1987-2017年莱州湾沿岸土地利用变化及其对海岸线变化的影响

[目的]阐释莱州湾沿岸土地利用变化及其对海岸线的影响,为政府以及相关部门在进行海岸线规划提供土地利用方面的数据支撑。[方法]提取莱州湾近岸1987-2017年的土地利用变化信息以及海岸线空间分布,计算土地利用程度指数,随后利用DSAS计算相邻时相海岸线各段的变化速率,通过ArcGIS软件的叠加分析工具,得到影响各个时相海岸线变化速率和海岸线长度的信息。[结果]①1987-2017年,水产养殖用地、盐场用地以及建设用地面积逐渐增加;内陆水体面积总体呈增加趋势;裸地呈减少趋势;草地和耕地则先增加后减少;林地变化不明显。②土地利用程度逐渐变强,土地利用程度强等级由零散点分布变为集中面状分布。③土地利用以围填海的形式影响海岸线的变化速率。莱州湾内部的围海和人工填海使得岸线向海推进。黄河泥沙淤积填海使得黄河三角洲处的岸线向海推进,而该处岸线的背海移动则主要受到海水影响。[结论]莱州湾沿岸土地利用变化明显,土地利用程度逐年变强。土地利用以围填海的形式影响海岸线的变化速率,使得海岸线既有向海推进又有背海移动。裸地和水产养殖用地为1987-2005年影响海岸线长度的主导因素,建设用地和裸地为2005-2017年影响海岸线长度的主导因素。

Land Use Change and Its Influence on Coastline Change Along Laizhou Bay During 1987-2017

[Objective]The land use change and its influence on coastline change along Laizhou Bay was illustrated in order to provide land use data support for the government and relevant departments in coastline planning.[Methods]The land-use and land-cover change(LUCC)information of the coastwise area of Laizhou Bay and spatial distribution of coastlines from 1987 to 2017 was extracted,and land use degree index was calculated.Then the digital shoreline analysis system(DSAS)was used to calculate the adjacent phase change rate of coastlines.By the tool of overlay in ArcGIS,the factors which influence the change rate and length of coastlines were obtained.[Results]①The area of aquaculture land,salt farm land and construction land had increased gradually from 1987 to 2017;and the area of inland water had increased on the whole;the area of bare land had decreased;and the area of grassland and cultivated land had increased and then decreased;the change of forest land had not been obvious.②The land use degree had gradually become stronger,the land use degree with strong grade had changed from scattered distribution to centralized facet distribution.③Land use had affected the change rate of coastline in the form of reclamation of the sea.The enclosed sea and artificial making grounds within Laizhou Bay had pushed the coastlines to the sea;The coastline of the Yellow River delta had been pushed to the sea by the sedimentation of the Yellow River and the backsea movement of the coastlines had mainly been affected by seawater.[Conclusion]The land use along Laizhou Bay had changed obviously,and the degree of land use had been getting stronger.Land use affected the change rate of coastline in the form of reclamation of the sea,which made the coastline both advance to the sea and move back to the sea.Bare land and aquaculture land were the leading factors influencing coastline length from 1987 to 2005,while construction land and bare land were the leading factors influencing coastline length from 2005 to 2017.