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| Titel |
Estimate of Diapycnal Mixing from eight Hydrographic Surveys in the Subpolar North Atlantic |
| VerfasserIn |
Mingming Li, Christian Mertens, Maren Walter, Monika Rhein |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048545
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| Zusammenfassung |
| The transformation of water masses in the subpolar North Atlantic is essential to maintain the
oceanic stratification and support the Atlantic Meridiornal Overturning Circulation. Previous
studies based on finestructure observations yield mean diapycnal diffusivity KÏ of the order
10-5 m2s-1, which is an order of magnitude less than the theoretical value suggested by
Munk in 1966.
In the area between 42Ë and 62Ë N deep water formation provides dense abyssal water
masses, which are part of the global overturning circulation. Eight cross-Atlantic large-scale
hydrographic surveys were carried out during the years 2003-2010 with combined
CTD/LADCP measurements.
Turbulent diffusivity KÏ is estimated from the energy dissipation rate, which is inferred
from parameterisation of velocity and strain of the density field. Observational data are
analysed to get an overview of the regional variability in the strength of the mixing
and to identify the dependencies of KÏ in this area. The analysis of RV Meteor
cruise M59/2 carried out in 2003 shows that mean value of diffusivity in the open
ocean is 6.8Ã10-5 m2s-1, higher values are found in the area of the Deep Western
Boundary Current and over rough topography, where they exceed 10-3 m2s-1. |
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