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Isabel Ambar and Nuno Serra Instituto de Oceanografia

WORKSHOP Deep Ocean Exchange with the Shelf Cape Town, 6-8 October 2008 The role of deep eddies in offshore transfers. Isabel Ambar and Nuno Serra Instituto de Oceanografia Faculdade de Ciências, Universidade de Lisboa. SST (11 July 2002).

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Isabel Ambar and Nuno Serra Instituto de Oceanografia

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  1. WORKSHOPDeep Ocean Exchange with the ShelfCape Town, 6-8 October 2008The role of deep eddies in offshore transfers Isabel Ambarand Nuno Serra Instituto de Oceanografia Faculdade de Ciências, Universidade de Lisboa

  2. SST (11 July 2002) Surface filaments and eddies are known as key factors in the transfer processes of mass, heat and momentum between shelf and deep ocean regions. Chlorophyll pigments (11 July 2002)

  3. Question Do sub-surface eddies, like those detaching from the Mediterranean Undercurrent off Iberia – the meddies - play a role in the transfers from shelf to deep ocean ? Richardson, 2000

  4. Meddies are Mediterranean Water lens-like coherent structures, existing at depths from 600 to 1400 m, in solid body anticyclonic rotation, with typical diameters of about 50 – 100 km. 600 m 800 m 1400 m 50 – 100 km

  5. Floats launched during MEDTOP

  6. Eddy generation at Estremadura Promontory (23 April 2001 - 18 April 2002)

  7. AMUSE meddies (1993-1995) CANIGO meddies (1997-1999) MEDTOP meddies (2001-2003) float depths: 500 m 800 m 1200 m

  8. In the last decade, field observations off the southern coast of Iberia were able to detect the presence of cyclones associated with meddies to form vortex pairs - dipoles - at the level of the Mediterranean Water. meddy cyclone Serra et al. (2002) Generation at Cape St. Vincent dipole dipole Generation at the Portimão Canyon region Serra and Ambar (2002)

  9. These cyclones play a role on the detachment of the meddies from the Mediterranean Undercurrent and seem to be fundamental for the translation of meddies away from their generation zone. Eddy generation at Cape St. Vincent Cape St Vincent promotes the overshoot and separation of the MW Undercurrent Advection or anticyclone-cyclone coupling provides detachment Serra, Ambar and Käse (2005)

  10. Eddy generation at the Portimão Canyon region Stretching of the MW layer at the Portimao Canyon induces cyclonic vorticity Cyclone extracts MW from the slope -> dipole ejection Serra, Ambar and Käse (2005)

  11. Oliveira, Serra, Ambar & Fiúza (2000) The dynamical fields associated with the meddies and cyclones extend vertically much farther than the depth range where the thermohaline anomaly is detected, and may reach levels down to 3000 m or up to the sea surface.

  12. 25 May 2001 18 June 2001 Dipole followed by remote sensing (sea surface temperature) and by RAFOS MEDTOP project

  13. SST 12 Jun 98 – 14 Sep 98 Chlorophyll pigments concentration Data received and processed at IOFCUL 17 Jun 98 Serra, Boutov and Ambar (to be submitted)

  14. Salinity + velocity normal to the section Cyclones Anticyclones Vertical structure of the model dipoles

  15. model SST (°C) model MW thickness (m) Serra, 2008

  16. surface temperature and velocity salinity and velocity at 1200 m Serra, 2008

  17. THANK YOU

  18. In situ Chl-a Model SST Serra, 2008

  19. SST Chlorophyll pigments concentration 6 Jun 01 1 Apr 01 – 5 Aug 01 Serra, Boutov and Ambar (to be submitted)

  20. Deep-Sea Research II 52 (2005) 383–408 Observations and numerical modelling of the Mediterranean outflow splitting and eddy generation Nuno Serra, Isabel Ambar, Rolf Kaese Journal of Marine Systems 71 (2008) 195–220 Observations of the Mediterranean Undercurrent and eddies in the Gulf of Cadiz during 2001 I. Ambar, N. Serra, F. Neves, T. Ferreira

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