DEM栅格分辨率对TOPMODEL模拟不确定性的影响研究

The Impact of DEM Resolution on TOPMODEL Simulation Uncertainty

选择南水北调水源区所在的汉江流域的3个不同地貌类型的子流域为试验流域,采用1:5万比例尺DEM为基准数据,基于以地形为基础的半分布式流域水文模型TOPMODEL,研究栅格分辨率对水文模拟不确定性的影响,并利用多目标模糊优化算法,对水文模拟的不确定性进行了综合评价。结果表明,DEM栅格分辨率对地形特征和地形指数都有很大的影响,从而影响水文模拟的不确定性,但由于水文模拟的复杂性在一定程度上掩盖了不同DEM分辨率计算的地形指数的差别,使得这种影响不是很大。对于现有试验流域而言,当分辨率为200 m的时候可以得到相对较优的不确定性预测区间。

The hydrological uncertainty is one of the most important aspects in hydrological science research. This paper focuses on how resolution impacts the hydrological uncertainty using the TOPMODEL model based on the topographic index, which extracts from DEMs of different resolutions in the Hanjiang River. Three geomorphologic areas are selected as test areas, representing different terrain types from smooth to rough. Their DEMs are produced from digitizing contours of 1：50000 scale topographical maps. Hydrological uncertainty was assessed synthetically by using the multiple-objectives fuzzy optimal method. It is found from the analysis on different spatial resolutions that the topographic characteristics parameters of river basin are affected by DEM resolution remarkably, so as to affect the hydrological uncertainty, but this effect is not very great due to the hydrological complexity, and 200 m should be the more suitable grid size for hydrological uncertainty in this area. The integrated method of assessing hydrological uncertainty is a new throughway to study the various hydrological uncertainties.