基于GIS长江口北港河段冲淤变化的可视化分析

GIS-based visualized analysis of scouring and siltation in North Channel of Changjiang Estuary

利用GIS技术，建立长江口北港1973～2003年间不同时期的水下数字高程模型，以此作为基础资料，通过叠合分析不同时期的水下地形图，得到长江口北港不同时段相对的河床冲淤分布图．分析了长江口北港30年来河道的冲淤变化和演变情况，并计算了河道泥沙冲淤量．结果表明，GIS技术是研究河床演变规律的一种行之有效的可视化方法；北港河段在1973～2003年问整体呈冲刷之势，泥沙冲刷量为1．58亿m^3，平均每年冲刷0．05亿mz^3；北港河床航道稳定性较差，受南、北港分汉口演变的影响，北港河床逐渐演变．洪水在北港河槽演变过程中起着重要的作用.

An underwater digital elevation model for the North Channel of Changjiang Estuary for different periods from 1973 to 2003 was developed by use of GIS technology, and the distribution of riverbed scouring and siltation was obtained by overlapping of underwater topographical map. The analysis of variation of scouring and siltation and evolution of the North Channel for recent 30 years and the calculation of the volume of scouring and siltation show that GIS technology is an effective method for visualized analysis of the law of riverbed evolution. It is concluded that the North Channel was characterized by scouring from 1973 to 2003, the volume of sediment scouring being 1.58× 10^8 m^3, and the mean volume of annual scouring being 0.05×10^8 m^3, and that the riverbed of the North Channel is unstable due to the change of the fork of the South anti North Channel. Besides, flood plays an important role in North Channel evolution.