黄河口海岸线演变时空特征及其与黄河来水来沙关系

黄河是世界上含沙量最高的河流 ,每年向河口三角洲及附近海域输送数亿吨泥沙 ,使得黄河口地区成为世界上海岸线变迁最快的地区。本文以 1976年黄河改道清水沟流路以来 2 0景多时相遥感影像为主要数据源 ,经过几何精校正与配准 ,形成相对完整时间序列的遥感影像集。在此基础上 ,对影像进行监督分类处理后自动提取海岸线 ,通过GIS叠加分析 ,剖析了现行黄河河口地区海岸线演变的时空动态特征。最后 ,结合利津水文站水文统计资料 ,探讨了黄河口海岸线演变与黄河来水来沙条件之间的关系 ,并就黄河口未来水沙条件初步预测了其演变趋势

Analysis on spatio-temporal feature of coastline change in the Yellow River Estuary and its relation with runoff and sand-transportation

It is well known that the Yellow River is the river with the highest sediment contents of all rivers in the world Several hundred million tons of sediments are transported to the coast and to the sea nearby annually, so the Yellow River Estuary area has witnessed the fastest coastline changes in the world This paper describes the spatio temporal features of the coastline dynamics in the estuary area using remote sensing images since the course of the Yellow River was changed to Qingshuigou channel artificially in 1976 Trying to anatomize the spatio temporal features of coastline evolution, 20 sheets of Landsat images were used as the data source The multi temporal satellite images were rectificated precisely and registered each other, and all the images have the same coordinate system After supervised classification the coastlines were extracted automatically from remote sensing images The result shows that a new land of 330 km 2 was formed during 1976 to 2000 by GIS overlay analysis Finally, combined with the hydrologic data from Lijin station, the relation between coastline change and the runoff and sand transportation was analyzed, and the evolution trend was forecasted The results are as follows: (1) The method in the paper is viable to monitor the coastline change (2) Generally, the land forming speed is faster at the initial stage after course change, and the range of the spit shows a strong linear positive correlation with the net epirogenetic area But the coastline begins to erode after the sediment source is broken off absolutely (3) The evolution process during 1976 to 2000 is divided into four stages based on the spatio temporal features of the coastline (4)There is a consanguineous correlation between the ranges of the spit and the runoff and sand transportation, and the speed of the coastline change will become slow in the future according to the present condition of the runoff and sand transportation