4. Black Sea

4.1. Satellite data

The Black Sea as a whole basin was divided into eight sub-regions [27]. Six of them (#1-5 and #8) lie in the shelf area (depth less than 200 m), the sub-regions #6 and #7 are deep open parts of the basin (Fig. 14). Six regions in the shelf area were considered separately because they were distinguished with respect to their position, bathymetry and influence of river run-off. Regions #1-3 have depth of less than 50 m; region #1 is under strong influence of water discharge of the Dnepr, Dnestr and Bug rivers, whereas region #2 is influenced mainly by the Danube river. Regions #4 and 5 are the northern and southern outer shelf regions (depth of 50-200 m) of the western part of the Black Sea; the southern, eastern and northeastern shelf regions of the eastern part of the basin were combined and evaluated as a single region (#8).

The general circulation of the Black Sea consists of the strong Rim Current [28] following the narrow continental slope; the Rim Current limits the water and material transfer from coastal zone to the open Black Sea. The interior of the Rim Current zone is formed by two cyclonic cells occupying the western and eastern halves of the basin; for this reason the western (#6) and eastern (#7) open parts of the Black Sea were considered separately.

Fig.15 shows a monthly coverages of the sub-regions of the Black by satellite data from SeaWiFS and MODIS-Aqua given by different hatching.