404 research outputs found

    On the relative importance of the climate change factors along the river Scheldt considering climate scenarios for upstream inland and downstream coastal (mean sea level and surge) boundary conditions

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    To improve on the efficacy of flood risk mitigation measures, it is essential to investigate the relative importance of the future impact pressures. This is more so in areas which are found to be hot spots for flooding. One such area was identified in the Scheldt region located in Belgium. The Dendermonde area is a place where both the downstream coastal and the upstream river flow boundary conditions interact and jointly control the floodrisk. Downstream of this area, the coastal level changes include both the sea level rise and storm surge changes due to climate change impacts on the wind climate over the North Atlantic and North Sea region. Upstream of the Dendermonde area lies the Dender river which introduces an extra pressure on the Dendermonde area. Against this back drop, impact analysis was performed using a hydrodynamic model that accounts for such changes. The climate data for future scenarios were extracted from the climate databases PRUDENCE (http://prudence.dmi.dk),ENSEMBLES (http://www.ensembles-eu.org/), IPCC AR4 (www-pcmdi.llnl.gov/ipcc/about_ipcc.php) and CERA (CLM from MPI-M/MaD)

    Hydrodynamics and sediment transport. Fundamental aspects related to sustainable management of sandy coasts: aim and scope of the research project

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    The main scientific objectives of this research proposal can be summarised in the question why certain sandy coasts are dynamically stable and others are not. The following tools will be used to search for the answer:•Literature study•Building of a framework to model sediment transport in the near shore zone•Incorporation of the influence of complex spectra in the formulation of sediment transport influenced by currents and waves• Synergy of understanding of the physical processes (theoretical basis), numerical and physical modelling• Qualitative confrontation with available in situ measurementsSince we are convinced that the planned research activities are of international value, not only in terms of scientific merits but also from the point of view of sustainable coastal development, the following objectives form also part of this proposal:•Collaboration with other research teams in Europe who deal with this topic, for example by participating in experiments in the framework of TMR-LSF•Writing and submitting of a problem oriented and interdisciplinary research proposal to the E.U.•Dissimination of the results through conferences and by publication in international journal

    Evaluation of wind-wave generation formulations for separating wind sea and swell at the Gulf of Tehuantepec

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    Measurements of atmospheric and oceanographic parameters have been taken by the CICESE from an offshore location at the Gulf of Tehuantepec. The relevant features in the area are its particular meteorological and wave conditions. Due to a geographical depression of the mountain chain that goes along the isthmus a wind system ‘Tehuanos’ is formed. This wind system forces a sea that travels southwards offshore, where the wave climate is to a great extent dominated by the presence of swells that propagate typically northwards to the coast. Different methods for separating wind sea and swell have been tested. Namely (a) a constant split up frequency, (b) Drennan et al., formulation, (c) Komen et al. formulation, (d) Janssen’s theory which is the wind-wave generation mechanism of the WAM model, and (e) spectral partitioning in combination with (c). A constant split up frequency appears to be accurate in this case given that swell and wind sea systems are very well defined in the frequency domain. The use of spectral partitioning has also output satisfactory results. Inconsistencies due to the artificial splitting of the spectrum were found for methods (b), (c) and (d), for which the actual energy of the wind sea is not properly estimated. There was no substantial difference found on the energy-frequency evolution of wind seas for Tehuanos and non- Tehuanos winds
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