Abstract: Mesoscale eddies play an important role in energy transfer and material exchange in the ocean. Long-lived mesoscale eddies are frequently observed ocean processes at the shelf edge of the Black Sea. The researches about cross-shelf exchange are not enough, e.g., the seasonal characteristics of the exchange flux between shelf and basin induced by eddies, and the role of Rim Current in the cross-shelf exchange are not clear. Based on a three-dimensional circulation model output, combined with automatic eddies detection method, this study calculated cross-shelf exchange between the continental shelf and the deep sea in the northwestern Black Sea from 2002 to 2010. The contributions of Rim Current and eddies to the exchange process were comparatively investigated. The correlation coefficients between the intensities of Rim Current in the northwestern Black Sea region and the inward and outward transport across the continental shelf are 0.57 and 0.67 respectively, and the correlation coefficient between the Rim Current location and the cross-shelf exchange capacity is 0.52. Seasonal changes in intensity and location of the Rim Current lead to seasonal variations in the cross-shelf flux in the northwestern Black Sea. Eddies-induced cross-shelf exchange accounts for about 16% to 31% of the total cross-shelf exchange during March to August, in this research seasonality of cross-shelf flux has been confirmed. Even a single eddy is able to influence significantly the flux in the northwestern Black Sea. About volume of northwestern-shelf water was renewed by a single mesoscale eddy over the period 5 May to 20 July 2005, which is equivalent to 30.9% of the overall volume of shelf water.

Key words: cross-shelf exchange, Rim Current, eddy