Improving our understanding of vorticity development in supercells through novel thermodynamic observations and an improved treatment of the near-surface layer in simulations

这项研究试图提高我们对严重的“超级单体”雷暴中发生的过程的理解，这些过程控制着近地表垂直涡度(或称“自旋”)的发展，可能增强到龙卷风强度，以及此后的演变。这个项目针对超级单体风暴的两个方面，这两个方面是出了名的难以模拟和观察：(1)浮力场及其水平梯度的影响和(2)下垫面的影响。观测和数值模拟方法是创新的，具有变革的潜力，不仅在严重风暴社区，而且在其他科学界也是如此。这项工作将解决严重风暴社区长期存在的关键需求，在风暴中获得精细的3D热力学观测？此外，私人机构亦会在当地一间非牟利博物馆设立永久展览，教育公众认识严重风暴，这将对社会作出宝贵的贡献。从历史上看，私人投资机构参与了一系列广泛的外联活动，包括K-12和公共教育，作为政府团体和媒体的科学顾问参与，以及出版可供广大受众阅读的文章。PI计划承担以下任务：1)使用伪拉格朗日漂移子对超级单体风暴进行采样；2)使用改进的湍流方法来研究摩擦产生的涡度；这两种方法都是新颖和有创意的。使用伪拉格朗日漂移体观测超级单体周围和内部边界层的3D结构，能够在风暴最危险和最关键的部分获得观测，而对观测者的安全风险最小，这是一种新颖的方法。这一新的观测工具将被用来对延伸到超级单体核心的边界层中的风和热力学特征进行准拉格朗日观测，包括在冷池中，这些冷池已经被证明对于龙卷风形成足够的近地表流向涡度至关重要。这一奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This research seeks to improve our understanding of the processes occurring within severe "supercell" thunderstorms that control the development of near-surface vertical vorticity (or "spin"), possible intensification to tornado strength, and the evolution thereafter. This project targets two aspects of supercell storms that are notoriously difficult to simulate and observe: (1) the influence of the buoyancy field and its horizontal gradients and (2) the influence of the underlying surface. The observational and numerical modeling methods are innovative and have the potential to be transformative, not only in the severe storms community, but in other scientific communities as well. This work will address a long-standing, critical need in the severe storms community, obtaining fine-scale 3D thermodynamic observations within storms? The PIs will also develop a permanent exhibit at a local, non-profit museum educating the public on severe storms, which will be a valuable contribution to the community. Historically, the PIs have been involved in a broad range of outreach activities, including K-12 and public education, the participation as science advisors for government groups and media, and publishing articles accessible to a broad audience. The PIs plan to undertake the following tasks: 1) sample supercell storms using pseudo-Lagrangian drifters and 2) use improved turbulence methods to study frictionally generated vorticity; both approaches are novel and creative. The use of pseudo-Lagrangian drifters to observe the 3D structure of the boundary layer surrounding and within supercells, capable of obtaining observations within the most dangerous and critical parts of the storm with minimal safety risks to the observer, is novel. This new observational tool will be used to obtain quasi-Lagrangian observations of wind and thermodynamic characteristics in the boundary layer extending into the core of the supercell, including in the cold pools which have been shown to be critical in developing sufficient near surface streamwise vorticity for tornadogenesis.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.