基于IDW的埕岛海域水下三角洲地形演变

Terrain Evolution of Subaqueous Delta in Chengdao Sea Area Based on IDW

为研究埕岛海域水下三角洲地形演变,利用1958—2014年间埕岛海域7个不同时期水深点的数据,采用不同插值方法开展适用性比较,确定选用反距离加权法进行数据插值,生成研究海域范围内7期水深地形图。通过栅格计算对不同时期的水深地形进行研究,分析比较了各个时期的地形特征,总结出区域内地形演变规律。研究表明,埕岛海域内整体地形呈西南高东北低走势,3~12 m等深线间水下岸坡地带地形最为复杂且变化剧烈,走河期淤积中心不断向东北方向推进,最大淤积厚度超过12 m,废弃后侵蚀中心逐步向岸移动,且后期侵蚀速率明显降低,形成了“陡-缓-陡”的地形特征。

Bathymetric data for seven different periods during 1958 to 2014 were collected to study the terrain evolution of subaqueous delta in Chengdao sea area.By comparing the applicability of different interpolation methods,this study selected the inverse distance weighted method to produce the digital elevation model(DEM),and seven depth maps were generated for the study area.Then,by using grid calculation,This work studied the depth and topography of different periods,compared the topographic characteristics,and analyzed the terrain evolution in the study area.The results showed that,1)The overall topography is high in the southwest and low in the northeast while the terrain of the offshore slope between 3 m and 12 m isobaths was strongly being changed.2)During river runs,the sedimentation center goes forward to north-east and the maximum deposition thickness was over 12 meters.3)Since the river is abandoned,the erosion center gradually moves toward the shore and finally forms the topographic characteristics of"steep to gentle to steep".