一个以DEM为基础的分布式水文模型

Distributed Hydrologic Model Based on DEM

研究了如何将从DEM中提取的河网、水流路径等流域特征应用于分布式水文模型。建立了一个以传统产流模式为基础进行产流计算、网格间沿虚拟汇流网络进行汇流的分布式水文模型,并在我国东北部分流域进行了应用。重点研究了以DEM为基础的汇流方法,用汇流时间和线性水库相结合的方法进行汇流演算。结果表明,该方法提高了大尺度水文模拟的精度。

The spatial inhomogeneity of surface and precipitation affects the hydrologic process and hydrograph of a catchment. Compared with traditional lumped models, distributed models are more convenient to simulate the effect caused by the change of surface, nature and climate to hydrologic process for their distributed structure. Now those distributed models based on digital elevation model or digital terrain model (DEM/DTM) are getting more attention. A distributed hydrologic model was set up in the article. It was based on digital elevation models. The grids corresponding to the grid of digital elevation model was the minimal unit. The generated runoff of each grid was computed with some traditional runoff generation models. The runoff routing went along the dummy river-network generated from digital elevation model. Focus of the research was to study the method of using river-network, flow path and other catchment properties abstracted from digital elevation model in distributed hydrologic models, especially in runoff routing methods. A parameter called velocity constant was used to reflect the hydraulic characteristic of channels. The concentration time of every grid represented how long the flood peak being later than the rainstorm causing this flood. At the same time a linear reservoir was used to describe the flattening-out of flood procedure during the transfer.