1989—2021年粤港澳大湾区海岸线变迁及土地利用变化

    Variations of shoreline and land use in Guangdong-Hong Kong-Macao Greater Bay Area from 1989 to 2021

    • 摘要: 利用1989—2021年7期Landsat TM/Sentinel-2 MSI遥感影像数据,借助Google Earth Engine(GEE)平台,使用改进归一化差异水体指数(Modified Normalized Difference Water Index,MNDWI)、Canny边缘检测算法、遥感解译分类方法等,完成了粤港澳大湾区7期海岸线信息的提取,并从海岸线长度、变化强度、岸线多样性、海岸带陆域面积变化以及海岸带土地利用变化等方面分析了海岸线时空变化特征和驱动因素。分析结果表明:①1989—2021年大湾区海岸线长度持续增加,岸线变化强度具有阶段性,2004年以前岸线增长缓慢,之后岸线增长较快,2004—2009年为岸线增长高峰期;②研究时期内,大湾区各个区域内的岸线都发生了一定的变化,其中珠海、香港、深圳、澳门岸线变化最强烈,其他地区相对稳定;③研究区内岸线类型变化明显,人工岸线逐渐取代自然岸线成为海岸线的主体,人工岸线增长达651.17 km,增幅较高,自然岸线减少407.89 km;④大湾区围海造地面积显著增加,增长速率较快,岸带土地利用类型由林地、草地、水域等大幅度转向为建设用地、养殖用地;⑤围海养殖、港口码头和填海造地等人为活动是大湾区海岸线发生变化的主要原因,自然环境条件、人为活动是岸线演变的重要驱动力。

       

      Abstract: Using 7 periods of the Landsat TM/Sentinel-2 MSI remote sensing image data from 1989 to 2021 with the help of Google Earth Engine (GEE) platform, we extracted 7 periods of shoreline information from Guangdong-Hong Kong-Macao Greater Bay Area using the Modified Normalized Difference Water Index (MNDWI), Canny edge detection algorithm, and remote sensing interpretation classification method. The spatial and temporal characteristics and drivers of shoreline evolution were analyzed in terms of shoreline length, intensity of change, shoreline diversity, shoreline land area change, and shoreline land use change. The results show that: ① The shoreline length of the Greater Bay Area continued to increase from 1989 to 2021, with the total increase of 243.28 km. The variation intensity of shoreline evolution was in phase: slow growth before 2004, and fast growth after 2004 during which 2004—2009 was the fastest period. ② The shorelines in each region of the Greater Bay Area varied to some extents, of which Zhuhai, Hong Kong, Shenzhen and Macao had the greatest shoreline changes while other regions were relatively stable. ③ From 1989 to 2021, the shoreline types changed significantly as artificial shorelines grew notably, which gradually replaced the natural shorelines as the main body of shorelines. The artificial shorelines were increased by 651.17 km in total at the high rate of 172.21%, while the natural shorelines were decreased by 407.89 km. ④ During the study period, the area of land was extended significantly in the Greater Bay Area by 492.80 km2 with a fast growth rate of 15.4 km2/a, and the type of land use in the shore zone shifted remarkably from forest land, grassland, and water to construction land and farming land. ⑤ Human activities such as sea-farming, port construction, and land reclamation were the main causes of shoreline changes in the Greater Bay Area; and the natural environmental conditions and anthropogenic activities were the important drivers of shoreline evolution in the Greater Bay Area.

       

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