TOPMODEL模型首要也是关键的问题就是地形指数的计算问题。除计算方法外,地形指数的分布还与DEM网格尺度息息相关。较大的网格推出的地形指数不具有显示水流路径的物理含义,会丢失一些物理信息。太细的分辨率可能引起流向和坡度的混乱,导致水流路径不连续。对于流域尺度而言。合适的网格尺度在很大程度上影响模拟结果的精度,但目前关于这方面的研究却很少。本文在集水面积5340km^2的中尺度潮河流域上进行地形分析计算,深入的分析了从50m~600m以50m为间隔的不同网格尺度对地形指数分布的影响。并以平水年为例。研究了这些地形指数对流域径流模拟的影响。得出的结论对于TOPMODEL模型在中尺度流域上的应用具有指导意义。
It is important for TOPMODEL to calculate topographic indexes. Distribution of topographic indexes is concerned with DEM mesh scale. The topographic indexes obtained from larger scale meshes have not physical significance, at which some physical.information will be lost. On the other hand, fine scales may result in discontinuous flow pathways. Appropriate mesh scale is very influential on appalling TOPMODEL at basin scale. The concerned study was made with the Chaohe River Basin as a case, a moderate catchment of 5340 km^2 in which the impact of different scales on distribution of topographic indexes was analyzed, and influence of these indexes on runoff simulation was studied. The conclusion can provide a thoughtful approach for applying TOPMODEL in moderate catchments.