Μαθηματική προσομοίωση και διερεύνηση με τη χρήση υβριδικού ομοιώματος της επίδρασης των νερών της Μαύρης Θάλασσας στη δυναμική των θαλασσίων μαζών του Βορείου Αιγαίου

Abstract

The brackish Black Sea Waters (BSW) outflow to the Aegean Sea, through the Dardanelles Straits, affects and determines significantly the hydrodynamic and physical characteristics of the North Aegean Sea. The investigation and mathematical simulation of the N. Aegean’s physical oceanography contributes to the knowledge and understanding of the buoyant waters’ circulation initial conditions in the wider East Mediterranean region. The implementation and adaptation of the 3-d hydrodynamic mathematical model HYCOM (Hybrid Coordinate Ocean Model) in the N. Aegean Sea (NAS-HYCOM, North Aegean Sea – HYCOM, 1/50οx1/50o), undertaken for the first time, significantly contributes to the investigation of the area’s hydrodynamic circulation. The significant potentials of HYCOM are related to the hybrid vertical coordinate operation. Simultaneously, a parameterization of the Dardanelles 2 layer-flow, based on the Black Sea water budget, is implemented at the Dardanelles Strait, in order to calculate the transport rates and the physical characteristics of the buoyant outflow. Evaluation of the innovative parameterization approach showed that it presents high correlation between model results and satellite and insitu data. Several idealized (process oriented approach) and realistic (covering the period 2002-2008) numerical experiments were performed. The major hydrodynamic features and their relation with several controlling factors are investigated in the context of the thesis. The buoyant plume tracks are also controlled by specific characteristics of the area’s complicated topography. NAS-HYCOM simulations showed that both north and south winds tend to prevent the BSW cyclonic circulation along the continental shelf. The evolution of the anticyclonic bulge radius in front of the Dardanelles exit is investigated numerically, with NAS-HYCOM, as well as analytically, by the implementation of a theoretical model for large scale river plumes. Additionally, the surface mixed layer and the dense water formation in the area covered with brackish waters was also investigated. Brackish surface waters decrease the buoyancy loss and seem to play a suppressive role to the development of both of these formations, especially in areas close to the Dardanelles. Conclusively, it is observed that the BSW affect all the major physical processes in the N. Aegean Sea, which present strong seasonal and interannual variability, highly related to the respective variations of the Dardanelles outflow characteristics. NAS-HYCOM has been successfully applied to the complicated N. Aegean area and its adaptation constitutes an important tool on the description and understanding of the BSW influence to the region’s dynamics. It is, further, concluded that HYCOM, used in the past mostly in larger scale applications, can reliably simulate the physical oceanography conditions of semi-closed coastal areas.%%%%Η eκροή των υφάλμυρων νeρών της Μαύρης Θάλασσας (ΝΜΘ) στο Βόρeιο Αιγαίο, διαμέσου των Στeνών των Δαρδανeλίων, eπηρeάζeι και καθορίζeι τα υδροδυναμικά και…