流向是地形分析中的重要内容之一,在分布式水文模型等研究中起着重要作用。文章提出基于局部地表形态的多流向算法,即对每一个DEM栅格,在以其为中心的3×3窗口中进行局部地形分析,确定基于随坡度和过水宽度而变化的水流分配系数。该方法被应用在实际数字地形模型上,并以汇水面积和比汇水面积为研究指标,与目前流行的D8、Dinf等算法进行了相似性分析。结果表明,该方法能够获得更为符合实际的水流汇集的空间分布。
It is one of the important contents in the topography analysis as well as in the hydrological distribution models that how to determine flow directions of water in each cell of DEM.Although many hydrologists have already put forward a lot of different flow direction algorithms over the past dozens of years.A new approach of assigning flow directions of DEM cell is proposed in this study, which is called local topography-based variable flow width method.This approach is based on the analysis of the local topography formation defined within a 3?3 cell window with the recognition that the flow distribution coefficient for each flow direction is changeable with the corresponding slope and outflow width.In the paper, this method has been tested on the digital topography of an actual watershed.Two indices, the total catchment area (TCA) and specific catchment area (SCA), produced by four flow routing algorithms including the D8 (eight flow directions), Dinf (an infinite number of possible single flow directions), MS (multiple flow directions based on slope) and the local topography-based variable flow width method, are selected to compare and analyze efficiencies of those four algorithms.The result shows that the local topography-based variable flow width method can obtain more reasonable spatial distribution of water accumulation, compared with the D8, Dinf, and MS.
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