Spatial structure of anticyclonic eddies in the Algerian basin (Mediterranean Sea) analyzed using the Okubo–Weiss parameter

Isern‐Fontanet, Jordi; Font, Jordi; Garcı́a-Ladona, Emilio; Emelianov, Mikhail; Millot, Claude; Taupier‐Letage, Isabelle

doi:10.1016/j.dsr2.2004.09.013

Cited by 121 publications

(88 citation statements)

References 49 publications

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“…We can easily extract from this by continuity the position and extension of 98-1's core in the full time series of surface maps (one every ten days, not shown here, the same frequency as SLA maps built by CLS), and compute the average westward propagation velocity of the eddy centre, which was 2.7 km/day. It should be taken into account that this method separates the eddy cores neatly, while the circulation cells do not display a similar axial symmetry, have a higher degree of temporal variability and are more smoothly embedded in the background field (Isern-Fontanet et al, 2004). Other means of observing ocean eddies, such as SST images and drifters' trajectories, do not discriminate the two regions, and therefore they usually highlight eddies as areas bigger than their cores.…”

Section: Results and Conclusionmentioning

confidence: 99%

Tracking a big anticyclonic eddy in the western Mediterranean Sea

Font¹,

Isern‐Fontanet²,

Salas³

2004

Sci. Mar.

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Section: Results and Conclusionmentioning

confidence: 99%

Tracking a big anticyclonic eddy in the western Mediterranean Sea

Font¹,

Isern‐Fontanet²,

Salas³

2004

Sci. Mar.

Self Cite

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“…Various dynamical criteria could be used to quantify the location and the size of a coherent vortex (Pasquero et al 2001;Isern-Fontanet et al 2004). However, as far as crossshelf transport is concerned, we define a vortex as a coherent structure able to trap and isolate a water parcel in its core.…”

Section: Nonlinear Saturation and Eddy Generationmentioning

confidence: 99%

Shelf Impact on Buoyant Coastal Current Instabilities

Pennel

Stegner

Béranger

2012

Journal of Physical Oceanography

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The impact of shelf slope on the linear stability of buoyant coastal currents and on the nonlinear formation of coastal meanders and eddies is investigated. The authors consider a simplified two-layer stratification in cylindrical geometry where a buoyant surface current flows along the coast above a denser water, with a flat bottom or steep shelves. Simulations were performed using the Nucleus for European Modelling of the Ocean (NEMO) ocean global circulation model. The initial state of these simulations was defined according to laboratory experiments performed in the same configuration. Comparisons between laboratory and numerical results highlight the role of momentum diffusion and of the initial perturbations amplitude. The authors' results confirm that the topographic parameter To (ratio between the shelf slope and the isopycnal slope of the current) is the relevant parameter to quantify the shelf impact on the linear and nonlinear dynamics of the surface current. When the evolution of the buoyant coastal current is controlled by the baroclinic instability, the increase of To yields a selection of smaller unstable wavelengths and a decrease of the unstable growth rates. For finite values of To, a complete stabilization of the surface current can be reached. The typical radius of the first eddies generated by the coastal current is set by the linear stage of the baroclinic instability. However, secondary nonlinear processes may lead to larger or smaller structures. The authors exhibit a new dynamical sequence, leading to the formation of submesoscale cyclonic eddies over a steep shelf by splitting of mesoscale eddies. These cyclonic eddies trap and transport water masses and may play an important role in the cross-shelf exchanges.

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“…In this study, a free-threshold eddy identification algorithm with the SLA data is employed. This algorithm is based on the vector geometry method [21] and Okubo-Weiss method [22]. We assume that the ocean is in a steady state; therefore, it is examined by considering only the balance of the pressure gradient and Coriolis force.…”

Section: Detection Algorithmmentioning

confidence: 99%

Statistical Characteristics of Mesoscale Eddies in the North Pacific Derived from Satellite Altimetry

Cheng

Zheng

et al. 2014

Remote Sensing

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Abstract:The sea level anomaly data derived from satellite altimetry are analyzed to investigate statistical characteristics of mesoscale eddies in the North Pacific. Eddies are detected by a free-threshold eddy identification algorithm. The results show that the distributions of size, amplitude, propagation speed, and eddy kinetic energy of eddy follow the Rayleigh distribution. The most active regions of eddies are the Kuroshio Extension region, the Subtropical Counter Current zone, and the Northeastern Tropical Pacific region. By contrast, eddies are seldom observed around the center of the eastern part of the North Pacific Subarctic Gyre. The propagation speed and kinetic energy of cyclonic and anticyclonic eddies are almost the same, but anticyclonic eddies possess greater lifespans, sizes, and amplitudes than those of cyclonic eddies. Most eddies in the North Pacific propagate westward except in the Oyashio region. Around the northeastern tropical Pacific and the California currents, cyclonic and anticyclonic eddies propagate westward with slightly equatorward (197° average azimuth relative to east) and poleward (165°) deflection, respectively. This implies that the background current may play an important role in formation of the eddy pathway patterns.

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Spatial structure of anticyclonic eddies in the Algerian basin (Mediterranean Sea) analyzed using the Okubo–Weiss parameter

Cited by 121 publications

References 49 publications

Tracking a big anticyclonic eddy in the western Mediterranean Sea

Tracking a big anticyclonic eddy in the western Mediterranean Sea

Shelf Impact on Buoyant Coastal Current Instabilities

Statistical Characteristics of Mesoscale Eddies in the North Pacific Derived from Satellite Altimetry

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