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1.
玉带沙是海南岛东部博鳌万泉河口的一条细长沙嘴,也是我国重要旅游海滩之一。为了揭示近期玉带沙的冲淤演变趋势,选择了1988年以来4个年份的RS图像,利用现场GPS监测的海滩地形推算出校正后的低潮位水边线,并使用GIS软件计算各年份低潮线以上的玉带沙面积。结果表明：1988～2005年玉带沙呈显著蚀退趋势,平均蚀退70m（4.1m/a）,面积减少35%。分析认为：玉带沙蚀退主要原因是海平面上升和万泉河入海泥沙的减少。在气候变化与人类活动的双重作用下,玉带沙呈现高度脆弱性,值得关注。 相似文献
2.
河北省沙质岸滩存在海岸侵蚀现象,对沙滩旅游、海滩工程建设造成严重威胁,制约河北省海洋经济社会发展。海岸侵蚀监测结果显示,区域海滩滩面受波浪、潮流影响较大,时冲时淤,摆动频繁,沙质岸滩整体处于侵蚀状态,各区段蚀淤情况有所差异,高潮线以上有所淤高,海滩坡度开始变陡,呈下蚀状态。海岸侵蚀灾害已引起沙滩沙质粗化、滩肩变窄、滩坡变陡及基岩裸露比率增多等问题。针对这一突出问题,通过定点测量与遥感监测相结合的方式,研究了河北省海岸线动态演变特征,经计算,河北省各侵蚀岸段海岸侵蚀速率达1.0~4.0m/a,单宽体积侵蚀量-1.42~-19.08m~3/m·a。综合分析显示,人类海岸工程建设、区域海洋水文条件及输砂量减少,是河北省发生海岸侵蚀发生的主要原因。 相似文献
3.
海岸现代风成砂粒度参数特征的研究--以中国温带海岸为例 总被引：6，自引：1，他引：6
现代海岸风成砂的粒度特征是海岸风沙研究的重要问题,本文以我国温带海岸为研究区域,利用 136个现代海岸风成砂样数据,通过粒度组成、平均粒径、标准偏差和偏差、峰态等粒度参数分析了其粒度特征。结果表明,我国温带海岸的现代风成砂并非过去认为的几乎全由分选很好的细砂组成,是以正偏为主,粒度参数的地域差异明显,并随沙丘类型、规模及距海岸线的远近不同等而变化。与海滩砂比较,风成砂具有普遍含有粉沙、略细、多正偏、峰态偏窄等特点,但利用粒度参数散点图和因子分析法二者均无法区分。我国温带海岸现代海岸风成砂粒度参数的上述特征与其特有的发育条件和演化过程密切相关,其中主要与季风气候特征显著、形成时间短、风力作用时间有限以及风沙活动空间狭小并受到水力与重力作用的干扰等有关。 相似文献
4.
A. Di Matteo M. Milli Ph.D. 《International Journal of Environmental Science and Technology》2008,5(3):415-424
This paper outlines the results of a study recently carried out on the western coast of the Sestri Levante peninsula (Eastern Liguria-Italy), aiming to assess the effects of newly accomplished defensive measures against coastal erosion: the accretion of the beach with natural sand and its protection with artificial structures orthogonal and parallel to the shoreline. Through conventional and more innovative methodologies (respectively single beam echo sounders and global positioning system) the research work has resulted in a new evaluation of the morphological, bathymetric and sedimentological features that make up this shoreline and its volumetrical change over the century. The survey and the research carried out on the studied area have enabled us to give a more detailed picture of the evolution of the littoral, to assess the possible use of “non-traditional” techniques of beach development monitoring, to evaluate the volumetric variations of the emerged and submerged beaches, to establish the sedimentological activity of the beach after the latest nourishment measures, and finally, to verify the effectiveness of the protection measures implemented on this coastline. The acquired data have been stored in the database and a geographic information system has been used to process, analyze, and evaluate the results. The main findings show that the latest intervention has brought about a new phase in the evolution of the coastline, giving rise to a new pseudo-balanced condition. The re-distribution of materials used for the beach nourishment, leads us to believe that the defence underwater barrier has only partially worked. The main conclusion for a correct coastal zone management underline the necessity to plan local and more wide monitoring during at least 8–10 consecutive years. 相似文献
5.
探地雷达(GPR)在海南岛东北部海岸带调查中的应用 * 总被引：2，自引：0，他引：2
对海南岛东北部海岸带调查采用了探地雷达(GPR)研究海岸带沙体的结构、展布和沉积序列,取得了很好的效果。文章通过和有限的露头资料对比以及对反射波形态、结构的研究,确定了海滩脊、海岸沙丘的反射特征以及潜水面的位置。雷达图像显示五龙港古海滩脊由亚水平、不连续、高振幅和透镜状反射波组成;木兰头海岸沙丘已受到人类活动的扰动,短的、陡倾斜反射可能代表未受扰动的海岸风成沙的前积层。研究表明探地雷达是一种可靠、快速和经济的地球物理方法,在砂砾质海岸可产生高质量、高分辨率和连续的反射剖面,值得加以推广。 相似文献
6.
Numerical modeling of the effects of beach slope on water-table fluctuation in the unconfined aquifer of Donghai Island,China 总被引：2，自引：0，他引：2
Beach slope is an important factor influencing the tide-induced water-table fluctuation in coastal unconfined aquifers. However, research about the effect of beach slope on water-table fluctuation is limited, especially for gentle slopes. To understand the effect of beach slope on beach groundwater dynamics, a numerical model, calibrated with field monitoring data from Donghai Island (China), was built to simulate the observed water-table fluctuation. Sensitivity analysis was performed to assess the sensitivity of water-table fluctuation to the parameters and conceptualization of the model. The analysis indicated that the water-table fluctuation was especially sensitive to the hydraulic conductivity and specific yield, and the horizontal length of the model domain could affect the amplitude of the water-table fluctuation. Moreover, it is found that the variation of the amplitude is more evident when the beach-slope angle changes in the range from 1.5 to 45°, especially in the range from 1.5 to 5°. Understanding the effect of beach slope on tide-induced water-table dynamics could help modelers deal with the slope better in their beach groundwater flow models. 相似文献
7.
全面准确评估海滩的时空演变,是海滩侵蚀防护的前提;基于卫星图像资源全面准确评估海滩的时空演变,对于缺乏长期连续实测数据的海滩的侵蚀防护具有重要意义。本研究基于谷歌地球引擎合成并下载灵南海滩(灵山湾南部海滩)1984—2021年的880幅卫星图像,聚焦海滩剖面提取干湿线和水边线在剖面上的位置;结合模拟潮位分析海滩剖面形态,计算海滩坡度和平均高、低潮线等,采用多指标研究灵南海滩的时空演变;结合历史资料分析影响灵南海滩演变的主要因素,并利用海滩实测数据评估利用卫星图像提取的海滩岸线的误差。结果表明,大量卫星图像的应用提高了研究结果的时间分辨率、精度和可靠性。在1984—2021年间,灵南海滩部分岸段发生了阶段性快速侵蚀,侵蚀速率为5.2~60 m/a,总侵蚀量达30~78 m,持续时间为0.5~11年,该快速侵蚀主要是挖沙、养殖场改建和废弃等人为因素造成的,风暴潮起次要的辅助作用。除上述快速侵蚀时段外,灵南海滩普遍发生慢速侵蚀,侵蚀速率一般小于2 m/a,这是相对海平面上升和河流入海泥沙锐减等的结果。 相似文献
8.
对海滩地下结构的认识是海岸带研究的一个重要方面,也是海滩保护和开发的基础。目前对于海滩的研究大多集中在表面动态变化监测和研究,而对于海滩内部结构和基底形态研究还非常有限。现有的钻探和探测手段一般只能研究表层砂体,难以探测到砂体的底部,无法建立海滩的整体结构模型,不利于分析砂的储量和研究海滩的演化。因此,需要一种探测手段,以便快速有效地开展砂体结构的大范围探测。本文把多尺度地震层析成像方法应用于海滩结构研究,以山东半岛东南部花岗岩石质海岸的一个典型海滩—青岛石老人海水浴场为例,对石老人海滩下方从地表到结晶基底的整体结构开展研究。通过采用新研制的重锤震源得到较高信噪比的地震数据,使用多尺度地震层析成像方法对海滩地下结构进行建模,建立了青岛石老人海水浴场海滩下方深达50 m的速度结构模型。所建立的速度结构模型与该区域已有的对砂体厚度的认识,以及海滩钻孔取样得到的柱状样品的砂粒度变化曲线吻合。该速度结构模型显示,测线下方砂体北厚南薄,在后滨的厚度约为15 m,而在前滨仅有5 m左右。我们推测,海滩下方的砂体中可能存在直立的岩石和未风化完全的岩石,海滩下方的不均匀风化作用导致其下方基底呈现下凹的形态,这种基底形态可能具有稳定砂体的作用。本文方法能够快速有效地构建海滩下方速度结构模型,并且可以方便地推广到其他海滩的结构探测,对于研究海滩结构、演化过程和沙滩保护具有重要意义。 相似文献
9.
Nico Valentini Alessandra Saponieri Matteo Gianluca Molfetta Leonardo Damiani 《Earth Science Informatics》2017,10(4):495-506
Video systems have become widely used all around the world in coastal monitoring strategies, allowing both high temporal and spatial sampling frequency, with low logistic and costs efforts. The present paper deals with a new tool for coastal images processing, aimed at the automatic shoreline detection and data analysis. The tool is composed by a shoreline detection routine implemented in a web-application, addressed at images processing (i.e. shoreline extraction and geo-rectification), data analysis and sharing results about beach actual state and shore evolution in quasi-real time. The Shoreline Detection Model (SDM) is based on a new algorithm, implementing image-processing procedures, which allows extracting the sea/land boundary from automatic segmented Timex images. The SDM calibration and validation has been performed on different coastal images derived from a video monitoring system installed at Alimini (Lecce, IT) in 2005, by comparing automatic shoreline contours with the manual detected ones. Moreover, in December 2015, new video monitoring systems were installed in South Italy (Porto Cesareo and Torre Canne, Apulia region), at sandy beaches affected by erosion phenomena. The application of the SDM on images recorded by the new systems has allowed testing the model feasibility at sites characterized by different morphological features and geographical exposition. The present describes in detail the SDM algorithm and the image processing procedures used. The results of the model calibration and validation performed at Alimini and the tests performed at Porto Cesareo on first images are reported. 相似文献
10.
美国海岸带自然资源与生态损害评估及修复工作对中国的启示 总被引：1，自引：0，他引：1
海岸带是位于海陆结合部的复杂环境系统,是人类活动最集中的地区。中国大陆海岸线约18000km,涉及沿海11个省,由于经济社会高速发展,海岸带地区的人口、资源、环境矛盾日益突出,面临海岸带资源无序开发、水土污染、滨海湿地退化、海岸侵蚀、地面沉降等一系列生态环境与灾害地质问题,已成为影响生态文明建设的主要问题之一。因此中国持续加大海岸带生态环境保护力度,并提出实施重要生态系统保护和修复重大工程、强化湿地保护和修复等政策措施。美国国家海洋和大气管理局主导的海岸带损害评估及修复计划已实施了近30年,并取得了显著效果,其完善的法律制度体系、规范的损害评估和修复程序、数据集成管理和共享应用等成功经验值得学习借鉴。建议加快完善中国海岸带生态环境损害评估与修复的技术方法体系和制度体系、有序开展海岸带自然资源和生态环境调查、加强海岸带及滨海湿地等重要生态系统的演化和修复技术研究与示范,并构建统一的海岸带基础调查数据库、建立海岸带监测预警体系。 相似文献
11.
A. Merlotto G. R. Bértola F. I. Isla L. C. Cortizo M. C. Piccolo 《Environmental Earth Sciences》2014,71(3):1213-1225
The short and medium-term coastal evolution of Necochea Municipality, Buenos Aires province (Argentina) was studied. The medium-term evolution study was based on aerial photographs from 1967 and 1984, and satellite images from 2004, using the dune or cliff toe as coastline indicator. The short-term evolution was studied from February 2006 to December 2009 by means of seasonal beach profiles and sediment sampling. Results showed that in the medium-term at Necochea, the coastline has remained stable or has advanced. Whereas in the short-term, the analysis has evidenced incipient erosion processes. On the other hand, at Quequén the retreat of the coastline and the negative sedimentary balances (medium and short-term) are clearly indicating an accentuated erosion process. The different degrees of coastal erosion are related in part to beach vulnerability to wave storms but mainly to anthropogenic actions, which have affected the beach sediment supply. These results evidence the necessity to develop a coastal management programme. 相似文献
12.
Barendra Purkait 《Frontiers of Earth Science》2009,3(1):21-33
Coastal erosion at Sagar Island of Sunderban delta, India, has been critically studied. The area is in the subtropical humid
region. There are mainly three seasons viz: winter, summer and the monsoon. Different wave dynamic parameters were measured
from theodolite observations with leveling staff and measuring gauges during lunar days at two sections of the western and
eastern parts of the coastal zone during post-and pre-monsoons. A comparative study was made on the erosion/depositional pattern
between the two sections in relation to different hydrodynamic parameters prevailing in these two sections. Plane table mapping
was carried out to demarcate the different geomorphic units. The marine coastal landforms show dune ridges with intervening
flats bordered by gently sloping beach on one side and a flat beach on the other side. The western part of the beach is mainly
sandy; whereas the eastern part is silty and clayey with mud bank remnants. Actual field measurements indicate that the coastal
dune belt has retreated to the order by about 20 m since 1985. The eastern part of the beach has lowered by about 2 m since
1985 and the western part was raised almost to the same tune. It is observed that accretion in the western and central parts
of the beach took place; whereas severe erosion in the eastern part made the beach very narrow with remnants of mud banks
and tree roots. Frequent embankment failures, submergence and flooding, beach erosion and siltation at jetties and navigational
channels, cyclones and storm surges made this area increasingly vulnerable. 相似文献
13.
Electrical resistivity tomography mapping of beachrocks: application to the island of Thassos (N. Greece) 总被引：1，自引：0，他引：1
Psomiadis David Tsourlos Panagiotis Albanakis Konstantinos 《Environmental Earth Sciences》2009,59(1):233-240
Electrical resistivity tomography (ERT) technique is widely used in mapping subsurface electrical properties. In this study,
ERT was used to map a beachrock outcrop, extended both inland, under beach sediments, and seawards, on and under seafloor
sediments. Mapping of beachrock is considered important because it can help evaluate the lateral and vertical extend of the
formation. Fast and reliable mapping of beachrocks may contribute in several applications like engineering and construction,
coastal management, recreational reformation as well as scientific approaches like coastal evolution research, and palaeo-environmental
studies. The outcome of the survey was the mapping of the formation with centimeter precision, especially towards the sea.
Special processing was applied to the data in order to constrain the inversion procedure to include the known sea water layer. 相似文献
14.
As a type of negative topography in sand land, blowout has always been one of the main research object of aeolian geomorphology. Especially, multi-directions and long-term research has been conducted internationally on basic morphology, development process and dynamic mechanism of coastal sandy blowout. Based on the systematic review of research on coastal sandy blowout, the main progress of research on coastal sandy blowout in morphological evolution, morpho-dynamic process, and research methods was summarized. In consideration of the disadvantages of research on coastal sandy blowout, it was proposed that, at present, the research on coastal sandy blowout in China should strengthen the further research on the evolution mechanism, morphology-material-dynamic process and numerical simulation of different types of blowouts, and attach importance to the influence of blowout on the beach-dune dynamic environment and foredune restoration. 相似文献
15.
歧北斜坡区沙一下亚段湖相碳酸盐岩储层较薄（多数集中在0.5~8 m）,地震资料难以指导内部小层及滩体划分,沉积相模式、演化规律及主控因素认识不清,采用标志层控制、静-动态资料相互拟合的方法,利用岩心、测井、地球化学、古生物等资料,结合示踪剂、吸水剖面等动态资料对薄层湖相碳酸盐岩储层进行综合研究。研究结果表明：超覆地层对比模式符合研究区薄层湖相碳酸盐岩地层真实发育情况,并识别出5期明显的湖岸线;湖水首先沿着港西断层形成的断槽及中部的斜坡低洼区由东向西主发生湖侵;研究区主要发育滨浅湖亚相,包括生屑滩、混积滩等6种沉积微相,生屑滩面积占60%以上;沉积模式显示出沉积早期,地形坡度大、湖侵范围小、滨浅湖面积也最小,主要沉积沿岸碎屑岩砂坝;沉积中后期,水体越过坡折带,滨浅湖面积不断扩大,并迅速超覆至全区,生屑滩沉积面积达到最大的演化规律。歧北斜坡区湖水咸化、湖相碳酸盐岩广泛沉积的主要原因,是海侵作用致使湖水初步咸化和浅水缓坡台地环境导致混合水蒸发浓缩二次咸化双重作用的结果。强烈的剥蚀和填平补齐导致的近似平台型古地貌特征和古生物的大量繁殖,也是控制北斜坡区沉积相类型及演化的主要因素之一。 相似文献
16.
通过多期遥感资料,在潮水位基本相同的前提下,对江苏沿海中段低潮滩的时空演变从三个方面进行了分析,进一步指出其演变趋势已由淤转蚀,并已威胁到中潮滩,滩涂资源呈逐年减少的趋势;强调海涂资源并非是取之不尽用之不竭,唤醒人们要更加珍惜和使用好每一寸自然资源的意识。 相似文献
17.
Gianluigi Di Paola Pietro Patrizio Ciro Aucelli Guido Benassai Germán Rodríguez 《Natural Hazards》2014,71(3):1795-1819
This paper presents a new method for coastal vulnerability assessment (CVA), which relies upon three indicators: run-up distance (as a measurement of coastal inundation), beach retreat (as a measurement of potential erosion), and beach erosion rate (obtained through the shoreline positions in different periods). The coastal vulnerability analysis of Sele Coastal Plain to storm impacts is examined along a number of beach profiles realized between 2008 and 2009. This particular study area has been selected due to its low-lying topography and high erosion propensity. Results are given in terms of an impact index, performed by combining the response due to coastal inundation, storm erosion, and beach erosion rate. This analysis is implemented on the basis of morphosedimentary characteristics of the beach, wave climate evaluation, and examination of multitemporal aerial photographs and topographic maps. The analysis of the final results evidences different coastal responses as a function of the beach width and slope, which in turn depend on the local anthropization level. The comparison of this method with a Coastal Vulnerability Index method evidences the better attitude of CVA index to take into account the different beach features to explain the experienced damages in specific stretches of the coastline considered. 相似文献
18.
针对目前对大陆架砂成因问题的争议,本文从海陆过渡带动力关联的统一的环境体系,选取环境相关的海岸与大陆架砂质沉积做对比分析,获知东海大陆架砂的沉积特征和形成环境不具备高度的均一性,因而不是统一的大规模风成堆积,它们基本上均属于河口海岸-浅海环境下的产物。据大陆架砂的沉积特征以及当代关于沙漠化概念的内涵,质疑东海大陆架"沙漠化"的观点。 相似文献
19.
青海湖是我国最大的内陆湖盆,对气候变化十分敏感,而滩坝是青海湖滨浅湖带最为发育的沉积类型之一,其滩坝分布规律对晚更新世以来的古气候演化具有重要指示意义。在对青海湖一郎剑剖面进行实地考察的基础之上,对滩坝的分布规律及沉积特征进行精细解剖。通过分析总结前人相关测年数据,并与青海湖滩坝分布规律进行对比,发现青海湖湖平面升降对滩坝分布有明显的控制作用,建立了18 ka以来青海湖滩坝的演化过程,并将近18 ka以来青海湖湖平面升降史分为4个阶段:(1)更新世末温湿期,湖平面在海拔3 197～3 202 m附近波动;(2)全新世冷干期,湖平面近乎干涸;(3)全新世大暖期,湖平面处于全新世以来的最高值,约为3 212 m;(4)全新世凉湿期,湖平面回落到3 200 m附近,并在近2. 5 ka湖平面加速下降。在晚更新世和晚全新世时,湖平面在海拔3 202 m附近波动时间较长,在该海拔范围内,形成了规模较大的复合滩坝;在早全新世,青海湖平面最低,多发育风成黄土和潟湖沉积;在中全新世,湖平面最高,形成了距离现今湖平面最远的数列单体滩坝。 相似文献