瞬时单位线参数的率定与递归更新对地面径流模拟结果的影响  

Effect of Parameter Calibration and Recursive Updating of Instantaneous Unit Hydrographs on Results of Direct Runoff Simulations

作　　者：董晓华[1] 邓霞[1] 薄会娟[1] 李英海[1] 吕翠美[1] 

机构地区：[1]三峡大学水利与环境学院,湖北宜昌443002

出　　处：《三峡大学学报（自然科学版）》2010年第4期1-5,共5页Journal of China Three Gorges University：Natural Sciences

基　　金：国家自然科学基金项目(40701024)

摘　　要：在用瞬时单位线进行流域净雨的坡面汇流计算时,需要先率定其2个参数:线性水库的个数n及单个线性水库的调蓄系数K.传统参数率定方法为矩法,研究表明,使用矩法率定所得的瞬时单位线对地面径流的模拟精度较差,需要对参数进行更新.提出了一个用于瞬时单位线参数更新的递归公式,并研究了参数更新次数对流域地面径流模拟精度的影响.递归方程的推导是针对地面径流过程线的2个主要特征值:洪峰流量和峰现时间,使模拟的洪峰流量和峰现时间尽量接近观测值.应用结果表明,递归公式能够获得比矩法更高的地面径流模拟精度;但应用递归公式的次数不能太多,当超过2次时,模拟精度反而会降低.分析原因认为,递归公式推导的原理,是使洪峰流量和峰现时间的模拟值尽量接近观测值,以它们之间偏离的程度来调整参数n、k的值,但对整个地面径流过程的模拟精度的评判需要考虑整个地面径流过程,而不仅仅是洪峰流量和峰现时间,这是更新次数不应过多的原因.When instantaneous unit hydrograph （IUH） is used for simulating the direct runoff from the net rainfall over a catchment, two parameters need to be calibrated first： number of linear reservoirs n; and the storage-discharge coefficient K of each linear reservoir. The traditional calibration method is moment method. However, research results revealed that, the simulation results obtained from the IUHs calibrated by the mo- ment methods were not satisfactory, an updating on the calibrated parameters is necessary. Therefore, this paper brought out a recursive equation for updating the parameters of the IUH, and studied the effect of the updating numbers on the simulation results of the direct runoffs. The derivation of the recursive equation fo- cuses on the two major characteristics of the direct runoff courses： peak discharge and the time to peak. The effort was to try to obtain simulated peak discharge （and the time to peak） as close as possible to that of the observed ones. The results show that, for the case study applied in this research, higher simulation results （measured in terms of the index of agreement） were obtained when the recursive equation was applied to compare that not applied. However, the application number of the recursive equation was found to shall not be too many. If it is exceeding two times, the simulation accuracy will be decreased. The reason is that, the re- cursive equation was designed to enable the simulated peak discharge and the time to peak to be as close as possible to the observed ones; by changing the n and k values recursively. However, the criteria that justify the simulation results of the runoffs are much more than the peak discharge and the time to peak, which need to consider the complete courses of the runoff processes. The difference between the principle of the recursive equation and the criteria of runoff simulation accuracy suggests that the parameter updating should be carried out cautiously from being too much.

关 键 词：瞬时单位线 参数率定 更新 递归公式 

分 类 号：P339[天文地球—水文科学]