长江口崇明东滩潮沟地貌形态和演变  

Topography and evolution of the tidal trench in the eastern Chongming tidal flat,Changjiang River Estuary

作　　者：刘建华[1] 杨世伦[1] 史本伟[1] 罗向欣[1] 付信坤[2] 

机构地区：[1]华东师范大学河口海岸学国家重点实验室,上海200062 [2]山东省兖州市第一中学,山东济宁272100

出　　处：《海洋学研究》2012年第2期43-50,共8页Journal of Marine Sciences

基　　金：国家自然科学基金资助项目(41071014);国家重点基础研究发展计划资助项目(2010CB951202);国家自然科学基金委创新群体项目(40721004);上海市科委资助项目(10dz1210505)

摘　　要：利用1994、2000和2009年的崇明东滩TM和ETM遥感图像和GIS技术确定潮沟的平面形态、量算了潮沟的长度和密度;在野外,利用RTK-GPS进行了典型潮沟的地形测量以确定潮沟的发育高程、宽度、深度、宽深比以及断面面积的纵向变化,并利用GIS技术建立了该潮沟的三维地貌模型。研究结果表明:(1)崇明东滩的潮沟主要发育在潮间带上部的盐沼中,北部和中部以单一微弯型潮沟为主,南部以树枝状潮沟为主。(2)1994年潮沟总长度为30.9 km,密度为717 m/km^2;因1998年的盐沼中上部围垦,2000年潮沟总长度和密度分别减少为11.1 km和459 m/km^2;近10a,因盐沼向海淤涨扩大,至2009年,潮沟总长度和密度又分别增大到31.8 km和981 m/km^2;3个时期的潮沟兴衰演变反映了自然作用和人类活动的共同影响。(3)与欧美典型潮间带潮沟侧向移动为主的演变特点不同,崇明东滩的潮沟以继承性的纵向延伸(随着盐沼的向海淤涨)为主。(4)从沟口溯源而上,潮沟的宽深比有明显的减小趋势(从大于340减小为小于18),潮沟的深度有先增大而后减小的趋势。本研究实例表明:与传统手段相比,3S技术是进行大空间尺度和长时间尺度潮间带湿地潮沟形态和演变定量研究的更有效方法。Tidal trenchs are important channel for material transport and water energy exchange in the intertidal zone. In this study, TM and ETM remote sensing （RS） images of 1994, 2000 and 2009 and GIS technology were used to define the plane morphology and calculate the length and density of the tidal trenches; RTK-GPS was used to make in situ measurements of topography for determining a typical tidal trench development hight, width, depth, width-depth ratio and longitudinal variation of the cross-section area; and GIS was used to establish the DEM model of the trench. The results show that （1） in the eastern Chongming tidal flat, tidal trenches are developed mainly in the salt marsh, and the northern and middle parts of the tidal flat are dominated by single and slightly curved ones, whereas the southern part by dendritic ones; （2） the total length and density of the tidal trenches in 1994 were 30.9 km and 717 m/km2 respectively, they decreased to 11.1 km and 459 m/km^2 in 2000 because of reclamation of the upper salt marsh and increased to 31.8 km and 981 m/km^2 in 2009 due to seaward silting of the salt marsh, which reflect the impacts of natural action and human activities on the flat; （3） not like the typical evolutionary feature of lateral movement in Europe and America, the evolution of the tidal trenches in the eastern Chongming tidal flat is mainly characterized by successive longitudinal extension （with the seaward silting of the salt marsh）; （4） from the mouth of the tidal trenches upward, the ratio of width to depth decreased from 〉340 to 〈18, and the depth first increased and then decreased. This study shows that 3S technology has advantages over traditional methods in quantitative study of large spatial and temporal scale evolution of tidal trenches.

关 键 词：潮沟 3S技术 崇明东滩 

分 类 号：P737[天文地球—海洋地质]