The Mean Summertime Circulation along Australia's Southern Shelves: A Numerical Study

Middleton, John; Platov, Guennadi

doi:10.1175/1520-0485(2003)033<2270:tmscaa>2.0.co;2

Cited by 54 publications

(84 citation statements)

References 16 publications

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“…Middleton and Cirano (2002) used an idealized numerical model to examine the Flinders Current, with simple geometry and topography, and did not include horizontal variations in density. The mean summertime shelf circulation of Australia's southern shelves was examined by Middleton and Platov (2003). The model domain extended from $1201E across to the western coast of Tasmania and included western Bass Strait.…”

Section: Modeling Backgroundmentioning

confidence: 96%

“…An anticyclonic gyre exists in the Great Australian Bight as this coastal current continues eastward along the shelf break while inshore of it, a westward current flows near the shore (Middleton and Platov, 2003). This westward current along the shore causes upwelling along the coast of the eastern Bight and advects cold water westward in the Bight (Herzfeld and Tomczak, 1997).…”

Section: Observational Backgroundmentioning

confidence: 99%

“…This westward current along the shore causes upwelling along the coast of the eastern Bight and advects cold water westward in the Bight (Herzfeld and Tomczak, 1997). This anticyclonic circulation also causes a local high in the sea level between 1201E and 1301E (Middleton and Platov, 2003). This circulation appears to be largely unaffected by surface heat fluxes and fresh water input (Middleton and Platov, 2003).…”

Section: Observational Backgroundmentioning

confidence: 99%

“…This anticyclonic circulation also causes a local high in the sea level between 1201E and 1301E (Middleton and Platov, 2003). This circulation appears to be largely unaffected by surface heat fluxes and fresh water input (Middleton and Platov, 2003).…”

Section: Observational Backgroundmentioning

confidence: 99%

“…This is one of very few areas anywhere along the southern Australian coastline where upwelling is regularly found at the surface. Upwelling has even been observed when winds are not upwelling favorable (Middleton and Platov, 2003). Ridgway and Condie (2004) have suggested a standard naming convention for the large-scale current system of the southern coast (which will be used in this study) based on differences in geography, forcing mechanisms, and water masses.…”

Section: Observational Backgroundmentioning

confidence: 99%

See 4 more Smart Citations

Process-oriented modeling studies of the 5500-km-long boundary flow off western and southern Australia

Batteen

Miller

2009

Continental Shelf Research

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Section: Modeling Backgroundmentioning

confidence: 96%

Section: Observational Backgroundmentioning

confidence: 99%

Section: Observational Backgroundmentioning

confidence: 99%

Section: Observational Backgroundmentioning

confidence: 99%

Section: Observational Backgroundmentioning

confidence: 99%

See 3 more Smart Citations

Process-oriented modeling studies of the 5500-km-long boundary flow off western and southern Australia

Batteen

Miller

2009

Continental Shelf Research

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Cross-shelf seawater exchange controls the distribution of temperature, salinity, and neritic carbonate sediments in the Great Australian Bight

Middleton

James

et al. 2014

J. Geophys. Res. Oceans

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The seasonally averaged wind stress of the Great Australian Bight (GAB) during the austral winter is directed to the east along the shelf and results in downwelling that extends to depths of 250 m. This downwelling is enhanced in the eastern GAB through the outflow of cold saline water formed in the broad shallow regions of the GAB and gulfs. During the austral summer, the averaged wind stress field of the GAB is anticyclonic with upwelling favorable winds along much of the coastline. In general however, significant slope upwelling is only observed in the eastern and western GAB where the shelf is narrow. Upwelling there provides nutrients to support the planktic and pelagic communities and the observed distribution of benthic invertebrate communities that lead to the formation of neritic carbonate sediments. At the shelf break of the central GAB where the shelf is very wide, the observed cross‐shelf distributions of temperature, salinity, and sediments indicate that downwelling occurs year round. The implied lack of nutrients is argued to explain the smaller communities of invertebrates found at the shelf edge (100–250 m) in these areas. A previous numerical study is cited to show that summer downwelling very likely results from a convergence of the deep ocean and poleward Sverdrup transports. The unique aspect of this integrated oceanographic‐sedimentological investigation is to tie outcomes of that numerical study with extant observations and benthic habitat to provide a consistent picture of how cross‐shelf exchange regulates water properties and benthos in the GAB.

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Nitrate Sources, Supply, and Phytoplankton Growth in the Great Australian Bight: An Eulerian‐Lagrangian Modeling Approach

et al. 2018

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The Great Australian Bight (GAB), a coastal sea bordered by the Pacific, Southern, and Indian Oceans, sustains one of the largest fisheries in Australia but the geographical origin of nutrients that maintain its productivity is not fully known. We use 12 years of modeled data from a coupled hydrodynamic and biogeochemical model and an Eulerian‐Lagrangian approach to quantify nitrate supply to the GAB and the region between the GAB and the Subantarctic Australian Front (GAB‐SAFn), identify phytoplankton growth within the GAB, and ascertain the source of nitrate that fuels it. We find that nitrate concentrations have a decorrelation timescale of ∼60 days; since most of the water from surrounding oceans takes longer than 60 days to reach the GAB, 23% and 75% of nitrate used by phytoplankton to grow are sourced within the GAB and from the GAB‐SAFn, respectively. Thus, most of the nitrate is recycled locally. Although nitrate concentrations and fluxes into the GAB are greater below 100 m than above, 79% of the nitrate fueling phytoplankton growth is sourced from above 100 m. Our findings suggest that topographical uplift and stratification erosion are key mechanisms delivering nutrients from below the nutricline into the euphotic zone and triggering large phytoplankton growth. We find annual and semiannual periodicities in phytoplankton growth, peaking in the austral spring and autumn when the mixed layer deepens leading to a subsurface maximum of phytoplankton growth. This study highlights the importance of examining phytoplankton growth at depth and the utility of Lagrangian approaches.

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The Mean Summertime Circulation along Australia's Southern Shelves: A Numerical Study

Cited by 54 publications

References 16 publications

Process-oriented modeling studies of the 5500-km-long boundary flow off western and southern Australia

Process-oriented modeling studies of the 5500-km-long boundary flow off western and southern Australia

Cross-shelf seawater exchange controls the distribution of temperature, salinity, and neritic carbonate sediments in the Great Australian Bight

Nitrate Sources, Supply, and Phytoplankton Growth in the Great Australian Bight: An Eulerian‐Lagrangian Modeling Approach

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