基于多年遥感数据分析长江河口海岸带湿地变化及其驱动因子

发布时间：2018-12-06 08:13

【摘要】：研究河口海岸带湿地长时间演变对湿地保护管理和海岸带资源评估具有重要意义.本文获取长江口1979—2015年10景Landsat-MSS/TM/OLI影像和2015年13景GF1-PMS高空间分辨率数据,对比两个典型实验区分类算法,选用最优的决策树算法应用到长江口Landsat影像中,得到沿岸湿地要素近40年的面积变化情况.研究表明,2015年长江河口海岸带湿地总面积为4725 km2,自然湿地占63.5%,人工湿地占21.2%,湿地总面积相比1979年增加了662 km2,自然湿地面积减少了163 km2,而人工湿地面积增加了766 km2.长江口自然湿地面积在1979—2000年减少幅度较大,2000年后由于保护管理加强而减少幅度变小;人工湿地和建筑面积增加较为明显,主要是由于大型水库的修建和人工鱼塘开发及港口建设.湿地总的变化趋势为河口区不断淤积,自然湿地转变为人工湿地,人工湿地转变为建筑用地等非湿地;其中,滩涂面积减少283 km2,水库、养殖鱼塘和水稻田面积分别增加了92、355和319 km2,主要发生在崇明东滩和启东沿岸;非湿地中建筑用地面积增加154 km2,灌木草场面积减少147 km2,主要发生在上海和启东沿岸.同时比较分析长江口3个区域湿地驱动因子发现,北岸启东沿岸和南岸南汇东滩湿地因经济快速发展和港口水利工程修建,以及过度开垦滩涂等自然湿地使人工湿地增加明显;而长江上游径流量、区域降水和海平面上涨等自然因素控制着中支河道区(如崇明东滩)自然湿地的变化.
[Abstract]:It is of great significance to study the long-term evolution of estuarine and coastal wetland for wetland conservation management and coastal zone resource evaluation. In this paper, 10 Landsat-MSS/TM/OLI images of Changjiang Estuary from 1979 to 2015 and 13 high spatial resolution data of GF1-PMS from 2015 are obtained. The classification algorithms of two typical experimental areas are compared, and the optimal decision tree algorithm is applied to the Landsat image of Changjiang Estuary. The area changes of coastal wetland elements in the past 40 years were obtained. The study shows that the total area of wetland in the coastal zone of the Yangtze River estuary is 4725 km2, in 2015, 63.5% of the wetland is natural wetland, and 21.2% of the constructed wetland in 2015. Compared with 1979, the total area of wetland increased by 662 km2, and the area of natural wetland decreased by 163 km2,. The area of constructed wetland increased by 766 km2.. The natural wetland area of the Yangtze River Estuary decreased greatly in 1979-2000, and became smaller after 2000 due to the strengthening of protection and management. The increase of constructed wetland and building area is mainly due to the construction of large reservoirs and the development of artificial fish ponds and port construction. The total change trend of wetland is that the river mouth area is deposited continuously, the natural wetland is transformed into artificial wetland, and the constructed wetland is transformed into non-wetland such as construction land. Among them, the area of tidal flat decreased by 283 km2, and the area of cultured fish ponds and paddy fields increased by 92355 and 319 km2, respectively, mainly occurred in Chongming Dongtan and Qidong coastal areas. The area of construction land increased 154 km2, shrub grassland area decreased 147 km2, mainly occurred in Shanghai and Qidong coast. At the same time, by comparing and analyzing the three driving factors of wetland in Yangtze Estuary, it is found that the constructed wetland is increased obviously due to the rapid economic development and the construction of port water conservancy project along the north coast of Qidong coast and the south coast of Nanhui Dongtan wetland, as well as the excessive reclamation of tidal flat and other natural wetlands. Natural factors such as runoff, regional precipitation and sea level rise in the upper reaches of the Yangtze River control the changes of natural wetlands in the middle branch river channel area (such as Chongming Dongtan).
【作者单位】：浙江大学海洋学院海岛海岸研究所;浙江工商大学区域生态环境与空间信息技术研究所;
【基金】：国家自然科学基金(No.41271417,41471346) 高分重大专项子课题(No.05-Y30B02-9001-13/15-4)~~
【分类号】：X37;X87

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