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| Registros recuperados: 13 | |
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| Rascle, Nicolas; Ardhuin, Fabrice. |
| A multi-scale global hindcast of ocean waves is presented that covers the years 1994-2012, based on recently published parameterizations for wind sea and swell dissipation [Ardhuin, F., Rogers, E., Babanin, A., Filipot, J.-F., Magne, R., Roland, A., van der Westhuysen, A., Queffeulou, P., Lefevre, J.-M., Aouf, L., Collard, F., 2010. Semi-empirical dissipation source functions for wind-wave models: Part I. Definition, calibration and validation. J. Phys. Oceanogr. 40 (9), 1917-1941]. Results from this hindcast include traditional wave parameters, like the significant wave height and mean periods, and we particularly consider the accuracy of the results for phenomenal sea states, with significant heights above 14 m. Using unbiased winds, there is no evidence... |
| Tipo: Text |
Palavras-chave: Waves; Hindcast; Air-sea fluxes; Stokes drift; Mean square slope; Seismic noise. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00155/26582/25477.pdf |
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| Nouguier, Frederic; Mouche, Alexis; Rascle, Nicolas; Chapron, Bertrand; Vandemark, Douglas. |
| Global colocalized ocean surface measurements using the Global Precipitation Measurement near-nadir dual-frequency Ku- and Ka-band microwave measurements are analyzed and compared. Focusing on the Ka and Ku cross-sections fall-off with incidence angles, the contemporaneous measurements enable to more precisely document differing ocean scattering characteristics for both microwave frequencies. Sensitivity with wind speed and significant wave height is further reported using global comparisons with numerical estimates. As demonstrated, the bifrequency capability can provide direct means to efficiently separate short-scale wave contributions, between mean squared slope and curvature characteristics, and to further gain valuable insights concerning near-nadir... |
| Tipo: Text |
Palavras-chave: Microwave; Radar cross section; Scattering; Spaceborne radar. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00352/46334/47128.pdf |
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| Ardhuin, Fabrice; Rascle, Nicolas; Belibassakis, K. A.. |
| Ardhuin et al. (2008) gave a second-order approximation in the wave slope of the exact Generalized Lagrangian Mean (GLM) equations derived by Andrews and McIntyre (1978), and also performed a coordinate transformation, going from a from GLM to a ’GLMz’ set of equations. That latter step removed the wandering of the GLM mean sea level away from the Eulerian-mean sea level, making the GLMz flow non-divergent. That step contained some inaccuarate statements about the coordinate transformation, while the rest of the paper contained an error on the surface dynamic boundary condition for viscous stresses. I am thankful to Mathias Delpey and Hidenori Aiki for pointing out these errors, which are corrected below. |
| Tipo: Text |
Palavras-chave: Wave-current; GLM; Air-sea. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00380/49165/49601.pdf |
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| Morrow, Rosemary; Fu, Lee-lueng; Ardhuin, Fabrice; Benkiran, Mounir; Chapron, Bertrand; Cosme, Emmanuel; D’ovidio, Francesco; Farrar, J. Thomas; Gille, Sarah T.; Lapeyre, Guillaume; Le Traon, Pierre-yves; Pascual, Ananda; Ponte, Aurelien; Qiu, Bo; Rascle, Nicolas; Ubelmann, Clement; Wang, Jinbo; Zaron, Edward D.. |
| The future international Surface Water and Ocean Topography (SWOT) Mission, planned for launch in 2021, will make high-resolution 2D observations of sea-surface height using SAR radar interferometric techniques. SWOT will map the global and coastal oceans up to 77.6∘ latitude every 21 days over a swath of 120 km (20 km nadir gap). Today’s 2D mapped altimeter data can resolve ocean scales of 150 km wavelength whereas the SWOT measurement will extend our 2D observations down to 15–30 km, depending on sea state. SWOT will offer new opportunities to observe the oceanic dynamic processes at scales that are important in the generation and dissipation of kinetic energy in the ocean, and that facilitate the exchange of energy between the ocean interior and the... |
| Tipo: Text |
Palavras-chave: Ocean mesoscale circulation; Satellite altimetry; SAR-interferometry; Tides and internal tides; Calibration-validation. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00495/60685/64181.pdf |
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| Rascle, Nicolas; Molemaker, Jeroen; Marie, Louis; Nouguier, Frederic; Chapron, Bertrand; Lund, Bjorn; Mouche, Alexis. |
| Fine scale current gradients at the ocean surface can be observed by sea surface roughness. More specifically, directional surface roughness anomalies are related to the different horizontal current gradient components. This paper reports results from a dedicated experiment during the LASER (LAgrangian Submesoscale ExpeRiment) drifter deployment. A very sharp front, 50 m wide, is detected simultaneously in drifter trajectories, sea surface temperature and sea surface roughness. A new observational method is applied, using sun glitter reflections during multiple airplane passes to reconstruct the multi-angle roughness anomaly. This multi-angle anomaly is consistent with wave-current interactions over a front, including both cross-front convergence and... |
| Tipo: Text |
Palavras-chave: Sea surface roughness; Surface current; Remote sensing; Sun glitter; High resolution; Oceanic fronts. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00386/49767/50301.pdf |
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| Rascle, Nicolas; Chapron, Bertrand; Molemaker, Jeroen; Nouguier, Frederic; Ocampo‐torres, Francisco J.; Osuna Cañedo, J. Pedro; Marié, Louis; Lund, Björn; Horstmann, Jochen. |
| Sea surface roughness is affected by surface current gradients, which provides a means of monitoring from satellite sharp oceanic fronts. This paper is the second report of an experiment designed to compare observations of sea surface roughness and surface currents at an unprecedented accuracy, owing to the conjunction of numerous deployed drifters and roughness instruments. About 200 drifters sampled a thin 10~km elongated submesoscale front, also monitored by a high density of roughness instruments: satellite Synthetic Aperture Radar, satellite and airborne multi‐angle sunglint radiometers. The first paper focused on the retrieval of the current gradient direction (convergence and cyclonic vorticity) at the front, using roughness observations at multiple... |
| Tipo: Text |
Palavras-chave: Sea surface roughness; Submesoscale current; Fine-scale current; Synthetic aperture radar (SAR); Sunglint Sun glitter; Ocean front. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00636/74788/75035.pdf |
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| Ardhuin, Fabrice; Gille, Sarah T.; Menemenlis, Dimitris; Rocha, Cesar B.; Rascle, Nicolas; Chapron, Bertrand; Gula, Jonathan; Molemaker, Jeroen. |
| Tidal currents and large-scale oceanic currents are known to modify ocean wave properties, causing extreme sea states that are a hazard to navigation. Recent advances in the understanding and modeling capability of open ocean currents have revealed the ubiquitous presence of eddies, fronts and filaments at scales 10 to 100∼km. Based on realistic numerical models, we show that these structures can be the main source of variability in significant wave heights at scales less than 200 km, including important variations down to 10 km. Model results are consistent with wave height variations along satellite altimeter tracks, resolved at scales larger than 50 km. The spectrum of significant wave heights is found to be of the order of 70〈Hs〉2/(g2〈Tm0,-1〉2) times... |
| Tipo: Text |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00382/49328/49708.pdf |
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| Rascle, Nicolas; Nouguier, Frederic; Chapron, Bertrand; Ocampo-torres, Francisco J.. |
| High-resolution satellite images of the ocean surface in and around the sunglint often provide unique observations of sub-mesoscale upper ocean surface processes. Local anomalies of wind, waves, currents or surfactants appear on the images as local anomalies of brightness. A quantitative interpretation of those brightness anomalies must relate them to slope properties of the wave field, which are to the lowest order described by the mean square slope (mss). The prevailing paradigm for such interpretation is that of the critical zenith angle. It states that, for sub-critical zenith view angle, brightness and mss anomalies have opposite signs, and this defines the so-called inversion region. This prevailing paradigm implicitly builds on the assumption that... |
| Tipo: Text |
Palavras-chave: Sea surface roughness; Surface current gradients; Submesoscale turbulence; Wave-current interaction; Surfactants; Sun glint imagery; SAR images; Multi-angle radiometers; Surface slope distribution; Mean square slope. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00448/55964/57498.pdf |
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| Rascle, Nicolas; Nouguier, Frederic; Chapron, Bertrand; Mouche, Alexis; Ponte, Aurelien. |
| At times, high resolution images of sea surface roughness can provide stunning details of submesoscale upper ocean dynamics. As interpreted, transformations of short scale wind waves by horizontal current gradients are responsible for those spectacular observations. Those observations could prove particularly useful to validate numerical ocean models which reach increasingly high resolutions. Focusing on surface roughness at optical wavelengths, two steps have recently been performed in that direction. First, it was shown by Rascle et al. (2014, Journal of Physical Oceanography) that surface roughness variations not only trace surface current divergence but also other characteristics of the current gradient tensor, mainly the strain in the wind direction.... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00358/46878/46759.pdf |
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| 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 |
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| Registros recuperados: 13 | |
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