Computational strategies and visualisation techniques for the wave modelling in the Portuguese nearshore

2015

OCEANS 2015 - Genova

The objective of the work is to evaluate a data assimilation scheme for improving the reliability of the wave predictions in the Black Sea. A wave modeling system, SWAN based, has been implemented in the Black Sea and it was extensively tested against both in situ and remotely sensed measurements. Subsequently, this system was focused on various coastal environments in a multi-level nested scheme. In order to assimilate the satellite data, for the wave generation level that covers the entire basin of the Black Sea, an Optimal Interpolation (OI) technique has been implemented. SWAN model simulations have been performed covering a 10-year time interval (1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008). For this period, Hs measurements from the following satellites were available: ERS-2, Poseidon, JASON-1, JASON-2, GEOSAT Follow-On (GFO), ENVISAT, TOPEX. The assimilation technique was performed for a time window of 24h considering the first 5 satellites for assimilation and the last two (ENVISAT and TOPEX) for validations. The results show that the assimilation scheme implemented induces a visible improvement of all the statistical parameters evaluated, increasing in this way the reliability of the wave predictions. The work is still ongoing being focused on the prediction of the major storms and as a further step all the satellites will be considered for assimilation, while validations are going to be performed against various in situ measurements.

Section: Introductionmentioning

confidence: 83%

A data assimilation scheme to improve the wave predictions in the Black Sea

Butunoiu

2015

OCEANS 2015 - Genova

“…A multilevel, SWAN-based wave prediction system has been implemented and focused on the western side of the sea in a downscaling process [32][33][34][35]. Various sensitivity tests and validations have been carried out for each computational level [36], taking into account also the computational strategies adopted in other coastal environments where the model results have been intensively validated against in situ measurements and remotely sensed data [37]. A special attention was paid to the coastal areas with more complex coastal dynamics, as for example the mouths of the Danube River where strong interactions occur between the waves and currents generated by the Danube River outflow [38,39].…”

Section: Computational Levels Definedmentioning

confidence: 99%

Study of the Wave Energy Propagation Patterns in the Western Black Sea

2018

Applied Sciences

The most relevant patterns of the wave energy propagation in the western side of the Black Sea were assessed in the present work. The emphasis was put on the western side because this is also the most energetic part of the Black Sea. The assessments performed relate some recent results provided by a numerical wave modeling system based on the spectrum concept. The SWAN model (acronym for Simulating Waves Nearshore) was considered. This was implemented over the entire sea basin and focused with increasing resolution in the geographical space towards the Romanian nearshore. Furthermore, some data assimilation techniques have also been implemented, such that the results provided are accurate and reliable. Special attention was paid to the high, but not extreme, winter wave energy conditions. The cases considered are focused on the coastal waves generated by distant storms, which means the local wind has not very high values in the targeted areas. This also takes into account the fact that the configuration of the environmental matrix in the Black Sea is currently subjected to significant changes mainly due to the climate change. From this perspective, the present work illustrates some of the most recent patterns of wave energy propagation in the western side of the Black Sea, considering eight different SWAN computational domains. According to most of the recent evaluations, the nearshore of the Black Sea is characterized by an average wave power lower than 6 kW/m. The results of the present work show that there is a real tendency of the wave energy enhancement. This tendency, especially concerns the western side of the basin, where in the high conditions considered, values of the wave power about 10 times greater than the average have been noticed. despite some initial difficulties related to the high cost of installation and operating conditions in the harsh marine environment, very high dynamics in increasing the efficiency of the offshore wind can be also noticed. This is measured, especially through the levelized cost of energy (LCOE), which reached a record value of about 7 c€/kWh in 2017, or less. Thus, 5.5 c€/kWh have been reported at the 700 MW Borssele (The Netherlands) due to government tender and size, and 5c €/kWh (without transmission) at the 600 MW Kriegers Flak (Denmark) [2]. This means the offshore wind becomes now not only the cheapest marine renewable energy resource, but it is also cheaper than some traditional resources. For example, the current average LCOE for atomic energy is still about 11 c€/kWh, or greater [3].Various studies [4][5][6][7] showed that the wind energy resources along the coasts of the Black Sea, and especially in its western side, are comparable with those from many offshore wind farms that are already operational [8][9][10][11]. Thus, it is expected that the high dynamics of the offshore wind industry will have as a result also the implementation of some wind farm projects in the nearshore of the Black Sea, in general and in its western side, which is more energetic, in spe...

“…For the ocean scales, the most effective models are considered nowadays WAM (Wave Modeling), (WAMDI group, 1988) and WW3 (Wave Watch 3), (Tolman, 1992). Since for shallow water additional source terms are required, the nearshore spectral models are usually more complex than the ocean scale models (Rusu et al, 2005). Among these coastal models, SWAN (Simulating Waves Nearshore; Booij et al, 1999) is considered the state of the art.…”

Section: Implementation Of the Wave Prediction Systemmentioning

confidence: 99%

Reliability and Applications of the Numerical Wave Predictions in the Black Sea

2016

Front. Mar. Sci.

This work presents a review of the last developments in the numerical wave modeling in the basin of the Black Sea. A wave prediction system, based on the SWAN (Simulating Waves Nearshore) spectral model, has been implemented and focused on the western side of the sea. Various calibrations and validation tests have been performed considering both in situ and remotely sensed measurements. We found that the most critical factors in increasing the reliability of the wave predictions are related to the physical parameterizations of the model that should be adapted to the conditions of the enclosed seas, especially the process of whitecapping, and the accuracy and the resolution of the wind fields considered to force the wave model. Some data assimilation techniques have been also implemented for various computational levels and they were found very effective in improving the reliability of the wave predictions. Up to the present moment, some sequential methods have been applied considering several approaches as Optimal Interpolation, Linear Regression and Kalman Filter. Furthermore, some practical applications of the wave prediction system are also presented and discussed. These are related to the major storms that might be expected in the Black Sea. At this point, it has to be highlighted that an important issue when building an operational wave modeling system in such difficult environments, as the enclosed seas are, would be to implement different model configurations for different events (especially as regards the severe and extreme events). Other important issues concern the use of the wave models as a tool in the effort of preventing the sea and coastal hazards and assessing also the possible coastal impact of the marine energy farms that would operate in the nearshore. Renewable energy evaluations in the Black Sea have been also performed with this system. Finally, the results of the wave predictions were also used as input in some seakeeping studies.