【作者】 吴稳；

【导师】 周云轩；

【作者基本信息】 华东师范大学 ， 自然地理学， 2010， 硕士

【摘要】 长期的河口海洋调查积累了大量的水文环境数据,这些以水深、盐度、浊度、潮流等参数为核心的水文环境数据因来源、结构、维度的差异,难以融合进行综合表达,且基于一维或二维的表达方式,信息量少,直观性差,难以充分表达出水文环境和水下地形的真实特征及其他们之间相互作用、相互影响的密切联系。本文将可视化技术、GIS技术、三维建模技术相结合,构建了长江口水文环境场景,为各类水文环境综合分析和地形演变分析等提供一个良好的平台。主要研究内容如下：(1)真实感水下地形模型的构建。运用分形布朗运动(fBm)模型得到水下地形的分形特征参数,结合随机中点位移内插算法,通过Matlab编程实现了三维水下地形的模拟。模拟结果显示fBm方法较其它方法得到的结果可视化效果好,模拟的地形具有丰富的表面细节和粗糙质感,反映了地形的复杂性和不规则性,具有很好的视觉效果,同时也保障了较高的精度。另外使用可视化软件Fledermaus对水下地形进行渲染,制定了适合水下地形模型的配色方案,并以遥感影像作为纹理映射到地形中,提高地形的逼真程度。同时对地形进行阴影、光照、透明度等设置,提高地形的可视化效果。(2)长江口水文环境专题模型库的构建与场景关联可视化表达。结合使用GIS软件、Matlab编程、3ds Max建模软件和可视化软件分别对长江口泥沙浓度、盐度、底质类型、特征地物进行建模。可视化地反映了泥沙浓度的空间分布、盐度的垂向分布、长江口底质沉积物类型和长江口特征地物的分布状况。并完成了将各模型与水下地形相关联,塑造了一个逼真、交互的河口水文环境场景。(3)长江口典型沙洲和边滩的冲淤演变分析。研究区域包括顾园沙、崇明东滩、横沙浅滩、九段沙和南汇边滩,涵盖了长江口口门大部分面积。在Fledermaus中根据各区域的地形模型,构建年份间的地形冲淤模型(1990-2004),可视化冲淤变化情况,计算冲淤量和冲淤速率等相关参数,结合等深线水平变化情况,分析长江口典型地形的演变规律。更多还原

【Abstract】 A variety and numerous of spatial-temporal hydrological environmental data such as water depth, salinity, turbidity, tidal current have been obtained and measured in field over past years at Yangtze estuarine area. For the nature and complex of diversity source, instruction, type, dimension on in-stiu data, it is absent and insufficient to visualize the geographic distribution, interaction and relation among these data at surface and under water level with one or two dimension expressions way. In this paper, we construct hydrological scenario and three dimensions visualize platform for displaying, expressing, analyzing and simulating past, current and future hydrological and environmental data, in conjunction with GIS, visualize technology and 3D modeling. The content of this paper including:(1) The construction of underwater relief model. Fractional Brownian motion (fBm) model was used to compute fractal parameters of underwater terrain and the interpolation algorithm combining with the random midpoint displacement method was implemented to construct 3D underwater relief by Matlab toolkit package. The result show that:it has preferable detail and precision on terrain’s complexity and irregularity using fBm model. With Fledermaus visualization software, the real show of underwater relief was realize with the texture layer of remote sensing image by adjusting color scheme and Fledermaus parameters, such as terrain shadow, view point, luminance and transparency.(2) The establishment of hydrological environmental models and Yangtze Estuary environmental scenario visualization. With GIS, Matlab,3ds Max and Fledermaus software, we integrally development a real and interactive Yangtze Estuary environmental scenario simulation system to construct sediment concentration model, salinity model, sediment type model and typical features model and to display spatial distribution of sediment, salinity vertically distribution, the type sediments and surface features at the mouth of Yangtze River.(3) The study of accretion and erosion at typical shoals and tidal area at the mouth of Yangtze area. We select Guyuansha shoal, Chongming Dongtan, Hengsha shoal, Jiuduansha and Nanhui bank as case study area. With the accretion and erosion model developed by Fledermaus package, topographic evolution and isobaths distribution at Yangtze Estuary was analyzed and deposition rates were calculated during the period from 1990 to 2004.更多还原