On the Utility and Disutility of JEBAR*

Kamenkovich, Vladimir M.; Krupitsky, Alexander

doi:10.1175/1520-0485(1998)028<0519:otuado>2.0.co;2

Cited by 40 publications

(31 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We should mention that some of the relations in this section have previously been discussed in Olbers and Wübber (1991), Olbers et al (1992), Mertz and Wright (1992) and Cane et al (1998).…”

Section: Discussionmentioning

confidence: 54%

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

Section: Discussionmentioning

confidence: 54%

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

2006

View full text Add to dashboard Cite

show abstract

“…This is of the order of the interpentadal changes estimated from hydrographic observations by Sato and Rossby (1995), but substantially smaller than the 30 Sv estimated by Greatbach et al (1991). However, doubts have been raised on the reliability of the latter calculation (Cane et al 1998).…”

Section: Summary and Discussionmentioning

confidence: 77%

“…Note, however, that serious doubts have been raised on the reliability of such a calculation with limited data (Cane et al 1998), which was furthermore based on a simplifying assumption (linearity, no mixing or Reynolds stresses) that may not apply to the GS region. Using a large number of hydrographic sections, Sato and Rossby (1995) estimated that the decrease in the baroclinic transport was 6 Sv for the same period of time, and they found that their best sample pentads were within 4 Sv of each other.…”

mentioning

confidence: 99%

Gulf Stream Variability in Five Oceanic General Circulation Models

Coëtlogon¹,

Frankignoul

Bentsen³

et al. 2006

Journal of Physical Oceanography

View full text Add to dashboard Cite

Five non-eddy-resolving oceanic general circulation models driven by atmospheric fluxes derived from the NCEP reanalysis are used to investigate the link between the Gulf Stream (GS) variability, the atmospheric circulation, and the Atlantic meridional overturning circulation (AMOC). Despite the limited model resolution, the temperature at the 200-m depth along the mean GS axis behaves similarly in most models to that observed, and it is also well correlated with the North Atlantic Oscillation (NAO), indicating that a northward (southward) GS shift lags a positive (negative) NAO phase by 0-2 yr. The northward shift is accompanied by an increase in the GS transport, and conversely the southward shift with a decrease in the GS transport. Two dominant time scales appear in the response of the GS transport to the NAO forcing: a fast time scale (less than 1 month) for the barotropic component, and a slower one (about 2 yr) for the baroclinic component. In addition, the two components are weakly coupled. The GS response seems broadly consistent with a linear adjustment to the changes in the wind stress curl, and evidence for baroclinic Rossby wave propagation is found in the southern part of the subtropical gyre. However, the GS shifts are also affected by basin-scale changes in the oceanic conditions, and they are well correlated in most models with the changes in the AMOC. A larger AMOC is found when the GS is stronger and displaced northward, and a higher correlation is found when the observed changes of the GS position are used in the comparison. The relation between the GS and the AMOC could be explained by the inherent coupling between the thermohaline and the wind-driven circulation, or by the NAO variability driving them on similar time scales in the models.

show abstract

“…In general, both the wind and slope torque terms represent sources of vorticity, while the speed torque and frictional dissipation terms represent sinks of vorticity. As neither stratification nor bottom pressure observations were available during the study period, the effects of barotropic and baroclinic pressure gradients (e.g., Huthnance 1984;Cane et al 1998) are neglected here.…”

Section: Vorticity Equationmentioning

confidence: 99%

The Occurrence, Drivers, and Implications of Submesoscale Eddies on the Martha’s Vineyard Inner Shelf

Kirincich

2016

Journal of Physical Oceanography

View full text Add to dashboard Cite

The occurrence, drivers, and implications of small-scale O(2-5) km diameter coherent vortices, referred to as submesoscale eddies, over the inner shelf south of Martha's Vineyard, Massachusetts, are examined using highfrequency (HF), radar-based, high-resolution (400 m) observations of surface currents. Within the 300 km 2 study area, eddies occurred at rates of 1 and 4 day 21 in winter and summer, respectively. Most were less than 5 h in duration, smaller than 4 km in diameter, and rotated less than once over their lifespan; 60% of the eddies formed along the eastern edge of study area, adjacent to Wasque Shoal, and moved westward into the interior, often with relative vorticity greater than f. Eddy generation was linked to vortex stretching on the ebb and flood tide as well as the interaction of the spatially variable tide and the wind-driven currents; however, these features had complex patterns of surface divergence and stretching. Eddies located away from Wasque Shoal were related to the movement of wind-driven surface currents, as wind direction controlled where eddies formed as well as density effects. Using an analysis of particles advected within the radar-based surface currents, the observed eddies were found to be generally leaky, losing 60%-80% of particles over their lifespan, but still more retentive than the background flow. As a result, the combined translation and rotational effects of the observed eddies were an important source of lateral exchange for surface waters over the inner shelf.

show abstract

On the Utility and Disutility of JEBAR*

Cited by 40 publications

References 11 publications

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

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

Gulf Stream Variability in Five Oceanic General Circulation Models

The Occurrence, Drivers, and Implications of Submesoscale Eddies on the Martha’s Vineyard Inner Shelf

Contact Info

Product

Resources

About