An Assessment of the Effects of Cell Size on AGNPS Modeling of Watershed Runoff
An Assessment of the Effects of Cell Size on AGNPS Modeling of Watershed Runoff
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DOI：
10.1559/152304008786140542
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发表时间：
2008-01
影响因子：
2.5
通讯作者：
Shuo-sheng Wu;Lynn Usery;Michael P. Finn;D. Bosch
中科院分区：
文献类型：
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作者：
Shuo-sheng Wu;Lynn Usery;Michael P. Finn;D. Bosch
本研究探讨了模拟流域径流的变化，从农业非点源（AGEARS）污染模型作为一个功能的模型输入单元大小分辨率为8个不同的单元大小（30米，60米，120米，210米，240米，480米，960米，和1920米）的小河流域（格鲁吉亚，美国）。研究了不同单元格大小和趋势的地表单元径流（面积加权单元径流）、总径流量、聚类统计和热点模式。总径流量随单元尺寸的增大而减小。使用210米或更小的单元格大小的数据集，结合一个有代表性的流域边界允许一个模型的径流量在0.2%的精度。径流聚类统计随着单元格大小的增加而减少; 960 m或更小的单元格大小需要指示显著的高径流聚类。径流热点区域有一个减少的趋势，增加单元大小;一个单元大小为240米或更小的检测重要的热点。由于径流量随单元大小的变化不一致，单元大小对径流量影响的结论不适用于局部流域;但由于趋势一致，聚类和热点分析的最佳单元大小适用于局部流域。
This study investigates the changes in simulated watershed runoff from the Agricultural NonPoint Source (AGNPS) pollution model as a function of model input cell size resolution for eight different cell sizes (30 m, 60 m, 120 m, 210 m, 240 m, 480 m, 960 m, and 1920 m) for the Little River Watershed (Georgia, USA). Overland cell runoff (area-weighted cell runoff), total runoff volume, clustering statistics, and hot spot patterns were examined for the different cell sizes and trends identified. Total runoff volumes decreased with increasing cell size. Using data sets of 210-m cell size or smaller in conjunction with a representative watershed boundary allows one to model the runoff volumes within 0.2 percent accuracy. The runoff clustering statistics decrease with increasing cell size; a cell size of 960 m or smaller is necessary to indicate significant high-runoff clustering. Runoff hot spot areas have a decreasing trend with increasing cell size; a cell size of 240 m or smaller is required to detect important hot spots. Conclusions regarding cell size effects on runoff estimation cannot be applied to local watershed areas due to the inconsistent changes of runoff volume with cell size; but, optimal cells sizes for clustering and hot spot analyses are applicable to local watershed areas due to the consistent trends.