Collaborative Research: Damage Analysis and Numerical Simulation of Convectively Driven Wind Events Observed during the Bow Echo and Mesoscale Vortex Experiment (BAMEX)

合作研究：弓回波和中尺度涡实验（BAMEX）期间观测到的对流驱动风事件的损伤分析和数值模拟

• 批准号: 0233178
• 负责人: Nolan Atkins
• 金额: --
• 依托单位: Lyndon State College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-01 至 2007-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0233178&HistoricalAwards=false
• 关键词: Collaborative; Research; Damage; Analysis; Numerical

The bow echo is known as a prolific producer of severe, though primarily non-tornadic, wind damage at the ground. The generally accepted explanation for the damaging wind involves a strong surface cold pool and associated rear-inflow jet (RIJ) that descends to the ground behind the apex of the bow. Recent idealized numerical simulations and limited observations are suggesting a different model, in which damaging surface winds are also induced tens of kilometers north of the apex by low-level, meso-gamma scale (order 10 km diameter) vertical vortices. Simulations suggest that, under certain conditions, mesovortex winds can be stronger, have longer durations, and produce a larger area of significant damage than can the RIJ winds at the apex. Adequate observations to validate this new explanation have yet to be collected. Further, the generality of this damaging-wind producing mechanism has yet to be established in instances when the mesoscale environment of the bow echo is significantly inhomogeneous. Underscoring the importance of this are recent observational studies that indicate a relation between reports of damaging straight-line (and/or tornadic) winds and the interaction of a bow echo and mutually perpendicular "external" outflow boundary.The primary objectives of this research are to: (i) conduct detailed aerial and ground surveys of wind damage following bow echo events, relating the severity and scale of damage to radar-observed convective system location and structural characteristics; and (ii) perform analyses and mesoscale model simulations of bow echo events in order to investigate dependencies of damaging winds, meso-vortexgenesis, and convective system structure on the inhomogeneous mesoscale environment. The bow echo and mesoscale convective vortices (MCV) experiment (BAMEX) will provide the framework for the proposed work. BAMEX seeks to understand and improve prediction of: the meso- and cellular-scale processes, within bow-shaped mesoscale convective systems, that lead to damaging winds at the ground; and MCVs and the deep cumulus convection they often trigger. BAMEX will be conducted over a large experimental domain centered on St. Louis, Missouri, and will involve unprecedented data collection via specialized airborne and ground-based observing platforms. Post-event damage surveys, a critical component of the BAMEX dataset, will be conducted under this award and used to meet numerous BAMEX objectives beyond those to be addressed under this award.The results of this research will significantly clarify the understanding of damaging wind production in bow echoes and will illuminate where the most damaging winds are most likely to occur, with what radar-observable attributes, and under what mesoscale environmental conditions. Ultimately, results may be applied by operational forecasters to issue more timely and accurate forecasts and warnings of damaging nontornadic surface winds.

弓状回波被认为是严重的，但主要是非龙卷风，地面风破坏的多产者。 对破坏性风的普遍接受的解释涉及到一个强大的表面冷池和相关的后流入射流（RIJ），该射流下降到弓形顶点后面的地面。 最近的理想化数值模拟和有限的观测表明了一个不同的模型，在这个模型中，破坏性的地面风也是由低层、中伽马尺度（直径10公里）的垂直涡旋在顶点以北几十公里处引起的。 模拟表明，在某些条件下，中涡旋风可能比顶部的RIJ风更强、持续时间更长，并产生更大的严重破坏区域。 还需要收集足够的观察结果来证实这一新的解释。 此外，当弓形回波的中尺度环境显著不均匀时，这种破坏性风产生机制的一般性还有待建立。 最近的观察性研究强调了这一点的重要性，这些研究表明，（和/或龙卷风）风和弓形回波与相互垂直的“外部”流出边界的相互作用。本研究的主要目标是：（i）在船首回波事件发生后，对风害进行详细的空中和地面调查，将损害的严重程度和规模与雷达观测到的对流系统位置和结构特征联系起来;以及（ii）执行弓形回波事件的分析和中尺度模型模拟，以便研究破坏性风，中尺度涡旋生成，和对流系统结构。弓形回波和中尺度对流涡（MCV）实验（BAMEX）将为拟议的工作提供框架。 BAMEX旨在了解和改善对以下方面的预测：弓形中尺度对流系统内的中尺度和细胞尺度过程，这些过程导致地面的破坏性风; MCV和它们经常触发的深积云对流。 BAMEX将在以密苏里州圣路易斯为中心的一个大型实验区进行，并将通过专门的空中和地面观测平台进行前所未有的数据收集。 事件后损害调查是BAMEX数据集的一个重要组成部分，将在该奖项下进行，并用于满足BAMEX在该奖项下解决的众多目标。这项研究的结果将大大澄清对弓形回波中破坏性风力产生的理解，并将阐明最有可能发生最具破坏性的风的地方，具有哪些雷达可观测属性，以及在何种中尺度环境条件下。 最终，结果可能会被业务预报员应用，以发布更及时，更准确的预报和警告破坏性的非龙卷风地面风。