大气季节内振荡触发江淮流域热浪事件的机制研究

Heat wave (HW) event is one of extreme meteorological disasters in summer. Improving the HW prediction is necessary for disaster prevention and mitigation, which is also one of important aims for extended-range prediction in science community. Understanding HW event trigger mechanism is the foundation of improving heatwave extended-range prediction. Currently, HW study mainly focus on inter-annual to inter-decadal time scale and the HW extended-range research is lacking. Intra-seasonal variation (ISV) is the most significant atmospheric signal in extend-range time scale. Yangtze-Huaihe River Basin is the domains where HWs most frequently occur, where ISVs are significant and feature with diversity. Based on long-recorded historical datasets, this study will first recognize the relation between ISVs and HWs, and categorize the HW events according to ISV features (periodicities and propagations); then investigate the different types of ISVs impact on HW generation and identify the associated HW precursors. Finally, WRF is applied to validate the HW trigger mechanism through specific lateral boundary layer sensitive experiment design according to observational results. This study can provide theoretical and empirical foundation for extended-range prediction.

热浪是夏季较常见的极端气象灾害，提高热浪的预测能力对防灾减灾至关重要。在季节内尺度上理解热浪事件的触发机制是提高热浪延伸期预测能力的重要基础。目前有关热浪的研究多集中在年际-年代际变化尺度，季节内尺度上热浪事件的触发机理研究尚欠缺。季节内振荡是理解热浪事件季节内触发过程的最重要大气信号。江淮流域是中国东部热浪高发区，该地区大气季节内振荡的特征显著且具有多样性。本研究基于历史上的季节内热浪事件，首先揭示江淮流域热浪事件与大气季节内振荡的关联，并根据不同大气季节内振荡的特征(长\短周期和高\低纬度)对热浪事件进行归类；接着，研究大气季节内振荡对热浪事件的触发机制，辨识不同类别热浪事件发生的先兆信号；最后，利用区域模式，设计特定侧边界滤波的数值试验，模拟典型热浪事件，对季节内振荡触发热浪的物理机制进行数值验证。本研究将为提高热浪事件的延伸期预测能力提供理论基础。

项目较圆满地完成了预期研究目标，揭示了江淮流域热浪事件与大气季节内振荡的密切关联; 分析并数值验证大气季节内振荡触发江淮流域热浪事件的物理机制; 辨识季节内尺度上江淮流域热浪事件的前期先兆异常信号，并超额在区域次季节-季节预测中检验和应用。项目组成员共发表SCI论文14篇，软著3套，国家级业务应用1项。培养硕士生3名，博士生4名，博士毕业2人，硕士毕业2人，团队成员1人晋升为教授，1人晋升为助理研究员，项目负责人获得国家基金委优秀青年基金资助， 团队中3人获得国家基金委青年基金资助。