中文摘要：

可变下渗能力模型VIC是基于单元网格的分布式水文模型,易于与气候模式进行耦合,从而揭示气候变化对水循环的复杂影响,为分析气候变化情景下流域洪水的响应特征提供技术支撑。作为研究工作的第一步,构建了基于5km×5km网格分辨率的西苕溪流域VIC径流模拟模型。利用流域出口横塘村水文观测站1990～2000年日流量观测数据并结合西苕溪流域的汇流特点,采用Dag Lohmann汇流模型进行参数率定和验证。模拟结果表明：VIC模型对西苕溪流域日、年径流量的模拟值与观测值吻合良好,率定期和验证期的多年平均年径流相对误差Er分别为0.77%和3.43%,模拟日或月流量的确定性系数和Nash-Suttcliffe系数都大于0.75,特别是对洪水年汛期流量过程的模拟,确定性系数均大于0.80,模型对洪水的模拟可信性较高。

英文摘要：

VIC model is a distributed hydrological model based on grid,which is flexible to be coupled with GCMs to evaluate the effect of climate change on hydrological process.As the first part of this study,VIC model for the Xitiaoxi catchment with a spatial resolution of 5 km×5 km for each grid was developed.According to the flow routing characteristics in the Xitiaoxi catchment,a routing scheme developed by Dag Lohman with the unit hydrograph method for overland flow and the linear Saint-Venant method for channel flow was used to route the simulated daily runoff to the outlet of Xitiaoxi catchment to do model calibration and validation based on observed data（1990~2000） from Hengtangcun gauging station.The results show that VIC model was adaptable for the study area,and the relative errors of the annual average runoff in Hengtangcun hydrologic station were 0.77% and 3.43% respectively.The coefficient of determination and Nash-Suttcliffe efficiency coefficient were both greater than 0.75.Especially for the simulation of discharge during flood seasons,deterministic coefficient were all greater than 0.80.It is feasible to use VIC model to analyze the response of flood on future climate change,and the related results will be presented in the following partner paper.