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| Titel |
Spatial variation of diapycnal mixing from hydrographic surveys in the subpolar North Atlantic |
| VerfasserIn |
M. Li, C. Mertens, M. Walter, M. Rhein |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250066952
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| Zusammenfassung |
| Mixing induced transformation of water masses maintains the ocean stratification and
supports the Meridiornal Overturning Circulation. During the year 2003-2010, eight
large-scale hydrographic survey cruises were carried out with combined CTD/LADCP
measurements in the subpolar North Atlantic. Observational data are analyzed to get an
overview of the extent of diapycnal mixing in this area.
It is found the magnitude of diffusivity KÏ in mid-depth ocean is O(10-4m2s-1), but
mixing is obviously intensified over rough topography (Mid Atlantic Ridge), in the region of
Western Boundary Current (WBC), and to the north of Greenland. In some regions, KÏ can
exceed O(10-3m2s-1). Diapycnal diffusivity is significantly dependent on the bottom
roughness and bathymetry. A linear fit is made between logarithms of bottom diffusivity and
variance of topography. In general, the diapycnal diffusivity and the shear/strain variance
ratio both increase with depth. The mean value of shear/strain variance ratio in this area is
5.3, indicating that internal wave field may not have so much energy as expected by Kunze et
al. (2006). |
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