非均匀土壤区域SVAT模型中土壤水动力学参数的整合研究

荷兰Cabauw地区一个 10km10km区域内的四种主要土壤的水动力学参数用一种实验室直接测定法 (Wind氏蒸发法 )和两种间接方法 (分段土壤推导函数、连续土壤推导函数)确定 ,而该区域水动力学特性参数的整合则采用两组方案 (聚合土壤参数法和有效土壤参数法 )进行。一个SVAT模型的模拟输出结果感热通量、潜热通量与实测数据的比较分析表明 :(1)对于用分段土壤推导函数确定的土壤水动力学参数的区域整合 ,以逆模拟法(有效土壤参数法 )较为可行 ,其模拟感热、潜热的精确性接近参比方案 (模拟 平均法) ;(2 )对于实验室直接测定的参数 ,则以几何平均vanGenuchten Mualem经验公式参数的方案 (聚合土壤参数法 )为佳 ;(3)对于连续土壤推导函数推导的水动力学参数 ,几何平均土壤组分方案 (聚合土壤参数法 )和逆模拟法方案 (有效土壤参数法 )二者均可得到优于参比方案 (模拟 平均法)的模拟结果 ,其中以前者最佳 ;(4 )所有区域化参数整合方案中 ,以水平几何平均区域内实验室直接测定的参数的方案最优 ;同时 ,连续土壤推导函数法的土壤组分几何平均方案的模型输出精确性接近该最优方案

Integration of soil hydraulic characteristic parameters for SVAT model in a heterogeneous soil region: A case study

This case study compared two kinds of integrating schematization of soil hydraulic characteristic parameters for a SVAT model?SWAPS in a heterogeneous soil region?Cabauw location in the western plain of the Netherlands. The schematization included aggregating soil parameterization and inverse modeling method, which resulted in two sets of parameters, aggregating soil parameters and effective soil parameters, respectively. The van Genuchten?Mualem model parameters of 4 typical soil profiles in the objective region were determined by direct laboratory method (Wind's Evaporation Method) and two indirect methods (Class PTF and Continuos PTF). Statistical Analysis of the validation and simulation data sets of sensible heat flux and latent heat flux indicated that: (1) for soil hydraulic characteristics from Class PTF, inverse modeling method (effective soil parameterization) could be available to integrate regional soil parameters in modeling partition of available surface energy flux; (2) for individual parameters determined by Wind's method, the schematization by areal averaging van Genuchten-Mualem model parameters (aggregating soil parameterization) could obtain the most accuracy output of partitioning of available surface heat flux; and (3) for soil hydraulic parameters derived from Continuous PTF, both averaging soil component (aggregating soil parameterization) and inverse modeling method (effective soil parameterization) could be available to integrate regional soil parameters, while the former showed better results. Among the studied schematizations for modeling sensible and latent heat flux, areal averaging van Genuchten-Mualem model parameters from Wind's method only horizontally was the best. Meanwhile aggregating soil components in great detail to derive the relevant parameters in the model showed good accuracy nearly as it. It means that the latter schematization could have potential utility to determine regional soil hydraulic parameters for SVAT model due to not only its accuracy but also its little cost both in money and time when available.