Vortex Alignment during the Rapid Intensification of the Simulated Typhoon Rammasun (2014) in Moderate Vertical Shear

Tropical cyclone (TC) intensification under sheared environmental conditions has garnered significant attention in recent studies. The alignment of TC vortices in the vertical is recognized as a critical factor in the rapid intensification process. However, the mechanisms responsible for vortex alignment remain elusive. In this study, we utilize the high-resolution simulation of Super Typhoon Rammasun (2014) to investigate the evolution of vertical tilt, with a specific focus on the role of asymmetric convection. Our results reveal a structural transition from a misaligned vortex before the onset of rapid intensification to an aligned structure afterward. It is found that the diabatic heating, driven by the asymmetric convection, directly shifts the vortex centers vertically and horizontally through generating positive PV tendencies. This diabatic modulation plays a pivotal role in counteracting the steering effect and offseting the vertical tilt. We also demonstrate that asymmetric convection propagates from the downshear to the upshear quadrant, significantly improving the efficiency of vertical tilt reduction. Our findings highlight the importance of the direct effect of diabatic heating on the tilt reduction of the simulated TC. This study enhances our understanding of TC intensification processes in sheared environments, shedding light on the complex interactions that drive structural changes in TCs.