Observational and numerical study on roles of convective activity in tropical cyclone formation and rapid intensification

再分析资料发现，热带气旋快速加强前形成了较强的低层气旋性环流。通过对热带气旋降水周期变化的数值模拟，阐明了热带气旋降水的周期行为是由雨带的形成和传播引起的，雨带的强度和次生环流的变化导致了热带气旋降水的周期变化。结果表明，较高分辨率的模拟是重现快速强化的关键。

It is found strong low-level cyclonic circulation is formed before rapid intensification of tropical cyclone from reanalysis data. Through numerical simulations on periodic variation of tropical cyclone precipitation, we clarify the periodic behavior is caused by rainband formation and propagation, which leads to the intensity and secondary circulation variation. It is indicated higher resolution simulation is key factor for reproducing rapid intensification.