Papers
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On the Organic Micro-Pollutants and Heavy Metals in the Pearl River Estuary
N/A
Year: 2001
Number Pages:
165-178.
Author(s): Cardoso da Silva, M.; Dai, M.; Hong, H.; Wang, X.; Martin, J. M; Trincherini, P.; Huang, B.; Zang, Z.
Editor: In Gawlik, B. M., B. Platzer e H. Muntau (Eds.) - Freshwater contamination in China. Current Topics of Research (EUR 19770),
Volume:
European Commission, Office for the Official Publications of the European Communities.
Info
Oscillation-removal schemes for salinity studies
Three alternative methods to remove oscillations in two-dimensional Eulerian-Lagrangian salt transport simulations are compared: a Flux-Corrected Transport (FCT) scheme, a non-linear filter (NLF) and the explicit introduction of diffusion. The three formulations are implemented in a high-accuracy Eulerian-Lagrangian model (ELM), and are applied to the salinity propagation in the Guadiana estuary (Portugal). This test allows both for a stringent comparison in a real setting where adequate field data is available, and to assess the practical consequences of the choice of the numerical scheme. The evaluation of the schemes confirms a previous analysis showing that the FCT-based method provides the best results, closely followed by the non-linear filter. For these methods, oscillations are removed with minimal numerical damping, and the agreement with field data is good. The performance of the base model with non-zero diffusion coefficients is case-dependent, improving its results as the mixing of the front increases due to larger river flows. For the Guadiana estuary, the choice of the numerical scheme is crucial: important indicators, such as the domain-integrated residence time and the limit of salinity intrusion, may have errors up to 25%, if an artificially diffusive method is used to avoid numerical oscillations.
Year: 2001
Number Pages:
501-518.
Author(s): Oliveira, A.; Fortunato, A. B.
Editor: Estuarine and Coastal Modeling 7
Volume:
ASCE.
Info
Para uma melhor gestão dos serviços de água
N/A
Year: 2001
Number Pages:
20-21.
Author(s): Alegre, H.
Editor: Revista Ambiente 21-Sociedade e desenvolvimento, secção Inovação científica e técnica . Nº 0, ano 1 e Nº 1, ano 1
Info
Sea water intrusion vulnerability mapping of aquifers using the GALDIT method
N/A
Year: 2001
Number Pages:
12 pp.
Author(s): Chachadi, A. G.; Lobo Ferreira, J. P. C.
Editor: Coastin e Modelling in Hydrogeology
Volume:
Number 4.
Info
Seismic hazard for the Central Group of the Azores Islands
Probabilistic seismic hazards maps have been prepared either for the archipelago of the Azores in general terms, or for the islands of the Central Group using updated seismic information for the region, including a revision of the earthquake catalogue for the period 1522-1998. Two different approaches were used: (i) a standard seismic source model and (ii) a semi-zonified source model based on spatially smoothed seismicity where no delineation of seismic sources is needed. Preliminary data point out that high PGA values were obtained for an area located to the west of the Central Group and for an area between Terceira and the São Miguel Islands. Deaggregation of hazard for some counties was evaluated and results are presented in terms of mean and modal values of magnitude and distance, showing that the main contributions to hazard in all counties are from close-in and not very severe earthquakes.
Year: 2001
Number Pages:
89-105pp.
Author(s): Carvalho, A. M.; Luísa Sousa, M.; Oliveira, C.S.; Nunes, J. C.; Campos Costa, A.; Forjaz, V.H.
: Bollettino di Geofisica Teorica ed Applicata
Editor: OGS
Volume:
Vol. 42, Nº 1-2.
Keywords: Azores; Probabilistic seismic hazards
Info
A sea wave study at the entrance of the Tagus estuary
N/A
Year: 2000
Number Pages:
19 p.
Author(s): Fortes, C. J. E. M.; Capitão, R.; Oliveira, F. S.; Covas, J. A.; Vaz dos Santos, M. A.; Sancho, F. E.
Editor: Revista Thalassas, International Journal of Marine Sciences. Vigo, Espanha, Novembro de 2000
Info
A Tidal Model of the Iberian Atlantic Shelf: First Results
Barotropic tides in the Iberian Atlantic shelf were simulated using a finite element model. The model was validated with data from twelve coastal gauges. The model reproduces the known behavior of semi-diurnal tides, which propagate northward as Kelvin waves, and predicts the existence of amphidromes in the Strait of Gibraltar for the diurnal waves. Model results were then used to specify boundary conditions for a tidal model of the Guadiana estuary. Results show that the spatial variability of tidal boundary conditions in estuarine models can be necessary for the accurate representation of the mixing between estuarine and ocean waters.
Year: 2000
Number Pages:
41-47.
Author(s): Fortunato, A. B.; Ferreira, J. S.; Oliveira, A.
Editor: Thalassas
Volume:
16.
Info
Aquifer recharge and evaluation of groundwater vulnerability to pollution
N/A
Year: 2000
Number Pages:
8-9 pp.
Author(s): Lobo Ferreira, J. P. C.
Editor: Coastin
Volume:
Number 2.
Info
Contribuição da tomografia sísmica na caracterização do maciço da zona da central de Venda Nova II
Na actual configuração do reforço de potência de Venda Nova II, a implantação da caverna da centralsitua-se no maciço granítico da Borralha a uma profundidade de 350 metros. A partir da superfícieforam executadas 4 sondagens verticais, profundas, com recuperação contínua de amostra. Entre essesfuros foram seguidamente realizados leques sísmicos para obtenção de tomografias sísmicas develocidade das ondas longitudinais em várias secções entre furos. As tomografias sísmicascontribuíram, em conjunto com a geologia de superfície e os resultados da prospecção mecânica, paraa definição do modelo geológico-geotécnico do maciço rochoso e para a localização da caverna dacentral.
Year: 2000
Number Pages:
6pp.
Author(s): Coelho, M. J.
Editor: SPG
Info
Improvement on open boundaries on a time dependent numerical model of wave propagation in the nearshore region
An improvement on the simulation of outgoing waves on a time dependent numerical model for water wave propagation in the nearshore region is presented. The governing equations consist of a system of first order partial differential equations (PDEs), the equation of continuity and the equation of motion. A comparative study of first order radiation boundary conditions (BCs) and first order radiation BCs combined with sponge layers is presented for cases where outgoing waves leave the numerical domain of calculation through the open boundary. A reduction of spurious reflections from the numerical open boundaries can be obtained with an irrelevant increase in terms of computational cost.
Year: 2000
Number Pages:
95-115.
Author(s): Oliveira, F. S. B. F.
Editor: Ocean Engineering
Volume:
28.
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