Water mass properties and dynamic conditions of the Eastern Mediterranean in June 2007

Five locations in the Eastern Mediterranean, situated in the Ionian Sea, Cretan passage and Levantine basin, were characterized for their physical and biogeochemical properties on the basis of the data collected during an oceanographic cruise in June 2007. Basinwide, subbasin and mesoscale surface dynamic features are described in terms of absolute dynamic topography of the sea surface, sea surface temperature and chlorophyll-a distribution. Additional information along the ship’s track was acquired via the vessel-mounted thermosalinograph and the Acoustic Doppler Current Profiler, providing data on temperature, salinity and marine current. The latter helped identify the depth penetration (<300 m) of some dynamic structures revealed by satellite imagery. The principal water mass characteristics of the Eastern Mediterranean are described in terms of thermohaline properties and inorganic nutrient concentrations. Mixing of the principal water masses at each location was estimated by means of optimum multiparameter analysis. The June 2007 thermohaline properties are compared with those from previous studies that have described the evolution of the Eastern Mediterranean Transient from the early 1990s through the early 2000s. The processes of horizontal and vertical mixing that tend to decrease temperature and salinity of the deep waters with respect to the maximum reached during or some time after the Eastern Mediterranean Transient seem still to persist in 2007.

► Thermohaline properties in the Eastern Mediterranean during June 2007 are described. ► Surface dynamic structures, sea temperature and chlorophyll-a are mapped. ► Subsurface flow is portrayed using the VM-ADCP currents, drifter and float trajectories. ► Quantitative mixing of the main water masses is achieved by the optimum multiparameter analysis. ► Deep temperature and salinity are put in the context of the post – East Mediterranean Transient.