They can thus cause extensive infrastructure damage, navigation and beach safety concerns, and human casualties ( Pattiaratchi and Wijeratne 2015 Rabinovich 2020). In terms of coastal risks, the meteotsunami surges (i.e., the maximum coastal sea levels) can be on the order of several meters as observed in the Adriatic Sea in 1978 ( Pattiaratchi and Wijeratne 2015 Rabinovich 2020). Under this condition, also referred as Proudman resonance ( Proudman 1929), the energy of the atmospheric disturbance is efficiently transferred to the background ocean waves which are amplified by an order of magnitude compared to the inverse barometer effect ( Vilibić 2008). Nowadays, meteotsunamis locally generated by weather systems are known to be fully amplified when an atmospheric disturbance travels at a speed U similar to the ocean waves ( c = g H, with g the gravity and H the ocean depth)-i.e., when the Froude number (Fr = U/ c) is close to 1.0 ( Vilibić 2008). The then sparse and low-quality tide gauge global network recorded (i) a mismatch between the analytically derived and observed arrival times of the tsunami waves resulting from the volcano collapse in the Pacific Ocean, and (ii) worldwide sea level oscillations as far away from the source as the English Channel. The existence of planetary-scale Lamb wave–driven meteotsunamis has been first hypothesized after the catastrophic eruption of the Krakatau volcano in 1883 ( Press and Harkrider 1966 Self and Rampino 1981). In the worldwide oceans, they excite atmospheric tsunamis or meteotsunamis-long waves in the tsunami frequency band generated by atmospheric disturbances ( Pattiaratchi and Wijeratne 2015 Rabinovich 2020)-which spread with much greater speeds than tsunami waves generated by volcanic eruptions or seismic activity ( Satake et al. They are associated with surface pressure oscillations of several hectopascals (hPa) per minute ( Press and Harkrider 1966 Harrison 2022) and their energy is dissipated toward the thermosphere ( Forbes et al. Lamb waves propagate horizontally in the atmosphere with a speed close to the mean sound speed ( Dragoni and Santoro 2020) and can circle the globe multiple times ( Press and Harkrider 1966 Amores et al. 2022) generated during these events, including acoustic-gravity waves ( Yeh and Liu 1974) and the most prominent Lamb waves ( Lamb 1911 Bretherton 1969), remains sporadically documented. However, the global impact of atmospheric waves ( Matoza et al. 1996), and many other planetary-scale processes. ![]() 2014), aerosol-driven reduction of solar radiation ( Kring et al. 2022) are known to cause extreme damage near their epicenters but also to affect the entire planet through megatsunamis ( Kharif and Pelinovsky 2005), acidification of the atmosphere and ocean ( Ohno et al. 2003) or asteroid impacts ( Chapman and Morrison 1994 Morgan et al. Keywords: Extreme events Sea level Surface layer Numerical analysis/modeling Ocean modelsĬatastrophic events such as volcano explosions ( Choi et al. Based on records of catastrophic events in Earth’s history, both scenarios are found to be realistic, and consequently, the global meteotsunami hazards should now be properly assessed to prepare for the next big volcanic eruption or asteroid impact even occurring inland. Planetary meteotsunami waves thus have the potential to cause serious coastal damages and even human casualties during volcanic explosions or asteroid impacts either releasing intense acoustic energy or producing internal atmospheric gravity waves triggering the deep-ocean Proudman resonance at a speed of ∼212 m s −1. These simulations demonstrate that the meteotsunami surges can be higher than 1 m (and up to 10 m) along more than 7% of the world coastlines. ![]() ![]() In practice, several process-oriented numerical experiments are designed to force a global ocean model with the realistic atmospheric response to the Hunga Tonga–Hunga Ha‘apai event rescaled in speed and amplitude. However, this study highlights that the mostly ignored destructive potential of planetary meteotsunami waves can be compared to the well-studied tsunami hazards. Recently, such ocean waves have been globally recorded after the Hunga Tonga–Hunga Ha‘apai volcano eruption on 15 January 2022, but did not pose any serious danger to the coastal communities. They mostly occur during supervolcano explosions or asteroid impacts capable to generate atmospheric acoustic-gravity waves including the Lamb waves that can circle the globe multiple times. Worldwide tsunamis driven by atmospheric waves-or planetary meteotsunami waves-are extremely rare events.
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