摘要
沙洲是冲积河道泥沙长期淤积的产物,河道既为沙洲提供发育空间又约束沙洲自由发展。以沙洲的卫星图片为依据,选取长江、汉江、西江、湘江、黑龙江、密西西比河及额尔齐斯河的653个单个沙洲及所在河道作为统计对象,初步划分了3种典型沙洲形态:椭圆形、竹叶形和镰刀形,并统计分析了3种沙洲自身形态及其与河道的关系。研究表明,椭圆形沙洲分布最为广泛数量最多,其次是竹叶形和镰刀形沙洲。竹叶形沙洲的周长和面积一般较大,镰刀形居中,椭圆形较小。沙洲面积与周长,沙洲面积与河宽都呈幂函数关系。沙洲洲面中点的宽度与河宽相关性好,相关系数依次是,镰刀形>竹叶形>椭圆形;沙洲周长与河宽相关性较好,相关系数依次是镰刀形>竹叶形>椭圆形。沙洲将河道分成主汊和支汊,3种典型沙洲的河道分汊比均保持在0.09至0.97之间。
Sand bars are the result of long-term sediment deposition in alluvial rivers.A river channel not only provides a development space for a sand bar but also restricts its free development.Three types of sand bars,including ellipse,bamboo leaf and sickle sand bars are classified from satellite images,in which 653 sand bars are in Yangtze,Hanjiang,Xijiang,Xiangjiang,Amur,Mississippi and Irtysh Rivers.The relationship between the three typical sand bars and river channels is analyzed.The ellipse sand bars in seven alluvial rivers are the most widely distributed and their quantity is larger than bamboo leaf sand bar and sickle sand bars.The area and perimeter of bamboo leaf sand bars are generally the largest,the sickle sand bars are in the middle and the ellipse sand bars are the smallest.Relationship between sand bars area and perimeter and relationship between sand bar area and channel width follow the law of power function.The relationship between the sand bar average width and the channel width has good linear correlation;the correlation coefficients diminish from the sickle,then the bamboo leaf to the ellipse.Simultaneously,the relationship between the sand bar perimeter and the channel width has linear correlation;the correlation coefficients diminish from the sickle,then bamboo leaf,to the ellipse.The river channel is divided into a primary channel and a secondary channel by a sand bar.The branching ratio of river channel for the three typical sand bars is located in the range from 0.09 to 0.97.
出处
《泥沙研究》
CSCD
北大核心
2012年第1期68-73,共6页
Journal of Sediment Research
基金
清华大学自主科研计划课题(2009THZ02234)"三江源河流生态动力学综合研究"
关键词
冲积河道
沙洲
沙洲形态
河宽
分汊比
alluvial river channel
sand bar
sand bar morphology
river width
branching ratio
