Author: Michael Joseph Meuleners
Publisher:
ISBN:
Category : Eddies
Languages : en
Pages : 94
Book Description
[Truncated abstract] The study of eastern ocean boundary currents has been principally restricted to the Pacific and Atlantic ocean regions. The traditional view of the circulation near eastern ocean boundaries is that upwelling-favourable winds force surface waters offshore, leading to upwelling of cold, nutrient-rich subsurface water at the coast, the formation and offshore advection of a coastal front, and the generation of alongshore currents, generally having an equatorward surface flow and a poleward undercurrent. The eastern ocean boundary system of the southern Indian Ocean, off the west coast of Australia, is unique compared with these regions because a warm, poleward surface flow, known as the Leeuwin Current, dominates the dynamics over the continental shelf. Satellite imagery has shown the Leeuwin Current consists of a complex system of meanders, jet-like streams, and eddies, and has a seasonal and interannual variability. The oceanic circulation of the region between Carnarvon (latitude 25°S) and Jurien Bay (latitude 31°S) was examined using observational and remotely sensed data in conjunction with a detailed numerical modelling study. The model was validated using in situ ADCP and CTD data, and the horizontal eddy viscosity parameterization was tested against field observations. ... The resulting offshore meander grew laterally, shallowed, and closed to form an anticlockwise eddy to the original clockwise eddy’s south, forming a characteristic LC eddy pair (dipole). The model demonstrated the LC and Leeuwin Undercurrent (LUC) coupling played an important role in the onset of eddies at both sites. When an energy diagnostic scheme was used, the dominant instability process linked to the anticlockwise eddy’s development at site 1 was a mixed mode barotropic and baroclinic instability. The baroclinic instability’s source was the available potential energy stored within the mean lateral density gradient. The LC’s meandering southerly flow interacting with the LUC’s northerly subsurface flow generated the horizontal shear that sourced the barotropic instability. The dominant instability process at site 2 was baroclinic in origin. Possible links between the eddy field dynamics and the shelfslope region’s alongshore topographic variability were considered. The results of a suite of five model runs, differing only in the specification of bottom topography, were contrasted to investigate the effects. Except for the expected alongshore variability, delay in the onset of instabilities, varying growth rates, and some differences in the dominant wavebands’ mesoscale patterns, the overall impression was the response was similar.
A Numerical Study of the Mesoscale Eddy Dynamics of the Leeuwin Current System
Author: Michael Joseph Meuleners
Publisher:
ISBN:
Category : Eddies
Languages : en
Pages : 94
Book Description
[Truncated abstract] The study of eastern ocean boundary currents has been principally restricted to the Pacific and Atlantic ocean regions. The traditional view of the circulation near eastern ocean boundaries is that upwelling-favourable winds force surface waters offshore, leading to upwelling of cold, nutrient-rich subsurface water at the coast, the formation and offshore advection of a coastal front, and the generation of alongshore currents, generally having an equatorward surface flow and a poleward undercurrent. The eastern ocean boundary system of the southern Indian Ocean, off the west coast of Australia, is unique compared with these regions because a warm, poleward surface flow, known as the Leeuwin Current, dominates the dynamics over the continental shelf. Satellite imagery has shown the Leeuwin Current consists of a complex system of meanders, jet-like streams, and eddies, and has a seasonal and interannual variability. The oceanic circulation of the region between Carnarvon (latitude 25°S) and Jurien Bay (latitude 31°S) was examined using observational and remotely sensed data in conjunction with a detailed numerical modelling study. The model was validated using in situ ADCP and CTD data, and the horizontal eddy viscosity parameterization was tested against field observations. ... The resulting offshore meander grew laterally, shallowed, and closed to form an anticlockwise eddy to the original clockwise eddy’s south, forming a characteristic LC eddy pair (dipole). The model demonstrated the LC and Leeuwin Undercurrent (LUC) coupling played an important role in the onset of eddies at both sites. When an energy diagnostic scheme was used, the dominant instability process linked to the anticlockwise eddy’s development at site 1 was a mixed mode barotropic and baroclinic instability. The baroclinic instability’s source was the available potential energy stored within the mean lateral density gradient. The LC’s meandering southerly flow interacting with the LUC’s northerly subsurface flow generated the horizontal shear that sourced the barotropic instability. The dominant instability process at site 2 was baroclinic in origin. Possible links between the eddy field dynamics and the shelfslope region’s alongshore topographic variability were considered. The results of a suite of five model runs, differing only in the specification of bottom topography, were contrasted to investigate the effects. Except for the expected alongshore variability, delay in the onset of instabilities, varying growth rates, and some differences in the dominant wavebands’ mesoscale patterns, the overall impression was the response was similar.
Publisher:
ISBN:
Category : Eddies
Languages : en
Pages : 94
Book Description
[Truncated abstract] The study of eastern ocean boundary currents has been principally restricted to the Pacific and Atlantic ocean regions. The traditional view of the circulation near eastern ocean boundaries is that upwelling-favourable winds force surface waters offshore, leading to upwelling of cold, nutrient-rich subsurface water at the coast, the formation and offshore advection of a coastal front, and the generation of alongshore currents, generally having an equatorward surface flow and a poleward undercurrent. The eastern ocean boundary system of the southern Indian Ocean, off the west coast of Australia, is unique compared with these regions because a warm, poleward surface flow, known as the Leeuwin Current, dominates the dynamics over the continental shelf. Satellite imagery has shown the Leeuwin Current consists of a complex system of meanders, jet-like streams, and eddies, and has a seasonal and interannual variability. The oceanic circulation of the region between Carnarvon (latitude 25°S) and Jurien Bay (latitude 31°S) was examined using observational and remotely sensed data in conjunction with a detailed numerical modelling study. The model was validated using in situ ADCP and CTD data, and the horizontal eddy viscosity parameterization was tested against field observations. ... The resulting offshore meander grew laterally, shallowed, and closed to form an anticlockwise eddy to the original clockwise eddy’s south, forming a characteristic LC eddy pair (dipole). The model demonstrated the LC and Leeuwin Undercurrent (LUC) coupling played an important role in the onset of eddies at both sites. When an energy diagnostic scheme was used, the dominant instability process linked to the anticlockwise eddy’s development at site 1 was a mixed mode barotropic and baroclinic instability. The baroclinic instability’s source was the available potential energy stored within the mean lateral density gradient. The LC’s meandering southerly flow interacting with the LUC’s northerly subsurface flow generated the horizontal shear that sourced the barotropic instability. The dominant instability process at site 2 was baroclinic in origin. Possible links between the eddy field dynamics and the shelfslope region’s alongshore topographic variability were considered. The results of a suite of five model runs, differing only in the specification of bottom topography, were contrasted to investigate the effects. Except for the expected alongshore variability, delay in the onset of instabilities, varying growth rates, and some differences in the dominant wavebands’ mesoscale patterns, the overall impression was the response was similar.
A Numerical Study of the Forcing Mechanisms of the Leeuwin Current System
Author: Richard A. Kennedy, Jr.
Publisher:
ISBN: 9781423507369
Category :
Languages : en
Pages : 117
Book Description
To investigate the role of wind forcing, bottom topography and thermohaline gradients in the Leeuwin Current System (LCS) , several experiments are conducted with a sigma coordinate primitive equation model on a beta- plane. Results show that the LCS is an anomalous eastern boundary current (EBC) that generates a coastal poleward current, an equatorward undercurrent, and highly energetic mesoscale features such as meanders and eddies. Thermohaline gradient effects were shown to be the primary mechanism in the generation of a poleward (equatorward) current (undercurrent) , eddies and meanders in the LCS. Inshore of the poleward surface flow, next to the coast, wind forcing plays an important role in generating an equatorward coastal current and upwelling. Bottom topography is shown to be an important mechanism for intensifying and trapping currents near the coast, weakening subsurface currents and intensifying eddies off capes. Overall, the results of the study compare well with available observations in the LCS.
Publisher:
ISBN: 9781423507369
Category :
Languages : en
Pages : 117
Book Description
To investigate the role of wind forcing, bottom topography and thermohaline gradients in the Leeuwin Current System (LCS) , several experiments are conducted with a sigma coordinate primitive equation model on a beta- plane. Results show that the LCS is an anomalous eastern boundary current (EBC) that generates a coastal poleward current, an equatorward undercurrent, and highly energetic mesoscale features such as meanders and eddies. Thermohaline gradient effects were shown to be the primary mechanism in the generation of a poleward (equatorward) current (undercurrent) , eddies and meanders in the LCS. Inshore of the poleward surface flow, next to the coast, wind forcing plays an important role in generating an equatorward coastal current and upwelling. Bottom topography is shown to be an important mechanism for intensifying and trapping currents near the coast, weakening subsurface currents and intensifying eddies off capes. Overall, the results of the study compare well with available observations in the LCS.
A Numerical Study of the Forcing Mechanisms of the Leeuwin Current System
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 117
Book Description
To investigate the role of wind forcing, bottom topography and thermohaline gradients in the Leeuwin Current System (LCS) , several experiments are conducted with a sigma coordinate primitive equation model on a beta- plane. Results show that the LCS is an anomalous eastern boundary current (EBC) that generates a coastal poleward current, an equatorward undercurrent, and highly energetic mesoscale features such as meanders and eddies. Thermohaline gradient effects were shown to be the primary mechanism in the generation of a poleward (equatorward) current (undercurrent) , eddies and meanders in the LCS. Inshore of the poleward surface flow, next to the coast, wind forcing plays an important role in generating an equatorward coastal current and upwelling. Bottom topography is shown to be an important mechanism for intensifying and trapping currents near the coast, weakening subsurface currents and intensifying eddies off capes. Overall, the results of the study compare well with available observations in the LCS.
Publisher:
ISBN:
Category :
Languages : en
Pages : 117
Book Description
To investigate the role of wind forcing, bottom topography and thermohaline gradients in the Leeuwin Current System (LCS) , several experiments are conducted with a sigma coordinate primitive equation model on a beta- plane. Results show that the LCS is an anomalous eastern boundary current (EBC) that generates a coastal poleward current, an equatorward undercurrent, and highly energetic mesoscale features such as meanders and eddies. Thermohaline gradient effects were shown to be the primary mechanism in the generation of a poleward (equatorward) current (undercurrent) , eddies and meanders in the LCS. Inshore of the poleward surface flow, next to the coast, wind forcing plays an important role in generating an equatorward coastal current and upwelling. Bottom topography is shown to be an important mechanism for intensifying and trapping currents near the coast, weakening subsurface currents and intensifying eddies off capes. Overall, the results of the study compare well with available observations in the LCS.
A Numerical Study of Mesoscale Eddies in a Two Layer Wind-driven Ocean
A Numerical Study of Mid-ocean Mesoscale Eddies
Author: William Brechner Owens
Publisher:
ISBN:
Category :
Languages : en
Pages : 208
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 208
Book Description
The Leeuwin Current and Its Eddies
A numerical study of mesoscale ocean eddy interaction with a marginal ice zone
On the Generation of Mesoscale Eddies and Their Interaction with the Oceanic General Circulation
Author: William R. Holland
Publisher:
ISBN:
Category : Eddies
Languages : en
Pages : 126
Book Description
Publisher:
ISBN:
Category : Eddies
Languages : en
Pages : 126
Book Description
The Role of the Planetary Beta Effect on Currents and Eddies in the Leeuwin Current System
Author: Troy J. Tworek
Publisher:
ISBN: 9781423534174
Category : Eddies
Languages : en
Pages : 182
Book Description
To investigate the effect of the role played by planetary beta in the generation and maintenance of the Leeuwin Current System (LCS), several numerical experiments are conducted with varying Coriolis parameterizations (f- plane or beta-plane). The seasonal effects of thermal gradients, wind forcing and North West Shelf (NWS) waters are also systematically explored in the numerical experiments. Additionally, the generation mechanisms for undercurrents along both the western and southern coasts of Australia are investigated. Although surface currents, undercurrents, and mesoscale activity are present in both the f-plane and beta-plane experiments, those run on a beta-plane show a more realistic depiction of these features due to the significant role played by the planetary beta effect in the LCS. The combination of thermal forcing, wind forcing, and NWS waters were found to be essential to maintain the highly seasonally varying LCS. Alongshore temperature gradients, which are generated at deeper levels by the strong flow of the Leeuwin Current, are sufficient to establish and maintain an equatorward (westward) undercurrent along western (southern) Australia.
Publisher:
ISBN: 9781423534174
Category : Eddies
Languages : en
Pages : 182
Book Description
To investigate the effect of the role played by planetary beta in the generation and maintenance of the Leeuwin Current System (LCS), several numerical experiments are conducted with varying Coriolis parameterizations (f- plane or beta-plane). The seasonal effects of thermal gradients, wind forcing and North West Shelf (NWS) waters are also systematically explored in the numerical experiments. Additionally, the generation mechanisms for undercurrents along both the western and southern coasts of Australia are investigated. Although surface currents, undercurrents, and mesoscale activity are present in both the f-plane and beta-plane experiments, those run on a beta-plane show a more realistic depiction of these features due to the significant role played by the planetary beta effect in the LCS. The combination of thermal forcing, wind forcing, and NWS waters were found to be essential to maintain the highly seasonally varying LCS. Alongshore temperature gradients, which are generated at deeper levels by the strong flow of the Leeuwin Current, are sufficient to establish and maintain an equatorward (westward) undercurrent along western (southern) Australia.