Collaborative Research: Supercell Left Flank Boundaries and Coherent Structures--Targeted Observations by Radars and UAS of Supercells Left-flank-Intensive Experiment (TORUS-LItE)

Supercell thunderstorms are responsible for the majority of significant tornadoes in the United States. However, not all supercells form tornadoes and the false alarm rate for tornado warnings is stubbornly high. This small field campaign will use a variety of instrumentation, including radar trucks and uncrewed aerial systems (UAS) to observe atmospheric boundaries that form in what is known as the left flank region of a supercell. The idea is that observing small scale motions and boundaries near supercells will allow us to better understand why some supercells form tornadoes while others do not. Beyond the practical operational forecasting aspect of this project, the field campaign will provide 15-20 students with the opportunity to participate in the collection of data. This award is for the Targeted Observations by Radars and UAS of Supercells Left-flank-Intensive Experiment (TORUS-LItE), an observational study of specific processes in the left flank of supercell thunderstorms and how they relate to tornadogenesis. The research team will deploy UAS, radar, sounding, and mobile Mesonet assets during a three-week period in May and June 2023 in the Great Plains to directly sample boundaries and coherent structures. The investigators believe that advancing understanding of the relationship between supercell tornadogenesis and left/forward flank boundaries and coherent structures requires cross-sectional datasets that enable characterization of the structure and evolution of these boundaries and associated coherent structures in the context of supercell/mesocyclone strength and proximate evolution of near-surface rotation. The science questions to be studied are: A) How often are left/forward-flank boundaries coincident with enhanced vorticity and how does the magnitude of this vorticity relate to the characteristics of the associated boundaries and environmental/ambient state? B) Do the characteristics of streamwise vorticity currents (SVCs) and associated boundaries attendant to tornadic storms differ significantly from those associated with non-tornadic storms? C) Can the dense-side airmasses of left-flank boundaries be characterized as density currents and are SVCs the attendant Kelvin-Helmholtz (KH) billows?This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

超级电池雷暴负责美国的大多数龙卷风。 但是，并非所有超级电池都形成龙卷风，龙卷风警告的错误警报速度很高。 这项小型田野运动将使用各种仪器，包括雷达卡车和未螺旋的空中系统（UAS），以观察大气边界形成的大气边界，在所谓的超级电池的左翼区域中形成。 这个想法是，在超级电池附近观察小规模的动作和边界将使我们能够更好地理解为什么有些超级电池会形成龙卷风，而另一些则没有。 除了该项目的实际操作预测方面外，现场活动还将为15-20名学生提供参与数据收集的机会。 该奖项是针对超级单元左翼强度实验（torus-lite）的雷达和UAS的靶向观察，这是对超级雷暴左侧特定过程的观察性研究，以及它们与龙卷风的关系。 研究小组将在2023年5月和2023年6月在大平原上部署UAS，雷达，声音和移动中性资产资产，以直接采样边界和相干结构。 研究人员认为，对超细胞龙卷风发生与左前侧面边界和相干结构之间的关系提高理解需要横截面数据集，以使这些边界的结构和相关结构在超级/中粒/中旋转强度的强度和近距离旋转的进化中表征结构和相关结构。 要研究的科学问题是：a）左/前向持续边界与增强的涡度相吻合的频率以及这种涡度的大小与相关边界和环境/环境状态的特征有何关系？ b）流向涡度电流（SVC）和龙卷风风暴的相关边界的特征是否与与非龙卷风风暴相关的风暴有很大差异？ c）左轮边界的致密空气质量是否被描述为密度电流，而SVC是随之而来的Kelvin-Helmholtz（KH）滚动器？该奖项反映了NSF的法定任务，并被认为是通过该基金会的知识分子功能和广泛影响来评估Criteria的智力功能和广泛影响。