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www.ocean-sci-discuss.net/6/525/2009/
doi:10.5194/osd-6-525-2009
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Surface circulation in the Eastern Mediterranean using drifters (2005–2007)
1Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS) – Borgo Grotta Gigante, 42/c-34010 Sgonico (Trieste), Italy
2Université de la Méditerranée, CNRS UMR 6535, Laboratoire d'Océanographie et de Biogéochimie (LOB), Antenne de Toulon, BP 330, 83507 La Seyne, France
3Institut National des Sciences et Technologie de la Mer (INSTM) – 28, rue du 2 mars 1934 2025 Salammbô, Tunisia
Abstract. Within the framework of the EGITTO/EGYPT program, the spatial structure and the temporal variability of the surface circulation in the eastern basin of the Mediterranean Sea was studied by means of satellite-tracked drifters. A total of 97 drifters drogued to 15-m nominal depth were released between September 2005 and March 2007, either regularly along ship-of-opportunity routes (Sicily Channel) or within specific structures during dedicated campaigns (Levantine sub-basin). After editing and low-pass filtering, the drifter trajectories were used to estimate pseudo-Eulerian statistics: mean current, variance ellipses, mean and eddy kinetic energies. A statistical analysis was also performed dividing the dataset in two extended seasons (winter and summer). This study completes previous ones in the Sicily Channel and in the Ionian. Several veins are evidenced, together with a seasonal variability inducing a reversal of the circulation in the southern part of the Ionian. However, in this latter area, data are too scarce and the dynamics too complex to achieve a circulation pattern yet. Eastward, the general circulation is described as a counterclockwise flow along the Libyo-Egyptian and Middle East slopes. Part of this flow is deflected toward the open sea by the anticyclones generated alongslope by the Libyo-Egyptian current (Libyan and Egyptian eddies), by the wind (Ierapetra) or by the topography (over the Eratosthenes Seamount and off Latakia). The entrainment of this flow around successive eddies (paddle-wheels effect) results in an open sea eastward transport of Atlantic water. When the Libyan eddies (anticyclonic) are close to the slope, the westward current is stronger than the mean eastward current and the circulation is temporally and locally reversed. The strong variability induced by the eddies and the meteorological conditions hinder evenly covering all the study area. Additional deployments are required to improve further our understanding of the circulation in this basin.
Discussion Paper (PDF, 4190 KB) Interactive Discussion (Closed, 4 Comments) Final Revised Paper (OS)
Notice on Discussion StatusCitation: Gerin, R., Poulain, P.-M., Taupier-Letage, I., Millot, C., Ben Ismail, S., and Sammari, C.: Surface circulation in the Eastern Mediterranean using drifters (2005–2007), Ocean Sci. Discuss., 6, 525-555, doi:10.5194/osd-6-525-2009, 2009. Bibtex EndNote Reference Manager XML
