Penetration of Buoyant Coastal Discharge onto the Continental Shelf: A Numerical Model Experiment

Garvine, Richard W.

doi:10.1175/1520-0485(1999)029<1892:pobcdo>2.0.co;2

Cited by 148 publications

(172 citation statements)

References 29 publications

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“…Second, some of the source transport may not be carried by the gravity current, and instead is diverted into a growing recirculation zone near the source (e.g. Garvine 1999). This point is perhaps even more important in application of the results to the coastal ocean where studies have shown that a significant fraction of the source transport (e.g.…”

Section: Evaluation Of the Scalingmentioning

confidence: 99%

“…small bottom slopes. Garvine (1999) used a numerical model to investigate how far along the coast a gravity current would extend before it was completely dispersed by mixing with the ambient shelf water. Chapman & Lentz (1994) and Yankovsky & Chapman (1997) used numerical models to study the dynamics of slope-controlled gravity currents.…”

Section: Surface Flow Fieldsmentioning

confidence: 99%

“…The numerical model runs by Chapman & Lentz (1994) (12 model runs) and Yankovsky & Chapman (1997) (nine model runs) focused on slope-controlled gravity currents for which c w /c α ranged from 1 to 13. Garvine (1999) varied Q, ∆ρ, α, source widths and latitude (f). The gravity currents only penetrate a finite distance along the coast because of mixing.…”

Section: Surface Flow Fieldsmentioning

confidence: 99%

“…However, the relevance of these studies to the typical geophysical applications where the buoyant gravity current propagates along a sloping bottom is unclear. Previous laboratory (Whitehead & Chapman 1986) and numerical modelling studies (Chao 1988;Chapman & Lentz 1994;Kourafalou et al 1996;Yankovsky & Chapman 1997;Xing & Davies 1999;Garvine 1999) suggest a sloping bottom has a profound influence on the characteristics and dynamics of buoyant gravity currents (hereafter referred to as simply gravity currents).…”

Section: Introductionmentioning

confidence: 99%

“…Whitehead & Chapman (1986) found in a laboratory study that a gravity current on a sloping bottom was more stable, wider, and the nose propagated more slowly than a gravity current along a wall, but they did not offer a dynamical explanation for their results. Garvine (1999) found empirically from numerical model results that gravity current widths over a slope did not scale simply with the deformation radius based on the source conditions, but instead also depended on the bottom slope. A recent laboratory study by Avicola & Huq (2002) also demonstrates the importance of bottom slope to the buoyant gravity current response.…”

Section: Introductionmentioning

confidence: 99%

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Buoyant gravity currents along a sloping bottom in a rotating fluid

2002

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The dynamics of buoyant gravity currents in a rotating reference frame is a classical problem relevant to geophysical applications such as river water entering the ocean. However, existing scaling theories are limited to currents propagating along a vertical wall, a situation almost never realized in the ocean. A scaling theory is proposed for the structure (width and depth), nose speed and flow field characteristics of buoyant gravity currents over a sloping bottom as functions of the gravity current transport Q, density anomaly g′, Coriolis frequency f, and bottom slope α. The nose propagation speed is cp ∼ cw/ (1 + cw/cα) and the width of the buoyant gravity current is Wp ∼ cw/ f(1 + cw/cα), where cw = (2Qg′ f)1/4 is the nose propagation speed in the vertical wall limit (steep bottom slope) and cα = αg/f is the nose propagation speed in the slope-controlled limit (small bottom slope). The key non-dimensional parameter is cw/cα, which indicates whether the bottom slope is steep enough to be considered a vertical wall (cw/cα → 0) or approaches the slope-controlled limit (cw/cα → ∞). The scaling theory compares well against a new set of laboratory experiments which span steep to gentle bottom slopes (cw/cα = 0.11–13.1). Additionally, previous laboratory and numerical model results are reanalysed and shown to support the proposed scaling theory.

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Section: Evaluation Of the Scalingmentioning

confidence: 99%

Section: Surface Flow Fieldsmentioning

confidence: 99%

Section: Surface Flow Fieldsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Buoyant gravity currents along a sloping bottom in a rotating fluid

2002

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Wind forcing controls on river plume spreading on a tropical continental shelf

2015

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The Berau Continental Shelf is located close to the Equator in the Indonesian Archipelago, hosting a complex of coral reefs along its oceanic edge. The Berau coral reefs have a very high biodiversity, but the area is under serious risk due to river-derived nutrients and sediments. The region is characterized by weak winds, moderate tides, and almost absent Coriolis forcing. Existing knowledge about river plume behavior in tropical environments is limited. The aim of this paper is to investigate the influence of the subtle physical forcing on the dynamics of the Berau river plume. A three-dimensional model (ECOMSED) was calibrated with observational data. The model was forced by freshwater input from the Berau river distributaries, tides at the open boundaries, and measured hourly wind. The model reproduces the freshwater dynamics on the shelf adequately and highlights that the river plume spreads symmetrically for river forcing only. Tides cause vertical mixing and suppress the cross-shelf spreading of the river plume. However, the spreading of the river plume over the shelf is mainly controlled by the weak monsoonal winds, resulting in a seasonal development. During the Southeast Monsoon, the southerly winds push the plume northeastward and cause a stratified water column in the northern part of the continental shelf. Northerly winds during the Northwest Monsoon disperse the plume to the south, promoting a vertically well-mixed water column. The results can be used to predict the possible impact of land-use changes in the steadily developing Berau region on coral reef health.

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Observed and modeled drifters at a tidal inlet

Spydell

Feddersen

Olabarrieta

et al. 2015

J. Geophys. Res. Oceans

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Material transport and dispersion near the mouth of a tidal inlet (New River Inlet, NC) are investigated using GPS-tracked drifters and numerical models. For ebb tide releases, velocities are largest (>1 m s 21 )in two approximately 30 m wide channels that bisect the 1-3 m deep ebb shoal. In the channels, drifter and subsurface current meter velocities are similar, consistent with strong vertical mixing and 2-D hydrodynamics. Drifters were preferentially entrained in the channelized jets where drifter cluster lateral spreading rates l in were small (l in % 0:5 m 2 s 21 ). At the seaward edge of the ebb shoal, jet velocities decrease linearly with distance (to 0:2 m s 21 , about 1 km from shore), and cluster spreading rates are larger with l out % 3 m 2 s 21 .Although the models COAWST and NearCom generally reproduce the observed trajectory directions, certain observed drifter properties are poorly modeled. For example, modeled mean drifter velocities are smaller than observed, and upon exiting the inlet, observed drifters turn north more than modeled drifters. The model simulations do reproduce qualitatively the spreading rates observed in the inner inlet, the flow deceleration, and the increase in l out observed in the outer inlet. However, model spreading rates increase only to l out < 1 m 2 s 21 . Smaller modeled than observed l out may result from using unstratified models. Noncoincident (in space) observations show evidence of a buoyant plume (Dq51 kg m 23 ) in the outer inlet, likely affecting drifter lateral spreading. Generally, drifter-based model performance is good within the inlet channels where tidal currents are strongest, whereas model-data differences are significant farther offshore.

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Penetration of Buoyant Coastal Discharge onto the Continental Shelf: A Numerical Model Experiment

Cited by 148 publications

References 29 publications

Buoyant gravity currents along a sloping bottom in a rotating fluid

Buoyant gravity currents along a sloping bottom in a rotating fluid

Wind forcing controls on river plume spreading on a tropical continental shelf

Observed and modeled drifters at a tidal inlet

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