【作者】 彭修强；

【导师】 王颖；

【作者基本信息】 南京大学 ， 自然地理学， 2012， 硕士

【摘要】 海岸带是陆地与海洋相互交接的特殊地带,具有丰富的资源禀赋与优越的自然条件,是人类赖以生存和发展的重要栖息地,也是现代经济社会和文化发展的前沿基地。海岸带区域岸线变迁及水下地形的冲淤演变,将会直接改变潮间带的滩涂资源量和海岸带生态环境,引起海岸带诸多资源与生态过程的改变,对人类的生存环境、国民经济建设发展等产生重要的影响作用,历来受到世界的广泛关注。因此,加强海岸的演变研究对于了解海岸带生态环境变化,服务沿海地区经济社会发展乃至全球变化的研究均具有重要的现实意义。本文以多期地形图、海图,多时相卫星遥感影像数据以及多年实测数据为主要数据源,将地理信息系统(GIS)、RS和数字高程模型(DEM)应用于废黄河三角洲岸线变迁及水下地形冲淤演变分析中,建立了区域海岸线和水下地形数据库,通过不同时期岸线和水下地形数据的叠加,获得了岸线变化及水下地形冲淤变化的定量化信息。研究结果表明：(1)自春秋以来,废黄河三角洲海岸线经历了由快速向海方向推进转而又向陆侵蚀内移并逐渐趋于稳定的过程。春秋至北宋(公元1111年)间岸线整体保持顺直,长度变化不大；其后大致以1890年为界,1330—1890年间岸线长度整体保持增长态势(1760年统计时包含了河口外沙洲岸线),1890—1958年由于受到黄河北归的影响,岸线长度逐渐减小。(2)自1970年代以来,废黄河三角洲不同岸段海岸线的时空变化特征相对比较复杂。中山河口至扁担河口岸段是废黄河三角洲海岸的主要侵蚀区,但侵蚀强度逐渐减弱。废黄河口地区分别于1967—1981年、1986—1996年和1998—2008年三个时段进行了保滩护岸工程,河口尖护岸工程对附近海岸起到了屏障作用,1995年以后该段海岸侵蚀速率明显减缓。整个侵蚀区不同部位的蚀退速率有差异,废黄河口北部蚀退速率小于河口南部。扁担河口以南则呈蚀淤交替的态势,可能受1986年在射阳河口以北栽种互花米草的影响所致。(3)1930-47至1979年废黄河水下三角洲全区以侵蚀为主,沿岸、废黄河尖北部以及外海大致-18m以深区域淤积显著。整个区域净冲淤量为-44.2×108m3,年均净冲淤速率为-1.105×1081m3,年均冲淤厚度约为-1.06cm/a。(4)滨海港区域1989—1994年间除废黄河口北部沿岸和外海东南部微弱淤积外,绝大部分呈冲刷状态。至2007年废黄河尖外部海域已冲刷出一宽度>lkm、水深>-15m的冲刷深槽,方向大致与等深线平行。(5)水下地形冲淤结合水深断面的分析表明,除中山河口北侧断面外,废黄河水下三角洲水下岸坡侵蚀形态均表现为下凹形,侵蚀下限大致在-12m--15m水深部位,可能指示了波浪作用的最大下限在-15m水深左右。结合各断面各水深部位的冲淤速率分析,侵蚀强度最大的部位约在-3m--12m之间。以废黄河口为界,北部各断面水下平原部分以冲刷为主,而南部各断面则以淤积为主。由于目前尚无覆盖全区范围的晚于1979年的实测水深资料,而重复测量资料也仅限于局部,因此尚难以总结出近期全区整体的水下地形冲淤演变动态。更多还原

【Abstract】 The coastal zone, located at the area of land and sea interactions with rich resources endowment and favorable natural conditions, is an important habitat for human survival and development, it is also the forward base of social economic development and modernization, as well as the civilization. Coastline and coastal morphological erosion or deposition will directly impact the coastal resources amount and ecological environment, as a result, it will significantly impact on the human living conditions, economic construction etc. Thus, the problems have attracted worldwide attention. Therefore, to strengthen the study on coastal evolution has an important practical significance for understanding the coastal eco-environmental changes, serving the economic and social development as well as global changes in coastal areas.Based on the regional topographic maps, charts, multi-temporal satellite remote sensing images and annual measurement data,a geodatabase of coastlines and subaqueous reliefs was established by geographic information system(GIS), RS, digital elevation model(DEM). Quantitative information of shoreline and the underwater terrain changes was calculated by using the superposition of different periods of shoreline and underwater terrain data.The results are shown as follows:1. Since the Spring and Autumn Period, the coastline of the abandoned Yellow RiverDelta has experienced a process of promoting the transfomation of rapid progradation to retreat and gradually stabilized. The shoreline kept straight and had little length change from the Spring and Autumn Period to the Northern Song Dynasty (1111A.D.) as a whole:roughly to1890A.D.for the sector in the remaining years, the overall growth momentum was maintained(1760A.D. with sandbar shoreline) from1330A.D. to1890A.D., however, due to the north migration of the Yellow River, the length of coastline gradually reduced from1890A.D. to1958.2. Since the1970s, the abandoned Yellow River Delta coastline has experienced more complex spatial and temporal variation.The main eroded area is located within the range from Zhongshan River mouth to Biandan River mouth, while the erosion intensity has gradually weakened. Coastal protection projects were implemented separately inl967-1981,1986-1996and1998-2008at the Abandoned Yellow River mouth. Revetment projects at the tip of the mouth played a role of protective barrier for the near coastline, as a result, the rate of erosion in this section had significantly slowed down since1995. Retrogradation rate varied in different parts in the whole eroded area, which is showed that the north of the Abandoned Yellow River mouth is lower than the southern. Possibly beening affected by the planting of alterniflora in the north part of Sheyang River mouth in1986, the south area of Biandan River mouth showed a trend of erosion and siltation alternatively.3. The entire region of the abandoned Yellow River subaqueous delta was scouring dominated from1930-47to1979. while the coastal areas, north of the the abandoned Yellow River tip as well as roughly-18m deep off the coast demonstiated evident siltation. The net erosion and deposition of the entire region was-44.2×108m3, averaging-1.105×108m3per year, and the average annual scouring and silting thickness was about-1.06cm/a.4. Except the north shore of the abandoned Yellow River mouth and along the north shore and the part off the coast of southeast were in weak deposition in Binhai Port from1989to1994, the vast majority was scouring. Till2007, the offshore waters in the abandoned Yellow River Tip has carved out a scouring groove with1km wide, deeper than-15m, of which the direction generally parallels to the isobath.5. The evolution of scouring and silting of the underwater terrain, combined with analysis of the depth sections shows that all the offshore slopes of the abandoned Yellow River subaqueous delta present up-convex erosion shape except the north Zhongshan estuary section.The lower limits of erosion are roughly at-12m～-15m depth, which may indicate that the lower limit of wave action is at about-15m water depth. Combined with the analysis of the erosion and deposition rate in each depth site, the place with the greatest erosion intensity is in about-3 meters to-12meters between. Setting the abandoned Yellow River mouth as borderline, the underwater plains of northern sections are mostly erosion based, while the southern section are depositing.There is no measured deptn data late in1979covering for the whole region, and repeated measurement data is limited to local, theverfore, it is still difficult to sum up the recent overall deposition and erosion evolution dynamics of underwater terrain for the whole region.更多还原