Large-Scale Edge Waves Generated by Hurricane Landfall

飓风登陆产生的大规模边缘波

• 批准号: 0752059
• 负责人: Alexander Yankovsky
• 金额: $ 23.13万
• 依托单位: University South Carolina Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2012-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0752059&HistoricalAwards=false
• 关键词: Large; Scale; Edge; Waves; Generated

Intellectual merit:The hurricane-induced surge and flooding in the coastal areas is an important societal problem. Severe flooding outside the immediate landfall area and a few hours after the landfall can be caused by a freely propagating wave pulse. The cases indeed occurred in the past. The observations of the storm surge induced by Hurricane Wilma landfall on the West Coast of Florida on October 24, 2005 revealed a formation of a wave pulse as Wilma moved inland and the surge was no longer sustained by the wind forcing. The height of the wave pulse exceeded 1.5 m in de-tided sea level data, but it was somewhat obscured in the surge measurements because of its propagating during the low tide. The duration of this wave pulse was ~6 hrs and the propagation speed varied within a range of 10-25 m s-1 indicating an evolution process of the initial disturbance. The wave pulse is identified as an edge wave with large spatial and temporal scales. Such relatively short-lasting waves induced by a hurricane on the continental shelf were not reported before. Most likely, they escaped detection, because a sparse spatial resolution in the standard observational network maintained by NOAA and USGS cannot resolve their phase propagation. Instead, the previous studies were focused on lower-frequency coastally trapped waves (CTW) with periods comparable to or longer than the inertial, which were thought to be prevailing wave modes generated by tropical cyclones. This project will investigate the generation and alongshore evolution of the hurricane-induced edge waves by means of process-oriented numerical modeling. More specifically, the following questions will be addressed: - What are the most favorable conditions for the edge wave generation by a hurricane landfall? The roles of the hurricane size, strength, translation speed and trajectory, as well as the role of shelf topography, will be delineated. - What topographic forms induce the local amplification of the edge waves? The effects of large topographic variations (widening/narrowing shelf, bending coastline, etc.) and smaller features (inlets, estuaries, capes, etc.) will systematically be studied. - What are the mechanisms of the edge wave dissipation? Is the dissipation mostly related with the bottom friction or with the offshore energy radiation? Broader impacts:The results of the project will have applications to national and regional security in such areas as hazard mitigation, disaster prevention, and the development of early warning systems. The results will also be important for coastal zone management and protection, as well as for maritime operations. One graduate student will be supported by this project.

智力价值：飓风引起的沿海地区海浪和洪水是一个重要的社会问题。自由传播的波脉冲可能会在直接登陆区域之外以及登陆后几小时内造成严重洪水。这些案件确实发生在过去。对 2005 年 10 月 24 日飓风威尔玛在佛罗里达州西海岸登陆引发的风暴潮的观察显示，威尔玛向内陆移动时形成了波浪脉冲，并且风暴潮不再受到风力的维持。在去潮海平面数据中，波浪脉冲的高度超过了1.5 m，但由于其在低潮期间传播，因此在涌浪测量中有些模糊。该波脉冲的持续时间约为 6 小时，传播速度在 10-25 m s-1 范围内变化，表明初始扰动的演化过程。波脉冲被识别为具有大空间和时间尺度的边缘波。飓风在大陆架上引发的这种持续时间相对较短的波浪以前从未有过报道。最有可能的是，它们逃脱了检测，因为 NOAA 和 USGS 维护的标准观测网络中的稀疏空间分辨率无法解析它们的相位传播。相反，之前的研究主要集中在低频沿海困波（CTW），其周期与惯性相当或更长，这被认为是热带气旋产生的主要波浪模式。该项目将通过面向过程的数值模拟研究飓风引发的边缘波的产生和沿岸演化。更具体地说，将解决以下问题： - 飓风登陆时产生边缘波的最有利条件是什么？将描述飓风大小、强度、平移速度和轨迹的作用，以及陆架地形的作用。 - 哪些地形会引起边缘波的局部放大？将系统地研究大的地形变化（陆架加宽/缩小、海岸线弯曲等）和较小的特征（海湾、河口、海角等）的影响。 - 边缘波耗散的机制是什么？耗散主要与底部摩擦有关还是与近海能量辐射有关？更广泛的影响：该项目的成果将应用于国家和地区安全的减灾、灾害预防和早期预警系统开发等领域。研究结果对于沿海地区管理和保护以及海上作业也很重要。该项目将支持一名研究生。