Tropical Cyclogenesis via Non-Axisymmetric Upscale Energy Cascade and Its Disruption by Vertical Shear

该项目涉及三个途径的热带气旋发生和发展的研究。PI和他的团队之前的工作促进了对涡旋的轴对称的理解，其中平均涡旋的加强以牺牲小尺度涡度异常为代价，使用一个相当简单的模式通过一个高尺度的能量级联过程。作为调查的第一条途径，PI将在各种初始条件下使用更现实的三维云分辨模式来进一步探索该理论的有效性。第二个途径是检查和确定高端能源级联中断的条件。如果一个正压涡旋从它的旋转轴倾斜，它可能会也可能不会回到它的直立位置(对齐)，并扰乱高档能量级联。这项工作试图确定使有限Rossby数的涡能抵抗垂直剪切的不利影响的条件。第三条途径是利用1991年进行的热带气旋现场试验的机载多普勒雷达数据来检验这一理论。这部分工作将与人力资源开发的Frank Mark和Paul Reasor博士以及纽约州立大学奥尔巴尼分校的Lance Bosart教授合作完成。这项研究的结果可能会加深对热带气旋发生的了解，并改善对热带气旋强度的预测。

This project involves studies of tropical cyclogenesis and development along three avenues. Previous work by the PI and his group advanced the understanding of the axisymmetrization for vortices where the mean vortex intensifies at the expense of the small-scale vorticity anomalies through an upscale energy cascade process using a fairly simple model. As the first avenue of investigation, the PI will further explore the validity of the theory using a more realistic three-dimensional cloud-resolving model under various initial conditions. The second avenue is to examine and determine the conditions for the disruptions of the upscale energy cascade. If a barotropic vortex is tilted from its rotation axis, it may or may not return to its upright position (alignment) and disrupt the upscale energy cascade. This work seeks to determine the conditions that enable a finite Rossby number vortex to resist the adverse effects of vertical shear. The third avenue will be the testing of the theory using the airborne Doppler-radar data from a tropical cyclone field experiment done in 1991. This part of the work will be done in collaboration with Drs. Frank Mark and Paul Reasor of HRD and Prof. Lance Bosart of SUNY/Albany. The results of this project have the potential to enhance the understanding of tropical cyclogenesis and to improve the prediction of tropical cyclone intensity.