Paulo Leitão

• PhD
• Researcher at Hidromod

Safe navigation in inland waters subjected to tide requires dedicated forecasts of meteorological and oceanographic variables, such as local tidal height, currents, wind and atmospheric pressure. Indeed, it is more difficult to navigate inland shallow waters subjected to intense morphologic dynamics, and therefore characterized by the non-linearity...

Forecasting estuarine circulation is a hot topic, especially in densely populated regions, like Santos (Brazil). This paper aims to improve a water-level forecasting system for the Santos estuary, particularly the physical forcing determining the residual tide, which in extreme cases increase the predicting errors. The MOHID hydrodynamic model was...

An integrated hydrodynamic and Lagrangian transport model was used to estimate the average residence time in the Bahia Blanca estuary (Argentina) for wind conditions of different seasons. The Bahia Blanca estuary consists on an elongated system of meandering bays surrounded by tidal flats and salt marshes where the tide is the principal forcing. Mo...

Historically, extratropical cyclones associated with frontal systems cause storm surges in Santos city. Although there are no fatality records, these events cause several socio-economic loss, especially in vulnerable regions including the Port of Santos. Accepting the impossibility of eliminating the risks, adapting to natural phenomenon can be acc...

The South China Sea region, and particularly the Malacca and Singapore Straits, are known by the complex tidal dynamics, which is influenced by the tidal propagation from Pacific and Indian Oceans. In spite of the dynamic complexity, the region is very relevant economically, especially concerning the growing oil drilling activities. To give support...

Em diversas regiões costeiras tem-se buscado a minimização dos riscos à saúde humana associados as más condições de balneabilidade das praias, nesse sentido os modelos preditivos são uma ferramenta importante para gestão balnear. Nesta comunicação é apresentado um sistema de previsão da qualidade das águas nas praias de uma importante região costei...

Coastal defence structures are often constructed to prevent beach erosion. However, poorly designed structures may cause serious erosion problems in the downdrift direction. Morphological models are useful tools to predict such impacts and assess the efficiency of defence structures for different scenarios. Nevertheless, morphological modelling is...

There is a close relationship between productivity of farmed salmon and sea temperature. This report is focused on bottom water temperature variability, offshore mainland Portugal, to support initial decisions on the viability of salmon farming in Portugal. Input data is mainly from CMEMS (Copernicus Marine Environment Monitoring Service). For the...

The complexity of sediment dynamics in aquatic systems can be better understood by applying numerical models. The development of a comprehensive morphological model is presented in this paper. The model aims to predict the sediment transport and bed evolution in natural systems composed of different sediment types. The morphological model was imple...

Coastal defence structures are often constructed to prevent beach erosion. However, poorly designed structures may cause serious erosion problems in the downdrift direction. Morphological models are useful tools to predict such impacts and assess the efficiency of defence structures for different scenarios. Nevertheless, morphological modelling is...

There is a steady increase in cargo handled in ports, there is a tendency of increase in the ships size seeking to optimize logistics, as evidenced by recent data for Porto of Santos operations. Once the adjustment of port infrastructure occurs more slowly, it may increase the risk of navigation in shallow waters and narrow port channels, especiall...

Operational weather forecast systems, based on the AQUASAFE platform, have been set up for several ports in Europe and South America, to support the need to increase productivity and maintain safety. This platform can be used to downscale waves and currents' forecasts to a resolution of the order of 10 to 100 m and disseminate modelled and measured...

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...

Recent studies suggest the propagation and run-up of tsunamis can be strongly influenced by dispersion due to non-hydrostatic effects, which can result in up to 60% higher values of coastal run-up than the ones calculated by hydrostatic models. In this communication the validation of a non-hydrostatic version of MOHID model is presented. This versi...

RESUMO Diversas instituições estão a disponibilizar, com base na plataforma AQUASAFE, um conjunto de serviços de previsão de alta resolução para diferentes zonas costeiras com especial enfoque nas operações portuárias e na prevenção de eventos de poluição costeira decorrentes de acidentes, descargas de rios, sistemas de drenagem urbana, instalações...

Atualmente a utilização de modelos operacionais que simulam a circulação nos oceanos, regiões costeiras e estuarinas está bastante difundida. Estes sistemas são importantes ferramentas para auxílio na tomada de decisão; no caso dos modelos de pequena escala podemos citar como exemplo a utilização para previsão das condições de navegabilidade em áre...

Ocean circulation models are frequently used in maritime Search and Rescue operations due to their skill in simulating the effects of local currents on the transport of people or objects. They are also occasionally used in forensic contexts. Frequently, positively or neutrally buoyant passive particles are used in these simulations, as a proxy for...

Managing combined sewage systems in large cities discharging to coastal waters, often bearing recreational activities, remains a challenge. Studying the impacts of such discharges requires the development of specific models. Hydrodynamic and water quality modelling of coastal waters employs numerical methods and algorithms, leading to the design of...

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...

In this document the implementation of MOHID in parallel mode to the Rias Baixas area by Hidromod in the framework of the RaiaCO project is described. The work was sub-contracted by MeteoGalicia, one of RaiaCO partners. This MOHID Rias Baixas implementation main objective was to simulate 3 days of 3D circulation for the entire Rias Baixas area...

Implementation of MOHID in parallel mode to the Rias Baixas area by Hidromod in the framework of the RaiaCO project is described. The work was sub-contracted by MeteoGalicia, one of RaiaCO partners. This MOHID Rias Baixas implementation main objective was to simulate 3 days of 3D circulation for the entire Rias Baixas area with a spatial resolution...

The simulated droplet trajectories of the 3-D model at the Caribbean platform showed that droplets with a diameter of 50μmformed a distinct subsurface plume, which was transported horizontally and could remain below the surface. This plume could have a very restricted area of impact because the dispersion is only controlled by the ocean currents wh...

This work studies the influence of the Tagus estuary, Portugal, on the near coastal system using a model application to describe the main physical and biogeochemical processes in the Region of Freshwater Influence (ROFI). It was used a nested modeling approach, downscaling the solution for the general circulation from a larger domain model (the Por...

The Bahía Blanca estuary is a complex system of channels and tidal flats where the most important deep water harbour system of Argentina is located. The main goal of the present work was to obtain a hydrodynamic conceptual model for the Bahía Blanca coastal area. For this reason, a combined analysis of observed data and numerical modelling has been...

In this document the MOHID parallelization upgrade done by Hidromod in the framework of the EnergyMare project is described. The work was sub-contracted by MeteoGalicia, one of EnergyMare partners. This upgrade had a global objective of increasing the speedup factor associated with MOHID modelling system's parallelization. A specific goal was t...

O aumento constante dos volumes de mercadorias movimentados nos Portos, do tamanho dos navios e a da importância da cadeia logística, conduzem à necessidade de ter previsões meteo-oceanográficas cada vez melhores e mais integradas na operação portuária. Sendo a adaptação das infraestruturas portuárias um processo mais lento que o do aumento dos nav...

Background An alternative initialization method to [1] was developed to reduce the spin up time on regional Ocean Model simulations. The method was applied to the regional model of the circulation in the Bay of Biscay. Two initialization schemes were tested and compared using in situ data (Argo floats and microwave SST); a slow start initialization...

1) HIDROMOD, Rua Rui Teles Palhinha nº 4 1º, 2740-278, Porto Salvo. madalena@hidromod.com (2) IST-Maretec, Av. Rovisco Pais 1, 1049-001 Lisboa Resumo: Neste trabalho foi implementado um sistema de modelação integrado para simular o efeito das cheias no Estuário do Espírito Santo/Baía Maputo (Moçambique). O sistema implementado permite sobrepor à es...

Oceanographers and modelers often relate chlorophyll concentrations with phytoplankton carbon invoking a suitable C:Chla ratio. However C:Chl ratios are not constant in natural systems, thus making chlorophyll a deceptive measure of true biomass.In this paper we report on the adaptation of an algorithm for chlorophyll synthesis to a complex ecologi...

In the framework of the Lenvis project, a web service infrastructure able to provide professional users with field data and model results in real time was developed. One of the web services developed (web service model) executes a particle tracking model to simulate the dispersion of sewage discharges. This web service is comprised of a web client...

Ria Formosa lagoon, located in Algarve, south of Portugal, is a barrier islands system that communicates with the sea trough 6 inlets. Five of these inlets are natural born and have mo- bility characteristics and the 6 th is an artificial inlet that has been opened with the purpose of making it easier to access to the port of Faro. In order to main...

Resumo Nos próximos 5 anos espera-se um aumento na área regado do Sado que poderá atingir 25 000 hectares. Associada a esta alteração a qualidade da água que chega ao estuário do Sado poderá diminuir. Para estimar o impacto das alterações de uso de solo na qualidade da água foi implementado o modelo SWAT à bacia hidrográfica do Sado. O SWAT é um mo...

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The management of coastal systems where overlapping economic interests compete for the same resources make the use of integrated approaches indispensable. The Integrated Coastal Zone Management (ICZM) focuses mainly on three major goals: (1) overcoming the conflicts associated with the sectorial management, (2) preserving the productivity and biolo...

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,...

Plumes of buoyant water produced by inflow from rivers and estuaries are common on the continental shelf. Buoyancy associated with estuarine waters is a key mediating factor in the transport and transformation of dissolved and particulate materials in coastal margins. The offshore displacement of the plume is influenced greatly by the local alongsh...

The use of high resolution hydrodynamic modelling to simulate the potential effects of tsunami events can provide relevant information about the most probable inundation areas. Moreover, the consideration of complementary data such as the type of buildings, location of priority equipment, type of roads, enables mapping of the most vulnerable zones,...

The role of oceanic tide, wind stress, freshwater river inflows, and waves in the long-term circulation and residence time in Óbidos Lagoon is investigated using a sensitivity analysis carried out by means of a two-dimensional model. MOHID modeling system coupled to Steady-State Spectral Wave model for simulate Óbidos Lagoon circulation were implem...

This study reports the role of waves, tide, wind and freshwater discharges over the sea level in Óbidos Lagoon, a coastal system connected to the sea through a narrow and shallow mobile inlet. To address the hydrodynamic features of this coastal system, the relative importance of different physical forcings were evaluated. For this purpose, observa...

A 3D baroclinic model (Mohid) is used to perform hindcast simulations in a tidal channel: the Espinheiro Channel (Portugal). These simulations are conducted for four distinct periods where markedly different river discharge and tides occurred, and the outputs are compared to time series measurements and synoptic thermohaline data. The model reveals...

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...

Aysen fjord is one of the natural connections between the Andean mountains and the system of islands and fjords in southern Chile, called the Chilean Inland Sea. In this fjord, several extreme events take place which make it special from an oceanographic point of view: very large river discharges fed by rain and by melt water from the Andes glacier...

Vaz, N., Fernandes, L., Leitão, P.C., Dias, J.M. and Neves, R., 2009. The Tagus estuarine plume induced by wind and river runoff: Winter 2007 case study. Journal of Coastal Research, SI 56 (Proceedings of the 10th International Coastal Symposium), 1090 - 1094. Lisbon, Portugal, ISBN 0749-0258. Plumes of buoyant water produced by inflow from rivers...

Óbidos Lagoon is a small coastal system connected to the sea through a shallow, narrow and mobile inlet. The lagoon is characterized by large accretion rates and cyclic water quality problems due to large water renewal time scales. Over the years the inlet position often drifted from north-south and south-north. As a consequence, every time the inl...

A 3D baroclinic model (Mohid) was used to perform hindcast simulations in a tidal channel – Espinheiro Channel (located within Ria de Aveiro, north coast of Portugal) – in order to study its hydrography. The simulations were conducted for four distinct periods where markedly different river discharge and tides occurred and the outputs are compared...

In Ria de Aveiro, tides are distorted as they progress from the mouth toward the end of the channels. The general characteristics of the tidal wave are those of a damped progressive wave, presenting a decrease of the tidal amplitude and an increase of the phase lag due to bottom friction. According to the results obtained, Mohid-2D was successfully...

Óbidos lagoon is a small coastal system connected to the sea through a shallow mobile inlet. The lagoon that is the support of an important ecosystem, beyond a natural accretion tendency, common to these coastal lagoons, suffers from cyclic water quality problems related with the difficulties in renewing the water due to the closing of its inlet. B...

An integrated system named METEOMOHID, developed by MeteoGalicia in the first stage of the Prestige accident in November 2002 was used successfully in an operational form to support decision making and assist in recovering tasks. Afterwards, METEOMOHID has been enhanced with the aim of developing an operational oceanography system to be used in the...

This work presents results from two complementary and interconnected approaches to study water temperature and salinity patterns in an estuarine tidal channel. This channel is one of the four main branches of the Ria de Aveiro, a shallow lagoon located in the Northwest coast of the Iberian Peninsula. Longitudinal and cross-sectional fields of water...

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...

This paper describes an application of MOHID modelling system to a shallow temperate coastal lagoon in Portugal's western coast (Ria de Aveiro), simulating more than one primary producer, for a better understanding of the existing ecological dynamics and creating a useful tool to delineate land activities management practices. MOHID water quality m...

With increasing computer power, the modelling tools for water resources, nowadays, not only integrate physical-based transport models with biogeochemical process models, but also couple surface water body models, groundwater models and hydrographic basin models. This paper describes how the MOHID Water Modelling System achieves the mentioned integr...

This paper describes some of the needs and problems associated to the assessment of coastal and estuarine problems (sediment transport and eutrophication). The development of an integrated system including EO data, local measurements with special emphasis on modeling tools, is presented as a solution for studying and helping decision making on the...

The aim of this work is within EUROSTRATAFORM project and consists on developing a model for sedimentary processes and their forcing conditions on the European continental margin (main concern on Nazaré and Setúbal Canyons), constrained by the requirement of considering the continental margin as a continuum and of following the sediments from their...

On November 13th 2002, the tank ship Prestige-Nassau sent a SOS signal. The hull of the ship was damaged producing an oil spill in front of the Galician coast (NW Spain). The damaged ship took north direction spilling more fuel and affecting the western Galician coast. After this, it changed its track to south. At this first stage of the accident,...

From the first stages of the accident of the Prestige-Nassau, an operative system of monitoring and forecasting of the spill was created. To explain the path followed by the oil spill, it was classified in three parts of spills. The first spill takes place from 11/13/2002 until the ship broke in two and corresponds to the slick of fuel when the shi...

In this article, a three-dimensional primitive equation model is applied to Sado Estuary, which is a meso-tidal homogeneous estuary. Despite the homogeneity of its density field, the flow presents important vertical structures. This article shows that the common practice of using two-dimensional depth-integrated models in homogeneous estuaries can...

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...

The Ria de Pontevedra is one of the Galician Rias Baixas, partially mixed estuaries on the north-west coast of the Iberian peninsula. The hydrodynamics of the rias is far from being fully understood. In this application, the hydrodynamics of the Ria de Pontevedra is studied by means of a 3-D baroclinic model. Our aim was to establish the circulatio...

Sado estuary (Portugal) is a mesotidal well-mixed estuary. The flow however, displays strong three-dimensional features associated with bathymetry variations. The flow is simulated using a three-dimensional primitive equation model based on the finite-volume method and incorporating a new concept for the vertical discretization. The innovative feat...

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...

SUMMARY The most popular simulation models (e.g. HYDRUS, MODFLOW, RZWQM, MACRO) were basically disseminated in the nineties. However their development started earlier, when the compute capacity was insignificant when compared with nowadays. For this reason these models were made for specific applications. The water circulation in the soil obeys the...

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....

A two-dimensional hydrodynamic model coupled to a particle tracking model is applied to study the dispersion processes and residence time in two Galician rias (A Coruña and Vigo, NW Spain) under summer conditions. In A Coruña a long residence time was found in the harbour area due to the existence of a dock, and a short one in the river area. On th...

This paper presents the coupling of a biochemical model with two different hydrodynamic models, a 1-D model (Coelho, 1996) and a 3-D model (Santos, 1995), corresponding to two successive work phases. In the first phase the 1-D hydrodynamic model was used to calibrate the biochemical model; the results of this phase made it possible to analyse tempo...

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 three-dimensional primitive equation model and its application to a tidal estuary is described. The model ,solves the primitive equations for incompressible ,fluids with Boussinesq and hydrostatic approximations. The discretization is based ,on the ,finite volume ,method and allows a general vertical coordinate. The computational,code is implemen...

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...

A three-level nested, pre-operational model of the portuguese coastal circulation is implemented with MOHID (1). The Mercator large-scale operational North-Atlantic ocean model (2) provides initial and one-way open boundary conditions, while the MM5 mesoscale regional atmospheric forecasting model, forced by ECMRWF data, provides surface forcing. T...

Introduction Foz do Arelho submarine outfall (-9.24 West and 39.44 North) located on the Western Portuguese coast 150 km north of Lisbon is the last organ of the inter municipal sewer system of Caldas da Rainha and Óbidos [1] (Figure 1). The system includes a network of 5 wastewater treatment plants performing secondary treatment and provides servi...