基于分布式水文模型的流域输沙过程模拟

Sediment Yield Simulation Based on Distributed Hydrologic Model in the Mesoscale Watershed

根据黄土丘陵沟壑区藉河流域1962—2008年的逐日水文、气象资料,建立了空间数据库和属性数据库,采用分布式水文模型SWAT对该区过去近50年的输沙变化进行了模拟和验证.结果表明,年均输沙量在校准期与验证期内的模拟值和实测值保持比较一致的趋势性变化,但验证期的模拟效果不如校准期的;月均输沙量在校准期模拟值和实测值的相对误差Re、决定系数R2、效率系数Ens分别为7.5%,0.862,0.764,验证期内则分别为8.9%,0.535,0.474,模型验证效果不太好,类似于年均输沙量模拟,且月均输沙量的模拟效果不如年均输沙量的.

Daily hydrologic and meteorological data from 1962 to 2008 in Jibe watershed of the loess hilly and gully region were used to establish spatial and attributive databases. The SWAT model was used to simulate and verify the sediment yield changes during the past 50 years. The results showed that, in the calibration and validation periods, for annual average sediment yield, the simulated values and the observed values kept accordant trends, however, the performance in the validation period was not better than that in the calibration period; with regard to monthly sediment yield, relative error Re, determination coefficient R2 , and efficiency coefficient Ens in the calibration period were 7.5% , 0. 862, 0. 764 respectively, while they were 8.9% , 0. 535 and 0. 474 reslSectively in the validation period, and it was similar to annual sediment yield simulation. Moreover, it was found that monthly simulation performance was not better than annul simulation.