Verification of the Origins of Rotation in Tornadoes 2 (VORTEX2) : Scientific Program Overview (SPO)

龙卷风旋转起源的验证 2 (VORTEX2)：科学计划概述 (SPO)

• 批准号: 0724318
• 负责人: Joshua Wurman
• 金额: $ 23.93万
• 依托单位: The Center for Severe Weather Research
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-10-01 至 2010-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0724318&HistoricalAwards=false
• 关键词: Verification; Origins; Rotation; Tornadoes; VORTEX2

The Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX) is a multi-agency field program to investigate (i) tornadogenesis, maintenance, and demise, (ii) tornado near-ground wind field, (iii) relationships among tornadoes, their parent thunderstorms, and the larger-scale environment, and (iv) numerical weather prediction of supercells and tornadoes. The second field experiment of VORTEX (VORTEX 2) is planned in the United States Great Plains region during the months of April-June, 2009-2010. It will be conducted as a two-phase experiment. A "tethered" phase, utilizing an adaptable observation network tethered to fixed observing facilities in central Oklahoma and conducted in each April and early May, will address foci related to storm-environment and storm-storm interactions, as well as numerical predictability. A "fully mobile" phase will take place in mid-May through June over a broad region of the central United States, with a focus on tornadogenesis and tornado wind fields.Results from the first VORTEX experiment (VORTEX 1), conducted in 1994-1995, advanced understanding of the kinematic similarities between tornadic and nontornadic supercell thunderstorms and the implied sensitivity of supercell evolution and tornadogenesis to fine-scale heterogeneity, both pre-storm and storm-induced. Recent improvements in National Weather Service warning statistics may be attributable in part to the application of VORTEX 1 findings pertaining to the role of the near-storm environment (e.g., enhanced low-level vertical wind shear, cloud base height, mesoscale boundaries) in determining the potential for tornado formation. Many new questions have emerged regarding the circulation sources for tornadoes, the role of downdrafts and their thermodynamics and microphysics in tornadogenesis, the relationship between tornadoes and larger scales of motion, and the relationship between tornadic winds and damage. Furthermore, technological advances that have occurred since VORTEX 1 (e.g., advances in ground-based mobile radar technology and improvements in the ability to obtain thermodynamic and microphysical observations) will allow investigators to explore aspects of tornadoes and their formation that they could not pursue in VORTEX 1. These advances have increased both the ability to resolve small spatial and temporal scales within thunderstorms and mobility while collecting these data. VORTEX 2 will take full advantage of cutting-edge remote and in situ mobile and fixed observing systems, as well as data assimilation techniques that can improve analyses by combining the dense observations with governing dynamical equations. The four foci of VORTEX2 are: (1) Tornadogenesis. Role of downdrafts in tornadogenesis; sensitivity of tornadogenesis to microphysical and thermodynamic characteristics; role of vorticity maxima along gust fronts in tornadogenesis and/or maintenance; modes for the development of significant tornadoes in supercells. (2) Near-ground wind field in tornadoes. Range of observed tornado characteristics, such as vertical, radial, and swirling velocity profiles, asymmetries, multiple vortices, and angular momentum budgets; relationships between damage and wind speed, acceleration, and duration. (3) Relationships between supercell storms and their environments. Interactions among storms that are/are not favorable for tornadogenesis; effects of environmental heterogeneity on supercells and tornadogenesis. (4) Storm-scale numerical weather prediction (NWP). Analysis and prediction of supercells, mesocyclones, and tornadoes; assessment of parameterization errors for storm-scale models and data assimilation methods for the storm scale; optimal use of observations; analysis and prediction of the pre-storm mesoscale environment. Intellectual merit: VORTEX 2 is designed to improve understanding of tornadogenesis, which ultimately will allow a better assessment of the likelihood of tornadoes in supercell thunderstorms and possibly even tornado intensity, longevity, and cyclic behavior. Moreover, VORTEX 2 is expected to improve understanding of the range of tornado structures and the relationships between tornado structure and characteristics of the parent thunderstorm. The purpose of this award is to provide for management and coordination of the VORTEX 2. Broader impacts: VORTEX 2 may lead to further improvements in tornado warning skill. It is believed that storm-scale numerical weather prediction must play a prominent role in the initiative to improve short-term forecasts of severe weather; multi-sensor and multi-scale VORTEX 2 datasets will serve as a testbed for numerical storm-scale prediction experiments. VORTEX 2 will further understanding of the relationships between tornadoes, their parent convection, and the larger-scale environment. Quantification of the actual temporal and spatial distribution of winds impacting structures will enable better engineering standards to be developed. Lastly, VORTEX 2 includes an innovative educational component in which students will participate in a series of scientific seminars presented in the field by the many participating severe storm expert PIs.

龙卷风旋转起源验证实验(VORTEX)是一个多机构的现场计划，目的是研究(I)龙卷风的发生、维持和消亡，(Ii)龙卷风近地风场，(Iii)龙卷风、其母雷暴和大尺度环境之间的关系，以及(Iv)超级单体和龙卷风的数值天气预报。第二次涡旋(涡旋2)现场试验计划于2009-2010年4-6月在美国大平原地区进行。它将分两个阶段进行。利用与俄克拉荷马州中部固定观测设施相连的适应性观测网络，在每年4月和5月初进行的“系留”阶段，将处理与风暴-环境和风暴-风暴相互作用有关的焦点，以及数字可预报性。美国中部大片地区将于5月中旬至6月出现“完全移动”阶段，重点是龙卷风发生和龙卷风风场。1994-1995年进行的第一次涡旋实验(涡旋1号)的结果，加深了对龙卷风和非龙卷风超级单体雷暴之间运动学相似性的理解，以及超级单体演化和龙卷风发生对风暴前和风暴引发的细尺度不均匀的隐含敏感性。最近国家气象局警报统计数据的改善可能部分归因于涡旋1调查结果在确定龙卷风形成可能性方面的应用，这些结果涉及近风暴环境(例如，增强的低层垂直风切变、云底高度、中尺度边界)的作用。在龙卷风的环流来源、下沉气流及其热力学和微观物理在龙卷风发生中的作用、龙卷风与更大规模的运动之间的关系以及龙卷风与损害之间的关系等方面出现了许多新的问题。此外，自涡旋1以来取得的技术进步(例如，地面移动雷达技术的进步以及获得热力学和微物理观测的能力的改进)将使研究人员能够探索龙卷风及其形成的某些方面，而这些方面是他们在涡旋1中无法追踪的。这些进步既提高了在雷暴中分辨小空间和时间尺度的能力，也提高了收集这些数据时的机动性。涡旋2将充分利用尖端的远程和现场移动和固定观测系统以及数据同化技术，这种技术可以通过将密集观测与控制动力学方程相结合来改进分析。VORTEX2的四个病灶是：(1)龙卷风发生。下沉气流在龙卷风发生中的作用；龙卷风发生对微物理和热力学特征的敏感性；沿阵风锋面的涡度极大值在龙卷风发生和/或维持中的作用；在超级单体中发生重大龙卷风的方式。(2)龙卷风的近地面风场。观测到的龙卷风特征范围，如垂直、径向和漩涡速度分布、不对称性、多涡旋和角动量收支；损害与风速、加速度和持续时间之间的关系。(3)超级单体风暴与环境的关系。有利于/不利于龙卷风发生的风暴之间的相互作用；环境异质性对超级细胞和龙卷风发生的影响。(4)风暴尺度数值天气预报(NWP)。超级单体、中气旋和龙卷风的分析和预报；风暴尺度模式和数据同化方法的参数化误差的评估；观测的最佳使用；风暴前中尺度环境的分析和预报。智力优势：涡旋2旨在提高对龙卷风发生的理解，最终将允许更好地评估超级单体雷暴中龙卷风发生的可能性，甚至可能是龙卷风的强度、寿命和循环行为。此外，涡旋2预计将增进对龙卷风结构范围以及龙卷风结构与母体雷暴特征之间关系的了解。该奖项的目的是提供对涡旋2的管理和协调。更广泛的影响：涡旋2可能导致龙卷风警报技能的进一步改进。人们认为，风暴尺度数值天气预报必须在改进短期恶劣天气预报方面发挥突出作用；多传感器和多尺度涡旋2资料集将作为风暴尺度数值预报试验的试验台。涡旋2将进一步了解龙卷风、其母对流和更大尺度环境之间的关系。量化影响结构的风的实际时间和空间分布将有助于制定更好的工程标准。最后，涡旋2包括一个创新的教育部分，学生将参加由许多参与的强风暴专家PIS在实地举办的一系列科学研讨会。