http://hdl.handle.net/2117/3507 Wed, 22 May 2013 01:59:19 GMT 2013-05-22T01:59:19Z webmaster.bupc@upc.edu Universitat Politècnica de Catalunya. Servei de Biblioteques i Documentació no http://hdl.handle.net/2117/18875 Title: Overtopping formula for vertical tiers-headed breakwaters Authors: Altomare, Corrado; Damiani, Leonardo; Gironella Cobos, Xavier Abstract: The semi-empirical methods are useful tools to understand the wave overtopping phenomena, but uncertainty remains on their applicability. It’s necessary to carry out campaign surveys or laboratory tests to support them. In this paper we apply the methods proposed in the European Overtopping Manual (2007) in order to assess the flows over a vertical breakwater, marking the need to calibrate those methodologies to take into account the peculiar geometry of the structural system. This was done by introducing appropriate correction factors. The results show an improved accuracy, among numerical results and physical ones. Thu, 18 Apr 2013 15:12:49 GMT http://hdl.handle.net/2117/18875 2013-04-18T15:12:49Z Altomare, Corrado; Damiani, Leonardo; Gironella Cobos, Xavier no The semi-empirical methods are useful tools to understand the wave overtopping phenomena, but uncertainty remains on their applicability. It’s necessary to carry out campaign surveys or laboratory tests to support them. In this paper we apply the methods proposed in the European Overtopping Manual (2007) in order to assess the flows over a vertical breakwater, marking the need to calibrate those methodologies to take into account the peculiar geometry of the structural system. This was done by introducing appropriate correction factors. The results show an improved accuracy, among numerical results and physical ones. http://hdl.handle.net/2117/18748 Title: Incorporation of continental and urban run-off into a coastal circulation model: application to the Catalan coast Authors: Liste, Maria; Grifoll Colls, Manel; Keupers, Ingrid; Monbaliu, Jaak; Espino Infantes, Manuel Abstract: A 3D hydrodynamical model has been set up to incorporate the continental and urban run-off into the Catalan Coastal waters. Particular attention was paid to introducing correctly the freshwater plumes and attention was also paid to determinate the influence of the land discharge profile with regard to the distributed continental run-off. The model domain includes a small part of the Catalan Coast where the combination of local land topography with torrential rainfall caused considerable local runoff on a short period of time with a large impact on the receiving coastal waters. The Regional Ocean Modeling System (ROMS) simulations were used to examine the dispersal to a freshwater delivery from two relevant event; a low river discharge typical of mean conditions during April 2011 and a high discharge representative of the storm event during March 2011 are considered. We have observed the plume responses to an abrupt change in river discharge. During the mean conditions, low salinity water is concentrated around the rivers mouth while during the flood event, the plume spread offshore in the direction of river water outflow and turned downstream close to the coast. The differences between a simulation including the river outflow as a land forcing and a simulation including river and urban runoff as a land forcing suggested that the urban runoff plays an important role in the spreading and shape of the river plume. Tue, 09 Apr 2013 18:04:52 GMT http://hdl.handle.net/2117/18748 2013-04-09T18:04:52Z Liste, Maria; Grifoll Colls, Manel; Keupers, Ingrid; Monbaliu, Jaak; Espino Infantes, Manuel no land boundary fluxes, urban runoff, river discharge, freshwater plume A 3D hydrodynamical model has been set up to incorporate the continental and urban run-off into the Catalan Coastal waters. Particular attention was paid to introducing correctly the freshwater plumes and attention was also paid to determinate the influence of the land discharge profile with regard to the distributed continental run-off. The model domain includes a small part of the Catalan Coast where the combination of local land topography with torrential rainfall caused considerable local runoff on a short period of time with a large impact on the receiving coastal waters. The Regional Ocean Modeling System (ROMS) simulations were used to examine the dispersal to a freshwater delivery from two relevant event; a low river discharge typical of mean conditions during April 2011 and a high discharge representative of the storm event during March 2011 are considered. We have observed the plume responses to an abrupt change in river discharge. During the mean conditions, low salinity water is concentrated around the rivers mouth while during the flood event, the plume spread offshore in the direction of river water outflow and turned downstream close to the coast. The differences between a simulation including the river outflow as a land forcing and a simulation including river and urban runoff as a land forcing suggested that the urban runoff plays an important role in the spreading and shape of the river plume. http://hdl.handle.net/2117/18379 Title: Indagine sperimentale sui processi di trasmissione di energia e massa a tergo di barriere frangiflutti a porosità controllata Authors: Marzeddu, Andrea Mon, 18 Mar 2013 19:39:18 GMT http://hdl.handle.net/2117/18379 2013-03-18T19:39:18Z Marzeddu, Andrea no http://hdl.handle.net/2117/17525 Title: Los desafíos de las zonas costeras en el siglo XXI: proposiciones para la cumbre de la tierra Río+20 Authors: Baztan, Juan; Vanderlinden, J.P.; Chouinard, O.; Sánchez-Arcilla Conejo, Agustín Abstract: 20 años han pasado desde la cumbre de la Tierra en 1992: 20 años de esfuerzos para entender, informar y mejorar las relaciones entre nuestras sociedades y las zonas costeras. Estos esfuerzos han cristalizado en un aumento de la concienciación medioambiental y en una serie de acuerdos como, por ejemplo, los capítulos 17 y 31 de la Agenda 21, “Jakarta Mandate on the Conservation and Sustainable Use of Marine and Coast Biological Diversity” o “UN Regional Seas and Action Plans”. Acuerdos internacionales que son implementados mediante cientos de leyes, planes, protocolos y convenciones nacionales y transnacionales. Por ejemplo, en el último Dictamen del Comité Económico y Social Europeo sobre GIZC (14/12/2010) leemos: “La presión demográfica, inmobiliaria, agrícola, económica y turística en estas zonas puede constituir un peligro para su propio poder de atracción y su futuro. Únicamente la adopción de políticas basadas en la noción de desarrollo sostenible, tanto desde el punto de vista económico como social y medioambiental, puede garantizar un futuro apacible a las regiones costeras”, texto que ilustra los esfuerzos nacionales e internacionales para regular y mejorar la GIZC. A pesar del esfuerzo, la mayoría de indicadores nos muestran que la balanza democrática del desarrollo sigue degradándose y que el equilibrio de las comunidades se supedita, con demasiada frecuencia, a una rentabilidad a corto plazo independientemente de las consecuencias sociales, ecológicas y económicas a medio y largo plazo. Fri, 25 Jan 2013 17:10:42 GMT http://hdl.handle.net/2117/17525 2013-01-25T17:10:42Z Baztan, Juan; Vanderlinden, J.P.; Chouinard, O.; Sánchez-Arcilla Conejo, Agustín no 20 años han pasado desde la cumbre de la Tierra en 1992: 20 años de esfuerzos para entender, informar y mejorar las relaciones entre nuestras sociedades y las zonas costeras. Estos esfuerzos han cristalizado en un aumento de la concienciación medioambiental y en una serie de acuerdos como, por ejemplo, los capítulos 17 y 31 de la Agenda 21, “Jakarta Mandate on the Conservation and Sustainable Use of Marine and Coast Biological Diversity” o “UN Regional Seas and Action Plans”. Acuerdos internacionales que son implementados mediante cientos de leyes, planes, protocolos y convenciones nacionales y transnacionales. Por ejemplo, en el último Dictamen del Comité Económico y Social Europeo sobre GIZC (14/12/2010) leemos: “La presión demográfica, inmobiliaria, agrícola, económica y turística en estas zonas puede constituir un peligro para su propio poder de atracción y su futuro. Únicamente la adopción de políticas basadas en la noción de desarrollo sostenible, tanto desde el punto de vista económico como social y medioambiental, puede garantizar un futuro apacible a las regiones costeras”, texto que ilustra los esfuerzos nacionales e internacionales para regular y mejorar la GIZC. A pesar del esfuerzo, la mayoría de indicadores nos muestran que la balanza democrática del desarrollo sigue degradándose y que el equilibrio de las comunidades se supedita, con demasiada frecuencia, a una rentabilidad a corto plazo independientemente de las consecuencias sociales, ecológicas y económicas a medio y largo plazo. http://hdl.handle.net/2117/16293 Title: The compositional meaning of a detection limit Authors: van den Boogaart, Karl Gerard; Tolosana Delgado, Raimon; Bren, Matevz Abstract: Conclusions The chemical interpretation of the detection limit and its stochastic model counterpart has thus different consequences for the statistical analysis than we would expect from the word by word interpretation of “below detection limit” as a concentration below some limit. The state of the art model on BDL compositional analysis is biased. Some ideas are not directly applicable to the true effects of measurement errors near the detection limit. Even the basic principles like subcompositional coherence and the requirement of the independence of the analysis from the total are not fully valid near the detection limit. Wed, 18 Jul 2012 11:55:26 GMT http://hdl.handle.net/2117/16293 2012-07-18T11:55:26Z van den Boogaart, Karl Gerard; Tolosana Delgado, Raimon; Bren, Matevz no Conclusions The chemical interpretation of the detection limit and its stochastic model counterpart has thus different consequences for the statistical analysis than we would expect from the word by word interpretation of “below detection limit” as a concentration below some limit. The state of the art model on BDL compositional analysis is biased. Some ideas are not directly applicable to the true effects of measurement errors near the detection limit. Even the basic principles like subcompositional coherence and the requirement of the independence of the analysis from the total are not fully valid near the detection limit. http://hdl.handle.net/2117/16292 Title: Unmixing compositional data with Bayesian techniques Authors: Tolosana Delgado, Raimon Abstract: A general problem in compositional data analysis is the unmixing of a composition into a series of pure endmembers. In its most complex version, one does neither know the composition of these endmembers, nor their relative contribution to each observed composition. The problem is particularly cumbersome if the number of endmembers is larger than the number of observed components. This contribution proposes a possible solution of this under-determined problem. The proposed method starts assuming that the endmember composition is known. Then, a geometric characterization of the problem allows to nd the set of possible endmember proportions compatible with the observed composition. Within this set any solution may be valid, but some are more likely than other. To use this idea and choose the "most likely" solution in each case, the problem can be tackled with Bayesian Markov-Chain Monte-Carlo techniques. Finally, once we are familiar with MCMC, it is quite traightforward to allow the endmember compositions to randomly vary, and use the same MCMC to estimate the endmember composition most compatible with the studied data. Wed, 18 Jul 2012 11:42:33 GMT http://hdl.handle.net/2117/16292 2012-07-18T11:42:33Z Tolosana Delgado, Raimon no A general problem in compositional data analysis is the unmixing of a composition into a series of pure endmembers. In its most complex version, one does neither know the composition of these endmembers, nor their relative contribution to each observed composition. The problem is particularly cumbersome if the number of endmembers is larger than the number of observed components. This contribution proposes a possible solution of this under-determined problem. The proposed method starts assuming that the endmember composition is known. Then, a geometric characterization of the problem allows to nd the set of possible endmember proportions compatible with the observed composition. Within this set any solution may be valid, but some are more likely than other. To use this idea and choose the "most likely" solution in each case, the problem can be tackled with Bayesian Markov-Chain Monte-Carlo techniques. Finally, once we are familiar with MCMC, it is quite traightforward to allow the endmember compositions to randomly vary, and use the same MCMC to estimate the endmember composition most compatible with the studied data. http://hdl.handle.net/2117/16254 Title: Geochemistry versus grain-size relations of sediments in the light of comminution, chemical alteration, and contrasting source rocks Authors: von Eynatten, Hilmar; Tolosana Delgado, Raimon Abstract: Around 170 sediment samples from glacial and proximal glacio-fluvial deposits have been analysed for their geochemical composition. Samples derive from two strongly contrasting source areas (granitoids vs. amphibolite) and cover a broad grain-size range from coarse sand to clay. Following descriptive data evaluation, the relation of sediment geochemical composition versus grain size is modelled using linear regression techniques in the Aitchison geometry of the simplex in order to (i) describe the effects of comminution on the composition of individual grain size fractions, (ii) describe the influence of inherited mineral-specific grain-size distributions for contrasting source rocks, and (iii) to test for any potential influence of chemical weathering. Results indicate strong overall grain-size control on sediment composition that is largely reflecting the greater grain-size control on mineralogy. Comminution leads to overall strong enrichment of sheet silicates in the fine-grained fraction at the expense of quartz and, less pronounced, feldspars. Specific elements such as Ca, P, and Ti related to certain minerals do not follow this general trend and clearly indicate source-rock dependent enrichment of certain minerals (e.g. apatite, Ti-minerals) in medium grain-size fractions. Estimates of mineral compositions obtained from a geometric endmember approach support these conclusions. Chemical weathering is shown to be negligible. Mon, 16 Jul 2012 08:34:58 GMT http://hdl.handle.net/2117/16254 2012-07-16T08:34:58Z von Eynatten, Hilmar; Tolosana Delgado, Raimon no Around 170 sediment samples from glacial and proximal glacio-fluvial deposits have been analysed for their geochemical composition. Samples derive from two strongly contrasting source areas (granitoids vs. amphibolite) and cover a broad grain-size range from coarse sand to clay. Following descriptive data evaluation, the relation of sediment geochemical composition versus grain size is modelled using linear regression techniques in the Aitchison geometry of the simplex in order to (i) describe the effects of comminution on the composition of individual grain size fractions, (ii) describe the influence of inherited mineral-specific grain-size distributions for contrasting source rocks, and (iii) to test for any potential influence of chemical weathering. Results indicate strong overall grain-size control on sediment composition that is largely reflecting the greater grain-size control on mineralogy. Comminution leads to overall strong enrichment of sheet silicates in the fine-grained fraction at the expense of quartz and, less pronounced, feldspars. Specific elements such as Ca, P, and Ti related to certain minerals do not follow this general trend and clearly indicate source-rock dependent enrichment of certain minerals (e.g. apatite, Ti-minerals) in medium grain-size fractions. Estimates of mineral compositions obtained from a geometric endmember approach support these conclusions. Chemical weathering is shown to be negligible. http://hdl.handle.net/2117/15769 Title: Predicción morfodinámica operacional: una nueva estrategia de gestión del litoral Authors: Sánchez-Arcilla Conejo, Agustín; Gracia Garcia, Vicente; García León, Manel; Solé Tasias, Josep Maria Abstract: Una parte muy importante de las playas de arena de España pueden ser consideradas como playas urbanas y por tanto se encuentran limitadas en su parte continental por todo tipo de infraestructuras (paseos marítimos, calles, comercios, carreteras, vías de tren, etc.). En la mayoría de ocasiones esta ocupación del dominio natural no ha tenido en cuenta su alta variabilidad y dinamismo por lo que resultan especialmente vulnerables al impacto de temporales. Conocer con antelación cual será la respuesta de un tramo de costa frente a unas determinadas condiciones hidrodinámicas es altamente interesante puesto que permitiría escoger de antemano la mejor estrategia de defensa minimizando en lo posible los impactos. El principal objetivo de este trabajo es evaluar la viabilidad de un sistema de predicción morfodinámico, PRE‐MOS (Pre ‐ Morphodynamic Operational System), como herramienta de alarma temprana y gestión de la costa. Para ello se pretende reproducir la respuesta morfodinámica de dos playas de la litoral noroccidental mediterráneo español frente al impacto del temporal de Diciembre de 2008, que arrasó esta parte de la costa causando graves daños en paseos marítimos y otras infraestructuras. PREMOS se estructura en tres grandes módulos: (1) una unidad meteorológica representada por las predicciones de viento realizadas de forma rutinaria por el Servei Meteorològic de Catalunya mediante los modelos MM5 y WRF (Dudhia, 1993) para el mediterráneo noroccidental y que sirven como condición de partida a (2) la unidad de generación y propagación del oleaje, (SWAN, Booj et al. 1996) en donde se reproducen los procesos del oleaje que finalmente son utilizados en (3) un modelo de evolución morfodinámico (XBEACH, Roelvink et al. 2009) en donde se analiza la respuesta de la costa frente a estas acciones de oleaje. SWAN es un modelo de tercera generación de oleaje que ha sido previamente validado para distintos temporales para la costa mediterránea española (Alomar et al., 2009) mientras que el modelo XBEACH ha sido utilizado para evaluar los procesos de rebase y rotura en un tramo de costa del delta del Ebro (mediterráneo noroccidental) por García et al. (2011). El artículo describirá en detalle los resultados obtenidos en dos playas de la costa Catalana, realizando un análisis crítico sobre las sensibilidad del sistema frente a condiciones de partida (batimetría y condiciones de oleaje) distintas con el fin de determinar la utilidad de este tipo de aproximaciones para la gestión de costas. Wed, 02 May 2012 14:19:34 GMT http://hdl.handle.net/2117/15769 2012-05-02T14:19:34Z Sánchez-Arcilla Conejo, Agustín; Gracia Garcia, Vicente; García León, Manel; Solé Tasias, Josep Maria no Impacto de temporales, gestión, sistema operacionales, SWAN, XBEACH Una parte muy importante de las playas de arena de España pueden ser consideradas como playas urbanas y por tanto se encuentran limitadas en su parte continental por todo tipo de infraestructuras (paseos marítimos, calles, comercios, carreteras, vías de tren, etc.). En la mayoría de ocasiones esta ocupación del dominio natural no ha tenido en cuenta su alta variabilidad y dinamismo por lo que resultan especialmente vulnerables al impacto de temporales. Conocer con antelación cual será la respuesta de un tramo de costa frente a unas determinadas condiciones hidrodinámicas es altamente interesante puesto que permitiría escoger de antemano la mejor estrategia de defensa minimizando en lo posible los impactos. El principal objetivo de este trabajo es evaluar la viabilidad de un sistema de predicción morfodinámico, PRE‐MOS (Pre ‐ Morphodynamic Operational System), como herramienta de alarma temprana y gestión de la costa. Para ello se pretende reproducir la respuesta morfodinámica de dos playas de la litoral noroccidental mediterráneo español frente al impacto del temporal de Diciembre de 2008, que arrasó esta parte de la costa causando graves daños en paseos marítimos y otras infraestructuras. PREMOS se estructura en tres grandes módulos: (1) una unidad meteorológica representada por las predicciones de viento realizadas de forma rutinaria por el Servei Meteorològic de Catalunya mediante los modelos MM5 y WRF (Dudhia, 1993) para el mediterráneo noroccidental y que sirven como condición de partida a (2) la unidad de generación y propagación del oleaje, (SWAN, Booj et al. 1996) en donde se reproducen los procesos del oleaje que finalmente son utilizados en (3) un modelo de evolución morfodinámico (XBEACH, Roelvink et al. 2009) en donde se analiza la respuesta de la costa frente a estas acciones de oleaje. SWAN es un modelo de tercera generación de oleaje que ha sido previamente validado para distintos temporales para la costa mediterránea española (Alomar et al., 2009) mientras que el modelo XBEACH ha sido utilizado para evaluar los procesos de rebase y rotura en un tramo de costa del delta del Ebro (mediterráneo noroccidental) por García et al. (2011). El artículo describirá en detalle los resultados obtenidos en dos playas de la costa Catalana, realizando un análisis crítico sobre las sensibilidad del sistema frente a condiciones de partida (batimetría y condiciones de oleaje) distintas con el fin de determinar la utilidad de este tipo de aproximaciones para la gestión de costas. http://hdl.handle.net/2117/15527 Title: Checking model-data weather hazard occurrence fit in the context of climate change Authors: Tolosana Delgado, Raimon; Ortego Martínez, María Isabel; Egozcue Rubí, Juan José; Sánchez-Arcilla Conejo, Agustín Abstract: In climate change impact studies it is common to run a given response model (from ecosystem changes to wavestorm or landslide occurrence) nested into one of the available long-term Global or Regional Circulation Models (GCM, RCM) reproducing the climate for the XX century or predicting it for the XXI. In this way, it is expected to capture the average behaviour of the studied system to a changing climate forcing: in other words, with such response forecasts, one does not actually expect to be able to reproduce each and every single event, but rather its statistical behaviour. Regarding weather-related hazard, the relevant statistical properties are the occurrence return period of events, and their expected magnitude. The present study focuses on wave storm occurrence, and aims at presenting a general methodology to check the adequate reproduction of the return period of hazardous weather-related events by such response forecast models. This is attained by analysing a compound data set formed by series of real data (typically of around 20-30 years in the last decades of the XX century or the beginning of the XXI one) and longer hind- or forecast series. Occurrence of a stormy event is considered to follow an inhomogeneous Poisson process, with: a linear trend to capture climate change, and a step in the junction real data-forecast data to capture systematic model biases. A Bayesian method is proposed to assess the influence of these two elements, i.e the presence/absence of a climate trend and the adequate reproduction of the statistical properties of wavestorm occurrence by forecasting models. Results suggest a non-significant trend albeit negative trend in the storm occurrence, and an inability of the used forecast model to reproduce wavestorm occurrence. Thu, 08 Mar 2012 12:06:21 GMT http://hdl.handle.net/2117/15527 2012-03-08T12:06:21Z Tolosana Delgado, Raimon; Ortego Martínez, María Isabel; Egozcue Rubí, Juan José; Sánchez-Arcilla Conejo, Agustín no In climate change impact studies it is common to run a given response model (from ecosystem changes to wavestorm or landslide occurrence) nested into one of the available long-term Global or Regional Circulation Models (GCM, RCM) reproducing the climate for the XX century or predicting it for the XXI. In this way, it is expected to capture the average behaviour of the studied system to a changing climate forcing: in other words, with such response forecasts, one does not actually expect to be able to reproduce each and every single event, but rather its statistical behaviour. Regarding weather-related hazard, the relevant statistical properties are the occurrence return period of events, and their expected magnitude. The present study focuses on wave storm occurrence, and aims at presenting a general methodology to check the adequate reproduction of the return period of hazardous weather-related events by such response forecast models. This is attained by analysing a compound data set formed by series of real data (typically of around 20-30 years in the last decades of the XX century or the beginning of the XXI one) and longer hind- or forecast series. Occurrence of a stormy event is considered to follow an inhomogeneous Poisson process, with: a linear trend to capture climate change, and a step in the junction real data-forecast data to capture systematic model biases. A Bayesian method is proposed to assess the influence of these two elements, i.e the presence/absence of a climate trend and the adequate reproduction of the statistical properties of wavestorm occurrence by forecasting models. Results suggest a non-significant trend albeit negative trend in the storm occurrence, and an inability of the used forecast model to reproduce wavestorm occurrence. http://hdl.handle.net/2117/14666 Title: Wave reflection, transmission and spectral changes at permeable low-crested structures Authors: Sierra Pedrico, Juan Pablo; Dowding, D.D.; Persetto, Vito; Oliveira, Tiago Castro Alves; Gironella Cobos, Xavier; Mösso Aranda, César; Mestres Ridge, Marc Abstract: Physical model tests were carried out in order to improve the understanding about the hydrodynamic processes that take place around a LCS when it is under wave attack. In particular, the wave transmission and reflection coefficients as well as the spectrum transformation were analysed for both emerged and submerged structures. The results of the experiments indicated that there is a clear inverse proportionality between the transmission (Kt) and reflection (Kr) coefficients and the wave steepness sop. This trend is much more noticeable for emerged than for submerged structures. A comparison with some widely employed formulae was also made; in most of the cases these expressions underpredicted Kt and overpredicted Kr. Moreover, the spectral changes in the waves transmitted through the structure were analyzed, showing a shift of energy to higher frequency bands greater than that observed in previous works. It was also noted that the higher the sop, the more likely it is for the transmitted energy to be retained in the lower frequency bands. Wed, 18 Jan 2012 19:36:35 GMT http://hdl.handle.net/2117/14666 2012-01-18T19:36:35Z Sierra Pedrico, Juan Pablo; Dowding, D.D.; Persetto, Vito; Oliveira, Tiago Castro Alves; Gironella Cobos, Xavier; Mösso Aranda, César; Mestres Ridge, Marc no Low-crested structures, Wave transmission, Wave reflection Physical model tests were carried out in order to improve the understanding about the hydrodynamic processes that take place around a LCS when it is under wave attack. In particular, the wave transmission and reflection coefficients as well as the spectrum transformation were analysed for both emerged and submerged structures. The results of the experiments indicated that there is a clear inverse proportionality between the transmission (Kt) and reflection (Kr) coefficients and the wave steepness sop. This trend is much more noticeable for emerged than for submerged structures. A comparison with some widely employed formulae was also made; in most of the cases these expressions underpredicted Kt and overpredicted Kr. Moreover, the spectral changes in the waves transmitted through the structure were analyzed, showing a shift of energy to higher frequency bands greater than that observed in previous works. It was also noted that the higher the sop, the more likely it is for the transmitted energy to be retained in the lower frequency bands. http://hdl.handle.net/2117/14664 Title: Short-term morphodynamic changes in a fetch limited beach at the Ebro delta (Spain), under low wave-energy conditions Authors: Mösso Aranda, César; Sierra Pedrico, Juan Pablo; Gracia Garcia, Vicente; Mestres Ridge, Marc; Rodríguez Allende, Andrés Abstract: Sandy beaches in fetch-limited environments are protected from large ocean-generated swell waves, and fetch characteristics allow local wind-generated waves and currents to develop and drive the main morphodynamic processes. The morphodynamics of these low-energy beaches present a peculiar behaviour since there is not a dominant forcing mechanism inducing the beach changes. The main objective of this work is to describe and quantify the observed morphodynamic changes at the barred, quasi longshore-uniform beach of the Trabucador Bar at the Ebro Delta (Spain) under low-energy conditions. A nine-day field campaign was carried out within the framework of the European project FANS (Fluxes Across Narrow Shelves. The Ebro Delta Case) supported by the EC MAST-III Research Programme, (Contract No. MAS3-CT95-0037, DG12 – ESCY) and the measurements included a detailed topo-bathymetric surveying at the beginning and at the end of the campaign, video recordings covering the whole domain of the study area, surf zone waves and currents time series obtained at different positions and depths, nearshore pressure and horizontal velocities time series outside the surf zone. The results show that the beach underwent important longshore and cross-shore (the breaching of the submerged bar) morphodynamic changes under low-energy conditions. The observations suggest that the low-energy wave field and the beach profile played a key role in the generation of low frequency oscillations and rip currents that reshaped the whole study zone. Wed, 18 Jan 2012 19:28:00 GMT http://hdl.handle.net/2117/14664 2012-01-18T19:28:00Z Mösso Aranda, César; Sierra Pedrico, Juan Pablo; Gracia Garcia, Vicente; Mestres Ridge, Marc; Rodríguez Allende, Andrés no Fetch limited beaches, coastal morphodynamics, field measurements, Ebro Delta Sandy beaches in fetch-limited environments are protected from large ocean-generated swell waves, and fetch characteristics allow local wind-generated waves and currents to develop and drive the main morphodynamic processes. The morphodynamics of these low-energy beaches present a peculiar behaviour since there is not a dominant forcing mechanism inducing the beach changes. The main objective of this work is to describe and quantify the observed morphodynamic changes at the barred, quasi longshore-uniform beach of the Trabucador Bar at the Ebro Delta (Spain) under low-energy conditions. A nine-day field campaign was carried out within the framework of the European project FANS (Fluxes Across Narrow Shelves. The Ebro Delta Case) supported by the EC MAST-III Research Programme, (Contract No. MAS3-CT95-0037, DG12 – ESCY) and the measurements included a detailed topo-bathymetric surveying at the beginning and at the end of the campaign, video recordings covering the whole domain of the study area, surf zone waves and currents time series obtained at different positions and depths, nearshore pressure and horizontal velocities time series outside the surf zone. The results show that the beach underwent important longshore and cross-shore (the breaching of the submerged bar) morphodynamic changes under low-energy conditions. The observations suggest that the low-energy wave field and the beach profile played a key role in the generation of low frequency oscillations and rip currents that reshaped the whole study zone. http://hdl.handle.net/2117/14344 Title: Caracterização da agitação marítima ao largo de Maputo Authors: Guiloviça, C.B.; Oliveira, Tiago Castro Alves; Palalane, J.; Grifoll Colls, Manel; Gómez Aguar, Jesús Javier; Espino Infantes, Manuel Abstract: O objectivo deste trabalho é fazer a caracterização da agitação marítima ao largo de Maputo. Na ausência de dados de bóias e dados visuais que permitissem executar uma caracterização da agitação a longo prazo optou-se pela utilização de dados numéricos de retro-analise. Utilizaram-se resultados das predições oceânicas de escala global da NOAA/NWS/NCEP (National Oceanic and Atmospheric Admistration, National Wether Service, National Center for Environmental Prediction, as três dos Estados Unidos da America) que tem como base o modelo numérico WAVEWATCH III (Tolman, 2002) que utiliza dados do NCEP para definir as condições fronteira para o modelo. Efectuou-se uma analise a longo prazo tanto do clima médio como extremo e estudaram-se quais as funções de distribuição de probabilidade para análise extrema (Lognormal, Exponencial, Weibull, Gumbel e Frechet) melhor se adaptam ao clima marítimo da região. Os resultados serão apresentados com o objectivo de compreender que condições de agitação marítimas devem ser utilizadas no dimensionamento de estruturas (para diferentes períodos de retorno) bem como para estudos relacionados com transporte de sedimentos. Wed, 28 Dec 2011 19:00:20 GMT http://hdl.handle.net/2117/14344 2011-12-28T19:00:20Z Guiloviça, C.B.; Oliveira, Tiago Castro Alves; Palalane, J.; Grifoll Colls, Manel; Gómez Aguar, Jesús Javier; Espino Infantes, Manuel no O objectivo deste trabalho é fazer a caracterização da agitação marítima ao largo de Maputo. Na ausência de dados de bóias e dados visuais que permitissem executar uma caracterização da agitação a longo prazo optou-se pela utilização de dados numéricos de retro-analise. Utilizaram-se resultados das predições oceânicas de escala global da NOAA/NWS/NCEP (National Oceanic and Atmospheric Admistration, National Wether Service, National Center for Environmental Prediction, as três dos Estados Unidos da America) que tem como base o modelo numérico WAVEWATCH III (Tolman, 2002) que utiliza dados do NCEP para definir as condições fronteira para o modelo. Efectuou-se uma analise a longo prazo tanto do clima médio como extremo e estudaram-se quais as funções de distribuição de probabilidade para análise extrema (Lognormal, Exponencial, Weibull, Gumbel e Frechet) melhor se adaptam ao clima marítimo da região. Os resultados serão apresentados com o objectivo de compreender que condições de agitação marítimas devem ser utilizadas no dimensionamento de estruturas (para diferentes períodos de retorno) bem como para estudos relacionados com transporte de sedimentos. http://hdl.handle.net/2117/14343 Title: Estudo do comportamento hidráulico de estruturas marítimas com ondas longas: parte I Authors: Oliveira, Tiago Castro Alves; Sánchez-Arcilla Conejo, Agustín; Gironella Cobos, Xavier Abstract: Neste trabalho é implementado e validado a geração de ondas longas num canal numérico de ondas. Funções de transferências utilizadas em canais físicos para gerar ondas longas de forma constante são aplicadas com sucesso a um canal numérico baseado no método PFEM. Resultados de ensaios em canal físico são utilizados para validar a geração de ondas “espúrias” no canal numérico aquando da utilização de uma função de transferência baseada na teoria linear de onda. Os resultados obtidos indicam que as teorias de geração implementadas permitem poder abordar de forma correta a simulação da interação entre ondas regulares longas e estruturas marítimas num canal numérico baseado no método PFEM. Wed, 28 Dec 2011 18:55:01 GMT http://hdl.handle.net/2117/14343 2011-12-28T18:55:01Z Oliveira, Tiago Castro Alves; Sánchez-Arcilla Conejo, Agustín; Gironella Cobos, Xavier no Neste trabalho é implementado e validado a geração de ondas longas num canal numérico de ondas. Funções de transferências utilizadas em canais físicos para gerar ondas longas de forma constante são aplicadas com sucesso a um canal numérico baseado no método PFEM. Resultados de ensaios em canal físico são utilizados para validar a geração de ondas “espúrias” no canal numérico aquando da utilização de uma função de transferência baseada na teoria linear de onda. Os resultados obtidos indicam que as teorias de geração implementadas permitem poder abordar de forma correta a simulação da interação entre ondas regulares longas e estruturas marítimas num canal numérico baseado no método PFEM. http://hdl.handle.net/2117/12783 Title: Pluviometric regionalization of Catalunya: a compositional data methodology Authors: Gibergans Baguena, José; Ortego Martínez, María Isabel; Tolosana Delgado, Raimon Abstract: The aim of this paper is to introduce a methodology for de¯ning groups from regionalized com- positional data, through a hierarchical clustering algorithm aware of both the spatial dependence and the compositional character of the data set. This method is used to de¯ne a regionalization of Catalunya (NE Spain) with respect to its precipitation patterns in the Winter season. This region is characterized by a highly contrasted topography, which plays a dominant role in the spatial distribution of precipitation. Each rain gauge station is characterized by the relative frequencies of occurrence of six intervals of daily precipitation amount (classes ranging from \no rain" for precipitation below 3 mm, to \heavy storm" above 50 mm). Recognizing that frequencies are com-positional data, the spatial dependence of this data set has been characterized by variograms of the set of all pair-wise log-ratios, in the fashion of the variation matrix. Then, a Mahalanobis distance between stations has been de¯ned using these variograms to ensure that gauges with high spatial correlation get smaller distances. This spatially-dependent distance criterion has been used in a Ward hierarhical cluster method to de¯ne the regions. Results reveal 5 quite homogeneous groups of stations, which can be mostly ascribed a physical meaning. Finally, possible links to regional circulation patterns are discussed. Thu, 16 Jun 2011 08:58:20 GMT http://hdl.handle.net/2117/12783 2011-06-16T08:58:20Z Gibergans Baguena, José; Ortego Martínez, María Isabel; Tolosana Delgado, Raimon no The aim of this paper is to introduce a methodology for de¯ning groups from regionalized com- positional data, through a hierarchical clustering algorithm aware of both the spatial dependence and the compositional character of the data set. This method is used to de¯ne a regionalization of Catalunya (NE Spain) with respect to its precipitation patterns in the Winter season. This region is characterized by a highly contrasted topography, which plays a dominant role in the spatial distribution of precipitation. Each rain gauge station is characterized by the relative frequencies of occurrence of six intervals of daily precipitation amount (classes ranging from \no rain" for precipitation below 3 mm, to \heavy storm" above 50 mm). Recognizing that frequencies are com-positional data, the spatial dependence of this data set has been characterized by variograms of the set of all pair-wise log-ratios, in the fashion of the variation matrix. Then, a Mahalanobis distance between stations has been de¯ned using these variograms to ensure that gauges with high spatial correlation get smaller distances. This spatially-dependent distance criterion has been used in a Ward hierarhical cluster method to de¯ne the regions. Results reveal 5 quite homogeneous groups of stations, which can be mostly ascribed a physical meaning. Finally, possible links to regional circulation patterns are discussed. http://hdl.handle.net/2117/12670 Title: Trend analysis of the wave storminess: the wave direction Authors: Casas Prat, Mercè; Sierra Pedrico, Juan Pablo Abstract: In this paper changes in the wave pattern of the Catalan coast are analyzed in terms of wave storminess and wave direction based on series of 44 years of hindcast wave data. The analysis is performed employing two different techniques: one resulting from the combination of regression and bootstrapping and the other applying a Bayesian method. Although the trends are, in general, null, in some locations there are clear changes in the wave directional frequencies. These changes can significatively affect coastal hydrodynamics and morphodynamics. Mon, 30 May 2011 12:05:32 GMT http://hdl.handle.net/2117/12670 2011-05-30T12:05:32Z Casas Prat, Mercè; Sierra Pedrico, Juan Pablo no In this paper changes in the wave pattern of the Catalan coast are analyzed in terms of wave storminess and wave direction based on series of 44 years of hindcast wave data. The analysis is performed employing two different techniques: one resulting from the combination of regression and bootstrapping and the other applying a Bayesian method. Although the trends are, in general, null, in some locations there are clear changes in the wave directional frequencies. These changes can significatively affect coastal hydrodynamics and morphodynamics.