中文摘要：

为了在洪水过程计算中定量利用面域遥感数据,拓展遥感数据及洪水计算交叉应用空间,基于水平集方法提出了采用二维水力学模型直接同化淹没范围数据的变分同化方法.通过引入水平集函数描述洪水运动界面,将浅水方程的水深变量和符号距离相结合,克服了洪水淹没范围直接同化中代价函数构造的难题.实验室小尺度的溃堤洪水过程和实际大尺度的蒙洼分蓄洪过程的合成观测数据同化数值试验表明,（1）提出的方法可将淹没范围数据所蕴含的水动力信息自动融入模型,识别分布式的糙率参数,改善洪水动力过程的分析与预测;（2）淹没范围数据包含丰富的水力空间信息,即使同化有限帧的淹没范围也可帮助改善洪水过程的模拟精度.

英文摘要：

To fully mine the potential of spatial information from remote sensing data and apply these data to the analysis and prediction of flood routing processes,a variational data assimilation model is proposed based on the level set method.The level set function is introduced to describe the flood front.Combining the variables of water level in the flood model and signed distance in the level set equation,the difficulty of constructing cost function for the assimilation of flood extent is then overcome.The proposed method implement the direct assimilation of the flood extent data into a two-dimensional flood dynamic model.The model was verified by both cases with different scales.One is the laboratory-scale dyke breach;And another one is the real scale of flood diversion to a flood detention area.Results show that：（1） the proposed method can efficiently fuse the hydraulic information hiding in the flood extent data,identify the distributed Manning roughness coeficients and then improve the analysis and prediction of flood routing.（2） Flood extent data include the rich spatial hydraulic information.Their assimilation can help to improve the accuracy of flood simulation.