scholarly journals Turbulent kinetic energy of the ocean winds over the Kuroshio Extension from QuikSCAT winds (1999-2009)

2017 ◽  
Vol 122 (6) ◽  
pp. 4482-4499 ◽  
Author(s):  
Kai Yu ◽  
Changming Dong ◽  
Gregory P. King
Keyword(s):  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Kuroshio Extension ◽  
Ocean Winds ◽  
The Kuroshio ◽  
Quikscat Winds

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 The Instabilities and Multiscale Energetics Underlying the Mean–Interannual–Eddy Interactions in the Kuroshio Extension Region

2016 ◽  
Vol 46 (5) ◽  
pp. 1477-1494 ◽  
Author(s):  
Yang Yang ◽  
X. San Liang
Keyword(s):  
Kinetic Energy ◽  
Kuroshio Extension ◽  
Wave Mode ◽  
Mean Flow ◽  
Energy Transfers ◽  
The Mean ◽  
Interannual Fluctuations ◽  
Recirculation Gyre ◽  
The Kuroshio ◽  
Kuroshio Extension Region

AbstractUsing a recently developed energetics diagnostic methodology, namely, the localized multiscale energy and vorticity analysis (MS-EVA), this study investigates the intricate nonlinear mutual interactions among the decadally modulating mean flow, the interannual fluctuations, and the transient eddies in the Kuroshio Extension region. It is found that the mean kinetic energy maximizes immediately east of the Izu–Ogasawara Ridge, while the transient eddy kinetic energy does not peak until 400 km away downstream. The interannual variabilities, which are dominated by a jet-trapped Rossby wave mode, provide an energy reservoir comparable to the other counterparts. In the upstream, strong localized barotropic and baroclinic transfers from the mean flow to the eddies are observed, whereas those from the interannual variabilities are not significant. Besides fueling the eddies, the unstable mean jet also releases energy to the interannual-scale processes. Between 144° and 154°E, both transfers from the mean flow and the interannual variabilities are important for the eddy development. Farther downstream, eddies are found to drive the mean flow on both the kinetic energy (KE) and available potential energy (APE) maps. They also provide KE to the interannual variabilities but obtain APE from the latter. The gained eddy APE is then converted to eddy KE through buoyancy conversion. Upscale energy transfers are observed in the northern and southern recirculation gyre (RG) regions. In these regions, the interannual–eddy interaction exhibits different scenarios: the eddies lose KE to the interannual processes in the northern RG region, while gaining KE in the southern RG region.

scholarly journals Effect of Mesoscale Eddies on Subtropical Mode Water Variability from the Kuroshio Extension System Study (KESS)

2007 ◽  
Vol 37 (4) ◽  
pp. 982-1000 ◽  
Author(s):  
Bo Qiu ◽  
Shuiming Chen ◽  
Peter Hacker
Keyword(s):  
Kinetic Energy ◽  
Energy State ◽  
Kuroshio Extension ◽  
Mesoscale Eddies ◽  
System Study ◽  
Mode Water ◽  
Eddy Activity ◽  
Extension System ◽  
Recirculation Gyre ◽  
The Kuroshio

Abstract Forty-eight profiling floats have been deployed in the Kuroshio Extension (KE) region since May 2004 as part of the Kuroshio Extension System Study (KESS) project. By combining the float temperature–salinity measurements with satellite altimetry data, this study investigates the role played by mesoscale eddies in controlling the property changes in North Pacific Subtropical Mode Water (STMW). Following a 3-yr period of low eddy activity in 2002–04, the KE showed a transition to a high eddy kinetic energy state in 2005. This transition is the result of delayed oceanic response to the 2002 shift in the basin-scale surface wind forcing in connection with the Pacific decadal oscillation. The high eddy kinetic energy state of the KE is characterized by successive shedding of strong cold-core rings into the recirculation gyre, resulting from the interaction of the KE jet with the Shatsky Rise or the preexisting cutoff rings. By transporting northern-origin, high-potential-vorticity (PV) KE water into the recirculation gyre, the enhanced eddy activity affects STMW in two ways: first, it hinders the formation of deep winter mixed layer (hence the source for STMW) by modifying the upper-ocean stratification and, second, it provides a direct high-PV source to mix with the surrounding low-PV STMW. The eddies’ influence upon STMW is observed to be both significant in magnitude and efficient in time. Relative to 2004, the PV signal in the core of STMW was reduced by one-half in 2005, and this weakening of STMW’s intensity occurred within a period of less than 7 months. This result supports recent findings by the authors based on historical temperature data that the variability in STMW formation depends more sensitively on the dynamic state of the KE than on the overlying atmospheric conditions.

Biophysical variability in the Kuroshio Extension from altimeter and SeaWiFS

OCEANS 2009 ◽  
2009 ◽  
Author(s):  
Peter C. Chu ◽  
Yu-heng Kuo
Keyword(s):  
Kuroshio Extension ◽  
The Kuroshio

Cold air outbreak over the Kuroshio extension region

OCEANS 2009 ◽  
2009 ◽  
Author(s):  
T. G. Jensen ◽  
T. Campbell ◽  
T. A. Smith ◽  
R. J. Small ◽  
R. Allard
Keyword(s):  
Kuroshio Extension ◽  
Cold Air ◽  
Cold Air Outbreak ◽  
The Kuroshio ◽  
Kuroshio Extension Region
Sign in / Sign up

Export Citation Format

Share Document