Role of Intense Convection in Sheared Tropical Cyclones

这个项目包括三个部分。首先，将对一组热带气旋的方位螺旋度分布与周围垂直风切变进行综合研究。之前对飓风邦妮的研究表明，螺旋度在方位上存在巨大的不对称性，在下切变方向上有很大的螺旋度和强烈的超级单体风暴。其目标是检验这些结果在大范围风暴中的稳健性。第二，将利用在风暴期间获得的大量航空气象和雷达数据以及投射探空仪观测资料，对飓风邦妮的演变进行详细研究。目的是了解风暴是如何在强环境切变存在的情况下保持其强度的。最后，我们将探讨螺旋度分布在热带风暴形成和下切变再形成中的作用。在陆基连续雷达的范围内，将获得一组近岸热带气旋的雷达观测。热带风暴加布里埃尔(2001年)将是研究中的一个风暴。其目的是研究在大螺旋度存在的情况下气旋内单个雷暴单体的结构和演变，以及这些单体如何影响更大范围的气旋环流。广泛的影响包括对研究生的培训，支持研究生参加会议和介绍他们的工作，以及在参考文献和会议上传播结果。研究成果将有助于更好地理解和预测飓风。作为推广工作的一部分，项目科学家和学生还将向非专业团体发表关于飓风的演讲。

This project has three parts. First, a composite study will be conducted of the azimuthal helicity distribution in a group of tropical cyclones with respect to ambient vertical wind shear. A previous study of Hurricane Bonnie showed an enormous azimuthal asymmetry in helicity, with large helicity and intense supercell-like storms in the downshear direction. The goal is to examine the robustness of these results over a wide range of storms. Second, a detailed study will be carried out concerning the evolution of Hurricane Bonnie using an extensive set of airborne meteorological and radar data, and dropsonde observations, obtained during that storm. The goal is to understand how the storm maintained its intensity in the presence of strong ambient shear. Finally, the role of the helicity distribution on the formation and downshear re-formation of tropical storms will be examined. Radar observations will be obtained for a group of near-coastal tropical cyclones within range of continuous land-based radar. Tropical Storm Gabrielle (2001) will be one storm in the study. The goal is to examine the structure and evolution of individual thunderstorm cells within the cyclone in the presence of large helicity and how such cells influence the larger-scale cyclone circulation.Broader impacts include the training of graduate students, support for graduate students to attend conferences and present their work, and dissemination of results in the refereed literature and at conferences. The research results will contribute to a greater understanding and better prediction of hurricanes. Project scientists and students will also give talks on hurricanes to lay groups as part of outreach efforts.