摘要

The improvedWeather Research and Forecasting model was used to simulate Typhoon Megi, which experienced rapid intensification (RI) and gradual intensification processes. The model reproduced the typhoon track and intensity in accordance with the best-track observations. Our study has shown that in small or moderate shear environments, the great latent heat released in the upper troposphere through the enhancement of convective bursts, which enhanced the upper-level warm core and caused the intensification of typhoon. During the onset of RI, strong convective cells were found gathering in downshear eyewall quadrant or the left side of shear. They also indicated an asymmetric structure in the eyewall. As Megi intensified rapidly, the strong convective activity occurred both in upshear and downshear quadrants, then the symmetrical structures developed well.