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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.
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.
Author: Wendy A. Towle Publisher: ISBN: 9781423523710 Category : Languages : en Pages : 97
Book Description
To investigate planetary and topographic beta effects on classical as well as unique features in the northern Canary Current system (NCCS), several numerical experiments using the Princeton Ocean Model are explored To isolate the dependence of Coriolis parameterization (beta-plane vs, f-plane) from the topographic beta effect, the first (last) two experiments use a flat bottom (topography), In all experiments, classical eastern boundary condition (EBC) features are produced including an offshore surface equatorward meandering jet, coastal surface and subsurface poleward currents, upwelling, meanders, eddies and filaments, Due to the beta effect, the surface coastal jet does not have to be confined to within a Rossby radius of deformation of the coast, The beta effect also plays an important role in the development and westward propagation of Meddies, a unique feature of the NCCS, Bottom topography is shown to play an important role in narrowing, intensifying, and trapping coastal currents, These results show that, while wind forcing is the primary mechanism for generating classical EEC features, planetary and topographic beta also play important roles in the generation, evolution, and maintenance of classical as well as unique features in the NCCS,
Author: Patrick J. Murray Publisher: ISBN: 9781423536468 Category : Languages : en Pages : 114
Book Description
To investigate the role of planetary beta on classical as well as unique features in the northern Canary Current System (NCCS), four numerical experiments are conducted with varying Coriolis parameterizations (f-plane or beta plane). The first two experiments use a closed boundary and annual salinity forcing for the Mediterranean Outflow (MO). The latter two experiments use an open Mediterranean Sea at the Strait of Gibraltar and seasonal forcing for MO to permit a more accurate investigation of the role of the beta effect on subsurface spreading of MO and Meddies. All four experiments use seasonal climatological winds and seasonal thermohaline gradients along the western boundary to force the model. Experiments run on a beta-plane (Experiments 2 and 4) accurately portray classical eastern boundary current (EBC) mesoscale features. In addition, these experiments depict unique NCCS features associated with a large embayment (the Gulf of Cadiz), poleward spreading of MO, and the generation of Meddies. Experiments run on an f-plane (Experiments 1 and 3) show the unrealistic dominance of a continuously strengthening equatorward jet that inhibits development of classical EBC and unique NCCS features. The complex upper layer and subsurface flow regimes of Experiment 4 most realistically portray currents, mesoscale features and Meddies similar to NCCS observations.
Author: Patrick J. Murray Publisher: ISBN: Category : Languages : en Pages : 98
Book Description
To investigate the role of planetary beta on classical as well as unique features in the northern Canary Current System (NCCS), four numerical experiments are conducted with varying Coriolis parameterizations (f-plane or beta plane). The first two experiments use a closed boundary and annual salinity forcing for the Mediterranean Outflow (MO). The latter two experiments use an open Mediterranean Sea at the Strait of Gibraltar and seasonal forcing for MO to permit a more accurate investigation of the role of the beta effect on subsurface spreading of MO and Meddies. All four experiments use seasonal climatological winds and seasonal thermohaline gradients along the western boundary to force the model. Experiments run on a beta-plane (Experiments 2 and 4) accurately portray classical eastern boundary current (EBC) mesoscale features. In addition, these experiments depict unique NCCS features associated with a large embayment (the Gulf of Cadiz), poleward spreading of MO, and the generation of Meddies. Experiments run on an f-plane (Experiments 1 and 3) show the unrealistic dominance of a continuously strengthening equatorward jet that inhibits development of classical EBC and unique NCCS features. The complex upper layer and subsurface flow regimes of Experiment 4 most realistically portray currents, mesoscale features and Meddies similar to NCCS observations.
Author: Publisher: ISBN: Category : Ocean currents Languages : en Pages : 97
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.
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.
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.
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.
Author: Robyn L. Phillips Publisher: ISBN: 9781423507093 Category : Languages : en Pages : 107
Book Description
To investigate the role of wind forcing, bottom topography and thermohaline gradients in the Leeuwin current System (LCS) off western and southern Australia, several experiments are conducted with a sigma coordinate primitive equation model on a beta-plane. Results show that off the west (southern) coast the LCS is an anomalous eastern boundary current system that generates a coastal poleward (eastward) current, an equatorward (westward) undercurrent, and highly energetic mesoscale features such as meanders and eddies. Off the west coast, thermaohaline forcing, wind forcing and bottom topography all play important roles: Thermaohaline gradient effects are shown to be the primary mechanism in the generation of the poleward current, equatorward undercurrent, eddies and meanders. Inshore of the poleward surface flow, next to the coast, wind forcing also plays an important role in generating an equatorward coastal current and upwelling. Bottom topography is responsible for strengthening and trapping currents near the coast, intensifying eddies off capes and in preventing the undercurrent from becoming the dominant surface flow. Bottom topography is also shown to play a dominant role off the southern coast in trapping the eastward Leeuwin Current and the westward Flinders Current over the shelf break and slope, respectively. Overall, the results of the study compare well with available observations and previous studies of the LCS.
Author: Troy J. Tworek
Author: Troy J. Tworek
Author: Wendy A. Towle
Author: Patrick J. Murray
Author: Patrick J. Murray
Author: 
Author: 
Author: Richard A. Kennedy, Jr.
Author: 
Author: Michael Joseph Meuleners
Author: Robyn L. Phillips