降水空间不均匀性对径流过程模拟的影响

应用数字高程流域水系模型，通过子流域和网格2种空间离散方式，采用传统的子流域法、雨量插值子流域法、逐个网格法3种雨量数据输入处理方法，分别作日流量模拟与洪水过程模拟，模拟过程与实测水文过程相比较表明：日模中3种雨量处理方法计算精度相当，次模中逐个网格法优于传统子流域法和雨量插值子流域法；降雨空间分布不均匀性考虑得越充分，水文过程模拟精度越高。

Effect of Spatial Precipitation Heterogeneity on Runoff Process

The Digital Elevation Drainage Network Model is used for the determination of raster flow vectors, the delineation of subcatchments, and the extraction of river network from the digital elevation model data. On the basis of two ways of spatial discretization: grid and subcatchment, three methods are applied to processing precipitation data as the input of hydrological model, so as to analyze the effect of spatial precipitation heterogeneity on runoff process. The first is the conventional subcatchment method by taking directly rain -gauge data measured within the subcatchment as the input of the subcatchment. The second is modified subcatchment method by interpolating rain- gauge data to each grid, then averaging rain values over all grids within a subcatchment as the input of the subcatchment. The third is one-grid by one-grid method by taking rain value interpolated to a grid element as the input of that element. Those three methods are utilized for the simulation of daily runoff and flood discharge, respectively. A case study in the Baohe catchment shows that three methods make little difference in the computation of daily discharge, while the one-grid by one-grid method performs better than the conventional subcatchment and the modified subcatchment methods in flood discharge modeling in terms of model efficiency coefficient. The conclusion can be drawn that the more sufficiently the spatial rain heterogeneity is taken into consideration, the higher the accuracy of flood modeling is.