黄河水文特征对河口海岸变化的影响

论文选取海陆变化频繁的黄河口作为研究区,在3S技术支持下采用平均高潮线法对1976-2002年18个年份的遥感影像进行了海岸线信息提取。对研究区海岸变化的叠加分析表明:1976-2002年间黄河口海岸的演变过程分为直线增长、波动增长和波动减少3个阶段。同时,黄河口水文特征的变化规律及其对岸线变化影响的分析揭示了黄河水沙状况与河口海岸线的年际变化呈线性回归关系,指出了输沙量为河口海岸变化的主要驱动力,而径流量和含沙量是通过影响输沙量而间接影响河口海岸线变化,确定了输沙量3.517×108t/a为河口海陆变迁的临界值。

The Impact of Hydrological Characteristics of the Yellow River Coastline Changes in the Yellow River Delta

The Yellow River delta as a frequently changing area has been studied by using 3S techniques for us to best understand coastline dynamics of the Yellow River estuary.According to the trait of near-infrared wave which has the lowest reflecting ratio in water,the yearly coastline dynamics had been extracted by remote sensing technique during 1976 to 2002.Consequently,the overlay analysis of annual change of coastlines,supported by GIS technique,showed that the coastline stretching distance,the coastline length,and the renewed land area had fluctuated increasing trends in the research period.The changing trends could be divided into three stages obviously in more detailed temporal scales,the first was linear increase stage from 1976 to 1985,the second was fluctuating stage from 1986 to 1996,and the third was decreasing stage during 1997.Due to observation data of the Lijin Hydrological Station which is located in the Yellow River estuary,dynamics of the sediment carrying capacity of the Yellow River had been studied in the same temporal scale.There were significant yearly changing trends during research period,the carrying capacity of the 15 years changed more than 15kg/m3 during this period of time,and the maximum yearly changing rate of the carrying capacity reached 33.04kg/m3 between 1987 and 1988.In the general,the changing trend of the carry capacity of the Yellow River fluctuatedly decreased in the research period.Correlation analysis indicated that relationship between the hydrological characteristics of the Yellow River and the renewed-land amplification was most significant(significant check is more than 0.01 level.),the relation could be expressed as linear regression model.Findings also illustrated that there was a equilibrium point while runoff reached 135.32×108m3,the amount of sediment discharged was 3.517×108t,and the carrying capacity was 19.64kg/m3,all relating to the hydrological characteristics of the Yellow River.