The surface circulation in the eastern basin of the Mediterranean Sea

Hamad, N.; Millot, Claude; Taupier‐Letage, Isabelle

doi:10.3989/scimar.2006.70n3457

Cited by 92 publications

(29 citation statements)

References 65 publications

(137 reference statements)

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“…The EGYPT‐1 campaign was held in April 2006 within the frame of the EGYPT (Eddies and GYres Paths Tracking) and EGITTO observational programs to study the role of the mesoscale eddies on the general circulation in the Eastern Basin (Taupier‐Letage et al, ). Among the 125 CTD casts performed, one section crossed the Ierapetra eddy generated in 2005 (Taupier‐Letage, ), with 18 CTD profiles every 8–10 km along a total distance of 180 km.…”

Section: Methodsmentioning

confidence: 99%

“…This large anticyclone that drift westward was identified as a Libyo‐Egyptian eddy by previous studies (Gerin et al, ; Mkhinini et al, ; Sutyrin et al, ; Taupier‐Letage, ). Several surface drifters, trapped inside the eddy from May to September 2006, and a full CTD transect, performed in May 2006 (Taupier‐Letage et al, ), quantify the horizontal velocity and the vertical structure of this surface‐intensified anticyclone (Sutyrin et al, ) but no connection was made with the Ierapetra eddy formed in 2004. To make such link, a complete reconstruction of the eddy trajectory that takes into account the merging with other structures should be done.…”

Section: Lifetime Of the Ierapetra Anticyclonementioning

confidence: 99%

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Dynamical Evolution of Intense Ierapetra Eddies on a 22 Year Long Period

Ioannou

Stegner

et al. 2017

JGR Oceans

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Considered as wind forced, the recurrent formation of Ierapetra eddy affects the Eastern Mediterranean Sea circulation. Even though this large, coherent, and long‐lived anticyclone has been extensively studied, there are only few quantitative information on its dynamical characteristics. The main goal of this study is to quantify the Ierapetra eddies (IEs) intensity and examine their seasonal and interannual variability over a 22 year period (1993–2014). We choose the automatic eddy detection algorithm AMEDA to estimate the main IEs dynamical parameters such as their size, their intensities, and their lifetimes. Applied to daily AVISO altimetric products, the AMEDA allows a full eddy characterization providing additional information on vortex velocity profiles as well as on merging and splitting events. Among the years of observations, the IEs Rossby number experience a strong variability and could vary by a factor 4 (Ro = 0.07–0.27). This is mainly due to the eddy velocity variations rather than size variations. Moreover, we found that after their formation IEs could reintensify. This intensification process may lead to a doubling of the vortex intensity in less than 4 months. That extra input of energy coincides with the Etesian winds period. Such high intensities are not expected from large‐scale anticyclones and require cyclogeostrophic corrections. Considering this ageostrophic part, the maximum values of the core vorticity were derived and we found that the IEs might sometimes exhibit a negative potential vorticity core. Evidences on the eddy intensity from two oceanographic campaigns suggest that the IEs are probably more intense than we even estimate.

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Section: Methodsmentioning

confidence: 99%

Section: Lifetime Of the Ierapetra Anticyclonementioning

confidence: 99%

Dynamical Evolution of Intense Ierapetra Eddies on a 22 Year Long Period

Ioannou

Stegner

et al. 2017

JGR Oceans

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“…In a similar way, the complex orography of Crete island acts as an obstacle for the wind propagation inducing channeling and deflection of the Etesian winds that impact the regional circulation in the south Aegean Sea and the Levantine basin. This study focuses on this specific area where intense coastal anticyclones are formed recurrently during the summer months (Larnicol et al, 1995;Matteoda and Glenn, 1996;Hamad et al, 2005Hamad et al, , 2006Taupier-Letage, 2008;Amitai et al, 2010;Menna et al, 2012;Mkhinini et al, 2014;Ioannou et al, 2017). Kotroni et al (2001) performed simulations with and without Crete and they concluded that the Crete mountain ranges (three mountains in the row with height around 2, 000 m in Figure 1A) modify the Etesian intensity and pathways.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Evolution of Mesoscale Anticyclones in the Lee of Crete

et al. 2020

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Motivated by the recurrent formation of mesoscale anticyclones in the southeast of Crete, we investigated with a high resolution model the response of the ocean to orographic wind jets driven by the Cretean mountain range. As shown in the dynamical process study of Ioannou et al. (2020) which uses a simplified shallow-water model, we confirm here, using the CROCO (Coastal and Regional Ocean COmmunity) model, that the main oceanic response to the Etesian wind forcing is the formation of mesoscale anticyclones. Moreover, we found that the intensity of the wind-induced Ekman pumping acting on the eddies, once they are formed, modulates their intensity. Among the various coastal anticyclones formed during summer and fall 2015, only one of them will correspond to a long lived structure (M_IE15) which is similar to the Ierapetra Eddy detected in 2015 (O_IE15) on the AVISO/DUACS products. Thanks to the DYNED-Atlas data base, we were able to perform a quantitative comparison of the vertical structure of such long-lived anticyclone between the numerical model and the in-situ measurements of the various Argo profilers trapped inside the eddy core. Even without assimilation or any nudging, the numerical model was able to reproduce correctly the formation period, the seasonal evolution and the vertical structure of the O_IE15. The main discrepancy between the model and the altimetry observations is the dynamical intensity of the anticyclone. The characteristic eddy velocity derived from the AVISO/DUACS product for the O_IE15 is much lower than in the numerical model. This is probably due to the spatio temporal interpolation of the AVISO/DUACS altimetry products. More surprisingly, several coastal anticyclones were also formed in the model in the lee of Crete area during summer 2015 when the Etesian winds reach strong values. However, these coastal anticyclones respond differently to the wind forcing since they remain close to the coast, in shallow-waters, unlike the M_IE15 which propagates offshore in deep water. The impact of the bottom friction or the coastal dissipation seems to limit the wind amplification of these coastal anticyclones.

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“…The southern continental slopes of western and eastern basins are characterised by narrow and unstable currents located respectively in the Algerian (Algerian Current) and Levantine (Libyo-Egyptian Current) sub-basins, that flow from west to east and lead to the generation of cyclonic and anticyclonic eddies (Mejdoub and Millot., 1995;Hamad et al, 2005;Taupier-Letage et al, 2007;Gerin et al, 2009). These currents extend as deep as the LIW core depth (200-500 m).…”

Section: Background On the Mediterranean Intermediate Circulationmentioning

confidence: 99%

Mediterranean intermediate circulation estimated from Argo data in 2003–2010

Menna

Poulain

2010

Ocean Sci.

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Abstract. Data from 38 Argo profiling floats are used to describe the intermediate Mediterranean currents for the period October 2003-January 2010. These floats were programmed to execute 5-day cycles, to drift at a neutral parking depth of 350 m and measure temperature and salinity profiles from either 700 or 2000 m up to the surface. At the end of each cycle the floats remained at the sea surface for about 6 h, enough time to be localised and transmit the data to the Argos satellite system. The Argos positions were used to determine the float surface and intermediate displacements.At the surface, the float motion was approximated by a linear displacement and inertial motion. Intermediate velocities estimates were used to investigate the Mediterranean circulation at 350 m, to compute the pseudo-Eulerian statistics and to study the influence of bathymetry on the intermediate currents. Maximum speeds, as large as 33 cm/s, were found northeast of the Balearic Islands (western basin) and in the Ierapetra eddy (eastern basin). Typical speeds in the main along-slope currents (Liguro-Provençal-Catalan, Algerian and Libyo-Egyptian Currents) were ∼20 cm/s. In the central and western part of Mediterranean basin, the pseudo-Eulerian statistics show typical intermediate circulation pathways which can be related to the motion of Levantine Intermediate Water. In general our results agree with the qualitative intermediate circulation schemes proposed in the literature, except in the southern Ionian where we found westward-flowing intermediate currents. Fluctuating currents appeared to be usually larger than the mean flow. Intermediate currents were found to be essentially parallel to the isobaths over most of the areas characterized by strong bathymetry gradients, in particular, in the vicinity of the continental slopes.

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The surface circulation in the eastern basin of the Mediterranean Sea

Cited by 92 publications

References 65 publications

Dynamical Evolution of Intense Ierapetra Eddies on a 22 Year Long Period

Dynamical Evolution of Intense Ierapetra Eddies on a 22 Year Long Period

Three-Dimensional Evolution of Mesoscale Anticyclones in the Lee of Crete

Mediterranean intermediate circulation estimated from Argo data in 2003–2010

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