基于DSAS和Gabor滤波增强的海南人工岛建设对砂质岸线变化的影响分析

Influence of Hainan artificial island construction on the change of sandy shoreline based on DSAS and Gabor filter enhancement

离岸人工岛作为开发利用海洋空间资源的一种方式,影响了近岸的水动力条件,对近岸砂质岸滩稳定性造成了冲击。文中基于Landsat和高分系列影像数据,采用Canny边缘检测方法提取了海南省椰林湾海上休闲度假中心人工岛(下文称椰林湾人工岛)和日月湾人工岛2011年至2018年近岸砂质岸线数据,运用数字岸线分析系统(DSAS)对人工岛建设前后周围砂质岸线变化进行分析。选取建岛前后处于涨潮期的影像对其进行Gabor滤波增强处理,通过影像所包含的纹理信息提取人工岛建岛前后水体流态方向场数据,用于分析泥沙运移趋势。结果证明:两个人工岛建设后明显的改变了周围水体的流向,椰林湾人工岛建成后邦塘湾东段近岸砂质岸线由侵蚀转变为淤积,最大淤积速率达151.48 m/a,并在人工岛后方形成连岛沙坝;西段沿岸由淤积转变为侵蚀,最大侵蚀速率达85.13 m/a。日月湾人工岛砂质岸线由自然状态转变为淤积,"日"岛近岸最大淤积速率达到196.25 m/a,已形成连岛沙坝,"月"岛最大淤积速率为82.21 m/a。

As a way to develop and utilize marine space resources, offshore artificial island affects the hydrodynamic conditions of the nearshore and has an impact on the stability of the nearshore sandy beaches.Based on the Landsat and high-scoring series of image data, Canny edge detection method was used to extract the coastal shoreline data of the Coconut Bay Leisure Resort Center Artificial Island and the Riyuewan Artificial Island from 2011 to 2018. The DSAS system was adopted to analyze the changes in the sandy shoreline around the artificial island before and after construction. The image of the high tide period before and after the construction of the island was selected for Gabor filtering enhancement. The texture information of the water body before and after the construction of the artificial island image was used to analyze the sediment transport trend. The results show that the construction of the two artificial islands has obviously changed the flow direction of the surrounding water bodies. After the artificial island of the Coconut Bay Leisure Resort Center was completed, the sandy shoreline of the eastern bank of the Bangtang Bay was transformed from erosion to siltation, and the maximum deposition rate reached 151.48 m/a, and the island sand bar was formed behind the artificial island;the west coast changed from siltation to erosion, and the maximum erosion rate reached 85.13 m/a. The sandy shoreline of Riyuewan Artificial Island changed from natural state to siltation.The maximum siltation rate of the nearshore of the "Ri" island reached 196.25 m/a, and the island dam was formed. The maximum siltation rate of "Yue" Island was 82.21 m/a.