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

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This is a comprehensive investigation of the meteotsunami (MT) evolution and its interaction with the ocean environment. MT is sea-level oscillations in the tsunami time scale (minutes to hours) generated by atmosphere perturbations, such as squall lines and frontal passages. MT events are common and documented all over the world. Like tsunami, strong MTs pose a serious threat to human life and coastal infrastructure. The team proposes to conduct a 3-year field experiment to collect unprecedented high-resolution observations off Louisiana (chosen for high MT probability, various bottom friction and existing NOAA and BOEM observations) to fully capture the nonlinear transformation of a MT from generation to its shoreline manifestation. Theoretical analyses and numerical simulations will be combined with the observational data to predict how the MTs transform as they approach shore. The project leverages UK researchers who will collaborate with the team at no cost (being funded by UK Natural Environment Research Council (NERC) under the bilateral agreement). The proposed data collection and the resulting public database will provide a unique source of high-resolution information, leading to an essentially new picture of MT. The new data will produce robust statistics and allow for testing of all future theoretical and numerical developments. Thus, representation of the MT process in numerical models and their ability to predict MT events will be improved. Understanding the MT evolution and improving MT early-warning strategies will protect small fishing vessels and coastal communities. The project will also upgrade the Wave-Current-Surge Information System in the Gulf of Mexico with new high-resolution observation capabilities. Two Ph.D. students will be trained and outreach activities through local K-12 education are planned over the course of the project.Compared to tsunami, MT evolution is much more nonlinear and more strongly affected by bottom friction. Thus, knowledge acquired in the study of seismic tsunami is not readily transferable to MT research. The events are generated by an atmospheric disturbance that moves at the speed of the oceanic response, which is assumed to propagate as a linear long wave. However, this assumption has not yet been critically tested because of the poor spatial and temporal resolution of available observations. 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. Data analysis and model development will be integrated into an evaluate-learn-correct cycle that will improve representation of the process and ability to anticipate MT events. Effective numerical models and early-warning strategies could be developed and tested following the findings of this project. Presently, MT early-warning systems mostly rely on interpreting atmospheric data. The new high-resolution observations from this project will be used to incorporate in this cycle elements of real-time ocean response.