Collaborative Research: Self-Organization of Vortices as a Contributing Mechanism for Tropical Cyclogenesis

热带气旋对生命和财产构成了非常严重的威胁，并影响到全球许多地方的许多人。因此，在更好地了解它们的结构和演变方面取得的进展有可能在许多层面上直接影响社会。可以说，对热带气旋的研究可以分为三类：运动、强度变化和成因。在理解前者方面取得了进展，但在更好地理解后两个进程方面取得的进展明显较少。这项研究将涉及热带气旋成因的某些方面，并有可能大大提高有关热带气旋的科学知识和最终预测技能。成因过程尚未得到严格和普遍的定义，但大多数人会同意它包括各种事件，如从中层涡旋形成低层涡旋，以及从冷核结构形成暖核热力学结构。这项研究将集中在涡旋合并在这些过程中的作用。以前的一些研究有力地支持了这样一种观点，即多个较小的涡旋合并成一个较大的“母”涡旋是形成过程的关键部分。然而，目前，关于合并过程如何影响所产生的母涡的具体结构的细节还没有得到很好的研究或记录。通过在二维湍流中独特地应用基于概率解的概念，这项工作将探索和记录一种预测由多个合并事件形成的母涡的准确结构的方法。该方法仅基于形成母涡的较小涡旋的组合环流和能量的知识来预测母涡结构。该方法表明，与具有相同总环流的其他构型相比，某些构型的小涡将合并形成更小、更强的母涡。这是一个重要的特征，因为母涡旋维持自身并进一步增强为初始热带气旋的能力很大程度上取决于其结构。由于小尺度涡旋通常是在积雨云团内形成的，因此可以在一定程度上进行远程测量，因此这项工作的结果可能为预测哪些云团更有可能经历热带气旋生成提供了洞察。

Tropical cyclones pose a very significant threat to life and property, and affect many people in many places around the globe. Progress towards better understanding of their structure and evolution thus has the potential for directly impacting society on a number of levels. The study of tropical cyclones may arguably be separated into three categories: motion, intensity change, and genesis. Progress has been made toward understanding the former but measurably less progress has been made towards better understanding of the latter two processes. This research will address certain aspects of tropical cyclone genesis and has the potential to significantly advance scientific knowledge and ultimately predictive skills in regard to tropical cyclones. The genesis process is not yet rigorously and universally defined, but most would agree that it comprises a variety of events, such as formation of a low-level vortex from a mid-level vortex, and formation of a warm core thermodynamic structure from a cold core structure. This research will concentrate on the role of vortex merger in these processes. There have been a number of previous studies that strongly support the idea that the merger of multiple smaller vortices into a larger "parent" vortex is a key part of the genesis process. Presently, however, the details of how the merger process affects the specific structure of the resulting parent vortex have not been well studied or documented. By uniquely applying concepts based on probabilistic solutions in two dimensional turbulence, this work will explore and document a method for predicting the exact structure of a parent vortex formed by multiple merger events. The method predicts the parent vortex structure based solely on knowledge of the combined circulation and energy of the smaller vortices that formed it. The method demonstrates that certain configurations of small vortices will merge to form a smaller, more intense parent vortex than other configurations that have the same total circulation. This is an important feature since the ability of the parent vortex to maintain itself and intensify further into an incipient tropical cyclone can depend strongly on its structure. Since small-scale vortices are typically formed within clusters of cumulonimbi, and thus can be remotely measured to some degree, the results of this work might offer predictive insight into which cloud clusters have a better chance of undergoing tropical cyclogenesis.