VORTEX2: Damage Survey and Photogrammetric Analyses of Tornadoes, Mesocyclones, and Hook Echoes Observed during VORTEX II

VORTEX2：VORTEX II 期间观测到的龙卷风、中气旋和钩状回波的损害调查和摄影测量分析

• 批准号: 0757714
• 负责人: Nolan Atkins
• 金额: $ 23.83万
• 依托单位: Lyndon State College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-12-01 至 2012-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0757714&HistoricalAwards=false
• 关键词: VORTEX2; Damage; Survey; Photogrammetric; Analyses

This award is one component of a mutli-investigator effort known as the Verification of the Origins of Rotation in Tornadoes Experiment 2 (VORTEX 2). VORTEX 2 is a follow on to VORTEX 1 whose field phase was conducted during the Spring of 1994 and 1995. The VORTEX 1 advanced knowledge of the kinematic structures of tornadic and non tornadic storms and provided some hints as to the sensitivity of the evolution of supercell storms and tornadogenesis to very fine spatial scale heterogeneity. The VORTEX 2 research objectives will focus on the genesis and maintenance of tornadoes and on the structure of the near wind field of the tornado. The VORTEX 2 is being conducted in conjunction with the National Oceanic and Atmospheric Administration and it will involve an unprecedented observational network of stationary and mobile facilities that include Doppler radars, surface and upper air observations. . The Principal Investigators will perform detailed ground and aerial damage surveys and collect high-resolution photographic data of tornadic storms during the VORTEX II. This data will be combined with high-resolution, ground-based radar data to address the following three objectives. The first objective is to better understand the relationship between the tornado and its parent circulation. Specifically, the time evolution of tornado, mesocyclone, and damage intensities will be examined. Previous studies suggest both strong and weak correlations between tornado and mesocyclone strength. The causes of nonlinear surface damage patterns such as trochoidal and scalloping marks, left and right turns, and sinusoidal patterns documented in past damage survey data will also be explored. These patterns have been attributed to single or multiple vortices orbiting around the parent circulation. Surprisingly, no previous study has verified the visual characteristics of suction vortex and trochoidal marks in surface damage. Recent high-resolution mobile Doppler radar data sets have revealed intriguing single-Doppler velocity features, multi-parameter signatures, and reflectivity features such as weak echo eyes and debris rings within the hook echo of tornadic supercells. The second objective will be to superimpose damage survey and cloud photography data onto these radar features. Such an analysis will further understanding of the relationship between the visual characteristics of the tornado and attendant debris cloud, damage, and the radar-detected features within the hook echo. Finally, it has been shown that ground based Doppler radars at close range to large tornadoes are able to sample the flow within and around the tornado. The third objective is to examine the relationship between radar-detected wind speeds with wind speed estimates based on the Enhanced Fujita (EF) scale assessments. Such an analysis will verify the wind speeds associated with the various degrees of damage for a given damage indicator and potentially identify new damage indicators. The analysis will also examine the correlation of different wind intensity metrics such as highest wind gusts, duration of intense winds, time integrated wind speeds, and local accelerations with observed damage intensity. Intellectual Merit Realizing the above objectives will further understanding of the relationship between the mesocyclone, tornado, and attendant surface damage intensity and damage patterns. Superposition of photography and damage survey data onto high-resolution radar data will allow proper interpretation of intriguing features observed within the hook echo region. It is also anticipated that a better understanding of how tornadic flow creates observed damage will result from this research along with refinements to the newly adopted EF scale. Broader Impacts The research results will have important operational implications for the tornado detection and warning process. A better understanding of the relationship between the mesocyclone and tornado will be very useful in the tornado warning process. An improved understanding of the single-Doppler data within the hook echo may lead to tornadic precursors or identifiable features when the tornado is producing damage at the surface. Any modifications to the EF scale will improve the accuracy of the United States tornado climatology. The research will also expose undergraduate students to the data collection process during a major field experiment and the subsequent analysis. The work will enhance the research infrastructure at Lyndon State College (LSC) and the knowledge gained will be incorporated into many of the undergraduate classes taught at LSC.

该奖项是多方研究人员努力的一个组成部分，被称为龙卷风旋转起源实验2 （VORTEX 2）的验证。旋涡2是旋涡1的后续，旋涡1的实地阶段是在1994年和1995年春季进行的。涡旋1号提高了对龙卷风和非龙卷风风暴的运动结构的认识，并为超级单体风暴和龙卷风形成的演变对非常精细的空间尺度异质性的敏感性提供了一些线索。“漩涡2号”的研究目标将集中在龙卷风的发生和维持以及龙卷风近风场的结构上。涡旋2号正在与美国国家海洋和大气管理局联合进行，它将涉及一个前所未有的固定和移动设施观测网络，包括多普勒雷达、地面和高空观测。主要研究人员将进行详细的地面和空中损害调查，并收集涡旋II期间龙卷风风暴的高分辨率照片数据。这些数据将与高分辨率地面雷达数据相结合，以解决以下三个目标。第一个目标是更好地理解龙卷风与其母体环流之间的关系。具体地说，龙卷风、中气旋的时间演变和破坏强度将被检查。以前的研究表明，龙卷风和中气旋强度之间有强有弱的相关性。非线性表面损伤模式的原因，如菱形和扇形痕迹，左和右转弯，以及在过去的损伤调查数据中记录的正弦模式也将被探讨。这些模式归因于围绕母体环流运行的单个或多个漩涡。令人惊讶的是，之前的研究并没有验证表面损伤中吸力涡和齿形痕迹的视觉特征。最近的高分辨率移动多普勒雷达数据集揭示了有趣的单多普勒速度特征、多参数特征和反射率特征，如龙卷风超级单体钩回波中的弱回波眼和碎片环。第二个目标是将损害调查和云摄影数据叠加到这些雷达特征上。这样的分析将进一步理解龙卷风的视觉特征和伴随的碎片云、损害与雷达探测到的钩回波特征之间的关系。最后，研究表明，地面多普勒雷达在大型龙卷风的近距离上能够对龙卷风内部和周围的气流进行采样。第三个目标是检验雷达探测到的风速与基于增强藤田（EF）尺度评估的风速估计之间的关系。这种分析将验证风速与给定损害指标的不同程度的损害有关，并可能确定新的损害指标。分析还将检查不同风强度指标的相关性，如最高阵风、强风持续时间、时间综合风速和观测到的破坏强度的当地加速度。实现上述目标将进一步理解中气旋、龙卷风及其伴随的地表破坏强度和破坏模式之间的关系。将照片和损害调查数据叠加到高分辨率雷达数据上，可以正确解释钩回波区域内观察到的有趣特征。我们还预计，通过这项研究以及对新采用的EF尺度的改进，将更好地了解龙卷风流动如何造成观测到的损害。研究结果将对龙卷风探测和预警过程产生重要的业务影响。更好地了解中气旋和龙卷风之间的关系将对龙卷风预警过程非常有用。对钩回波内的单多普勒数据的进一步了解可能会导致龙卷风前兆或龙卷风在地面造成破坏时的可识别特征。对EF尺度的任何修改都将提高美国龙卷风气候学的准确性。该研究还将使本科生在一个主要的实地实验和随后的分析中接触数据收集过程。这项工作将加强林登州立学院（LSC）的研究基础设施，所获得的知识将被纳入LSC的许多本科课程。