The role of meso- and submesoscale processes for the near coastal oxygen supply into the oxygen minimum zone off Peru

Thomsen, Sören, Kanzow, Torsten and Krahmann, Gerd (2013) The role of meso- and submesoscale processes for the near coastal oxygen supply into the oxygen minimum zone off Peru [Talk] In: Warnemünde Turbulence Days 2013, 13.08.2013, Vilm, Germany.

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At the submesocale a strong physical-biogeochemical coupling exists due to similar temporal and spatial scales of the physical and biogeochemical processes involved. A swarm experiment with seven gliders equiped with biophysical sensors measuring pressure, temperature, salinity, oxygen, chlorophyll fluorescence and turbidity was conducted in early 2013 in the upwelling region off Peru. The goal of the experiment was to sample a relatively small spatial area as synoptically as possible, in order to allow seperation between temporal and spatial variability. In particular, the role of submesoscale processes for the near coastal vertical oxygen distribution was assessed. Each glider carried out about one dive per hour measuring two multi-parameter profiles with a lateral resolution of about 500 m. Alltogether more than 15.000 profiles were recorded during the two-months deployment.

The glider data shows small scale filamentary structures of different tracers such as salinity and oxygen at different depths. There are density compensated salinity filaments at about 150 m depth were lateral mesoscale eddy stirring of the lateral background salinity gradient is suggested as the main formation mechasim. Closer to the surface, however, non-density compensated salinity and oxygen intrusions reaching well below the mixed layer can be seen. These structures are found at strong lateral mixed layer density fronts, suggesting that submesoscale frontal processes are responsible for the observed structures. This findings suggest that beside diapycnal mixing vertical velocities due to submesoscale frontal processes lead to an additional oxygen supply from the oxygenated mixed layer into the oxygen minimum zone.

Document Type: Conference or Workshop Item (Talk)
Research affiliation: OceanRep > SFB 754 > B9
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-PO Physical Oceanography
OceanRep > SFB 754
Projects: SFB754
Date Deposited: 18 Oct 2013 09:45
Last Modified: 22 Oct 2013 12:52

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