The eastern Mediterranean general circulation: features, structure and variability

Robinson, Allan R.; Golnaraghi, Maryam; Leslie, Wayne G.; Artegiani, A.; Hecht, A.; Lazzoni, E.; Michelato, A.; Sansone, E.; Theocharis, A.; Ünlüata, Ümi̇t

doi:10.1016/0377-0265(91)90021-7

Cited by 209 publications

(107 citation statements)

References 4 publications

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“…The circulation patterns suggest that the model can successfully reproduce all the main general circulation characteristics of the area (Mid Mediterranean Jet, Asia Minor Current, Rhodes cyclonic gyre, Mersa-Matruh and Shikmona anticyclonic gyres), revealed by the synthesis of the POEM data set (see Fig. 12 adapted from Robinson et al, 1991). Both winter and summer circulation patterns are very rich in mesoscale features, which are mainly intensified during the summer period.…”

Section: Circulation Patternsmentioning

confidence: 81%

“…The phenomenology of the area (Robinson et al, 1991) and previous modelling work (Lascaratos and Nittis, 1998) suggest that this is a very important boundary for the water mass exchange (inflowing waters of Atlantic origin and outflowing LIW waters) of the Levantine basin and thus, to a large extent controls both the general and the thermohaline circulation of the area.…”

Section: Nesting Techniquementioning

confidence: 88%

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A one-way nested eddy resolving model of the Aegean and Levantine basins: implementation and climatological runs

2003

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Abstract. The present study deals with the implementation of an eddy resolving model of the Levantine and Aegean basins and its one-way nesting with a coarse resolution (1/8 • × 1/8 • ) global Mediterranean general circulation model. The modelling effort is done within the framework of the Mediterranean Forecasting System Pilot Project as an initiative towards real-time forecasting within the eastern Mediterranean region.The performed climatological runs of the nested model have shown very promising results on the ability of the model to capture correctly the complex dynamics of the area and at the same time to demonstrate the skill and robustness of the nesting technique applied.A second aim of this study is to prepare a comprehensive climatological surface boundary conditions data set for the Mediterranean Sea. This data set has been developed within the framework of the same research project and is suitable for use in ocean circulation models of the Mediterranean Sea or parts of it. The computation is based on the ECMWF 6-h atmospheric parameters for the period 1979-1993 and a calibrated set of momentum and heat flux bulk formulae resulted from previous studies for the Mediterranean region.

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Section: Circulation Patternsmentioning

confidence: 81%

Section: Nesting Techniquementioning

confidence: 88%

A one-way nested eddy resolving model of the Aegean and Levantine basins: implementation and climatological runs

2003

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“…The grid is used in order to get much higher resolution over the Sicily channel region ($5 km) than the surrounding areas ($12 -20 km). The internal Rossby radius of deformation is 10-12 km for the eastern Mediterranean [Robinson et al, 1991], in particular, from in situ density sections in the Sicily channel the Rossby radii for summer and winter are estimated as $16 km and $10 km, respectively, and since mesoscale eddies have a typical size a few times larger than this radius, the model in the highresolution area can resolve the mesoscale. The vertical structure is resolved by 25 sigma levels with logarithmic distribution near the surface to correctly simulate the dynamics of the surface layers.…”

Section: Model Grid and Bathymetrymentioning

confidence: 99%

Modeling the baroclinic circulation in the area of the Sicily channel: The role of stratification and energy diagnostics

Napolitano¹,

Sannino²,

Artale³

et al. 2003

J. Geophys. Res.

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[1] Aspects of the circulation of the Sicily channel region are studied with a highresolution, primitive equation, sigma coordinate model. This work is an attempt to study the process governing the purely baroclinic dynamics and its sensitivity to seasonal stratification, thus no atmospheric forcing is used. Two numerical experiments are analyzed using, as initial conditions, diagnostic velocity fields derived from the winter and summer climatological hydrologies. The quasi-steady state is characterized by circulation patterns, in the depth range of the Modified Atlantic Water (MAW) and the Levantine Intermediate Water (LIW), strongly controlled by mesoscale eddies and topography. Seasonal difference is found in the surface current which exhibits the major variability on the African side, downstream of Adventure Bank and the Ionian Slope where the absolute maximum occurs. The intermediate circulation instead does not show relevant seasonal differences. LIW enters through the two passages south of Malta Plateau and preferentially flows along the Sicilian shelf edge exiting over the northern sill. Its pathway is strongly controlled by subsurface cyclonic and anticyclonic cells. The results are in good agreement with observations. An energy diagnostics is applied to model results and sheds important light on dynamical characteristics of the mesoscale eddy field and indicates seasonal differences in the energetic exchange with the mean flow. The analysis of the mean (MKE) and eddy (EKE) kinetic energy, the transfer terms between energy compartments and the eddy momentum flux divergence indicates how eddies are strongly energetic in summer and exchange energy more efficiently with the mean flow. In the quasi-steady state MAW volume transport and MKE and EKE fluctuations are strongly correlated. This result suggests that mesoscale motions can control up to 40% of volume transport variability.INDEX TERMS: 4255 Oceanography: General: Numerical modeling; 4512 Oceanography: Physical: Currents; 4520 Oceanography: Physical: Eddies and mesoscale processes; KEYWORDS: Mediterranean, Sicily Strait, mesoscale, modeling Citation: Napolitano, E., G. Sannino, V. Artale, and S. Marullo, Modeling the baroclinic circulation in the area of the Sicily channel: The role of stratification and energy diagnostics,

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“…Three layers are defined as follows: L1, which includes 10 model levels from 5 to 240 m depth and roughly corresponds to the surface waters; L2, including 4 levels from 280 to 400 m and approximately corresponding to the Levantine Intermediate Water (LIW) layer (e.g. Robinson et al, 1991); L3, including 17 levels from 440 m to the sea bottom. OSSEs use the same GCM setup as the forecasting work and mainly focus on the whole Mediterranean basin; moreover, no regional optimization of the data assimilation parameters has been made.…”

Section: Methodsmentioning

confidence: 99%

“…The large-scale general circulation is composed of intense coastal/boundary currents and gyres with large seasonal and interannual variability (Millot, 1987;Robinson et al, 1991). The horizontal structure of the circulation is associated with vertical motions connected to the formation of deep and intermediate water masses.…”

Section: Introductionmentioning

confidence: 99%

Observing System Simulation Experiments for the assessment of temperature sampling strategies in the Mediterranean Sea

Raicich

Rampazzo

2003

Ann. Geophys.

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Abstract. For the first time in the Mediterranean Sea various temperature sampling strategies are studied and compared to each other by means of the Observing System Simulation Experiment technique. Their usefulness in the framework of the Mediterranean Forecasting System (MFS) is assessed by quantifying their impact in a Mediterranean General Circulation Model in numerical twin experiments via univariate data assimilation of temperature profiles in summer and winter conditions. Data assimilation is performed by means of the optimal interpolation algorithm implemented in the SOFA (System for Ocean Forecasting and Analysis) code.The sampling strategies studied here include various combinations of eXpendable BathyThermograph (XBT) profiles collected along Volunteer Observing Ship (VOS) tracks, Airborne XBTs (AXBTs) and sea surface temperatures. The actual sampling strategy adopted in the MFS Pilot Project during the Targeted Operational Period (TOP, winter-spring 2000) is also studied.The data impact is quantified by the error reduction relative to the free run. The most effective sampling strategies determine 25-40% error reduction, depending on the season, the geographic area and the depth range. A qualitative relationship can be recognized in terms of the spread of information from the data positions, between basin circulation features and spatial patterns of the error reduction fields, as a function of different spatial and seasonal characteristics of the dynamics. The largest error reductions are observed when samplings are characterized by extensive spatial coverages, as in the cases of AXBTs and the combination of XBTs and surface temperatures. The sampling strategy adopted during the TOP is characterized by little impact, as a consequence of a sampling frequency that is too low.

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The eastern Mediterranean general circulation: features, structure and variability

Cited by 209 publications

References 4 publications

A one-way nested eddy resolving model of the Aegean and Levantine basins: implementation and climatological runs

A one-way nested eddy resolving model of the Aegean and Levantine basins: implementation and climatological runs

Modeling the baroclinic circulation in the area of the Sicily channel: The role of stratification and energy diagnostics

Observing System Simulation Experiments for the assessment of temperature sampling strategies in the Mediterranean Sea

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