南黄海辐射沙洲陆岸岸滩时空演变特征与机制遥感研究

Muddy coast is an important type of coastal zone in China. Monitoring, analyzing and revealing the temporal and spatial dynamic evolution characteristics and mechanism of muddy coast is of great significance for rational exploitation, utilization and protection of beach resources. In this proposed project, shore area of radial sand ridge in the southern yellow sea is chosen as the typical muddy coast for the mechanism study of coastal variation by means of remote sensing, GIS based spatial analysis and shallow water numerical simulation technique. Firstly, under the condition of blurring of land and water boundary, waterline retrieving method from satellite image was concerned. A new dynamic modeling and slope fitting method of beach profile were proposed. Methods of extracting and calculating the tidal channel network and simulating the sediment transport patterns in beach surface were also thoroughly studied. And then the remote sensing shoreline changes, tidal channel swing and sediment transport information were obtained. They were used for understanding of the remote sensing mechanism of beach surface sediment dynamic processes and the response of beach morphology. Finally, these knowledge were coupled for the exploration of dynamic change characteristics of muddy coast on radial sand ridge under different temporal and spatial scales. They can explain the response of coastal dynamic change under the influence of natural factors and human activities such as typhoon storm surge and the reclamation process. On this basis, the time inflection point and spatial location node for coast dynamic changes could be determined. The future trend of the variation of beach could also be predicted. This research will be helpful to reveal the real change process of coast in radial sand ridge. It can also be consulted as an effective remote sensing monitoring method and technique support for the coordination and development of the exploitation of resources and environment in muddy coast area in our country.

淤泥质海岸是我国重要的海岸带类型。利用遥感技术监测、分析和揭示岸滩的时空动态演变特征与机制，对淤泥质海岸岸滩资源的合理开发、利用与保护具有重要意义。本课题选择南黄海辐射沙洲陆岸岸滩为典型研究区，通过重点研究和改进水陆模糊条件下的瞬时水边线精确提取方法、岸滩剖面动态建模与坡度拟合方法、滩面潮沟网络提取和参数计算方法以及滩面沉积物输运格局模拟方法，获取不同时相、不同空间尺度的遥感海岸线变迁、潮沟摆动和沉积物空间输运趋势信息，以此了解岸滩形态变化对滩面沉积动力过程响应的遥感机制；在此基础上，进一步分析台风暴潮、滩涂围垦等自然因素和人类活动影响下的岸滩动态变化响应，研究辐射沙洲陆岸岸滩的时空动态演变过程与规律，确定岸滩演变的时间拐点、空间节点及其变化特征，预测岸滩未来的变化趋势。预计研究结果将有助于揭示辐射沙洲陆岸岸滩的真实变化过程，并为我国粉砂淤泥质海岸资源与环境的协调利用与发展提供研究基础。

南黄海辐射沙洲淤泥质海岸陆岸岸滩空间分布范围广，坡度平坦，滩面条件恶劣，冲淤动态变化快。本项目以多源、多时相、多分辨率卫星遥感影像为主要数据源，综合应用遥感、GIS、潮汐数值模拟技术和机器学习技术，围绕南黄海辐射沙洲陆岸岸滩的时空动态演变特征与机制开展研究，系统建立了淤泥质海岸遥感海岸线提取及岸线岸滩动态变化分析技术体系，提出了顾及滩面微地形起伏的潮间带三维地形DEM增强型遥感构建方法，发展了潮滩表层沉积物粒度参数、粒径趋势输运空间格局、潮沟系统形态特征的遥感监测方法，分析了典型人类活动对粉砂淤泥质海岸面积、坡度、沉积环境、潮沟形态等的响应及其影响机制。研究发现，近30年来，江苏省海岸线总长度不断增加，人工岸线长度增加明显，自然岸线总长度锐减。潮间带平均坡度呈不断变陡的趋势，潮间带面积和平均宽度逐年减少。滩面潮沟数量与长度由于滩涂围垦、港口建设等人类活动的影响不断减少，潮沟总体上不断退化，潮沟形态变得简单，发育状况变差，潮沟分维值呈现波动下降的趋势，潮沟复杂性降低。随着潮间带宽度、面积的减少，江苏沿海海岸带的蚀淤转换节点由20世纪80年代的射阳河口南移至目前的斗龙港附近，并有逐年南移的趋势。同时淤长型海岸也存在海岸侵蚀特征，间隔分布在斗龙港至梁垛河口的辐射沙洲北翼海域。围绕课题研究内容，课题组成员发表基金标注论文（其中SCI论文5篇、中文核心期刊论文9篇），撰写海岸线时空变化遥感监测技术、方法与应用专著2部，申请相关专利2项，参加国内外学术会议交流10余人次，培养硕士毕业研究生5人，获得江苏省科学技术奖三等奖、国家测绘科技进步奖二等奖、江苏省测绘地理信息科技进步奖二等奖等科技奖励4项，项目研究工作达到了预期目标。研究成果可为辐射沙洲陆岸岸滩资源的合理开发、利用与保护提供了科学依据，也可为我国强潮粉砂淤泥质海岸的资源与环境协调利用与发展提供方法基础与技术支撑。