中文摘要：

水文模型是模拟水循环过程重要手段,依靠单个模型进行模拟往往存在很大的不确定性,使通过多模型进行组合模拟成为必然趋势.选取3个集总式水文模型应用贝叶斯模型平均（BMA）进行流域月径流量的多模型模拟,采用期望最大化算法推求BMA分布参数以得到BMA均值模拟序列和90％不确定性区间.以武烈河实测数据为例进行分析,结果表明：BMA方法既能通过均值模拟提供更高精度的模拟效果,还可通过不确定性置信区间定量评价模型结构不确定性,为径流模拟提供丰富信息.

英文摘要：

Hydrologic model is a significant tool to simulate the water cycle,while there is great uncertainty depending on single model simulation which makes ensemble hydrologic model simulation become inevitable trend.Three lumped hydrological models were selected to conduct watershed monthly runoff ensemble simulation,and the expectation maximum algorithm was used to estimate the parameters of the BMA in order to obtain BMA mean simulation and 90% uncertainty interval.The result using the observed data of the Wuliehe watershed indicates that the BMA method can not only provide simulation with higher precision through mean simulation,but also provide quantitative evaluation of the model structure through confidence interval which could offer rich information of the runoff simulation.