Wind and topographic effects on the Labrador Current at Carson Canyon

Kinsella, E.; Hay, Alex E.; Denner, Warren W.

doi:10.1029/jc092ic10p10853

Cited by 27 publications

(15 citation statements)

References 23 publications

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“…Upwelling over a very wide canyon was observed over Quinault Canyon (Hickey et al, 1986). A brief upwelling interlude over Carson Canyon, a canyon usually in a positive flow field, has been documented (Kinsella et al, 1987). A study over a canyon off the west coast of Africa shows the strong response within a canyon with a low Coriolis parameter (Shaffer, 1976).…”

Section: Observations Of Upwelling/downwelling In Canyonsmentioning

confidence: 99%

A review of the role of submarine canyons in deep-ocean exchange with the shelf

2009

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Abstract. Cross shelf-break exchange is limited by the tendency of geostrophic flow to follow bathymetric contours, not cross them. However, small scale topography, such as canyons, can reduce the local lengthscale of the flow and increase the local Rossby number. These higher Rossby numbers mean the flow is no longer purely geostrophic and significant cross-isobath flow can occur. This cross-isobath flow includes both upwelling and downwelling due to wind-driven shelf currents and the strong cascading flows of dense shelfwater into the ocean. Tidal currents usually run primarily parallel to the shelf-break topography. Canyons cut across these flows and thus are often regions of generation of strong baroclinic tides and internal waves. Canyons can also focus internal waves. Both processes lead to greatly elevated levels of mixing. Thus, through both advection and mixing processes, canyons can enhance Deep Ocean Shelf Exchange. Here we review the state of the science describing the dynamics of the flows and suggest further areas of research, particularly into quantifying fluxes of nutrients and carbon as well as heat and salt through canyons.

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Section: Observations Of Upwelling/downwelling In Canyonsmentioning

confidence: 99%

A review of the role of submarine canyons in deep-ocean exchange with the shelf

2009

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“…An eddy is evident around Carson canyon from current meter observations [ Kinsella et al , 1987, Figure 8].…”

Section: Scaling Applicationsmentioning

confidence: 99%

Dynamics of advection‐driven upwelling over a shelf break submarine canyon

Allen

Hickey

2010

J. Geophys. Res.

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[1] The response over a submarine canyon to a several day upwelling event can be separated into three phases: an initial transient response; a later, much longer, "steady" advection-driven response; and a final relaxation phase. For the advection-driven phase over realistically steep, deep, and narrow canyons with near-uniform flow and stratification at rim depth, we have derived scale estimates for four key quantities. Observations from 5 real-world canyon studies and 3 laboratory studies are used to validate the scaling and estimate the scalar constant for each scale. Based on 4 geometric parameters of the canyon, the background stratification, the Coriolis parameter, and the incoming current, we can estimate (1) the depth of upwelling in the canyon to within 15 m, (2) the deep vorticity to within 15%, and (3) the presence/absence of a rim depth eddy can be determined. Based on laboratory data, (4) the total upwelling flux can also be estimated. The scaling analysis shows the importance of a Rossby number based on the radius of curvature of isobaths at the upstream mouth of the canyon. This Rossby number determines the ability of the flow to cross the canyon isobaths and generate the pressure gradient that drives upwelling in the canyon. Other important scales are a Rossby number based on the length of the canyon which measures the ability of the flow to lift isopycnals and a Burger number based on the width of the canyon that determines the likelihood of an eddy at rim depth. Generally, long canyons with sharply turning upstream isobaths, strong incoming flow, small Coriolis parameter, and weak stratification have the strongest upwelling response.Citation: Allen, S. E., and B. M. Hickey (2010), Dynamics of advection-driven upwelling over a shelf break submarine canyon,

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“…The near surface flow (<100 m) is only weakly affected by the canyon [ Hickey , 1997; Allen et al , 2003]. Most upwelling processes in short canyons occur during upwelling favorable wind events which generate a geostrophic incident flow [ Kinsella et al , 1987; Hickey , 1997]. Allen [2000] showed that in a short canyon, higher‐order effects generate the flow inside the canyon and no upwelling occurs for strictly geostrophic flow.…”

Section: Introductionmentioning

confidence: 99%

Upwelling flow dynamics in long canyons at low Rossby number

Waterhouse¹,

Allen²,

Bowie³

2009

J. Geophys. Res.

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[1] Submarine canyons, topographic features incising the continental slope, vary in both shape and size. The dynamics of short canyons have been observed and described in the field, in the laboratory, and with numerical simulations. Flow within long canyons, such as Juan de Fuca canyon, located between Vancouver Island and Washington State in the Pacific Northwest, is less well understood. Physical models of both long and short canyons have been constructed to understand the upwelling dynamics in long canyons and how upwelling changes, as compared with the dynamics of short canyons, at low Rossby number. Stratification and rotation, both important parameters in determining the dynamics in canyons, can be controlled and scaled accordingly for replication of oceanic conditions. The physical model is spun up to an initial rotation rate, and the flow is forced by increasing the rotation rate over the equivalent of several days. Flow visualization is used to determine the strength and location of upwelling, the strength and mechanisms generating vorticity, as well as the differences between the flow within the long and short canyons. The pattern of upwelling between the two canyons is significantly different in the horizontal with upwelling occurring through the canyon head in the short canyon and upwelling occurring close to the mouth along the downstream rim in the long canyon. At high Rossby number, upwelling is similar in both the long and short canyon and is driven by advection. However, as Rossby number decreases, the flow in the long canyon is more strongly affected by the strong convergence of the isobaths near the canyon than by advection alone.

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Wind and topographic effects on the Labrador Current at Carson Canyon

Cited by 27 publications

References 23 publications

A review of the role of submarine canyons in deep-ocean exchange with the shelf

A review of the role of submarine canyons in deep-ocean exchange with the shelf

Dynamics of advection‐driven upwelling over a shelf break submarine canyon

Upwelling flow dynamics in long canyons at low Rossby number

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