基于RS与GIS的南汇东滩围垦研究

RS和GIS技术是滩涂围垦监测最经济和有效的方法之一。本文基于1983年以来多期遥感影像,解译出了不同时期人工岸线的位置,在此基础上利用GIS技术分析了近30年来南汇东滩的围垦过程及其与滩涂淤涨速率的关系。结果表明,近30年来南汇东滩的围垦过程呈现＂由慢至快＂的发展趋势,经历了＂缓慢—稳步—高速＂三个发展阶段：（1）1983～1995年年均围垦速率约1.23km2/a,圈围速率较小;（2）1995～2000年为7.95km2/a,围垦速率处于稳步增长阶段;（3）2002～2005年为35.27km2/a,是围垦速率最大的阶段。2002年以前,围垦速率与滩涂淤涨速率基本一致,2002年之后,围垦速率远大于滩涂淤涨速率。本文认为8km2/a是南汇东滩适宜的围垦速度。2002年之后南汇东滩的快速围垦并没有导致上海整体滩涂面积的减少,围垦可不囿于局部滩涂面积的稳定,以全市总体滩涂面积和湿地水平的动态平衡,可为滩涂资源开发利用提供现实选择。

Study of Tidal Flat Reclamation at Eastern Nanhui Based on RS and GIS

RS and GIS technology is one of the most economic and effective ways to monitor tidal flat reclamation.Based on remote sensing imagines acquired from 1983 to 2009,reclamation process and its relationship with tidal flat accretion rate in eastern Nanhui were analyzed in this paper.It reveals that the reclamation process can be divided into three phases based on reclamation speed：（1） the first phase,from 1983 to 1995,is a ＂slow＂ phase with reclamation speed about 1.23 km2/a;（2） the second phase,from 1995 to 2000,is a ＂stable＂ phase with reclamation speed about 7.95 km2/a;（3） the last phase,from 2002~2005,is the ＂fastest＂ phase so far with reclamation speed about 35.27 km2/a.Tidal flat reclamation speed and its horizontal accretion rate are nearly equal before 2002 in Eastern Nanhui,and 8 km2/a can be considered as an appropriate reclamation speed.The experience in Eastern Nanhui told us that although reclamation may not be confined to maintain the stability of local tidal flat area,the whole balance of tidal flats and wetlands area in Shanghai must be taken into account.