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为合理地研究资料匮乏的高寒山区水文规律、提高融雪径流模拟的精度,以地形复杂且站点稀少的喀什河流域为例,基于DEM不同分辨率(30m×30m、90m×90m、200m×200m、400m×400m、600m×600m和1 000m×1 000m)构建了SWAT模型,探讨了不同分辨率DEM的差异性及DEM分辨率对河流径流模拟精度的影响。结果表明,随着DEM分辨率的降低,流域地形变缓,流域总面积、高程区间及平均坡度逐渐减小,进而影响到径流模拟的结果;随着DEM分辨率的降低,模型整个模拟期的Nash-Sutcliffe效率系数大致呈逐渐减小趋势,相对误差大致呈逐渐增大趋势,说明低精度的DEM所带来的误差,会导致径流峰值降低,洪峰衰减,从而使模拟出的径流量和实测径流值存在偏差,因此喀什河流域最优的DEM分辨率为90m×90m。
In order to study the hydrological law of alpine mountainous area lacking in data and improve the accuracy of snowmelt runoff simulation, taking the Kashi River basin with complex terrain and few sites as an example, based on different resolution of DEM (30m × 30m, 90m × 90m, 200m × 200m, 400m × 400m, 600m × 600m and 1 000m × 1 000m), the SWAT model was constructed and the effects of DEM resolution and DEM resolution on river runoff simulation accuracy were discussed. The results show that with the decrease of DEM resolution, the watershed decelerates slowly, and the basin total area, elevation interval and average gradient gradually decrease, which affects the result of runoff simulation. With the decrease of DEM resolution, The efficiency coefficient of Nash-Sutcliffe roughly decreases gradually, and the relative error increases gradually. It shows that the error caused by low-precision DEM will lead to the decrease of peak flow and attenuation of flood peak, so that the simulated runoff and measured Because of the deviation of runoff, the optimal resolution of DEM in Kashgar basin is 90m × 90m.