On topographic pressure drag in a zonal channel

Krupitsky, Alexander

doi:10.1357/0022240943076740

Cited by 24 publications

(19 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Form stress has been recognized as the principal mechanism balancing the momentum input by the zonal mean winds in the Southern Ocean (Munk and Palmén 1951). Krupitsky and Cane (1994) and Wang and Huang (1995) corroborated the balance between topographic form drag and wind stress for the steady barotropic circulation in their circumpolar channel models. Their analyses focused on supercritical topography in which all contours of f /H are blocked.…”

Section: A Low-frequency Response: F ͻ 02 Cpdmentioning

confidence: 69%

Adjustment of the Southern Ocean to Wind Forcing on Synoptic Time Scales

Weijer

Gille

2005

Journal of Physical Oceanography

View full text Add to dashboard Cite

This study addresses the response of the Southern Ocean to high-frequency wind forcing, focusing on the impact of several barotropic modes on the circumpolar transport. A suite of experiments is performed with an unstratified model of the Southern Ocean, forced with a stochastic wind stress that contains a large range of frequencies with synoptic time scales. The Southern Ocean adjustment displays a different character for frequencies below and above 0.2 cpd. The low-frequency range is dominated by an "almost-free-mode" response in the region where contours of f /H are obstructed by only a few bathymetric features; the truly free mode only plays a minor role. Topographic form stress, rather than friction, is the dominant decay mechanism of the Southern Mode. It leads to a spindown time scale on the order of 3 days. For the high-frequency range, the circumpolar transport is dominated by the resonant excitation of oscillatory modes. The "active" response of the ocean leads to strong changes and even discontinuities in the phase relation between transport and wind stress.

show abstract

Section: A Low-frequency Response: F ͻ 02 Cpdmentioning

confidence: 69%

Adjustment of the Southern Ocean to Wind Forcing on Synoptic Time Scales

Weijer

Gille

2005

Journal of Physical Oceanography

View full text Add to dashboard Cite

show abstract

“…But inclusion of a realistic or idealized bottom relief did not provide circulations with more realistic transports since these were generally far too weak (e.g. Johnson and Hill 1975, Klinck 1991, Krupitsky and Cane 1994, Wang and Huang 1995, Krupitsky et al 1996. Analytical models with baroclinicity are rare.…”

Section: Introductionmentioning

confidence: 99%

Six circumpolar currents—on the forcing of the Antarctic Circumpolar Current by wind and mixing

2006

View full text Add to dashboard Cite

The transport of the Antarctic Circumpolar Current (ACC) is influenced by a variety of processes and parameters. A proper implementation of basin geometry, ocean topography and baroclinicity is known to be a fundamental requisite for a realistic simulation of the circulation and transport. Other, more subtle parameters are those of eddy-induced transports and diapycnal mixing of thermohaline tracers or buoyancy, either treated by eddy resolution or by a proper parameterization. Quite a number of realistic numerical simulations of the circulation in the Southern Ocean have recently been published. Many concepts on relations of the ACC transport to model parameters and forcing function are in the discussion, however, without much generality and little success.We present a series of numerical simulations of circumpolar flow with a simplified numerical model, ranging from flat-bottom wind-driven flow to baroclinic flow with realistic topography and wind and buoyancy forcing. Analysis of the balances of momentum, vorticity and baroclinic potential energy enables us to develop a new transport theory, which combines the most important mechanisms driving the circulation of the ACC and determining its zonal transport. The theory is based on the importance of the bottom vertical velocity in generating vorticity and shaping the baroclinic potential energy of the ACC. It explains the breaking of the f /h-constraint by baroclinicity and brings together in one equation the wind and buoyancy forcing of the current. The theory emphasizes the role of Ekman pumping and eddy diffusion of buoyancy to determine the transport. It also demonstrates that eddy viscosity effects are irrelevant in the barotropic vorticity balance and that friction arises via eddy diffusion of density. In this regime, the classical Stommel model of vorticity balance is revived where the bottom friction coefficient is replaced by K/λ 2 (with the GM coefficient K and the baroclinic Rossby radius λ) and a modified wind curl forcing appears.

show abstract

“…A great number of observational, theoretical and modelling studies have been made in order to study the ACC dynamics (Munk and Palmén 1951;Kamenkovich 1960;Baker 1982;Whitworth and Peterson 1985;Johnson and Bryden 1989;Morrow et al 1992;Marshall et al 1993;Krupitsky and Cane 1994;Killworth and Nanneh 1994;Wells and de Cuevas 1995;Ivchenko et al 1996;Best et al 1999;Gnanadesikan and Hallberg 2000;Gent et al 2001;Gille et al 2001;MacCready and Rhines 2001;Olbers and Ivchenko 2001;Tansley and Marshall 2001;Karsten et al 2002). We can single out several numerical models employed to represent the ACC: the Fine-Resolution Antarctic Model (FRAM) (FRAM group 1991), the Semtner-Chervin model Chervin 1988, 1992), the Parallel Ocean Program (POP) model (Maltrud et al 1998) and the Ocean Circulation and Climate Advanced Modelling (OCCAM) project (Webb et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Dynamical budgets of the Antarctic Circumpolar Current using ocean general-circulation models

Grezio

Wells

Ivchenko

et al. 2005

Q. J. R. Meteorol. Soc.

View full text Add to dashboard Cite

SUMMARYThree general-circulation models (FRAM, OCCAM and POP) are used to investigate the dynamics of the Antarctic Circumpolar Current (ACC) at the latitudes of the Drake Passage where the ACC is unbounded. In these general circulation models, bottom form stress balances the wind stress in the momentum budgets. In the vorticity budgets, the main balance is between wind curl and bottom pressure torque in FRAM, OCCAM and POP. Moreover, in the ACC belt all topographic features are regions of nonlinearity and bottom pressure torque variations, with the Drake Passage playing the largest role. Transient eddy Reynolds stresses (TERSs) play a different role in the three models. In the upper levels, TERSs accelerate the flow in the POP and FRAM models, but decelerate the flow in OCCAM. The behaviour of TERSs change throughout the whole water column in the ACC belt and Reynolds stresses have a dragging effect on the flow below the levels where the topography starts to obstruct the flow. The total volume transport in three models is very different. Additionally, the different spatial resolution, which results in a different level of eddy kinetic energy, has a significant influence on the transport.

show abstract

On topographic pressure drag in a zonal channel

Cited by 24 publications

References 16 publications

Adjustment of the Southern Ocean to Wind Forcing on Synoptic Time Scales

Adjustment of the Southern Ocean to Wind Forcing on Synoptic Time Scales

Six circumpolar currents—on the forcing of the Antarctic Circumpolar Current by wind and mixing

Dynamical budgets of the Antarctic Circumpolar Current using ocean general-circulation models

Contact Info

Product

Resources

About