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1.
By analysis of published papers on the Yangtze estuary and hydrological and sediments data in Yangshan Harbor area, many similarities
are found between Yangshan Harbor area and the Yangtze estuary. These similarities include the phenomenon of stagnating flow
areas, the distributive characteristics of the highest suspended sediment concentration areas, superficial sediments and shoal
bars. The stagnating flow area is the major similarity which causes other similarities. These similarities indicate that:
1) Turbidity Maximum and mouth bars in estuaries are mainly caused by the hydraulic balance of stagnating flow areas of estuaries;
2) The stagnating sand area of sands caused by stagnating flow area often locates on the narrower side of the stagnating flow
area; 3) The location (or shape) of fine sediments area caused by stagnating flow area reflects the location (or shape) of
the stagnating flow area. Both Yangshan Harbor area and the Yangtze estuary are the important developmental areas in the future
(man-made similarity). In-depth studies on these similarities between Yangshan Harbor area and the Yangtze estuary will have
momentous theoretical and practical significance. 相似文献
2.
洋山港海域与长江口相似性研究 总被引：11，自引：0，他引：11
根据洋山港海域的水文泥沙观测资料和长江口的研究文献分析，洋山港海域与长江口存在较多相似现象。2者均存在滞流区现象是产生其它相似现象的根本原因。即高悬沙浓度区分布特征，表层沉积特征和浅滩区分布特征的相似性是滞流区现象的衍生效应。洋山港海域与长江口的诸多相似现象揭示：（1）滞流区的动力平衡作用是最大浑浊带和拦门沙浅滩形成的主导因素；（2）滞沙区通常位于滞流区地形束窄一侧；（3）滞流区的细颗粒物质沉积区与滞流点位置（或滞流区形态）有着较为一致的吻合性，洋山港海域与长江口区间属于未来开发的热点地区，对2者的相似现象开展深入的研究将有着较深的理论和实际意义。 相似文献
3.
洋山港海域潮动力特征及其对工程的响应 总被引：2，自引：0，他引：2
距上海陆域外约32 km的洋山港是以小洋山岛链为基础建造的中国首个离岸式深水港口, 其港区陆域是通过封堵北岛链三个主要汊道并抛填成陆而成。大规模的封堵陆连工程改变了该海域的地形边界条件, 海域潮动力特征也随之响应。通过对洋山港海域堵汊陆连工程前后潮位及潮流实测资料的分析研究, 发现洋山港海域的潮动力特征主要表现在:海域潮波倍潮及复合潮增幅随工程的进行而增大, 潮动力表现出明显的非线性特征;海域中部发生壅水;海域潮波向驻波性质变异并于憩流时段引发环状流场。 相似文献
4.
5.
文章以上海洋山港工程区域为例,对其海量、多源、多尺度影像数据的组织和管理进行了初步研究。并以影像金字塔算法为基础,重点对遥感影像的分级分块、存储、索引以及影像元数据等关键技术进行了探讨。最后简要介绍了洋山港区遥感影像系统的整体架构。 相似文献
6.
随着流域和河口水利工程建设,长江河槽沉积环境发生了巨大改变,对河势演变和河槽冲淤均产生重要影响。依据长江河口河槽大面积表层沉积物采样和各河槽定点水文观测资料,分析各河槽沉积特征,探讨其影响因子及作用机制。结果表明:河槽沉积物类型以砂质粉砂和粉砂质砂分布最广,粒径分布纵向上呈自西向东减小、横向上自北向南减小趋势,河槽总体主槽粗、边滩细。涨落潮泥沙输运和沉降过程影响河槽纵向沉积分布特征,风浪作用强化了口门段河槽南北沉积环境的差异,北支、北港口门段河槽受到偏北方向风浪作用强烈,沉积物粗化明显。不同泥沙来源是造成河槽整体沉积环境差异的主导因素,南支、南港上段表现为流域来沙的沉积特征,北港、南槽、北槽则表现为流域与海域来沙的混合沉积特征,口外沉积物对口内河槽的影响主要是为口内河槽提供细颗粒物质来源。 相似文献
7.
长江河口最大浑浊带的泥沙特性和输移规律* 总被引：19，自引：0，他引：19
本文通过对不同河段的泥沙特性和输移规律的对比分析,确认长江河口来沙丰富,在河口潮流不对称和重力环流的作用下,大量泥沙向滞流点辐聚,形成最大浑浊带。最大浑浊带含沙量高,泥沙絮凝沉速快。潮流强劲,引起床沙再悬浮,输沙能力强。长江河口最大浑浊带活动区与河口拦门沙位置基本一致。本研究成果对于加深认识河口拦门沙的成因和变化,以及航槽治理具有重大的现实间义。 相似文献
8.
在全球气候变化的背景条件下,中国河口海湾生态系统的研究逐渐深入和系统化,研究热点开始关注国际公约中的重要生态敏感区,大大缩短了与国际学术界同类研究的差距。以长江口为例,由于河口海湾地区处于海洋、陆地和河流生态系统相互作用的界面上,具有开放度高、敏感度高、脆弱性高和稳定性低的"三高一低"特征。针对长江口大量滩涂栖息地被围垦和侵占的现状,提出了在长江口受损湿地构建人工替代栖息地进行人工优化的途径。中国河口海湾研究不仅需要开展国际、国内交流,还要广泛争取国际组织的资助和合作,探索跨学科、跨行业、跨地区参与动态保护管理和开发利用,使以长江三角洲为代表的中国滨海河口海湾三角洲地区的保护开发和资源利用实现可持续的生态文明。 相似文献
9.
瓯江溺谷海湾充填成陆和河口湾的形成过程 总被引：12，自引：0，他引：12
利用钻孔、考古以及文献资料,结合河口输沙的研究和河口演变的若干特点,提出了在溺谷型海湾的基础上,河口湾的形成演变和成陆过程。 相似文献
10.
北部湾北部滨海湿地水体和表层沉积物中营养元素分布与污染评价 总被引：2，自引：0，他引：2
2009年4～5月,对北部湾北部滨海湿地水体和表层沉积物进行了取样调查,研究水体中营养盐和表层沉积物中碳、氮和磷元素含量、分布及其影响因素,并在此基础上评价了滨海湿地水体富营养化水平和表层沉积物的污染状况.研究区水体中的溶解无机氮(dissolved inorganic nitrogen,DIN)、活性磷酸盐PO43-—P和化学需氧量(CODMn)平均含量分别为(211.84±37.44) μg/L、(11.01±12.11) μg/L和(0.92±0.32) mg/L;表层沉积物中总氮(TN)、总磷(TP)和总有机碳(TOC)的平均含量分别为(373±355) μg/g、(232.28±157.34) μg/g和(0.45±0.46)％.北部湾北部滨海湿地水体中的DIN含量和PO43-—P含量在茅尾海和廉州湾东部西场海区都很高,且水体富营养化比较严重,大规模的海水养殖可能是造成该现象的主要原因.研究区水体中CODMn含量空间分布呈近岸高、远岸低的特征.研究区铁山港顶部、南流江口、大风江口、钦江和茅岭江口较细的表层沉积物中的TN、TP和TOC含量较高.研究区表层沉积物的TOC/TN值分布表明,钦江口、钦州港区、防城港、企沙港区和珍珠湾东北部的沉积物有机质含量受到了强烈的陆源影响.根据加拿大安大略省环境质量评价标准,除了钦州湾顶部的龙门港区、大风江口中部和铁山港顶部西北角一小部分区域的表层沉积物中的TOC、TN和TP含量分别略高于1％、550μg/g和600μg/g,已被明显污染,而处于最低级别或严重危害级别,会对部分底栖生物产生影响外,其他绝大部分区域都属安全级别,为清洁或部分已被轻微污染. 相似文献
11.
长江河口悬浮泥沙的混合过程 总被引：2，自引：0，他引：2
根据准同步观测的悬浮泥沙及表层沉积物粒度、流速、含沙量资料, 分析了长江口及临近海域悬浮泥沙在河口的混合过程。长江河口-陆架系统悬浮泥沙中值粒径呈现“细-粗-细”的变化规律, 河口上段悬浮泥沙中值粒径为8.9 μm, 拦门沙海域为10.5 μm, 陆架区为4.5 μm, 北支为9.9 μm, 杭州湾口为5.6 μm, 泥沙类型为粘土质粉砂。河口上段和陆架区悬浮泥沙与表层沉积物的垂向混合作用较弱, 拦门沙区域二者发生强烈的混合和交换, 悬浮泥沙在由长江河口向陆架系统输移过程中仅有表层泥沙保留了流域输入的泥沙粒度特征。长江口悬浮泥沙中值粒径与含沙量呈良好的正相关关系, 水流的剪切作用是引起拦门沙海域泥沙再悬浮、近底高含沙量和悬浮泥沙粒径增加的主要原因, 悬浮泥沙粒径和含沙量的增加主要由粉砂组分的增加引起。2007 年长江河口区范围内悬浮泥沙中值粒径比2003 年普遍减小11％, 含沙量比2003 年减小22%, 河口上段含沙量对流域来沙减少的响应最为敏感, 而拦门沙区的泥沙粒径对流域来沙减少的响应最敏感。在长江流域来沙量减少的背景下, 河口拦门沙区域仍能维持较高的含沙量, 主要缘于河口系统内部的供沙 相似文献
12.
近年来长江流域入海沙量呈现阶梯性减小趋势,三峡水库蓄水后加剧了这一减小趋势,并通过传递效应影响河口悬沙浓度变化。基于长江口1950-2013年悬沙浓度数据,结果表明：① 长江口南支河段及口外海域悬沙浓度为减小趋势,且越向海域减幅越小,同时与流域入海沙量减幅差距加大;② 北支优势流变化不大,但悬沙浓度为减小趋势,主要为南支和海域大环境悬沙浓度减小所致;③ 拦门沙河段悬沙浓度的峰值区域因径流减小、潮流相对增强,2003-2012年较1984-2002年期间峰值位置向口内上溯约1/6经度,上溯距离洪季 > 年均 > 枯季;④ 1999-2009年南槽进口悬沙浓度减小,主要是再悬浮和滩槽交换引起的悬沙浓度增量小于流域和海域悬沙浓度锐减引起的减量,中段该作用相反,悬沙浓度为增加趋势;⑤ 北槽进口由于分流分沙比减小、流域和海域悬沙浓度减小及再悬浮量减小等综合影响下,1999-2012年逐年的8月份悬沙浓度呈减小趋势,中段越堤沙量作用明显高于外部坏境引起的减小量,为增加趋势。 相似文献
13.
The synchronicity and difference in the change of suspended sediment concentration in the Yangtze River Estuary 总被引：2，自引：1，他引：1
The sediment discharge from the Yangtze River Basin has a stepwise decreasing trend in recent years. The impounding of the Three Gorges Reservoir exacerbated this decreasing trend and affected the change of the suspended sediment concentration (SSC) in the Yangtze River Estuary through the transmission effect. The SSC data of the Yangtze River Estuary during 1959-2012 showed that: (1) The SSC in the South Branch of the Yangtze River in the estuary and in the off-shore sea area displayed decreasing trends and decreased less towards the sea. At the same time, the difference in decreasing magnitude between SSC and sediment discharge became bigger towards the sea. (2) For the North Branch the preferential flow did not change much but the SSC tended to decrease, which was mainly caused by the decrease of SSC in the South Branch and China East Sea. (3) Due to the decreased runoff and the relatively strengthened tide, the peak area of the SSC in the bar shoal section in 2003-2012 moved inward for about 1/6 longitude unit compared with that in 1984-2002, and the inward-moving distance was in the order of flood season > annual average > dry season. (4) In the inlet of the South Passage, the SSC decreased mainly because the increase caused by resuspension and shore-groove exchange was less than the decrease caused by the sharp SSC decrease in the basin and the sea areas. The reverse was true in the middle section, where the SSC showed an increasing trend. (5) In the inlet of the North Passage, under the combined influence of decreased flow split and sediment split ratios, the decreased SSC in the basin and the sea area and decreased amount of resuspension, the SSC displayed a decreasing trend. In the middle section, because the increased amount caused by sediment going over the dyke was markedly more than the decreased amount caused by external environments, the SSC tended to increase. Holistically, the sharp decrease in sediment discharge caused synchronized SSC decreases in the Yangtze River Estuary. But there were still areas, where the SSC displayed increasing trends, indicating synchronicity and difference in the response of SSC to the sharp decrease in sediment discharge from the basin. 相似文献
14.
The mouth bar in the Yangtze estuarine waterways has a significant influence on navigational transport within the estuary,flood discharge and construction of the Shanghai Port.In this paper the morphological evolution and mechanisms of mouth bar formation of the Yangtze estuarine waterways are studied by analyzing hundreds of years of historical data and the latest profile maps of some or the main mouth bar channels in the Yangtze Estuary.The results are shown as follows:The mouth bars in the North Branch have moved gradually from outside the mouth to the inside and formed a huge sand bar.In the North Channel,the head of the mouth bar has migrated about 30 kilometers downstream,and a channel bar has been developing since 2001.Two mouth bar tops,which always existed in the North Passage,disappeared in 2010.The head of the mouth bar in the South Passage has migrated downstream about 14 km and the number of tops increased at first but is reduced to only one now.According to the results,we can conclude that the evolution of the mouth bars differs depending on their location.In the North Branch it is directly related to large-scale reclamation in Chongming Island,but in the North Passage it has a close relationship with regulation of the Yangtze Estuary Deepwater Channel.However,the evolution of mouth bars in the North Channel and South Passage is not only connected with the Yangtze Estuary Deepwater Channel Regulation Project,but also with the reclamation in the East Hengsha Shoal and the closure of the Qingcaosha Reservoir. 相似文献
15.
上海洋山深水港建设的地域空间作用分析 总被引：1，自引：0，他引：1
论述上海洋山深水港的建港条件及其港区工程组合特征,分析洋山港建成后的地域空间作用。建成后的洋山港水深达15 m以上,并由32.5 km长的东海大桥连接洋山深水港区和上海芦潮港物流园区,可以解决上海河口港不能停靠第五、六代集装箱船的问题,改变了上海港的格局。同时提高了上海国际航运中心在东北亚地区港口中的竞争力,带动了长江三角洲、长江流域及全国的经济发展。 相似文献
16.
基于长江河口1959-2011 年实测悬沙浓度数据,通过对河口最大浑浊带外围海域泥沙要素分析的基础上,研究了近期流域人类活动和河口整治工程对最大浑浊带悬沙浓度的影响。研究表明:① 流域人类活动对入海水量影响较小,无明显趋势变化,而沙量和含沙量呈现锐减趋势,也使得进入河口区域的泥沙量呈现一致锐减;② 长江口外海域和南部杭州湾海域悬沙浓度变化不大,北部苏北沿岸略有减小,因数值较长江口海滨区小约1 个数量级,对浑浊带影响较小;③ 最大浑浊带位置受径流和潮流控制,面积变化与入海沙量多寡关系密切;④ 整个浑浊带区域悬沙浓度受入海沙量锐减决定,2000-2009 年较1959-1999 年悬沙浓度减小约为24.73%,向海延伸减幅降低,且峰值区域向口内移动,泥沙再悬浮作用对维持最大浑浊带悬沙浓度起调节作用,但不能决定其锐减趋势;⑤ 北槽航槽最大浑浊带的悬沙浓度向海为低—高—低变化特点,受入海沙量锐减、北槽分流分沙比减少及床沙粗化等影响,使其上段和下段悬沙浓度减小趋势,而中段受南导堤越堤沙量的影响悬沙浓度呈增加趋势。 相似文献
17.
近百年来长江河口航道拦门沙的形态演变特征 总被引：2，自引：0，他引：2
长江河口航道拦门沙对长江航运、泄洪以及上海港的建设具有重大的影响。通过近百年来历史资料和最新图件中北支、北港、北槽和南槽拦门沙河段的主泓剖面与平面图,分析近百年来4 个入海航槽拦门沙的形态演变特征。经分析发现：近100 年来,北支拦门沙由口外向口内逐渐移动并演变为口内巨型沙坎;北港拦门沙滩顶向下游移动了近30 km,2001 年后北港拦门沙河段开始有心滩发育;北槽拦门沙有两个明显的滩顶,但至2010 年这一显著特征消失;南槽拦门沙滩顶呈双峰型-多峰型-单峰型变化趋势,且滩顶向下游移动了约14 km。显然,除了北支拦门沙演变与崇明岛大规模围垦、北槽拦门沙演变与深水航道直接相关外,北港、南槽拦门沙演变特征主要与长江深水航道整治工程、横沙东滩圈围以及青草沙水库等大型工程影响有关。 相似文献
18.
分汊型河床的形成与演变——以长江中下游为例 总被引：8，自引：0，他引：8
本文根据多年的地质、地貌,来水来沙等考察资料,河道变迁的历史记载以及实验研究成果,分析了分汊型河床的两个必要条件及三方面的演变特征,最后用河流力图使自己的能量损耗率达于最小的假说对汊河的形成和演变作了解释。 相似文献
19.
A detailed analysis of suspended sediment concentration (SSC) variations over a year period is presented using the data from 8 stations in the Yangtze River estuary and its adjacent waters, together with a discussion of the hydrodynamic regimes of the estuary. Spatially, the SSC from Xuliujing downwards to Hangzhou Bay increases almost constantly, and the suspended sediment in the inner estuary shows higher concentration in summer than in winter, while in the outer estuary it shows higher concentration in winter than in summer, and the magnitude is greater in the outer estuary than in the inner estuary, greater in the Hangzhou Bay than in the Yangtze River estuary. The sediments discharged by the Yangtze River into the sea are resuspended by marine dynamics included tidal currents and wind waves. Temporally, the SSC shows a pronounced neap-spring tidal cycle and seasonal variations. Furthermore, through the analysis of dynamic mechanism, it is concluded that wave and tidal current are two predominant factors of sediment resuspension and control the distribution and changes of SSC, in which tidal currents control neap-spring tidal cycles, and wind waves control seasonal variations. The ratio between river discharge and marine dynamics controls spatial distribution of SSC. 相似文献
20.
长江口水域悬沙浓度时空变化与泥沙再悬浮 总被引：4，自引：0，他引：4
A detailed analysis of suspended sediment concentration (SSC) variations over a year period is presented using the data from 8 stations in the Yangtze River estuary and its adjacent waters, together with a discussion of the hydrodynamic regimes of the estuary. Spatially, the SSC from Xuliujing downwards to Hangzhou Bay increases almost constantly, and the suspended sediment in the inner estuary shows higher concentration in summer than in winter, while in the outer estuary it shows higher concentration in winter than in summer, and the magnitude is greater in the outer estuary than in the inner estuary, greater in the Hangzhou Bay than in the Yangtze River estuary. The sediments discharged by the Yangtze River into the sea are resuspended by marine dynamics included tidal currents and wind waves. Temporally, the SSC shows a pronounced neap-spring tidal cycle and seasonal variations. Furthermore, through the analysis of dynamic mechanism, it is concluded that wave and tidal current are two predominant factors of sediment resuspension and control the distribution and changes of SSC, in which tidal currents control neap-spring tidal cycles, and wind waves control seasonal variations. The ratio between river discharge and marine dynamics controls soatial distribution of SSC. 相似文献