Modelling subsurface dynamics in the Black Sea

Dependency of major hydrophysical/chemical features of highly stratified basins on density surfaces in the vertical makes isopycnic models an attractive tool for simulating the dynamics of marginal marine environments such as the Black Sea because of the ability of these models to restrict vertical transport to some desirable degree. In the present work the seasonal variations of the subsurface dynamics of the Black Sea are investigated using an isopycnic model. Particular attention is given to the interfaces of the Cold intermediate layer and Suboxic layer and finally, the deep layer circulation in the basin is studied. It appears that although the depth range of the base of the Cold intermediate layer and the lower Soboxic layer interface do not change seasonally, their horizontal distribution is defined by the upper layer dynamics of the basin. Cyclonic surface circulation diminishes with increasing depth and the deep layer circulation is characterised by an anti-cyclonic rim current driven by density gradients created from river runoff and the influx of Mediterranean water.