【摘要】 建立长时间尺度台风序列对于预测未来超强台风的活动规律具有重要科学和实践意义。历史上影响海南岛地区的台风十分频繁,但因缺少确切而详实的记载往往无法判断其是否为超强台风,因此迫切需要寻找千百年尺度的超强台风沉积记录。本文对海南岛东北部翁田镇沿海地区进行详细野外调查,选定白石堡海岸沙丘剖面为研究对象,在该沙丘剖面中识别出风暴越岸沉积和海滩岩巨砾沉积。根据沉积学分析和动力过程分析,这两种类型沉积极有可能是由历史上的台风事件形成,形成年代可能达到距今3 400 a;将该沉积层中的海滩岩巨砾与台风"威马逊"搬运的最大海滩岩巨砾进行对比,发现形成该沉积层海滩岩巨砾的台风事件强度应比台风"威马逊"更强,表明该区域历史上超强台风的存在,这对建立千百年尺度的台风序列有很重要的意义。同时,研究区岸外珊瑚岸礁发育良好,动力分析表明礁坪宽度对于波浪消减、海岸防护具有显著作用。然而,随着海南岛珊瑚岸礁日益衰亡、风暴强度逐渐加大和海面持续上升,未来海南岛地区的海岸极端风浪危害和海岸侵蚀形式威胁正日益加大,亟待加强海南岛珊瑚岸礁保护。更多还原

【Abstract】 Identifying typhoon sequences on large time scales is of great scientific and practical significance to predict the super typhoon activities in the future. Although the high frequency of typhoon occurrence in Hainan Island in history is well known, it is difficult to determine the frequency of occurrence of the rare events like the Rammasun typhoon because of lack of detailed historical records. Here we use the sedimentary record, in combination with the information on the present-day events, i.e., the Rammasun typhoon, to define the typhoon intensity and identify the super typhoons that occurred in the past. A detailed field investigation was conducted in the coastal area near Wengtian Town, northeastern Hainan Island. We discovered storm beach-rock boulders and storm over-wash sediments interbedded within the coast dune sequence on the northeastern coast of Hainan Island. Base on laboratory and sediment dynamic analyses, we propose that the deposits were generated by super typhoon events, perhaps as early as 3 400 a BP. We find that the intensity of the typhoon that created these deposits was stronger than the Rammasun typhoon, which is of great significance to the reconstruction of typhoon sequences on millennial/centennial scales. Hydrodynamic analysis indicates that the wide reef flat in front of the beaches and coastal dunes plays a significant role in coast protection. Thus, the regional coral reef degeneration that is taking place now, together with likely intensified storms in response to climate change and future sea level rise, will become an enhanced risk of coastal erosion.更多还原