Ana Paula Falcão

Storm-Surge Hindcast at Viana do Castelo: An Oceanic and Estuarine Domain Approach

ABSTRACT Marujo, N.R.C.S.; Araújo, M.A.V.C., Trigo-Teixeira, A.; Falcão, A.P., and Mazzolari, A., 2014. Storm-surge hindcast at Viana do Castelo: An oceanic and estuarine domain approach. In the present work a storm-surge event, which occurred in Viana do Castelo (Portugal) on 14–17 October 1987, is modelled using the advanced circulation model (ADCIRC) . The main purpose of the work is to investigate the ability of ADCIRC to model storm-surge events in the region. Modelling this type of phenomena is of the utmost importance to comply with the European Union directive 2007/60/CE, concerning the assessment and risk management of floods, and to create risk charts used in coastal zone management. During this process, a strong emphasis was given to model calibration before storm-surge modelling. Preceding model calibration a field survey, using global navigation satellite system techniques, was carried out in the Lima Estuary to acquire lacking information required to build the corresponding digital terrain model (DTM). While modelling storm surge, two different domains were considered: a large oceanic and a smaller estuarine. For each of these domains, the model was calibrated with astronomy forcing using, respectively, the 6 and 10 most important tidal constituents, which were determined by harmonic analysis of the Viana do Castelo tidal gauge record. The friction coefficient, wave continuity, and lateral viscosity parameters were changed with this aim. Although the friction coefficient proved to be the most important calibration parameter, the other parameters are also important to achieve stable simulations. For the oceanic domain, the obtained results were improved by considering a variable Coriolis factor. Once the model was calibrated, it was forced using astronomy and meteorology jointly and separately. Atmospheric pressure, wind, and, for the estuarine domain, also river flow were considered as meteorological agents. The storm event was satisfactorily reproduced by the model and it was concluded that meteorology and astronomical effects interact nonlinearly. This nonlinearity is more pronounced when considering the river flow due to the tidal wave–current interaction.

Preliminary Results of Spatial Modelling of GPS/Levelling Heights: A Local Quasi-Geoid/Geoid for the Lisbon Area

Taking GPS-measured ellipsoidal heights with in situ measured gravity values, levelling-measured heights, and knowing the difference between normal gravity potential and geoidal potential, the calculation of normal heights is possible. The difference between normal and ellipsoidal heights allows the computation of gravity anomalies and geoid undulation, and thus the calculation of quasi-geoid and geoid surfaces, to serve practical applications such as large scale map production and engineering applications.

Methodology to Combine Topography and Bathymetry Data Sets for Hydrodynamic Simulations: Case of Tagus River

AbstractRecent techniques for acquiring elevation, such as the advanced synthetic aperture radar (SAR) interferometric techniques, enable the creation of very detailed models in a short time. However, because of its incapacity to penetrate the water, the collection of bathymetric information in water-covered areas must be performed with other techniques. Thus, data compatibility is a key factor for two-dimensional (2D) hydrodynamic simulations because a single elevation model is required in general. Such operation is often challenging, because it is not simply obtainable by merging the data sets or replacing the main river channel information with the bathymetry. This study presents a geographic information system (GIS)–based methodology to merge the bathymetry and topography of a river and validates it with 2D flood event simulations. Therefore, the floodplain topography data sets, including emerged fluvial features and profile-shaped bathymetric surveys covering only limited sections of the river channe...