• 关键词：格网尺度  AnnAGNPS模型  小尺度流域  地形参数  泥沙输出  径流

• 基金项目：“十一五”国家科技支撑计划资助项目(No.2006BAD03A13,2006BAD03A07)

• 田耀武
• 1. 中山大学生命科学学院, 广州 510275; 2. 中国林业科学研究院森林生态环境与保护研究所国家林业局森林生态环境重点实验室, 北京 100091

• 黄志霖
• 中国林业科学研究院森林生态环境与保护研究所国家林业局森林生态环境重点实验室, 北京 100091

• 曾立雄
• 中国林业科学研究院森林生态环境与保护研究所国家林业局森林生态环境重点实验室, 北京 100091

• 肖文发
• 中国林业科学研究院森林生态环境与保护研究所国家林业局森林生态环境重点实验室, 北京 100091

• 马德举
• 秭归县林业局, 宜昌 443600

• 摘要：为了解流域地形空间参数和其它参数的精度对农业非点源污染模型AnnAGNPS预测准确性的影响,利用三峡库区黑河小流域观测资料校准了AnnAGNPS模型,分析了1.5～12.5m格网尺度DEM对地形参数和模型负载输出的影响.结果表明,1.5～12.5m格网尺度DEM对流域径流量、洪峰流量、总N输出影响不显著,但对泥沙、总P、有机碳输出影响显著.三峡库区类似小流域宜采用5m格网尺度DEM,AnnAGNPS模型较不适合于尺度较小、坡度较大的小流域泥沙负载预测.

• Abstract：The input of nutrients from agricultural non-point sources(AGNPSs),sediment delivery and worsening of water quality have become challenging issues threatening water security,human health and natural ecosystems in the Three Gorges Reservoir area.The agricultural non-point source(AGNPS)model is a useful tool for analysis of agricultural watershed management scenarios.The accuracy of agricultural nonpoint source pollution models depends to a great extent on how well model input spatial parameters describe the relevant characteristics at the watershed scale.The objectives of this study were to define appropriate model input parameters and to define a protocol for model validation at the sub-watershed and watershed scale in the Three-Gorges Reservoir area.The precision of spatial input parameters affects the simulation results of runoff and sediment yield from the watershed.This study integrated AnnAGNPSand digital databases to simulate the impact of DEMmesh size change(from 1.5 to 12.5 m)on runoff,sediment,and nutrient yields based on available datasets at the outlet of a small-scale agricultural watershed(144.4 hm²).For tested mesh sizes,the simulation results showed that the computed runoff flux,peak flow and total nitrogen export were not likely to be significantly affected,while estimates of sediment yields,total phosphorus and total organic carbon export in runoff water were significantly affected.These results indicated that DEMof 5 m mesh size was well suited to applications for model simulation in the small watershed;however,AnnAGNPSwas less reliable for sediment loading prediction in a similar-sized hilly watershed in the Three Gorges Reservoir area.

• Key words：DEM mesh size  AnnAGNPS model  small-scale watershed  topographic parameter  sediment transport  runoff

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