我国东南沿海地区风暴潮规模区域分布模式及其对气候变化的响应

As a case study in the southeast coastal areas of China , theories and methods of climatology, atmospheric sciences, oceanography, statistics and numerical simulation are comprehensively used in this project to reconstruct historical records of landfall features of tropical cyclones (e.g., cyclone frequence and cyclone track), atmospheric forcing fields (e.g., atmospheric press and wind speed) and of numbers, tidal elevations and spatial distribution patterns of storm surge events over the past 60 years. Annual and decadal variations of landfall features of tropical cyclones are analyzed based on these reconstructed databank, and then multiple decadal scale phases are built according to evolution processes of landfall features of tropical cyclones during the past century. Proxies of climate change named as “climate modal” and spatial - temporal distribution patterns of storm surge scale are constructed in every decadal phases. Objectives of this project are to explore a spatiotemporal modeling method for a long term evolution of storm surge scale by integrating with the climate modal and the scale feature of storm surge, and develop a geographic distribution model of storm surge scale with the spatiotemporal consistency between evolution processes of storm surge scale and the climate modal in every phases. Comparison and analysis of climate modals and scale features of storm surge in different phases will be conducted to explore the responses of the geographic distribution pattern of storm surge scale to climate change in the southeast coastal areas of China. Relations among climate changes, landfall features of tropical cyclones and distribution patterns of storm surge scales in different phases would be revealed explicitly. On the basis of these researches, forecasts on variations of the geographical distribution pattern of storm surge scale will be presented according IPCC AR5 climate scenarios in the near future. Scientific conclusions of two key issues proposed in this project would be clarified. It would promote the innovative development on theoretical system of storm surge disasters and prediction approaches of storm surge events.

以我国东南沿海(江苏、上海、浙江、福建、广东、海南及广西)为案例研究区，通过重建近百年来热带气旋登陆特征和大气强迫场特征历史记录，以及近60年来风暴潮事件增水幅度和空间分布及发生频数的时空变化序列，建立近百年来气旋登陆特征的不同演变发展阶段。构建各个阶段气候状态代用指标“气候模态”，刻画各个阶段风暴潮“规模特征”的空间分布格局。研究基于“气候模态”与风暴潮“规模特征”时空一致性表达和集成的建模方法，建立我国东南沿海地区风暴潮规模区域分布模式。通过对各阶段“气候模态—规模特征”关系的对比分析，揭示气候变化对我国东南沿海地区风暴潮规模时空变化的影响，阐明“全球气候变化—热带气旋活动—气旋登陆特征—风暴潮地理格局”的内在联系，预测未来气候变化背景下我国东南沿海风暴潮规模地理空间分布格局的变化趋势。对两个关键科学问题形成比较明确的结论，推动风暴潮灾害理论的不断完善以及风暴潮规模预测方法的创新发展。

本项目通过重建1960-2016年中国东南沿海风暴潮增水强度数据集，构建1884-2018年登陆中国东南沿海地区热带气旋路径及大气强迫场特征数据集，分析了1884-2018年中国东南沿海的“气候态”及1960-2016年间东南沿海地区的“风暴潮规模特征”，并建立了风暴潮规模区域模式，探讨了风暴潮区域规模特征对气候变化的响应。.利用EEMD和M-K检验，将1884-2018年登陆中国东南沿海地区热带气旋变化分为九个阶段，通过对九个阶段气旋登陆位置、路径分布和源地特征等EOF分解所获得的第一主模态空间特征，刻画了该阶段的“气候态”。通过引入了风暴潮增水强度因子“非潮汐异常增水”概念，并结合风暴潮事件发生频次提出“风暴潮规模特征”ASPI 指数，分析了1960-2016年研究区风暴潮规模特征变化。研究结果表明，中国东南沿海地区风暴潮规模的变化具有明显的“极向”移动特征，空间分布特征从最早期(1960-1978年)的 -+ 纬向双极子型，转变为最后一个阶段(1996-2015年)的 -++ 纬向三极子型。从第二个阶段(1979-1995年)起，浙江中部以南沿海的风暴潮规模不断增大。.基于“气候态”和“风暴潮规模特征”分析结果，将中国东南沿海地区划分为三个主要岸段，建立了风暴潮规模区域模式并分析了其不同阶段的演变机制。通过大尺度环境因子特征—“气候态”特征—区域风暴潮规模演变模式的关联分析，阐明了区域风暴潮规模特征对气候变化的响应。分析发现，上世纪90年代中后期以来中国东南沿海风暴潮规模增强，且单次风暴潮平均规模显著增强，与全球变暖总体趋势一致，尤其是2000年代末期极端风暴潮规模出现显著增长。上世纪90年代中后期以来，我国东海沿岸风暴潮规模增强且北移，南海沿岸风暴潮规模向西集中，表明风暴潮规模区域分布空间变化与西太平洋副热带高压增强和西伸加强具有较强的关联性。