Accelerating the Convergence to Equilibrium of Ocean-Climate Models

Bryan, Kirk

doi:10.1175/1520-0485(1984)014<0666:atcteo>2.0.co;2

Cited by 293 publications

(163 citation statements)

References 0 publications

Supporting

Mentioning

162

Contrasting

Order By: Relevance

“…Because the momentum, surface and abyssal tracers possess distinct evolving time scales, the convergence to equilibrium can be sped up by taking a larger time step for a more slowly evolving process [Bryan, 1984]. In this stage, the surface tracer time step is 9 hours.…”

Section: Accelerated Integrationmentioning

confidence: 99%

An assessment of the Geophysical Fluid Dynamics Laboratory ocean model with coarse resolution: Annual‐mean climatology

Jiang¹,

Stone²,

Malanotte‐Rizzoli³

1999

J. Geophys. Res.

View full text Add to dashboard Cite

OBAs. However, there is only a slight further improvement in the poleward heat transport in the Northern Hemisphere, which now has a peak value of 1.6 PW, still about 0.5 PW less than in OBAs. The sea surface temperature errors in E3 are consistent with the conclusion that the heat transport in the Northern Hemisphere is still being underestimated. All the experiments show strong systematic biases in the salinity field.

show abstract

Section: Accelerated Integrationmentioning

confidence: 99%

An assessment of the Geophysical Fluid Dynamics Laboratory ocean model with coarse resolution: Annual‐mean climatology

Jiang¹,

Stone²,

Malanotte‐Rizzoli³

1999

J. Geophys. Res.

View full text Add to dashboard Cite

show abstract

“…These waves may have been excited in spite of strong friction by the asynchronous time stepping that was used to accelerate the model integration up to year 18. Using a longer time step on temperature and salinity than on the momentum variables can lead to spurious baroclinic instabilities [Bryan, 1984].…”

Section: Circulationmentioning

confidence: 99%

Ocean general circulation from a global eddy‐resolving model

Semtner¹,

Chervin²

1992

J. Geophys. Res.

462

186

View full text Add to dashboard Cite

A concerted effort has been made to simulate the global ocean circulation with resolved eddies, using a highly optimized model on the best available supercomputer. An earlier 20-year spin-up has been extended for 12.5 additional years: the first 2.5 with continued annual mean forcing and the final 10.0 with climatological monthly forcing. Model output archived at 3-day intervals has been analyzed into mean fields, standard deviations, products, and covariances on monthly, annual, and multiyear time scales. The multiyear results are examined here in order to give insight into the general circulation of the world ocean. The three-dimensional How fields of the model are quite realistic, even though resolution of eddies in high latitudes is marginal with a 0.5°, 20-level grid. The use of seasonal forcing improves the simulation, especially in the tropics and high northern latitudes. Mid-latitude gyre circulations, western boundary currents, zonal equatorial Hows, and the Antarctic Circumpolar Current (ACC) all show mean and eddy characteristics similar to those observed. There is also some indication of eddy intensification of the mean How of the ACC and of separated boundary jets. A global thermohaline circulation of North Atlantic Deep Water is identified in deep western boundary currents connected by the ACC. This deep circulation rises mainly in the equatorial Pacific. Several zonal jets are an integral part of this circulation near the equator. The deep How rises toward the surface in a series of switchbacks. Much of the thermohaline return How then follows an eddy-rich warm-water route through the Indonesian archipelago and around the southern tip of Africa. However, some intermediate level portions of the thermohaline circulation return south into the ACC and follow a cold water route through the Drake Passage. The representation of a global "conveyor belt" circulation with narrow and relatively high-speed currents along most of its path may be the most important result of this modeling study. Statistics of scalar fields such as transport stream function and surface height are exhibited, as are time series and frequency spectra of certain variables at selected points. These provide a baseline for comparison both with observations and with other model studies at higher resolution. Mean and eddy characteristics of the near-surface temperature and salinity fields are discussed, and surface forcing fields are examined. In particular, combined thermal and hydrological forcing effects are found to drive a conveyor belt circulation between the tropical Pacific and the high-latitude North Atlantic. The effect of weak restoring terms to observed temperature and salinity at great depth and in polar latitudes is found mainly to augment the model's convective processes, which are poorly resolved with 0.5° grid spacing. However, the deep restoring terms are insignificant in both the tropics and the mid-latitudes. The geographical distributions of eddy heat and salt transport are discussed. The eddies transport heat and sa...

show abstract

“…These properties are undesirable for studies of changes in the thermohaline circulation where integration times of at least a few thousand years are desired. To decrease the number of time steps, 'false' transient methods, which allow for larger time steps in the deep ocean, are very common [6]. However, apart from the fact that this may distort the transient flow, the time steps are still orders of magnitude smaller than the desired integration time.…”

Section: Introductionmentioning

confidence: 99%