基于SWAT模型的岷江上游流域水文模拟与干旱评估

以地势复杂、海拔高差悬殊的岷江上游流域为研究区域,选取2013~2017年水文、气象观测、土地利用、土壤类型及DEM等数据,驱动SWAT（Soil and Water Assessment Tool）分布式水文模型,在参数敏感性分析的基础上对模型进行校正和验证,模拟岷江上游流域日径流量变化过程,并采用基于SWAT计算的CI综合气象干旱指数,分析岷江上游流域典型年份干旱灾害的时空演变特征。结果表明：（1）SWAT模型在岷江上游流域具有较好的适用性,校正期及验证期R²和E_NS值均在0.70以上;（2）SWAT模型能较好地模拟岷江上游流域的水文变化过程,实测与模拟的逐日径流量变化趋势大体一致,尤其是6、7月主汛期时段的模拟效果最好;（3）基于SWAT计算的CI综合气象干旱指数较为客观地反映了岷江上游流域干旱的时空演变特征,有助于实现干旱灾害的监测和评估。

Hydrologic Simulation and Drought Evaluation in Upper Reaches of Minjiang River Based on SWAT Model

The Land use/cover data, soil data, topography data, meteorological data and hydrological data from 2013 to 2017 were used to establish a distributed hydrological model-SWAT (Soil and Water Assessment Tool) in the upper reaches of the Minjiang River. Based on the sensitivity analysis of model parameters, the SWAT model was calibrated and validated to get accurately simulated value of daily runoff which was accessible for hydrological process simulation in upper reaches of Minjiang River. Moreover, with the help of SWAT model, the CI index regarded as an effective index of agricultural drought was calculated to analyze characteristics of the spatiotemporal distribution and variation of drought hazard in this area. Results showed that: (1) SWAT model achieved a good return of applicability analysis in upper reaches of Minjiang River, the Nash-Sutcliffe efficiency coefficient E_NS and the coefficient of determination R2were respectively above 0.7 in both validation and calibration period. (2) SWAT model described the hydrological process well in this area, and the simulated value of daily runoff showed a similar trend of change as the observed value, especially in the main flood season (from June to July). (3) The CI index reflected the spatiotemporal distribution and variation of drought hazard objectively in typical drought year. It indicated that the drought evaluation based on SWAT model was a helpful tool for drought monitoring and early warning at watershed scales.