Effect of DEM mesh size on AnnAGNPS simulation and slope correction
Effect of DEM mesh size on AnnAGNPS simulation and slope correction
复制标题
DEM 网格尺寸对 AnnAGNPS 模拟和坡度校正的影响
DOI：
10.1007/s10661-010-1734-7
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发表时间：
2011-08
影响因子：
3
通讯作者：
Lin, Q.
中科院分区：
文献类型：
--
作者：
Wang, Xiaoyan;Lin, Q.
本文的目的是研究流域尺度的年化农业非点源污染 (AnnAGNPS) 模型模拟中数字高程模型 (DEM) 的网格大小对地形属性的影响，并为低分辨率 DEM 提供坡度梯度修正。通过比较八个 DEM（30、40、50、60、70、80、90 和 100 m），检查了不同网格大小的 DEM 对地形属性的影响。评估了 AnnAGNPS 对径流、沉积物和养分负荷刺激的准确性。结果如下：（1）随着DEM分辨率的降低，Rnoff变化不大，而土壤侵蚀和总氮（TN）负荷变化显着。使用调整后的 50 m DEM 修正坡度对 AnnAGNPS 建模的径流模拟几乎没有影响。 (2) 随着 DEM 网格尺寸从 30 增加到 60 m，产沙量和总氮负荷降低； DEM 网格尺寸大于 60 m 时，沉积物和 TN 负荷略有减少。总磷 (TP) 变化也有类似的趋势，但变化范围较小，沉积物、TN 和 TP 的模拟增加，其中沉积物与使用未调整的 50 m DEM 的模型相比增加了 1.75 倍。总而言之，修正后的模拟结果与使用 30 m DEM 的结果仍然存在较大差异。 AnnAGNPS 对于小丘陵流域的泥沙负荷预测不太可靠。 (3)DEM分辨率对坡度影响显着。随着DEM精度的降低，各种DEM的坡度平均值、最小值、最大值明显减小。对于0∼15°的坡度，较低分辨率DEM的斜率通常大于较高分辨率DEM的斜率。但对于大于 15° 的坡度，较低分辨率 DEM 下的斜率通常小于较高分辨率 DEM 下的斜率。因此需要通过拟合方程来调整斜率。三次模型用于校正从较低分辨率到较高分辨率的斜率梯度。 Dage 流域的结果表明，即使将 50 m DEM 的斜率调整为与 30 m DEM 的斜率更相似，也需要使用细网格来避免大幅低估沉积物和总氮负荷以及适度低估总磷负荷。将网格尺寸减小到超过此阈值不会对计算的径流通量产生实质性影响，但会产生氮和沉积物产量的预测误差。因此，适当的 DEM 将控制误差并使模拟处于可接受的水平。
The objective of this paper is to study the impact of the mesh size of the digital elevation model (DEM) on terrain attributes within an Annualized AGricultural NonPoint Source pollution (AnnAGNPS) Model simulation at watershed scale and provide a correction of slope gradient for low resolution DEMs. The effect of different grid sizes of DEMs on terrain attributes was examined by comparing eight DEMs (30, 40, 50, 60, 70, 80, 90, and 100 m). The accuracy of the AnnAGNPS stimulation on runoff, sediments, and nutrient loads is evaluated. The results are as follows: (1) Rnoff does not vary much with decrease of DEM resolution whereas soil erosion and total nitrogen (TN) load change prominently. There is little effect on runoff simulation of AnnAGNPS modeling by the amended slope using an adjusted 50 m DEM. (2) A decrease of sediment yield and TN load is observed with an increase of DEM mesh size from 30 to 60 m; a slight decrease of sediment and TN load with the DEM mesh size bigger than 60 m. There is similar trend for total phosphorus (TP) variation, but with less range of variation, the simulation of sediment, TN, and TP increase, in which sediment increase up to 1.75 times compared to the model using unadjusted 50 m DEM. In all, the amended simulation still has a large difference relative to the results using 30 m DEM. AnnAGNPS is less reliable for sediment loading prediction in a small hilly watershed. (3) Resolution of DEM has significant impact on slope gradient. The average, minimum, maximum of slope from the various DEMs reduced obviously with the decrease of DEM precision. For the grade of 0∼15°, the slopes at lower resolution DEM are generally bigger than those at higher resolution DEM. But for the grade bigger than 15°, the slopes at lower resolution DEM are generally smaller than those at higher resolution DEM. So it is necessary to adjust the slope with a fitting equation. A cubic model is used for correction of slope gradient from lower resolution to that from higher resolution. Results for Dage watershed showed that fine meshes are desired to avoid large underestimates of sediment and total nitrogen loads and moderate underestimates of total phosphorus loads even with the slopes for the 50 m DEM adjusted to be more similar to the slopes from the 30 m DEM. Decreasing the mesh size beyond this threshold does not substantially affect the computed runoff flux but generated prediction errors for nitrogen and sediment yields. So the appropriate DEM will control error and make simulation at acceptable level.
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影响因子：
2.4
作者：
S. Kienzle
通讯作者：
S. Kienzle
影响因子：
2.5
作者：
Shuo-sheng Wu;Lynn Usery;Michael P. Finn;D. Bosch
通讯作者：
Shuo-sheng Wu;Lynn Usery;Michael P. Finn;D. Bosch
DOI：
10.1016/j.cageo.2007.05.003
发表时间：
2007-10
期刊：
Comput. Geosci.
影响因子：
--
作者：
S. Wise
通讯作者：
S. Wise
影响因子：
3.2
作者：
P. Quinn;K. Beven;P. Chevallier;O. Planchon
通讯作者：
P. Quinn;K. Beven;P. Chevallier;O. Planchon
DOI：
10.1061/(asce)0733-9496(1993)119:2(141
发表时间：
1993-03
影响因子：
3.1
作者：
B. Vieux;Scott Needham
通讯作者：
B. Vieux;Scott Needham