后,在空间上具备一定的外推能力;无论在确定性系数、径流总量精度和洪峰流量精度上,CN值修正后的洪水预报精度都要比修正前要高。

Research on spatial extrapolation ability of CN in SCS-CN Model

The Soil Conservation Service Curve Number（SCS-CN） methodology has been widely used in distributed hydrological simulation and ungauged region in recent years because its curve number CN can be determined by the characterizations of the underlying surface (soil and vegetation). The CN consult table provided by the United States Soil Conservation Service canis not be completely applieduseful infor China, and it would result inbring a large deviation if it iswe directly used it in the runoff calculation. This paper selects chooses Baiyachang Station in Beijing with relatively complete hydrologic data as the target station, which is assumed to have no measured runoff data, and through the characteristic analysis of similar basin, Beishanxia station is confirmed as a reference station. Then we calculated the correction coefficient for CN parameters by using reference station data and appliedy the coefficient to the target station and simulate several flood using the non- revised and revised CN parameters. The results show that the revised CN parameters has some extrapolating abilitiesy inon space and the accuracy of flood forecasting can be improved in terms of deterministic coefficient, total runoff and peak discharge.