【摘要】 TOPMODEL是目前被广泛应用的半分布式流域水文模型,它以地形为基础的特点使得DEM的空间分辨率成为影响模型模拟结果准确性的重要参数。不同分辨率的DEM将计算出不同的地形指数ln(α/tanβ)分布,其作为TOPMODEL的地形参数直接影响着模型的模拟结果。以10 m分辨率的DEM为原始数据,生成10~1 000 m等17种分辨率的DEM,使用地形信息熵的概念,比较不同分辨率的DEM对地形信息提取的影响。假设TOPMODEL在10 m分辨率的DEM计算的流量过程线为观测值,对比了不同分辨率的DEM对流量过程线和Nash效率系数产生的变化。对于所研究的流域,150 m分辨率是建立TOPMODEL模型的最佳值,300 m分辨率是保证模型结果有效的基本要求。使用Monte Carlo方法计算TOPMODEL中参数对DEM分辨率的敏感性,指出在模型的5个参数中,只有饱和导水系数T0对DEM分辨率敏感。更多还原

【Abstract】 The digital elevation model(DEM) grid size has significant influence on topographic index,and the effects of topography on watershed hydrology are represented in the TOPMODEL as the distribution of topographical index ln(α/tanβ).In this study,the 10 m grid size is selected as the base resolution,and 17 DEMs are generated ranging from 10 m to 1000 m resolutions.The discharge of TOPMODEL in 10m grid is taken as the observed value compared with the discharges among different DEM resolutions.A significant change of the model in response to scale is identified with the grid size of 300 m,the efficiency remains approximately constant between 10m and 150 m,and above this scale the efficiency declines rapidly.In the last section of the study,the Monte-Carlo method is used to analyze the effects of DEM grid size on the five TOPMODEL parameters.More significant are the results of T0 which shows a strong positive relationship with the grid size increase and the other parameters perform have no clear influence.更多还原