Isopycnal Mixing in Ocean Circulation Models

Gent, Peter R.; McWilliams, James C.

doi:10.1175/1520-0485(1990)020<0150:imiocm>2.0.co;2

Cited by 2,907 publications

(2,309 citation statements)

References 10 publications

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“…(2) Biharmonic viscosity and diffusivity schemes are used at the horizontal directions in the equations of momentums and tracers (temperature and salinity), respectively. Meanwhile, the parameterization of mesoscale eddies from Gent and McWilliams [18] is turned off in the equations of tracers.…”

Section: Model Description and Experimentsmentioning

confidence: 99%

Indonesian Throughflow in an eddy-resolving ocean model

et al. 2013

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The performance of the eddy-resolving LICOM2.0 in simulating the Indonesian Throughflow has been evaluated against the INSTANT data in the present study. The mean vertical structures of the along strait velocities are simulated well in LICOM2.0, but the large velocities at the bottom of the Lifamatola Passage and the Timor Passage cannot be reproduced by LICOM2.0. The causes are considered to be both the errors in the topography and the tidal mixing at the bottom. Despite several biases in the mean velocities, the mean inflow and outflow volume transports in LICOM2.0 are almost identical to the INSTANT data. Compared with the lower resolution LICOM, the most significant improvement is the better simulation of the partitions of the inflow and outflow transports in individual straits. The outflow for low-resolution LICOM is mainly through the Ombai and Lombok Strait, whereas that for LICOM2.0 is mainly through the Timor Passage. The variability of the vertical structure of velocities and the volume transport are also investigated. LICOM2.0 overestimates the magnitude of the upper-layer currents and the amplitude of the variation. We also found that the largest correlation coefficient occurs in the shallowest strait, the Lombok, whereas the lowest occurs in the Timor Passage, especially in the upper layer. The latter may be caused by the unrealistic transport through the Torres Strait in LICOM2.0.

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Section: Model Description and Experimentsmentioning

confidence: 99%

Indonesian Throughflow in an eddy-resolving ocean model

et al. 2013

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“…For the integrations considered here, the atmosphere model (CAM3) (Collins et al 2006b) is run at T85 resolution (approximately 1.4 degrees) with 26 vertical levels. The ocean model (Smith and Gent 2004) includes an isopycnal transport parameterization (Gent and McWilliams 1990) and a surface boundary layer formulation following Large et al (1994). The dynamic-thermodynamic sea ice model (Briegleb et al 2004;Holland et al 2006b) uses the elasticviscous-plastic rheology (Hunke and Dukowicz 1997), a sub-gridscale ice thickness distribution (Thorndike et al 1975;Lipscomb 2001) and the thermodynamics of Bitz and Lipscomb (1999).…”

Section: Climate Model Integrationsmentioning

confidence: 99%

Inherent sea ice predictability in the rapidly changing Arctic environment of the Community Climate System Model, version 3

2010

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Seasonal predictions of Arctic sea ice have typically been based on statistical regression models or on results from ensemble ice model forecasts driven by historical atmospheric forcing. However, in the rapidly changing Arctic environment, the predictability characteristics of summer ice cover could undergo important transformations. Here global coupled climate model simulations are used to assess the inherent predictability of Arctic sea ice conditions on seasonal to interannual timescales within the Community Climate System Model, version 3. The role of preconditioning of the ice cover versus intrinsic variations in determining sea ice conditions is examined using ensemble experiments initialized in January with identical ice-ocean-terrestrial conditions. Assessing the divergence among the ensemble members reveals that sea ice area exhibits potential predictability during the first summer and for winter conditions after a year. The ice area exhibits little potential predictability during the spring transition season. Comparing experiments initialized with different mean ice conditions indicates that ice area in a thicker sea ice regime generally exhibits higher potential predictability for a longer period of time. In a thinner sea ice regime, winter ice conditions provide little ice area predictive capability after approximately 1 year. In all regimes, ice thickness has high potential predictability for at least 2 years.

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“…Nonlinear momentum terms are solved using a vector invariant formulation (Adcroft et al 2004) with viscous dissipation following Leith (1969), but modified to dissipate divergence as well as vorticity. In our model configuration, the parameterization of geostrophic eddies using the method of Gent-McWilliams (GM)/Redi (Redi 1982;Gent and McWilliams 1990) was disabled. Furthermore, there is no overflow parameterization.…”

Section: A Model Descriptionmentioning

confidence: 99%

Simulated Response of the Arctic Freshwater Budget to Extreme NAO Wind Forcing

et al. 2009

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The authors investigate the response of the Arctic Ocean freshwater budget to changes in the North Atlantic Oscillation (NAO) using a regional-ocean configuration of the Massachusetts Institute of Technology GCM (MITgcm) and carry out several different 10-yr and 30-yr integrations. At 1 / 6 8 (;18 km) resolution the model resolves the major Arctic transport pathways, including Bering Strait and the Canadian Archipelago. Two main calculations are performed by repeating the wind fields of two contrasting NAO years in each run for the extreme negative and positive NAO phases of 1969 and 1989, respectively. These calculations are compared both with a control run and the compiled observationally based freshwater budget estimate of Serreze et al.The results show a clear response in the Arctic freshwater budget to NAO forcing, that is, repeat NAO negative wind forcing results in virtually all freshwater being retained in the Arctic, with the bulk of the freshwater content being pooled in the Beaufort gyre. In contrast, repeat NAO positive forcing accelerates the export of freshwater out of the Arctic to the North Atlantic, primarily via Fram Strait (;900 km 3 yr 21 ) and the Canadian Archipelago (;500 km 3 yr 21 ), with a total loss in freshwater storage of ;13 000 km 3 (15%) after 10 yr. The large increase in freshwater export through the Canadian Archipelago highlights the important role that this gateway plays in redistributing the freshwater of the Arctic to subpolar seas, by providing a direct pathway from the Arctic basin to the Labrador Sea, Gulf Stream system, and Atlantic Ocean.The authors discuss the sensitivity of the Arctic Ocean to long-term fixed extreme NAO states and show that the freshwater content of the Arctic is able to be restored to initial values from a depleted freshwater state after ;20 yr.

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Isopycnal Mixing in Ocean Circulation Models

Cited by 2,907 publications

References 10 publications

Indonesian Throughflow in an eddy-resolving ocean model

Indonesian Throughflow in an eddy-resolving ocean model

Inherent sea ice predictability in the rapidly changing Arctic environment of the Community Climate System Model, version 3

Simulated Response of the Arctic Freshwater Budget to Extreme NAO Wind Forcing

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