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| Titel |
Meridional transport of salt in the global ocean from an eddy-resolving model |
| VerfasserIn |
A. M. Treguier, J. Deshayes, J. Le Sommer, C. Lique, G. Madec, T. Penduff, J.-M. Molines, B. Barnier, R. Bourdallé-Badie, C. Talandier |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1812-0784
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| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 10, no. 2 ; Nr. 10, no. 2 (2014-04-17), S.243-255 |
| Datensatznummer |
250116968
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| Publikation (Nr.) |
 copernicus.org/os-10-243-2014.pdf |
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| Zusammenfassung |
| The meridional transport of
salt is computed in a global eddy-resolving numerical model (1/12°
resolution) in order to improve our understanding of the ocean salinity
budget. A methodology is proposed that allows a global analysis of the
salinity balance in relation to surface water fluxes, without defining a
"freshwater anomaly" based on an arbitrary reference salinity. The method
consists of a decomposition of the meridional transport into (i) the
transport by the time–longitude–depth mean velocity, (ii) time–mean
velocity recirculations and (iii) transient eddy perturbations. Water is
added (rainfall and rivers) or removed (evaporation) at the ocean surface at
different latitudes, which creates convergences and divergences of mass
transport with maximum and minimum values close to ±1 Sv. The resulting
meridional velocity effects a net transport of salt at each latitude
(±30 Sv PSU), which is balanced by the time–mean recirculations and by
the net effect of eddy salinity–velocity correlations. This balance ensures
that the total meridional transport of salt is close to zero, a necessary
condition for maintaining a quasi-stationary salinity distribution. Our model
confirms that the eddy salt transport cannot be neglected: it is comparable
to the transport by the time–mean recirculation (up to 15 Sv PSU) at the
poleward and equatorial boundaries of the subtropical gyres. Two different
mechanisms are found: eddy contributions are localized in intense currents
such as the Kuroshio at the poleward boundary of the subtropical gyres, while
they are distributed across the basins at the equatorward boundaries.
Closer to the Equator, salinity–velocity correlations are mainly due to the
seasonal cycle and large-scale perturbations such as tropical instability
waves. |
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