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Registros recuperados: 7
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A note on the direct injection of turbulence by breaking waves ArchiMer
Rascle, Nicolas; Chapron, Bertrand; Ardhuin, Fabrice; Soloviev, Alexander.
We investigate the turbulence induced by wave-breaking at the ocean surface. Two recent models use a mechanism of direct depth injection of turbulent kinetic energy (TKE) by breaking waves. Those models aim to reproduce the near-surface mean and turbulent properties, in particular the TKE dissipation rates. Of critical importance are the injection depth of each breaking wave and the size distribution of those breaking waves. The models by Sullivan et al. (2007) and by Kudryavtsev et al. (2008) have very different parameterizations, and those differences are reviewed here and compared to available observations. Using realistic parameterizations in these models leads to TKE injections too shallow to compare to observations, in particular for developed seas....
Tipo: Text Palavras-chave: Surface waves; Wave breaking; Wave-induced turbulence; Vertical mixing; Mixed layer; Ekman currents.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00155/26581/25476.pdf
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A numerical study of tropical cyclone-induced sediment dynamics on the Australian North West Shelf ArchiMer
Dufois, Francois; Lowe, Ryan J.; Rayson, Matthew D.; Branson, Paul M..
Owing to their strong forcing of the ocean surface, tropical cyclones strongly modify the hydrodynamics of Australia's North West Shelf (one of the world's tropical cyclone hotspots), which in turn plays a dominant role in its sediment dynamics. Previous modeling studies have focused on describing the short term sediment dynamics during individual tropical cyclones, but have lacked validation of the responses using field observations. As a consequence, the long term cumulative impact of the tropical cyclones on the residual sediment transport pathways at the shelf scale remains unclear. In this study we apply a sediment transport model over the North West Shelf, validate its performance using an extensive field dataset, and implement a 14 year‐long model...
Tipo: Text Palavras-chave: ROMS; COAWST; Sediment transport model; Tropical cyclone; Surface waves; Sediment pathways.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00449/56078/57601.pdf
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Airborne Remote Sensing of Wave Propagation in the Marginal Ice Zone ArchiMer
Sutherland, Peter; Brozena, John; Rogers, W. Erick; Doble, Martin; Wadhams, Peter.
Airborne scanning lidar was used to measure the evolution of the surface wave field in the marginal ice zone (MIZ) during two separate wave events in the Beaufort Sea in October 2015. The lidar data consisted of a 2‐D field of surface elevation with horizontal resolutions between 17 and 33 cm, over a swath approximately 150‐220 m wide, centred on the ground track of the aircraft. Those data were used to compute directional wavenumber spectra of the surface wave field. Comparison with nearly collocated buoy data found the lidar and buoy measurements to be generally consistent. During the first event, waves travelling from open water into the ice were attenuated by the ice. The low spectral spreading and k7/4 spectral dependence of the attenuation was...
Tipo: Text Palavras-chave: Surface waves; Marginal ice zone; Wave attenuation; Wave growth rate; Air-sea-ice; Airborne scanning lidar.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00439/55086/56526.pdf
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HF Radar Activity in European Coastal Seas: Next Steps toward a Pan-European HF Radar Network ArchiMer
Rubio, Anna; Mader, Julien; Corgnati, Lorenzo; Mantovani, Carlo; Griffa, Annalisa; Novellino, Antonio; Quentin, Céline; Wyatt, Lucy; Schulz-stellenfleth, Johannes; Horstmann, Jochen; Lorente, Pablo; Zambianchi, Enrico; Hartnett, Michael; Fernandes, Carlos; Zervakis, Vassilis; Gorringe, Patrick; Melet, Angélique; Puillat, Ingrid.
High Frequency Radar (HFR) is a land-based remote sensing instrument offering a unique insight to coastal ocean variability, by providing synoptic, high frequency and high resolution data at the ocean atmosphere interface. HFRs have become invaluable tools in the field of operational oceanography for measuring surface currents, waves and winds, with direct applications in different sectors and an unprecedented potential for the integrated management of the coastal zone. In Europe, the number of HFR networks has been showing a significant growth over the past 10 years, with over 50 HFRs currently deployed and a number in the planning stage. There is also a growing literature concerning the use of this technology in research and operational oceanography. A...
Tipo: Text Palavras-chave: High frequency radar; Operational oceanography; Coastal observing systems; Radar remote sensing; Surface currents; Surface waves; Model assessment; Data assimilation.
Ano: 2017 URL: https://archimer.ifremer.fr/doc/00368/47879/47895.pdf
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Integrated Observations of Global Surface Winds, Currents, and Waves: Requirements and Challenges for the Next Decade ArchiMer
Villas Bôas, Ana B.; Ardhuin, Fabrice; Ayet, Alex; Bourassa, Mark A.; Brandt, Peter; Chapron, Bertrand; Cornuelle, Bruce D.; Farrar, J. T.; Fewings, Melanie R.; Fox-kemper, Baylor; Gille, Sarah T.; Gommenginger, Christine; Heimbach, Patrick; Hell, Momme C.; Li, Qing; Mazloff, Matthew R.; Merrifield, Sophia T.; Mouche, Alexis; Rio,; Rodriguez, Ernesto; Shutler, Jamie D.; Subramanian, Aneesh C.; Terrill, Eric J.; Tsamados, Michel; Ubelmann, Clement; Van Sebille, Erik.
Ocean surface winds, currents, and waves play a crucial role in exchanges of momentum, energy, heat, freshwater, gases, and other tracers between the ocean, atmosphere, and ice. Despite surface waves being strongly coupled to the upper ocean circulation and the overlying atmosphere, efforts to improve ocean, atmospheric, and wave observations and models have evolved somewhat independently. From an observational point of view, community efforts to bridge this gap have led to proposals for satellite Doppler oceanography mission concepts, which could provide unprecedented measurements of absolute surface velocity and directional wave spectrum at global scales. This paper reviews the present state of observations of surface winds, currents, and waves, and it...
Tipo: Text Palavras-chave: Air-sea interactions; Doppler oceanography from space; Surface waves; Absolute surface velocity; Ocean surface winds.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00509/62083/66271.pdf
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Onto a Skewness Approach to the Generalized Curvature Ocean Surface Scattering Model ArchiMer
Said, Faozi; Johnsen, Harald; Nouguier, Frederic; Chapron, Bertrand; Engen, Geir.
The generalized curvature ocean surface scattering model [general curvature model (GCM)] is extended and revisited. Two key steps are addressed in this paper, namely, a necessary sea surface spectrum undressing procedure and the inclusion of a skewness phase-related component. Normalized radar cross-section (NRCS) simulations are generated at C-band for various wind conditions, polarizations, and incidence angles. Results are compared with CMOD5.n. Although the sea surface spectrum undressing procedure is a necessary step, the overall NRCS dynamic is notably affected only in low wind conditions (<= 5 m/s). The inclusion of the skewness phase-related component makes the most impact to the NRCS dynamic where the upwind/downwind asymmetry is clearly...
Tipo: Text Palavras-chave: Geophysical measurements; Radar cross section; Remote sensing; Sea surface; Surface waves.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00409/52013/52725.pdf
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Wave Breaking in Slicks: Impacts on C-Band Quad-Polarized SAR Measurements ArchiMer
Wergeland, Morten; Kudryavtsev, Vladimir; Chapron, Bertrand; Brekke, Camilla; Johannessen, Johnny A..
Radarsat-2 C-band quad-polarization SAR observations of crude oil, emulsion, and plant oil slicks acquired in the wind speed range from 4 to 8 m/s and incidence angles from 30 degrees to 50 degrees are analyzed to yield new insights into the attenuation of short waves and breaking waves by surface slicks in real conditions. To provide a direct quantitative assessment of the surface wave damping, the measurements are decomposed into polarization difference (PD), polarization ratio (PR), nonpolarized (NP), and cross-polarized (CP) components. The PD signals relate to the extent of Bragg damping in the slick areas, over which the PR is systematically higher than over the ambient sea surface. Attenuation of the breaking waves is revealed to affect both the CP...
Tipo: Text Palavras-chave: Oil pollution; Radar imaging; Sea surface; Surface waves.
Ano: 2016 URL: https://archimer.ifremer.fr/doc/00363/47460/47484.pdf
Registros recuperados: 7
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