Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Nat. Hazards Earth Syst. Sci., 14, 3195-3205, 2014
https://doi.org/10.5194/nhess-14-3195-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
03 Dec 2014
Analysis of extreme wave events on the southern coast of Brazil
P. V. Guimarães3,1, L. Farina3,2, and E. E. Toldo Jr.1 1Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Campus do Vale Av. Bento Gonçalves 9500, Porto Alegre, RS, Brasil
2Instituto de Matemática, Universidade Federal do Rio Grande do Sul, Campus do Vale Av. Bento Gonçalves 9500, Porto Alegre, RS, Brasil
3BCAM, Basque Center for Applied Mathematics, Alameda de Mazarredo, 14, 48009, Bilbao, Basque Country, Spain
Abstract. Using the wave model SWAN (simulating waves nearshore), high waves on the southwestern Atlantic generated by extra-tropical cyclones are simulated from 2000 to 2010, and their impact on the Rio Grande do Sul (RS) coast is studied. The modeled waves are compared with buoy data and good agreement is found. The six extreme events in the period that presented significant wave heights above 5 m, on a particular point of interest, are investigated in detail. It is found that the cyclogenetic pattern between the latitudes 31.5 and 34° S is the most favorable for developing high waves. Hovmöller diagrams for deep water show that the region between the south of Rio Grande do Sul up to a latitude of 31.5° S is the most energetic during a cyclone's passage, although the event of May 2008 indicates that the location of this region can vary, depending on the cyclone's displacement. On the other hand, the Hovmöller diagrams for shallow water show that the different shoreface morphologies were responsible for focusing or dissipating the waves' energy; the regions found are in agreement with the observations of erosion and progradation regions. It can be concluded that some of the urban areas of the beaches of Hermenegildo, Cidreira, Pinhal, Tramandaí, Imbé and Torres have been more exposed during the extreme wave events on the Rio Grande do Sul coast, and are more vulnerable to this natural hazard.

Citation: Guimarães, P. V., Farina, L., and Toldo Jr., E. E.: Analysis of extreme wave events on the southern coast of Brazil, Nat. Hazards Earth Syst. Sci., 14, 3195-3205, https://doi.org/10.5194/nhess-14-3195-2014, 2014.
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Short summary
This manuscript presents an investigation of extreme waves events in the southwestern Atlantic Ocean and the impacts on the coast of Rio Grande do Sul in Brazil. Six extreme waves events generated by extra-tropical cyclones are selected from 2000 to 2010, and their impact on the Rio Grande do Sul coast is studied.
This manuscript presents an investigation of extreme waves events in the southwestern Atlantic...
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