A Unified Representation Of Spatial Discretization Schemes In A Hydrological Integrated Modeling System And Its Implementation

There are many well-built and widely-used hydrological models.However,no one of them are well-performed to all circumstances without any changes,because those models were developed based on different ideas and they varies in basic assumptions,conceptualizations and scope of applications.Therefore,whenever confronting a specific problem,it is necessary to establish suitable hydrological models according to the research objectives by modifying or integrating different models.The integrated modeling environment(IME)provides an efficient approach for model integration.However,there are a variety of spatial discretization methods for hydrological models,and the relationship between spatial discrete elements is complex,so it is one of the key problems for IME to integrate models based different discrete schemes and ensure the accurate interaction of spatial discrete unit.Aiming to eliminate the barriers created by different discrete schemes in the process of model integration,this dissertation took a research on the representation and realization of spatial discretization method of hydrological models in IME.The content of this research includes:(1)Analysis of computational dependence between discrete unitsOn the basis of summing up the spatial discrete schemes of hydrological models,the factors influencing the computational dependence of spatial discrete units were analyzed in terms of topographic factors and numerical solution methods.The computational dependencies among discrete units were classified into three types:independent,unidirectional and simultaneous.(2)Analysis of discrete schemes' spatial matching in hydrological modeling processFrom the perspective of the types,scales and dimensions of spatial discrete schemes,spatial matching scenarios in hydrological integrated modeling were summarized into three categories and the common spatial matching methods of each scenario and their characteristics were summarized.(3)IME-oriented unified representation of spatial discretization schemesA conceptual model for the unified representation of spatial discretization schemes is presented.Based on the idea of Node-Link,a unified representation scheme for spatial discretization of hydrological models for integrated modeling environment was proposed.The scheme consists of spatial discretization and spatial matching.The former describes the computational dependencies between discrete units and the latter describes the data conversion methods between different discrete schemes.(4)Prototype system design and example verificationThe prototype system was built on the previous work of the research group.Class libraries were designed and implemented in view of some key problems such as optimal calculation order of discrete units,module interaction and so on.Taking the GSFLOW model and Sagehen basin as an example,the proposed unified representation scheme and the prototype system were verified.The results show that the proposed unified representation scheme had a better expansibility and can better represent the characteristics of different spatial discretization methods and their interactions.The prototype system had high availability and can effectively deal with the integration of hydrological models with different spatial discretization methods.