Method Study of Constructing Digital Water shed for Large- scale Distr ibuted Hydrological Model
大尺度分布式水文模型数字流域 提取方法研究

Large-scale distributed hydrological model plays an important role in the coupling atmospheric and hydrological models research at present.In this paper,ZB algorithm is proposed to obtain base on 1 km grid scale DEM data,because it can maintain data information about drainage basin boundaries and river networks very well at coarser resolutions.We apply ZB algorithm and grid-averaged algorithm at 5km,10km,15km,and 20km scales in the upper Yellow river(above Tangnaihai station,drainage area 121,972 km2).Elevation,slope,wetness index,drainage density,length of main channel,watershed area and other parameters are extracted and compared with the parameters that are obtained based on 1 km DEM.Results show that DEM data obtained by ZB algorithm can hold stream network continuity and real watershed boundaries very well,and meanwhile it can decrease the amount of other geographical information falling off,compared to other algorithms.The method can supply satisfied digital watersheds for constructing large-scale distributed hydrological model.