基于不同分辨率DEM提取坡度值的转换关系研究  

Study on conversion relationship of slope information extracted from different resolution DEM

作　　者：王英[1] 龚家国[1] 贾仰文[1] 王浩[1] WANG Ying;GONG Jiaguo;JIAYangwen;WANG Hao(State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower Research,Beijing100038,China)

机构地区：[1]中国水利水电科学研究院流域水循环模拟与调控国家重点实验室

出　　处：《水利水电技术》2019年第8期45-51,共7页Water Resources and Hydropower Engineering

基　　金：国家重点研发计划课题(2018YFC0506904);国家重点基础研究发展计划“973”(2015CB452701);国家自然科学基金项目(51209222)

摘　　要：基于DEM提取计算单元坡度是分布式水文模型构建的重要手段之一,通过研究不同分辨率DEM对WEP-L模型计算单元坡度的影响及其转换关系,为模型计算中坡度与其他运算量之间非线性关系带来的计算精度与计算效率之间的矛盾提供解决方案。以NASA发布的30 m分辨率DEM数据为基础,以不同尺度流域(南小河沟流域,面积36.3 km^2;泾河流域,面积4.5万km^2)为研究对象,利用分形结合半方差函数的方法分析低分辨率DEM提取的计算单元坡度向高分辨率DEM提取的坡度信息转换的规律。研究发现以30 m分辨率DEM为基础提取的子流域套等高带结构能够很好地反映南小河沟流域地形"坡度等高分布"的特点;利用分形结合半方差函数的形式能够有效地实现基于低分辨率DEM提取的流域基本计算单元坡度向"真实"地形坡度值转换。根据模型计算需求,给出了不同分辨率DEM数据提取坡度值的转换关系。本研究可为分布式水文模型搭建面临的计算精度与计算效率矛盾问题提供借鉴和参考。DEM(digital elevation model)-based extraction of the slope calculation unit is one of the important means to construct distributed hydrological model. Through studying the influence from different resolution DEM on the slope calculation unit of WEP-L(water and energy transfer process in large river basins) model and the relevant conversion relationship, a scheme is provided for solving the contradiction between the calculation accuracy and the calculation efficiency brought from the non-linear relationship between slope and other computational loads in model calculation. Based on the DEM data with the resolution of 30 m released by NASA(National Aeronautics and Space Administration), the law of the information conversion from the slope calculation unit extracted from low-resolution DEM to that from high-resolution DEM is analyzed with the method of the fractal theory combined semi-variance function by taking the watersheds of different scales(Nanxiaohegou Watershed with the area of 36.3 km^2;Jinghe Watershed with the area of 45 000 km^2) as the study objects. The study finds out that the characteristics of the slope contour distribution of the terrain of Nanxiaohegou Watershed can be better reflected by the contour zone structures of the sub-watershed set extracted on the basis of the DEM with the resolution of 30 m, while the conversion from the basic slope calculation unit of watershed extracted in accordance with low-resolution DEM to the value of the real slope of terrain can be effectively realized with the method of the fractal theory combined semi-variance function. According to the demand of the model calculation, the conversion relationship among the slope values extracted from the DEM data with different resolutions are given out. This study can provide reference for solving the contradiction between calculation accuracy and calculation efficiency faced during constructing distributed hydrological model.

关 键 词：坡度 DEM WEP-L模型 分布式水文模型 

分 类 号：P333.9[天文地球—水文科学] TP79[水利工程—水文学及水资源]