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| Registros recuperados: 11 | |
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| Ponte, Aurelien; Klein, Patrice; Capet, Xavier; Le Traon, Pierre-yves; Chapron, Bertrand; Lherminier, Pascale. |
| High-resolution numerical experiments of ocean mesoscale eddy turbulence show that the wind-driven mixed layer (ML) dynamics affects mesoscale motions in the surface layers at scales lower than O(60 km). At these scales, surface horizontal currents are still coherent to, but weaker than, those derived from sea surface height using geostrophy. Vertical motions, on the other hand, are stronger than those diagnosed using the adiabatic quasigeotrophic (QG) framework. An analytical model, based on a scaling analysis and on simple dynamical arguments, provides a physical understanding and leads to a parameterization of these features in terms of vertical mixing. These results are valid when the wind-driven velocity scale is much smaller than that associated with... |
| Tipo: Text |
Palavras-chave: Mesoscale processes; Ocean dynamics; Turbulence. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00170/28076/26291.pdf |
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| Jullien, Swen; Masson, Sébastien; Oerder, Véra; Samson, Guillaume; Colas, François; Renault, Lionel. |
| Ocean mesoscale eddies are characterized by rotating-like and meandering currents that imprint the low-level atmosphere. Such a current feedback (CFB) has been shown to induce a sink of energy from the ocean to the atmosphere, and consequently to damp the eddy kinetic energy (EKE), with an apparent regional disparity. In a context of increasing model resolution, the importance of this feedback, and its dependence on oceanic and atmospheric models resolution arise. Using a hierarchy of quasi-global coupled models with spatial resolutions varying from ¼° to 1/12°, the present study shows that the CFB induces a negative wind work at scales ranging from 100 to 1000 km, and a subsequent damping of the mesoscale activity by ∼30% on average, independently of the... |
| Tipo: Text |
Palavras-chave: Currents; Feedback; Mesoscale processes; Air-sea interaction; Coupled models; Mesoscale models. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00601/71329/69759.pdf |
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| Fan, Xue; Send, Uwe; Testor, Pierre; Karstensen, Johannes; Lherminier, Pascale. |
| Mesoscale anticyclonic eddies in the Irminger Sea are observed using a mooring and a glider. Between 2002 and 2009, the mooring observed 53 anticyclones. Using a kinematic model, objective estimates of eddy length scales and velocity structure are made for 16 eddies. Anticyclones had a mean core diameter of 12 km, and their mean peak observed azimuthal speed was 0.1 m s(-1). They had core salinities and potential temperatures of 34.91-34.98 and 4.488-5.34 degrees C, respectively, making them warm and salty features. These properties represent a typical salinity anomaly of 0.03 and a temperature anomaly of 0.28 degrees C from noneddy values. All eddies had small (<< 1) Rossby numbers. In 2006, the glider observed two anticyclones having diameters of... |
| Tipo: Text |
Palavras-chave: North Atlantic Ocean; Eddies; Mesoscale processes. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00137/24832/22921.pdf |
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| Qiu, Bo; Chen, Shuiming; Klein, Patrice; Torres, Hector; Wang, Jinbo; Fu, Lee-lueng; Menemenlis, Dimitris. |
| Reconstructability of upper ocean vertical velocity (w) and vorticity (ζ) fields from high-resolution sea surface height (SSH) data is explored using the global 1/48° horizontal-resolution MITgcm output in the context of the forth-coming Surface Water and Ocean Topography (SWOT) mission. By decomposing w with an omega equation of the primitive-equation system and by taking into account the measurement design of the SWOT mission, this study seeks to reconstruct the subinertial, balanced w and ζ signals. By adopting the effective surface quasi-geostrophic (eSQG) framework and applying to the Kuroshio Extension region of the North Pacific, we find that the target and reconstructed fields have a spatial correlation of ~0.7 below the mixed layer for w and 0.7 ~... |
| Tipo: Text |
Palavras-chave: Eddies; Mesoscale processes; Ocean dynamics; Vertical motion; Altimetry. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00593/70561/68744.pdf |
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| Qiu, Bo; Chen, Shuiming; Klein, Patrice; Sasaki, Hideharu; Sasai, Yoshikazu. |
| Located at the center of the western North Pacific Subtropical Gyre, the Subtropical Countercurrent (STCC) is not only abundant in mesoscale eddies, but also exhibits prominent submesoscale eddy features. Output from a 1/30 degrees high-resolution OGCM simulation and a gridded satellite altimetry product are analyzed to contrast the seasonal STCC variability in the mesoscale versus submesoscale ranges. Resolving the eddy scales of >150 km, the altimetry product reveals that the STCC eddy kinetic energy and rms vorticity have a seasonal maximum in May and April, respectively, a weak positive vorticity skewness without seasonal dependence, and an inverse (forward) kinetic energy cascade for wavelengths larger (shorter) than 250 km. In contrast, the... |
| Tipo: Text |
Palavras-chave: Circulation/ Dynamics; Eddies; Instability; Mesoscale processes; Observational techniques and algorithms; Altimetry; Models and modeling; Ocean models; Variability; Seasonal variability. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00245/35588/34142.pdf |
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| Villas Bôas, Ana B.; Cornuelle, Bruce. D.; Mazloff, Matthew. R.; Gille, Sarah. T.; Ardhuin, Fabrice. |
| Surface gravity waves play a major role in the exchange of momentum, heat, energy, and gases between the ocean and the atmosphere. The interaction between currents and waves can lead to variations in the wave direction, frequency, and amplitude. In the present work, we use an ensemble of synthetic currents to force the wave model WAVEWATCH III and assess the relative impact of current divergence and vorticity in modifying several properties of the waves, including direction, period, directional spreading, and significant wave height (Hs). We find that the spatial variability of Hs is highly sensitive to the nature of the underlying current and that refraction is the main mechanism leading to gradients of Hs. The results obtained using synthetic currents... |
| Tipo: Text |
Palavras-chave: Ocean; Sea/ocean surface; Atmosphere-ocean interaction; Mesoscale processes; Waves; Oceanic; Numerical analysis/modeling. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00654/76592/77740.pdf |
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| Qiu, Bo; Chen, Shuiming; Klein, Patrice; Ubelmann, Clement; Fu, Lee-lueng; Sasaki, Hideharu. |
| Utilizing the framework of effective surface quasi-geostrophic (eSQG) theory, we explored the potential of reconstructing the 3D upper ocean circulation structures, including the balanced vertical velocity (w) field, from high-resolution sea surface height (SSH) data of the planned SWOT satellite mission. Specifically, we utilized the 1/30°, submesoscale-resolving, OFES model output and subjected it through the SWOT simulator that generates the along-swath SSH data with expected measurement errors. Focusing on the Kuroshio Extension region in the North Pacific where regional Rossby numbers range from 0.22 to 0.32, we found that the eSQG dynamics constitutes an effective framework for reconstructing the 3D upper ocean circulation field. Using the modeled... |
| Tipo: Text |
Palavras-chave: Variability; Models and modeling; General circulation models; Vertical motion; Circulation/ Dynamics; Quasigeostrophic models; Mesoscale processes; Observational techniques and algorithms; Oceanic variability; Altimetry. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00309/42032/41331.pdf |
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| Registros recuperados: 11 | |
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