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101.
102.
为治理河口拦门沙,实施了通过整治及疏浚的方式打通拦门沙的射阳港双导堤工程,导堤的功能定位为“导流、挡沙、减淤”。通过对江苏盐城射阳港海岸动力地貌等环境的调查,分析研究射阳港区不同时期的水下沉积物分布特征、不同历史时期的水下地形特征,同时研究不同时期的水质、底质沉积物、生态群落等指标数据,对射阳港双导堤建设的环境影响进行后评价。研究认为:双导堤工程完工后导堤口区域出现明显冲刷,导堤两侧出现淤积,颗粒变细,但对水质环境、底质沉积物环境和生态环境的影响不大,双导堤工程建设对环境影响的风险可控。 相似文献
103.
104.
洋山港海域大型污损生物生态特点 总被引:2,自引:2,他引:2
洋山港是上海国际航运中心的枢纽港。为了解该海域污损生物的群落结构及演变趋势,2009年3月至2010年3月在洋山港海域进行了周年污损生物挂板调查研究。洋山港海域污损生物种类较少,共记录污损生物19种,隶属于5个类群,优势种为僧帽牡蛎(Ostrea cucullata)、网纹纹藤壶(Balanus reliculatus) 、大室膜孔苔虫(Membranipora grandicella)、厦门华藻苔虫(Sinoflustra amoyensis)、双钩楯琥珀苔虫(Aspidelectra bihamata)、中胚花筒螅(Tubularia mesembryanthemum)、曲膝薮枝螅(Obelia geniculata)和亚洲帚毛虫(Sabellaria ishikawai),种类组成以广布种为主,同时部分具有河口低盐种的特征;污损生物的附着高峰期是6—10月份,除冬季月份外,其余月份均有生物附着;受盐度、水流及泥沙含量的影响,洋山港污损生物的生物量变化较大,月板、季板及年板的平均附着生物量分别为9.20,127.20和774.04 g/m2。另外,通过对洋山港海域污损生物周年的物种组成和群落结构变化分析,发现该海域污损生物群落受季节变化和盐度的升高影响较大,群落结构不稳定,物种演替明显。 相似文献
105.
地缘经济合作背景下的中国磨憨-老挝磨丁口岸地区建设用地扩张 总被引:1,自引:0,他引:1
20世纪90年代以来,在地缘经济合作机制的影响下,作为中南半岛唯一的内陆国家,老挝边境地区正在经历以建设用地扩张为主的土地利用与覆被变化(LUCC)。本文以中老磨憨-磨丁口岸为例,基于2016年2月-2018年11月10期Sentinel-2 A/B 10 m分辨率遥感影像,利用面向对象与分类后目视修改相结合方法提取2016-2018年磨憨-磨丁口岸15 km缓冲带的建设用地分布信息,并分析了建设用地的时空变化及国别差异。研究结果表明:① 中老磨憨-磨丁口岸地区经历了阶段性快速发展,由2016年年初的1098.8 hm 2激增到2018年年底的2238.8 hm 2,增加了1140.0 hm 2,其中50.8%的新增建设用地集中在海拔800~1000 m,80.9%在坡度20°以下;② 中国磨憨口岸侧建设用地占研究区建设用地的比重从63.3%递减至54.8%,但仍占规模优势,由695.4 hm 2猛增到1226.7 hm 2,平均增幅6.7%;③ 老挝磨丁口岸侧建设用地增加近1.5倍,从403.4 hm 2剧增到1012.1 hm 2,平均增幅11.1%,占比由36.7%递增到45.2%。可见,日益发展的地缘经济合作是推动中老两国边境地区(特别是口岸)土地利用变化的主要诱因。 相似文献
106.
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. 相似文献
107.
浙江北关港污损生物的群落结构及其主要影响因子 总被引:1,自引:1,他引:0
于2016年3月至2017年2月在浙江北关港附近海域进行污损生物周年挂板试验,全年共记录大型污损生物9门44科53属59种,种类组成以近岸暖水种为主,属于典型的亚热带内湾型污损生物群落。固着生活类型的悬浮物食者是该海域污损生物群落的优势群体,群落最主要的优势种是网纹藤壶(Amphibalanus reticulates),其次为长鳃麦秆虫(Caprella equilibra)、中胚花筒螅(Ectopleura crocea)、太平洋侧花海葵(Anthopleura nigrescens)、廉形叶钩虾(Jassa falcata)和强壮藻钩虾(Stenothoe valida)等种类。该海域污损生物全年各月均有附着,6-10月板的覆盖面积均达100%,附着盛期为6-8月,月板、季板、半年板和年板的平均附着密度和生物量分别为(21 371±8 722) ind/m2和(1 667.5±506.0) g/m2,(31 605±17 671) ind/m2和(5 879.1±2 576.5) g/m2,(31 188±10 834) ind/m2和(13 989.6±4 755.4) g/m2,(18 425±5 757) ind/m2和(6 581.9±2 175.9) g/m2,其中夏季附着强度最高。污损生物群落个体间因栖息空间和食物竞争而存在着相互依存或互相制约的关系,又依照对环境的适应性而存在着一定的时空分布规律。分析表明,温度是决定污损生物地理分布的最主要环境因素;另外,盐度、水体透明度以及光照等自然环境也是影响污损生物附着的重要影响因素。 相似文献
108.
目前,针对港口溢油巡航监测缺乏行之有效的技术手段。为探索激光诱导荧光光谱技术应用于港口溢油监测的可行性,以微型光纤光谱仪搭建小型激光荧光遥测实验系统,并对其性能进行测试分析。结果发现,在光谱仪曝光时间设为最小(1.11 ms)的情况下,环境光对荧光测量仍会产生影响,利用减背景法可以有效去除溢油荧光信号中环境光的影响;在相同条件下,系统测得不同油质溢油样品的荧光光谱表现出不同的光谱特征,轻质油较重质油的荧光峰蓝移、荧光更强;在上述环境光背景影响和光谱测量分析的基础上,进一步测试了系统的信号探测稳定性,结果显示,系统重复测量的相对标准偏差RSD=2.54%,表明该系统具有较好的信号探测稳定性。综上,基于微型光纤光谱仪的小型溢油激光荧光遥测系统可望在近岸港口溢油巡航监测中发挥重要作用。 相似文献
109.
Lynette C. McLoughlin 《The Australian geographer》2000,31(2):183-208
Described by Governor Phillip as 'the finest harbour in the world', Sydney Harbour was affected by accelerated sedimentation very soon after settlement in 1788. Dredging began in 1842 to deal with the problems caused by sedimentation and to enhance foreshore amenity. By the end of the nineteenth century, dredging was also excavating the bottom of the Harbour and its bays to accommodate larger ships with deeper draughts, and dredged sediment was increasingly used to reclaim mudflats or marshes deemed unhealthy or unsightly, thereby creating additional useful waterfront land. There was virtually continuous dredging in some part or other of the Harbour and its tributaries for almost 140 years. With increasing costs and mounting environmental concerns, dredging is now intermittent, and carried out largely to facilitate navigation for specific projects, despite continued sedimentation. While there was an early lack of understanding of the Australian environment and the impact of clearing on soils, the causes of increased sedimentation had been documented by the 1860s. However, measures to seriously address causes were not introduced until late in the twentieth century. This paper briefly outlines the development of the Sydney estuary to 1788, considers the impact of settlement in accelerating sedimentation, traces the development of dredging and reclamation, and discusses their significance for a number of areas of current research and environmental management, as well as to social and economic history. Within the limitations of the data available, annual sediment dredged, annual expenditure, cost per tonne, and areas reclaimed by dredging and filling are included. 相似文献
110.
Target factors aim at setting criteria to select foreign vessels that should be inspected by port state control authorities. Although a relative consensus exists on the main factors to consider in selecting vessels, the weight to be given to these factors is still unclear. Using data on 26 515 PSC inspections that took place within the Indian Ocean MoU region from 2002 to 2006, we investigate the determinants of the number of deficiencies and of the probability of detention. Our results show that the main contributors to detention are the age of the vessel at inspection (40%), the recognised organization (31%) and the place where the inspection occurs (17%). Also, differences in detention rates amongst various inspecting authorities are essentially explained by differences in the characteristics of vessels calling in a specific country rather than by differences in the way inspections are done. 相似文献