改进SCS模型在老挝南乌河流域中的应用

为使SCS模型在老挝境内有更好的适用性,基于老挝南乌河流域下垫面条件及资料情况对SCS模型进行改进,即用前期影响雨量Pa代替前5 d降雨量来反映前期土壤的湿润程度;通过线性内插增加曲线号码CN值的分级数,并重新拟合滞留量S与CN的关系,修订了原模型S值的计算公式。应用结果表明:改进的SCS模型较原模型精度明显提高,可应用于南乌河流域的产流计算,同时可为其他无资料或缺资料地区的降雨径流模拟提供参考。

Application of modified SCS model in runoff calculation in Nam Ou Basin,Laos

For better applying the SCS model in Laos, according to the underlying surface conditions and data of the Nam Ou Basin in Laos, the SCS model was modified. First, the antecedent 5-day precipitation is substituted by antecedent influence rainfall Pa to reflect the soil moisture degree in the earlier period; the gradation number of the Curve Number is increased by linear interpolation; finally, the relationship between retention volume S and CN is re-fitted and the S calculating formula in the original model is revised. The results show that the accuracy of the modified SCS model is much higher than that of the original model, and it can be applied to the runoff calculation for the Nam Ou Basin and also provide reference for simulating the rainfall-runoff relationship in ungauged basins.