Distributed NAM Hydrological Model Research And System Implementation

In recent years,on the one hand,the popularization of highly efficient and convenient technologies such as computers,geographical information collection(especially satellite remote sensing and radar monitoring),and the rise of interdisciplinary thinking have enabled the realization of a distributed hydrological model that can integrate a large number of watershed attributes.On the other hand,changes in the underlying surface and people's requirements for detailed simulation of hydrological processes have also made the study of distributed hydrological models an inevitable trend,and it has gradually become one of the in dustry research hotspots.At the present stage,some scholars have successively combined remote sensing and computer technology to convert the lumped hydrological model into a distributed hydrological model,which has enabled the refinement of hydrological processes in the basin.Based on the basic principle of production and convergence of NAM model,this paper constructs a distributed NAM model based on grid and further develops a distributed NAM hydrological model system to achieve rapid modeling of distributed hydrological models in arbitrary basins.The main research contents and results are as follows:(1)In order to meet the needs of the basic data of different distributed hydrological models,a watershed property information chart was uniformly produced.Watershed basic information is an important foundation for constructing a distributed hydrological model.Due to the different model structures,the basic data required for basins in different distributed hydrological models is not the same.To avoid cumbersome data processing,the distributed hydrological model may be used in this paper.The unified extraction of watershed feature attributes is integrated into a property chart,which avoids repeated processing of data and improves the calculation efficiency of the model.(2)Considering the spatial heterogeneity of soil texture and land use types,a distributed NAM model was constructed based on the principle of production and collection of NAM models.The distributed NAM model discretizes the entire watershed grid,and the lumped NAM model is used as the runoff model in each grid.According to the integrated watershed general attribute information,the grid routing optimal calculus order is established.The widely used Muskingum model and diffusion wave model are used as a grid-by-grid surface runoff converging model.The lag calculus model is used as a subsurface flow and underground runoff confluence model and the SCE-UA algorithm is used to optimize model parameters.After the applicability of the lumped and distributed NAM models in the Hanjiang Xunhe River basin was compared and analyzed,the calculation results show that the distributed NAM model constructed has strong applicability and can simulate the spatial distribution characteristics of watershed hydrological processes.(3)To further verify the applicability of the distributed NAM model,it is compared with the distributed Xin'anjiang model.Based on the integrated watershed general attribute information,combined with the principle of distributed Xin'anjiang model production and convergence,the distributed Xin'anjiang model was quickly constructed.Compared with the distributed Xin'anjiang model in the Xunhe River Basin,the distributed NAM model has the characteristics of simple structure and few parameters,and is also more efficient in automatic optimization of model parameters.(4)Based on the B/S architecture model,Java language and Eclipse development tools are used to implement the system development of the distributed NAM model.Combining the theoretical method of the distributed NAM model and the actual needs of actual flood forecasting,the system has four functional modules: watershed general property information analysis,basic data processing,flood management,and parameter rate determination required for flood simulation.Implementation of distributed hydrological model construction in arbitrary basins;in order to ensure the maintainability and scalability of the system,the system adopts a mainstream development environment and a mature system framework,and a common interface is designed to achieve the purpose of flexible addition and configuration of hydrological models.For the relevant personnel to provide a production and scientific research system platform.