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Sea level rise, a consequence of climate change, is one of the biggest challenges that countries and regions with coastal lowlands will face in the medium term. This study proposes a methodology for assessing the vulnerability to sea-level rise on the Atlantic coast of mainland Portugal. Some scenarios of extreme sea levels for different return periods and extreme flooding events were estimated for 2050 and 2100, as proposed by the European Directive 2007/60/EC. A set of physical parameters are considered for the multi-attribute analysis based on the Analytic Hierarchy Process, in order to define a Physical Vulnerability Index fundamental to assess coastal vulnerability. For each sea-level rise scenario, coastal vulnerability maps, with a spatial resolution of 20 m, are produced at a national scale to identify areas more vulnerable to sea-level rise, which are key elements for triggering adaptation plans for such vulnerable regions. For 2050 and 2100, it is estimated that there will be 903 and 1146 km2 of vulnerable areas, respectively; the Lisbon district being identified as the most vulnerable in both scenarios. Results are available as a Web Map Service for the Portuguese public entities, and through a web map viewer for the public and communities in general.
Carolina Rocha; Carlos Antunes; Cristina Catita. Coastal Vulnerability Assessment Due to Sea Level Rise: The Case Study of the Atlantic Coast of Mainland Portugal. Water 2020, 12, 360 .
AMA StyleCarolina Rocha, Carlos Antunes, Cristina Catita. Coastal Vulnerability Assessment Due to Sea Level Rise: The Case Study of the Atlantic Coast of Mainland Portugal. Water. 2020; 12 (2):360.
Chicago/Turabian StyleCarolina Rocha; Carlos Antunes; Cristina Catita. 2020. "Coastal Vulnerability Assessment Due to Sea Level Rise: The Case Study of the Atlantic Coast of Mainland Portugal." Water 12, no. 2: 360.
In last decades, Mobile Light Detection And Ranging (LiDAR) systems were revealed to be an efficient and reliable method to collect dense and precise point clouds. The challenge now faced by researchers is the automatic object extraction from those point clouds, such as the curb break lines, which are essential to road rehabilitation projects and autonomous driving. Throughout this work, an efficient method to extract road curb break lines from mobile LiDAR point clouds is presented. The proposed method was based on the system working principles instead of an algorithmic application over the cloud as a mass of points. The point cloud was decomposed in the original sensor scan profiles. Then, a GPS epoch versus trajectory distance was used to eliminate most non-ground points. Finally, through a vertical monotone chain decomposition, candidate point arrays were created and the curb break lines are formed. The proposed method was shown to be able to avoid the occlusion effect caused by undergrowth. The method allows for distinguishing between right and left curbs and works on curved curbs. Both top and bottom tridimensional break lines were extracted. When compared with a reference manual method, in the tested dataset, the proposed method allowed for a decrease in the curb break lines extraction time from 25 min to less than 30 s. The extraction method provided completeness and correctness rates above 95% and 97%, respectively, and a quality value higher than 93%.
Luis Gézero; Carlos Antunes. Automated Road Curb Break Lines Extraction from Mobile LiDAR Point Clouds. ISPRS International Journal of Geo-Information 2019, 8, 476 .
AMA StyleLuis Gézero, Carlos Antunes. Automated Road Curb Break Lines Extraction from Mobile LiDAR Point Clouds. ISPRS International Journal of Geo-Information. 2019; 8 (11):476.
Chicago/Turabian StyleLuis Gézero; Carlos Antunes. 2019. "Automated Road Curb Break Lines Extraction from Mobile LiDAR Point Clouds." ISPRS International Journal of Geo-Information 8, no. 11: 476.
Road rutting caused by vehicle loading in the wheel path is a major form of asphalt pavement distress. Hydroplaning and loss of skid resistance are directly related to high road rutting severity. Periodical measurements of rut depth are crucial to maintenance and rehabilitation planning. In this study, we explored the feasibility of using point clouds gathered by Mobile LiDAR systems to measure the rut depth. These point clouds that are collected along roads are usually used for other purposes, namely asset inventory or topographic survey. Taking advantage of available clouds to identify rutting severity in critical pavement areas can result in considerable economic and time saving and thus, added value, when compared with specific expensive rut measuring systems. Four different strategies of cloud points aggregation are presented to create the cross-section of points. Such strategies were established to improve the precision of individual sensor measurements. Despite the 5 mm precision of the used system, it was possible to estimate rut depth values that were slightly inferior. The rut depth values obtained from each cross-section strategy were compared with the manual field measured values. The cross-sections based on averaged cloud points sensor profile aggregation was revealed to be the most suitable strategy to measure rut depth. Despite the fact that the study was specifically conducted to measure rut depth, the evaluation results show that the methodology can also be useful for other mobile LiDAR point clouds cross-sections applications.
Luis Gézero; Carlos Antunes. Road Rutting Measurement Using Mobile LiDAR Systems Point Cloud. ISPRS International Journal of Geo-Information 2019, 8, 404 .
AMA StyleLuis Gézero, Carlos Antunes. Road Rutting Measurement Using Mobile LiDAR Systems Point Cloud. ISPRS International Journal of Geo-Information. 2019; 8 (9):404.
Chicago/Turabian StyleLuis Gézero; Carlos Antunes. 2019. "Road Rutting Measurement Using Mobile LiDAR Systems Point Cloud." ISPRS International Journal of Geo-Information 8, no. 9: 404.
The railway structures need constant monitoring and maintenance to ensure the train circulation safety. Quality information concerning the infrastructure geometry, namely the three-dimensional linear elements, are crucial for that processes. Along with this work, a method to automated extract three-dimensional linear elements from point clouds collected by terrestrial mobile LiDAR systems along railways is presented. The proposed method takes advantage of the stored cloud point’s attributes as an alternative to complex geometric methods applied over the point’s cloud coordinates. Based on the assumption that the linear elements to extract are roughly parallel to the rail tracks and therefore to the system trajectory, the stored scan angle value was used to restrict the number of cloud points that represents the linear elements. A simple algorithm is then applied to that restricted number of points to get the three-dimensional polylines geometry. The obtained values of completeness, correctness and quality, validate the use of the methodology for linear elements extraction from mobile LiDAR data gathered along railway environments.
Luis Gézero; Carlos Antunes. Automated Three-Dimensional Linear Elements Extraction from Mobile LiDAR Point Clouds in Railway Environments. Infrastructures 2019, 4, 46 .
AMA StyleLuis Gézero, Carlos Antunes. Automated Three-Dimensional Linear Elements Extraction from Mobile LiDAR Point Clouds in Railway Environments. Infrastructures. 2019; 4 (3):46.
Chicago/Turabian StyleLuis Gézero; Carlos Antunes. 2019. "Automated Three-Dimensional Linear Elements Extraction from Mobile LiDAR Point Clouds in Railway Environments." Infrastructures 4, no. 3: 46.
Portugal’s mainland has hundreds of thousands of people living in the Atlantic coastal zone, with numerous high economic value activities and a high number of infrastructures that must be adapted and protected from natural coastal hazards, namely, extreme storms and sea level rise (SLR). In the context of climate change adaptation strategies, a reliable and accurate assessment of the physical vulnerability to SLR is crucial. This study is a contribution to the implementation of flooding standards imposed by the European Directive 2007/60/EC, which requires each member state to assess the risk associated to SLR and floods caused by extreme events. Therefore, coastal hazard on the Atlantic Coast of Portugal’s mainland was evaluated for 2025, 2050, and 2100 over the whole extension due to SLR, with different sea level scenarios for different extreme event return periods. A coastal probabilistic flooding map was produced based on the developed probabilistic cartography methodology using geographic information system (GIS) technology. The Extreme Flood Hazard Index (EFHI) was determined on probabilistic flood bases using five probability intervals of 20% amplitude. For a given SLR scenario, the EFHI is expressed, on the probabilistic flooding maps for an extreme tidal maximum level, by five hazard classes ranging from 1 (Very Low) to 5 (Extreme).
Carlos Antunes; Carolina Rocha; Cristina Catita. Coastal Flood Assessment due to Sea Level Rise and Extreme Storm Events: A Case Study of the Atlantic Coast of Portugal’s Mainland. Geosciences 2019, 9, 239 .
AMA StyleCarlos Antunes, Carolina Rocha, Cristina Catita. Coastal Flood Assessment due to Sea Level Rise and Extreme Storm Events: A Case Study of the Atlantic Coast of Portugal’s Mainland. Geosciences. 2019; 9 (5):239.
Chicago/Turabian StyleCarlos Antunes; Carolina Rocha; Cristina Catita. 2019. "Coastal Flood Assessment due to Sea Level Rise and Extreme Storm Events: A Case Study of the Atlantic Coast of Portugal’s Mainland." Geosciences 9, no. 5: 239.
Based on the updated relative sea level rise rates, 21st-century projections are made for the west coast of Portugal Mainland. The mean sea level from Cascais tide gauge and North Atlantic satellite altimetry data have been analyzed. Through bootstrapping linear regression and polynomial adjustments, mean sea level time series were used to calculate different empirical projections for sea level rise, by estimating the initial velocity and its corresponding acceleration. The results are consistent with an accelerated sea level rise, showing evidence of a faster rise than previous century estimates. Based on different numerical methods of second order polynomial fitting, it is possible to build a set of projection models of relative sea level rise. Applying the same methods to regional sea level anomaly from satellite altimetry, additional projections are also built with good consistency. Both data sets, tide gauge and satellite altimetry data, enabled the development of an ensemble of projection models. The relative sea level rise projections are crucial for national coastal planning and management since extreme sea level scenarios can potentially cause erosion and flooding. Based on absolute vertical velocities obtained by integrating global sea level models, neo-tectonic studies, and permanent Global Positioning System (GPS) station time series, it is possible to transform relative into absolute sea level rise scenarios, and vice-versa, allowing the generation of absolute sea level rise projection curves and its comparison with already established global projections. The sea level rise observed at the Cascais tide gauge has always shown a significant correlation with global sea level rise observations, evidencing relatively low rates of vertical land velocity and residual synoptic regional dynamic effects. An ensemble of sea level projection models for the 21st century is proposed with its corresponding probability density function, both for relative and absolute sea level rise for the west coast of Portugal Mainland. A mean sea level rise of 1.14 m was obtained for the epoch of 2100, with a likely range of 95% of probability between 0.39 m and 1.89 m.
Carlos Antunes. Assessment of Sea Level Rise at West Coast of Portugal Mainland and Its Projection for the 21st Century. Journal of Marine Science and Engineering 2019, 7, 61 .
AMA StyleCarlos Antunes. Assessment of Sea Level Rise at West Coast of Portugal Mainland and Its Projection for the 21st Century. Journal of Marine Science and Engineering. 2019; 7 (3):61.
Chicago/Turabian StyleCarlos Antunes. 2019. "Assessment of Sea Level Rise at West Coast of Portugal Mainland and Its Projection for the 21st Century." Journal of Marine Science and Engineering 7, no. 3: 61.
Data collected at the Cascais tide gauge, located on the west coast of Portugal Mainland, have been analyzed and sea level rise rates have been updated. Based on a bootstrapping linear regression model and on polynomial adjustments, time series are used to calculate different empirical projections for the 21st century sea level rise, by estimating the initial velocity and its corresponding acceleration. The results are consistent to an accelerated sea level rise, showing evidence of a faster rise than previous century estimates. Based on different numerical methods of second order polynomial fitting, it is possible to build a set of projection models of relative sea level rise. Appling the same methods to regional sea level anomaly from satellite altimetry, additional projections are also built with good consistency. Both data sets, tide gauge and satellite altimetry data, enabled the development of an ensemble of projection models. The relative sea level rise projections are crucial for national coastal planning and management since extreme sea level scenarios can potentially cause erosion and flooding. Based on absolute vertical velocities obtained by integrating global sea level models, neo-tectonic studies and permanent Global Positioning System (GPS) station time series, it is possible to transform relative into absolute sea level rise scenarios, and vice-versa, allowing the generation of absolute sea level rise projection curves and its comparison with already established global projections. The sea level rise observed at the Cascais tide gauge has always shown a significant correlation with global sea level rise observations, evidencing relatively low rates of composed vertical land velocity from tectonic and post-glacial isostatic adjustment, and residual synoptic regional dynamic effects rather than a trend. An ensemble of sea level projection models for the 21st century is proposed with its corresponding probability density function, both for relative and absolute sea level rise for the west coast of Portugal Mainland.
Carlos Antunes. Assessment of Sea Level Rise at West Coast of Portugal Mainland and Its Projection for the 21st Century. 2019, 1 .
AMA StyleCarlos Antunes. Assessment of Sea Level Rise at West Coast of Portugal Mainland and Its Projection for the 21st Century. . 2019; ():1.
Chicago/Turabian StyleCarlos Antunes. 2019. "Assessment of Sea Level Rise at West Coast of Portugal Mainland and Its Projection for the 21st Century." , no. : 1.
The georeferenced information acquisition for large scales digital terrain models generation is usually a rather time-consuming and costly process. The use of point clouds gathered by mobile LiDAR systems therefore appears as a possible source for the creation of those models, particularly in remote areas where security issues requires a maximum speed field collection information. However, the filtering challenge to separate the points that represents the terrain surface from the remaining, in an automatic and consistent way, is an open challenge that continues to arouse the interest of researchers. Using a multigrid filtering method, this work presents a comparative analysis of different shapes of regular grid cells, including the implementation algorithms for each cell shape. Also, a coordinate grid concept applied to each cell shape is proposed. Finally, a discussion about the obtained results of the method application using point clouds collected in different environments from different ground LiDAR systems are presented.
L. Gézero; C. Antunes. MULTIGRID CELL SHAPE EVALUATION IN DTM FILTERING OF MOBILE LIDAR POINT CLOUDS. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences 2018, XLII-4, 225 -232.
AMA StyleL. Gézero, C. Antunes. MULTIGRID CELL SHAPE EVALUATION IN DTM FILTERING OF MOBILE LIDAR POINT CLOUDS. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. 2018; XLII-4 ():225-232.
Chicago/Turabian StyleL. Gézero; C. Antunes. 2018. "MULTIGRID CELL SHAPE EVALUATION IN DTM FILTERING OF MOBILE LIDAR POINT CLOUDS." The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4, no. : 225-232.
The digital terrain models (DTM) assume an essential role in all types of road maintenance, water supply and sanitation projects. The demand of such information is more significant in developing countries, where the lack of infrastructures is higher. In recent years, the use of Mobile LiDAR Systems (MLS) proved to be a very efficient technique in the acquisition of precise and dense point clouds. These point clouds can be a solution to obtain the data for the production of DTM in remote areas, due mainly to the safety, precision, speed of acquisition and the detail of the information gathered. However, the point clouds filtering and algorithms to separate “terrain points” from “no terrain points”, quickly and consistently, remain a challenge that has caught the interest of researchers. This work presents a method to create the DTM from point clouds collected by MLS. The method is based in two interactive steps. The first step of the process allows reducing the cloud point to a set of points that represent the terrain’s shape, being the distance between points inversely proportional to the terrain variation. The second step is based on the Delaunay triangulation of the points resulting from the first step. The achieved results encourage a wider use of this technology as a solution for large scale DTM production in remote areas.
L. Gézero; C. Antunes. AN EFFICIENT METHOD TO CREATE DIGITAL TERRAIN MODELS FROM POINT CLOUDS COLLECTED BY MOBILE LiDAR SYSTEMS. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences 2017, XLII-1/W1, 289 -296.
AMA StyleL. Gézero, C. Antunes. AN EFFICIENT METHOD TO CREATE DIGITAL TERRAIN MODELS FROM POINT CLOUDS COLLECTED BY MOBILE LiDAR SYSTEMS. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. 2017; XLII-1/W1 ():289-296.
Chicago/Turabian StyleL. Gézero; C. Antunes. 2017. "AN EFFICIENT METHOD TO CREATE DIGITAL TERRAIN MODELS FROM POINT CLOUDS COLLECTED BY MOBILE LiDAR SYSTEMS." The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-1/W1, no. : 289-296.
In the last few years, LiDAR sensors installed in terrestrial vehicles have been revealed as an efficient method to collect very dense 3D georeferenced information. The possibility of creating very dense point clouds representing the surface surrounding the sensor, at a given moment, in a very fast, detailed and easy way, shows the potential of this technology to be used for cartography and digital terrain models production in large scale. However, there are still some limitations associated with the use of this technology. When several acquisitions of the same area with the same device, are made, differences between the clouds can be observed. The range of that differences can go from few centimetres to some several tens of centimetres, mainly in urban and high vegetation areas where the occultation of the GNSS system introduces a degradation of the georeferenced trajectory. Along this article a different method point cloud registration is proposed. In addition to the efficiency and speed of execution, the main advantages of the method are related to the fact that the adjustment is continuously made over the trajectory, based on the GPS time. The process is fully automatic and only information recorded in the standard LAS files is used, without the need for any auxiliary information, in particular regarding the trajectory.
L. Gézero; C. Antunes. A REGISTRATION METHOD OF POINT CLOUDS COLLECTED BY MOBILE LIDAR USING SOLELY STANDARD LAS FILES INFORMATION. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences 2017, XLII-1/W1, 121 -128.
AMA StyleL. Gézero, C. Antunes. A REGISTRATION METHOD OF POINT CLOUDS COLLECTED BY MOBILE LIDAR USING SOLELY STANDARD LAS FILES INFORMATION. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. 2017; XLII-1/W1 ():121-128.
Chicago/Turabian StyleL. Gézero; C. Antunes. 2017. "A REGISTRATION METHOD OF POINT CLOUDS COLLECTED BY MOBILE LIDAR USING SOLELY STANDARD LAS FILES INFORMATION." The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-1/W1, no. : 121-128.
We propose a 3-D gravity model for the volcanic structure of the island of Maio (Cape Verde archipelago) with the objective of solving some open questions concerning the geometry and depth of the intrusive Central Igneous Complex. A gravity survey was made covering almost the entire surface of the island. The gravity data was inverted through a non-linear 3-D approach which provided a model constructed in a random growth process. The residual Bouguer gravity field shows a single positive anomaly presenting an elliptic shape with a NW–SE trending long axis. This Bouguer gravity anomaly is slightly off-centred with the island but its outline is concordant with the surface exposure of the Central Igneous Complex. The gravimetric modelling shows a high-density volume whose centre of mass is about 4500 m deep. With increasing depth, and despite the restricted gravimetric resolution, the horizontal sections of the model suggest the presence of two distinct bodies, whose relative position accounts for the elongated shape of the high positive Bouguer gravity anomaly. These bodies are interpreted as magma chambers whose coeval volcanic counterparts are no longer preserved. The orientation defined by the two bodies is similar to that of other structures known in the southern group of the Cape Verde islands, thus suggesting a possible structural control constraining the location of the plutonic intrusions.
Patrícia Represas; João Catalão; Fuensanta G. Montesinos; José Madeira; João Mata; Carlos Antunes; Mário Moreira. Constraints on the structure of Maio Island (Cape Verde) by a three-dimensional gravity model: imaging partially exhumed magma chambers. Geophysical Journal International 2012, 190, 931 -940.
AMA StylePatrícia Represas, João Catalão, Fuensanta G. Montesinos, José Madeira, João Mata, Carlos Antunes, Mário Moreira. Constraints on the structure of Maio Island (Cape Verde) by a three-dimensional gravity model: imaging partially exhumed magma chambers. Geophysical Journal International. 2012; 190 (2):931-940.
Chicago/Turabian StylePatrícia Represas; João Catalão; Fuensanta G. Montesinos; José Madeira; João Mata; Carlos Antunes; Mário Moreira. 2012. "Constraints on the structure of Maio Island (Cape Verde) by a three-dimensional gravity model: imaging partially exhumed magma chambers." Geophysical Journal International 190, no. 2: 931-940.
In this study, we present 10 m resolution tsunami flooding maps for Lisbon downtown and the Tagus estuary. To compute these maps we use the present bathymetry and topographic maps and a reasonable estimate for the maximum credible tsunami scenario. Tsunami modeling was made with a non-linear shallow water model using four levels of nested grids. The tsunami flood is discussed in terms of flow depth, run-up height and maximum inundation area. The results show that, even today, in spite of the significant morphologic changes in the city river front after the 1755 earthquake, a similar event would cause tsunami flow depths larger than one meter in a large area along the Tagus estuary and Lisbon downtown. Other areas along the estuary with a high population density would also be strongly affected. The impact of the tide on the extent of tsunami inundation is discussed, due to the large amplitude range of the tide in Lisbon, and compared with the historical descriptions of the 1755 event. The results presented here can be used to identify the potential tsunami inundation areas in Lisbon; this identification comprises a key element of the Portuguese tsunami emergency management system.
Maria Baptista; Jorge Miguel Miranda; Rachid Omira; Carlos Antunes. Potential inundation of Lisbon downtown by a 1755-like tsunami. Natural Hazards and Earth System Sciences 2011, 11, 3319 -3326.
AMA StyleMaria Baptista, Jorge Miguel Miranda, Rachid Omira, Carlos Antunes. Potential inundation of Lisbon downtown by a 1755-like tsunami. Natural Hazards and Earth System Sciences. 2011; 11 (12):3319-3326.
Chicago/Turabian StyleMaria Baptista; Jorge Miguel Miranda; Rachid Omira; Carlos Antunes. 2011. "Potential inundation of Lisbon downtown by a 1755-like tsunami." Natural Hazards and Earth System Sciences 11, no. 12: 3319-3326.
We assessed the performance of a transfer function model for sea-level studies using salt-marsh foraminifera from two estuaries of northern Portugal. An independent data set of 12 samples and 13 sub-fossil samples from a core were used to evaluate if reconstructions and errors derived from current models are adequate. Initial transfer function models provided very strong results as indicated by cross-validation (component 2; r2 = 0.80–0.82; RMSEP ranged from 10.7 to 12.3 cm) and improved its performance by ca. 10% when sample size reached ca. 50. Results derived using an independent test data set indicate that cross-validation is a very effective approach and produces conservative errors when compared to observed errors. We additionally explored the possible effect of transforming the concentration data into percent in the error estimations by comparing the results obtained based on the use of both concentration and compositional data. Results indicate that this type of transformation does not affect the performance of the transfer function. Results derived from a reconstruction of sub-fossil samples from a core indicate that high-resolution sea-level reconstructions are possible, but show that depositional environments have to be selected carefully in order to minimize the impact of possible taphonomical loss.
Eduardo Leorri; Francisco Fatela; Alejandro Cearreta; João Moreno; Carlos Antunes; Teresa Drago. Assessing the performance of a foraminifera-based transfer function to estimate sea-level changes in northern Portugal. Quaternary Research 2011, 75, 278 -287.
AMA StyleEduardo Leorri, Francisco Fatela, Alejandro Cearreta, João Moreno, Carlos Antunes, Teresa Drago. Assessing the performance of a foraminifera-based transfer function to estimate sea-level changes in northern Portugal. Quaternary Research. 2011; 75 (1):278-287.
Chicago/Turabian StyleEduardo Leorri; Francisco Fatela; Alejandro Cearreta; João Moreno; Carlos Antunes; Teresa Drago. 2011. "Assessing the performance of a foraminifera-based transfer function to estimate sea-level changes in northern Portugal." Quaternary Research 75, no. 1: 278-287.
Hydrodynamics and water renewal of intermittent coastal streams are highly variable, at various time scales, due to the very active morphodynamic behavior of their inlets. Due to this strong dynamics, the pathways of water-borne materials — and the consequences of contaminated discharges — can depend strongly on the morphology and environmental conditions. Predicting the fate of contaminants in these systems requires coupled numerical models accounting for the major physical and water quality processes. We aim at improving the understanding of the impact of inlet morphology and wave action on the pollutant and sediment pathways of these small coastal systems, based on a suite of calibrated and validated coupled models. Two analyses, based on particle simulations, are presented to assess sediment dynamics and pollutant pathways for several conditions. Results show that waves have a major effect on the fate of water-borne materials in the estuary. Wave-induced currents sweep away materials coming out of the estuary, while wave-induced setup has a profound effect on tidal propagation, water levels and velocities in the estuary, promoting the upstream transport of pollutants.
Anabela Oliveira; André B. Fortunato; Martha Guerreiro; Xavier Bertin; Nicolas Bruneau; Marta Rodrigues; Rui Taborda; César Andrade; Ana Maria Silva; Carlos Antunes; Paula Freire; L. Simões Pedro; Guillaume Dodet; Carlos Loureiro; Ana Mendes. Effect of Inlet Morphology and Wave Action on Pollutant Pathways and Sediment Dynamics in a Coastal Stream. Estuarine and Coastal Modeling (2009) 2010, 601 -620.
AMA StyleAnabela Oliveira, André B. Fortunato, Martha Guerreiro, Xavier Bertin, Nicolas Bruneau, Marta Rodrigues, Rui Taborda, César Andrade, Ana Maria Silva, Carlos Antunes, Paula Freire, L. Simões Pedro, Guillaume Dodet, Carlos Loureiro, Ana Mendes. Effect of Inlet Morphology and Wave Action on Pollutant Pathways and Sediment Dynamics in a Coastal Stream. Estuarine and Coastal Modeling (2009). 2010; ():601-620.
Chicago/Turabian StyleAnabela Oliveira; André B. Fortunato; Martha Guerreiro; Xavier Bertin; Nicolas Bruneau; Marta Rodrigues; Rui Taborda; César Andrade; Ana Maria Silva; Carlos Antunes; Paula Freire; L. Simões Pedro; Guillaume Dodet; Carlos Loureiro; Ana Mendes. 2010. "Effect of Inlet Morphology and Wave Action on Pollutant Pathways and Sediment Dynamics in a Coastal Stream." Estuarine and Coastal Modeling (2009) , no. : 601-620.
Foraminiferal living assemblages from a brackish tidal marsh were studied across three sampling transects, under Spring and Autumn conditions. Foraminiferal analysis was also extended to the dead assemblages of Spring samples. Altimetric control of each sampling point was acquired through the connection to the national datum by GPS differential positioning combined with a regional geoid model. The influence of the geochemical characteristics on the assemblages including chemical composition of the estuarine and marsh surface sediments, in addition to salinity, pH and calcite saturation of estuarine and marsh interstitial waters was evaluated. A high affinity was found between Spring and Autumn living assemblages, probably related to the low number of representative species. The affinity also found between living and dead assemblage was seen as a consequence of low pH and calcite undersaturation that prevent the accumulation effect of several generations of foraminifera. Salinity appears as a clear constraint to the foraminiferal assemblages composition that is enhanced by calcite undersaturation in brackish marshes interstitial waters and sediments. Generally abundant marsh species like Trochammina inflata, Jadammina macrescens and the calcareous foraminifera are limited to an episodic presence. Foraminiferal assemblages distribution across brackish tidal marsh can be assumed as an elevation proxy. The high marsh IB sub-zone is dominated by Haplophragmoides sp. and Haplophragmoides manilaensis. Low marsh zone II is characterised by the dominance of Miliammina fusca but can be subdivided in an IIA upper part, where is followed by Pseudothurammina limnetis, and in a IIB lower part defined by a subsidiary presence of Psammosphaera sp. Haplophragmoides manilaensis dominance between 1.55 m and 1.67 m, at living as well as dead assemblages, suggests this species as a potential sea-level indicator for the brackish tidal marshes.
Francisco Fatela; João Moreno; Filipa Moreno; M. Fatima Araujo; Teresa Valente; Carlos Antunes; Rui Taborda; Cesar Andrade; Teresa Drago. Environmental constraints of foraminiferal assemblages distribution across a brackish tidal marsh (Caminha, NW Portugal). Marine Micropaleontology 2009, 70, 70 -88.
AMA StyleFrancisco Fatela, João Moreno, Filipa Moreno, M. Fatima Araujo, Teresa Valente, Carlos Antunes, Rui Taborda, Cesar Andrade, Teresa Drago. Environmental constraints of foraminiferal assemblages distribution across a brackish tidal marsh (Caminha, NW Portugal). Marine Micropaleontology. 2009; 70 (1-2):70-88.
Chicago/Turabian StyleFrancisco Fatela; João Moreno; Filipa Moreno; M. Fatima Araujo; Teresa Valente; Carlos Antunes; Rui Taborda; Cesar Andrade; Teresa Drago. 2009. "Environmental constraints of foraminiferal assemblages distribution across a brackish tidal marsh (Caminha, NW Portugal)." Marine Micropaleontology 70, no. 1-2: 70-88.
The determination of the local gravity field by means of the point mass inversion method can be performed as an alternative to conventional numerical methods, such as the least-squares collocation. Based on the first derivative of the inverse-distance Newtonian potential for the representation of the gravity anomaly data, it is possible to compute any wavelength component of the geoid in planar approximation with sufficient accuracy. In order to exemplify the theoretical concept, two applications are presented of the computation of two different wavelength components of the geoid, the long wavelength component in a local solution and the short wavelength component in a regional solution. The results are compared with corresponding least-squares collocation solutions, using a global geopotential model to remove and to restore the long wavelength component.
Carlos Antunes; R. Pail; João Catalão. Point Mass Method Applied to the Regional Gravimetric Determination of the Geoid. Studia Geophysica et Geodaetica 2003, 47, 495 -509.
AMA StyleCarlos Antunes, R. Pail, João Catalão. Point Mass Method Applied to the Regional Gravimetric Determination of the Geoid. Studia Geophysica et Geodaetica. 2003; 47 (3):495-509.
Chicago/Turabian StyleCarlos Antunes; R. Pail; João Catalão. 2003. "Point Mass Method Applied to the Regional Gravimetric Determination of the Geoid." Studia Geophysica et Geodaetica 47, no. 3: 495-509.
Despite their relative poor precision, classical geodetic observations can provide valuable information about tectonic displacements because their lack of precision is balanced by the time span they cover. In the case of the Açores archipelago the contribution of six decades of classical observations provide a historically reliable and important source of information in the establishment of a tectonic model for that area, complementary to GPS data, where only few years of observations are available. Based upon angular and invar wire measurements carried out in the thirties, compared with more recent classical and GPS observations, the authors were able to deduce some significant displacements. For the Central Group, we conclude that the area is expanding in an approximately WSW–ENE direction, showing a component parallel to the plate boundary between Eurasia and Africa, which is about 1.5 greater than the component in the perpendicular direction. As regards the Faial and S. Jorge islands, our results show a good agreement with the proposed geodynamic models for Faial, but not for S. Jorge. For Faial, the results indicate an extension perpendicular to the faults in the direction WNW–ESE, and a dextral strike slip along the same faults. In the case of S. Jorge the lack of agreement with the proposed geodynamic models is probably due to the particular poor geometry and scale control of the inner network.
J Pagarete; J Teixeira Pinto; Virgilio Mendes; Carlos Antunes; H Ribeiro. The importance of classical geodetic observations for analyzing the geodynamic behaviour of the Açores archipelago. Tectonophysics 1998, 294, 281 -290.
AMA StyleJ Pagarete, J Teixeira Pinto, Virgilio Mendes, Carlos Antunes, H Ribeiro. The importance of classical geodetic observations for analyzing the geodynamic behaviour of the Açores archipelago. Tectonophysics. 1998; 294 (3-4):281-290.
Chicago/Turabian StyleJ Pagarete; J Teixeira Pinto; Virgilio Mendes; Carlos Antunes; H Ribeiro. 1998. "The importance of classical geodetic observations for analyzing the geodynamic behaviour of the Açores archipelago." Tectonophysics 294, no. 3-4: 281-290.