Barotropic Response of the Labrador/Newfoundland Shelf to a Moving Storm

Tang, Choon Yik; Gui, Q.; DeTracey, Brendan

doi:10.1175/1520-0485(1998)028<1152:brotln>2.0.co;2

Cited by 26 publications

(36 citation statements)

References 18 publications

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“…This difference may be due to many factors including water depth, wind intensity, stratification and the effect of continental shelf waves. The continental shelf wave is a type of topographic planetary wave generated by storms that is trapped over the continental margin and propagates along the shelf break or coastline (Detracey et al, 1996;Tang, et al, 1998;Thiebaut and Vennell, 2010). The contribution of the shelf wave is mainly to the barotropic currents, which can significantly increase the velocity in the bottom layer.…”

Section: Extreme Current Speedsmentioning

confidence: 99%

Modelling Extreme Storm-Induced Currents over the Grand Banks

Tang

Prescott³

2011

Atmosphere-Ocean

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Extreme storm-induced currents over the Grand Banks are investigated using a three-dimensional (3-D) ocean circulation model forced by 22 storms selected from the past 50 years with return intervals ranging from 1 to 34 years. Wind data for the storms are historical atmospheric data. The modelled currents are compared with current meter measurements made during a storm in March 1983. The results indicate good agreement between the model and measurements. In the surface layer of the Grand Banks, the model extreme current speeds are approximately 80 cm s −1 over a large portion of the Grand Banks, and some areas have extreme current speeds higher than 120 cm s −1 . The highest extreme current speeds occur at St. Pierre Bank, where the speed reaches 140 cm s −1 . In the bottom layer, the region with high extreme current speeds is mainly in the periphery of the Grand Banks, with magnitudes over 40 cm s −1 . The results also show that the response of the water to storm forcing in the Grand Banks area varies from place to place because the mechanisms of current generation are different at different locations. . Dans la couche de fond, la région de grandes vitesses de courants extrêmes se situe principalement à la périphérie des Grands Bancs, avec des valeurs d'environ 40 cm s −1 . Les résultats montrent aussi que la réponse de l'eau au forçage par les tempêtes dans la région des Grands Bancs varie d'un endroit à l'autre parce que les mécanismes de production de courant sont différents pour des endroits différents.

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Section: Extreme Current Speedsmentioning

confidence: 99%

Modelling Extreme Storm-Induced Currents over the Grand Banks

Tang

Prescott³

2011

Atmosphere-Ocean

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“…We used a controllable wind and pressure field to simulate the effect of a moving storm. This approach has been taken by a number of investigators (O'Brien & Reid 1967, Chang & Anthes 1978, Price 1983, Tang et al 1998). Following O'Brien & Reid (1967 and Tang et al (1998), the horizontal distribution of air pressure changes exponentially from the center to the periphery of the storm:…”

Section: Model Equations and Model Setupmentioning

confidence: 99%

“…6 can be associated with the topographic waves excited by the storm. During and after the passage of the storm, a complex horizontal velocity field is developed over the shelf (Tang et al 1998). The velocity field is composed of permanent currents, direct windforced currents, topographic waves, low-frequency currents and trapped inertio-gravity waves.…”

Section: Horizontal Changesmentioning

confidence: 99%

“…The physical response of the ocean to moving storms of dissimilar intensity, size and translation speed has been investigated in several previous numerical studies (Chang & Anthes 1978, Price 1981, Tang et al 1998. Our objective in this subsection is to examine how the chlorophyll field responds to the changes in translation speed, size and intensity of a storm. )…”

Section: Sensitivity To Storm Parameters (Runs 2 To 7)mentioning

confidence: 99%

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Short-term changes in chlorophyll distribution in response to a moving storm: a modelling study

Wu¹,

Platt²,

Tang³

et al. 2007

Mar. Ecol. Prog. Ser.

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Using a 3-D ocean circulation model of the Labrador Sea, we investigated the immediate response, through vertical redistribution of the chlorophyll field, to a steadily moving storm. The model is forced by a prescribed wind and pressure field. The numerical experiments included a control run to analyze the horizontal and vertical structure of the chlorophyll field, and several sensitivity runs to investigate the response to changes in the storm parameters (translation speed, size and intensity) and the seasonal distribution of chlorophyll. The model results showed that after the passage of the storm, surface chlorophyll in the Labrador Sea is generally increased by vertical mixing. The largest increase occurs in autumn. In summer (control run), the surface chlorophyll concentration is 1 to 3 mg m -3 higher than the concentration before the storm in almost all the areas under the influence of the storm. In the shelf regions, however, the increase is very small. The changes in surface chlorophyll concentration are shown to be primarily controlled by the mixed-layer depth and the initial chlorophyll distribution. Nitrate brought from the deep reservoir to the mixed layer by entrainment was estimated from the model. For a typical storm in summer, 3.35 × 10 3 mol of new nitrate is added to the mixed layer for each km of storm track. Primary production rates following the introduction of new nitrate will contribute to further change in surface chlorophyll, but on a longer time scale. KEY WORDS: Moving storm · Chlorophyll · Vertical distribution · 3-D modelResale or republication not permitted without written consent of the publisher

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“…Han (2000) reported the amplification of the diurnal tidal currents over the edge of the Grand Banks in his tidal modelling, but he used the longwave (over 1000 km in wavelength) first mode CSW to explain the phenomenon. In a non-tidal modelling example, Tang et al (1998) reported the occurrence of the eddy-like features over the Newfoundland shelf break with a wavelength of about 800 km excited by a passing storm and they attributed this to shelf waves with distinctive wavelength and frequency. Solutions of FUNDY5 (not reported here) at various subinertial periods for spatially-uniform wind stress or cross-shelf elevation gradients on the upstream (Labrador Shelf) boundary show amplified currents on the outer shelf and slope, particularly in the Grand Banks-Flemish Cap region.…”

Section: Summary and Discussionmentioning

confidence: 99%