DATE2016-05-31 13:31:03
IDABSTRACT20160531133103-1018
CONTACTsampatakaki@aegean.gr
PRESENTATIONPOSTER
INVITED0
IDSESSION3
TITLEMEDITERRANEAN SEA CIRCULATION DURING YOUNGER DRYAS AND S1A SAPROPEL DEPOSITION INTERVALS: A NUMERICAL APPROACH
AUTHORSAngeliki Sampatakaki (1), Vassilis Zervakis (1), Alexandra Gogou (2), Maria Triantaphyllou (3), Nikolaos Skliris (4)
AFFILIATIONS
  1. Department Of Marine Sciences, University Of The Aegean, Mytilene (Greece)
  2. Hellenic Centre For Marine Research, Institute Of Oceanography, Anavyssos (Greece)
  3. Faculty Of Geology And Geoenvironment, National And Kapodistrian University Of Athens, Athens (Greece)
  4. National Oceanography Centre, University Of Southampton, Southampton (United Kingdom)
ABSTRACTThe Mediterranean Sea has experienced different climatic conditions during the past geological periods, and as a result its thermohaline circulation varied accordingly. This study presents potential circulation patterns of the Mediterranean Sea during the Younger Dryas and the S1a sapropel deposition intervals, produced by numerical simulations using an Oceanic General Circulation Model. Radiative forcing varied based on orbital reconstructions, providing different insolation values for each period. The reproduction of paleo air-sea fluxes was based on marine cores' reconstructed data. The model was permitted to drift freely till convergence to reconstructed sea-surface values, and the arising diagnosed fluxes were used. The Black Sea was assumed to be still separated from the Mediterranean. The model results exhibit considerable agreement with the marine cores' reconstructed data; the assessment is based on the sea temperature and salinity spatial gradients. The outputs showed different density vertical profiles between the experiments, a fact revealing different circulation patterns. Our simulations suggest that during Younger Dryas, the Mediterranean Sea, characterized by low temperatures and high salinities, was a well-mixed concentration basin, with low stratification throughout the water column. The water residence time in the eastern basin was calculated to a few decades. Under the wet and warm conditions of S1a sapropel deposition, the Eastern Mediterranean exhibited strongly stratified vertical profiles, especially in the Ionian and Levantine basins, with the sea circulation being limited to the upper layers. During that period the intermediate and deep waters' density of eastern basin was lower than the western. The Eastern Mediterranean Sea was characterized by a thermohaline circulation of an "opposite" phase to the modern one, i.e. behaving as a dilution sub-basin. Its water residence time was calculated to be higher than three hundred years.
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