2010—2020年中国沿海主要海湾形态变化特征

为揭示近期中国沿海主要海湾形态的变化特征,基于Landsat影像提取2010年、2015年和2020年中国沿海主要海湾的空间信息,以海湾岸线类型结构、岸线开发利用程度、海湾面积、海湾形状和平面重心位移作为评价指标,分析2010—2020年中国沿海主要海湾的形态变化特征。结果表明：（1）近10年间中国沿海主要海湾岸线长度及结构变化显著,自然岸线长度和保有率下降;（2）海湾岸线开发利用程度上升,但上升速度开始放缓,大多数海湾属于中等开发程度;（3）海湾面积持续萎缩,但萎缩速度放缓,渤海海区海湾的面积萎缩幅度最大且速度最快;（4）海湾形状的变化趋势存在南北差异,北方趋于复杂,南方趋于简单,总体则趋于简单;（5）海湾平面重心在2015年后趋于稳定,位移距离减小,位移速度放缓。总的来说,海湾形态变化的主导因素是以围填海为主的人类活动,国家层面近年来实施的围填海管控政策和措施已在海湾形态变化方面初步显现成效。研究认为,应对中国沿海的海湾进行基本功能定位和划分,实施精细化分类管理,促进海湾区域“三生空间”布局优化。

Morphological changes of major gulfs along the coastof China from 2010 to 2020

Based on Landsat images, the spatial information of major gulfs along the coast of China in 2010, 2015, and 2020 were extracted to explore the morphological change characteristics. Some evaluation indexes, such as shoreline utilization degree, gulf area, gulf shape index, and gulf centroid, were used to analyze the gulfs' spatio-temporal change features in detail. The research showed that: (1) The shoreline length and structure of major gulfs changed significantly between 2010 and 2020, and the length and retention rate of the natural shorelines decreased. (2) The development and utilization degree of the gulf increased, with the increase rate gradually slowing down, and most of the gulf was moderately developed. (3) The gulf area continued to shrink, with a slow-down shrinking rate, and the gulf area in the Bohai Sea shrunk the most and the fastest. (4) The morphological change trend of the gulf is different from north to south. The north tends to be complicated, while the south to be simple. (5) After 2015, the gulf's plane center of gravity tended to be stable, the displacement distance decreased, and the displacement velocity slowed down. Human activities, such as sea reclamation, are the dominant factors leading to gulfs' morphological change. The national policies and measures for sea reclamation management and control in recent years have initially shown their effectiveness in affecting the gulf's morphology changes. The gulfs along the coast of China should be functionally positioned and divided, with refined classified management to optimize the layout of the "Ecological-Production-Living" space in the gulf areas.