Mapping bathymetry based on waterlines observed from low altitude Helikite remote sensing platform     

JO Young-Heon  SHA Jin  KWON Jae-Il  JUN Kicheon  PARK Jinku 《海洋学报(英文版)》2015,34(9):110-116

Mapping shoreline changes along coastal regions is critically important in monitoring continuously rising sea surface heights due to climate change and frequent severe storms. Thus, it is especially important if the region has very high tidal ranges over very gentle tidal flats, which is a very vulnerable region. Although the various remote sensing platforms can be used to map shoreline changes, the spatial and temporal resolutions are not enough to obtain it for a short time. Accordingly, in this study we introduce the newly developed low altitude Helikite remote sensing platform to achieve much better resolutions of shorelines and a bathymetry. The Helikite stands for Helium balloon and Kite, which is a kind of aerial platform that uses the advantages of both a Helium balloon and a kite. Field experiments were conducted in the Jaebu Island, off the coast of the west Korean Peninsula in January 29, 2011. In order to extract shorelines from the consecutive images taken by the low altitude Helikite remote sensing platform, active contours without edges (ACWE) is used. Edges or boundaries exist primarily on places between one type of objective and the other. Since the hydrodynamic pressure has an effect everywhere, the locations of the waterlines can be the isobath lines. We could map several waterlines, which would enable us to complete a local bathymetry map ranges from 35 to 60 cm depth. The error resulting from applying ACWE algorithm to the imagery to determine the waterline is approximately less than 1 m. Therefore, it is very unique way to obtain such high resolutions of bathymetry with high accuracy for the regions of extremely high tidal ranges for a short time.  相似文献   

Nature and stability of atoll island shorelines: Gilbert Island chain,Kiribati, equatorial Pacific     

EUGENE C. RANKEY 《Sedimentology》2011,58(7):1831-1859

Islands rimming Pacific atolls typically form narrow, low‐lying lands that are commonly perceived to be particularly vulnerable to global changes such as sea‐level rise. As these, low islands form the only habitable land for many island nations, understanding the character of shorelines, and the rates and controls that operate to bring about changes, is an issue of central importance. The purpose of this study is to unravel the characteristics of coastal change on atoll islands of the Gilbert Island chain of the equatorial Pacific nation of Kiribati, especially as they relate to autogenic shoreline processes and El Niño/Southern Oscillation variability. Integration of field observations, differential global positioning system data, historical aerial photographs and ultra‐high resolution remote sensing images demonstrates the nature, spatial patterns and rates of change from 17 islands on Maiana and Aranuka atolls. The results illustrate that, between 2005 and 2009, ca 50% of the shorelines on these islands displayed a discernable shift in position; some shorelines were accretionary (at net rates up to ca 8 m year^?1) and others were erosional (up to ca 18 m year^?1). Long‐term net rates of change on Maiana between 1969 and 2009 were lower than short‐term net rates measured between 2005 and 2009. Both short‐term and long‐term observations illustrate some of the greatest change occur near terminations of the largest, north–south oriented islands, associated with longshore movement of coarse sand and gravel. Direct hits by tropical depressions and marked seasonality, factors interpreted as being essential in island growth and shoreline dynamics elsewhere, do not directly impact these equatorial atolls and can be eliminated as fundamental controls on shoreline dynamics. Similarly, observations over four years suggested that shoreline variability probably is not influenced directly by marked sea‐level change, although a recent increase in the rates of shoreline change could reflect instability related to the cumulative effect of a long‐term increase in the rate of sea‐level rise. Within this framework of global change, local anthropogenic effects, autogenic shoreline processes and El Niño/Southern Oscillation‐influenced wind and wave variability control many aspects of these dynamic shorelines. These results provide quantitative insights into the character and variability of rates of shoreline change, information essential for evaluating and mitigating the vulnerability of island nations such as Kiribati.  相似文献   

Evaluating delta asymmetry using three‐dimensional facies architecture and ichnological analysis,Ferron ‘Notom Delta’, Capital Reef,Utah, USA     

WEIGUO LI  JANOK P. BHATTACHARYA  YIJIE ZHU  DANIEL GARZA  ERIC BLANKENSHIP 《Sedimentology》2011,58(2):478-507

Delta asymmetry occurs where there is strong wave influence and net longshore transport. Differences in the morphology and facies architecture between updrift and downdrift sides of asymmetric deltas are potentially significant for exploration and exploitation of resources in this class of reservoirs. Although delta asymmetry has been recognized widely from modern wave‐influenced deltaic shorelines, there are few documented examples in the ancient record. Based on an integrated sedimentological and ichnological study, the along‐strike variability and delta asymmetry within a single parasequence (Ps 6) is documented in continuously exposed outcrops of the Cretaceous Ferron Sandstone Member of the Mancos Shale Formation near Hanksville in southern Utah. Two intra‐parasequence discontinuity surfaces are recognized which allow subdivision of the parasequence into three bedsets, marked as Ps 6‐1 to Ps 6‐3. Four facies successions are recognized: (i) wave/storm‐dominated shoreface; (ii) river‐dominated delta front; (iii) wave/storm‐reworked delta front; and (iv) distributary channel and mouth bar. Dips of cross‐strata within distributary‐mouth bars and shorefaces show a strong downdrift (southward) component. Ps 6‐3 predominantly consists of river‐dominated delta‐front deposits, whereas Ps 6‐1 and Ps 6‐2 show an along‐strike facies change with shoreface deposits in the north, passing into heterolithic, river‐dominated delta‐front successions south to south‐eastward, and wave/storm‐reworked delta‐front deposits further to the south‐east. Trace fossil suites correspondingly show distinct along‐strike changes from robust and diverse expressions of the archetypal Cruziana Ichnofacies and Skolithos Ichnofacies, into suites characterized by horizontal, morphologically simple, facies‐crossing ichnogenera, reflecting a more stressed, river‐dominated environment. Further south‐eastward, trace fossil abundance and diversity increase, reflecting a return to archetypal ichnofacies. The overall facies integrated with palaeocurrent data indicate delta asymmetry. The asymmetric delta consists of sandier shoreface deposits on the updrift side and mixed riverine and wave/storm‐reworked deposits on the downdrift side, similar to that observed in the modern examples. However, in contrast to the recent delta asymmetry models, significant paralic, lagoonal and bay‐fill facies are not documented in the downdrift regions of the asymmetric delta. This observation is attributed to a negative palaeoshoreline trajectory during delta progradation and subsequent transgressive erosion. The asymmetric delta was induced by net longshore transport from north to south. The forced regressive nature of the delta precludes significant preservation of topset mud.  相似文献   

国际海岸线变化研究进展综述——基于文献计量学方法   总被引：1，自引：0，他引：1       下载免费PDF全文

张玉新  侯西勇 《应用海洋学学报》2020,39(2):289-301

以SCIE数据库为基础,基于1024篇文献和VOSviewer(Visualization of Similarities Viewer)文献网络分析软件,运用文献计量学方法分析1970年以来国际海岸线变化研究的发展特征,并结合文献综述方法,归纳海岸线变化研究主要涉及的科学问题及研究热点。研究表明:近50年来,国际上海岸线变化研究文献发文量整体呈上升趋势,主要涉及地球科学、环境科学和自然地理等学科,《Journal of Coastal Research》是此主题最主要的发文期刊;美国及其国内的地质调查局、杜克大学和佛罗里达大学一直引领该领域的研究及其发展,并形成以其为核心的主要合作集群;岸线侵蚀一直是该领域研究的重点问题,遥感和GIS逐渐发展为岸线变化研究的主要手段,海岸线变化的驱动力分析及模拟预测、岸线变化的自然与社会效应以及海岸带综合管理研究成为近年来的研究热点;中国在该领域的研究起步较晚,但发展迅速。本研究对促进我国海岸线变化研究的发展及海岸带综合管理实践有较好的参考和借鉴作用。  相似文献   

闽中南海岸风沙灾害的形成与年代     

周定成  王金坑 《台湾海峡》2010,29(1):94-98

闽中南海岸风沙灾害曾经十分严重，是海岸灾害史上的一次重大事件．本文通过历史考证和综合研究认为，灾害形成于明代万历年间（1573—1578年或1595年以后），主因是明代万历年间旱作农业（甘薯等）在沙地大规模垦植，破坏海岸森林植被，触动本区海岸自然生态脆弱方面而引发的．此后又有清代初期的“迁界”等不良社会政治因素的作用而复发与加剧．灾害历经360a或380a多，至1958年以后才得以初步治理成功．当今此灾害已成为历史，但其教益深刻，今后应进一步加强海岸林业的生态建设．  相似文献   

遥感和GIS支持下的九段沙岸线提取及变迁研究   总被引：2，自引：0，他引：2  

冯永玖  刘丹  韩震 《国土资源遥感》2012,(1):65-69

在遥感和GIS的支持下,利用集成了非监督分类、地图综合、离散地物去除和岸线追踪等技术的shoreline-Extractor软件,解译上海市九段沙自然保护区2001年、2005年和2008年的岸线信息;对解译的目标岸线分别进行空间分辨率为30 m,90 m,150 m,210 m和270 m的重采样,计算其分维数,并进行岸线长度、沙洲面积和分形特征的分析,进而对九段沙岸线变迁的重点区域进行了分析。研究表明,随时间推移,九段沙的上沙、中沙和下沙3个沙洲淤长的部位并不一致,其中上沙北部区域、中沙东北和西南区域、下沙东北和西南区域淤长较为明显;岸线长度与沙洲面积的变化区域几乎一致,即上沙增长较快、下沙次之、中沙缓慢;九段沙岸线具有显著的分形性质,整体分维数呈增加态势,其中上沙和中沙的分维数小于整体分维数,而下沙的分维数大于整体分维数。  相似文献   

基于改进标记分水岭的高分辨率遥感影像海岸水边线提取方法          下载免费PDF全文

栾奎峰  刘帅  潘与佳  朱卫东  李丕学  裘诚  邱振戈  沈蔚  王洁  王振华 《海洋学研究》2021,39(1):20-28

利用遥感技术快速提取海岸线是一种重要的技术手段,针对传统分水岭算法在高分辨率多光谱卫星数据处理中存在的过分割和抗干扰能力差的问题,本文提出了一种基于扩展极值变换标记分水岭的算法。首先通过形态学重建、扩展极值变换等方法建立前景和背景标记,初步抑制灰度极小值和极大值区域,然后依据这两类标记对梯度图像进行修正,进而进行分水岭变换,提取岛屿水边线。以南海典型海岛为研究区域,利用2017年GF-2卫星数据对本文提出的方法进行验证和精度评价,研究结果表明:改进的分水岭算法对GF-2数据的人工岸线提取质量在1个像素(4 m)之内高于90%,沙质岸线提取质量在1.5个像素(6 m)之内高于90%,可以用于高分辨率多光谱影像的分割和海岛水边线的提取。  相似文献   

THE MEMPHIS MEETINGS     

《The Professional geographer》2013,65(1):20-21

The case of a New Jersey dune management plan demonstrates that geographers can initiate environmental policy by formulating and proposing meritorious plans. An evaluation of the plan's rejection shows the complexity of policy-making and indicates that failure to adopt useful plans may be due to distortion of information or misunderstanding of the original plan. In order to avoid failure, geographers should participate in the entire policy-making sequence and should encourage the participation of the public who will be affected by the plan.  相似文献   

1973—2018年珠江三角洲海岸线时空演变分析   总被引：1，自引：0，他引：1       下载免费PDF全文

夏涵韬  隆院男  刘诚  刘晓建 《海洋学研究》2020,38(2):26-37

通过遥感和GIS技术获取1973—2018年的Landsat TM/OLI遥感影像为数据源,结合地理背景资料,分析45 a来珠江三角洲地区海岸线时空演变情况。结果表明:珠江三角洲地区海岸线变迁显著,大量的淤泥质岸线转变为城镇工业岸线和港口岸线,珠江三角洲地区岸线人工化指数不断上升,岸线类型朝向多元化方向发展,岸线总长度和分形维数不断增加,港口建设、滨海工业区、围垦填海等是岸线长度和分形维数增加的主要因素;海岸线演变呈现明显的区域特征,变化较大区域主要集中在深圳大鹏湾、广州南沙和珠海斗门;从岸线开发利用主体结构上看,各大岸区都出现了不同类型的变化趋势,城镇工业岸线与港口岸线取代自然岸线成为各区海岸线的主体类型;各地区开发利用强度不断上升,其中深圳市开发强度增速最快,社会活动和区位政策是引起岸线演变的主要驱动因素。  相似文献   

Shoreline oscillation of Dhanushkodi,Rameswaram, India     

Usha Natesan  R. Vishnunath  K. Kathiravan 《国际地球制图》2015,30(5):520-531

Rameswaram Island located on the southeast coast of India bounded by Gulf of Mannar (GoM) on the south and Palk Bay (PB) on the north, respectively, is unique in nature. The southeastern part of Rameswaram Island known as Dhanushkodi foreland is a long sand spit of about 20?km length. Shoreline erosion/accretion rates are computed based on End-Point Rate, Linear Regression Rate and Net Shoreline Change from Indian Remote sensing Satellite, Linear Imaging Self scanning Sensor III images from 1998 to 2012. Along the PB coast of Dhanushkodi foreland, eroding shorelines are dominant except Arichamunai, whereas it is reversing along GoM. Inter-annual shoreline change revealed that changing trend and stability of Island are affirmed with statistical approaches. An equilibrium shoreline trend is noticed on both the sides of Dhanushkodi foreland. Annual shoreline change rate indicates erosion and accretion in northern and southern coastline of Dhanushkodi foreland varies, respectively.  相似文献