共查询到20条相似文献，搜索用时 562 毫秒
1.
2.
英国的斯珀恩角 ( Spurn Head)是由冰川侵蚀物形成的一个长 4.5km的砂砾石海岬 ,位于亨伯 ( Humber)河口。本文研究了海岬及其后面潮坪的沉积物、地形及海岸防护工程的近岸动力的影响。通过对风的数据分析 ,对波浪变浅和反射进行了模拟。通过海岬在不同气候情况下的反映 ,对河口处及潮坪区进行了海岸动力学研究 ,对海滩及潮坪的地质形态和沉积物作了评价。结果显示 ,仅仅由崖侵蚀形成的沿岸输沙的 6%是沿着海岬运输 ,主要是由波浪从北或东北部带来的 ,运移至海岬尖端砂砾石岸。中砂被东南波带过尖端在海岬内侧形成一个小区域的潮沙波。从… 相似文献
3.
4.
5.
6.
7.
8.
9.
10.
11.
A wide variety of substances, including known or potential pollutants, become associated with particles in coastal marine environments. This association may result from: (1) ion exchange, precipitation, or hydrophobic interactions with the particle surface, (2) co-precipitation with iron and manganese hydrous oxide coatings, (3) complexation with organic substances bound or aggregated with particles, (4) incorporation into mineral lattices, organisms or fecal material, or (5) flocculation of colloidal organic and inorganic matter during river and sea water mixing. The transport, accumulation and fate of such chemically-reactive pollutants in coastal marine environments are governed to a great extent by particle dynamics. Understanding of the mechanisms and processes affecting pollutant-particle associations and dynamics allows the prediction of the fate of a wide variety of pollutants in estuarine, coastal and marine environments. 相似文献
12.
Vertical structures of momentum exchange coefficient and sediment concentration are the keys in the research on estuarine and coastal suspended sediment transport. Based on the parabolic mixing length distribution pattern,the distribution pattern of vertical momentum exchange coefficient which is suitable for estuarine and coastal waters is constructed. A comparison with steady flow and measured momentum exchange coefficient during one tidal cycle in the Menai Strait of England shows that the result of this... 相似文献
13.
This paper demonstrates the importance of advective transport of water through permeable estuarine and salt marsh sediments. This transport delivers significant quantities of radium and barium to the coastal ocean; and, in some cases may remove significant quantities of uranium. These conclusions are based on repeated analyses of seven river–estuarine systems from North Carolina to Florida. Fluxes of radium and barium from these river systems are shown to be inadequate to balance the dissolved inventories of these elements in the South Atlantic Bight. The strong interactions that occur between surface and subsurface waters as these rivers encounter coastal marshes lead us to consider these river mouths as marsh-dominated in terms of their chemical fluxes to the ocean. Such interactions between the river and coastal marsh must be considered when estimating fluxes of material between the land and ocean. 相似文献
14.
河口底边界层湍流观测后处理技术方法分析 总被引：10，自引：5，他引：5
河口底边界层过程是河口海岸研究与工程应用中的重要内容。三维点式高频流速仪(ADV)已经成为湍流现场观测的最有效的工具之一,然而受测量状态、复杂的波流环境、底床几何结构等因素的影响,湍流观测的后处理目前还不成熟。在前人工作的基础上,提出了河口底边界层湍流观测后处理的综合技术方法,包括测量状态判断、数据质量检测、坐标系旋转、去除毛刺及滤波,探讨了这些处理方法中的某些步骤及处理顺序对湍流参数估算可能产生的影响,提出了综合后处理技术的准确性评估方法。该研究对于近岸海洋湍流混合、泥沙输运等重要问题的解决可以提供较为扎实的技术支持。 相似文献
15.
A tracer model with random diffusion coupled to the hydrodynamic model for the Zhujiang River Estuary (Pearl River Estuary, PRE) is to examine the effect of circulations on the transport of completely conservative pollutants. It is focused on answering the following questions: (1) What role does the estuarine plume front in the winter play in affecting the pollutants transport and its distribution in the PRE ? (2) What effect do the coastal currents driven by the monsoon have on the pollutants transport? The tracer experiment results show that: (1) the pollutant transport paths strongly depend on the circulation structures and plume frontal dynamics of the PRE and coastal waters; (2) during the summer when a southwesterly monsoon prevails, the pollutants from the four easterly river inlets and those from the bottom layer of offshore stations will greatly influence the water quality in Hong Kong waters, however, the pollutants released from the four westerly river-inlets will seldom affect the water quality of Hong Kong waters due to their transport away from Hong Kong; (3) during the winter when a northeasterly monsoon prevails, all pollutants released from the eight river gates will be laterally transported seaward inside the estuary and transport westward in the coastal waters along the river plume frontal zone. However, pollutants released from the surface layer of offshore stations near or east of the Dangan Channel will be carried into the coastal waters of Hong Kong by the landward component of the westward coastal current driven by the winter northeasterly monsoon. But the pollutants from the bottom layer of the offshore stations will be carried away from the offshore by the bottom flow driven by the northeasterly monsoon. This implies that only surface-released matter from offshore stations will affect the water quality of the coastal waters around Hong Kong during the winter when a northeasterly monsoon prevails. 相似文献
16.
A model study of influence of circulation on the pollutant transport in the Zhujiang River Estuary and adjacent coastal waters 总被引：1，自引：1，他引：1
A tracer model with random diffusion coupled to the hydrodynamic model for the Zhujiang River Estuary (Pearl River Estuary, PRE) is to examine the effect of circulations on the transport of completely conservative pollutants. It is focused on answering the following questions: (1) What role does the estuarine plume front in the winter play in affecting the pollutants transport and its distribution in the PRE? (2) What effect do the coastal currents driven by the monsoon have on the pollutants transport? The tracer experiment results show that: (1) the pollutant transport paths strongly depend on the circulation structures and plume frontal dynamics of the PRE and coastal waters; (2) during the summer when a southwesterly monsoon prevails, the pollutants from the four easterly river inlets and those from the bottom layer of offshore stations will greatly influence the water quality in Hong Kong waters, however, the pollutants released from the four westerly river-inlets will seldom affect the water quality of Hong Kong waters due to their transport away from Hong Kong; (3) during the winter when a northeasterly monsoon prevails, all pollutants released from the eight river gates will be laterally transported seaward inside the estuary and transport westward in the coastal waters along the river plume frontal zone. However, pollutants released from the surface layer of offshore stations near or east of the Dangan Channel will be carried into the coastal waters of Hong Kong by the landward component of the westward coastal current driven by the winter northeasterly monsoon. But the pollutants from the bottom layer of the offshore stations will be carried away from the offshore by the bottom flow driven by the northeasterly monsoon. This implies that only surface-released matter from offshore stations will affect the water quality of the coastal waters around Hong Kong during the winter when a northeasterly monsoon prevails. 相似文献
17.
为研究多环芳烃从河口到近海的环境归趋行为与生态风险,考察了沉积物质量浓度、溶解性有机质、温度、盐度4种典型环境因子对菲在黄河口沉积物上吸附的影响,比较了黄河口与近海两种沉积物对菲的吸附性能。研究结果表明,沉积物质量浓度越低,单位质量颗粒物的菲吸附量越高;共存的溶解性有机质对菲的吸附具有增促作用,且腐殖酸比黄腐酸的作用更显著;温度的升高不利于菲的吸附,而盐度的增加有利于菲的吸附。菲在沉积物上的吸附是分配作用与表面吸附两种行为的耦合,其中黄河口沉积物以表面吸附为主,而近海沉积物以分配作用为主。近海沉积物菲吸附量显著高于黄河口沉积物菲吸附量。基于此,菲从河口到近海的迁移过程中,更易于在沉积物表面发生吸附沉降,从而可能降低水相中的生态危害,但对近海底栖生物具有潜在的健康生态风险。 相似文献
18.
本文通过旋转平台实验室实验的方法,探讨了双河口情况下两个羽流将如何发生相互作用。在研究中,提出了一种新颖的技术对河口羽流的各切面流场进行测量,来获得河口羽流多个平面的速度场及涡度场,并基于此模拟了双河口羽流系统的准三维结构。通过对不同入流速度下的双河口羽流流场演变过程和内部结构进行了一系列对比研究,以期揭示上游河流的入流如何影响下游河口涡旋的形成及在羽流相互作用情形下各个羽流的演变。实验结果表明:随着上游入流流量的增加,上游羽流形成的沿岸流对下游河口涡旋沿岸迁移的促进和离岸输运的抑制作用将更加显著。特别是在上游入流流量等于或大于下游入流流量的情况下,下游羽流河口涡旋的体积增长明显较单一河口情况放缓。在上游入流流量较大的情况下,下游原有河口涡旋被推向更下游位置,在远离河口的位置形成另一个河口涡旋。在垂直方向上,我们可以观察到高上游入流流量条件下的下游河口涡旋的深度较小,更有利于形成三层流体的情况。本研究对多河口近海流域的营养盐及污染物的输运情况等社会和生态问题的研究有着重要的意义。 相似文献
19.
从冀鲁交界的大口河口向东至顺江沟为蜿蜒120 km的粉沙淤泥质海岸。作者先后于1987、1992和2000年对该海岸进行了多次实地考察，并应用80年代至90年代末以来的航空和卫星遥感等资料对其进行了综合分析。公元11～1128年，黄河尾闾在此摆动入海，形成河口滩型海岸。1128年以后，黄河自此迁走，在海洋动力作用下，由河口滩型海岸逐渐演变成为典型的潮滩型海岸。该岸段海岸发育了广阔平坦的、相带十分明显的潮滩地带。在潮滩上同时发育了岛链状贝壳堤、残留冲积岛和巨大的多级分叉贯通性的潮水沟网络，构成了独具特色的海岸地貌环境体系，即黄河三角洲潮滩海岸时空谱系中的古代黄河三角洲海岸。 相似文献
20.
黄河三角洲孤东及新滩海岸侵蚀机制研究 总被引：9，自引：0，他引：9
黄河三角洲孤东及新滩地区是黄河1976年以来清水沟流路河口新淤积的滩涂地带。根据孤东及新滩海域1997—2003年16个海岸剖面的实测地形资料以及利津水文站的水沙资料，阐述了黄河口尾闻改道清8出汉后，孤东及新潍海岸剖面的冲淤演变过程，并从动力地貌的角度对其冲淤过程和机制做了重点研究．结果表明，1998年以后，除新口门附近轻微淤积，其它岸段均遭到不同程度的侵蚀．清水沟老河口附近剖面表现为上冲下淤的侵蚀类型；其余侵蚀剖面形态则表现为均衡侵蚀型．近年来黄河入海水沙量的减少以及1996年河口流路的改变，调整了入海水沙、海洋动力和海岸地形之间的动态平衡，海洋动力相对增强，从而导致海岸侵蚀后退。 相似文献