径流曲线数模型(SCS-CN)参数λ在黄土丘陵区的率定

Calibration and validation to parameter λ of soil conservation service curve number method in hilly region of the loess plateau

径流曲线数模型(SCS-CN)用来计算降雨形成的地表径流量,参数λ是模型中的重要参数之一。本文在对径流曲线数模型参数λ敏感性分析的基础上,应用黄土丘陵区径流场62场实测降雨资料对参数λ与地表坡度关系进行了定量分析。结果表明,曲线数模型所描述的参数λ=0.2适合于黄土丘陵缓坡地,参数λ随着坡度的增大而减小;同时用实测降雨资料进行标定模型验证,得出径流量的预测值与实测值接近,其效率系数E=0.94,与直接运用模型计算径流量比较,效率系数有较显著提高。

The soil conservation service curve number（CN） method is widely used for predicting surface runoff from rainfall.Parameter λ is one of the important parameters.Based on sensitive analysis of parameter λ,analysis is made of the relation between λ and slope using the data of 62 times of rainfall. The results indicate that the parameter λ=0.2 is only applicable to gentle slope and decreases with the increase of slope degree,at the same time,measured surface runoff and predicted surface runoff are very consistent when calibrated model is validated with another rainfall data.Compared to standard CN method,the efficient coefficient E=0.94 is significantly developed.