我国东南沿海热带气旋极端降水的识别及其成因研究

The torrential rain problem of tropical cyclone (hereinafter referred to as TC) is one of the important forefront TC research topics, and its current fruits focus on studying individual TC cases with TC torrential rain, which shows the lack of studies on causes of TC torrential rains especially on extreme TC rainfalls (i.e. statistically extreme strength TC torrential rains) in a particular region. Focusing on the causes of extreme TC rainfalls in Southeast China, this project will carry out researches in the future in the following three aspects: First, it is to identify extreme TC rainfalls in Southeast China. In step 1, we will partition TC precipitation from historical precipitation data in Southeast China using the Objective Synoptic Analysis Technique (OSAT)；Then, scientifically define extreme TC rainfalls, and a list of extreme TC rainfalls in order can be gained after a lot of analyses；In step 3, a corresponding list of TC cases in order for extreme TC rainfalls also can be gained. Second, diagnostic analyses of the causes of extreme TC rainfalls will be performed. For the environmental field and TC structure, by means of comparison analyses between the TC case group with extreme TC rainfalls and the TC case group with weak TC rainfalls and comprehensive diagnoses of individual TC cases with extreme TC rainfalls, one or more types of possible causes of extreme TC rainfalls can be drawn. Third, simulation studies of the causes of extreme TC rainfalls will be carried out. For each possible mechanism of extreme TC rainfalls, a suitable numerical test scheme for the WRF model will be carefully designed, and then a corresponding simulation study will be carried out. The research results of this project -- dynamics interpretations for the causes of extreme TC rainfalls in southeast China -- will provide a scientific basis for the strong TC torrential rain forecast, so as to contribute to the prevention of TC torrential rain disaster.

热带气旋(简称TC)暴雨问题是TC研究的重要前沿之一，其研究成果集中在TC暴雨个例的研究上, 缺乏专门针对特定区域TC暴雨特别是TC极端降水（即统计上达到极端强度的TC暴雨）成因的研究。本项目围绕我国东南沿海(浙江省、福建省和上海市)TC极端降水的识别及其成因，开展以下研究：一是东南沿海TC极端降水的判识。利用成熟的TC降水客观识别法识别出TC降水；再科学定义TC极端降水并判识得到按TC极端降水排名的TC个例清单。二是东南沿海TC极端降水成因的诊断。针对环境场和TC结构，采用对比分析和极端TC个例综合诊断相结合的方法，提出一种或多种TC极端降水的可能成因。三是东南沿海TC极端降水成因的数值模拟。针对可能的成因，利用WRF模式，设计合适的数值试验方案，开展相应模拟研究。本项目研究成果--东南沿海TC极端降水成因的动力学解释--将直接为强TC暴雨预报提供科学依据，从而有助于防御TC暴雨灾害。

2014-2017年，本项目开展了三个方面的研究工作：.一是开展了东南沿海、两广地区及海南岛三个区域热带气旋（TC）极端降水特征及成因研究。指出地形是形成TC极端降水地理分布特征的关键因子，同时，TC路径、强度、移速以及如南海夏季风强度等环境物理因子是极端降水的重要影响因子。.二是围绕强台风菲特极端降水成因诊断及数值模拟开展了较全面的研究，提出双台风作用是该地区TC极端降水形成的重要机制之一。.三是发展了TC路径相似的面积指数，并延伸开展登陆TC降水预报的探索研究和取得初步进展。本项目在TC极端降水成因方面的成果已陆续在探索研究中得到应用。.超额完成了以下任务或目标：（I）开展了两广地区及海南岛TC极端降水特征及成因研究；（II）延伸开展登陆TC降水预报的探索研究并取得初步进展；（III）论文总数和SCI(E)数量均超过预期目标：发表（含接受）论文19篇，其中SCI(E) 4篇，核心15篇；专著1部。另有4篇论文投稿中，其中3篇投SCI(E)期刊。.鉴于该项目延伸开展了登陆TC降水预报的探索研究并取得了初步进展，2018年任福民团队拟围绕登陆TC降水预报方向牵头申报国家自然基金重点项目，迫切希望且充满信心在基金委的持续支持下，在该方向上取得崭新的成果。