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1.
基于RS和GIS技术,利用多期遥感影像数据,结合地形图、历史海图,定量分析了辽宁省海岸线近百年变迁特征.结果表明,自1909年以来,辽宁省海岸线的构型和长度发生了很大变化,陆地面积也相应增加.在全省范围内,从时序变化看,1909~1932年期间,海岸线变化最大,陆地面积增加最多,年增加速率也较快,1950~1980年期间,海岸线变化速率最小.从空间上看,各地段的岸线变化极不均衡,主要变化区域是辽东湾北部淤泥质海岸,大连附近的基岩岸段变化最小,最大的变化区段是双台子河段、复州湾和大洋河附近. 相似文献
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天津市潮间带表层沉积物的类型及其分布 总被引：4，自引：2，他引：2
根据在天津市潮间带地区采集的108个底质样品的粒度分析结果,划分了潮间带表层沉积物的类型,并探讨了潮间带的粒度分布特征和沉积作用。结果表明,天津潮间带可分为3个岩性区,分别以海河口、独流减河口为界,海河口以北至涧河口为片状粘土质粉砂分布区,海河口以南至独流减河口为多岩性、条带状的砂-粉砂分布区,独流减河口至歧口为片状粘土质粉砂分布区。海河口以北的潮间带是以低能潮汐作用为主的泥质粉砂潮滩沉积环境,海河口以南的潮间带是以河口沉积为主体,后经潮汐改造的潮滩环境,驴驹河-独流减河河口岸段潮间带早期水动力较强,后受到潮滩环境的改造,歧口岸段潮间带以潮滩沉积环境为主。 相似文献
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全新世长江泥沙堆积的时空分布及通量估算 总被引：1，自引：1，他引：0
利用长江中下游、河口及口外、浙-闽沿岸陆架6个主要沉积盆地的40个晚第四纪钻孔及其年代学数据和长江口外、陆架的浅地层剖面,计算了全新世不同阶段各沉积盆地的沉积速率,并进行了近7 000年来泥沙堆积通量的估算。研究发现全新世早期距今10 000年至8 000年间长江口下切古河谷是长江泥沙的主要堆积中心,沉积速率可高达15m/ka。随着海平面上升,全新世中期长江中下游也成为长江泥沙的重要沉积盆地,其中江汉盆地的沉积速率可达10m/ka。近2 000年来,口外、陆架的堆积呈明显增加趋势,反映长江中下游盆地和河口可容空间日益减小。根据沉积速率估算,距今7 000年来长江中下游堆积泥沙约13 074×108 t,同期水下三角洲和陆架的泥沙堆积量约为9 470×108 t。研究还发现全新世以来有两个异常低沉积速率时期：距今8000-7 000年期间上述各沉积盆地沉积速率均显著低,未见长江泥沙的沉积中心; 距今4 000-2 000 年期间长江口呈现低沉积速率。 这两次异常的原因推测与海平面、气候波动事件密切相关。 相似文献
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福建省海岸线变迁及对城市建设的影响 总被引：2，自引：0，他引：2
本文以福建省海岸线地质地貌特征为依据,划分了:基岩海岸、砂质海岸和淤泥海岸三大海岸类型,又根据海岸变化的特点划分了。蚀退岸、淤涨岸和稳定岸,并详细地论述了它们的主要特征。作者研究了福建省第四纪以来气候交化及新构造运动引起的福建海面颊繁变化和海岸线变迁情况,认为全新世以来虽是一次海侵,但存在多次海面波动和海岸线变迁的过程,而不是直线式上升,在某些河口地区仍属海面上升,即基准面上升,使河流坡降变缓,搬运能力减弱,从上游携带来的大量泥沙,在河口堆积,其速度大于海面上升的速度。第四纪以来海面变化,海岸线变迁形成的地质地貌特征,对沿海港口城市建设、工农业生产,人民生活、水产、航运等都会产生,并将继续产生不可忽视的影响。因此在建设沿海城市、港口和经济开发区规划时,必须加强海岸线变迁的研究,进一步掌握海岸线变迁规律,为国民经济建设服务。 相似文献
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为研究近期荆江段崩岸过程及特点,利用实测水下地形图及固定断面资料,分析了三峡工程运用前后该河段平面及断面的形态变化过程。平面形态对比结果表明:2002-2013年荆江段多年平均崩退速率约为15.0 m/a,崩岸总长达42.3 km,左岸占59.2%;下荆江岸线崩长约为上荆江的2.2倍,且石首、调关及荆江门等河湾凸岸一侧受低含沙水流长期冲刷不断崩退,其岸线崩长约占下荆江崩岸总长的35.5%。断面形态对比结果显示:2002-2015年荆江段约有21%断面存在明显的崩岸现象,且近74%的崩岸断面位于下荆江。故近期荆江段崩岸分布规律主要表现为左岸多于右岸,下荆江多于上荆江,且下荆江部分河湾凸岸崩退显著。定量分析了河岸土体组成与分布、来水来沙条件等因素对崩岸过程的影响,发现来水来沙条件的影响占主导地位。建立了上、下荆江典型断面平滩河宽与前期水沙条件之间的经验关系,除工程守护良好的断面外,相关系数均高于0.85,提出的经验公式可较好反映水沙条件变化对平滩河宽调整的影响。 相似文献
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黑龙江由于受水流、冰凌，风浪冲刷及人类活动的影响，造成了河道坍岸、片坡、滚动和改道。其后果是很严重的。危及河道稳定，主航道改造，大片国土流失，很多岛屿另归俄方，人民财产和生命受到威胁等。据已有资料统计：兴东至松花江入口江段的江岸每年坍塌5～10m。再下至伯力段，每年平均塌岸8～20m，长度为110km。其中有5道弃滩改道，及二村童喇叭岛、头道河至街津口段、额图至勒得利段，王家店后河至醉江河口段和三叉岛至抚远镇段，以上涉及岛屿面积数100km^2。国土流失程度令人触目惊心。 相似文献
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认识崇明东滩岸线的演变规律,对于崇明东滩湿地的保护和利用具有重要意义。利用面向对象的方法,选取1987年至2006年中的6景Landsat-5 TM卫星影像数据,解译出对应年份的东滩岸线。为了对较复杂的非平直岸线的变化进行建模,提出了基于地形梯度的正交断面方法,构建了基于图形学的分析预测模型,对岸线的演变进行分析,预测了2010年和2015年的岸线位置。结果显示：（1）崇明东滩以东南角节点为界,分为南侧的侵蚀岸段和其余的淤涨岸段,总体淤涨速率有减慢趋势,最大侵蚀速率为22.0 m/a,最大淤涨速率为247.2 m/a;（2）北侧自东旺沙水闸向东约4 km长的岸段存在明显的冲淤交替现象;（3）岸线演变受抑制区段都位于东滩两侧岛影缓流区的边界;（4）由于岸外东南侧发育有10 m深槽,除非有特殊的水动力条件出现,东滩未来的岸线将偏向东北方向演变。 相似文献
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北塘凹陷古近系沙河街组三段物源体系分析 总被引：6，自引：0，他引：6
物源分析是盆地分析的重要内容之一.北塘凹陷古近系沙河街组三段(Es3) 湖泊范围广、沉积厚度大, 而勘探程度低, 是大港油田未来勘探的重要突破区, 精细刻画北塘凹陷沙三段物源体系对沉积体系重建、有利区带预测具有重要意义.采用构造格架及古地貌宏观区分物源区与沉积区, 根据碎屑矿物组合特征划分物源区块, 依据地震反射特征勾绘物源在盆内进积方向, 利用砂体等厚图和砂地比等值线图精细描绘物源分支, 从不同角度、不同层次对北塘凹陷沙三段古物源体系进行精细研究.结果表明, 北塘凹陷物源来自北部燕山褶皱带和西部沧县隆起, 具体分为西部的沧县物源、西北角的汉沽物源、北部的大神堂物源和东北角的涧南物源.在物源体系和构造组合特征的控制下, 沙三段主要发育扇三角洲沉积体系. 相似文献
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基于遥感与GIS技术,利用高空间分辨率遥感卫星SPOT-5和GF-2影像数据,对海南岛西北部地区海口市南渡江—东方市2005年和2016年2个时期的海岸线进行人机交互解译,并对其10 a来的时空变化特征进行了分析。结果表明: 10 a间,海南岛西北部海岸线时空变化显著,主要影响因素为人工开发建设; 人工海岸线增幅达到113%,其占比由2005年的24.3%上升至2016年的51.6%; 除部分淤泥质海岸线和砂质海岸线转化为人工海岸线外,自然海岸线以侵蚀为主,局部地区有少量淤积。不同地区海岸线变化特点不同: 儋州市和澄迈县海岸线资源丰富,开发力度较大; 临高县和昌江黎族自治县自然海岸线以侵蚀为主,淤积少; 东方市和澄迈县海岸线侵蚀较少,较易淤积。分析结果可为海南岛西北部海岸线调查、开发和保护提供一定的科学依据。 相似文献
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Historical shoreline trend analysis and drivers of coastal change along the Ravenna coast,NE Adriatic 总被引：1，自引：0，他引：1
Oxana Sytnik Laura Del Río Nicolas Greggio Jarbas Bonetti 《Environmental Earth Sciences》2018,77(23):779
One of the most important aspects of coastal zone management is the analysis of shoreline dynamics. Over the last years, beaches of the Ravenna coast (NE Italy) experienced large modifications, in some places narrowing or even being completely lost, thus threatening tourism, coastal assets and nature. Coastal erosion has direct consequences for Ravenna tourist-based economy, which largely depends on the attraction provided by sandy beaches. In this study, long-term (>?50 years) coastal analysis was used to identify the sectors along the coast where the shoreline position has changed, either advancing or retreating. Shoreline changes were measured on GIS environment by means of Digital Shoreline Analysis System (DSAS) extension. Net Shoreline Movement (NSM) and Linear Regression Rate (LRR) strategies were employed to examine shoreline variability and reveal erosional/accretional trends. The results show that significant shoreline changes affected the entire coastal region, with most of the study area under retreat, mainly in the most valuable tourist assets of the littoral. The effects were found to be worsened by impacts of land subsidence, presence of harbor infrastructure and deficit in sediment budget. A simple shoreline classification was performed over the DSAS results and cross-checked with local knowledge of the area. The measurement of erosion or accretion rates in each studied segment is found to be useful for land use planning and coastal management plans, especially regarding the prediction of future shoreline positions. Especially important is the potential of the classification to identify areas of significant position change, with current and future implications for the design of sustainable shoreline management and mitigation measures. 相似文献
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Previous studies on the deglaciation of the Appalachians of southern Québec reconstructed only the most extensive ice-dammed lakes and the most stable glaciolacustrine water levels. They only used the best developed shoreline features, and thus were not able to reconstruct small or short-lived ice-dammed lakes, both being characterized by a weak development of their features. We propose a methodology to reconstruct glacial lakes which follows three main steps: (1) the mapping of shoreline features, generally the best developed ones, as in previous studies; (2) the delineation of the former shoreline for each water level, by also considering the less well-developed shoreline features which were found during field surveys designed as a function of the presumed shoreline position; and (3) the mapping of the maximum extension of the water plane, which includes the location of the former ice dam and of the former glacial lake spillway. In southern Québec, small ice-dammed lakes were numerous and important because they shaped the geomorphology of the region during the deglaciation. They are thus among the key components of a deglaciation model for this area. 相似文献
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海岸带是陆地向海洋延伸的过渡地带,是人口最为密集、人类活动最频繁的区域,全球超过50%的人口和60%的GDP总量集聚在离海岸线不足100 km的区域。海岸线对海平面上升、海岸侵蚀、港湾淤积、湿地生态资源、近海海域环境等具有重要的指示作用。本研究利用遥感影像获取了粤港澳大湾区（以下简称大湾区）1975—2018年间的大陆海岸线数据,并基于GIS平台,对海岸线开发利用程度以及空间位置变迁进行了定量分析,探讨了海岸线变迁的驱动力。结果表明：（1）大湾区大陆岸线时空变化明显,总体可分为两个阶段。1975—1995年,岸线长度上升明显,岸线类型格局变化显著;1995年后,岸线长度增长较缓,但建设用地态势增长强劲。（2）大湾区大陆岸线整体形态上不断曲折化,分形维数逐渐增长;空间位置变化上,大陆岸线不断向海推进,年平均速率达9.91 m/a,向海延伸最远的地方出现在洪奇门至蕉门和虎跳门至鸡啼门岸段附近,最大值可达197.88 m/a。（3）大湾区大陆岸线的开发利用程度及人类活动干预程度处于逐渐增强的趋势,人为影响主要体现为港口码头建筑岸线及围填养殖岸线。（4）大湾区的地形地貌、水文特征等自然环境是岸线演变的基础,社会经济发展和政策是岸线演变的重要驱动因素。在20世纪末,发展速度对海岸线的影响最大;在21世纪初,发展强度则为演变的主要影响因素。 相似文献
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津冀海岸线现状、变化特征及保护建议 总被引：1，自引：0，他引：1
根据覆盖全区的3期遥感影像和实地调查,以及对滨海新区和滦河口2个典型区更深入的案例研究(包括回溯至1870年、1950年的基准岸线及逐年遥感信息),对津冀沿海海岸线现状进行解译和分类,并分析岸线变化特征及成因。津冀沿海现状岸线总长度894km,可以划分为自然岸线、半开发岸线和人工岸线3类,长度分别为90km、329km和475km。1950年以前为自然因素主导的岸线变化,1950年以后变为人类活动主导的岸线向海推进,逐渐加强的人类活动至2010年达到顶峰。在全球海面上升和区域地面下沉的大背景下,海岸线的自然演化趋势应该是向陆蚀退,但是人类活动主导的岸线变化却表现为违反自然趋势的向海推进。今后,向海推进最前沿的围海造陆区将受到来自海洋越来越强烈的影响,亟需加强监测和防护。兼顾环境保护与开发两方面的长远需求,建议赋予海岸线新的定义与内涵,划定岸线保护红线,恢复部分岸线的自然属性。 相似文献
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Monitoring shoreline change on Djerba Island using GIS and multi-temporal satellite data 总被引：1，自引：0，他引：1
In the absence of a generic approach to study shoreline changes, this research focus on the development of a generic methodology to detect, measure, analyze, and predict shoreline changes to manage coastal environment. The unique strength of this approach is that it incorporates image processing techniques, remotely sensed derived data into a GIS to analyze measure, and predict and visualize shoreline changes. It is independent from the study region or the remote sensing data. This methodology uses Speeded Up Robust Feature to detect the study regions from satellite images automatically. Also, it proposes a model of shoreline using the Canny edge detector on Normalized Difference Water Index image. To measure the changes, Digital Shoreline Analysis System extension of ArcGIS was used and the End Point Rate (EPR) and Linear Regression Rate (LRR) approaches were used on the modeled shoreline. The EPR is calculated by dividing the distance of shoreline movement by the time elapsed between the oldest and the most recent shoreline. A LRR statistic can be determined by fitting a least-squares regression line to all shoreline points for a particular transect. Three regions of the island of Djerba in Tunisia were selected for this study; Rass Errmall, El Kastil, and Aghir. Accretions as well as erosion processes were observed in the study areas between 1984 and 2009. The average of the erosion was around ?6.95 m/year in Aghir. The average of erosion is around ?4.09 m/year and accretion trend is around +11.7 m/year in Rass Errmall. El Kastil was under a remarkable accretion with 21.14 m/year during the same period. 相似文献
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Christopher J. Patrick Donald E. Weller Xuyong Li Micah Ryder 《Estuaries and Coasts》2014,37(6):1516-1531
Submerged aquatic vegetation (SAV) provides many important ecosystem functions, but SAV has been significantly reduced in many estuaries. We used spatial–statistical models to identify estuarine shoreline characteristics that explain variations in SAV abundance among subestuaries of the Chesapeake Bay and mid-Atlantic Coastal Bays. We summarized digital spatial data on shoreline construction, shoreline land use, physical characteristics, watershed land cover, and salinity for each subestuary. We related SAV abundance to shoreline characteristics and other stressors using univariate regression and multivariate models. The strongest univariate predictors of SAV abundance were percent shoreline forest, percent shoreline marsh, the percentage of shoreline that is 5–10 m tall, percent riprap, the percentage of subestuary area <2 m deep, percent herbaceous wetland, and percent shrubland. Shoreline marsh, bulkhead, and shoreline forest had different effects on SAV in different salinity zones. Percent riprap shoreline was the most important variable in a regression tree analysis of all the subestuaries, and percent deciduous forest in the watershed was the most important variable in a separate regression tree analysis on the mesohaline subestuaries. Subestuaries with <5.4 % riprap followed a significantly different temporal trajectory than those with >5.4 % riprap. SAV abundance has increased steadily since 1984 in subestuaries with <5.4 % riprap, but has not increased since 1996–1997 in subestuaries with >5.4 % riprap. Some shoreline characteristics interact with larger-scale factors like land cover and salinity zone to affect the distribution of SAV, while the effects of other shoreline characteristics are consistent among subestuaries with different salinities or local watershed land covers. Many shoreline characteristics can be controlled by management decisions, and our results help identify factors that managers should consider in efforts to increase SAV abundance. 相似文献
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Recent projections of global climate change necessitate improved methodologies that quantify shoreline variability. Updated analyses of shoreline movement provide important information that can aid and inform likely intervention policies. This paper uses the Analyzing Moving Boundaries Using R (AMBUR) technique to evaluate shoreline change trends over the time period 1856 to 2015. Special emphasis was placed on recent rates of change, during the 1994 to 2015 period of active storm conditions. Small segments, on the order of tens of kilometers, along two sandy barrier island regions on Florida’s Gulf and Atlantic coasts were chosen for this study. The overall average rate of change over the 159-year period along Little St. George Island was ??0.62?±?0.12 m/year, with approximately 65% of shoreline segments eroding and 35% advancing. During periods of storm clustering (1994–2015), retreat rates along portions of this Gulf coast barrier accelerated to ??5.49?±?1.4 m/year. Along the northern portion of Merritt Island on Florida’s Atlantic coast, the overall mean rate of change was 0.22?±?0.08 m/year, indicative of a shoreline in a state of relative dynamic equilibrium. In direct contrast with the Gulf coast shoreline segment, the majority of transects (65%) evaluated along the oceanfront of Merritt Island over the long term displayed a seaward advance. Results indicate that episodes of clustered storm activity with fairly quick return intervals generally produce dramatic morphological alteration of the coast and can delay natural beach recovery. Additionally, the data show that tidal inlet dynamics, shoreline orientation, along with engineering projects, act over a variety of spatial and temporal scales to influence shoreline evolution. Further, the trends of shoreline movement observed in this study indicate that nearshore bathymetry—the presence of shoals—wields some influence on the behavior of local segments of the shoreline. 相似文献
19.
Robert Metz 《Central European Journal of Geosciences》2012,4(1):3-8
Mudstones of the Triassic Passaic Formation, near Milford, New Jersey, have yielded the first evidence of an arthropod impression in that formation. Associated trace fossils include Helminthoidichnites, Lockeia, Scoyenia, Spongeliomorpha, and the reptile footprint Rhynchosauroides, representing the Scoyenia ichnofacies. Associated sedimentary structures include desiccation cracks and raindrop impressions. The Passaic sediments were deposited under shallow water lacustrine shoreline conditions subject to periodic subaerial exposure. 相似文献
20.
Aerial photographs, recording 12 positions of the shoreline and vegetation line over a 50-yr period, were used to investigate
long-term ecotone displacement trends and the relationship between ecotone displacement and shoreline migration on Hog Island,
Virginia. A robust regression modeling technique, originally developed for shoreline trend detection analyses, enabled examination
of the direction, magnitude, and timing of changes in long-term ecotone displacement. Measurements were obtained at 277 shore
normal transects spaced 50 m apart. The results show that long-term trends in ecotone displacement and shoreline movement
are nonlinear for over three-fourths of the Hog Island coast. On average, the shoreline and vegetation line experienced reversals
in 1972 and 1974, respectively. Rarely did the ecotones and shorelines move in tandem or synchronously. Concavity tests indicate
that most of the shoreline and ecotone are currently moving seaward and the distance between the shoreline and vegetation
line is decreasing through time. Evidence exists for a decennial time lag between the reversal of the shoreline and the ecotone
and vice versa. The ecotone and shoreline trends apparently correspond to tidal inlet dynamics, individual storm events, storm
climate, inherited topography (e.g., dune), and vegetation type. 相似文献