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1.
长江河口横沙东滩自然演变及工程影响 总被引：5，自引：0，他引：5
横沙东滩(含横沙浅滩)是长江河口主要浅滩之一,在浅滩两侧(北港和北槽主槽)水流控制下,受浅滩横比降形成的过滩水流和较强的风浪作用影响,滩面长期以来少有淤涨。通过对1995～2002年的地形资料(吴淞基面)进行研究分析表明:从总体上看随着北港主槽向南岸进逼,造成横沙东滩窜沟西部到白条子沙之间的滩区北沿明显内凹;随着长江口深水航道治理双导堤工程的实施,在北导堤产生的堵汊、导流和拦沙的作用下,白条子沙至横沙东滩沟滩面出现微淤;而横沙东滩窜沟以东滩面难以淤高。采用促淤工程和就近吹泥上滩方式,增加横沙东滩的滩面高程以加快造地,从而达到既疏浚航道又增加湿地面积的双赢效果。 相似文献
2.
长江口横沙东滩近30年来自然演变及工程影响的GIS分析 总被引：1，自引：0，他引：1
利用长江口深水航道治理一、二期工程实施前后的地形资料,在GIS软件及相关的统计分析软件的支持下,分析了治理工程对横沙东滩冲淤演变的影响。结果表明:横沙东滩在长期的自然演变过程中滩地面积相对稳定,但20世纪90年代中期以来,由于长江来沙量减少,滩地面积出现减小的趋势;深水航道北导堤工程(1998—2000年5月)使横沙东滩的冲淤形势发生了较大的变化:横沙东滩窜沟扭曲、萎缩,白条子沙及其以东浅水区域淤积加剧;促淤工程实施后,形成了一个有利泥沙沉积的环境,过境泥沙的大量淤积及人工吹泥上滩使得横沙东滩淤长速度显著加快。 相似文献
3.
利用1986~2013年的长江口海图以及2013年九段沙上沙南沿的冲淤观测数据,分析了外沙内泓地形形成机理以及凸显的效应。长江口深水航道治理工程改变了九段沙湿地局部边界条件,导致江亚南沙沙尾下延,深泓线北移,上沙南沿坍塌后退。建议采取护滩工程措施,保护上沙湿地资源。 相似文献
4.
长江口北槽深水航道工程对九段沙冲淤影响研究 总被引：21，自引：2，他引：19
根据1989～2003年长江口九段沙附近地形图,在地理信息系统软件MapInfo的支持下,分析了北槽深水航道工程对九段沙冲淤演变的影响。在长江来沙减少总的情势下,九段沙总的淤积速率在明显下降,但北槽深水航道工程使局部冲淤形势发生逆转：九段沙顶端到江亚南沙大片区域淤积速率显著增强,沿北槽深水航道南导堤外缘形成一个10km长的淤积带;九段沙东侧水下三角洲受工程的影响不大,淤积速率持续降低并底端发生冲刷。 相似文献
5.
近年来横沙东滩围垦区前沿地形演化规律及驱动因素分析 总被引：1，自引：1，他引：0
河口大型滩涂演化关系到航运通畅、生态保护以及近岸工程的安全性，也是地貌学和工程界关注的热点。本文选择横沙东滩围垦区前沿5 m等深线包络区域作为研究区，2011–2017年间利用单波束测深系统对研究区进行持续性高精度监测，并结合近年来流域来沙、河口工程的建设和极端气候变化等影响因素分析其冲淤格局。结果表明:(1)近年来横沙东滩基本呈中间淤涨、周围冲刷的态势，整体由工程前“长大不长高”转化为工程后的“长高不长大”的演化格局；(2)海域来沙是此区域淤积的主要物源，研究区两侧涨落潮流路分异引起的环流是导致此区域淤积的主要动力；(3)深水航道堤坝工程、横沙东滩围垦工程等是导致研究区中间淤涨的原因；(4)人类活动可以直接影响滩槽的演化格局，工程建设的固定制约了河槽和滩涂的摆动，但也加剧了研究区局部的冲刷，未来应注意其内部串沟的发展，防止其连通威胁堤坝和滩涂的稳定。 相似文献
6.
长江河口区水下三角洲的稳定关系着河口区域滩涂湿地的保护、经济社会的发展,研究长江河口区水下三角洲的变化规律,制定相应的控制对策有着重要的意义。基于长江河口区水下三角洲近40年的4个测次的地形资料,采用平面形态与断面形态分析相结合的方法,探讨了长江河口区水下三角洲的变化规律和相应的控制对策。总体来看,受入海沙量减少的影响,长江河口区水下三角洲前缘10～20 m等深线之间的区域冲刷明显。崇明东滩沙体总体变化不大,横沙东滩、南汇边滩在圈围工程影响下,面积有所淤长。横沙浅滩、九段沙窜沟发育,切割洲滩,沙体稳定性受到威胁,建议对横沙浅滩、九段沙实施守护,以控制长江河口区河势稳定。 相似文献
7.
受流域来水来沙条件变化及河口大型工程建设的综合影响,长江口呈现新的冲淤格局,为预测未来演变趋势,本研究基于前期研究中建立的长江口年代际冲淤演变预测模型（Delft3D）,未来情景考虑不同来沙量条件和相对海平面上升速率。预测结果表明,到2035年长江口整体以冲刷为主,口内河段主槽和浅滩边缘冲刷较明显,仅高滩局部淤积;到2050年口内河段保持净冲刷状态,拦门沙地区在现状来沙量条件下略有淤积,但在极端低来沙量条件下转变为净冲刷状态,海平面上升对拦门沙地区冲刷具有一定抵消作用,但不会使冲淤状态产生本质改变。本研究分析认为,长江口局部区域未来冲淤趋势可能对河口综合治理与保护产生不利影响,针对新格局条件下的滩槽河势稳定、重要洲滩保护、重大工程安全评估、冲刷致灾研判以及海堤防护标准再评估等方面提出了对策建议,可为新时期长江口综合治理与可持续发展提供参考。 相似文献
8.
长江口扁担沙动力地貌变化过程研究 总被引：1，自引：0，他引：1
河口浅滩不仅为人类提供宝贵湿地资源，而且是调控河势演变的重要因素。研究河口浅滩动力地貌演变规律对航道整治、湿地生态开发及岸堤防护等具有重要价值。本文利用最近150多年的长江口历史海图资料、实测水深与水文泥沙数据，分析长江口南支最大的浅滩—扁担沙动力地貌演变格局及其变化机制。结果表明:(1) 1860?2016年期间，扁担沙反复历经淤积?冲刷?淤积，浅滩由最初水下阴滩发育出露而形成纺锤状沙体，随后演变为细长扁担状，沙尾切滩成爪状沙体，下扁担沙则伴随爪状缝隙被不断填充而淤长；(2)自1954年洪水到目前，扁担沙?2 m、?5 m等深线包络的面积与体积整体上均呈现增长态势，其中面积年均增长率分别为0.88 km2/a和0.81 km2/a，体积年均增长率分别为1.3×106 m3/a和5×106 m3/a；扁担沙浅滩在不同时期冲淤变化不同，其中1998年出现大幅度冲刷，平均冲刷厚度达到1.4 m；(3)扁担沙体积变化和长江入海泥沙的增减无直接联系，但与入海径流量的变化密切相关；(4)白茆沙“南强北弱”的河势、南北港分流工程以及东风西沙水库的建立导致扁担沙向北推移。 相似文献
9.
1959～2013年长江河口南槽动力地貌演变过程 总被引：3，自引：2，他引：1
南槽作为长江口入海四口之一,是长江水沙输运向海的主要通道。在长江入海水沙急剧变化和长江口大型涉水工程的影响下,南槽的动力地貌过程成为当前长江河口研究的重点内容之一。分析和揭示近50年来南槽的动力地貌变化过程对理解长江河口响应人类活动和自然驱动作用的变化具有重要意义。基于此,本文通过1959~2013年长时间序列的南槽地形资料,研究长江入海水沙变化及南槽落潮分流分沙比影响下的南槽动力地貌演变过程。结果表明,南槽在1989年江亚南沙并滩前后呈现两种不同的地貌演化阶段:江亚南沙并滩前,南槽普遍发生淤积,两侧浅滩不断淤涨,河槽总体呈缩小态势,河槽拦门沙呈现"双峰"状态;江亚南沙并滩后,南槽呈现出"上段冲蚀加深、中段微冲、下段河槽束窄、两侧浅滩淤积"的状态,拦门沙向"单峰"发展。此外,周边涉水工程的实施对近期南槽地貌的冲淤演变过程有较大的影响。 相似文献
10.
11.
The analysis of the structure of the cryolithozone, facies, and thicknesses of the Quaternary sediments and the results of the physicochemical mathematical modeling of the modern shelf of the western part of the Laptev Sea support the influence of the Late Pleistocene glaciations on the heat conditions and the distribution of the permafrost in the area. A ～200-m thick glacier formed under aerial conditions from atmospheric precipitation represented the metamorphosed snow cover. According to the modeling, the long-living (from 60?50 to 10?4 ky) glacier reduced the thickness of the permafrost rocks in the reviewed shelf area for 280–360 m. The Holocene marine transgression additionally decreased the thickness from 50–140 m on the inner shelf to 220–350 m on the outer shelf. The modern submarine cryolithozone 450-0 m thick is wide-spread in the studied region from the coast to the shelf boundary (isobaths of 130–140 m), where it pinches out at a distance of ～380 km from the coast at a depth of ～250 m above the sea level. 相似文献
12.
We analyze the components of the carbon system of the Sevastopol bay waters and the balance of main sediment-forming substances
using the data of field investigations in 1998–2008. The interannual variations of total inorganic carbon and the equilibrium
partial pressure of carbon dioxide in the bay water are noted. An increase in the flux of carbon dioxide into the bay and
in the content of organic carbon in bottom sediments is revealed, and an explanation of this phenomenon is given. The priority
accumulation of organic carbon in the sediments of the bay is established. We assess the interannual variation in the relative
abundances of organic and inorganic carbon as an index of the carbon cycle stability. 相似文献
13.
We generalize and analyze the state of investigations of the influence of river waters on the hydrologic structure of the
Black Sea. Specific features of the water, regime and hydrography of rivers flowing into the sea, data on the discharge of
rivers, and intrayear and interyear variability of the discharge are presented. We discuss and analyze works studying the
transformation of river waters, routes of desalinized sea waters, and their influence on the thermohaline structure and dynamic
regime of the sea.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
14.
双壳贝类血淋巴中儿茶酚胺的检测方法初步研究 总被引：1，自引：0，他引：1
研究的目的是探索一种检测双壳贝类血淋巴中儿茶酚胺含量的方法。以栉孔扇贝(Chlamysfarreri)和长牡蛎(Crassostreagigas)为实验对象,研究了取样、抗氧化剂、氧化铝用量以及Tris缓冲液用量等对实验结果的影响。结果表明,高效液相色谱电化学检测器法(HPLC-ECD)可以灵敏高效地对双壳贝类血淋巴中儿茶酚胺进行定性、定量检测。实验表明,取样时间最长不超过1.5min;还原性谷胱甘肽作抗氧化剂效果较好;前处理各试剂与血样量的最适配比为血样量1.5mL,Tris缓冲液(1.5mol/L,pH8.6)1mL和氧化铝25mg;水洗后离心并尽可能吸干氧化铝中的水分。去甲肾上腺素、肾上腺素和多巴胺的回收率分别为53%~69%、47%~73%和48%~56%。 相似文献
15.
为研究黄河入海径流变化条件下河口附近海域盐度扩散特征,以更好地保护河口海域生物资源多样性,本文以黄河下游利津水文站的长序列实测径流数据资料为基础,利用近海水动力模型FVCOM,分析径流变化对黄河口海域盐度的影响规律。结果表明：黄河口与莱州湾之间存在顺时针的环流系统,在余流作用以及涨落潮方向的影响下,黄河冲淡水长期向莱州湾扩散;丰水期黄河冲淡水几乎影响了整个莱州湾,27盐度锋可以到达莱州湾中部,27等盐线的表层包络面积为2 665.61 km2,占莱州湾的1/4左右,枯水期低盐度水只有向南扩散的趋势,27以下的低盐度水集中分布在黄河口门附近,27等盐线的表层包络面积只有199.65 km2;5月份,随着入海径流量增加,27等盐线扩散的范围、距离、方向都会发生明显变化。在对近海生物资源有迫切保护需求的情景下,适当减少其他用水户供水量以增加入海生态径流量,可以有效改善黄河口海域附近的盐度情况,为生物资源的生长繁殖创造良好条件。 相似文献
16.
V. A. Ivanov S. P. Lyubartseva N. Mikhailova N. B. Shapiro 《Physical Oceanography》2001,11(6):509-524
We analyze the results of numerical calculations performed according to the three-dimensional interdisciplinary model of an
ecological system of the Black-Sea shelf zone near the estuary of the Danube. The complete system of equations of hydrothermodynamics
is solved together with transport equations of the advection-diffusion-reaction type used to describe the transformation of
a substance (nitrogen) between the components of the characteristic vectors of the ecosystem: plankton, detritus, and biogenic
elements (nitrates). We describe the distinctive features of the circumcontinental distribution of components obtained as
a result of numerical experiments and present arguments for the conclusion that the ecosystem of the Danube estuary water
area plays the role of a buffer zone between the press of the Danubian biogenic pollutions and the neighbouring areas of the
shelf zone and open sea.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
17.
The authors have previously determined that the effectiveness and failure pattern of the ice cover caused by flexural-gravity waves generated by a submerged body motion near the bottom ice can greatly depend on the depth of the water area. In its turn, the presence of a ledge on the ice surface may affect a wave propagation pattern. This paper presents an experimental study of the bottom contour influence on the deflection and length of flexural-gravity waves. The authors describe a numerical model for the analysis of the deformed state of ice caused by hydrodynamic loads due to a submarine motion, taking into account the bottom contour. The experiments are carried out in the ice tank. The results of calculations and experiments are compared. 相似文献
18.
Ten years of semistationary studies of the interaction of the ice cover and the coastal relief of the Kandalakhsa Gulf in the White Sea allowed us to reveal the peculiarities of these processes in the warm and cold years and the mechanisms of the origination of ice forms, including ice tents, which govern the character of the tidal flats. Three dynamic fast ice zones are distinguished by their geomorphological location, morphology, and ice dynamics. The dependence of the mechanisms and volumes of the enrichment of the fast ice in the sediments on the coastal zone??s relief was established. At the coast of the Kindo Peninsula (Velikaya Salma Strait), the ice mostly contains fine-sandy sediments. Coarser sediments, including boulders, are occasional and frozen into the ice at the contact of the fast ice and the bottom. At the expense of the ice??s spreading by 4?C6 times in the warm years and 2?C4 times in the cold years, several thousand tons of sediments mostly from the tidal flat??s surface (100?C700 m3 from 1 km of coast in the wide tidal flats and <50 m3 on the steep coasts) are delivered to the water area. 相似文献
19.
Relationship between the path of the Kuroshio in the south of Japan and the path of the Kuroshio Extension in the east 总被引：2，自引：0，他引：2
A relationship between paths of the Kuroshio and Kuroshio Extension (KE) is investigated, using the satellite-derived altimetry
dataset of 1993–2008. When the Kuroshio takes the nearshore nonlarge meander path or typical large meander path and resultantly
goes through the deeper channel (about 2500 m) of the Izu-Ogasawara Ridge, the KE path adopts a relatively stable state with
the two quasi-stationary meanders. On the other hand, when the Kuroshio takes the offshore nonlarge meander path and then
passes over the shallower part of the Ridge (about 1000 m), the KE path tends to be convoluted, i.e., an unstable state. 相似文献
20.
I. E. Timchenko A. A. Primalenny V. D. Yarin E. F. Vasechkina E. M. Igumnova 《Physical Oceanography》2001,11(4):367-378
We use many-year archival observations of hydrologic and hydrobiologic state of the Sea of Azov for the identification of
the structure of a model of its ecosystem. The ecosystem model, supplemented with expert estimates of bioresource consumption
(fish reserve), contamination level, and possible ecologic fines for violation of the sea natural state, is formalized by
the method of system dynamics. Hereat, the major part of influence functions is found in terms of observational data with
application of self-organization algorithms. We also present the results of simulated experiments with the model of the ecosystem,
which enable us to analyse scenarios of its behaviour under the influence of various external factors (wind, river discharge,
water exchange with the Black Sea, etc.).
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献