http://hdl.handle.net/2117/3505 Sat, 25 May 2013 17:52:59 GMT 2013-05-25T17:52:59Z webmaster.bupc@upc.edu Universitat Politècnica de Catalunya. Servei de Biblioteques i Documentació no http://hdl.handle.net/2117/17140 Title: Lagrangian simulation of suspended sediment in the swash zone Authors: Alsina Torrent, José Maria; Cáceres Rabionet, Iván; Sospedra Iglesias, Joaquim; Baldock, Tom E. Abstract: A numerical model is presented to simulate the sediment transport and beach morphology in the swash zone. The model resolves the non-linear shallow water equations in an Eulerian framework and then solves the advection-diffusion equation for turbulence and suspended sediment in a Lagrangian framework. A laboratory experimental data set under solitary broken waves has been used to validate the model ability to simulate the sediment mass trapped at different cross-shore positions. The model shows very good fit to experimental data illustrating the importance of sediment advection to predict correctly the sediment transport in the swash zone. Numerical simulations of a swash event in a natural beach show that sediment advection controls the cross-shore sediment transport distribution which is important to give realistic bed level evolution Mon, 17 Dec 2012 16:52:40 GMT http://hdl.handle.net/2117/17140 2012-12-17T16:52:40Z Alsina Torrent, José Maria; Cáceres Rabionet, Iván; Sospedra Iglesias, Joaquim; Baldock, Tom E. no A numerical model is presented to simulate the sediment transport and beach morphology in the swash zone. The model resolves the non-linear shallow water equations in an Eulerian framework and then solves the advection-diffusion equation for turbulence and suspended sediment in a Lagrangian framework. A laboratory experimental data set under solitary broken waves has been used to validate the model ability to simulate the sediment mass trapped at different cross-shore positions. The model shows very good fit to experimental data illustrating the importance of sediment advection to predict correctly the sediment transport in the swash zone. Numerical simulations of a swash event in a natural beach show that sediment advection controls the cross-shore sediment transport distribution which is important to give realistic bed level evolution http://hdl.handle.net/2117/16973 Title: Wave and flow response to an artificial surf reef: laboratory measurements Authors: Cáceres Rabionet, Iván; Trung, Le Hai; van Ettinger, Hendrik Dirk; Reniers, Ad; Uijttewaal, Wim Abstract: Waves and currents are essential elements in the design of an artificial surfing reef ASR. ASRs are primarily designed to optimize the surfing conditions i.e., increase the surfability of the incoming waves possibly in combination with the shoreline protection from erosion. The currents generated by waves breaking on the ASR play an important role in the surfability through the wave-current interaction WCI . Depending on the design, the WCI may negatively affect the surfability by causing the waves to break prematurely due to the current-induced wave steepening. In addition, wave breaking tends to become more irregular due to the temporal variability of the underlying currents. To mitigate the negative effects of wave breaking induced currents on the surfability, three ASR layouts are examined through detailed laboratory experiments. The layouts differ in the alongshore separation distance between two symmetrical reef sides. The ensuing flow circulations are examined in detail with both in situ current meters and video observations of surface drifters. This is done for regular incident waves, bichromatic incident waves, and irregular incident waves, all with equal energy. A data analysis shows that for a given layout the mean flow patterns for regular, bichromatic, and irregular waves are qualitatively similar, with oblique rip currents exiting at either side of the reef and strong flow circulations onshore of the gap in between the two reef sides. Increasing the separation distance leads to a significant reduction of the obliquely exiting rip currents at the outer sides of the reef, but an increase in the flow circulation onshore of the gap. This has a positive effect on the surfability by reducing the negative effects associated with the WCI on the wave breaking, thus, providing longer rides. Tue, 20 Nov 2012 11:50:15 GMT http://hdl.handle.net/2117/16973 2012-11-20T11:50:15Z Cáceres Rabionet, Iván; Trung, Le Hai; van Ettinger, Hendrik Dirk; Reniers, Ad; Uijttewaal, Wim no Waves and currents are essential elements in the design of an artificial surfing reef ASR. ASRs are primarily designed to optimize the surfing conditions i.e., increase the surfability of the incoming waves possibly in combination with the shoreline protection from erosion. The currents generated by waves breaking on the ASR play an important role in the surfability through the wave-current interaction WCI . Depending on the design, the WCI may negatively affect the surfability by causing the waves to break prematurely due to the current-induced wave steepening. In addition, wave breaking tends to become more irregular due to the temporal variability of the underlying currents. To mitigate the negative effects of wave breaking induced currents on the surfability, three ASR layouts are examined through detailed laboratory experiments. The layouts differ in the alongshore separation distance between two symmetrical reef sides. The ensuing flow circulations are examined in detail with both in situ current meters and video observations of surface drifters. This is done for regular incident waves, bichromatic incident waves, and irregular incident waves, all with equal energy. A data analysis shows that for a given layout the mean flow patterns for regular, bichromatic, and irregular waves are qualitatively similar, with oblique rip currents exiting at either side of the reef and strong flow circulations onshore of the gap in between the two reef sides. Increasing the separation distance leads to a significant reduction of the obliquely exiting rip currents at the outer sides of the reef, but an increase in the flow circulation onshore of the gap. This has a positive effect on the surfability by reducing the negative effects associated with the WCI on the wave breaking, thus, providing longer rides. http://hdl.handle.net/2117/16958 Title: Wave field behind impermeable low crested structures Authors: Buccino, Mariano; Vicinanza, Diego; Cáceres Rabionet, Iván; Calabrese, Mario Abstract: Hydraulic performance of Low Crested Structures have been widely studied both theoretically and through experimental analyses; yet, only few indications are available on the interaction between the main transmission modes (overtopping, filtration) and wave diffraction. Starting from the analysis of hydraulic model tests conducted at the 3D wave basin of Delft University of Technology, the paper investigates the spatial distribution of the transmitted wave energy due to both wave overtopping and diffraction, and discusses the corresponding change of the power spectrum functions Mon, 19 Nov 2012 17:03:25 GMT http://hdl.handle.net/2117/16958 2012-11-19T17:03:25Z Buccino, Mariano; Vicinanza, Diego; Cáceres Rabionet, Iván; Calabrese, Mario no Hydraulic performance of Low Crested Structures have been widely studied both theoretically and through experimental analyses; yet, only few indications are available on the interaction between the main transmission modes (overtopping, filtration) and wave diffraction. Starting from the analysis of hydraulic model tests conducted at the 3D wave basin of Delft University of Technology, the paper investigates the spatial distribution of the transmitted wave energy due to both wave overtopping and diffraction, and discusses the corresponding change of the power spectrum functions http://hdl.handle.net/2117/15841 Title: Sources of contamination and modelled pollutant trajectories in a Mediterranean harbour (Tarragona, Spain) Authors: Mestres Ridge, Marc; Sierra Pedrico, Juan Pablo; Mösso Aranda, César; Sánchez-Arcilla Conejo, Agustín Abstract: The proximity of commercial harbours to residential areas and the growing environmental awareness of society have led most port authorities to include environmental management within their administration plan. Regarding water quality, it is necessary to have the capacity and tools to deal with contamination episodes that may damage marine ecosystems and human health, but also affect the normal functioning of harbours. This paper presents a description of the main pollutant sources in Tarragona Harbour (Spain), and a numerical analysis of several pollution episodes based on the Port Authority’s actual environmental concerns. The results show that pollution generated inside the harbour tends to remain confined within the port, whereas it is very likely that oil spills from a nearby monobuoy may affect the neighbouring beaches. The present combination of numerical models proves itself a useful tool to assess the environmental risk associated to harbour activities and potential pollution spills. Fri, 11 May 2012 18:39:29 GMT http://hdl.handle.net/2117/15841 2012-05-11T18:39:29Z Mestres Ridge, Marc; Sierra Pedrico, Juan Pablo; Mösso Aranda, César; Sánchez-Arcilla Conejo, Agustín no Water pollution, Numerical models, Risk management, Harbours, Tarragona The proximity of commercial harbours to residential areas and the growing environmental awareness of society have led most port authorities to include environmental management within their administration plan. Regarding water quality, it is necessary to have the capacity and tools to deal with contamination episodes that may damage marine ecosystems and human health, but also affect the normal functioning of harbours. This paper presents a description of the main pollutant sources in Tarragona Harbour (Spain), and a numerical analysis of several pollution episodes based on the Port Authority’s actual environmental concerns. The results show that pollution generated inside the harbour tends to remain confined within the port, whereas it is very likely that oil spills from a nearby monobuoy may affect the neighbouring beaches. The present combination of numerical models proves itself a useful tool to assess the environmental risk associated to harbour activities and potential pollution spills. http://hdl.handle.net/2117/15686 Title: Guía para el análisis espacial de datos composicionales Authors: Tolosana Delgado, Raimon Abstract: El tratamiento de bases de datos composicionales (proporciones, porcentajes, concentraciones, etc.) con dependencia espacial debe hacerse atendiendo a las características matemáticas de éstos: una composición válida debe tener todas las componentes positivas y su suma debe ser igual o menor a un total (1, 100%, etc.). En general, esto se consigue de forma razonablemente fácil transformando la composición mediante series de log-cocientes de componentes. Para estudiar la variabilidad espacial de una composición se recomienda estimar y modelar el variaciograma: el conjunto de variogramas de todos los log-cocientes de un par de componentes. El variaciograma contiene toda la información necesaria para caracterizar una composición con estacionaridad intrínseca, y se puede modelar con herramientas habituales de la geoestadística, como el modelo de coregionalización lineal. Además, se pueden estudiar las propiedades del modelo e inferir relaciones entre componentes y posibles procesos vinculados a alguna escala espacial concreta. Finalmente, interpolar la composición y generar mapas es tarea sencilla con las herramientas existentes de krigeado y simulación: estas técnicas y conceptos deben aplicarse a un conjunto de log-cocientes cualquiera, tal que exista una transformación invertible entre éllos y las componentes de la composición original. Dealing with spatially-dependent compositional databases (including proportions, data in percentages, concentrations etc) should pay heed to the mathematical properties of these kinds of data: a valid composition must have positive components whose sum is at most a constant (1, 100% etc.). Generally speaking this is easily done by working on a set of log-ratios of components rather than using the raw data. To study the spatial variability of these databases it is best to estimate and model the lr-variograms, i.e. the set of variograms of all possible pairwise log-ratios of components in the composition. Such lr-variograms contain all the information necessary to deal with intrinsic stationary compositions and may be modelled with standard geostatistical tools such as the linear model of coregionalization. Moreover, the properties of the model can be studied and relationships inferred between components and possible processes linked to a given spatial scale. Finally, component-by-component interpolation and mapping is straightforward with existing kriging and simulation techniques: these tools and concepts should be applied to any set of invertible component log-ratios, i.e. log-ratio transformations, in such a way that the original composition can be recovered from the transformed data and vice versa. Wed, 28 Mar 2012 17:45:31 GMT http://hdl.handle.net/2117/15686 2012-03-28T17:45:31Z Tolosana Delgado, Raimon no covariance function, simplex, composición, función de covarianza, geometría de Aitchison, símplex, Aitchison geometry, composition El tratamiento de bases de datos composicionales (proporciones, porcentajes, concentraciones, etc.) con dependencia espacial debe hacerse atendiendo a las características matemáticas de éstos: una composición válida debe tener todas las componentes positivas y su suma debe ser igual o menor a un total (1, 100%, etc.). En general, esto se consigue de forma razonablemente fácil transformando la composición mediante series de log-cocientes de componentes. Para estudiar la variabilidad espacial de una composición se recomienda estimar y modelar el variaciograma: el conjunto de variogramas de todos los log-cocientes de un par de componentes. El variaciograma contiene toda la información necesaria para caracterizar una composición con estacionaridad intrínseca, y se puede modelar con herramientas habituales de la geoestadística, como el modelo de coregionalización lineal. Además, se pueden estudiar las propiedades del modelo e inferir relaciones entre componentes y posibles procesos vinculados a alguna escala espacial concreta. Finalmente, interpolar la composición y generar mapas es tarea sencilla con las herramientas existentes de krigeado y simulación: estas técnicas y conceptos deben aplicarse a un conjunto de log-cocientes cualquiera, tal que exista una transformación invertible entre éllos y las componentes de la composición original. Dealing with spatially-dependent compositional databases (including proportions, data in percentages, concentrations etc) should pay heed to the mathematical properties of these kinds of data: a valid composition must have positive components whose sum is at most a constant (1, 100% etc.). Generally speaking this is easily done by working on a set of log-ratios of components rather than using the raw data. To study the spatial variability of these databases it is best to estimate and model the lr-variograms, i.e. the set of variograms of all possible pairwise log-ratios of components in the composition. Such lr-variograms contain all the information necessary to deal with intrinsic stationary compositions and may be modelled with standard geostatistical tools such as the linear model of coregionalization. Moreover, the properties of the model can be studied and relationships inferred between components and possible processes linked to a given spatial scale. Finally, component-by-component interpolation and mapping is straightforward with existing kriging and simulation techniques: these tools and concepts should be applied to any set of invertible component log-ratios, i.e. log-ratio transformations, in such a way that the original composition can be recovered from the transformed data and vice versa. http://hdl.handle.net/2117/14979 Title: The new pelagic operational observatory of the catalan sea (OOCS) for the multisensor coordinated measurement of atmospheric and oceanographic conditions Authors: Cruzado, Antonio; Bahamón Rivera, Nixon; Aguzzi, Jacopo; Bernardello, Raffaele; Ahumada Sempoal, Miguel Angel; Puigdefàbregas Sagristà, Joan; Cateura Sabrí, Jordi; Muñoz, Eduardo; Velasquez Forero, Zoila Abstract: The new pelagic Operational Observatory of the Catalan Sea (OOCS) for the coordinated multisensor measurement of atmospheric and oceanographic conditions has been recently installed (2009) in the Catalan Sea (41°39'N, 2°54'E; Western Mediterranean) and continuously operated (with minor maintenance gaps) until today. This multiparametric platform is moored at 192 m depth, 9.3 km off Blanes harbour (Girona, Spain). It is composed of a buoy holding atmospheric sensors and a set of oceanographic sensors measuring the water conditions over the upper 100 m depth. The station is located close to the head of the Blanes submarine canyon where an important multispecies pelagic and demersal fishery gives the station ecological and economic relevance. The OOCS provides important records on atmospheric and oceanographic conditions, the latter through the measurement of hydrological and biogeochemical parameters, at depths with a time resolution never attained before for this area of the Mediterranean. Twenty four moored sensors and probes operating in a coordinated fashion provide important data on Essential Ocean Variables (EOVs; UNESCO) such as temperature, salinity, pressure, dissolved oxygen, chlorophyll fluorescence, and turbidity. In comparison with other pelagic observatories presently operating in other world areas, OOCS also measures photosynthetic available radiation (PAR) from above the sea surface and at different depths in the upper 50 m. Data are recorded each 30 min and transmitted in real-time to a ground station via GPRS. This time series is published and automatically updated at the frequency of data collection on the official OOCS website (http://www.ceab.csic.es/~oceans). Under development are embedded automated routines for the in situ data treatment and assimilation into numerical models, in order to provide a reliable local marine processing forecast. In this work, our goal is to detail the OOCS multisensor architecture in relation to the coordinated capability for the remote, continuous and prolonged monitoring of atmospheric and oceanographic conditions, including data communication and storage. Accordingly, time series of measurements for a number of biological parameters will be presented for the summer months of 2011. Marine hindcast outputs from the numerical models implemented for simulating the conditions over the study area are shown. The strong changes of atmospheric conditions recorded in the last years over the area have altered the marine conditions of living organisms, but the dimension of the impact remains unclear. The OOCS multisensor coordinated monitoring has been specifically designed to address this issue, thus contributing to better understand the present environmental fluctuations and to provide a sound basis for a more accurate marine forecast system. Mon, 06 Feb 2012 15:06:01 GMT http://hdl.handle.net/2117/14979 2012-02-06T15:06:01Z Cruzado, Antonio; Bahamón Rivera, Nixon; Aguzzi, Jacopo; Bernardello, Raffaele; Ahumada Sempoal, Miguel Angel; Puigdefàbregas Sagristà, Joan; Cateura Sabrí, Jordi; Muñoz, Eduardo; Velasquez Forero, Zoila no Pelagic observatory, Oceanographic buoy, Multisensor coordinated monitoring, PAR, Operational oceanography, Submarine canyons, Numerical multiparametric modelling, Ocean forecast, Western Mediterranean Sea The new pelagic Operational Observatory of the Catalan Sea (OOCS) for the coordinated multisensor measurement of atmospheric and oceanographic conditions has been recently installed (2009) in the Catalan Sea (41°39'N, 2°54'E; Western Mediterranean) and continuously operated (with minor maintenance gaps) until today. This multiparametric platform is moored at 192 m depth, 9.3 km off Blanes harbour (Girona, Spain). It is composed of a buoy holding atmospheric sensors and a set of oceanographic sensors measuring the water conditions over the upper 100 m depth. The station is located close to the head of the Blanes submarine canyon where an important multispecies pelagic and demersal fishery gives the station ecological and economic relevance. The OOCS provides important records on atmospheric and oceanographic conditions, the latter through the measurement of hydrological and biogeochemical parameters, at depths with a time resolution never attained before for this area of the Mediterranean. Twenty four moored sensors and probes operating in a coordinated fashion provide important data on Essential Ocean Variables (EOVs; UNESCO) such as temperature, salinity, pressure, dissolved oxygen, chlorophyll fluorescence, and turbidity. In comparison with other pelagic observatories presently operating in other world areas, OOCS also measures photosynthetic available radiation (PAR) from above the sea surface and at different depths in the upper 50 m. Data are recorded each 30 min and transmitted in real-time to a ground station via GPRS. This time series is published and automatically updated at the frequency of data collection on the official OOCS website (http://www.ceab.csic.es/~oceans). Under development are embedded automated routines for the in situ data treatment and assimilation into numerical models, in order to provide a reliable local marine processing forecast. In this work, our goal is to detail the OOCS multisensor architecture in relation to the coordinated capability for the remote, continuous and prolonged monitoring of atmospheric and oceanographic conditions, including data communication and storage. Accordingly, time series of measurements for a number of biological parameters will be presented for the summer months of 2011. Marine hindcast outputs from the numerical models implemented for simulating the conditions over the study area are shown. The strong changes of atmospheric conditions recorded in the last years over the area have altered the marine conditions of living organisms, but the dimension of the impact remains unclear. The OOCS multisensor coordinated monitoring has been specifically designed to address this issue, thus contributing to better understand the present environmental fluctuations and to provide a sound basis for a more accurate marine forecast system. http://hdl.handle.net/2117/14774 Title: Playas agotadas Authors: Jiménez Quintana, José Antonio Abstract: Impedimos el aporte de sedimentos y alteramos la dinámica natural costera. ¿Y todavía nos extraña que las playas se hallen en retroceso? Tue, 24 Jan 2012 14:38:33 GMT http://hdl.handle.net/2117/14774 2012-01-24T14:38:33Z Jiménez Quintana, José Antonio no Impedimos el aporte de sedimentos y alteramos la dinámica natural costera. ¿Y todavía nos extraña que las playas se hallen en retroceso? http://hdl.handle.net/2117/14758 Title: Future scenario simulations of wave climate in the NW Mediterranean sea Authors: Casas Prat, Mercè; Sierra Pedrico, Juan Pablo Abstract: In this study, 20-year wave climate simulations (1991-2010 and 2081-2100) were performed and analysed in the NW Mediterranean with a fine resolution of 1/8º. The forcing wind was obtained from the ENSEMBLES project, including 3-hourly resolution, daily mean and maximum winds. The validation of the reference situation was done by comparing the probability density function of the datasets. It showed a reasonable agreement between results from 3-hourly winds and buoy data and between results from daily mean wind and wave hindcast data, although the spreading of the distribution is underestimated and some spatial discrepancies were found. The general tendency of the mean significant wave height is to decrease with the exception of the Northern Catalan coast for which no significant variation was detected. A seasonal analysis revealed a change in the annual pattern. During spring and summer the mean significant wave height tends to increase in some areas whereas milder winter and autumn periods are expected. The analysis of the 95% cumulative significant wave height showed similar results but accentuated changes were found. Tue, 24 Jan 2012 09:14:50 GMT http://hdl.handle.net/2117/14758 2012-01-24T09:14:50Z Casas Prat, Mercè; Sierra Pedrico, Juan Pablo no In this study, 20-year wave climate simulations (1991-2010 and 2081-2100) were performed and analysed in the NW Mediterranean with a fine resolution of 1/8º. The forcing wind was obtained from the ENSEMBLES project, including 3-hourly resolution, daily mean and maximum winds. The validation of the reference situation was done by comparing the probability density function of the datasets. It showed a reasonable agreement between results from 3-hourly winds and buoy data and between results from daily mean wind and wave hindcast data, although the spreading of the distribution is underestimated and some spatial discrepancies were found. The general tendency of the mean significant wave height is to decrease with the exception of the Northern Catalan coast for which no significant variation was detected. A seasonal analysis revealed a change in the annual pattern. During spring and summer the mean significant wave height tends to increase in some areas whereas milder winter and autumn periods are expected. The analysis of the 95% cumulative significant wave height showed similar results but accentuated changes were found. http://hdl.handle.net/2117/14662 Title: Composite modelling of interactions between beaches and structures Authors: Gerritsen, Herman; Sutherland, James; Deigaard, Rolf; Sumer, Multlu; Fortes, C.J.E.M.; Sierra Pedrico, Juan Pablo; Schmidtke, Ulrike Abstract: An overview of Composite Modelling (CM) is presented, as elaborated in the EU/HYDRALAB joint research project Composite Modelling of the Interactions Between Beaches and Structures. An introduction and a review of the main literature on CM in the hydraulic community are given. In Section 3, the case studies of CM of the seven partners participating in this project are discussed. The focus is on the methodologies used and their impact on the modelling approach, rather than the results of the experiments per se. A further section presents reflections on key elements in CM, as they emerged in the various case studies. The related subject of Good Modelling Practice is summarized in Section 5. Then guidelines are given on how to decide if CM may be beneficial, and how to set up a CM experiment. It is concluded that CM in the hydraulic community is still in its infancy but involves challenging research with significant potential. Wed, 18 Jan 2012 18:09:15 GMT http://hdl.handle.net/2117/14662 2012-01-18T18:09:15Z Gerritsen, Herman; Sutherland, James; Deigaard, Rolf; Sumer, Multlu; Fortes, C.J.E.M.; Sierra Pedrico, Juan Pablo; Schmidtke, Ulrike no An overview of Composite Modelling (CM) is presented, as elaborated in the EU/HYDRALAB joint research project Composite Modelling of the Interactions Between Beaches and Structures. An introduction and a review of the main literature on CM in the hydraulic community are given. In Section 3, the case studies of CM of the seven partners participating in this project are discussed. The focus is on the methodologies used and their impact on the modelling approach, rather than the results of the experiments per se. A further section presents reflections on key elements in CM, as they emerged in the various case studies. The related subject of Good Modelling Practice is summarized in Section 5. Then guidelines are given on how to decide if CM may be beneficial, and how to set up a CM experiment. It is concluded that CM in the hydraulic community is still in its infancy but involves challenging research with significant potential. http://hdl.handle.net/2117/14459 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. Tue, 10 Jan 2012 19:12:12 GMT http://hdl.handle.net/2117/14459 2012-01-10T19:12:12Z Mösso Aranda, César; Sierra Pedrico, Juan Pablo; Gracia Garcia, Vicente; Mestres Ridge, Marc; Rodríguez Allende, Andrés no 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/2117/13138 Title: Probabilistic coastal vulnerability assessment to storms at regional scale : application to Catalan beaches (NW Mediterranean) Authors: Bosom García, Eva; Jiménez Quintana, José Antonio Abstract: A methodology to assess storm-induced coastal vulnerability taking into account the different induced processes separately (inundation and erosion) is presented. It is based on a probabilistic approach where hazards time series are built from existing storm data and later used to fit an extreme probability function. This is done for different sectors along the coast defined in terms of the wave climate and for representative beach types of the area to be analyzed. Once probability distributions are available, coastal managers must decide the probability of occurrence to be accepted as well as the period of concern of the analysis in function of the importance of the hinterland. These two variables will determine the return period to be considered in the assessment. The comparison of hazards and vulnerabilities associated with the selected probability of occurrence permit to identify the most hazardous areas along the coast in a robust manner by including the spatial variability in forcing (storm climate) and receptor (beaches). The methodology has been applied to a 50 km long coastal stretch of the Catalonia (NW Mediterranean) where offshore wave conditions can be assumed to be homogeneous. In spite of this spatially constant wave field, obtained results indicate a large variability in hazards intensity and vulnerability along the coast. Mon, 29 Aug 2011 22:00:30 GMT http://hdl.handle.net/2117/13138 2011-08-29T22:00:30Z Bosom García, Eva; Jiménez Quintana, José Antonio no A methodology to assess storm-induced coastal vulnerability taking into account the different induced processes separately (inundation and erosion) is presented. It is based on a probabilistic approach where hazards time series are built from existing storm data and later used to fit an extreme probability function. This is done for different sectors along the coast defined in terms of the wave climate and for representative beach types of the area to be analyzed. Once probability distributions are available, coastal managers must decide the probability of occurrence to be accepted as well as the period of concern of the analysis in function of the importance of the hinterland. These two variables will determine the return period to be considered in the assessment. The comparison of hazards and vulnerabilities associated with the selected probability of occurrence permit to identify the most hazardous areas along the coast in a robust manner by including the spatial variability in forcing (storm climate) and receptor (beaches). The methodology has been applied to a 50 km long coastal stretch of the Catalonia (NW Mediterranean) where offshore wave conditions can be assumed to be homogeneous. In spite of this spatially constant wave field, obtained results indicate a large variability in hazards intensity and vulnerability along the coast. http://hdl.handle.net/2117/13111 Title: Sediment suspension events in the inner surf and swash zone. Measurements in large-scale and high-energy wave conditions Authors: Alsina, José M.; Cáceres Rabionet, Iván Abstract: The present study presents a database of hydrodynamic properties and suspended sediment concentration collected within the inner surf and swash zones aiming to improve the current understanding of the sediment dynamics occurring within the beach area closest to the shoreline. Experimental measurements were conducted in a large-scale wave flume under high-energy wave conditions at three cross-shore locations, representing inner surf and swash zone conditions. 47 tests, each one comprising 500 wave trains with identical wave conditions were measured. Obtained hydrodynamic properties and suspended sediment concentrations were observed to be highly repeatable between successive tests despite the sediment suspension event-like pattern, the beach evolution between tests, and the apparent randomness of the sediment suspension phenomenon. The hydrodynamics close to the shoreline (inner surf and swash zone) is dominated by short incident broken waves and long-wave water level oscillations induced by wave grouping. The analyzed time series of measured water surface elevation, horizontal velocity, computed Turbulent Kinetic Energy (TKE), and sediment concentration revealed that the suspended sediment concentration in this coastal zone does not correlate strongly with either the incident bore height, or the short-wave horizontal velocity or the TKE; in other words high/low values of these variables do not always promote high/low values of sediment suspension. In contrast, the highest suspended sediment concentrations were observed to occur by the combined action of incident bores and the trough of long-period water level oscillations. This pattern was more apparent in the inner surf than in the swash zone. High suspended sediment concentrations were also observed to coincide with negative peaks in long-wave horizontal velocity modulation resulting in enhanced negative sediment transport rates and beach erosion close to the shoreline. Thu, 25 Aug 2011 10:16:11 GMT http://hdl.handle.net/2117/13111 2011-08-25T10:16:11Z Alsina, José M.; Cáceres Rabionet, Iván no The present study presents a database of hydrodynamic properties and suspended sediment concentration collected within the inner surf and swash zones aiming to improve the current understanding of the sediment dynamics occurring within the beach area closest to the shoreline. Experimental measurements were conducted in a large-scale wave flume under high-energy wave conditions at three cross-shore locations, representing inner surf and swash zone conditions. 47 tests, each one comprising 500 wave trains with identical wave conditions were measured. Obtained hydrodynamic properties and suspended sediment concentrations were observed to be highly repeatable between successive tests despite the sediment suspension event-like pattern, the beach evolution between tests, and the apparent randomness of the sediment suspension phenomenon. The hydrodynamics close to the shoreline (inner surf and swash zone) is dominated by short incident broken waves and long-wave water level oscillations induced by wave grouping. The analyzed time series of measured water surface elevation, horizontal velocity, computed Turbulent Kinetic Energy (TKE), and sediment concentration revealed that the suspended sediment concentration in this coastal zone does not correlate strongly with either the incident bore height, or the short-wave horizontal velocity or the TKE; in other words high/low values of these variables do not always promote high/low values of sediment suspension. In contrast, the highest suspended sediment concentrations were observed to occur by the combined action of incident bores and the trough of long-period water level oscillations. This pattern was more apparent in the inner surf than in the swash zone. High suspended sediment concentrations were also observed to coincide with negative peaks in long-wave horizontal velocity modulation resulting in enhanced negative sediment transport rates and beach erosion close to the shoreline. http://hdl.handle.net/2117/12489 Title: Wave height data assimilation using non-stationary kriging Authors: Tolosana Delgado, Raimon; Egozcue Rubí, Juan José; Sánchez-Arcilla Conejo, Agustín; Gómez Aguar, Jesús Javier Abstract: Data assimilation into numerical models should be both computationally fast and physically meaningful, in order to be applicable in online environmental surveillance. We present a way to improve assimilation for computationally intensive models, based on non-stationary kriging and a separable space–time covariance function. The method is illustrated with significant wave height data. The covariance function is expressed as a collection of fields: each one is obtained as the empirical covariance between the studied property(significant wave height in log-scale)at a pixel where a measurement is located (a wave-buoy is available)and the same parameter at every other pixel of thef ield. These covariances are computed from the available history of forecasts. The method provides a set of weights, that can be mapped for each measuring location, and that do not vary with time. Resulting weights may be used in a weighted average of the differences between the forecast and measured parameter. In the case presented, these weights may show long-range connection patterns, such as between the Catalan coast and the eastern coast of Sardinia, associated to common prevailing meteo-oceanographic conditions. When such patterns are considered as non-informative of the present situation, it is always possible to diminish their influence by relaxing the covariance maps. Fri, 06 May 2011 08:06:38 GMT http://hdl.handle.net/2117/12489 2011-05-06T08:06:38Z Tolosana Delgado, Raimon; Egozcue Rubí, Juan José; Sánchez-Arcilla Conejo, Agustín; Gómez Aguar, Jesús Javier no Data assimilation into numerical models should be both computationally fast and physically meaningful, in order to be applicable in online environmental surveillance. We present a way to improve assimilation for computationally intensive models, based on non-stationary kriging and a separable space–time covariance function. The method is illustrated with significant wave height data. The covariance function is expressed as a collection of fields: each one is obtained as the empirical covariance between the studied property(significant wave height in log-scale)at a pixel where a measurement is located (a wave-buoy is available)and the same parameter at every other pixel of thef ield. These covariances are computed from the available history of forecasts. The method provides a set of weights, that can be mapped for each measuring location, and that do not vary with time. Resulting weights may be used in a weighted average of the differences between the forecast and measured parameter. In the case presented, these weights may show long-range connection patterns, such as between the Catalan coast and the eastern coast of Sardinia, associated to common prevailing meteo-oceanographic conditions. When such patterns are considered as non-informative of the present situation, it is always possible to diminish their influence by relaxing the covariance maps. http://hdl.handle.net/2117/11619 Title: Desarrollo de una herramienta operacional de control de la calidad del agua en zonas portuarias mediante simulación numérica y observaciones Authors: Sánchez-Arcilla Conejo, Agustín; Espino Infantes, Manuel; Sierra Pedrico, Juan Pablo; García Sotillo, Marcos; Álvarez Fanjul, Enrique; Romo, Javier; Solé, Xavier; Basora, Joan; Hernáez, Mario; Grifoll Colls, Manel; Jordà Sánchez, Gabriel Abstract: El trabajo que se presenta se desarrolló dentro de un Convenio de Colaboración entre Puertos del Estado, las AAPP de Barcelona, Tarragona y Bilbao y el Laboratorio de Ingeniería Marítima de la UPC (LIM/UPC) y es la base de un futuro sistema de control, previsión y diagnostico de la calidad del agua en zonas portuarias. El sistema, basado en un conjunto de modelos numéricos de circulación y dispersión actualmente en fase de desarrollo, permitirá analizar y predecir de manera continua la calidad del agua en zonas portuarias y aledañas, siendo de gran utilidad para la evaluación y minimización del impacto que las actividades portuarias puedan tener en el ecosistema circundante. El Sistema Portuario (SP) Español busca la implementación de una gestión de su actividad que permita aunar la mejora de servicios y el incremento de la competitividad con el aumento de la sostenibilidad de la propia actividad. Para alcanzar este objetivo doble, resulta indispensable que el SP adquiera un mayor conocimiento del medio en el que se desarrolla la actividad portuaria, para todo lo cual herramientas y sistemas como el aquí presentado juegan un papel clave. Wed, 02 Mar 2011 08:54:09 GMT http://hdl.handle.net/2117/11619 2011-03-02T08:54:09Z Sánchez-Arcilla Conejo, Agustín; Espino Infantes, Manuel; Sierra Pedrico, Juan Pablo; García Sotillo, Marcos; Álvarez Fanjul, Enrique; Romo, Javier; Solé, Xavier; Basora, Joan; Hernáez, Mario; Grifoll Colls, Manel; Jordà Sánchez, Gabriel no El trabajo que se presenta se desarrolló dentro de un Convenio de Colaboración entre Puertos del Estado, las AAPP de Barcelona, Tarragona y Bilbao y el Laboratorio de Ingeniería Marítima de la UPC (LIM/UPC) y es la base de un futuro sistema de control, previsión y diagnostico de la calidad del agua en zonas portuarias. El sistema, basado en un conjunto de modelos numéricos de circulación y dispersión actualmente en fase de desarrollo, permitirá analizar y predecir de manera continua la calidad del agua en zonas portuarias y aledañas, siendo de gran utilidad para la evaluación y minimización del impacto que las actividades portuarias puedan tener en el ecosistema circundante. El Sistema Portuario (SP) Español busca la implementación de una gestión de su actividad que permita aunar la mejora de servicios y el incremento de la competitividad con el aumento de la sostenibilidad de la propia actividad. Para alcanzar este objetivo doble, resulta indispensable que el SP adquiera un mayor conocimiento del medio en el que se desarrolla la actividad portuaria, para todo lo cual herramientas y sistemas como el aquí presentado juegan un papel clave. http://hdl.handle.net/2117/11130 Title: Storm-induced coastal hazard assessment at regional scale: application to Catalonia (NW Mediterranean) Authors: Bosom García, Eva; Jiménez Quintana, José Antonio Abstract: A methodology for coastal hazard assessment at regional scale is presented and applied to the Catalan coast (NW Mediterranean). The method separately evaluates erosion and inundation hazards by using wave time series and beach characteristics (slope and sediment grain size). Obtained hazard time series are fitted to extreme probability distributions for different coastal sectors which are defined in function of local wave climate. This approach allows to compare the spatial variation of hazard intensities for a given probability of occurrence and, thus, to objectively identify the most hazardous areas along the coast in terms of erosion and inundation. Obtained results indicate that the coast north of Barcelona is more hazardous than the southern coast regarding inundation for any given probability. With respect to storm-induced erosion, the central coast of Catalonia is the less hazardous area, although spatial variations in erosion along the coast are smaller than the observed for inundation. Thu, 20 Jan 2011 15:45:57 GMT http://hdl.handle.net/2117/11130 2011-01-20T15:45:57Z Bosom García, Eva; Jiménez Quintana, José Antonio no A methodology for coastal hazard assessment at regional scale is presented and applied to the Catalan coast (NW Mediterranean). The method separately evaluates erosion and inundation hazards by using wave time series and beach characteristics (slope and sediment grain size). Obtained hazard time series are fitted to extreme probability distributions for different coastal sectors which are defined in function of local wave climate. This approach allows to compare the spatial variation of hazard intensities for a given probability of occurrence and, thus, to objectively identify the most hazardous areas along the coast in terms of erosion and inundation. Obtained results indicate that the coast north of Barcelona is more hazardous than the southern coast regarding inundation for any given probability. With respect to storm-induced erosion, the central coast of Catalonia is the less hazardous area, although spatial variations in erosion along the coast are smaller than the observed for inundation.