基于改进的两参数月水量平衡模型的月径流模拟

对熊立华等提出的两参数月水量平衡模型进行了分析,辨析了模型参数的物理意义,针对模型计算公式中的不合理之处,对原模型作了改进:首先,考虑到降水和流域前期蓄水量对流域蒸散发的共同作用,将两者同时作为影响因子,构造了新的蒸散发计算公式;其次,根据有关参数的变化范围,用线性函数近似双曲正切函数,改进了月径流量计算公式.运用改进后的模型模拟、验证了北运河通县站控制流域1980~1991年的月径流和蒸散发过程.结果表明,较之原模型,改进后的模型精度更高,月径流计算过程与实测过程拟合效果较好,年内最大洪峰流量相对误差明显减小,模拟的月蒸散发和流域蓄水量过程更加合理.

Monthly runoff simulation based on improved two-parameter monthly water volume balance model

A research was conducted on the two-parameter monthly water volume balance model proposed by Xiong Lihua,et al.It is found that the physical meanings of the parameters in the model are not very clear.Especially,the rationality of the equations for evaportranspiration and runoff should be further investigated.Thus,the model was improved in two aspects: a new formula for calculation of evaportranspiration was constructed with the effects of precipitation and river basin water storage at former stage on evaportranspiration considered synchronously;the monthly runoff formula was simplified by approximation of hyperbolic tangent function with a linear function according to the variation range of related parameters.The application of the improved model to hydrology simulation of Tongxian watershed of the North Great Canal for 1980-1991 shows that the improved model is of high accuracy,the calculated result of monthly runoff is in good agreement with the measured data,and the relative error of the annual peak flood is evidently decreased.Therefore,the improved model is superior to the original model for simulation of monthly evaportranspiration and river basin water storage.