Aegean surface circulation from a satellite-tracked drifter array

Donald Olson, Vassiliki H Kourafalou, William E Johns, Geoff Samuels, Milena Veneziani

Research output: Contribution to journalArticle

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Abstract

A pilot experiment using an array of 45 drifters to explore the circulation in the north and central Aegean Sea is described. The global positioning system drifters with holey-sock drogues provide positions every hour with data recovery through the Argos system. The drifters were launched in four separate deployments over a 1-yr period. The resulting trajectories confirm the existence of a current around the rim of the basin consistent with a buoyancy plume created by the outflow of Black Sea waters through the Dardanelles (Strait of Çanakkale in Turkish). The degree to which this is augmented by an Ekman response to the dominant northerly winds is not obvious in the dataset owing to mesoscale dynamics that obscure the existence of any westward Ekman flow. The mesoscale eddy field involves anticylonic eddies in the current around the rim of the basin consistent with eddies with low-salinity-water cores. Cyclones are also seen, with the most prominent forming over deep regions in the basin topography. The array also documents the interaction of the currents with the straits through the Sporades and Cyclades island groups. These inter-actions are complicated by the nature of the mesoscale flow and in some trajectories suggest a Bernouilli acceleration in straits; in others the flow through the island groups appears to be more diffusive and involves deceleration and eddy motions. The rapid sampling by the drifters reveals an extremely nonlinear submesoscale eddy field in the basin with length scales less than 4 km and Rossby numbers of order 1. A better understanding of the dynamics of these features is of importance for understanding the circulation of the basin.

Original languageEnglish (US)
Pages (from-to)1898-1917
Number of pages20
JournalJ. PHYSICAL OCEANOGRAPHY
Volume37
Issue number7
DOIs
StatePublished - Jul 2007

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drifter
eddy
strait
basin
trajectory
Rossby number
Argo
mesoscale eddy
cyclone
buoyancy
outflow
GPS
plume
topography
seawater
sampling
experiment

ASJC Scopus subject areas

  • Oceanography

Cite this

Aegean surface circulation from a satellite-tracked drifter array. / Olson, Donald; Kourafalou, Vassiliki H; Johns, William E; Samuels, Geoff; Veneziani, Milena.

In: J. PHYSICAL OCEANOGRAPHY, Vol. 37, No. 7, 07.2007, p. 1898-1917.

Research output: Contribution to journalArticle

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