Modeling and Analysis of the Landfalling Hurricane Boundary Layer

登陆飓风边界层的建模与分析

• 批准号: 0910737
• 负责人: Karen Kosiba
• 金额: $ 51.28万
• 依托单位: The Center for Severe Weather Research
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-15 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0910737&HistoricalAwards=false
• 关键词: Modeling; Analysis; Landfalling; Hurricane; Boundary

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Prior analysis of high-resolution mobile Doppler radar observations collected during Hurricane Fran (1996) has revealed evidence of highly organized sub-kilometer scale circulations termed boundary-layer "rolls," which embody organized rotation about a horizontal axis and develop within strongly sheared winds beneath some storms. Along with the more widely recognized presence of mesovortices (identified by locally-intense spin about a vertical axis), these organized features superposed on the intense, broadly cyclonic low-level airflow within hurricanes are thought to have potential to significantly influence overall storm intensity (via vertical transports of heat, moisture and momentum) and, more locally, to influence the duration and peak intensity of strong surface winds responsible for extreme property damage and loss of life. This new research effort will allow detailed examination of an extensive archive of existing data from the NSF-supported "Doppler on Wheels" (DOW) mobile radar facility for a number of more recent hurricane landfalls. In conjunction with large-eddy simulations aimed at the computer-based numerical representation of organized features within low-level wind fields, these analyses will allow quantification of turbulence structure, intensity and resultant fluxes beneath landfalling hurricanes. Where available, ancillary observations of surface wind speeds (as from surviving anemometers) and time-tagged damage to trees and engineered structures will also be considered to better relate these novel radar observations to conditions at the earth's surface. The intellectual merit of this study rests on improved documentation and dynamical understanding of the low-level ("boundary layer") atmospheric processes involved in hurricane intensity changes at far finer spatial scales than have previously been observed, and in relating these quantities both to storm intensity/structure and characteristics of the underlying surface (e.g., land-sea contrasts, type of vegetation, concentration of built structures etc.). Broader impacts will be derived through increased understanding of turbulent low-level airflows within landfalling tropical cyclones that can be implied to forecast model improvement and more accurately tuned building codes, as well as through support for an early-career scientist drawn from an underrepresented group.

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。先前对“弗兰”飓风（1996）期间收集的高分辨率移动多普勒雷达观测数据的分析，揭示了被称为边界层“卷”的高度组织化亚千米尺度环流的证据，它体现了围绕水平轴的组织化旋转，并在一些风暴下的强切变风中发展。随着人们更广泛地认识到中涡旋的存在（通过围绕垂直轴的局部强烈旋转来识别），这些有组织的特征叠加在飓风内部强烈的、广泛的气旋性低层气流上，被认为有可能显著影响整体风暴强度（通过热量、水分和动量的垂直输送），并且在更局部的情况下，影响造成极端财产损失和生命损失的地面强风的持续时间和峰值强度。这项新的研究工作将允许对nsf支持的“车轮上的多普勒”（DOW）移动雷达设施的大量现有数据档案进行详细检查，这些数据来自最近飓风登陆的一些数据。结合以计算机为基础的低层风场有组织特征的数值表示为目标的大涡模拟，这些分析将允许对登陆飓风下的湍流结构、强度和最终通量进行量化。在可能的情况下，还将考虑对地面风速的辅助观测（如从现存的风速计）和对树木和工程结构的时间标记破坏，以便更好地将这些新的雷达观测与地球表面的情况联系起来。本研究的知识价值在于改进了文献记录和对低层（“边界层”）大气过程的动力学理解，这些过程涉及飓风强度变化的空间尺度比以前观察到的要小得多，并且将这些数量与风暴强度/结构和下垫面特征（例如，陆海对比、植被类型、建筑结构集中等）联系起来。更广泛的影响将通过增加对登陆热带气旋中的湍流低层气流的了解而产生，这可能意味着预测模型的改进和更准确地调整建筑规范，以及通过支持来自代表性不足的群体的早期职业科学家。