3 rd HyMeX workshop 1-4 June 2009, Heraklion, GREECE “ “ Extreme Extreme event impact on event impact on 3 3 - - D D thermohaline thermohaline structure structure variability in variability in the Aegean the Aegean - - Levantine Levantine region” region” Sarantis Sofianos Sarantis Sofianos Ocean Physics and Modelling group Ocean Physics and Modelling group University of Athens, Greece University of Athens, Greece
“Extreme event impact on 3 - D thermohaline structure variability in the Aegean - Levantine region” Sarantis Sofianos Ocean Physics and Modelling group University of Athens, Greece. 3 rd HyMeX workshop 1-4 June 2009 , Heraklion , GREECE. - PowerPoint PPT Presentation
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3rd HyMeX workshop 1-4 June 2009, Heraklion, GREECE
““ExtremeExtreme event impact on 3 event impact on 3--DD thermohaline structurethermohaline structure variability variability in the Aegeanin the Aegean--Levantine Levantine region”region”
Sarantis SofianosSarantis SofianosOcean Physics and Modelling groupOcean Physics and Modelling group
University of Athens, GreeceUniversity of Athens, Greece
• How robust is the thermohaline circulation pattern of the Eastern Mediterranean?
• What is the impact of long term (atmospheric and/or lateral) changes-variability on the thermohaline cells in the Eastern Mediterranean?
• How can extreme events alter the thermohaline circulation in the Aegean-Levantine region (and further downstream)?
• Combine data/models to evaluate the above.
Traditional SchemeTraditional Scheme
How typical is this scheme?How typical is this scheme?
Cretan Deep Waters (1000m)
Levantine Deep Waters (2000m)
S
S
EMTEMT
EMT SchemeEMT Scheme
Is this just a coincidence of forcing mechanisms or an indication Is this just a coincidence of forcing mechanisms or an indication of thermohaline cell sensitivity?of thermohaline cell sensitivity?
Cretan Deep Waters (1000m)
Levantine Deep Waters (2000m)
S
S
EMTEMT
??
Skliris, Sofianos, Lascaratos, JMS, 2007
Additional SchemeAdditional Scheme
What causes this type of variability?What causes this type of variability?
0.54 oC/cent
1.41 oC/cent
0.11 oC/cent
0.56 oC/cent0.49 oC/cent
0.83 oC/cent
1.41 oC/cent
0.54 oC/cent
0.90 oC/cent0.60 oC/cent
1880 1900 1920 1940 1960 1980 2000
18
19
20
SS
T(o C
)Mediterranean
Annual Mean SST
Filtered (5 years)
Trend=0.0041/y
1880 1900 1920 1940 1960 1980 2000
18
19
20
SS
T(o C
)
Mediterranean
Annual Mean SST
Filtered (10 years)
Trend=0.0041/y
Axaopoulos,MSc Thesis,Univ. Athens
Dominant period ~80 years
Long-term changesLong-term changes
Pre-conditioningPre-conditioning
Violent mixingViolent mixing
Sinking and spreadingSinking and spreading
… … communication with the rest of oceancommunication with the rest of ocean
D.W.F.PhasesD.W.F.Phases
Marshall and Schott, 1999
Effect of extreme Effect of extreme events (buoyancy events (buoyancy