考虑植被根系深度动态变化的VIC径流模拟模型

VIC model for runoff simulation considering dynamic changes of vegetation root depth

为了提高干旱半干旱地区植被变化影响下的水文模型模拟精度,结合植物根系的垂直分布与气候、土壤条件,提出了基于流域气象和土壤性质等下垫面特征的流域根系平均深度估算方法,以黄土高原地区无定河流域为例,构建了考虑植被根系深度动态变化的可变下渗容量(VIC)径流模拟模型(VIC-DR模型)。将该模型径流模拟结果与有汇流演算的VIC模型(VIC-R模型)结果进行比较。结果表明:与VIC-R模型相比,VIC-DR模型模拟精度显著提高,VIC-DR模型对无定河流域月尺度、日尺度径流量模拟结果的纳什效率系数分别提高了10.6%和8.7%,相对误差分别下降了15.4%和5.1%,与实测值相关系数均大于0.6;VIC-DR模型的模拟结果符合流域实际情况,模型适用性良好。

In order to improve the simulation accuracy of the hydrological model under the influence of vegetation change in arid and semi-arid areas,combing with the vertical distribution of plant roots and climate and soil conditions,a method for estimating average root depth in a basin based on underlying surface characteristics such as basin meteorology and soil properties was proposed.With the Wuding River Basin in Loess Plateau region used as an example,a variable infiltration capacity(VIC)model for runoff simulation,considering dynamic changes of vegetation root depth,named VIC-DR model,was constructed.The runoff simulation results of the VIC-DR model were compared with those of the original VIC model with the confluence checking computation,named VIC-R model.The results show that,compared with the VIC-R model,the simulation accuracy of the VIC-DR model was significantly improved.The Nash-sutcliffe efficiency coefficient of the monthly and daily runoff simulation results of the VIC-DR model increased by 10.6%and 8.7%,respectively,the relative error decreased by 15.4%and 5.1%,respectively,and the correlation coefficients between the simulated runoff and measured runoff at monthly scale and daily scale were greater than 0.6.The simulation results of the VIC-DR model accord with the actual situation of the basin,and the model has high applicability.