scholarly journals A comparison of surface eddy kinetic energy and Reynolds stresses in the Gulf Stream and the Kuroshio Current systems from merged TOPEX/Poseidon and ERS-1/2 altimetric data

2001 ◽  
Vol 106 (C8) ◽  
pp. 16603-16622 ◽  
Author(s):  
N. Ducet ◽  
P.-Y. Le Traon
Keyword(s):  
Kinetic Energy ◽  
Gulf Stream ◽  
Kuroshio Current ◽  
Eddy Kinetic Energy ◽  
Reynolds Stresses ◽  
Altimetric Data ◽  
The Kuroshio ◽  
Current Systems

scholarly journals Instability-Driven Benthic Storms below the Separated Gulf Stream and the North Atlantic Current in a High-Resolution Ocean Model

2018 ◽  
Vol 48 (10) ◽  
pp. 2283-2303 ◽  
Author(s):  
René Schubert ◽  
Arne Biastoch ◽  
Meghan F. Cronin ◽  
Richard J. Greatbatch
Keyword(s):  
Energy Transfer ◽  
High Resolution ◽  
Kinetic Energy ◽  
North Atlantic ◽  
Gulf Stream ◽  
Eddy Kinetic Energy ◽  
North Atlantic Current ◽  
The North ◽  
The North Atlantic ◽  
Atlantic Current

AbstractBenthic storms are important for both the energy budget of the ocean and for sediment resuspension and transport. Using 30 years of output from a high-resolution model of the North Atlantic, it is found that most of the benthic storms in the model occur near the western boundary in association with the Gulf Stream and the North Atlantic Current, in regions that are generally collocated with the peak near-bottom eddy kinetic energy. A common feature is meander troughs in the near-surface jets that are accompanied by deep low pressure anomalies spinning up deep cyclones with near-bottom velocities of up to more than 0.5 m s−1. A case study of one of these events shows the importance of both baroclinic and barotropic instability of the jet, with energy being extracted from the jet in the upstream part of the meander trough and partly returned to the jet in the downstream part of the meander trough. This motivates examining the 30-yr time mean of the energy transfer from the (annual mean) background flow into the eddy kinetic energy. This quantity is shown to be collocated well with the region in which benthic storms and large increases in deep cyclonic relative vorticity occur most frequently, suggesting an important role for mixed barotropic–baroclinic instability-driven cyclogenesis in generating benthic storms throughout the model simulation. Regions of the largest energy transfer and most frequent benthic storms are found to be the Gulf Stream west of the New England Seamounts and the North Atlantic Current near Flemish Cap.

Mean and eddy kinetic energy of the Gulf Stream from multiyear underwater glider surveys

2020 ◽  
Author(s):  
Robert E. Todd
Keyword(s):  
Kinetic Energy ◽  
Gulf Stream ◽  
Three Dimensional ◽  
Eddy Kinetic Energy ◽  
Cape Cod ◽  
Western Boundary ◽  
Western Boundary Currents ◽  
Boundary Currents ◽  
Global Circulation Models ◽  
The North

<p>Subtropical western boundary currents play a key role in ocean energy storage and transport and are characterized by elevated mean and eddy kinetic energy. Due to a lack of spatially broad subsurface observations of velocity, most studies of kinetic energy in western boundary currents have relied on satellite-based estimates of surface geostrophic velocity. Since 2015, Spray autonomous underwater gliders have completed more than 175 crossings of the Gulf Stream distributed over more than 1,500 km in along-stream extent between between Miami, FL (~25°N) and Cape Cod, MA (~40°N). The observations include roughly 14,000 absolute ocean velocity profiles in the upper 1000 m. Novel three-dimensional estimates of mean and eddy kinetic energy are constructed along the western margin of the North Atlantic at 10-m vertical resolution. The horizontal and vertical distributions of mean and eddy kinetic energy are analyzed in light of existing independent estimates and theoretical expectations. Observation-based estimates of mean and eddy-kinetic energy such as these serve as important metrics for validation of global circulation models that must adequately represent western boundary currents.</p>

scholarly journals On the seasonal variability of eddy kinetic energy in the Gulf Stream region

2008 ◽  
Vol 35 (24) ◽  
Author(s):  
Xiaoming Zhai ◽  
Richard J. Greatbatch ◽  
Jan-Dirk Kohlmann
Keyword(s):  
Kinetic Energy ◽  
Gulf Stream ◽  
Seasonal Variability ◽  
Eddy Kinetic Energy

scholarly journals Mapping Circulation in the Kuroshio Extension with an Array of Current and Pressure Recording Inverted Echo Sounders

2010 ◽  
Vol 27 (3) ◽  
pp. 507-527 ◽  
Author(s):  
Kathleen A. Donohue ◽  
D. Randolph Watts ◽  
Karen L. Tracey ◽  
Andrew D. Greene ◽  
Maureen Kennelly
Keyword(s):  
Kinetic Energy ◽  
Kuroshio Extension ◽  
Eddy Kinetic Energy ◽  
Bottom Pressure ◽  
Geostrophic Velocity ◽  
Pressure Recording ◽  
Extension System ◽  
Improved Technique ◽  
Recirculation Gyre ◽  
The Kuroshio

Abstract The Kuroshio Extension System Study (KESS) aimed to quantify processes governing the variability of and the interaction between the Kuroshio Extension and the recirculation gyre. To meet this goal, a suite of instrumentation, including 43 inverted echo sounders equipped with bottom pressure gauges and current meters [current and pressure recording inverted echo sounders (CPIES)], was deployed. The array was centered on the first quasi-stationary meander crest and trough east of Japan, which is also the region of highest eddy kinetic energy. KESS was the first experiment to deploy a large quantity of these new CPIES instruments, and it was unique in that the instruments were deployed in water depths (5300–6400 m) close to their limit of operation. A comprehensive narrative of the methodology to produce mesoscale-resolving four-dimensional circulation fields of temperature, specific volume anomaly, and velocity from the KESS CPIES array is provided. In addition, an improved technique for removing pressure drift is introduced. Methodology and error estimates were verified with several independent datasets. Temperature error was lowest on the equatorward side of the Kuroshio Extension core and decreased with depth (1.5°C at 300 m, 0.3°C at 600 m, and <0.1°C below 1200 m). Velocity errors were highest in regions of strong eddy kinetic energy, within and south of the jet core. Near the surface, the error in geostrophic velocity between adjacent CPIES was typically 10 cm s−1, decreasing downward to 6 cm s−1 at 500-m depth and 5 cm s−1 below 800 m. The rms differences from pointwise current measurements are nearly twice as large as the geostrophic errors, because the pointwise velocities include submesoscale and ageostrophic contributions.

scholarly journals Variability of the Kuroshio Extension Jet, Recirculation Gyre, and Mesoscale Eddies on Decadal Time Scales

2005 ◽  
Vol 35 (11) ◽  
pp. 2090-2103 ◽  
Author(s):  
Bo Qiu ◽  
Shuiming Chen
Keyword(s):  
Kinetic Energy ◽  
Kuroshio Extension ◽  
Mesoscale Eddy ◽  
Low Frequency ◽  
Eddy Kinetic Energy ◽  
Mean Flow ◽  
Flow Intensity ◽  
Frequency Changes ◽  
Recirculation Gyre ◽  
The Kuroshio

Abstract Twelve years of sea surface height (SSH) data from multiple satellite altimeters are used to investigate the low-frequency changes and the interconnections of the Kuroshio Extension (KE) jet, its southern recirculation gyre, and their mesoscale eddy field. The dominant signal is characterized by the steady weakening of the KE jet/recirculation gyre from 1993 to 1996, followed by a gradual strengthening after 1997. During the weakening period of 1993–96, the KE path migrated southward in general, and this path migration reversed in direction during the strengthening period of the KE jet and recirculation gyre after 1997. By hindcasting the SSH signals using linear vorticity dynamics, it was found that weakening (strengthening) in the KE jet and recirculation gyre is consistent with westward propagation of negative (positive) SSH anomalies generating in the eastern North Pacific and strengthening during their westward propagation. When the KE jet and recirculation gyre were in a weak mode during 1996–2001, the regional eddy kinetic energy level was observed to be higher than when the jet and recirculation gyre were in a strong mode. This negative correlation between the mean flow intensity and the level of regional eddy kinetic energy is found in both the SSH data and the linear vorticity model to result from the migration of the KE jet inflow over the Izu–Ogasawara Ridge. When it is forced southward by the impinging negative SSH anomalies, the KE jet inflow rides over the ridge through a shallow segment, leading to large-amplitude downstream meanders. Impinging of positive SSH anomalies, on the other hand, strengthens the recirculation gyre and forces the inflow northward where it passes through a deep channel, minimizing the path perturbations in the downstream region.

scholarly journals Eddy-induced Heat Transport in the South China Sea

2021 ◽  
Author(s):  
Ruibin Ding ◽  
Jiliang Xuan ◽  
Tao Zhang ◽  
Lei Zhou ◽  
Feng Zhou ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
South China Sea ◽  
Heat Transport ◽  
South China ◽  
Eddy Kinetic Energy ◽  
The South China Sea ◽  
Kuroshio Intrusion ◽  
The South ◽  
China Sea ◽  
The Kuroshio

AbstractEddy-induced heat transport (EHT) in the South China Sea (SCS) is important for the heat budget. However, knowledge of its variability is limited owing to discrepancies arising from the limitation of the down-gradient method and uncertainties arising from numerical models. Herein, we investigated the spatiotemporal variability and dynamics of EHT using a well-validated assimilated model. In particular, to the southeast of Vietnam (SEV) and west of Luzon Strait (WLS), significant values of annual mean EHT are observed and most EHT is confined in the upper 400 m. EHT also exhibits significant seasonality, and the largest EHT amplitude in autumn at SEV is mainly driven by the wind stress curl, while that in winter at WLS is mainly related to the Kuroshio intrusion. Energy budget analysis reveals that both the barotropic and baroclinic instabilities increase the eddy kinetic energy in autumn at SEV, whereas only the barotropic instability contributes to the eddy kinetic energy at WLS in winter. Specially, an up-gradient EHT is observed at WLS in all four seasons, characterized by the same directions between EHT and mean temperature gradient. The up-gradient EHT at WLS is induced by the baroclinic instability through an inverse energy transfer, which is generated by the interaction between the Kuroshio intrusion and topography below the surface layer. Moreover, the most significant up-gradient EHT in winter shows a wave-like southwestward propagating pattern in the subsurface layer.

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