Google Earth: A New Resource for Shoreline Change Estimation—Case Study from Jaffna Peninsula,Sri Lanka

Abstract

Estimation of shoreline change using satellite images is considered as a very effective method because the coastline is found highly dynamic. This study focuses to develop a methodology to detect shoreline changes using satellite imageries obtained from Google Earth platform. The study was carried out in north-east coastline of Jaffna in Sri Lanka. Shorelines from 2002 to 2017 were delineated on the multi-temporal satellite images in the Google Earth software by visual interpretation and change was detected using Digital Shoreline Analysis System in ArcGIS. Tidal variation, digitizing error, and geometric errors were considered to calculate the uncertainty. Mean End Point Rate, mean Shoreline Change Envelop, mean Net Shoreline Movement, and mean Weighted Linear Regression Rate were used as main shoreline change statistics. Result shows that there is net shoreline accretion of 6.13?±?8.74 m with an annual rate of deposition of 0.5?m/year. During the study period, 76.12% of the observed shoreline is found accreted while the 23.88% of the shoreline is eroded. Mean Uncertainty of the shoreline is 3.73?±?0.59 m. The study revealed that the satellite images from Google Earth platform can be used for time series analysis of shorelines after appropriate corrections.     

基于遥感的珠江口海岸线变迁分析

利用1990年、2000年和2010年三个时相的遥感影像,进行2000年前后两个十年的海岸线变迁情况对比分析。结果表明:2000年前的十年间,珠江口海岸线向海推进,导致面积共增加了16486.63ha,主要受人为因素影响,围海养殖是本时段海岸线变迁的主要因素;2000年后的十年间,珠江口海岸线继续向海推进,但推进速度降低,导致面积增加了9280.15ha,填海造地是这一时段海岸线变迁的主要因素。又根据珠江口的区域特征,以珠江入海八大口门为界,将整个研究区划分为九个岸段进行了详细分析。     

Assessment and prediction of shoreline change using multi-temporal satellite images and statistics: Case study of Damietta coast,Egypt

The shoreline trajectory of Damietta city, locates at the Northern coast of Egypt, is dramatically subjected to kinematic changes. These variations mainly occur based on the incessant duel hydrodynamic impacts of both wave action and coastal currents. Several types of coastal measures have been applied substantially along the coastal stretch of Damietta to protect shoreline such as detached breakwaters, Jetties, groins, and seawalls. This study is essentially focused on the assessment of shoreline kinematics response due to the existence of these structures during the period from 1990 to 2015. In addition, the future changes of the shoreline at 2020, 2025 and 2035 are predicted using satellite images, Geo-spatial tools and Digital Shoreline Analysis System (DSAS) by the meaning of End Point Rate (EPR) and Linear Regression Rate (LRR) methods. Four Landsat images at different periods; TM1990, TM 1999, ETM 2003 and ETM 2015 are used to detect shoreline changes. Three semi-automatic extraction techniques are initially tempted for Landsat ETM 2003 imagery namely; Iso cluster technique, threshold method, and onscreen digitizing method to select the optimal one. Iso cluster technique is used as the optimal technique which achieves the least errors with the corresponding field data in 2003 by value of 0.34. Furthermore, the extraction shoreline change for Damietta coast is extensively measured for three zones: zone (1) the western sector encompassing Damietta port with two jetties; zone (2) the central sector including detached breakwaters; zone (3) the eastern portion of Damietta estuary passing through a seawall. Verification analysis shows that the EPR is the optimum method for shoreline detection with a value of RMSE by 0.27. The results show that, for zone (1), the western shoreline of Damietta port is progressed by a rate of +10.0 m/year. On the other hand, the shoreline on the down drift side at zone (2) has retreated by a rate of -5.0 m/year. While the shoreline behind the detached breakwaters in the central sector has advanced by +12.0 m/year from 1999 to 2003, then decreased gradually until become stable in 2015. For zone (3), alongshore currents have derived the disassembled sandy soil from west to east leaving a highly eroded area by average rate of -78m/year. The results of this study give indication to shoreline trend of near future which should be under consideration in planning of Damietta coastal zone.     

近50年来广西海岸滩涂变化特征分析

作者利用不同时段的遥感影像、数字化地形图和历史航空相片,在地理信息系统平台上提取广西海岸滩涂的变化资料,并对其进行分析。结果表明,近50 a来广西海岸滩涂的变化特征为:滩涂面积经历了由加速递减(1955～1977年)、滩涂面积变化基本不变(1978～1988年)到滩涂面积再次递减的3个阶段(1988年以来),其中滩涂面积变化最大的是沙砾质滩涂,其次是红树林滩涂,这两类滩涂面积减少最多、递减速率最快。     

Integrated Assessment of Shoreline Change along the Calypsostranda (Svalbard) from Remote Sensing,Field Survey and GIS

Abstract

Arctic coasts are sensitive indicators of polar environment change. Here we present the results of a study that examines the coastal morphodynamics of the Calypsostranda coastline in Svalbard (High Arctic) between 2007 to 2017 and compare these short-term changes to previous studies for the period 1936–2007. During the 2007–2017 study period, the study area lost ca. 10,710 m², at a mean Net Shoreline Movement (NSM) of ?1.86 m and End Point Rate (EPR) ?0.19 m/yr. Erosion also dominated between 1936–2007, ?28,800 m², at a mean NSM of ?4.99 m and EPR ?0.07 m/yr. Using EPR and Linear Regression Rate (LRR) parameters, we divide the Calypsostranda coastline into eroding and aggrading zones. The overall pattern of coastline change during the two study periods is similar, but the rate of erosion is higher in the recent interval, reflecting stronger climate-driven processes. Recent climate warming in the study area has been accompanied by an intensification of extreme events such as storms (e.g. ocean swell). The situation is becoming more pronounced due to the progressively reduced period of winter shore ice. Depending on the anemometric conditions, the Calypsostranda coast is modified by wind waves, and consequently longshore currents and associated sediment movement.     

基于数字化海岸分析系统(DSAS)的海岸线变迁速率研究:以黄河三角洲和莱州湾海岸线为例

海岸线变化对海岸带生态环境改变、滨海土地侵蚀有着极其重要的影响,海岸线的提取和监测对海岸带生态系统的保护和管理具有重要意义。本研究基于数字化海岸线分析系统(DSAS,Digital Shoreline Analysis System),研究了黄河三角洲和莱州湾的海岸线时空变化规律。研究结果表明:通过提取1985-2015年6期的Landsat影像,发现近30年来黄河三角洲和莱州湾地区海岸线均呈现显著的向海方向扩张的趋势,且增长速率逐渐加快。黄河三角洲的终点变化速率(EPR,End Point Rate)约为73.0 m/a、线性回归速率(LRR,Linear Regression Rate)约为75.5 m/a,黄河港-大咀沟增长速度最快(129.2 m/a),受黄河泥沙输送的影响,黄河口和老黄河口岸线的几何形态呈现平滑的变化趋势;莱州湾岸线的EPR和LRR约为139.5 m/a和144.3 m/a,淄脉河河口-白浪河河口段增长速度最快(197.6 m/a),岸线变化较为显著的区域主要集中在港口、圈海堤坝、海水养殖等的地方。DSAS模型在海岸线定量化分析中具有显著优势,利用EPR和LRR指标能够科学有效地模拟岸线在时间和空间上的变化速率。     

基于遥感的广西防城湾海岸线变迁分析

随着人口增长、城市化和工业化的迅速发展、政策刺激以及对外贸易的日渐加强,防城湾沿岸海岸线变迁加剧。本文利用1973,1979,1990,2000年的Landsat卫星遥感影像和2010年的HJ-1B(环境与灾害监测预报小卫星星座B星)卫星遥感影像,分析了近40 a来防城湾海岸线的变化特征。结果表明:1973—2010年间,防城湾沿岸不断向海推进,陆域面积共增加了4 216.61 hm²;海岸线总长度则减少了36.96 km,其中淤泥质岸线减少最为剧烈,其次为基岩岸线;海岸线变化主要受人为因素影响。根据防城湾的区域特征,将整个研究区划分为防城江口、暗埠口江和渔澫岛3个岸段分别进行详细分析表明:防城江口沿岸以基岩岸线为主,海岸线在1973—2010年间变迁程度很小,仅在防城江河口沿岸向海扩张了约74.58 hm²;暗埠口江沿岸以淤泥岸线为主,近40 a间该岸段岸线不断向海推进,许多原本曲折多变的鹿角湾被逐渐填充;渔澫岛海岸线变迁最为剧烈,近40 a来陆域面积共增加了2 027.41 hm²,岸线长度缩短了2.46 km,遥感影像监测显示1990年时渔澫岛已经陆连,同时从渔澫岛的分形维数计算结果可以看出其海岸线日趋平直。     

基于遥感和GIS相结合的广西海岸线时空变化特征分析

利用不同时段的遥感影像、数字化地形图和历史航空相片,在地理信息系统平台上获取广西海岸线的时空变化资料,并对其进行分析。结果表明:(1)近50年来,广西海岸线总的长度减小,在1955—1998年期间岸线长度呈递减趋势;(2)岸线由曲折向平直化演变,其中围垦段的岸线相对平直;(3)风流岭江南岸及企沙东面鹿墩岛海岸的自然侵蚀幅度不大,岸线变形较小。     

1973 年以来射阳河口附近海岸蚀淤变化遥感分析

以射阳河口北部扁担港口和射阳河口南部斗龙港口之间的海岸作为研究区,基于1973,1987,2000和2013年四期Landsat影像提取了该岸段岸线,并进行了时空变化分析。结果表明,射阳河口以北的扁担港口—射阳河口岸段仍处于侵蚀状态,呈现侵蚀—淤积—缓慢侵蚀的变化格局,40 a间侵蚀面积为12.6 km2,淤积面积为1.0 km2;射阳河口以南的射阳河口—斗龙港口岸段处于淤积的态势,呈现淤积—快速淤积—缓慢淤积的格局,40 a间淤积的面积为223.1 km2,仅在2000~2013年间该岸段北部出现了侵蚀。结论是虽然射阳河口以南岸段仍总体处于淤积的过程中,但是近年来江苏海岸的侵蚀范围已经扩展到了射阳河口以南,这证明了江苏海岸侵蚀岸段有进一步扩大的趋势。     

近50 a来秀山岛岸线时空变化规律及其原因浅析

海岸线是十分重要的自然资源,海岸线的变化会影响生态平衡与人们的生活。本文以浙江省秀山岛1970、1980、2003、2008和2014年的遥感影像作为数据源,利用遥感和GIS技术方法,并采用DSAS的岸线分析方法揭示了秀山岛近50 a来岸线的时空变化规律。结果表明:在自然和人为的双重因素影响下,秀山岛的自然岸线和人工岸线发生大规模的变化,岸线长度总体上是减少的,共减少4 226 m,新增陆域面积2.491 km²;其中人工岸线减少了4 046 m,海塘面积增加1.971 km²,表现为大规模的向海推进,时空变化显著;自然岸线减少了214 m,主要是沙质岸线和淤泥质岸线的变化,整体表现为岸线小规模的后退,但是局部地区有向海推进的现象。     

Invading cord grass vegetation changes analyzed from Landsat-TM imageries: a case study from the Wanggang area, Jiangsu coast, eastern China

Cord grass colonization on the Jiangsu coast, eastern China, modifies the native salt marshes in terms of ecosystem structure. The Landsat TM images from 1992 to 2003 were analyzed to identify salt-marsh vegetation distribution patterns and their changes over this coastal region, in order to evaluate the effects of the spreading of the artificially introduced halophyte Spartina. Supervised classification was performed using Bands 3, 4 and 5 in conjunction with in situ training samples, to derive the distribution pattern of the vegetation in the study area. Further, in order to identify the intertidal areas with different tidal elevations, a data treatment procedure was designed to combine regional water level data using harmonic analysis with the waterlines on the TM images extracted by density slice. The results show that: (1) the Spartina alterniflora area has been expanding towards the sea rapidly since it was introduced, especially at initial stages; (2) in the upper part of the inter-tidal zone, the local marsh plant Suaeda salsa and the exotic species Spartina anglica were present only near the sea dyke, occupying only a small part of the entire salt marsh, and the area of these two species has been reduced by land reclamation; (3) there has been a trend for Spartina alterniflora to become the dominant species in the salt marshes in the study area; and (4) the elevation of Spartina alterniflora’s seaward fringe was close to mean high water on neaps, and its landward boundary was slightly higher than mean high water. The salt marsh environment of the study area has been modified rapidly by the Spartina vegetation for the last 12 years.     

罗斗沙岛动态变化的遥感监测

罗斗沙岛是我国首批公布的可以开发利用的无居民海岛之一,属于泥沙岛,岛体极不稳定,动态变化比较大。本文利用1973—2011年间12个时相的遥感影像,分析了罗斗沙岛近40 a来的动态变化情况。研究结果表明:近40 a来,罗斗沙岛的位置、形状和大小均发生了较大的变化。罗斗沙岛的动态变化可分为3个阶段:第一阶段(1987年以前),罗斗沙岛为一个完整的岛体;第二阶段(1987—2001年),罗斗沙岛被分为东北和西南两部分;第三阶段(2001年至今),罗斗沙岛的西南部分消失,仅剩下东北部分。本文的监测结果可为编制罗斗沙岛的海岛保护与利用规划、制定海岛开发利用的具体方案、提出海岛的生态保护措施等提供数据支撑,进而为罗斗沙岛的生态保护和相关部门对其进行海岛管理提供服务资料。     

基于数字岸线分析系统的海岸线时空变化速率分析——以海州湾为例

本文选取1985−2018年间具有代表性的6期Landsat遥感影像,运用数字海岸线分析系统,综合利用面积法和基线法定量分析海州湾的岸线变迁,并进行岸线分类和驱动力分析。结果表明,30多年来海州湾岸线整体呈持续向海推进的态势,增长岸线比例总体处于不断增加的趋势,除了2005−2009年发生短暂的减小;1985−2018年,岸线长度增加了10.40 km,陆域面积增加了52.84 km²;海州湾岸线以人工岸线为主,且比重日渐增大,从1985年的47.90%到2018年的70.88%,前中期的沿海围垦养殖及后期的围海造陆是海岸线变迁的主要驱动力;其终点变化速率为26.09 m/a,净海岸线变化为155.12 m,记录增加总横断面在各个时期均大于50%,岸线变迁最剧烈的区域为新沭河−高公岛段,陆域增长点在于赣榆新城、连云新城建设和连云港港口建设。     

莱州湾西岸岸滩冲淤特征分析

利用风暴潮前后潮滩剖面的实测对比及不同时期地形图和卫星遥感影像解译分析,研究了莱州湾西岸海滩冲淤变化特征。结果表明,莱州湾西岸海滩中、高潮滩处于相对稳定状况,低潮滩呈现弱淤积的特征。岸线50多年来的总体变化特征是1986年以前岸线淤进蚀退变化较明显,1986年以来海岸线逐渐趋于稳定。分析表明,岸滩变化的原因主要为人类活动对岸滩形态的改造以及大风暴潮的影响。     

基于高空间分辨率卫星遥感影像的砂质海岸空间整治效果分析——以营口月亮湾为例

采用2005年采集的SPORT5卫星遥感影像和2015年采集的GF-1卫星遥感影像,分别对2006-2014年之间营口月亮湾海岸空间整治项目实施前后的海岸景观格局进行监测,在此基础上构建了沙滩面积系数、适宜游乐水域指数、主体功能度指数、景观多样性系数、景观变化指数等评估指标,评估了营口月亮湾海岸空间整治效果。结果表明:营口月亮湾沙滩养护工程实施后沙滩面积大幅增加,沙滩面积系数为2.44,适宜游泳嬉水娱乐区面积略有增加,适宜游乐区指数为1.10。海岸空间整理工程实施使月亮湾海岸游乐功能分区明显,月亮湖公园、高尔夫休闲区、山海广场区、农业生态旅游度假区和滨海嬉水观光区主体功能度指数分别达到0.89、0.76、0.68、0.65和0.77。海岸景观美化工程整体改变了海岸景观格局,使各功能分区海岸景观多样性提高,海岸景观格局更为优化,总体景观多样性系数达到1.13,景观变化指数达到0.30。     

苏北废黄河三角洲海岸时空演变遥感分析

基于遥感与地理信息系统技术,使用苏北废黄河三角洲海岸地区1978,1987和2000年的Landsat卫星遥感数据,选取岸线指标与波段,提取岸线信息,生成1978-1987年和1987-2000年海岸土地增减时空变化分布图,建立岸线变化距离及增速衡量指标,定量分析了废黄河三角洲海岸面积变化特征,以及灌河口-中山河口、中山河口-扁担港口和扁担港口-双洋河口以南岸段的时空变化格局与分布特征.研究结果表明,废黄河三角洲海岸的自然侵蚀速率呈减小趋势,但侵蚀作用仍在继续.侵蚀强度以废黄河口地区为中心,向南北两侧逐渐减弱.人工保滩护岸措施在一定程度上影响着自然侵蚀格局.其内部各岸段分别呈现缓蚀、侵蚀和基本侵淤平衡的变化格局.     

Impact of Brunswick River Mouth Training Walls on Adjacent Beaches, Brunswick Heads, New South Wales, Australia

1 .IntroductionTheBrunswickbeach barrierbegantodeveloparound 6 50 0yearsagoattheendofthepostglacialmarinetransgression .Onshoreandalongshoretransportofmarinesandsoccurredfollowingthestabi lizationofsealevelresultinginbeachandduneextensionwhichoccurredonmanyNSWbeachesuntilabout30 0 0to 1 0 0 0yearsBP (Roy ,1 980 ) ,followedbyperiodsofstabilitytorecession .TherecessionalongthenorthernNSWandsouthernQLDcoastisattributedtocontinuingnorthwardlongshoresandtransportestimatedatbetween 2 0 0 0 0 0m…     

基于GF-1卫星遥感影像的港口空间格局监测与评估——以营口鲅鱼圈港区为例

文章采用国产GF-1卫星遥感影像,通过对港口内部空间格局以及各组成单元特征进行分析,建立了面向对象的港口空间格局遥感监测方法与步骤,探索构建了码头岸线指数、码头岸线利用指数、码头指数、堆场指数和港池指数等港口空间格局集约利用评估指标,并以营口鲅鱼圈港区为例进行实证研究。结果显示:营口鲅鱼圈港区的码头岸线指数为0.51,码头岸线利用指数为1 498.16万t/km,码头指数为12.23hm~2/km,港池指数为242.76hm~2/km,堆场指数为108.46hm~2/km。码头岸线与码头面积、堆场面积、港池面积的基本比例为1.00∶12.00∶108.00∶250.00。营口鲅鱼圈港区仍有8 821.17万t/a的吞吐量提升空间。     

杭州湾北岸岸滩变化对海平面上升的响应——以龙泉—南竹港岸段为例

相对海平面上升引发的海岸潜在侵蚀是海岸带资源利用与规划的重点关注内容.基于杭州湾北岸龙泉—南竹港岸段实测断面资料,利用历史岸线后退和淹没法则计算法分析了该地区的海岸变化对海平面上升的响应.结果表明:近10 a来岸滩呈侵蚀后退趋势,年侵蚀速率为3.7～5.7 m/a,相对海平面上升对岸滩迁移后退的贡献为2％～6％;未来1...     

北太平洋亚热带环流区表层水中226Ra和228Ra的分布与变化

对1999年9～10月采自北太平洋亚热带环流区的19份表层海水样品的Ra同位素分析表明。研究海域表层水中的^226Ra、^228Ra放射性比度分别介于0．67～0．92、0．08～0．30Bq／m^3之间，平均值分别为0．74、0．11Bq/m^3．^226Ra/^228Ra)A．R．活度比的变化范围为0．11～0．44，平均值为0．19．上述数值明显低于近岸海域水体的相应值，表现为典型的开阔大洋水的特征．从空间分布的特征看，研究海域Ra同位素含量与^226Ra/^228Ra)A.R.值均呈均匀分布态势．将本研究结果与历史数据进行对比后发现，本研究获得的^226Ra、^228Ra放射性比度比20世纪60～80年代得到的数据来得低，可能与水体层化作用加强导致的Ra补充量的减少以及生物生产力升高导致的Ra迁出量的增加有关．北太平洋亚热带环流区表层水中Ra同位素的时间变化与文献报道的该海域叶绿素a、硅酸盐、磷酸盐含量与初级生产力的历史变化趋势相吻合．