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	An adaptive approach to selecting a flow-partition exponent for a multiple-flow-direction algorithm
	Yang L.; Pei T.
	2007
关键词	digital elevation model (DEM) multiple flow direction algorithm (MFD) terrain analysis flow accumulation geographic information system (GIS) digital elevation models catchment-area drainage networks topographic index topmodel prediction
英文摘要	Most multiple-flow-direction algorithms (MFDs) use a flow-partition coefficient (exponent) to determine the fractions draining to all downslope neighbours. The commonly used MFD often employs a fixed exponent over an entire watershed. The fixed coefficient strategy cannot effectively model the impact of local terrain conditions on the dispersion of local flow. This paper addresses this problem based on the idea that dispersion of local flow varies over space due to the spatial variation of local terrain conditions. Thus, the flow-partition exponent of an MFD should also vary over space. We present an adaptive approach for determining the flow-partition exponent based on local topographic attribute which controls local flow partitioning. In our approach, the influence of local terrain on flow partition is modelled by a flow-partition function which is based on local maximum downslope gradient (we refer to this approach as MFD based on maximum downslope gradient, MFD-md for short). With this new approach, a steep terrain which induces a convergent flow condition can be modelled using a large value for the flow-partition exponent. Similarly, a gentle terrain can be modelled using a small value for the flow-partition exponent. MFD-md is quantitatively evaluated using four types of mathematical surfaces and their theoretical 'true' value of Specific Catchment Area (SCA). The Root Mean Square Error (RMSE) shows that the error of SCA computed by MFD-md is lower than that of SCA computed by the widely used SFD and MFD algorithms. Application of the new approach using a real DEM of a watershed in Northeast China shows that the flow accumulation computed by MFD-md is better adapted to terrain conditions based on visual judgement.
出处	International Journal of Geographical Information Science
卷	21
期	4
页	443-458
收录类别	SCI
语种	英语
ISSN号	1365-8816
内容类型	SCI/SSCI论文
源URL	[http://ir.igsnrr.ac.cn/handle/311030/23180]
专题	地理科学与资源研究所_历年回溯文献
推荐引用方式 GB/T 7714	Yang L.,Pei T.. An adaptive approach to selecting a flow-partition exponent for a multiple-flow-direction algorithm. 2007.

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