Meteotsunamis in Brazil: an overview of known occurrences from 1977 to 2020
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Meteotsunamis in Brazil: an overview of known occurrences from 1977 to 2020 Rogério Neder Candella1 · Carlos Eduardo Salles de Araujo2 Received: 16 May 2020 / Accepted: 17 September 2020 © Springer Nature B.V. 2020
Abstract From 1977 to March 2020, eight atmospherically induced tsunami-like events have been observed in Brazil. Six of them occurred in the southern region of the country, where the atmosphere tends to be more unstable due to the passage of low-pressure systems, which often move from the south to the north along the coast. This trajectory combined with the shallow continental shelf in the region can favor the occurrence of resonance and, consequently, the amplification of the waves. Most events resulted only in material losses, sometimes severe, but at least one fatal victim was registered. On the vast majority of the occasions, seven in eight, the tsunami-like waves happened on the open coast, and half of them under bad-weather situations. The sparse tide gauge network and its low sampling frequency surely prevented them from being recorded, and mostly the only references about these events came only from the media. Keywords Meteotsunamis · Brazil · Known occurrences · Geographical distribution
1 Introduction Meteorological tsunamis or meteotsunamis are sea-level oscillations with periods from a few minutes to about three hours and typical spatial scales from a few hundred meters to approximately 100–150 km (Rabinovich 2020). These oscillations have the same temporal and spatial scales as ordinary tsunami waves and can affect coastal areas in a similar destructive way (Monserrat et al. 2006). They are generated by traveling atmospheric disturbances such as frontal passages, gravity waves, squall lines, and significant pressure jumps (Bailey et al. 2014), rather than by underwater earthquakes, landslides or volcanic eruptions (Monserrat et al. 2006). The generation and evolution of meteotsunamis typically begins with atmospheric sudden pressure jumps that cause minor changes in sea level according to the inverted * Rogério Neder Candella [email protected]; [email protected] 1
Department of Oceanography, Instituto de Estudos do Mar Almirante Paulo Moreira, Arraial do Cabo, RJ, Brazil
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Centro de Informações de Recursos Ambientais e de Hidrometeorologia de Santa Catarina, Empresa de Pesquisa Agropecuária e Extensão Rural de Santa Catarina, Florianópolis, SC, Brazil
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barometer effect, creating propagating ocean waves. When propagation speed of the pressure perturbation matches the speed of the ocean waves, the resonant energy transfer mechanisms produce significantly increased sea-level response (Vilibić et al. 2016; Bailey et al. 2014; Renault et al. 2011). Bailey et al. (2014) reported that the Proudman resonance (Proudman 1929) and, in some cases, the Greenspan resonance (Greenspan 1956) are the main mechanisms that generate this phenomenon along the East Coast of the United States. As the ocean wave travels toward the coast, local shoali
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