Consulta: subjectFacets:"General circulation models"
Registros recuperados: 5
Data/hora: 26/07/2024 22:10:56

A Lagrangian Method to Isolate the Impacts of Mixed Layer Subduction on the Meridional Overturning Circulation in a Numerical Model
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Thomas, Matthew; Treguier, Anne-marie; Blanke, Bruno; Deshayes, Julie; Voldoire, Aurore.
Large differences in the Atlantic meridional overturning circulation (AMOC) exhibited between the available ocean models pose problems as to how they can be interpreted for climate policy. A novel Lagrangian methodology has been developed for use with ocean models that enables a decomposition of the AMOC according to its source waters of subduction from the mixed layer of different geographical regions. The method is described here and used to decompose the AMOC of the Centre National de Recherches Météorologiques (CNRM) ocean model, which is approximately 4.5 Sv (1 Sv = 106 m3 s−1) too weak at 26°N, compared to observations. Contributions from mixed layer subduction to the peak AMOC at 26°N in the model are dominated by the Labrador Sea, which contributes...
Tipo: Text
Palavras-chave: Circulation; Dynamics; Convection; Lagrangian circulation; Transport; Meridional overturning circulation; Atm; Ocean Structure; Phenomena; Oceanic mixed layer; Models and modeling; General circulation models.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00284/39523/38016.pdf

Can We Infer Diapycnal Mixing Rates from the World Ocean Temperature-Salinity Distribution?
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Arzel, Olivier; Colin De Verdiere, Alain.
The turbulent diapycnal mixing in the ocean is currently obtained from microstructure and finestructure measurements, dye experiments, and inverse models. This study presents a new method that infers the diapycnal mixing from low-resolution numerical calculations of the World Ocean whose temperatures and salinities are restored to the climatology. At the difference of robust general circulation ocean models, diapycnal diffusion is not prescribed but inferred. At steady state the buoyancy equation shows an equilibrium between the large-scale diapycnal advection and the restoring terms that take the place of the divergence of eddy buoyancy fluxes. The geography of the diapycnal flow reveals a strong regional variability of water mass transformations....
Tipo: Text
Palavras-chave: Diapycnal mixing; Eddies; Meridional overturning circulation; Mixing; Ocean circulation; General circulation models.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00600/71197/69563.pdf

Deciphering the role of small-scale inhomogeneity on geophysical flow structuration: a stochastic approach
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Bauer, Werner; Chandramouli, Pranav; Chapron, Bertrand; Li, Long; Mémin, Etienne.
An important open question in fluid dynamics concerns the effect of smallscales in structuring a fluid flow. In oceanic or atmospheric flows, this is aptly captured in wave-current interactions through the study of the wellknown Langmuir secondary circulation. Such wave-current interactions are described by the Craik-Leibovich system, in which the action of a wave induced velocity, the Stokes drift, produces a so called “vortex force” that causes streaking in the flow. In this work, we show that these results can be generalized as a generic effect of the spatial inhomogeneity of the statistical properties of the small-scale flow components. As demonstrated, this is well captured through a stochastic representation of the flow.
Tipo: Text
Palavras-chave: Langmuir circulation; Baroclinic models; General circulation models; Stochastic models; Oscillations.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00610/72194/70975.pdf

Impact of multiple altimeter data and mean dynamic topography in a global analysis and forecasting system
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Hamon, Mathieu; Greiner, Eric; Le Traon, Pierre-yves; Remy, Elisabeth.
Satellite altimetry is one of the main sources of information used to constrain global ocean analysis and forecasting systems. In addition to in situ vertical temperature and salinity profiles, and Sea Surface Temperature (SST) data, Sea Level Anomalies (SLA) from multiple altimeters are assimilated through the knowledge of a surface reference, the Mean Dynamic Topography (MDT). The quality of analyses and forecasts mainly depends on the availability of SLA observations and on the accuracy of the MDT. A series of Observing System Evaluations (OSEs) were conducted to assess the relative importance of the number of assimilated altimeters and the accuracy of the MDT in a Mercator Ocean global ¼° ocean data assimilation system. Dedicated tools were used to...
Tipo: Text
Palavras-chave: Ocean; Sea level; Remote sensing; Forecast verification; Skill; Operational forecasting; General circulation models.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00502/61389/65053.pdf

Reconstructability of 3-Dimensional Upper Ocean Circulation from SWOT Sea Surface Height Measurements
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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