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| Registros recuperados: 129 | |
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| Gualtieri, L; Stutzmann, E; Juretzek, C; Hadziioannou, C; Ardhuin, Fabrice. |
| Primary microseism is the less studied seismic background vibration of the Earth. Evidence points to sources caused by ocean gravity waves coupling with the seafloor topography. As a result, these sources should be in water depth smaller than the wavelength of ocean waves. Using a state-of-the-art ocean wave model, we carry out the first global-scale seismic modeling of the vertical-component power spectral density of primary microseisms. Our modeling allows us to infer that the observed weak seasonality of primary microseisms in the southern hemisphere corresponds to a weak local seasonality of the sources. Moreover, a systematic analysis of the source regions that mostly contribute to each station reveals that stations on both the East and West sides of... |
| Tipo: Text |
Palavras-chave: Numerical modelling; Computational seismology; Seismic noise; Theoretical Seismology. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00487/59842/62990.pdf |
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| Ardhuin, Fabrice; Herbers, T. H. C.. |
| Oceanic pressure measurements, even in very deep water, and atmospheric pressure or seismic records, from anywhere on Earth, contain noise with dominant periods between 3 and 10 s, which is believed to be excited by ocean surface gravity waves. Most of this noise is explained by a nonlinear wave-wave interaction mechanism, and takes the form of surface gravity waves, acoustic or seismic waves. Previous theoretical work on seismic noise focused on surface (Rayleigh) waves, and did not consider finite-depth effects on the generating wave kinematics. These finite-depth effects are introduced here, which requires the consideration of the direct wave-induced pressure at the ocean bottom, a contribution previously overlooked in the context of seismic noise. That... |
| Tipo: Text |
Palavras-chave: Acoustics; Geophysical and geological flows; Surface gravity waves. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00125/23580/21479.pdf |
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| Pineau-guillou, Lucia; Dumas, Franck; Theetten, Sebastien; Ardhuin, Fabrice; Lecornu, Fabrice; Le Roux, Jean-francois; Idier, Deborah; Muller, Heloise; Pedreros, Rodrigo. |
| The pre-operational system PREVIMER provides coastal observations and forecasts along French coasts. It provides, among other variables, currents, sea levels, surges and waves. This paper describes the development and validation of a high temporal (15 minutes) and spatial (250 m) resolution modeling system, based on MARS hydrodynamic model (Lazure and Dumas 2008), along the Atlantic and English Channel coasts. Models benefi t from experiments developed during the PREVIMER project by: (1) taking better into account wind and wave actions (improving surface drag coeffi cient parameterization), (2) taking into account a better meteorological forcing (improving spatial and temporal meteorological resolution). These high resolution models have been integrated in... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00189/30036/28522.pdf |
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| Stopa, Justin; Ardhuin, Fabrice; Chapron, Bertrand; Collard, Fabrice. |
| It has been long accepted that ocean wave conditions recorded from synthetic aperture radar (SAR) aboard satellites resolve large scale swells. SARs make use of its displacement to achieve fine resolution; however the random surface motions can reduce its nominal azimuthal resolution. Accordingly, the SAR spectral azimuth response mirrors the probability distribution of the radial velocity component of the scatters. This effect, quantified in a measure called the azimuth cutoff, is estimated by defining a scale based on the fitting of a Gaussian function to the radar cross section azimuth spectrum. The independent measure provides additional sea state information related to the root mean square surface orbital wave velocity. We use data recorded from the... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00310/42170/41471.pdf |
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| Voldoire, Aurore; Decharme, Bertrand; Pianezze, Joris; Brossier, Cindy Lebeaupin; Sevault, Florence; Seyfried, Leo; Garnier, Valerie; Bielli, Soline; Valcke, Sophie; Alias, Antoinette; Accensi, Mickael; Ardhuin, Fabrice; Bouin, Marie-noelle; Ducrocq, Veronique; Faroux, Stephanie; Giordani, Herve; Leger, Fabien; Marsaleix, Patrick; Rainaud, Romain; Redelsperger, Jean-luc; Richard, Evelyne; Riette, Sebastien. |
| This study presents the principles of the new coupling interface based on the SURFEX multi-surface model and the OASIS3-MCT coupler. As SURFEX can be plugged into several atmospheric models, it can be used in a wide range of applications, from global and regional coupled climate systems to high-resolution numerical weather prediction systems or very fine-scale models dedicated to process studies. The objective of this development is to build and share a common structure for the atmosphere-surface coupling of all these applications, involving on the one hand atmospheric models and on the other hand ocean, ice, hydrology, and wave models. The numerical and physical principles of SURFEX interface between the different component models are described, and the... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00412/52391/53239.pdf |
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| Ardhuin, Fabrice; Roland, Aron; Dumas, Franck; Bennis, Anne-claire; Sentchev, Alexei; Forget, Philippe; Wolf, Judith; Girard, Francoise; Osuna, Pedro; Benoit, Michel. |
| Currents effects on waves have led to many developments in numerical wave modeling over the past two decades, from numerical choices to parameterizations. The performance of numerical models in conditions with strong currents is reviewed here, and observed strong effects of opposed currents and modulations of wave heights by tidal currents in several typical situations are interpreted. For current variations on small scales, the rapid steepening of the waves enhances wave breaking. Using different parameterizations with a dissipation rate proportional to some measure of the wave steepness to the fourth power, the results are very different, none being fully satisfactory, which points to the need for more measurements and further refinements of... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00130/24159/22254.pdf |
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| Ardhuin, Fabrice; Orfila, Alejandro. |
| Wind-generated waves dominate sea surface motions for periods shorter than 300 seconds. Waves are of interest for many applications ranging from navigation safety to ocean and coastal engineering. Waves also define air-sea fluxes and have important interactions with surface currents, upper ocean turbulence, and sea ice. Given the general focus of this book, we emphasize here the successes of wave forecasting methods, starting with a review of basic principles and how wave energy and momentum are modeled. In particular, we discuss the connection between wave modeling and remote sensing, and opportunities for joint measurements of currents and waves. A more detailed account of wave research and applications to geosciences can be found in Ardhuin (2018) |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00461/57251/59264.pdf |
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| Leckler, Fabien; Ardhuin, Fabrice; Peureux, Charles; Benetazzo, Alvise; Bergamasco, Filippo; Dulov, Vladimir. |
| The energy level and its directional distribution are key observations for understanding the energy balance in the wind-wave spectrum between wind-wave generation, nonlinear interactions, and dissipation. Here, properties of gravity waves are investigated from a fixed platform in the Black Sea, equipped with a stereo video system that resolves waves with frequency f up to 1.4 Hz and wavelengths from 0.6 to 11 m. One representative record is analyzed, corresponding to young wind waves with a peak frequency fp = 0.33 Hz and a wind speed of 13 m s−1. These measurements allow for a separation of the linear waves from the bound second-order harmonics. These harmonics are negligible for frequencies f up to 3 times fp but account for most of the energy at higher... |
| Tipo: Text |
Palavras-chave: Circulation; Dynamics; Waves; Oceanic; Observational techniques and algorithms; Remote sensing. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00284/39524/38017.pdf |
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| Farra, V.; Stutzmann, Eleonore; Gualtieri, Lucia; Schimmel, M.; Ardhuin, Fabrice. |
| Secondary microseism sources are pressure fluctuations close to the ocean surface. They generate acoustic P-waves that propagate in water down to the ocean bottom where they are partly reflected, and partly transmitted into the crust to continue their propagation through the Earth. We present the theory for computing the displacement power spectral density of secondary microseism P-waves recorded by receivers in the far field. In the frequency domain, the P-wave displacement can be modeled as the product of (1) the pressure source, (2) the source site effect that accounts for the constructive interference of multiply reflected P-waves in the ocean, (3) the propagation from the ocean bottom to the stations, (4) the receiver site effect. Secondary microseism... |
| Tipo: Text |
Palavras-chave: Seismic interferometry; Body waves; Seismic noise; Wave propagation. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00344/45509/45063.pdf |
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| Collard, Fabrice; Ardhuin, Fabrice; Chapron, Bertrand. |
| Satellite synthetic aperture radar (SAR) observations can provide a global view of ocean swell fields when using a specific "wave mode" sampling. A methodology is presented to routinely derive integral properties of the longer-wavelength ( swell) portion of the wave spectrum from SAR level 2 products and both monitor and predict their evolution across ocean basins. SAR-derived estimates of swell height and energy-weighted peak period and direction are validated against buoy observations, and the peak directions are used to project the peak periods in one dimension along the corresponding great circle route, both forward and back in time, using the peak period group velocity. The resulting real-time data set of great circle-projected peak periods produces... |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00000/11101/7417.pdf |
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| Autret, Ronan; Dodet, Guillaume; Fichaut, Bernard; Suanez, Serge; David, Laurence; Leckler, Fabien; Ardhuin, Fabrice; Ammann, Jerome; Grandjean, Philippe; Allemand, Pascal; Filipot, Jean-francois. |
| Large clastic cliff-top storm deposits (called CTSDs) are one of the most remarkable signatures that characterizes extreme storm wave events on coastal cliffs. Hence, the study of CTSDs is of key importance for understanding and predicting the impacts of extreme storm wave events on rocky coasts or establishing proxies for storm intensity. The present study uses new data including hydrodynamic measurements in both deep and intertidal waters, and records of CTSDs displacement and deposition across Banneg Island during the stormy winter 2013–2014. Two drone-based surveys were carried out in January 2013 (pre-storms) and in April 2014 (post-storms). In addition, complementary field observations were carried out during the winter, providing a comprehensive and... |
| Tipo: Text |
Palavras-chave: Cliff-top storm deposit; Block transport; Extra-tropical cyclone; Run-up; Coastal erosion; Brittany. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00353/46411/46139.pdf |
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| Verney, Romaric; Jany, Cassandre; Thouvenin, Benedicte; Pairaud, Ivane; Vousdoukas, Michalis I.; Pinazo, Christel; Ardhuin, Fabrice; Cann, Philippe. |
| Human pressures on ecosystems have increased significantly over the last decades, and especially Mediterranean coasts are strongly impacted by the development of big cities and industrialized area, such as the Bay of Marseille. Prior to any investigations on ecological or contamination impacts, it was necessary to understand sediment dynamics and its response to natural extreme events such as storm or heavy rainfall events. In situ observations were dedicated to understand the behavior of bed sediments, and their spatial distribution. A benthic station was deployed for three months to observe the impact of extreme events on hydrodynamics and sediment dynamics in a critical zone of the study area. These measurementswere used to calibrate and validate the... |
| Tipo: Text |
Palavras-chave: Sediment dynamics; Large coastal cities; Urban pressure; Extreme events; Wave; Rainfall; Marseille. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00204/31515/29929.pdf |
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| Bertin, Xavier; De Bakker, Anouk; Van Dongeren, Ap; Coco, Giovanni; Andre, Gael; Ardhuin, Fabrice; Bonneton, Philippe; Bouchette, Frederic; Castelle, Bruno; Crawford, Wayne C.; Davidson, Mark; Deen, Martha; Dodet, Guillaume; Guerin, Thomas; Inch, Kris; Leckler, Fabien; Mccall, Robert; Muller, Heloise; Olabarrieta, Maitane; Roelvink, Dano; Ruessink, Gerben; Sous, Damien; Stutzmann, Eleonore; Tissier, Marion. |
| Infragravity (hereafter IG) waves are surface ocean waves with frequencies below those of wind-generated "short waves" (typically be- low 0.04 Hz). Here we focus on the most common type of IG waves, those induced by the presence of groups in incident short waves. Three related mechanisms explain their generation: (1) the development, shoaling and release of waves bound to the short-wave group envelopes (2) the modulation by these envelopes of the location where short waves break, and (3) the merging of bores (breaking wave front, resembling to a hydraulic jump) inside the surfzone. When reaching shallow water (O(1-10 m)), IG waves can transfer part of their energy back to higher frequencies, a process which is highly dependent on beach slope. On gently... |
| Tipo: Text |
Palavras-chave: Infragravity waves; Bound wave; Dissipation; Reflection; Sediment transport; Barrier breaching; Seiche; Earth hum. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00417/52876/53800.pdf |
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| Ardhuin, Fabrice; Balanche, Abel; Stutzmann, E.; Obrebski, Mathias. |
| Seismic noise is an indirect source of information on ocean waves. Using a model of noise generation and propagation, seismic stations can be separated into those that are mostly sensitive to local sea states, and those that integrate sources from a large oceanic area. The model also provides a classification of noise-generating sea states into three classes. The analysis of Central California seismic noise data, well correlated with local waves, reveals that class I events dominate in summer, caused by a single wind-sea system, and for which ocean wave spectral levels are proportional to seismic spectral levels to an exponent b similar or equal to 0.9. In winter, noise is dominated by class II generation, for which coastal reflection is important, with a... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00083/19443/17051.pdf |
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| Rawat, Arshad; Ardhuin, Fabrice; Ballu, Valerie; Crawford, Wayne; Corela, Carlos; Aucan, Jerome. |
| Ocean infragravity (IG) waves are low-frequency waves generated along shorelines by incident seas and swell and with heights of the order of 1 cm in the open ocean. Despite these small amplitudes, they can be of much importance for ice shelf break up and errors in measurements of sea level by future satellite altimeters. A combination of numerical model results and in situ data is used to show that bottom pressure signals in the infragravity frequency band can be dominated by bursts of energy that travel across ocean basins, and can last for several days. Two particularly strong events recorded in 2008 are studied, one in the North-Pacific and the other in the North-Atlantic. It is shown that infragravity waves can travel across whole oceans basins with... |
| Tipo: Text |
Palavras-chave: Infragravity waves; DART; Global wave model. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00233/34465/32860.pdf |
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| Registros recuperados: 129 | |
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