基于VIC-3L的塔里木河流域源流区水文要素特征分析

ANALYSIS OF HYDROLOGICAL VARIABLES BASED ON THE VIC-3L MODEL IN HEADWATER CATCHMENT OF THE TARIM RIVER BASIN

基于不同分辨率,在塔里木河流域三源流区应用大尺度分布式水文模型VIC-3L,探讨人类活动对流域水文要素的影响,并分析不同模型分辨率对模拟结果的影响.结果表明模型在该地区应用效果基本满意,但灌溉期(4、5月份)的模拟流量明显高于实测值;模型在受人类活动影响较大区域模拟效果较差;阿克苏河中上游地区在三源流区内产流较高,而东部荒漠平原区产流量较低;阿克苏河下游、叶尔羌河中游以及和田河上游地区天然状态下耗水率较高,而东部荒漠平原区较低,且不易产流;模型在较低分辨率下模拟的径流总量和洪峰流量明显偏高.

A grid network version of the three-layer Variable Infiltration Capacity （VIC-3L） macroscale hydrological model was presented in this paper. The VIC-3L is a physically based soil-vegetation-atmosphere transfer scheme designed to represent the land surface in numerical weather prediction and climate models, which considers both infiltration excess and saturation excess runoff. The model was applied in the headwater catchment of the Tarim River basin to simulate monthly hydrographs. Then, the spatial and temporal distributions of main hydrological variables were analyzed. Both annual runoff volumes as well as hydrograph shape were simulated with an acceptable degree of accuracy, with relative error less than 5% for mean annual runoff volumes during calibration and validation periods. Modeled flow in April and May were overestimated for both calibration and validation periods. It is attributed to the irrigation for corps （such as cotton） in the catchment, which has consumed much water from stream channels. Since there is few industries in the catchment, the water quantity overestimated by the VIC-3L model could be regarded as irrigation water from surface runoff in the catchment. The impact of spatial variations of meteorological inputs, soil and vegetable properties were also estimated by using two different resolutions in the catchment, respectively. It was concluded that model parameters calibrated at the resolution of 0.5°×0.5° are suitable for the finer resolution with spatial variations of meteorological inputs, soil and vegetable properties, but may be not the optimization parameters.