基于DEM的流域河网信息自动提取算法
A DEM Based Drainage Networks Extraction Module Seamlessly Integrated in a Distributed Hydrological Model
中文摘要：
分布式陆面水文过程的模拟，除了经典水文模型所必需的流域气象、水文信息外，还需要研究流域的详细地形、水系信息，方可实现流域内产流和汇流的时空演算。以往通常需要借助商业软件在研究区DEM上提取这些水系信息，不仅耗时、操作不便，还使得模型结构松散。在自主研发的一种分布式水文模型的基础上，开发了一套用于提取水系信息的模块，并与该水文模型以同一种语言紧密耦合，程序完全采用面向对象的方式自主编写，大部分数据交换均在内存中直接进行，而无需占用磁盘空间，运行速度快，易于今后不断完善和扩展。详细介绍了模块中填洼与平坦区域处理、流向与累积流向矩阵生成、Strahler河道等级的确定、子流域生成、汇流次序和流程长度信息的生成等多种流域河网信息提取的具体算法及程序实现。本模型系统完全采用自主方式开发，克服了以往使用商业软件提取河网信息时的限制，使得分布式水文模式的流域模拟及分析功能更强大齐全和今后进一步完善和扩展。
中文关键词：
分布式水文模型，数字高程模型，水系提取，耦合模块
KeyWords：
distributed hydrological models, digital elevation models, drainage networks extraction, coupled module
Abstract：
For simulation of the hydrology in a watershed by distributed hydrological models, besides the meteorological and hydrological data needed, the detailed information such as topography and watershed networks is also necessary. Traditionally, the drainage networks were derived from digital elevation models (DEM) using commercial software, which is time consuming and inconvenient for operation in hydrological modeling. Based on a distributed hydrological model (DHM) developed by us, an automatic watershed information extraction module was developed which is able to be integrated into the DHM seamlessly using the same computer language of C#. Therefore, most of the data transferring can be finished in memory with no occupation on hard disks, so it is highly efficient when running. The algorithms for the watershed information extraction were introduced, such as the algorithms of removing of depression and flatten areas, generation of flow direction and accumulating flow direction, obtaining Strahler river order, dividing of sub watershed and calculation the sequence of flow order and water-drainage length. This system overcomes the limitations of using commercial software for extracting watershed information, and also favors the modeling system for convenience of modifying and extending the model easily in the future.