• 论文 •

### 降雨的空间不均性对模拟产流量和产沙量不确定的影响

1. 北京师范大学水科学研究所水沙科学教育部重点实验室,北京100875
• 收稿日期:2003-06-01 修回日期:2003-08-01 出版日期:2003-09-24 发布日期:2003-09-24
• 作者简介:郝芳华(1963-),女,江苏连云港人,教授,主要从事水资源与水环境研究。
• 基金资助:

国家重点基础研究发展规划(973)项目(G1999043601);国家自然科学基金委员会、水利部黄河水利委员会黄河联合研究基金项目(50239010)

### Model Output Uncertainty Due to Spatial Variability of Rainfall

HAO Fanghua, CHEN Liqun, LIU Changming, ZHANG xuesong

1. Institute of Water Sciences,Beijing Normal University,100875,China
• Received:2003-06-01 Revised:2003-08-01 Online:2003-09-24 Published:2003-09-24

Abstract: Traditionally in the application of hydrologic/water quality (H/WQ) models, rainfall is assumed to be spatially homogeneous and is considered not to contribute to output uncertainty. The objective of this study was to assess the uncertainty induced by model outputs-runoff and sediment yield- solely due to rainfall spatial variability. The study was conducted using the SWAT model and the rainfall captured by a network of 24 rain gauges in Lushi Basin. For each rainfall event, the model was run using the rainfall captured by each rain gauge, one at a time, under the assumption of rainfall spatial homogeneity in the study area, A large uncertainty in the modeled outputs was resulted from the rainfall spatial variability. The uncertainty in the modeled outputs exceeded the input rainfall uncertainty. The uncertainty of simulated sediment yield outranges that of the runoff. The uncertainty of the simulated runoff increases with the spatial variability of rainfall. The more homogeneous of the rainfall, the more certainty of the modeled runoff. The uncertainty of the modeled sediment yield increased with the increase of spatial variability of rainfall, and the uncertainty of the modeled sediment yield is inversely related with the simulated sediment yield. Results of this study indicate that spatial variability of rainfall should be captured and used in H/WQ models in order to accurately assess the model outputs.In the application of H/WQ models, the assumption of the spatial homogeneity of the rainfall may not be valid. Spatial variability of rainfall introduces uncertainty into model outputs when uniformity of rainfall is assumed. Spatial variability of rainfall should be captured and used in H/WQ models in order to accurately assess the release and transport of pollutants. Since rainfall is a driving force behind many kinds of pollutant release and subsequent transport mechanisms, ignoring this property of rainfall in the application of H/WQ models will put a limit on the accuracy of the model results.

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