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

随着人们对流星海啸(MT)(类似海啸的气象波)对人类生命和沿海基础设施的威胁的认识日益增强(例如，仅在五大湖发生的100/年MT事件)，了解和预测它的必要性也越来越大。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的演化在重要方面有质的不同：它更具非线性，受海底摩擦的影响更大。此外，由于目前MT观测的空间和时间分辨率很差，绝大多数局限于海岸线，因此几乎不可能现实地重建MT演化。因此，MT从生成到其海岸线表现的非线性转换的图像基本上是不完整的。由于MTS倾向于分解成非常短(低至~10s)的脉冲，即使是现代潮汐测量仪(1分钟分辨率)也无法捕捉到其演化的基本特征。这一基本知识差距在我们最近发表的路易斯安那州海岸外的高分辨率MT观测中显而易见，这些观测显示了MT波高度复杂、多尺度的非线性瓦解。与文献中发现的其他空白一起，这些观察强烈建议对当前MT范式进行修订。野外实验：将进行为期3年的野外实验，以收集路易斯安那州海岸外前所未有的高分辨率(高达4赫兹)MT观测结果，以全面捕捉MT演化的细节。该遗址是一个独特的“天然实验室”：(I)每个冷季它经历20-30个锋面通道(MT的概率很高)；(Ii)可以对各种沉积类型(从粗砂到泥浆)进行海底诱导的耗散研究；(Iii)至关重要的是，它已经由http://www.wavcis.lsu.edu/，海岸研究所监测，该网络是由美国国家海洋和大气局和海洋观测中心赞助的一个海洋观测系统网络。WAVCIS将增强高分辨率能力，并在海岸和近海建立五个新的观测站。这些观测将被组织到一个公共数据库中。建模：拟议的工作是基于这样的假设：在一个普通的普罗德曼共振的MT事件中，俘获波也是被激发的。尽管它们通常不那么危险，但它们可能代表着这一过程的重要部分，并充当主浪的前兆。这项工作的重点是MT的传播阶段：将建立MT自由分量和受困分量的非线性演化的理论描述，包括孤立波，并将在实际地形中进行验证，并考虑到真实的底部摩擦。MT警告：数据分析和模式开发将整合到评估-学习-更正循环中，这将改善我们对过程的表示和我们预测MT事件的能力。将开发和测试有效的数值模型和预警策略。目前，MT预警系统主要依赖于大气数据的解译。新的高分辨率观测将用于将实时海洋反应的要素纳入本周期。

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.