engleski

Dense water generation in the North Adriatic Sea: the spreading towards the Middle and South Adriatic

The paper describes thermohaline properties in the North and Middle Adriatic in 1998 and 1999, on the basis of temperature and salinity data collected at Po-Rovinj, Jabuka Pit and Palagruža Sill profiles. Enhanced heat losses and low Po River discharge resulted in North Adriatic Dense Water (NAdDW) generation in winter 1999, while weak air-sea exchange in winter 1998, in addition to moderate Po River discharge rates, induced presence of very fresh water in the whole North Adriatic and consequently no NAdDW generation. Preconditioning, generation and spreading of NAdDW has been analysed in details. After the generation NAdDW flowed as a dense current towards the Jabuka Pit along the western Adriatic slope. Its densest core interacted with the topography and rapidly sank when reaching relatively steep slope west from the Jabuka Pit. The second part followed the slope as a dense current but not interacting with the bottom, detouring the pit from its southeastern side and hitting the bottom somewhere on the eastern segment of the pit. The detouring of dense current has been successfully reproduced by analytical two-layered model of dense current over a slope, and dense current velocity has been estimated to be up to 20 cm/s for the strongest NAdDW generations. Finally, the lightest part of NAdDW current followed the western slope, entering the South Adriatic Pit and contributing to the water mass kinematics and dynamics there. In addition, the leakage of NAdDW can be found in the very bottom of the middle parts of Palagruža Sill, but with rates significantly smaller compared to the NAdDW current that flow over the western slope.

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