射阳港拦门沙演变规律探讨

根据实测资料分析发现,射阳港拦门沙具有一年内随烘、枯水期不断南北往复摆动、而多年总体向北偏移和水深逐渐变深的变化规律：其演变是射阳河口建挡潮闸,下泄径流量及河道纳潮量变化、潮波变形和废黄河口泥沙沿岸运移所致,对船舶航行和港口建设有参考意义。     

基于遥感和GIS的辽河口拦门沙演变研究

河口拦门沙浅滩冲淤演变对于河口生态环境保护及资源开发利用等具有十分重要的意义。以辽河口拦门沙地带为研究对象,采用遥感和GIS相结合的方法,克服了实测地形资料缺乏的困境,对辽河口拦门沙的冲淤演变特征进行了研究,并探讨了演变的原因机制。研究结果表明：近期辽河口拦门沙外缘整体呈侵蚀后退趋势,这主要与流域来沙减少有关;蛤蜊岗子滩和西滩都有向东淤涨的趋势,这与拦门沙外缘侵蚀的泥沙向上游搬运及局部河势变化产生的泥沙输移有关;辽河干流水道内江心洲不断向下游淤涨,对局部河势及拦门沙浅滩的演变会产生较大的影响。     

黄河口拦门沙与盐水楔特征及其演变

黄河口存在一个成型堆积法，称拦门沙。多次实测结果，其长度约３－７ｋｍ同蛋白质水平宽度与河宽相同，横亘于黄河尾闾与海水相连接处。随着河口延伸，拦门沙也向海推移，淤积最多的 部位是前绝急坡区。     

射阳港拦站沙演变规律探讨

根据实测资料分析发现,射阳港拦门沙具有一年内随洪、枯水期不断南北往复摆动、而多年总体向北偏移和水深逐斩变深的变化规律;其演变是射阳河口建挡潮闸,下泄径流量及河道纳潮量变化,潮波变形和废内河口泥沙沿岸运移所致,对船舶航行和港口建设有参考意义。     

黄河口拦门沙研究动态

拦门沙是径流输沙运移过程中,在河口附近,由于能量释放,河流动力与海洋动力及其泥沙自身重力相互作用,咸淡水混合,发生絮凝而沉降在河口附近的隆起沙体,是海与陆相互作用的产物。河口拦门沙的存在,不但阻碍了黄河的排洪、泄沙和泄凌,而且因其特殊的水沙条件造成河口区河道改道频繁,对航运     

MapInfo在黄河口拦门沙研究中的应用

根据MapInfo所具有的功能特点,讨论了MapInfo在黄河口拦门沙中的应用.在黄河口拦门沙的研究中,通过使用MapInfo软件,使我们对拦门沙的研究从定性走向定量,从简单的文字描述达到直观的地图展示,为拦门沙的研究提供了一种新的手段.     

中国主要河口拦门沙的研究进展

河口拦门沙常处在河流入海的咽喉部位 ,是海陆相互作用的产物 ,也是河口水沙与河床作用最剧烈的地带 ,曾经引起众多学者的广泛关注。由于河道突变 ,拦门沙因水浅给河流水运和海运事业的发展以及通海航槽建设带来了极大的影响 ;此外 ,由于拦门沙水域特殊的理化性质 ,使得其在河口地球化学过程和河口生态系统中起着不可替代的作用。所以 ,对于河口拦门沙的研究受到了广泛的重视 ,取得了很大的进展 ,本文对于国内在河口拦门沙研究方面所取得的进展进行评述。１拦门沙发育演变及形态特征拦门沙是河口中主要的地貌单元 ,从６０年代以来 ,我国许多…     

闽江口拦门沙砂体的演变及其沉积年代

本文介绍了闽江口拦门沙砂体的~(14)C年代、沉积速率、堆积趋势及其变化,从历史的演变规律推测现代闽江口拦门沙砂体堆积的可能发展趋势,指出航道整治的重点地段。     

Morphological evolution of a large sand bar in the Qiantang River Estuary of China since the 1960s

A large sand bar develops in the inner Qiantang River Estuary, China. It is a unique sedimentary system,elongating landwards by about 130 km. Based on long-term series of bathymetric data in each April, July, and November since the 1960 s, this study investigated the morphological behavior of this bar under natural conditions and the influence of a large-scale river narrowing project(LRNP) implemented in the last decades. The results show that three timescales, namely the seasonal, interannual a...     

莱州湾东部沙波地貌分布特征及其形成演化

由2009年海底地形地貌调查资料,对莱州湾东部海底沙波的分布和形成进行探讨研究。结果发现：该地区发育大面积海底沙波地形,沙波主要为二维直线型沙波,陡峭度为0．001,对称指数为1．2,对称指数较好。沙波的形成和海底坡度以及水深有密切关系,在平坦海底易于形成,且与水深有一定的负相关关系。莱州湾东部沙波是10m等深线的古海...     

珠江口伶仃洋泥沙运动的沉积动力作用

珠江口伶仃洋是个多口门汇入的河口湾,其泥沙来源复杂多样,既有陆域来沙,又有海域来沙,这些泥沙进入伶仃洋以后,在径流作用、潮流作用、盐淡水混合作用及风浪等的影响下,不断地运移,形成“三滩两槽”的分布格局,７－年代中期以后,由于东部潮流作用及盐淡水混合作用的加强,受其压迫,西部泥沙物质不断向南、东南方向输运与沉积。     

珠江口黄茅海冬季海洋生态环境特征

根据2007年12月在珠江口西部黄茅海的调查采样,对该海域的叶绿素a、初级生产力(C)、浮游动、植物进行了初步的研究.分析了浮游动、植物的种类组成、群落结构、数量和生物景等.结果表明,叶绿素a浓度和初级生产力(C)均值分别为2.75 mg/m3和61.16 mg/m2·d.浮游植物共有43种,以硅藻为主,绝对优势种为颗粒直链藻,平均细胞丰度为20.1×104 cell/m3,以近海广布种为主要类群,多样性指数和均匀度均值分别为2.59和0.73.浮游动物共有57种,暖水种沿岸类群种类占大多数,以丹氏纺缍水蚤为绝对优势种,平均丰度和牛物量分别1 850 ing/m3和679.74 mg/m3,多样性指数和均匀度均值分别为2.92和0.63.     

Shoreline accretion and sand transport at groynes inside the Port of Richards Bay

The south-western shoreline along the entrance channel inside the Port of Richards Bay has experienced continued erosion. Four groynes were constructed to stabilise the shoreline. Monitoring of shoreline evolution provided valuable data on the accretion adjacent to two of the groynes and on the sediment transport rates at these groynes. Tides, beach slopes, winds, wave climate, current regime, and sand grain sizes were documented. The one site is “moderately protected” from wave action while the other is “protected” according to the Wiegel [Wiegel, R. L. (1964). Oceanographical engineering. Prentice Hall, Inc., Englewood Cliffs, NJ.] classification. The shoreline accreted progressively at the two groynes at 0.065 m/day and 0.021 m/day respectively. The shorelines accreted right up to the most seaward extremity of the groynes. Equilibrium shorelines were reached within about 3.5 years to 4 years, which compare well with other sites around the world. The mean wave incidence angle is large and was found to be about 22°. The median sand grain sizes were 0.33 mm and 0.37 mm. The groynes acted as total traps, the beach surveys were extended to an adequate depth, and cross-shore sediment transport did not cause appreciable net sand losses into the entrance channel. The net longshore transport rate along the study area, which is north-westbound, is only slightly lower than the gross longshore transport. The actual net longshore transport rates are 18 000 m³/year and 4 600 m³/year respectively at the two groynes. A rocky area limits the availability of sand at one groyne. There is fair agreement between the predicted and measured longshore transport rates at the other groyne.     

Multiple longshore sand bars in the upper Chesapeake Bay

In the upper Chesapeake Bay (Maryland, U.S.A.) field surveys were conducted at 18 multiple longshore sand bar sites. The multiple bar systems were found in water depths less than approximately 2 m (mean sea level), and exhibited mild bottom slopes of 0·0052 or less. The number of bars composing each system ranged from four to 17 and the spacing between the crests typically increased in the offshore direction, ranging from 12 to 70 m. Bar height also typically increased with distance offshore and ranged from 0·03 to 0·61 m. A grain size analysis of crest and trough sediment did not reveal any significant differences and the sediment was categorized as ‘fine sand’. A review of the literature data indicated that the Chesapeake Bay multiple bars possessed similar characteristics to those found in Gelding Bay (Baltic Sea); similarities in fetch, wave height and tidal range between the two bays may account for this finding. The surf-scaling parameter indicated that the multiple bar systems were extremely dissipative with regard to wave energy, and wave height appeared to be an important factor in controlling bar spacing and bar height. A multiple wave break point hypothesis was discussed as a possible mechanism for the formation of Chesapeake Bay multiple longshore bars, and limited observational evidence appeared to support such a mechanism.     

沙洲并陆与长江口北部岸线的演变

全新世以来，长江口北岸南通－扬州南部经历了“浅海－陆地”的成陆过程。4ka，B.P．前，本区为一漏斗形的浅水海湾，河口拦门沙极为发育.4ka.B.P。以来，沙洲并岸，河口陆地淤长，长江口北部岸线呈东南延伸之势。     

珠江河口特征认知的发展

人们对珠江河口的认知发生过几次飞跃。第一次认知飞跃,柯维廉（W.Olivecrona）1915年首次提出了珠江三角洲的概念;第二次认知飞跃,吴尚时1937年证明海水曾深入广州形成珠江河口湾并发育三角洲,1941和1947年先后著文肯定了珠江三角洲的存在,并确定了其主体范围;第三次认知飞跃,曾昭璇1980年提出了冲缺三角洲的概念,1997年提出了串珠状冲缺三角洲发育模式,揭示了珠江三角洲发展的时间与空间位置;第四次认知飞跃,赵焕庭1982年揭示了珠江三角洲叠置晚更新世晚期老三角洲与全新世中期现代三角洲,新资料显示还存在晚更新世中期三角洲;第五次认知飞跃,赵焕庭等于1973-1982年间运用西蒙斯优势流概念和河口盐水楔理论研究了口门和河口湾滩槽地形的发育演变;第六次认知飞跃,吴超羽等于2006年创造性应用自己研发的长周期机理模型和沉积学、地貌动力学等多学科互证,量化再现了珠江三角洲6~2.5 ka BP"镶嵌式"演变过程。     

珠江口伶仃洋滩槽发育演变影响因素的分析

珠江口伶仃洋汇集了虎门、蕉门、洪奇沥、横门的来水来沙,这些水、沙进入伶仃洋后,在各种因素的综合作用下,不断地运移,造成今天的伶仃洋三滩两槽复杂的水下地形。