杭州湾近30年海岸线与海岸湿地变迁分析

Analysis on Coastline and Coastal Wetland Changes in the Hangzhou Bay in Recent 30 Years

本文以1990年以来杭州湾6个时相的Landsat ETM遥感影像为主要信息,在野外调查的基础上,通过目视解译提取杭州湾多时相海岸线以及自然湿地、人工湿地等专题要素信息,并运用马尔科夫转移矩阵分析各要素的演变规律。研究结果表明:(1)1990—2017年杭州湾的海岸线变化具有向海扩张和向陆缩减两种形式,其中,北岸近30年几乎无变化,而南岸变化较大,以向海扩张为主;(2)1990—2017年海岸线总体长度从1990年的400.4 km下降到2017年的388.4 km,其中自然岸线下降幅度大,从112.5 km下降至66.6 km,而人工岸线则从287.9 km增长至321.8 km。(3)近30年杭州湾海岸湿地的演化特点是由于填海造陆等人类活动,该区域的人工湿地面积迅速增长,从1990年的141.7 km^2增长至2017年的1221.5 km^2,而自然湿地面积则从1990年的568.9 km^2下降至2017年的230.9 km^2,人工湿地除了围垦区域,其他主要是从沿海滩涂演化而来,沿海滩涂主要转化为建设用地,因此,合理调控人类活动是改善杭州湾区域湿地现状的根本途径。

Taking the Hangzhou Bay since 1990 when the Landsat ETM remote sensing images as the main information,on the basis of field investigation,through visual interpretation from the Gulf of Hangzhou coastline and multitemporal natural wetland and artificial wetland thematic information,and by using the Markoff transfer matrix analysis of the evolution of the various elements of the law.The results showed that:(1)1990-2017 in the Gulf of Hangzhou coastline change with seaward expansion and reduction in two forms,to land the north for nearly 30 years,almost no change,while the south bank changes greatly,to seaward expansion.(2)1990-2017 coastline total length from 400.4 km in 1990 dropped to 388.4 km in 2017,in which the natural shoreline is greatly reduced,decreased from 112.5 km to 66.6 km,while the artificial shoreline from 287.9 km to 321.8 km growth.(3)the evolution characteristics of nearly 30 years of coastal wetlands in Hangzhou Bay is due to land reclamation and other human activities,the area of the artificial wetland area increased rapidly,from 141.7 km2 in 1990 to 2017 the growth of 1221.5 km2,and the natural wetland decreased from 568.9 in 2017 to km2 in 1990230.9 km2,in addition to the artificial wetland reclamation area.The other is mainly from the coastal beach evolved,coastal beach mainly converted to construction land,so the reasonable regulation of human activities is the fundamental way to improve the status of the wetland in Hangzhou Bay region.