【作者】 李真；

【导师】 李满春； 刘永学；

【作者基本信息】 南京大学 ， 地图学与地理信息系统， 2012， 硕士

【摘要】 地貌形态随时间的变化过程,是地理学历来极为关注的内容之一。尽管近30年来不同尺度的潮滩冲淤变化分析已取得很大成功,但至今冲淤季节性变化分析理论仍不够成熟,在机理分析、数据获取、分析方法等方面还有待拓展；从遥感和GIS的角度来看,现有的遥感和GIS软件也缺乏时空过程分析和动态模拟能力。江苏苏北辐射沙脊群沉积地貌体系较为特殊,它以形态特殊、地形复杂多变而著称,是潮流脊研究的典型区域,本研究在GIS、RS、空间统计等技术方法的支持下,探讨江苏辐射沙洲冲淤态势变化分析方法,对其冲淤季节性变化进行研究,符合江苏沿海开发战略要求,对世界其它地区的潮流脊及我国沿海潮流沙脊演化研究有着较强的借鉴意义,为淤泥质潮滩剖面研究提供背景资料,而且对引导研究区有序开发利用具有重要的现实意义。研究选取江苏辐射沙脊群中面积较大的东沙沙洲为研究区,利用多时相卫星影像的水边线信息构建潮滩高程模型,以多时期潮滩高程模型为数据源,将定性描述与定量计算相结合,结合遥感与GIS方法对东沙地区的冲淤变化态势进行研究,重点对泥沙冲淤总量变化、冲淤沉积速率变化、冲淤输运率及输运方向变化进行定量计算与定性分析,并探讨影响冲淤季节性变化的因素。研究主要内容包括：(1)冲淤总量季节性变化分析。本研究以按季节构建的数字高程模型为数据源,首先将栅格数据转换成文研究件数据进行分析,等间距划定不同的等高线标准,分别计算高于各等高线的标准下的冲淤面积和冲淤体积,进而计算冲淤量,并最终分析冲淤量季节性变化规律及其影响因素。(2)冲淤速率变化分析。对求交后的各数字高程模型进行差值运算,得到表示各时间段绝对高程差的栅格数据。研究重点探讨了各高程模型“成像时间”的计算方法,从而得到冲淤速率变化结果,并最终分析冲淤速率变化规律及其影响因素。(3)冲淤输运量及输运方向季节性变化分析。首先对按季节构建的数字高程模型进行求交运算及差值运算,计算栅格图像的梯度与梯度方向,以此表示冲淤输运率及输运方向。探讨将冲淤输运率及输运方向数据以模式图的形式表示,从而清晰展现冲淤变化方向及大小,并最终分析冲淤输运率及输运方向季节性变化规律及其影响因素。研究结果主要包括：(1)秋、冬季冲淤量明显高于春、夏季。春季与秋季的冲淤量持平,夏季冲淤量最低。冲淤量季节性冲淤变化与风浪、潮差、潮流、潮沟系统以及其它等因素密切相关。(2)全区域的冲淤速率极大值点集中在研究区潮沟密集处。潮滩有向西北侧移动的趋势。(3)研究区内存在着明显的输运方向的会聚与分散现象。输运方向会聚的区域表现为淤积。反之,输运方向分散的区域表现为侵蚀。输运率在潮沟分布密集处较大。更多还原

【Abstract】 The process of landforms change over time has always been one of great attention in geography science.Though, study on erosion and deposition change of sandbank under different scales has achieved great success in the past thirty years, however, theory of erosion and deposition seasonal change is still not mature enough so far, it should be expanded at mechanism, data acquisition, and analysis methods. From the point of view of remote sensing and GIS, the exiting RS and GIS software also lacks of capability of space-time process analysis and dynamic simulation.Jiangsu radial sandbank is the most special depositional geomorphologic system among the coastal regions of China which is known by the special shape, complex and changeable terrain. It is a typical region for studying tidal current ridge. Under the support of GIS, RS, and spatial statistical, this study explores method which is to analyst erosion and deposition change of radiation sandbank, studies on erosion and deposition seasonal change, fits in with the requests of Jiangsu coastal development and strategy, has a strong reference for the research of tidal current ridge of Chinese coastal and other regions of world, provides background information for the profile study of muddy sandbank, also has important practical significance of guiding the orderly development and utilization of study area.This article selects Dongsha which has a large area in radial sandbank ridges as the study area, firstly, builds tidal flat elevation models by using waterlines picked up by multi-temporal RS images, takes multi-period tidal flat elevation model as data source, combines qualitative description and quantitative calculation, uses remote sensing and GIS methods to study the erosion and deposition variation trend of Dongsha, focus on the amount change of sediment erosion and deposition, the change of erosion and deposition rate, the change of erosion and deposition transport rate and the change of erosion and deposition transport direction, explores the factors that affect erosion and deposition seasonal changes. Study include:(1)Seasonal changes in the amount of erosion and deposition. Study takes DEM built by season as the data source, converts raster data into text files, delineates different contour lines with equal interval, separately calculates erosion and deposition area and erosion and deposition volume under different contour levels, and then calculates the amount of erosion and deposition, and finally analysts the regulations of seasonal change in the amount of erosion and deposition and its influencing factors.(2)Change of erosion and deposition rate. Take the minus operation using DEM which has been extracted, obtain raster data which represents the difference in value of DEM, focuses on the calculation of the "imaging time" of DEM, obtains the result of erosion and deposition rate, and finally analysts the change regulations of erosion and deposition rate and its influencing factors.(3)Seasonal change of erosion and deposition transport rate and direction. Firstly, the study takes the intersection operation and the minus operation using the DEM models, calculates gradient and gradient direction of the raster image which is represented the transport rate and transport direction, explores the display form of a diagram using transport rate data and transport direction data, so that clearly shows the change of erosion and deposition transport rate and transport direction, and finally analysts the regulations of seasonal change of erosion and deposition transport rate and transport direction and its influencing factors.The results of the study include:(1)The amount of erosion and deposition in autumn and winter is significantly higher than in spring and summer. The amount in spring is almost the same with it in autumn; the amount is lowest in summer. Seasonal changes in the amount of erosion and deposition are closely related with wing and waves, tidal range, tidal current, tidal creek systems and other factors.(2)The maximum point of erosion and deposition rate of the whole region is concentrated in the tidal creek densely area. Tidal flat has the trend of moving to the west north side.(3)The study area, There is the obvious convergence and dispersion phenomena of the transport direction. The region in which transport direction is convergence represents deposition. On the contrary, the region in which transport direction is dispersion represents erosion. Transport rate is large in the tidal creek densely area.更多还原