数字高程模型不确定性对地形参数和TOPMODEL的影响

数字高程模型(Digital Elevation Model,DEM)是基础数据,数据本身不可避免地存在不确定性.不确定性会随着传播而累积,从而影响DEM应用结果的可靠性.从DEM不确定性传播的角度,利用蒙特卡罗模拟技术研究了DEM不确定性传播对坡度、上坡集水面积、地形指数和TOPMODEL模型的影响,发现DEM不确定性传播对坡度、上坡集水面积和地形指数有一定的影响,对上坡集水面积影响最大,对地形指数影响最小;但DEM不确定性传播对TOPMODEL模型影响甚微.

Research on effects of DEM uncertainty on topographic parameters and TOPMODEL

DEM(Digital Elevation Model) is the digital representation of earth surface,which is used for enormous applications.Generally,DEM is employed without the analyses of its effects of both uncertainty and propagations on specific applications.In this paper,the effects of DEM uncertainty on the selected topographic parameters,such as the slope,upslope contributing area,the topographic index and TOPMODEL hydrological model,are analyzed in terms of the DEM uncertainty propagation.Furthermore,the effects of DEM uncertainty propagation on three topographic parameters are evaluated by using the simulation method of Monte Carlo,and then the effects of DEM uncertainty propagation on TOPMODEL is analyzed in the quantitative and qualitative aspects.This research shows that DEM uncertainty propagation almost certainly affects the slope,upslope contributing area and the topographic index as well.Among all of them,its effect on upslope contributing area is the biggest; while on the topographic index is the smallest.However,the effect of DEM uncertainty propagation on TOPMODEL is trivial and could be ignored in the applications.Further,the reasons can be found that on the one hand,the TOPMODEL is not sensitive to the distribution of topographic index; and on the other hand,the topographic index is affected limitedly by DEM uncertainty propagation.