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| Registros recuperados: 11 | |
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| Wenegrat, Jacob O.; Thomas, Leif N.; Gula, Jonathan; Mcwilliams, James C.. |
| Non-conservative processes change the potential vorticity (PV) of the upper ocean, and later, through the subduction of surface waters into the interior, affect the general ocean circulation. Here we focus on how boundary layer turbulence, in the presence of submesoscale horizontal buoyancy gradients, generates a source of potential vorticity at the ocean surface through a balance known as the Turbulent ThermalWind. This source of PV injection at the submesoscale can be of similar magnitude to PV fluxes from the wind and surface buoyancy fluxes, and hence can lead to a net injection of PV onto outcropped isopycnals even during periods of surface buoyancy loss. The significance of these dynamics is illustrated using a high-resolution realistic model of the... |
| Tipo: Text |
Palavras-chave: Ageostrophic circulations; Atmosphere-ocean interaction; Fronts; Ocean dynamics; Potential vorticity; Boundary layer. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00452/56347/57937.pdf |
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| Moat, B. I.; Sinha, B.; Josey, S. A.; Robson, J.; Ortega, P.; Sévellec, Florian; Holliday, N. P.; Mccarthy, G. D.; New, A. L.; Hirschi, J. J.-m.. |
| An ocean mixed layer heat budget methodology is used to investigate the physical processes determining subpolar North Atlantic (SPNA) sea surface temperature (SST) and ocean heat content (OHC) variability on decadal-multidecadal timescales using the state-of-the-art climate model HadGEM3-GC2. New elements include development of an equation for evolution of anomalous SST for interannual and longer timescales in a form analogous to that for OHC, parameterization of the diffusive heat flux at the base of the mixed layer and analysis of a composite AMOC event. Contributions to OHC and SST variability from two sources are evaluated i) net ocean-atmosphere heat flux and ii) all other processes, including advection, diffusion and entrainment for SST. Anomalies in... |
| Tipo: Text |
Palavras-chave: Atmosphere-ocean interaction; Climate variability; Energy budget; Balance; Fluxes; Heat budgets; Fluxes; Surface temperature. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00502/61395/65060.pdf |
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| Macgilchrist, Graeme A.; Johnson, Helen L.; Marshall, David P.; Lique, Camille; Thomas, Matthew; Jackson, Laura C.; Wood, Richard A.. |
| A substantial fraction of the deep ocean is ventilated in the high-latitude North Atlantic. Consequently, the region plays a crucial role in transient climate change through the uptake of carbon dioxide and heat. However, owing to the Lagrangian nature of the process, many aspects of deep Atlantic Ocean ventilation and its representation in climate simulations remain obscure. We investigate the nature of ventilation in the high latitude North Atlantic in an eddy-permitting numerical ocean circulation model using a comprehensive set of Lagrangian trajectory experiments. Backwards-in-time trajectories from a model-defined ‘North Atlantic DeepWater’ (NADW) reveal the locations of subduction from the surface mixed layer at high spatial resolution. The major... |
| Tipo: Text |
Palavras-chave: North Atlantic Ocean; Atmosphere-ocean interaction; Lagrangian circulation/transport; Ocean circulation; Boundary currents; Diapycnal mixing. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00646/75833/76825.pdf |
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| Zippel, Seth F.; Maksym, Ted; Scully, Malcolm; Sutherland, Peter; Dumont, Dany. |
| Observations of waves, winds, turbulence, and the geometry and circulation of windrows were made in a shallow bay in the winter of 2018 outside of Rimouski, Québec. Water velocities measured from a forward-looking pulse-coherent ADCP mounted on a small zodiac show spanwise (cross-windrow) convergence, streamwise (downwind) velocity enhancement, and downwelling in the windrows, consistent with the view that windrows are the result of counter-rotating pairs of wind-aligned vortices. The spacing of windrows, measured with acoustic backscatter and with surface imagery, was measured to be approximately twice the water depth, which suggests an aspect ratio of 1. The magnitude and vertical distribution of turbulence measured from the ADCP are consistent with a... |
| Tipo: Text |
Palavras-chave: Ocean; Atmosphere-ocean interaction; Boundary layer; Langmuir circulation; In situ oceanic observations; Surface observations. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00593/70552/68722.pdf |
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| Kudryavtsev, Vladimir; Chapron, Bertrand. |
| The wave generation model based on the rapid distortion concept significantly underestimates empirical values of the wave growth rate. As suggested before, inclusion of the aerodynamic roughness modulations effect on the amplitude of the slope-correlated surface pressure could potentially reconcile this model approach with observations. This study explores the role of short-scale breaking modulations to amplify the growth rate of modulating longer waves. As developed, airflow separations from modulated breaking waves result in strong modulations of the turbulent stress in the inner region of the modulating waves. In turn, this leads to amplifying the slope-correlated surface pressure anomalies. As evaluated, such a mechanism can be very efficient for... |
| Tipo: Text |
Palavras-chave: Atm; Ocean Structure; Phenomena; Atmosphere-ocean interaction. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00313/42414/41759.pdf |
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| Cerovecki, Ivana; Talley, Lynne D.; Mazloff, Matthew R.; Maze, Guillaume. |
| Subantarctic Mode Water (SAMW) is examined using the data-assimilating, eddy-permitting Southern Ocean State Estimate, for 2005 and 2006. Surface formation due to air–sea buoyancy flux is estimated using Walin analysis, and diapycnal mixing is diagnosed as the difference between surface formation and transport across 30°S, accounting for volume change with time. Water in the density range 26.5 < σθ < 27.1 kg m−3 that includes SAMW is exported northward in all three ocean sectors, with a net transport of (18.2, 17.1) Sv (1 Sv ≡ 106 m3 s−1; for years 2005, 2006); air–sea buoyancy fluxes form (13.2, 6.8) Sv, diapycnal mixing removes (−14.5, −12.6) Sv, and there is a volume loss of (−19.3, −22.9) Sv mostly occurring in the strongest SAMW formation... |
| Tipo: Text |
Palavras-chave: Atmosphere-ocean interaction; Buoyancy; Fluxes; Ocean circulation. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00154/26487/24596.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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| Registros recuperados: 11 | |
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