Using the Second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2) Observations and Idealized Simulations to Understand the Lifecycle of Tornadoes

继为期两年的多研究者现场数据收集活动取得成功之后，这项研究工作将集中于确定对龙卷风的发生、维持和消亡至关重要的物理过程和相互作用，这些龙卷风是以超级单体雷暴为特征的更广泛的旋转流(中气旋)。国家海洋和大气层管理局赞助的VORTEX2(龙卷风旋转起源核查)联合项目的主要目标是需要更好地了解和开发更可靠的手段，以识别和提供龙卷风形成的预警，该项目包括多平台实地活动，在严重的雷暴、龙卷风及其支持环境中提供丰富的雷达和现场热力学数据。这一努力的学术价值将取决于该研究小组在研究龙卷风发生、维持和消亡的控制以及风暴合并在影响这些过程中的潜在作用时利用这些数据的具体计划。将结合更理想化的数值模拟方法进行基于模型的数据分析和同化。本项目的具体研究目标是：(1)确定环境涡度和风暴产生的涡度在龙卷风的发生和演变中的相对作用；(2)调查龙卷风的后侧和前侧下沉气流在龙卷风的发生和演变中的作用；(3)研究次生后侧阵风锋面的起源和特征及其在龙卷风的发生和演变中的可能作用；(4)探索龙卷风如何受到其中气旋尺度环境的热力性质和环流的变化，以及上覆雷暴的强度或位置的变化的影响，以及(5)调查风暴相互作用和单体合并的动态以及它们如何影响风暴中涡度的发展。这一努力的广泛影响将取决于将物理理解和潜在的分析技术转移到业务气象学家，以便他们最终可能提供更准确的龙卷风警报和减少错误报警率，以及为学生和职业生涯早期的科学家提供培训机会，包括来自大气科学中代表性不足群体的个人。

Following on a successful two-year multi-investigator field data collection campaign, this research effort will focus on identification of physical processes and interactions pivotal to the genesis, maintenance, and demise of tornadoes developing within broader rotational flows ("mesocyclones") that characterize supercell thunderstorms. The need for improved understanding and development of more reliable means to identify and provide advance warning of tornado formation are key objectives of the joint NSF-NOAA sponsored VORTEX2 (Verification of the Origins of Rotation in Tornadoes) project, which encompassed multi-platform field activities providing a wealth of radar and in-situ thermodynamic data within severe thunderstorms, tornadoes, and their supporting environments. The intellectual merit of this effort will rest upon this research team's specific plans to exploit these data in their study of controls on tornado genesis, maintenance and demise, as well as the potential role of storm mergers in influencing these processes. Model-based data analysis and assimilation will be conducted in tandem with more idealized numerical simulation approaches. The specific research objectives to be addressed during this project are to: (1) Determine the relative roles of environmental versus storm-generated vorticity in the genesis and evolution of tornadoes (2) investigate the roles of the rear- and forward-flank downdrafts in the genesis and evolution of tornadoes, (3) examine the origin and characteristics of secondary rear-flank gust fronts and their possible role in the genesis and evolution of tornadoes, (4) explore how tornadoes are influenced by changes in the thermodynamic properties and circulation of their mesocyclone-scale surroundings, and by changes in the strength or location of the overlying parent thunderstorm updraft, and (5) to investigate the dynamics of storm interactions and cell mergers and the ways in which they can influence the development of vorticity in the storms.Broader impacts of this effort will hinge upon transfer of physical understanding and potential analysis techniques to operational meteorologists in order that they may ultimately provide more precise tornado warnings and decreased false alarm rates, as well as in providing the opportunity for training of students and early-career scientists including individuals drawn from underrepresented groups in the atmospheric sciences.