Eastern Mediterranean Transient and reversal of the Ionian Sea circulation

Maps of the remotely sensed Absolute Dynamic Topography (ADT) and Sea Surface Temperature (SST) over the Eastern Mediterranean in the period June 1993 to June 2001 show a dramatic and sudden change in the sea surface structure. This change, which is presumably associated with the relaxation of the Eastern Mediterranean Transient (EMT), had taken place by the middle of 1997 and consisted of a complete reversal of the Ionian upper-layer circulation from anticyclonic to cyclonic. In the EMT phase, SST and ADT maps suggest enhanced communication between the Ionian and the Aegean basins as well as Aegean waters spreading northward along the eastern Ionian flank. Negative wind vorticity in the Ionian suggests that the switch of the upper-layer circulation from anticyclonic to cyclonic cannot be explained in terms of the wind forcing. Therefore, we suggest the predominance of the baroclinic vorticity production term in determining the upper-layer circulation inversion. Citation: Borzelli, G.L. E., M. Gacic, V. Cardin, and G. Civitarese (2009), Eastern Mediterranean Transient and reversal of the Ionian Sea circulation, Geophys. Res. Lett., 36, L15108, doi: 10.1029/2009GL039261.