CIRCULATION IN THE SURFACE AND INTERMEDIATE LAYERS OF THE BLACK-SEA

Circulation features of the Black Sea are presented based upon a basin -scale survey carried out in September-October 1990. The circulation p attern for the upper 300-400 dbar consists of a cyclonically meanderin g Rim Current, a series of anticyclonic eddies confined between the co ast and the Rim Current, and a basin-wide, multi-centered cyclonic cel l in the interior of the basin. In contrast to prior investigations, a lthough the currents are much weaker as compared with those in the upp er layer, the intermediate depth (defined here between 500 and 1000 db ar) circulations reveal considerable structural variability. This invo lves counter-currents, shift of eddy centers, coalescence of eddies, a nd associated sub-basin-scale recirculation cells separated by the mea ndering Mid-Basin Current system. A descriptive synthesis of the upper layer circulation, combining the present results with earlier finding s, identifies the quasi-permanent and recurrent features even though t he shape, position, strength of eddies and meander pattern, and the bi furcation structure of currents vary.