| 摘要: |
| 经济社会的发展导致河流利用程度越来越高、负面效应累积严重,分析多因素下的河流演变规律,能为其合理开发利用、科学保护与管理提供基础支撑。以长江南京河段为例,收集1984-2020年间Landsat卫星遥感影像,利用归一化差分水体指数法提取特定水位下的河段水边线,利用形态学方法提取河床边界和洲滩,利用本征正交分解法分析河床和洲滩平面演变特征。结果表明：近40年以来,南京河段河床边界受人类活动影响向内收缩(对应水域面积减幅6%),并以长江村附近程度最为剧烈；河段五大洲滩中,八卦洲、梅子洲及新济洲的形态变化较小,新生洲洲头消退和洲尾淤长程度相近,而新潜洲自洲头向下游逐渐淤长。河床边界与洲滩时间序列的一阶模态(含能比例>83%)反映出时均形态,其他高阶模态反映出局部冲淤消长规律,模态分析法可以很好的反映出不同时段河床与洲滩的消长特征。 |
| 关键词: 长江南京河段 河床边界 洲滩 Landsat 归一化差分水体指数 形态学方法 本征正交分解 |
| DOI： |
| 分类号:TV142 |
| 基金项目:国家重点研发计划(2022YFC3204504)；国家自然科学基金面上项目(52179072) |
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| Morphological evolution of river and sandbars based on satellite remote sensing image: A case study of the Nanjing reach of the Yangtze River |
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YANG zhi1, DONG kunming2, WANG shan3, CHEN Huai4
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1.Anhui Modern Traffic Design and Research Institute Co,LTD;2.Water Development Planning and Design Co,Ltd;3.Jiangning Street Water Management Service Station of Jiangning District;4.水利部交通运输部国家能源局南京水利科学研究院
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| Abstract: |
| With the development degree of river getting higher and higher, the negative accumulating effects are becoming serious. Evolution analysis results can provide basic support help for scientific utilization, protection and management of rivers. Taking the Nanjing reach of the Yangtze River as a typical study case, the monthly Landsat remote sensing images from 1984 to 2020 were collected. The normalized difference water index method, the morphological method, and the proper orthogonal decomposition method were used to extract riverbed boundary and sands and their plane evolution characteristics. Results show that in the past 40 years, the riverbed boundary of the Nanjing reach of the Yangtze River was shrunk by 6% due to human activities, and the most violently evolutionary place was near the Yangtze River Village. For the five major sandbars in the Nanjing reach, Bagua Sandbar, Meizi Sandbar and Xinji Sandbar have little change; the eroding degree of the head of the Xinsheng Sandbar is similar to the deposition degree of its tail; while the Xinqian Sandbar is gradually deposited from the upstream to the downstream. The first-order modes (energy content > 83%) of riverbed boundary and sandbar series reflect the time averaged morphology, while other high-order modes reflect the erosion and deposition of local areas. Modal analysis method can well extract the evolution characteristics in different periods. |
| Key words: Nanjing reach of the Yangtze River shoreline sandbar Landsat image normalized difference water index morphological method proper orthogonal decomposition |
