利用高分辨率粒度和孢粉分析定量重建湛江地区5000年来的古台风和古气候

Typhoon is one of the most serious major natural disasters in the southeast coastal area of China. In western part of Guangdong, typhoon landing is extremely frequent, often inflicting heavy losses on local fisheries, aquaculture and agriculture. However, geological research on high resolution and millennial-scale typhoon records in southeast coastal zones of China is still rare. Currently we still know little about centennial-scale and millennial-scale frequency pattern of local super typhoon landing. The relationship between Holocene typhoon activities and climate change (especially annual mean temperature) is still a subject of considerable controversy. To enhance our understanding of long-time scale relationship between typhoon activities and climate change, we apply for funding on this research proposal. In this proposal, we drilled a core in an enclosed maar lake close to the shoreline in western coastal zones of Guangdong. Sediment samples from this core will be dated using 137Cs/210Pb and AMS-14C methods to establish a high resolution chronological framework back to mid-Holocene. Very-high-resolution grain size analysis at 2mm per sample were proposed to extracted paleo-typhoon information, so as to achieve the first objective of reconstructing a high-resolution time series of typhoon surges occurred in western Guangdong since mid-Holocene. Pollen analysis (1cm per sample) and quantitative paleoclimate reconstruction based on transfer function, MAT and module-inverse method were also proposed. The project will reveal the frequency patterns of local typhoon landing, and will be possible to enhance our understanding of long-time scale relationship between typhoon activities and climate change. The project will provide important information for future typhoon risk assessment, thus has very important significance to the development of local agriculture, fishery and aquaculture, to the planning and construction of infrastructures.

台风是我国东南沿海地区最主要的自然灾害之一。目前华南地区全新世古台风研究极少，强台风灾害频率及其与全球气候变化（特别是气温变化）的关系尚不清楚，认识上存在分歧。在全球变暖的大背景下，低纬地区强台风灾害频率会如何变化？为推进对这一问题的认识，本课题瞄准古台风和古气候地质记录，利用在湛江近海封闭湖泊（湖光岩）钻探获得的沉积物柱样，以210Pb/137Cs、AMS-14C测年手段建立精准年代框架，开展超高分辨率的粒度分析（间距0.2cm，1-2年分辨率）和孢粉分析（间距1cm）。借助粒度端元模型重建5000年来湛江地区强台风活动历史，揭示其中长期变化规律；借助孢粉-气候转换函数和现代类比等多种方法定量重建该地区5000年来年均温、年降雨量等古气候参数，并结合前人在该湖泊获得的丰富研究成果，分析区域强台风灾害与气候变化之间的耦合关系，为强台风灾害风险评估和沿海地区工农业生及基础设施规划提供新依据。