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1.
基于海洋站潮位观测和中国沿海海平面变化影响调查等数据,分析了辽东湾沿岸海平面变化及海岸侵蚀状况,并定量评估了未来海平面上升情景下,辽东湾两岸典型沙质海岸侵蚀影响和沙滩养护投入。分析预测和评估结果表明:1980-2017年,辽东湾沿海海平面上升速率为3.0 mm/a,其中辽东湾东岸沿海海平面上升速率明显高于西岸。2009-2017年,辽宁营口白沙湾、绥中网户、绥中南山港和绥中团山气象观测场岸段后退和下蚀较为严重,部分岸段滩肩蚀退达2～3 m/a。预计2100年,辽东湾沿海海平面上升幅度在20～48 cm之间,由海平面上升引发的辽东湾海岸侵蚀土地损失为23.1 km2,土地经济损失为1410万元。为减缓海岸侵蚀,旅游沙滩和一般沙滩养护总投入分别为11亿元和46亿元,全岸段养护成本较高,应选取旅游沙滩等重点岸段进行养护。 相似文献
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辽河三角洲地区海平面上升趋势及其影响评估 总被引：11，自引：1，他引：10
根据潮位资料分析,辽河三角洲平原和辽东湾东岸近四五十年来相对海平面处于上升趋势,从70年代以来平均每年上升量为5mm左右.考虑到辽河三角洲平原地面下沉以及全球性海平面将加速上升,预计下个世纪内,辽河三角洲平原相对海平面上升的速率将达到8-10mm/a,到2050年相对海平面上升量将达到40～55cm.利用遥感和地理信息系统,对不同的海平面上升量将造成的土地淹没损失进行了预测.如不加防护,相对海平面上升0.5m时,将淹没近4000km2,包括整个营口市区和半个盘锦市区;上升1.0m时,将淹没5000km2.对海平面上升将造成海岸侵蚀、风暴潮和洪涝等灾害加剧等影响也进行了分析. 相似文献
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为保护亚龙湾砂质海岸及其生态系统,文章采用2016年和2019年的监测数据以及2008年的历史数据,依据相关技术标准和方法,从岸线后退速率和岸滩下蚀速率2个方面综合评价亚龙湾砂质海岸的侵蚀状况和侵蚀强度,并分析其原因。研究结果表明：亚龙湾砂质海岸存在持续性较强且较严重的海岸侵蚀;2008-2016年岸线后退速率和年均土地损失面积分别约为-1.00 m/a和2 080 m2,2016-2019年岸线后退速率和年均土地损失面积分别约为-1.80 m/a和9 836 m2,亚龙湾海岸侵蚀有明显加剧的趋势;2016-2019年亚龙湾东部和西部海岸的岸滩下蚀速率分别约为-13.3 cm/a和-36.2 cm/a,西部岸滩下蚀速率远高于东部岸滩;亚龙湾全段为强侵蚀等级,其中东部岸段为强侵蚀等级,西部岸段为严重侵蚀等级;造成亚龙湾海岸侵蚀的原因主要包括海岸工程建设、植被破坏和海平面上升。 相似文献
4.
粤西海岸全新世中期以来海平面升降与海岸沙坝潟湖发育过程 总被引：3，自引：0，他引：3
沙坝湖海岸是一种重要的海岸类型。文章论述了粤西海岸全新世中期以来在海平面升降影响下沙坝湖地貌的发育过程,得出如下结论：距今7000a至5000a．海平面曾上升至＋4m,由于大陆架泥沙的向陆堆积,形成了揭湖拦湾沙坝的后缘高突部分：以后海平面逐步下降至现今位置,它所形成的海退沙楔发育成低矮的向海沙坝和海滩;距今2000a,海平面趋于相对稳定;现今海平面微升,出现了海岸侵蚀。文章还对该地在海平面升降影响下的海岸泥沙运移机制以及海岸高海面堆积和现今海岸侵蚀现象作了解析。 相似文献
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广西北海银滩侵蚀及其与海平面上升的关系 总被引：2，自引：0，他引：2
基于历史图件对比方法和Bruun法则对广西北海银滩岸线的侵蚀进行评估和预测.结果表明银滩在近30a内海岸侵蚀达10.40 m/a,其中人类活动作用是造成海岸侵蚀的主要因素,人类活动对岸线位置蚀退的影响贡献为98%;海平面上升导致岸线蚀退的贡献仅为2%.然而,在未来100 a内,基于历史图件对比分析估算的银滩侵蚀宽度可能超过1 000 m,银滩环境将会发生退化.因海平面上升而对岸线蚀退的贡献权重增加为9%.由于人类活动导致的银滩退化可以进行控制和预防,故对未来海平面上升引发的银滩环境退化应该予以重点关注. 相似文献
8.
海岸侵蚀和海岸线管理的初步研究 总被引：20，自引：0，他引：20
在我国30 000km多的海岸线上海岸侵蚀后退问题相当普遍，海岸的后退侵蚀给沿海地区造成了严重的危害，近处来随着海平面上升及河流径流量减少引起入海泥沙量减少，海岸侵蚀有不断加剧的趋势，海岸线管理就是针对海岸锓蚀而提出来的一项管理政策。本文在对中国海岸侵蚀原因分析的基础上，结合国外成功的岸线管理经验提出了关于海岸线侵蚀管理中的若干概念、海岸线管理的技术和理论支持以及海岸带立法和海岸线管理程序。 相似文献
9.
根据 Bruun法则 ,通过大量的试验证明了路易斯安娜障壁岛海平面的上升是其海岸快速侵蚀的一个重要原因 ,说明正在发生侵蚀的路易丝安娜障壁岛的滨面砂粒级沉积物所占比例较低。在 1 9世纪 80年代、2 0世纪 3 0年代和 80年代利用探测技术探测了密西西比河三角洲沿西部海岸线 1 50 m的海岸剖面。应用 RMS标准观察平衡剖面是否一直在测试的年代中保持不变。只有大约一半的测试剖面符合平衡面标准 ,表明 Bruun法则应用范围有一定的局限性。在研究范围内的 3 7个点中 ,利用符合平衡面标准的剖面和测得的相对海平面上升数据来测量海岸线后退速率… 相似文献
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莱州湾南岸海岸侵蚀过程与原因研究 总被引：18，自引：0，他引：18
采用历史资料对比分析的方法,对莱州湾南岸1958-2004年的海岸侵蚀进行了研究。结果表明,1958-1984年,莱州湾南岸岸线平均侵蚀后退速率为27 m/a,0 m等深线后退速率为27~65 m/a,岸滩平均蚀低速率为2.1 cm/a。1984-2004年,莱州湾南岸岸线位置基本无变化,岸滩平均蚀低速率为1.04 cm/a,水深5 m以浅的区域表层沉积物变粗。海面相对上升、入海泥沙量减少和风暴潮是研究区海岸侵蚀主要原因,三者对海岸侵蚀影响权重比为3∶5∶2。 相似文献
11.
Donald L. Forbes George S. Parkes Gavin K. Manson Lorne A. Ketch 《Marine Geology》2004,210(1-4):169-204
Storms play a major role in shoreline recession on transgressive coasts. In the southern Gulf of St. Lawrence (GSL), southeastern Canada, long-term relative sea-level rise off the North Shore of Prince Edward Island has averaged 0.3 m/century over the past 6000 years (>0.2 m/century over 2000 years). This has driven long-term coastal retreat at mean rates >0.5 m/a but the variance and details of coastal profile response remain poorly understood. Despite extensive sandy shores, sediment supply is limited and sand is transferred landward into multidecadal to century-scale storage in coastal dunes, barrier washover deposits, and flood-tidal delta sinks. Charlottetown tide-gauge records show mean relative sea-level rise of 3.2 mm/a (0.32 m/century) since 1911. A further rise of 0.7±0.4 m is projected over the next 100 years. When differenced from tidal predictions, the water-level data provide a 90-year record of storm-surge occurrence. Combined with wind, wave hindcast, and sea-ice data, this provides a catalogue of potentially significant coastal storms. We also document coastal impacts from three recent storms of great severity in January and October 2000 and November 2001. Digital photogrammetry (1935–1990) and shore-zone surveys (1989–2001) show large spatial and temporal variance in coastal recession rates, weakly correlated with the storm record, in part because of wave suppression or coastal protection by sea ice. Large storms cause rapid erosion from which recovery depends in part on local sand supply, but barrier volume may be conserved by washover deposition. Barrier shores with dunes show high longshore and interdecadal variance, with extensive multidecadal healing of former inlet and overwash gaps. This reflects recovery from an episode of widespread overwash prior to 1935, possibly initiated by intense storms or groups of storms in the latter half of the 19th century. With evidence from the storms of 2000–2001, this points to the importance of storm clustering on scales of weeks to years in determining erosion vulnerability, as well as the need for a long-term, large-scale perspective in assessing coastal stability. The expected acceleration in relative sea-level rise, together with projections of increasing storm intensity and greatly diminished winter ice cover in the southern GSL, implies a significant increase in coastal erosion hazards in future. 相似文献
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Stephen P. Letherman 《Progress in Oceanography》1987,18(1-4)
Sea-level is one of the principal determinants of shoreline position. Sea-level rise induces or accelerates on-going shore retreat since deeper water decreases wave refraction, thus increasing littoral drift, and also allowing waves to arrive closer to shore before breaking. Tidal records from the US East and Gulf coasts indicate a relative sea-level rise of approximately 0.3m has occurred during the past century. Concomitantly, erosion has been prevalent almost everywhere along these sandy shorelines. Ocean City, Maryland, was selected as a case study site to determine historical shoreline changes and to project future beach erosion based on accelerated rates of sea-level rise. During the past 130 years (1850–1980), this shore has retreated approximately 75m and many highrise buildings at Ocean City are now threatened during storm conditions. Accelerated sea-level rise is expected to increase the rate of retreat by a factor of 2 to 5 based on analysis of present trends. This significantly reduces the planning time available for mitigating the hazard and increases the vulnerability of this urbanised barrier through time. 相似文献
13.
I. O. Leont’yev 《Oceanology》2012,52(5):700-709
The proposed algorithm comprises three main steps. The first step is the evaluation of the sediment transport and budget. It was shown that the root segment of the Vistula Spit is dominated by eastward longshore sediment transport (up to 50 thousand m3/year). Over the rest of the spit, the shoreline??s orientation causes westward sediment transport (more than 100 thousand m3/year). The gradients of the longshore and cross shore sediment transport become the major contributors to the overall sediment balance. The only exception is the northeastern tip of the spit due to the appreciable imbalance of the sediment budget (13 m3m?1 yr?1). The second step in the prediction modeling is the estimation of the potential sea-level changes during the 21st century. The third step involves modeling of the shoreline??s behavior using the SPELT model [6, 7, 8]. In the most likely scenario, the rate of the recession is predicted to be about 0.3 m/year in 2010?C2050 and will increase to 0.4 m/year in 2050?C2100. The sand deficit, other than the sea-level rise, will be a key factor in the control of the shoreline??s evolution at the northeastern tip of the spit, and the amount of recession will range from 160 to 200 m in 2010?C2100. 相似文献
14.
Deposystems are complex and governed by discrete depo events with variable intervals of stasis or erosion in between. Since shoreface sediments indicate sea level, depo events of shoreline facies are discrete samples of sea level. Only if these samples are sufficiently regular and frequent will the shoreline trajectory in the space domain accurately reflect the sea-level curve in the time domain. This study presents a method to convert shoreline trajectory in the space domain to sea-level curve in the time domain from artificial miniature deltas. One obtains the depo sequence as function of time and uses it to: convert depo sequence from time-to space domain, correlate depo sequence to shoreline trajectory in the space domain, and convert shoreline trajectory from space-to time domain. For natural deltas one would extract the depo set in the frequency domain, i.e. the probability density function of stasis intervals between depo events from the experimental depo sequence and use it to: convert shoreline trajectory from space-to time domain, and infer a range of possible sea-level curves. This method therewith explicitly includes the uncertainty of the inferred sea-level curve. 相似文献
15.
Accelerated relative sea-level rise and rapid coastal erosion:: testing a causal relationship for the Louisiana barrier islands 总被引：1，自引：0，他引：1
Jeffrey H. List Asbury H. Sallenger Jr. Mark E. Hansen Bruce E. Jaffe 《Marine Geology》1997,140(3-4):347-365
The role of relative sea-level rise as a cause for the rapid erosion of Louisiana's barrier island coast is investigated through a numerical implementation of a modified Bruun rule that accounts for the low percentage of sand-sized sediment in the eroding Louisiana shoreface. Shore-normal profiles from 150 km of coastline west of the Mississippi delta are derived from bathymetric surveys conducted during the 1880s, 1930s and 1980s. An RMS difference criterion is employed to test whether an equilibrium profile form is maintained between survey years. Only about half the studied profiles meet the equilibrium criterion; this represents a significant limitation on the potential applicability of the Bruun rule. The profiles meeting the equilibrium criterion, along with measured rates of relative sea-level rise, are used to hindcast shoreline retreat rates at 37 locations within the study area. Modeled and observed shoreline retreat rates show no significant correlation. Thus, in terms of the Bruun approach, relative sea-level rise has no power for hindcasting (and presumably forecasting) rates of coastal erosion for the Louisiana barrier islands. 相似文献
16.
带周期项的海平面变化灰色分析模型及广西海平面变化分析 总被引：7，自引：0，他引：7
提出了一种带周期项的海平面变化灰色分析模型.该模型保持了GM(1,1)模型能较好反应海平面变化趋势的优点,不仅能求出海平面变化速率,还能方便求出海平面变化的加速度,同时,该模型能较好的模拟海平面变化中的周期现象,从而克服了GM(1,1)不能预报周期性显著的月平均海面的缺点,并提高了预报精度.模型用于广西沿岸海平面变化分析,结果表明北海、涸洲、白龙尾3站的相对海平面上升速率分别为1.67、2.51、0.89mm/a;石头埠相对海平面呈下降趋势,下降速率为0.5～1.0mm/a;广西沿岸绝对海平面上升速率为2.0mm/a.和线性趋势项与周期项叠加的海平面分析模型相比,两者模拟精度相当. 相似文献
17.
Morphodynamic modeling is employed in the present work to predict the long-term evolution (over the next 100 years) of typical sedimentary coasts in the western Russian Arctic. The studied objects are the coasts of Varandey (the Barents Sea), Baydaratskaya Bay and Harasavey (the Kara Sea). The model developed takes into account both the short-term processes (storm events) and long-term factors (for example, changes in sea level, inter-annual variations in gross sediment flux, lack or excess of sediment supply). Predicted and observed morphological changes in coastal profiles are shown to agree well for time scales ranging from weeks to decades. It is revealed that under given environmental conditions, the morphological evolution is strongly influenced by storm surges and associated wind-driven circulation. The water level gradient created by a surge generates a seaward flow at the bed. This outflow is shown to be an important destructive mechanism contributing to the erosion and recession of Arctic coasts. The rate of change is found to depend on both the exposure of the coast (relative to the direction of dominant winds) and its height above the sea. The open coast of Varandey is expected to retreat as much as 300–500 m over 100 years, while recession of the less exposed coasts of Baydaratskaya Bay would not exceed about 100 m/century. If long-term sediment losses are insignificant, the rate of erosion decays with time and the morphodynamic system may tend toward equilibrium. It is concluded that the expected relative sea-level rise (up to 1 m over the nearest 100 years) is non-crucial to the future coastal evolution if an erosion activity is already high enough. 相似文献
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A~as~Sof~~LIngeneral,sealevelisresolvedintOatrendtermplusaPeriedictermintheanalysisofsealevelvdriations(haetal.1996;ZuoandChen,1996;QinandLi,1997;Zhengetal.,1993;RenandZhang,1993),namely,thetimeequencesofmonthlyorannualmeansealevely(o)(t)canbeexpr~asy(o)(t)=T(o)(t) p(o)(t) X(o)(t) .(o)(t),(l)whereT(o)(t)isadefinitetrendterm;p(o)(t)isadefiniteperiedicterm;X(o)(t)isatimeseriesofrandomterm;a(o)(t)iswhitenoise.Thefunctionstructuresofthetrendtermaregenerallyunknown,whiledeterminingthetrendter… 相似文献
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Sediment supply and pre-existing shoreline morphology are crucial factors in controlling coastal changes due to sea-level rise. Using examples from both southeast and northeast Ireland, it can be shown that sea-level change may trigger a sequence of events which leads to both static and dynamic shoreline equilibrium. Cliff erosion and longshore sediment movement in east Co. Wexford has led to injection of sediment onto the shelf, and the growth, under both wave and tide regimes, of linear offshore shoals. These shoals now control the pattern of shoreline erosion and provide a template for possible stepwise evolution of the coast under any future sea-level rise. In contrast, the nearby coast of south Co. Wexford comprises a series of coarse clastic barriers moving monotonously onshore, via overwash processes. Here the behavior of the barrier is conditioned by the antecedent morphology of both the beach face and stream outlet bedforms. Finally, the rock platform coast of Co. Antrim presents a far more resistant shoreline to incident marine processes, yet even here there is strong evidence of present process control over so-called ‘raised’ platforms and embayments. It is concluded that coastal sediment supply and dynamics, together with coastal morphology and its interaction with waves, present a far more complex variety of sea-level indicators than is normally acknowledged. 相似文献