Research On The Division Method Of Distributed Hydrological Model Calculation Unit Considering Topographic Features And Hydrological Structure

As one of the important basic tasks of constructing distributed hydrological model,the division of computing unit determines the structure of distributed hydrological model and plays a crucial role in the application of the model and the accuracy of simulation.Since the current calculation unit division method is not enough to reflect the widely varying geomorphological features and hydrological structure of different basins,it is necessary to explore the basin calculation unit division method suitable for different geomorphological characteristics and hydrological structure,and to promote the distributed hydrological model.and applications are important.Based on the existing theories of computing unit division methods of distributed hydrological models,this paper proposes three computing unit division methods for three types of special watersheds and applies them to three typical watersheds.At the same time,the confluence module of the distributed hydrological model WEP-L is improved,and the calculation unit division result is applied to the construction of the distributed hydrological model.The main research contents are as follows:(1)A computing unit division method considering the plain is proposed,and based on the existing computing unit coding principle,a new method for determining the topological relationship between the upstream and downstream of the computing unit that can meet the coding requirements of the hydrological model for the computing unit is proposed,and it is applied.Construction of a distributed hydrological model in the Weihe River Basin.The newly proposed calculation unit division method realizes the mixed division of sub-basin units for mountainous areas and grid units for plain areas,which can better reflect the different surface and groundwater flow characteristics in mountainous areas and plain areas.(2)A computing unit division method considering lakes is proposed,and based on the existing computing unit coding principles,a new method for determining the topological relationship between the upstream and downstream of computing units that can meet the coding requirements of the hydrological model for computing units is proposed and applied.A distributed hydrological model was constructed in the source region of the Yellow River(the region above Tangnaihai).The newly proposed calculation unit division method takes into account the relative independence of lakes in the watershed,and can easily calculate the various sub-items of the output lakes in the water circulation process of the watershed.(3)A computing unit division method for the closed inner flow area is proposed.Based on the existing calculation unit division method,an improved calculation unit division method for closed internal flow area is proposed,and it is applied to the construction of a distributed hydrological model in the Qaidam Basin.The newly proposed calculation unit division method can better divide the calculation unit of the closed inner flow area,and the extracted watershed boundary has a high degree of agreement with the actual one..