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3 rd HyMeX workshop 1-4 June 2009 , Heraklion , 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.

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3 rd HyMeX workshop 1-4 June 2009 , Heraklion , GREECE

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  1. “Extreme event impact on 3-Dthermohaline structurevariability in the Aegean-Levantine region” Sarantis Sofianos Ocean Physics and Modelling group University of Athens, Greece 3rd HyMeX workshop 1-4 June 2009, Heraklion, GREECE

  2. 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.

  3. Traditional Scheme How typical is this scheme?

  4. Levantine Deep Waters (2000m) Cretan Deep Waters (1000m) EMT

  5. EMT Scheme Is this just a coincidence of forcing mechanisms or an indication of thermohaline cell sensitivity?

  6. Levantine Deep Waters (2000m) Cretan Deep Waters (1000m) EMT ?

  7. Skliris, Sofianos, Lascaratos, JMS, 2007

  8. Additional Scheme What causes this type of variability?

  9. 1.41oC/cent 0.54 oC/cent 0.83 oC/cent 1.41 oC/cent 0.90 oC/cent 0.11 oC/cent 0.54 oC/cent 0.60 oC/cent 0.56 oC/cent 0.49 oC/cent Long-term changes Dominant period ~80 years Axaopoulos,MSc Thesis,Univ. Athens

  10. Pre-conditioning Effect of extreme events (buoyancy loss rate) Violent mixing Sinking and spreading D.W.F.Phases … communication with the rest of ocean Marshall and Schott, 1999

  11. Η ,r = 80km H = 1000 m y = 440km x = 440km Compare 1-D approach with 3-D results (1000 W/m2) Forcing rates: 100 W/m2 250 W/m2 500 W/m2 750 W/m2 1000 W/m2 1250 W/m2 1500 W/m2 2000 W/m2 Resolution: 0.04ox0.04o (4,4 x 4,4 km) Krokos, MSc Thesis, Univ. Athens

  12. 5days 10 days 15 days 20 days 25 days 5days 10 days 15 days 20 days 25 days

  13. Effect of buoyancy loss rate The rate of buoyancy loss is very important in determining the final characteristics of the water mass formed

  14. Vervatis, Sofianos and Theocharis, 2009

  15. ARPERA (~1o/10) Extreme Events 1960-2001+ ALERMO (~1o/30) OPAMED8

  16. How robust is the thermohaline circulation pattern of the Eastern Mediterranean? • Less than we thought • What is the impact of long term (atmospheric and/or lateral) changes-variability on the thermohaline cells in the Eastern Mediterranean? • ▪ Changes the preconditioning • ▪ Induces different behavior of extreme events • How can extreme events alter the thermohaline circulation in the Aegean-Levantine region (and further downstream)? • Crucial in determining the thermohaline cell structure • Combine data/models to evaluate the above: Beyond the idealized approach Thank you!

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