A. Santos

Technical University of Lisbon | UTL · Centre for the Environment and Maritime Technologies (MARETEC)

Over the last decade, the Antarctic continent has been the object of intensive scientific programmes. However, the emphasis of these studies rarely focuses on the Antarctic as a source of potential elements such as mercury. The release of mercury to the environment is known to occur at Deception Island, associated with volcanic activity. In this st...

Fluids mixing in microfluidics is hindered by the laminar flow regime operation and, therefore, it constitutes an important challenge. Symmetrical and asymmetrical T-micromixers are used to assess the mixing quality improvement, when pulsed signals are imposed to the inlet flows. The used chips are manufactured using polydimethylsiloxane and soft l...

The applicability of a numerical model following a downscaling methodology was evaluated for the southeastern Brazilian shelf (regional model) and Paranaguá estuarine system (local model). This approach permits the simulation of different scale processes, such as storm surges and coastal upwelling, and is suitable for operational forecasting purpos...

During summer (June, July, and August), northerly winds driven by the Azores anticyclone are prevalent over western Iberia. The Quick Scatterometer Satellite 2000 to 2009 summertime estimates reveal a broad high wind speed (≥7 ms À1) area extending about 300 km from shore and along the entire Iberian west coast. Nested in this large high-speed regi...

This work presents the setting and validation of a numerical model for the southeastern Brazilian shelf (regional model) and Paranaguá estuarine system (local model) through a downscaling approach. The model results were validated with tidal gauges data, Argo floats profiles and Sea Surface Temperature (SST) from satellite measurements. The regiona...

The aim of this work is to analyze the importance of the relationship between sealevel and bottom pressure variability on the satellite altimetry assimilation with Cooper and Haines (CH) method [1] in a primitive equations regional ocean model. The CH method assumes that potential vorticity must be conserved when satellite altimetry is assimilated,...

Previous research shows that storm surge episodes occur frequently at the mouth of the Tagus Estuary, causing important water level anomalies in Lisbon and Cascais tide gauge records and having important effects in coastal erosion. Atmospheric pressure is indicated as the main driver of storm surge events in the West Iberian Peninsula. However, the...

This article presents a methodology for simulating the Algarve coastal circulation using realistic forcing (e.g. low-frequency circulation, tide, high-resolution atmospheric forcing). Low-frequency open boundary conditions are defined via a downscaling of the HYCOM-US operational solution for the Gulf of Cadiz. Atmospheric forcing is imposed using...

A bio-physical model of sardine larvae off the Atlantic Portuguese coast, incorporating a three-dimensional circulation model, was used to estimate changing biomass during winter upwelling and downwelling events. The growth rate of larvae was modelled as a function of age, temperature, and prey concentration and the mortality rate as a function of...

This paper presents a new numerical model for the study of circulation in coastal and deep ocean regions. Sigma coordinate models are appropriate where currents follow topography, but there are problems of numerical diffusion in stratified areas. Some of these problems can be partly overcome by applying instead a cartesian model, whose outcome, how...

We used a three-dimensional model with generic vertical coordinate to investigate the structure of flow and transports on the Iberian shelf-slope region. Two different types of experiments were conducted. The first was a process-oriented study to investigate the role of thermohaline forcing in the generation and meridional variability of the polewa...

This work compares the numerical results of a three-dimensional hydrodynamic baroclinic model and a known analytical solution due to Baines of the baroclinic lunar semidiurnal (M2) tidal propagation over the continental shelf. The simplifying numerical approaches are the Boussinesq and the hydrostatic hypothesis. The hydrostatic pressure restricts...

Abstract Mathematical modeling, although a recent science, can be considered old when the time scale used to measure ,its age is the information technology evolution. FORTRAN 77 ,has ,been ,the most ,popular ,programming ,language ,among hydrodynamic,modelers over the last two decades. This language was,adequate to the (low) complexity of the model...

A main concern in three-dimensional coastal and oceanic modelling is the type of coordinate used for the vertical direction. The appropriate coordinate system should guarantee an adequate resolution in the entire domain and must lead to a stable method with minimal numerical diffusion in order to preserve the vertical structure of the water column....

The present paper studies circulation in the Ria of Vigo (northwest Spain) by means of a 3-D baroclinic model coupled with a Lagrangian model of dispersion. The model is examined to ob-tain the residual currents' underlying periodic tidal movements. These currents are related to the quality of water because they determine the residence time. The mo...

A three-dimensional hydrodynamic model is used to investigate the poleward flow along the western European slopes. The area of the model domain goes from northwest Africa to Ireland. During a first stage, the currents are driven by climatological density fields. In a second stage the model is also forced by climatological winds, although special at...

A 3D baroclinic model has been applied to study residual circulation in the Rı́a of Vigo (NW Spain) under different seasonal conditions. Winter, spring and non-upwelling summer conditions have been simulated. The use of a D model allows the spatial structure of residual circulation to be studied, both horizontaly and verticaly, and the combined eff...

Circulation in the Atlantic Iberian continental margin is markedly seasonal being dominated by a southward surface current driven by the wind during the upwelling season and by a poleward density driven current during the winter. The poleward current extends from about the depth of Mediterranean Water to 200 m during the upwelling season and reache...

In this work several radiation boundary conditions applied in ocean barotropic models are studied and a forced wave radiation condition is proposed for wind and/or tide driven flows. Tests performed include tide and wind forcing and the results were compared with model results from expanded domains in terms of kinetic energy, potential energy, mean...