利用GIS和RS技术分析青藏高原风火山小流域地形地貌特征

以30×30m DEM为基础,在GIS技术辅助下,以青藏高原风火山小流域为例,设计了水文响应单元划分的实现方案和算法,并结合不规则网格的有限体积法,进行流域水文模拟方式的探讨。从DEM中提取子流域,利用遥感图像进行土壤覆被类型划分,使得生成的每个水文单元有单一的土壤覆被类型,并根据所得类型图,进行流域积水面积阈值的求取;结合有限体积法不规则网格技术,对流域网格划分进行讨论,确定用于微分方程求解的编码方式。结果表明:结合RS和GIS能较准确地划分流域土地利用类型,求取河网集水面积阈值,划分流域网格单元和存储结点数据,实现了分布式流域建模的空间离散化,用于冻土草地区模型数值模拟具有方便、可行性。

Analysis of topographic feature of a small watershed in Fenghuoshan mountain basin with GIS and RS technology

Based on the 30×30m DEM and GIS, taking an example of the Fenghuoshan Basin in Qinghai-Xizang Plateau, the paper discusses watershed hydrological modeling and designs the scenario and algorithm of the hydrological response unit(HRU)division with finite volume method of irregular grid. Sub-basins are generated from DEM data, and types of soil cover can be devided by remote sensing images. Every hydrological unit has a uniform type soil cover, threshold value of catchment area is calculated based on the chart to get the threshold of watershed area catchment area. Combined with the irregular grid of finite volume method, the paper discusses the watershed grid division, and then defines decoding method of the differential equation. The results show that combining RS with GIS can accuratly divise the land use type of watershed and get the threshold of watershed catchment area. Spatial discretization of distributed hydrological model is realized by divising wathershed grid unit and storing grid data. It's practicable and workable to apply this method to numerical simulation of permafrost meadow area.