Abstract:Based on CMISS/MIMIC microwave satellite images, Tropical Cyclone Guidance Project (TCGP) dataset and NECP Final Analysis (FNL) dataset, this paper analyzes the co-variation of convection and dynamical structure during concentric eyewall process of Typhoon “Lekima”. The results come as follows: (1) Before the formation of concentric eyewall, the symmetry of Lekima's inner-core convective rainbands increases rapidly, presenting a ring-shaped inner rainband enveloping surround the eyewall. Between the ring-like rainband and the eyewall, there is a zone where downward motion and low humidity develop, resulting in the suppression of convection, which finally develops into a moat region. On the other hand, updraft and radial inflow largely develop around the ring-like rainband, which strengthen the import of absolute vorticity and benefit the development of deep convection. This rainband finally becomes the outer eyewall. (2) After the formation of the concentric eyewall, the secondary eyewall is gradually strengthened and contracted. The moat region becomes narrow and the convection suppression is enhanced there. However, the primary eyewall is weaken during the development and contraction of the secondary eyewall, resulting in the intensity decrease of “Lekima”.