Synoptic variability in the Black Sea. Analysis of hydrographic survey and altimeter data

Mesoscale features in the Black Sea circulation obtained from fine resolution hydrographic survey data and TOPEX/Poseidon (T/P) altimeter are compared. Important scales, associated with pronounced eddy variability and diapycnal exchange at the depth of redox-zone, which are well resolved in the hydrographic survey data, are not sufficiently resolved in the altimeter data. However, the satellite data give clear signals associated with the variability of general circulation, as well as with the dynamics of larger eddies. The seasonal transitions in the circulation between the intense winter–spring state and the less intense summer–fall state is also well resolved. The propagation patterns of oscillations along the eastern coast detected from satellite altimetry support earlier concepts based on direct observations in this region. The correlation between two data types reveals the value of altimeter-derived signals as representative data source for describing the temporal changes of mesoscale ocean dynamics. Some estimates about the possible use of altimeter data for assimilation in numerical models are provided.