Abstract:To study the causes for rapid weakening and dissipation of Typhoon Bavi (No.2008) after its landfall in the north, in this study a numerical simulation is carried out with the non-hydrostatic mesoscale model WRF, and the simulated results are verified by the observation data. Furthermore, based on the high-resolution simulation results, the changes of the weather circulation background, ambient field and structural characteristics of Typhoon Bavi before and after its landfall are analyzed. The results indicate that “Bavi” was guided by the southwest airflow ahead of the mid-latitude westerly trough, and was located on the right side of the upper-level jet entrance area before its landfall. The divergence field at the upper level was conducive to maintaining the typhoon circulation. However, after its landfall, the intrusion of dry and cold air into the center of typhoon and the strong vertical wind shear were the main reasons for its loss in structure features and rapid weakening. After its landfall, the upper-level jet on the north side of typhoon decreased and the upper-level divergence weakened. Under such unfavorable upper-level circulation conditions, on the one hand, the strong vertical wind shear, especially from middle to high levels, increased the dispersion of warm air from the high-level warm core, which made the heat unable to concentrate and destroyed the upper warm core structure. On the other hand, the sinking cold air invaded the center of typhoon from the low level on the northwest side, and the vertical structure of “Bavi” was destroyed, then the height of warm core decreased and tilted to the northeast, so “Bavi” dissipated rapidly after its gradual loss of structure features. At the same time, insufficient water vapor supply after the landfall of “Bavi” was not good for its maintenance.