【摘要】 受全球气候变化以及人类活动的影响,河流入海水沙通量急剧减少,直接影响海域的生态系统。岸线和潮滩作为海岸带的重要组成部分,其演变趋势牵动着整个海湾生态环境的变化。本文基于数字化海岸线分析系统(Digital Shoreline Analysis System,DSAS),研究了广西北部湾茅尾海岸线的时空变化。文中建立了新遥感指数——滩涂指数(Tidal Flat Index,TFI),提取出露水面潮滩范围,并结合历史潮位数据分析茅尾海潮滩变化趋势。研究结果表明:(1)20世纪90年代至今,北部湾茅尾海岸线总体向海推进。其中,受填海造陆影响,钦江区域岸线向海推进速率由0.15 m/a提高到0.98 m/a;因潮流、波浪作用等因素,茅岭江区域岸线一直处于淤积状态,2001年前后受河流来沙减少的影响,岸线向海推进的速率发生突变。(2)由于清淤工程的实施,茅尾海潮滩在2013年后面积显著缩小,在时间和空间上剔除清淤工程影响,研究发现,茅岭江河口三角洲受河流来沙减少的影响较为明显,表现为三角洲面积减少,三角洲南侧遭受明显冲刷。更多还原

【Abstract】 Affected by global climate change and human activities, the flux of sand from rivers into the sea has decreased sharply, directly affecting the ecosystem of the sea area. Coastlines and tidal flats are important components of the coastal zone, and their evolution trends affect the changes in the ecological environment of the entire Gulf. Based on the Digital Shoreline Analysis System(DSAS), this paper studies the temporal and spatial changes of the Maowei coastline in the Beibu Gulf of Guangxi. In this paper, a new remote sensing index is established: Tidal Flat Index(TFI) extracts the range of outcropping tidal flats, and combines historical tidal level data to analyze the trend of tide flats in the Maowei Sea. The results show that:(1) From the 1990 s to the present,the Maowei coastline of Beibu Bay has generally advanced toward the sea. Among them, affected by land reclamation, the coastline advancing rate of the Qinjiang area increased from 0.15 m/a to 0.98 m/a; due to factors such as tidal currents and waves, the coastline of the Maolingjiang area has been in a state of siltation. In 2001 Affected by the decrease in the incoming sand from the river before and after, the rate at which the shoreline advances toward the sea has undergone abrupt changes.(2) Due to the implementation of the dredging project,the area of the Maowei Sea tidal flat has been significantly reduced after 2013. When the impact of the dredging project is eliminated in time and space, it can be found that the Maoling River estuary delta is significantly affected by the reduction of river sediment, The performance is that the area of the delta has decreased, and the south side of the delta has suffered obvious erosion.更多还原