Collaborative Research: Improving Our Understanding of Supercells from Convection Initiation to Tornadogenesis via Innovative Observations, Simulations, and Analysis Techniques

合作研究：通过创新的观测、模拟和分析技术提高我们对超级单体从对流引发到龙卷风发生的理解

• 批准号: 2150793
• 负责人: Conrad Ziegler
• 金额: $ 6.28万
• 依托单位: University of Oklahoma Norman Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2150793&HistoricalAwards=false
• 关键词: Collaborative; Research; Improving; Our; Understanding

Decades of study of supercell thunderstorms and tornadoes have resulted in better forecasts, better warnings, and increased public safety. However, despite this progress, there are still fundamental questions about tornado formation and the initiation of storms in environments that are conducive for tornadoes. This project will use new observations and new analysis techniques to uncover answers about the origin of tornado rotation and whether surface friction is an important factor, and how wind changes with altitude affect the initial development of thunderstorms. The results of the research may provide forecasters with more clues to why some storms form tornadoes while others do not within the same environment. The researchers also plan to contribute to public understanding of science through various outreach mechanisms, and will train multiple graduate students.This project focuses on a range of questions related to supercell thunderstorms, from initiation to tornado formation. The tornado-related research is guided by three core questions: 1) How important is baroclinically generated vorticity to the development of tornadoes, 2) Is the underlying surface a critical vorticity source for tornadoes, and 3) Why do supercell storms in similar environments often behave so differently? To address these questions, the research team will interrogate a number of well-observed tornadic storms from the VORTEX-II and TORUS field campaigns. Diabatic Lagrangian analysis (DLA) techniques will be conducted on multi-Doppler radar data and combined with swarm-sonde thermodynamic observations to create 4D thermodynamic and velocity fields, which will then be used in material circuit analyses to demonstrate the baroclinic origins of low-level circulation. Additionally, the material circuit analyses will be used on an existing 25-member ensemble of 75-m resolution numerical model simulations. New simulations will be conducted with a more generalized non-equilibrium lower boundary condition, using the two-layer model concept from the engineering community to address the frictional component of the project. New modeling simulations will also be conducted to address uncertainties related to convective initiation in shear and environmental controls on convective modes. The research team plans to target the following questions for the convective initiation (CI) work: 1) What are the variety of ways that vertical wind shear inhibits or facilitates CI, 2) How does their relative importance depend on the altitude and depth of the shear, and on the characteristics of the airmass boundary involved in CI, and 3) To what extent do the characteristics of an airmass boundary, such as its horizontal temperature gradient, depth, and forward speed relative to the environmental winds above the boundary, influence the organization of convective storms?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.

数十年对超级单体雷暴和龙卷风的研究带来了更好的预报、更好的预警并提高了公共安全。 然而，尽管取得了这些进展，关于龙卷风的形成和在有利于龙卷风的环境中引发风暴的基本问题仍然存在。 该项目将利用新的观测和新的分析技术来揭示龙卷风旋转的起源、表面摩擦是否是一个重要因素、以及风随高度的变化如何影响雷暴的最初发展等问题的答案。 研究结果可能为预报员提供更多线索，解释为什么有些风暴会在同一环境中形成龙卷风，而另一些风暴则不会。 研究人员还计划通过各种推广机制促进公众对科学的理解，并将培训多名研究生。该项目重点关注与超级单体雷暴相关的一系列问题，从引发到龙卷风形成。 龙卷风相关研究以三个核心问题为指导：1) 斜压产生的涡度对龙卷风的发展有多重要；2) 下垫面是否是龙卷风的关键涡度源；3) 为什么类似环境中的超级单体风暴经常发生行为如此不同？ 为了解决这些问题，研究小组将调查 VORTEX-II 和 TORUS 实地活动中大量观测到的龙卷风。 非绝热拉格朗日分析 (DLA) 技术将在多多普勒雷达数据上进行，并与集群探空仪热力学观测相结合，创建 4D 热力学和速度场，然后将其用于材料回路分析，以证明低层的斜压起源循环。 此外，材料电路分析将用于现有的 75 米分辨率数值模型模拟的 25 人集合。 新的模拟将在更广义的非平衡下边界条件下进行，使用工程界的两层模型概念来解决项目的摩擦部分。 还将进行新的建模模拟，以解决与切变中的对流引发和对流模式的环境控制相关的不确定性。 研究小组计划针对对流引发（CI）工作解决以下问题：1）垂直风切变抑制或促进 CI 的方式有哪些，2）它们的相对重要性如何取决于对流引发的高度和深度？切变，以及CI涉及的气团边界的特征，以及3）气团边界的特征，例如其水平温度梯度、深度和相对于边界上方环境风的前进速度，在多大程度上影响的组织对流风暴？该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。