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NSFGEO-NERC: Toward a New Picture of the Multifaceted Meteotsunami

NSFGEO-NERC：迈向多面气象海啸的新图景

基本信息

批准号：
NE/R012202/1
负责人：
Victor Shrira
金额：
$ 8.06万
依托单位：
Keele University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FR012202%2F1
关键词：
NSFGEO NERC Toward New Picture

项目摘要

As awareness of the meteotsunami (MT) (tsunami-like wave of meteorological origin) threat to human life and coastal infrastructure is growing (e.g., >100/year MT events just on the Great Lakes), so is the need for understanding and forecasting it. However, knowledge acquired in the study of seismic tsunami is not readily transferable to MT research, because MT evolution is in important aspects qualitatively different: it is much more nonlinear and more strongly affected by bottom friction. Moreover, a realistic reconstruction of MT evolution is almost impossible because of the current poor spatial and temporal resolution MT observations, overwhelmingly confined to the shoreline. Therefore, the picture of the nonlinear transformation of a MT from generation to its shoreline manifestation is substantially incomplete. Since the MTs tend to disintegrate into very short (down to ~10s) pulses, even modern tidal gauges (1 min resolution) fail to capture essential features of its evolution. This fundamental knowledge gap is evident in our recently-published high-resolution MT observations off the Louisiana coast, which show a highly-complex, multi-scale non-linear disintegration of the MT wave. Together with other gaps identified in the literature, the observations strongly suggest revising of the current MT paradigm.Field experiment:A 3-year field experiment will be conducted to collect unprecedented high-resolution (up to 4 Hz) MT observations off the Louisiana coast, to capture fully the details of MT evolution. The site is a unique "natural laboratory": (i) it experiences 20-30 frontal passages per cold season (high MT probability); (ii) allows for the study of bottom-induced dissipation over a range of sedimentary types (coarse sands to mud); (iii) crucially, it is already monitored by WAVCIS (http://www.wavcis.lsu.edu/, Coastal Studies Institute, LSU), an ocean-observing system network sponsored by NOAA and BOEM. WAVCIS will be enhanced with high-resolution capabilities and five new stations located both on the coast and offshore. The observations will be organized into a public database.Modelling: The proposed work is based on the hypothesis that in a generic Proudman-resonated MT event trapped waves are also excited. Although usually less dangerous, they might represent an important part of the process, and behave as precursors to the main wave. The work focuses on the propagation stage of MT: a theoretical description of the nonlinear evolution of both free and trapped components of MT will be developed, including solitary waves, and will be validated for the real topography, and accounting for realistic bottom friction.MT warning: Data analysis and model development will be integrated into an evaluate-learn-correct cycle that will improve our representation of the process and our ability to anticipate MT events. Effective numerical models and early-warning strategies will be developed and tested. Presently, MT early-warning systems mostly rely on interpreting atmospheric data. The new high-resolution observations will be used to incorporate in this cycle elements of real-time ocean response.

随着人们对海啸（气象类海啸波）对人类生命和沿海基础设施的威胁的认识不断提高（例如，五大湖每年发生100次左右的海啸事件），对它的理解和预测也越来越有必要。然而，在地震海啸研究中获得的知识并不容易转移到MT研究中，因为MT演化在重要方面具有质的不同：它更加非线性，并且受底部摩擦的影响更大。此外，由于目前MT观测的空间和时间分辨率较差，并且绝大多数局限于海岸线，因此几乎不可能真实地重建MT演变。因此，MT从一代到其海岸线表现的非线性转换的图景基本上是不完整的。由于MTs往往分解成非常短的脉冲（低至~10s），即使是现代潮汐计（1分钟分辨率）也无法捕捉到其演变的基本特征。这种基本的知识差距在我们最近发表的路易斯安那海岸外的高分辨率MT观测中很明显，这些观测显示了MT波的高度复杂，多尺度非线性解体。结合文献中发现的其他空白，这些观察结果强烈建议修改当前的MT范式。野外实验：一项为期3年的野外实验将在路易斯安那海岸收集前所未有的高分辨率（高达4赫兹）MT观测数据，以充分捕捉MT演变的细节。该地点是一个独特的“天然实验室”：(i)每个寒冷季节经历20-30次锋面通道（高MT概率）；（ii）允许对一系列沉积类型（粗砂到泥）的底部诱导耗散进行研究；（iii）至关重要的是，它已经由WAVCIS （http://www.wavcis.lsu.edu/，路易斯安那州立大学海岸研究所）监测，这是一个由NOAA和BOEM赞助的海洋观测系统网络。WAVCIS将增强其高分辨率能力，并在沿海和海上建立五个新站点。这些观察结果将编入一个公共数据库。建模：提出的工作是基于一个假设，即在一般的普鲁德曼共振MT事件中，捕获波也被激发。虽然通常危险性较低，但它们可能代表了整个过程的重要组成部分，并作为主波的前兆。工作重点是大地电磁学的传播阶段：将对大地电磁学的自由和捕获分量的非线性演化进行理论描述，包括孤立波，并将在真实地形中进行验证，并考虑现实的底部摩擦。MT警告：数据分析和模型开发将集成到评估-学习-纠正循环中，这将提高我们对过程的表示和我们预测MT事件的能力。将开发和试验有效的数值模型和预警战略。目前，MT预警系统主要依赖于对大气数据的解释。新的高分辨率观测结果将用于将实时海洋响应元素纳入该周期。