辽河流域径流过程模拟的空间尺度效应分析

针对分布式水文模型的尺度问题,在辽河流域,采用SWAT模型,研究不同DEM分辨率及不同子流域大小导致模拟结果的不确定性。研究结果表明:①DEM分辨率对流域平均高程、流域面积和子流域数量影响较小,而对流域平均坡度有显著的影响,因此径流模拟时需要进行坡度订正。对于河网提取,DEM分辨率为500m时提取的河网与基准河网吻合程度较高。②子流域面积过大,数量过少时,模拟结果与基准结果偏差较大,而在划分一定阈值波动范围内径流对子流域数量敏感性较低。

Spatial Scale Analysis of Runoff Simulation for Liaohe River Basin

Distributed models emphasize specific physical mechanism, then the input and parameters become more complex, manyproblems such as different parameters have same effect and which scale is proper, lead to uncertainty of simulated results. As forthe choice of scale, based on SWAT model and choosing Liaohe watershed as study area, this paper analysed two influencing fac -tors on estimated runoff, which include different DEM resolutions and different subbasion divisions. The results show that, 1) DEMresolution has little effect on watershed mean altitude, watershed area and subbasin number, but has much effect on mean slope,which means that when estimate runoff, we should make slope correction. As for river network, results showed when DEM resolutionis 500m, the watershed delineation is much more similar with actual river network. 2) When the quantity of subbasin divisions islittle, the estimated runoff varied considerably with the based runoff and had a sensitivity interval. This research will have muchsignificance in the development and application of distributed models.