海南万宁岬湾海岸海滩稳定性研究

Stability of headland bay beaches on the east coast of Hainan Island

岬湾海岸海滩的稳定性及其演变是砂质海岸研究的重要内容。基于多期遥感影像、海滩沉积物粒度分布,并采用岬湾海滩平衡形态模型(MEPBAY),分析探讨了海南岛东部万宁4个典型岬湾海岸海滩的稳定性及其模型的应用。研究表明,除东澳湾凸角处于不稳定状态,其余海岸处于静态或准静态平衡状态;岬湾海滩沉积物粒度在遮蔽段和开敞段有明显的差异,相邻海滩之间没有明显的泥沙交换,每个岬湾海滩都是相对独立的地貌单元;模型中上岬角控制点选取应考虑岛礁及水下礁坪;抛物线模型可以拓展应用于有离岸岛情况下的海湾。研究成果可为岬湾海滩的稳定性评估和管理提供科学依据。

Headland-bay beach stability and its evolution processes are significant to the study of sandy coasts.In this paper,the beach stability of four typical headland-bay beaches along Wanning coast in the east Hainan Island were analyzed based on remote sensing images over the recent 40 years and MEPBAY model developed from the parabolic bay shape model.The results show that the four headland-bay beaches are in or close to the static equilibrium except the shoreline salient of Dong-ao Bay with an unstable state;Beach sediment size distribution displays a significant difference between the sheltering and open section,and there is no significant sediment exchange between adjacent beaches and each embayed beach is a relatively independent geomorphological unit;the existence of submerged reefs and shoals cannot be ignored in selecting suitable headland control point;the parabolic bay shape model can be applied in the case of offshore islands.This study can provide a scientific basis for headland-bay stability assessment and management.