基于灵敏度分析的地下水数值模拟精度适应性评价

为了更好地刻画数值模型模拟精度对参数初值的依赖性,同时避免由于比较水位高低而存在的非标准化问题,分别将Nash-Sutcliffe效率系数Ens及平均相对误差Emr作为精度评价指标进行数值模型模拟精度的适应性评价.借助于灵敏度分析的Morris方法,对地下水模型参数中的渗透系数K和给水度μ进行了适应性评价和时间序列的灵敏度分析.结果表明:不同精度评价指标所得模型的优化参数不同,存在一定的差异;不同参数初值对于灵敏度分析影响明显;数值模型运行开始参数灵敏度较小,随着计算水位降深值的增大,其灵敏度值呈增加趋势.

Adaptability evaluation of numerical simulation accuracy of groundwater based on sensitivity analysis

In order to satisfactorily depict the dependence of simulation accuracy of mathematical models on the initial parameters and to avoid the non-standardization of water levels, the Nash-Sutcliffe efficiency coefficient Ens and average relative error Emr were taken as the evaluation indexes for evaluation of the adaptability of numerical simulation accuracy. Based on the Morris method, adaptability evaluation and sensitivity analysis of time series were performed on the parameters K and μ for the numerical simulation of groundwater. The results show that there are differences in the optimum parameters obtained using different adaptability indexes. Different initial parameters have significant influences on the results of the sensitivity analysis and the time series analysis. The parameter sensitivity is lesser at the initial stage of model operation, and with the increase of drawdown of the calculated water levels it exhibits an increasing tendency.