Summary:
In the context of the present MSc Thesis the Eastern Mediterranean deep-water
variability during the last 60 years, in relation to new water mass sources, is
studied and analyzed using a comprehensive and most complete data set of
temperature and salinity profiles. The methodology used was based on time
series analysis and it leads to the conclusion that interannual to
multi-decadal variability is present in all sub-basins (Aegean, Adriatic,
Levantine, Ionian) with the Eastern Mediterranean Transient being the most
prominent event influencing the deep waters of the whole Eastern Mediterranean
in the last two decades, demonstrating the strong interaction between the
sub-basins. The changes that have occurred in the deep sea as a result of the
EMT event dwarf anything recorded in the observed history of the sea, and
illustrate how the long-term evolution of a seemingly stable circulation in a
complex environment can be dramatically changed by relatively small
perturbations. An additional objective of the thesis is to investigate the
variability of the thermohaline characteristics of the deep-water masses in the
Aegean Sea and in relation to the regional atmospheric forcing variability, by
comparing the available oceanographic and atmospheric datasets for the period
1960-2012. The analysis of the oceanographic and atmospheric dataset concludes
that during the examined period the variability of the deep water
characteristics of the basin is found to be very large. Due to its small size
and being a shelf sea, the Aegean Sea responds rapidly to the meteorological
changes and/or the variability of the lateral fluxes and this variability
propagates in the thermohaline characteristics of the deep water masses of the
basin through deep water formation processes. There are many episodes
characterized by a tight coupling of the atmosphere and the ocean during the
examined period, but the Eastern Mediterranean Transient (EMT) is the most
significant.