Análisis de la transferencia de oleaje producida en diferentestipologías de arrecife de coral en Recife (Brasil)
ABSTRACT: The coastal zone is one of the most dynamic, complex and productive systems that can be found in natural environments. These sectors favor the concentration of urban settlements, mainly due to industrial, fishing, tourism and transportation productivity. Specifically in Brazil, approximate...
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| Tipo de recurso: | tesis de maestría |
| Fecha de publicación: | 2020 |
| País: | España |
| Institución: | Universidad de Cantabria (UC) |
| Repositorio: | UCrea Repositorio Abierto de la Universidad de Cantabria |
| Idioma: | español |
| OAI Identifier: | oai:repositorio.unican.es:10902/19640 |
| Acceso en línea: | http://hdl.handle.net/10902/19640 |
| Access Level: | acceso abierto |
| Palabra clave: | Arrecifes de coral Coeficiente de transferencia de energía Protección costera Cambio climático Coral reefs Climate change Coastal protection Energy transfer coefficient |
| Sumario: | ABSTRACT: The coastal zone is one of the most dynamic, complex and productive systems that can be found in natural environments. These sectors favor the concentration of urban settlements, mainly due to industrial, fishing, tourism and transportation productivity. Specifically in Brazil, approximately 20% of the population is found in coastal municipalities and due to its location in the neotropical biogeographic region, its coastal zone is characterized by having varied ecosystems and natural environments, such as atolls, reefs, algae banks, estuaries, marshes, mangroves, among others. Ecosystems such as coral reefs have the ability to act as natural protection in the event of extreme waves, but strong urban pressure and climate change can degrade these environments, potentially causing a decrease in the protection service. Based on information from bathymetric profiles, hydrodynamic conditions measured in the field and maritime climate databases at depths waters, in this work an analysis of wave transfer has been carried out in fringing and platform coral reef profiles, using the IH2VOF model. In the first place, field measurements (from Costa et al. (2015)) have been used to validate the performance of the detail model, obtaining that it manages to represent the waves transferred along the profiles under study, both for mean and storm conditions. Additionally, within the validation process the influence of infragravitational wave has been analyzed through the generation of irregular waves with secondorder components, obtaining that this type of waves is of greater importance in the fringing reef, which is mainly due to breaking wave process on the crest of the reef, dissipating the energy of short waves (low periods). Subsequently, in order to characterize the energy transmission coefficient in the current maritime climate conditions, a description of mean and extreme conditions of the maritime climate in the area at depth water has been made. Thus, a set of sea states have been selected that have been propagated in front of the coral reef profiles. The results of this wave propagation process are used as initial conditions to carry out simulations with the IH2VOF, that allow obtaining the wave height transmitted in the fringing and platform reefs. In this way, the transmission coefficients for the current maritime climate conditions are determined. The analysis of the transmission coefficient under current conditions indicates that the two typologies considered have the capacity to attenuate the height of the incident wave. The fringing reef provides a greater protection service, being able to decrease the wave height by up to 94% at times of low tide, while the platform reef produces a maximum attenuation of 69% under the same conditions. The differences mentioned are mainly due to the fact that the fringing reef has a higher elevation at its crest, which causes the break of the waves at that point, while in the platform reef the dissipation of energy occurs as the waves propagates across the profile. Finally, with the aim of evaluating the effects of climate change on transmission coefficients in the future, effects of an increase in mean sea level and a decrease in the elevation of the crest of the reefs have been incorporated, making new propagations for a storm condition and obtaining the variations of the transmission coefficient through simulations carried out with the IH2VOF. The results indicate that, when considering these two scenarios together, the wave height transmission coefficient increases by 40% in the fringing reef and by 69% in the platform reef. Furthermore, the values of the transmission coefficient under these scenarios cannot be described by the linear regression adjustment carried out for the current conditions, so it is considered that they must be analyzed independently to obtain adjustments that allow predicting future variations with a greater precision. |
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