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	Provedor de dados ArchiMer (4) Autor Ailliot, Pierre (2) Maisondieu, Christophe (2) Arnault, Sabine (1) Ashton, Ian (1) Chapron, Bertrand (1) Guede, Zakoua (1) Kpogo Nuwoklo, Komlan Agbéko (1) Kudryavtsev, Vladimir (1) Marie, Louis (1) Molemaker, Jeroen (1) Monbet, Valerie (1) Olagnon, Michel (1) Rascle, Nicolas (1) Saulnier, Jean Baptiste (1) Smith, George H. (1) Yurovskaya, Maria (1) Mais... Palavra-chave Directional wave spectrum (4) Aerial photography (1) Buoys array (1) Directional buoys (1) Drone (1) Field measurements (1) High resolution (1) Kriging (1) Maximum Likelihood Method (1) Maximum entropy method (1) Partitioning algorithm (1) Periodogram smoothing (1) Remote sensing observations (1) Sea state (1) Sea surface waves (1) Sequential Monte Carlo algorithm (1) Spectral estimation (1) Spectro-directional partitioning (1) Sunglitter (1) Wave stationarity/homogeneity (1) Mais... Tipo do documento Text (4) Ano 2018 (1) 2015 (1) 2013 (1) 2012 (1) País France (4) Idioma Inglês (4)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 4 Primeira ... 1 ... Última Improvement ocean wave spectra estimation using the temporal structure of wave systems ArchiMer Kpogo Nuwoklo, Komlan Agbéko; Ailliot, Pierre; Olagnon, Michel; Guede, Zakoua; Arnault, Sabine. Sea states are usually the combination of several time-evolving wave systems whereas the classical spectral estimation methods assume stationarity. A method that adapts to the dynamical evolution of the spectral components is proposed to improve both omnidirectional and directional sea wave spectral estimations. In this method, periodograms are computed for each sea state as in the conventional methods, and rather than only smoothing individual periodograms, the overall time-history of periodograms are simultaneously smoothed in frequency and time dimensions. Since a simple two dimensional averaging would not be appropriate because the temporal evolution of the wave systems reflects typical non-stationary behaviors, we use either kriging or adaptive 2D... Tipo: Text Palavras-chave: Directional wave spectrum; Spectral estimation; Periodogram smoothing; Kriging. Ano: 2015 URL: http://archimer.ifremer.fr/doc/00252/36309/37313.pdf Dynamical partitioning of directional ocean wave spectra ArchiMer Ailliot, Pierre; Maisondieu, Christophe; Monbet, Valerie. Directional wave spectra generally exhibit several peaks due to the coexistence of wind sea generated by local wind conditions and swells originating from distant weather systems. This paper proposes a new algorithm for partitioning such spectra and retrieving the various systems which compose a complex sea-state. It is based on a sequential Monte-Carlo algorithm which allows to follow the time evolution of the various systems. The proposed methodology is validated on both synthetic and real spectra and the results are compared with a method commonly used in the literature. Tipo: Text Palavras-chave: Partitioning algorithm; Directional wave spectrum; Sequential Monte Carlo algorithm. Ano: 2013 URL: http://archimer.ifremer.fr/doc/00134/24563/22688.pdf Refined sea state analysis from an array of four identical directional buoys deployed off the Northern Cornish coast (UK) ArchiMer Saulnier, Jean Baptiste; Maisondieu, Christophe; Ashton, Ian; Smith, George H.. This paper presents an analysis of sea states carried out from extended wave measurements realized near the Wave Hub wave energy test facility in Cornwall (UK). The space directional information is derived from the spectro-directional processing of time-domain data provided by an array of four independent SEAWATCH Mini II displacement buoys separated by an approximate average distance of 500 m. It is observed that, even though the size of the array is small compared to the local wave trains' length, the estimation of the directional spectra - using maximum entropy and likelihood methods - may sometimes exhibit certain space variability over the array. It was also observed that the tidal currents variations produced a significant influence upon the wave... Tipo: Text Palavras-chave: Directional wave spectrum; Directional buoys; Buoys array; Maximum entropy method; Maximum Likelihood Method; Sea state; Wave system; Spectro-directional partitioning; Wave stationarity/homogeneity; Wave/tide interactions. Ano: 2012 URL: http://archimer.ifremer.fr/doc/00098/20922/18739.pdf Wave spectrum retrieval from airborne sunglitter images ArchiMer Yurovskaya, Maria; Rascle, Nicolas; Kudryavtsev, Vladimir; Chapron, Bertrand; Marie, Louis; Molemaker, Jeroen. Reconstruction and evolution of two-dimensional spectra of surface waves in the Gulf of Mexico are derived from airborne sun-glitter imagery. As the proposed method is based on a linear transfer function deduced from the shape of the sunglitter brightness, the absolute wavenumber elevation spectrum does not require any additional assumption or information about sky brightness, wind or wave energy. The detailed description of the airborne image processing method is given. As demonstrated, retrieved spectra agree well with nearby NDBC buoy data, both for spectrum shape, level and energy angular distribution. The 180-degree wave direction ambiguity, inherent to image-derived spectra, is eliminated by using cross-correlation analysis between two consecutive... Tipo: Text Palavras-chave: Sunglitter; Sea surface waves; Directional wave spectrum; Aerial photography; Field measurements; Remote sensing observations; High resolution; Drone. Ano: 2018 URL: https://archimer.ifremer.fr/doc/00465/57712/60174.pdf Registros recuperados: 4 Primeira ... 1 ... Última

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