地形演化模型的参数敏感性分析:以库玛拉克河流域为例  

Parameter Sensitivity Analysis of Landscape Evolution Models-An Example from the Kumarak River Basin

作　　者：吴奇辉 曾献奎[1] 吴吉春[1] WU Qihui;ZENG Xiankui;WU Jichun(School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,China)

机构地区：[1]南京大学地球科学与工程学院,南京210023

出　　处：《高校地质学报》2024年第5期585-592,共8页Geological Journal of China Universities

基　　金：国家自然科学基金项目(42072272)资助。

摘　　要：地形演化模型是进行地形演化定量研究的基础,其涉及过程复杂、模型参数众多,为缓解参数识别困难和提高模型参数设置的可靠性,识别地形演化模型的关键驱动机制和参数成为当前研究的重点。该研究选择新疆塔里木河流域的库玛拉克河流域为研究区,基于LE-PIHM(Landscape Evolution-Penn State Integrated Hydrologic Model)建立了研究区地形演化模型,通过全局敏感性分析方法—Sobol方法,识别了LE-PIHM模型的参数敏感性。以研究区内三个典型地貌类型的地表高程为敏感性分析的目标函数,结果表明,研究区山区地形演化的关键模型参数为裸露基岩的风化速率(P0)、基岩风化方程拟合系数(α)和构造抬升速率(U),这些参数主要涉及基岩风化作用和构造抬升作用。同时,在研究区的平原区,除含水层孔隙度(ng)以外,模型参数均具有较高的敏感性,平原区高程变化主要由各参数之间的相互作用控制。在研究区的河道地区,模型参数敏感性与在平原区类似,但土壤孔隙度(ns)和含水层水平渗透系数(KHg)有显著更强的敏感性,其分别涉及地表水—地下水交互作用和含水层透水性能。Landscape evolution model is the basis for quantitative research on landscape evolution,but it involves complex processes and numerous model parameters.In order to alleviate the difficulty of parameter identification and improve the reliability of model parameter setting,identifying the key driving mechanisms and parameters of the landscape evolution model has become the focus of current research.In this study,the Kumarak River Basin in the Tarim River Basin of Xinjiang was selected as the study area,and the landscape evolution model of the study area was established based on the LE-PIHM(Landscape Evolution-Penn State Integrated Hydrologic Model).The parameter sensitivities of the LE-PIHM model were identified by the global sensitivity analysis method,Sobol method.The surface elevation of three typical landforms in the study area was used as the objective function for the sensitivity analysis,and the results showed that the key model parameters for the landscape evolution of the mountainous areas in the study area were the weathering rate of bare bedrock(P0),the fitting coefficient for bedrock weathering equation(α)and the rate of tectonic uplift(U),which were mainly related to the weathering effect of the bedrock and the tectonic uplift effect.Meanwhile,in the plain area of the study area,the model parameters have high sensitivity except for aquifer porosity(ng),and the elevation change in the plain area is mainly controlled by the interaction between the parameters.In the riverine area of the study area,the sensitivity of the model parameters is similar to that in the plain area,but the soil porosity(ns)and aquifer horizontal hydraulic conductivity(KHg)have significantly stronger sensitivities,which are related to surface watergroundwater interactions and aquifer permeability properties,respectively.

关 键 词：地形演化模型 Sobol方法 敏感性分析 高程变化 

分 类 号：P641[天文地球—地质矿产勘探]