The Dynamical Influences of Low-Level Shear and Lifting Condensation Level on Supercell Tornadoes

摘要本研究旨在将涡度分解技术纳入数值模式，以确定垂直涡度的来源及其强化机制，特别是侧重于了解环境参数和外流/上升气流定位之间的联系，与近地旋转的发展和强化有关。 这项研究亦会就雷达资料作出气候摘要。 将制定支持性观察结果，以证实建模研究的结果。 这项研究提供了一个管道，显着推进我们的理解涡度动力学和质量平衡的超级单体雷暴环境。 这项研究将提供详细的知识，时空分布的涡度源，汇和通量在强烈的风暴。 Rotunno（1988）应用先前的变革性研究来确定中气旋附近的流入和流出之间的“平衡”，这可能是开创性的，因为它提供了一个框架来确定径向质量通量（流入与流出）的理想平衡关系，特别是在低层。 这项工作也可以为热带气旋、边界层和一般湍流动力学提供重要贡献。 本文提出的涡度跟踪方法可以更好地解释高阶能量级联向主导相干结构的演化。 更广泛的影响这项研究有可能进一步改善龙卷风预报和预警程序，通过改善预警的准备时间和降低误报率。 超越各种环境参数之间的简单相关性，以更面向过程的超级单体雷暴动力学概念模型在整个科学研究领域具有更广泛的影响。 研究人员将使用会议报告和同行评审的出版物作为向天气预报界传播结果的主要手段。 这项研究包括一项计划，通过在德克萨斯州A M大学正在进行的本科生研究经验（REU）计划，吸引本科生。 该研究还包括通过UCAR Spark计划传播教育材料的计划。星火计划是美国国家大气研究中心（NCAR）及其管理机构大学大气研究公司（UCAR）的教育和推广计划。Spark是一个服务组织，帮助NCAR和UCAR将他们的研究和运营活动转化为科学准确，教学有效和广泛传播的教育经验和资源。此外，Spark还致力于扩大STEM劳动力的多样性。

Abstract This research seeks to incorporate a vorticity decomposition technique into a numerical model to determine how the sources of vertical vorticity and mechanisms for its intensification, particularly focused on understanding the link between environmental parameters and the outflow/updraft positioning, relate to the development and intensification of near-ground rotation. This study will also produce a climatological summary of radar data. Supporting observations will be developed to corroborate findings from the modeling study. Intellectual Merit This study provides a conduit for significantly advancing our understanding in vorticity dynamics and mass balances in supercell thunderstorm environments. This study will provide detailed knowledge of the spatiotemporal distribution of vorticity sources, sinks and fluxes within severe storms. The application of prior transformative research by Rotunno (1988) to determine a "balance" between inflow and outflow in the vicinity of the mesocyclone is potentially groundbreaking, by providing a framework for determining an ideal balance relationship for radial mass flux (inflow vs. outflow), especially at low levels. This work could also provide a significant contribution to tropical cyclone, boundary layer, and general turbulence dynamics. The evolution of upscale energy cascade into dominant coherent structure could be explained in better detail by the proposed vorticity tracking methods. Broader Impacts This research has the potential to further improve tornado forecasts and warning procedures, through improved lead-times for warnings and reduced false alarm rates. Moving beyond simple correlations between various environmental parameters to more a process-oriented conceptual model of supercell thunderstorm dynamics has broader impact across a full range of scientific fields of study. The investigators will use conference presentations and peer-reviewed publications as their primary means of disseminating results to the weather forecasting community. This study includes a plan to engage undergraduate students through an ongoing Research Experiences for Undergraduates (REU) program at Texas A&M University. The study also includes plans to disseminate educational materials through the UCAR Spark program. The Spark Program is the education and outreach program for the National Center for Atmospheric Research (NCAR) and its managing organization, the University Corporation for Atmospheric Research (UCAR). Spark is a service organization that assists NCAR and UCAR translate their research and operations activities into scientifically accurate, pedagogically effective, and broadly disseminated educational experiences and resources. In addition, Spark works to broaden the diversity within the STEM workforce.