冲积河流中沙洲形态统计分析

Statistical Analysis of Sand Bars Form in Alluvial Rivers

基于Google Earth卫星图像,选取长江、汉江、西江、湘江、黑龙江、密西西比河及额尔齐斯河中共计655个沙洲作为统计样本,分析了沙洲的面积与周长及最大长度与平均宽度的定量关系,探讨了沙洲形态与分汊比及沙洲平均宽度、面积、周长与河道宽度的关系。结果表明,沙洲面积与周长、河道宽度均呈幂函数关系,沙洲最大长度与平均宽度及沙洲平均宽度、周长与河道宽度均保持较强的线性相关,沙洲所处河道的分汊比一般保持在0.09～0.97之间。

Google Earth satellite images are used to analyze the characteristics of sand bars which are 655 statistical samples in Yangtze River, Xijiang River, Xiangjiang River, Heilongjiang River, Mississippi River and Irtysh River. The relationship between sand bar area and perimeter presents the law of power function, and the same law between sand bar area and channel width. Sand bar maximum length and average width, sand bar average width and channel width, sand bar perimeter and channel width keep strong linear relationship. Branched ratios of sand bars in alluvial river channels are generally located the range from 0.09 to 0.97.