南海西北部英罗湾红树林保护区光滩近期冲淤变化分析     

祁雅莉  付东洋  刘大召  刘贝 《海洋科学》2019,43(6):6-14

红树林岸外光滩高程变化是红树林可持续性发展的重要环境因素。本文以南海西北部英罗湾为研究区,利用多时相多源遥感影像提取水边线,并结合迭代的FVCOM水动力模型模拟方法,建立了2008年和2015年两个时期红树林岸外光滩数字高程模型(Digital Elevation Model, DEM)。利用两个时期的反演结果进行空间叠置分析,结果表明:2008年至2015年,湾顶光滩大部分呈现稳定-淤积状态;位于海湾中部至口门的光滩,从上部到下部整体呈现从淤积-稳定-侵蚀的趋势,其中光滩中部局部出现沟壑状侵蚀,与大型潮沟的发育和摆动有关;而光滩上部冲淤的空间差异性,主要由于红树林林区扩张形态以及人类活动的干预。  相似文献   

3D modelling of the impacts of in-stream horizontal-axis Tidal Energy Converters (TECs) on offshore sandbank dynamics     

《Applied Ocean Research》2019

The tidal energy sector is a growing industry in the UK and beyond. Energy developers’ interests are progressing towards the deployment of large arrays of tidal energy converters (TECs). Numerous factors will affect decision making related to arrays siting and size. One key factor is the effect that the TEC arrays may have on the natural sediment transport patterns and the sea bottom morphodynamics. The Inner Sound Channel located between the Island of Stroma of Pentland Firth and the Scottish Mainland (UK) has been accredited for a large-scale TEC array installation to be developed in the future. Three morphodynamically active, large sandbanks are located in the Inner Sound channel. This study investigated the impacts of tidal energy extraction from a large array of TECs on the sediment dynamics and morphology of these sandbanks. A large-scale 3D hydrodynamic and morphodynamic Delft3D model was set up to computationally model Pentland Firth, Inner Sound Channel in order to study the impacts of tidal energy extraction from a generic TEC array, on the existing hydrodynamic and morphodynamic regime. A range of hypothetical energy extraction scenarios was modelled. Results reveal that the changes to morphodynamics of these sandbanks as a result of large scale tidal energy extraction far exceeds the morphology change under the natural hydrodynamic regime and that the severity of morphology change depends on the level of energy extraction.  相似文献   

长江口南汇嘴潮滩短期冲淤演变及其动力机制研究   总被引：3，自引：2，他引：1  

赵建春  李九发  李占海  戴志军  赵军凯 《海洋学报》2009,31(4):103-111

潮滩地形的冲淤演变规律可以在一定程度上反映动力作用与地貌特征之间的相互耦合机制.根据近几年在长江口南汇嘴潮间带多断面连续观测资料,探讨区域内潮间带滩地的近期冲淤演变特征及其主要影响因子.研究结果表明:(1)南汇嘴潮滩近期主要呈现淤涨态势,而且年内过程季节性差异明显;受区位差异影响,不同观测断面的潮滩冲淤演变呈现特征不尽相同,断面1冲淤变化最为显著,年最大冲淤厚度均在10cm以上;(2)在波浪、潮流的作用下,区域内沉积物很容易被掀动悬扬,而且输沙环流系统的存在有利于悬沙向浅水区输运且在该区域内沉降淤积,从而为潮滩发育提供泥沙来源;(3)受"碧利斯"台风引起的风暴潮天气影响,研究区域内潮滩出现"大冲大淤"现象,即台风强侵蚀期过后滩面高程短期内恢复明显.由此可见,潮滩短期冲淤演变特征是各种动力因素作用下的综合体现.  相似文献   

Morphodynamic responses to the deep water harbor development in the Caofeidian sea area,China's Bohai Bay     

Yongjun Lu  Rongyao JiLiqin Zuo 《Coastal Engineering》2009

Vast bay-type tidal inlets can be found along the coastal zones of China. They are generally suitable for deep water channels and large harbors because of the presence of large water depth and good mooring conditions. The deep channel, in front of the head of Caofeidian Island in Bohai Bay, China, is a typical bay-type tidal inlet system. The tidal current, a type of reverse flow, makes the key contribution to maintain the deep water depth. The co-action of waves and tidal currents is the main dynamic force for sediment motion. Waves have significant influence on the sediment concentration. Based on the characteristics of waves, tidal currents, sediment and seabed evolution in Caofeidian sea area, a 2D mathematical model for sediment transport under influence of waves and tidal currents is developed to study the development schemes of the Caofeidian Harbor. The model has been verified for spring and neap tides, in winter as well as in summer of 2006. The calculated tidal stages, flow velocities, flow directions and sediment concentrations at 15 stations are in good agreement with the observations. Furthermore, the calculated data on pattern and magnitude of sedimentation and erosion in the related area agree well with the observations. This model has been used to study the effects of the reclamation scheme for Caofeidian Harbor on the hydrodynamic environment, sediment transport and morphological changes. Attentions are paid to the project inducing changes of flow velocities and morphology in the deep channel at the south side of Caofeidian foreland, in the Laolonggou channel and in various harbor basins. The conclusions can provide the important foundation for the protection and use of bay-type tidal inlets and the development of harbor industry.  相似文献   

Space and time variability of uncertainty in morphodynamic simulations     

A.B. Fortunato  X. BertinA. Oliveira 《Coastal Engineering》2009

The uncertainty associated with simulations of process-based coastal area morphodynamic models is assessed through numerical experimentation. Appropriate metrics of uncertainty are defined based on the standard deviation of the model results at each location and each time step. Uncertainty is examined using a set of realistic one year morphodynamic simulations of the evolution of a highly dynamic tidal inlet. Results indicate that uncertainty increases linearly with time, and suggest that its rate grows with increasing sediment fluxes. Hence, the limits of predictability of morphodynamic model applications are higher for slowly varying systems. Attempts to reduce uncertainty by aggregating model results at larger spatial scales met with limited success. Ensemble simulations are suggested as a possible avenue to investigate the long-term evolution of tidal inlets using process-based models.  相似文献   

黄河三角洲米草入侵对滩涂底栖动物多样性的影响   总被引：2，自引：0，他引：2  

申保忠  田家怡  于祥  李建庆  石东里 《海洋科学进展》2009,27(3)

2005年5,8,10月份对黄河三角洲的无棣县岔尖、东营市五号桩、小清河口米草分布区与非米草分布区底栖动物进行了调查.结果表明:米草分布区底栖动物种类少于非米草分布区的,优势种类相对多度存在差异;岔尖、小清河口米草分布区底栖动物平均密度高于非米草区的,生物量均高于非米草分布区的,但五号桩米草分布区底栖动物密度低于非米草分布区的;米草入侵导致小型螺类密度高,蛤类、蟹类密度低;岔尖、五号桩米草分布区与非米草分布区底栖动物多样性、均匀度、优势度无显著差异,小清河口则反之.米草入侵改变了底栖动物的群落结构,对小清河口底栖动物多样性影响较显著.  相似文献   

基于等高线的三角网快速构建与处理   总被引：1，自引：0，他引：1  

刘合辉  罗勇军 《测绘工程》2009,18(2):55-58

采用一种利用等高线数据,快速处理和优化TIN的方法。该方法首先将等高线离散成数据点集;然后利用凸壳技术快速地进行三角形构网;再利用TIN的拓扑结构快速内插入等高线,形成约束TIN;最后利用三角形与特征边的关系及TIN的拓扑结构,从而快速消除平坦三角形,提高TIN的质量。  相似文献   

台风对北部湾南部海底地形地貌及海底管线的影响   总被引：7，自引：0，他引：7  

董志华  曹立华  薛荣俊 《海洋技术学报》2004,23(2):24-28,34

利用旁侧声纳和多波束在不同时间段内对琼西南近岸海域进行了探测,并对台风前后的旁侧声纳资料进行了对比和分析。研究表明,琼西南近岸海域主要存在沙脊区和沙波区两种地貌类型,其中,沙波波高在1～5.5m,波长3～60m,沙脊波高在6～20m,波长2～4km。在不同年份和台风期间,沙波和沙脊存在明显的活动性,对铺设于此的海底管线构成了严重的影响。台风对小沙波起夷平作用,对较大沙波、沙脊增高加宽,并且可以使海底出现冲刷沟槽和凹坑。  相似文献   

黄海西部34°N断面潮生陆架锋的多年变化及跨锋断面的环流结构   总被引：5，自引：0，他引：5  

赵保仁  涂登志  毕亚文 《海洋科学》1992,16(2):41-45

本文分析了苏北浅滩外侧34°N断面上潮生陆架锋的多年变化,指出海上调查期间的日平均风速和大小潮变化是影响陆架锋多年变化的主要因素。本文还用诊断模式给出了横跨锋断面的环流结构。  相似文献   

崇明东北潮滩泥沙输运过程的研究     

闫天阳  葛建忠  王宪业  周在扬  陆佳玉  丁平兴 《海洋通报》2021,40(1):101-112,120

潮滩泥沙的输运过程是河口近岸泥沙输运的重要组成部分,也是诊断潮滩侵蚀-淤积的重要动力指标,特别是在地貌演变过程显著的区域更具指示意义.本研究选择长江口崇明岛东北部潮滩,在2018年3月30日-4月10日进行三脚架多参数观测,获取了高分辨率的流速、含沙量等剖面数据,运用机制分解法分析了连续21个潮周期的泥沙输运过程.结果...  相似文献