Monitoring the Kuroshio Extension with Dynamically Constrained Synthesis of the Acoustic Tomography, Satellite Altimeter and in situ Data

Lebedev, K. V.; Yaremchuk, Max; Mitsudera, Humio; Nakano, Iwao; Yuan, Gang

doi:10.1023/b:joce.0000009568.06949.c5

Cited by 24 publications

(13 citation statements)

References 16 publications

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“…Here the eddy-mean flow interaction process is very nonlocal (Chen 2013;Chen et al 2014); barotropic instability is as important as baroclinic instability and eddies feed energy back to the mean flow downstream of the KE jet (e.g., Qiu 1995;Hurlburt and Metzger 1998;Lebedev et al 2003;Waterman et al 2011;Waterman and Hoskins 2013). Thus, the wave speed here from the POP model could differ from that based on the instability analysis above.…”

Section: ) Critical Layer Depth From the Radon Approachmentioning

confidence: 99%

Isopycnal Eddy Diffusivities and Critical Layers in the Kuroshio Extension from an Eddying Ocean Model

Chen

McClean

Gille

et al. 2014

Journal of Physical Oceanography

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High spatial resolution isopycnal diffusivities are estimated in the Kuroshio Extension (KE) region (288-408N, 1208-1908E) from a global 1 /108 Parallel Ocean Program (POP) simulation. The numerical float tracks are binned using a clustering approach. The number of tracks in each bin is thus roughly the same leading to diffusivity estimates that converge better than those in bins defined by a regular geographic grid. Cross-stream diffusivities are elevated in the southern recirculation gyre region, near topographic obstacles and downstream in the KE jet, where the flow has weakened. Along-stream diffusivities, which are much larger than cross-stream diffusivities, correlate well with the magnitudes of eddy velocity. The KE jet suppresses crossstream mixing only in some longitude ranges. This study estimates the critical layer depth both from linear local baroclinic instability analysis and from eddy phase speeds in the POP model using the Radon transform. The latter is a better predictor of large mixing length in the cross-stream direction. Critical layer theory is most applicable in the intense jet regions away from topography.

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Section: ) Critical Layer Depth From the Radon Approachmentioning

confidence: 99%

Isopycnal Eddy Diffusivities and Critical Layers in the Kuroshio Extension from an Eddying Ocean Model

Chen

McClean

Gille

et al. 2014

Journal of Physical Oceanography

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“…In the past, stochastic inverse methods have most commonly been used to interpret acoustic travel times to obtain ocean temperatures and currents (e.g., Munk et al, 1995). With recent improvements in the vertical resolution and realism of ocean circulation models, acoustic travel times are now being used to directly constrain the models, taking advantage of the models to combine acoustic (and other data) from different times and locations in a way that is consistent with ocean dynamics (e.g., Lebedev et al, 2003). Time-evolving ocean circulation models implicitly supply a large amount of information about the ocean by enforcing the conservation of mass, momentum, and other properties.…”

Section: Tomographic Instrumentation and Signal Processingmentioning

confidence: 99%

“…Long-range acoustic propagation paths used in tomography are also sensitive to such features. One-second changes in travel time are observed as a result of Gulf Stream or Kuroshio meanders, for example (Spiesberger et al, 1983;Lebedev et al, 2003).…”

Section: Acoustics Addressing Ocean Observing Needs Discoverymentioning

confidence: 99%

Observing the Oceans Acoustically

et al. 2019

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“…One such program is the Alfred Wegener Institute's (AWI) long‐term Moored Array [ Schauer et al ., ; Beszczynska‐Möller et al ., ]. The use of data assimilation techniques with ocean models is essential to assess the relative impact of the various data types on the ocean state estimates [ Gaillard , ; Lebedev et al ., ; Rémy et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Time series of temperature in Fram Strait determined from the 2008–2009 DAMOCLES acoustic tomography measurements and an ocean model

Sagen¹,

Dushaw²,

Skarsoulis

et al. 2016

JGR Oceans

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Individual ray arrivals were not observed. Rather, the arrival patterns consisted of a single, stable, broad arrival pulse of about 100 ms duration. Travel time variations of 60.15 s recorded the vigorous mesoscale environment of the region and the seasonal cycle. To estimate ocean temperature from the tomography data an inverse scheme employed a high-resolution ocean model for Fram Strait as the reference ocean. The information from the tomographic measurements is primarily average temperature. Estimated temperatures, averaged over 0-1000 m depth and over range, had a mean of 1.118C and variations of 60.338C; the uncertainty of the tomography estimates was about 60m8C. Agreement with an alternate inverse approach based on EOFs and a Markov Chain Monte Carlo inversion scheme relying on a matched-peak approach was excellent, indicating a robust estimate for ocean temperature. The inverse estimates for average temperature agreed with the equivalent estimates from hydrographic sections obtained along the acoustic path at the start and end of the program. Among other deficiencies, the ocean model greatly underestimated the intensity of the mesoscale fluctuations and exhibited a warm bias of about 0.388C in section-averaged temperature. Tomographic measurements in Fram Strait offer unique large-scale temperature constraints for ocean models through data assimilation. It is anticipated that these constraints will lead to more accurate estimates of the circulation and transports in Fram Strait.

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Monitoring the Kuroshio Extension with Dynamically Constrained Synthesis of the Acoustic Tomography, Satellite Altimeter and in situ Data

Cited by 24 publications

References 16 publications

Isopycnal Eddy Diffusivities and Critical Layers in the Kuroshio Extension from an Eddying Ocean Model

Isopycnal Eddy Diffusivities and Critical Layers in the Kuroshio Extension from an Eddying Ocean Model

Observing the Oceans Acoustically

Time series of temperature in Fram Strait determined from the 2008–2009 DAMOCLES acoustic tomography measurements and an ocean model

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