The Experts below are selected from a list of 16962 Experts worldwide ranked by ideXlab platform
Juliet Hermes - One of the best experts on this subject based on the ideXlab platform.
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agulhas current Meanders facilitate shelf slope exchange on the eastern agulhas bank
Journal of Geophysical Research, 2018Co-Authors: N Malan, Bjorn C Backeberg, Arne Biastoch, Jonathan V Durgadoo, Annette Samuelsen, C J C Reason, Juliet HermesAbstract:Large solitary Meanders are arguably the dominant mode of variability in the Agulhas Current. Observational studies have shown that these large Meanders are associated with strong upwelling velocities and affect the shelf circulation for over 100 days per year. Here 10-year time series from two ocean general circulation models are used to create a composite picture of the Agulhas Current and its interactions with the shelf circulation in Meandering and nonMeandering modes. Both models show good agreement with the size, propagation speed, and frequency of observed Meanders. These composite Meanders are then used to examine the response of shelf waters to the onset of large Meanders, with the use of model output enabling the dynamics at depth to be explored. Results show a composite mean warming of up to 3°C of depth-averaged temperature along the shelf edge associated with an intrusion of the current jet onto the shelf driven by an intensification of the flow along the leading edge of large Meanders. However, this intensification of flow results in cooling of bottom waters, driving cold events at the shelf break of <10°C at 100 m. Thus, the intensification of the current jet associated with large Meander events appears to drive strong up and downwelling events across the inshore front of the Agulhas Current, facilitating shelf-slope exchange.
Timothy Sickbert - One of the best experts on this subject based on the ideXlab platform.
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stream water bypass through a Meander neck laterally extending the hyporheic zone
Hydrogeology Journal, 2006Co-Authors: Eric W Peterson, Timothy SickbertAbstract:A Meander lobe neck diverts stream water into a hyporheic flow path adjacent to a low gradient stream, Little Kickapoo Creek, Illinois, USA. Hyporheic processes have been well-documented in surface water–groundwater mixing zones underlying and directly adjacent to streams. Alluvial aquifers underlying Meander necks provide a further extension of the hyporheic zone. Hydraulic head and temperature data, collected from a set of wells across a Meander neck, show stream water moves through the Meander neck. The hydraulic gradient across the Meander neck (0.006) is greater than the stream gradient (0.003) between the same points, driving the bypass. Rapid subsurface response to elevated stream stage shows a hydraulic connection between the stream and the alluvial aquifer. Temperature data and a Peclet number (Pe) of 43.1 indicate that thermal transport is dominated by advection from the upstream side to the downstream side of the Meander neck. The temperature observed within the alluvial aquifer correlates with seasonal temperature variation. Together, the pressure and temperature data indicate that water moves across the Meander neck. The inflow of stream water through the Meander neck suggests that the Meander system may host biogeochemical hyporheic zone processes.
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stream water bypass through a Meander neck laterally extending the hyporheic zone
Hydrogeology Journal, 2006Co-Authors: Eric W Peterson, Timothy SickbertAbstract:A Meander lobe neck diverts stream water into a hyporheic flow path adjacent to a low gradient stream, Little Kickapoo Creek, Illinois, USA. Hyporheic process- es have been well-documented in surface water-ground- water mixing zones underlying and directly adjacent to streams. Alluvial aquifers underlying Meander necks provide a further extension of the hyporheic zone. Hydraulic head and temperature data, collected from a set of wells across a Meander neck, show stream water moves through the Meander neck. The hydraulic gradient across the Meander neck (0.006) is greater than the stream gradient (0.003) between the same points, driving the bypass. Rapid subsurface response to elevated stream stage shows a hydraulic connection between the stream and the alluvial aquifer. Temperature data and a Peclet number (Pe) of 43.1 indicate that thermal transport is dominated by advection from the upstream side to the downstream side of the Meander neck. The temperature observed within the alluvial aquifer correlates with
Toshiyuki Hibiya - One of the best experts on this subject based on the ideXlab platform.
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effects of koshu seamount on the development of baroclinic instability leading to the kuroshio large Meander
Journal of Physical Oceanography, 2017Co-Authors: Yuki Tanaka, Toshiyuki HibiyaAbstract:AbstractThe Kuroshio south of Japan shows bimodal path fluctuations between the large Meander (LM) path and the nonlarge Meander (NLM) path. The transition from the NLM path to the LM path is triggered by a small Meander generated off southwestern Japan. The small Meander first propagates eastward (downstream) along the Kuroshio and then rapidly amplifies over Koshu Seamount, located about 200 km south of Japan, leading to the formation of the LM path of the Kuroshio. Although Koshu Seamount is essential for the rapid amplification of the small Meander, the underlying physical mechanism is not fully understood. In this study, the role of Koshu Seamount is revisited using a two-layer quasi-geostrophic model that takes into account the effects of bottom topography. Numerical experiments show that the transition from the NLM path to the LM path can be successfully reproduced only when bottom topography mimicking Koshu Seamount is incorporated. In this case, the upper-layer Meander trough is rapidly amplified...
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interaction between the trigger Meander of the kuroshio and the abyssal anticyclone over koshu seamount as seen in the reanalysis data
Geophysical Research Letters, 2009Co-Authors: Takahiro Endoh, Toshiyuki HibiyaAbstract:[1] The JCOPE (Japan Coastal Ocean Predictability Experiment) reanalysis data is analyzed to examine the transition from the non-large Meander path to the large Meander path of the Kuroshio that occurred in 2004. It was preceded by the generation of “trigger Meander” off the southeastern coast of Kyushu, which then propagated eastward. After passing Cape Shiono-misaki, the trigger Meander amplified rapidly over Koshu Seamount (located about 200 km to the south of Cape Shiono-misaki) where the accompanying abyssal anticyclone was significantly enhanced. Strong downwelling occurred upstream of the Meander trough where the abyssal anticyclone crossed the Kuroshio, causing the vertical vortex stretching (shrinking) in the upper (lower) ocean; the resulting enhanced abyssal anticyclone further amplified the Meander trough in the upper ocean. All of these features agree well with the model results suggesting the importance of baroclinic instability over Koshu Seamount in the formation of the large Meander path.
Bjorn C Backeberg - One of the best experts on this subject based on the ideXlab platform.
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agulhas current Meanders facilitate shelf slope exchange on the eastern agulhas bank
Journal of Geophysical Research, 2018Co-Authors: N Malan, Bjorn C Backeberg, Arne Biastoch, Jonathan V Durgadoo, Annette Samuelsen, C J C Reason, Juliet HermesAbstract:Large solitary Meanders are arguably the dominant mode of variability in the Agulhas Current. Observational studies have shown that these large Meanders are associated with strong upwelling velocities and affect the shelf circulation for over 100 days per year. Here 10-year time series from two ocean general circulation models are used to create a composite picture of the Agulhas Current and its interactions with the shelf circulation in Meandering and nonMeandering modes. Both models show good agreement with the size, propagation speed, and frequency of observed Meanders. These composite Meanders are then used to examine the response of shelf waters to the onset of large Meanders, with the use of model output enabling the dynamics at depth to be explored. Results show a composite mean warming of up to 3°C of depth-averaged temperature along the shelf edge associated with an intrusion of the current jet onto the shelf driven by an intensification of the flow along the leading edge of large Meanders. However, this intensification of flow results in cooling of bottom waters, driving cold events at the shelf break of <10°C at 100 m. Thus, the intensification of the current jet associated with large Meander events appears to drive strong up and downwelling events across the inshore front of the Agulhas Current, facilitating shelf-slope exchange.
Eric W Peterson - One of the best experts on this subject based on the ideXlab platform.
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stream water bypass through a Meander neck laterally extending the hyporheic zone
Hydrogeology Journal, 2006Co-Authors: Eric W Peterson, Timothy SickbertAbstract:A Meander lobe neck diverts stream water into a hyporheic flow path adjacent to a low gradient stream, Little Kickapoo Creek, Illinois, USA. Hyporheic processes have been well-documented in surface water–groundwater mixing zones underlying and directly adjacent to streams. Alluvial aquifers underlying Meander necks provide a further extension of the hyporheic zone. Hydraulic head and temperature data, collected from a set of wells across a Meander neck, show stream water moves through the Meander neck. The hydraulic gradient across the Meander neck (0.006) is greater than the stream gradient (0.003) between the same points, driving the bypass. Rapid subsurface response to elevated stream stage shows a hydraulic connection between the stream and the alluvial aquifer. Temperature data and a Peclet number (Pe) of 43.1 indicate that thermal transport is dominated by advection from the upstream side to the downstream side of the Meander neck. The temperature observed within the alluvial aquifer correlates with seasonal temperature variation. Together, the pressure and temperature data indicate that water moves across the Meander neck. The inflow of stream water through the Meander neck suggests that the Meander system may host biogeochemical hyporheic zone processes.
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stream water bypass through a Meander neck laterally extending the hyporheic zone
Hydrogeology Journal, 2006Co-Authors: Eric W Peterson, Timothy SickbertAbstract:A Meander lobe neck diverts stream water into a hyporheic flow path adjacent to a low gradient stream, Little Kickapoo Creek, Illinois, USA. Hyporheic process- es have been well-documented in surface water-ground- water mixing zones underlying and directly adjacent to streams. Alluvial aquifers underlying Meander necks provide a further extension of the hyporheic zone. Hydraulic head and temperature data, collected from a set of wells across a Meander neck, show stream water moves through the Meander neck. The hydraulic gradient across the Meander neck (0.006) is greater than the stream gradient (0.003) between the same points, driving the bypass. Rapid subsurface response to elevated stream stage shows a hydraulic connection between the stream and the alluvial aquifer. Temperature data and a Peclet number (Pe) of 43.1 indicate that thermal transport is dominated by advection from the upstream side to the downstream side of the Meander neck. The temperature observed within the alluvial aquifer correlates with
