海洋中尺度涡对南海热带气旋活动的影响及其数值模拟

There are many mesoscale eddies and vigorous tropical cyclone activities in the South China Sea. The interaction between mesoscale eddies and tropical cyclone activities is proposed as a cutting-edge research topic and urgent need of disaster prevention and mitigation. The influence of mesoscale eddies on tropical cyclones from the perspective of the upper-ocean thermal state, however, received much less attention than the dynamic and thermal forcing of the tropical cyclone activities to the mesoscale eddies. Based on various observational and reanalysis datasets, the project firstly aims to reveal the impact of mesoscale eddies on the upper-ocean thermal structure of the South China Sea and the interannual variation between mesoscale eddies and the tropical cyclone formation. On this basis, quantitative diagnosis of atmospheric energy, water vapor, sea surface heat flux and oceanic vertical mixing is carried out for a number of tropical cyclone cases under the influenced of mesoscale eddies in the South China Sea. Relative importance of elements for upper-ocean thermal structure is evaluated by a series of numerical experiments using air-sea coupled model. Through the implementation of this project, it is expected to obtain the key factors and corresponding physical mechanism of the impact of mesoscale eddies on the tropical cyclone over the South China Sea, and to provide a scientific basis for an in-depth understanding of the interaction between the upper ocean thermal and dynamic processes and the tropical cyclone.

南海多中尺度涡活动且是热带气旋最活跃的海域之一，开展南海中尺度涡与热带气旋相互作用的深入研究，不仅是海洋与大气科学研究的前沿命题同时也是防灾减灾的迫切需要。前人的工作更多关注于热带气旋活动对海洋中尺度涡旋的动力、热力强迫，而从上层海洋热力状况角度考察海洋中尺度暖涡影响热带气旋的研究甚少。基于多种观测和再分析资料，本项目拟揭示中尺度涡对南海上层海洋热力结构的影响及与热带气旋生成的年际变化关系。在此基础上，对多个受中尺度涡影响的南海热带气旋个例生成、加强或长时间停滞不同阶段大气能量、水汽、海表热通量以及海洋垂直混合进行定量诊断，并利用海气耦合模式研究中尺度涡上层海洋热力状况相关各要素影响热带气旋活动的相对重要性。通过本项目的实施，期望揭示南海中尺度暖涡影响热带气旋的关键要素及相应物理过程，为深入理解南海上层海洋热力、动力过程与热带气旋相互作用的物理机制提供科学依据。