Perturbations to the Gulf Stream by Atlantis II Seamount

Vastano, Andrew C.; Warren, Bruce A.

doi:10.1016/s0011-7471(76)80014-9

Cited by 16 publications

(20 citation statements)

References 16 publications

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“…Probably the ®rst observation of uplifted isopycnals above a seamount was reported by Defant (1940) from the Altair Seamount in the North Atlantic. More recent studies con®rm the ubiquitous existence of such density anomalies and point out that there must be a corresponding anticyclonic¯ow about them (Meincke 1971;Vastano and Warren 1976;Genin and Boehlert 1985;Roden 1987;Genin et al 1989;Bersch et al 1992). This closed circulation is referred to as a Taylor cap, the generalization of the well-known Taylor column in a strati®ed uid.…”

Section: Observationsmentioning

confidence: 99%

The effect of flow at Maud Rise on the sea-ice cover numerical experiments

Beckmann¹,

Timmermann²,

Pereira³

et al. 2001

Ocean Dynamics

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The role of seamounts in the formation and evolution of sea ice is investigated in a series of numerical experiments with a coupled sea ice±ocean model. Bottom topography, strati®cation and forcing are con®gured for the Maud Rise region in the Weddell Sea. The speci®c¯ow regime that develops at the seamount as the combined response to steady and tidal forcing consists of free and trapped waves and a vortex cap, which is caused by mean¯ow and tidal¯ow recti®cation. The enhanced variability through tidal motion in particular modi®es the mixed layer above the seamount enough to delay and reduce sea-ice formation throughout the winter. The induced sea-ice anomaly spreads and moves westward and a ects an area of several 100 000 km 2 . Process studies reveal the complex interaction between wind, steady and periodic ocean currents: all three are required in the process of generation of the sea ice and mixed layer anomalies (mainly through tidal¯ow), their detachment from the topography (caused by steady oceanic¯ow) and the westward translation of the sea-ice anomaly (driven by the timemean wind).

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Section: Observationsmentioning

confidence: 99%

The effect of flow at Maud Rise on the sea-ice cover numerical experiments

Beckmann¹,

Timmermann²,

Pereira³

et al. 2001

Ocean Dynamics

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“…Some of the first evidence of the local effect on mesoscale flow over a seamount was given by Vastano and Warren (1976). In this study they observed flow over the Atlantis II seamount, which rises to 1645 m from the surface of the ocean, over 3000 m from the bottom.…”

Section: Observations Of Flow Over Isolated Topography In the Oceanmentioning

confidence: 67%

Flow over finite isolated topography

Thompson¹

1990

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One and two layer models are used to study flow over axisymmetric isolated topography. Inviscid or nearly inviscid flow in which non-linear effects have order one importance is considered, and both the effects of P and finite topography are included.A one-layer quasi-geostrophic model is used to find the shape of Taylor columns on both the f-plane and the #-plane in the inviscid limit of the frictional problem.In this limit, the boundary of the Taylor column is a streamline, and the velocity in both directions vanishes on the boundary. The fluid within the Taylor column is stagnant, corresponding to the solution that Ingersoll (1969) found for flow over a right circular cylinder on the f-plane. In this case, the Taylor column is circular. An iterative boundary integral technique is used to find the solutions for flow over a cone on the f-plane. In this case the Taylor column has a tear drop shape. Solutions are also found for flow on the #-plane over a cylinder, and the Taylor column is approximately elliptical for westward flow with the major axis in the x direction, while it is slightly elongated in the y direction for eastward flow. The stagnation point of the Taylor column is located on the edge of the topography for all the solutions found. It was not possible to find solutions for smooth topographic shapes. Steady solutions for flow over a right circular cylinder of finite height are studied when the quasi-geostrophic approximation no longer applies. The solution consists of two parts, one which is similar to the quasi-geostrophic solution and is driven by the potential vorticity anomaly over the topography and the other which is similar to the solution of potential flow around an cylinder and is driven by the matching conditions on the edge of the topography. When the effect of # is large, the transport over the topography is enhanced as the streamlines follow lines of constant background potential vorticity. For eastward flow, the Rossby wave drag can be much larger than predicted from quasi-geostrophic theory.A two-layer model over finite topography using the quasi-geostrophic approximation is developed. The topography is a right circular cylinder which goes all of the way through the lower layer and an order Rossby number amount into the upper layer, so that the quasi-geostrophic approximation can be applied consistently. This geometry allows description of flow in which an isopycnal intersects the topography. The model is valid for a different regime than existing models of steady flow over finite topography in a continuously stratified fluid in which the bottom boundary is an isopycnal surface. The solutions contain the two components that are found in the the barotropic model of flow over finite topography. The model breaks down when the interface goes above the topography which occurs more easily when the stratification is weak. Closed streamlines occur more readily over the topography when the stratification is weak, whereas in traditional quasi-geostrophic theory they occur more readily w...

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“…(1978] for additional sections through the eastern rings). A possible explanation is that as t he G ulf Stream passes over the New England Seamount C hain, it is split into filaments and made broader [Fuglister, 1963;Vastano and Warren, 1976). Rings which fo rm east of the seamount chain may reflect the Gulf Stream's character at the time of formation and therefore look different from the rings formed west of the seamount chain .…”

Section: Ringsmentioning

confidence: 99%