黄河三角洲废弃叶瓣海岸侵蚀与岸线演化

利用Landsat TM卫星遥感图像,对黄河1964~1976年间形成的三角洲叶瓣自1976年废弃以后的岸线进行了识别,选取了四个典型剖面,绘制了它们的岸线蚀退或淤进平均速率曲线。结果显示,不同剖面处天然岸线的蚀退或淤进速率很有规律。根据曲线特征将其分为蚀退期,转换过渡期和周期性波动期。现废弃叶瓣已进入周期性波动期。由于受大坝影响,不同位置岸线波动周期不同,两大坝之间约为4年,大坝西侧约为5年,岸线变化准平衡线位于1996年的海岸线附近。岸线变化速率波动幅值将随着时间的延长而减小。

The Coast Erosion and Evolution of the Abandoned Lobe of the Yellow River Delta

The statistical results of predicting coast change of the Yellow River abandoned delta lobe formed from 1964 to 1976 are put forward using Landsat TM imagery. The velocity of coast erosion or accumulation obtained from four different classic profiles selected were calculated and its change curves with time were plotted. The curves suggested that the regularity of the evolution of coastline after the delta lobe was abandoned is very obvious. It can be divided into three different phases: erosion phase, transition phase and cyclical change phase. The coastline change cycle located in between the two dams is 4 years and that located to west of the dams is 5 years. The analysis shows that the quasi-equilibrium line of coast is located near the coastline of 1996. The coast in the dam areas will recede 1.79 km to reach to equilibrium line. Therefore, effective measures must be taken to protect the dam. But the magnitude of evolution velocity will decrease with the elapse of time and at the same time it proved that the evolution of silty coast actually was a cyclical change process too.