1984—2019年江苏中部淤泥质海岸线淤蚀变化特征分析

Analysis of Erosion and Sedimentation Variation Characteristics of Muddy Coastline in Central Jiangsu from 1984 to 2019

江苏中部海岸线变迁剧烈,研究岸线的变迁对海岸带防护具有重要意义。以灌河口至方塘河口之间的岸线为研究对象,1984—2019年间每隔5年取一次Landsat卫星影像(共16景),对遥感影像进行解译,结合成像时刻的潮位和坡度推算平均大潮高潮线,获得岸线分布情况。利用端点变化率(EPR)来定量分析典型岸段灌河口—扁担河口(以侵蚀岸段为主)、扁担河口—斗龙港(侵蚀岸段与淤积岸段交汇)、斗龙港—方塘河闸(以淤积岸段为主)的海岸线净值变化特征。结果表明:①江苏中部岸线北侧主要以侵蚀为主,南侧以淤涨为主且速率较大;2004年前以射阳河口为界呈现“北蚀南淤”,随后射阳河口南侧出现岸线侵蚀,近年来侵蚀范围不断扩大的同时淤蚀交界点也不断南移;最新遥感影像数据显示,交界点现已南移至新洋港口南侧珍禽自然保护区内约9 km处;②1984—2019年灌河口—扁担河口(以侵蚀岸段为主)岸线平均每年向陆后退约10 m,斗龙港—方塘河闸(以淤积岸段为主)岸线每年向海推进约177 m。

The coastline of central Jiangsu province changes dramatically.It is of great significance to study the changes of coastline for the protection of coastline and the use of coastal resources.Taking the shoreline between Guanhe Estuary and Fangtang Estuary as the object,every 5 years from 1984 to 2019,a landscape image was taken,and 16 Landsat satellite images were obtained by using remote sensing and GIS,and the mean high water spring tide was calculated by combining the tidal level and slope at the imaging time.The change rate of end point(EPR)was used to analyze the change characteristics of shoreline net value and the reasons of shoreline transformation in typical shoreline sections of Guanhe Estuarary to Biandan Estuary(mainly the erosion shoreline section),Biandan Estuary to Doulong Port(the intersection of erosion shoreline and sedimentation shoreline),Doulong Port to Fangtang River Sluice(mainly the sedimentation shoreline section).The results show that:①Erosion is dominant in the north side of central Jiangsu coastline,while siltation is dominant in the south side of central Jiangsu coastline.Before 2004,the boundary of the Sheyang Estuary was“north erosion and south deposition”.After 2004,shoreline erosion appeared on the south side of the Sheyang Estuary.In recent years,while the erosion range has been expanding,the point of intersection of siltation and corrosion is also moving southward.The latest remote sensing images show that the junction has moved to about 9 km south of the Xinyang Port Estuary to Yancheng National Rare Bird Reserve.②From 1984 to 2019,the average shoreline retreated to the land by about 10 m per year from the Guanhe Estuary to the Bandan Estuary(mainly the erosion shoreline section),and the shoreline advanced to the sea by about 177 m per year from Doulong Port to Fangtang River Sluice(mainly the sedimentation shoreline section).