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| Titel |
Modeling the Nd isotopic composition in the North Atlantic basin using an eddy-permitting model |
| VerfasserIn |
T. Arsouze, A. M. Treguier, S. Peronne, J.-C. Dutay, F. Lacan, C. Jeandel |
| 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 ; 6, no. 3 ; Nr. 6, no. 3 (2010-09-01), S.789-797 |
| Datensatznummer |
250003586
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| Publikation (Nr.) |
 copernicus.org/os-6-789-2010.pdf |
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| Zusammenfassung |
| Boundary Exchange (BE – exchange of elements between continental margins and
the open ocean) has been emphasized as a key process in the oceanic cycle of
neodymium (Nd) (Lacan and Jeandel, 2005a). Here, we use a regional
eddy-permitting resolution Ocean General Circulation Model (1/4°) of the
North Atlantic basin to simulate the distribution of the Nd isotopic
composition, considering BE as the only source. Results show good agreement
with the data, confirming previous results obtained using the same
parameterization of the source in a coarse resolution global model (Arsouze
et al., 2007), and therefore the major control played by the BE processes in
the Nd cycle on the regional scale. We quantified the exchange rate of the
BE, and found that the time needed for the continental margins to
significantly imprint the chemical composition of the surrounding seawater
(further referred as characteristic exchange time) is of the order of 0.2
years. However, the timescale of the BE may be subject to large variations
as a very short exchange time (a few days) is needed to reproduce the highly
negative values of surface waters in the Labrador Sea, whereas a longer one
(up to 0.5 years) is required to simulate the radiogenic influence of
basaltic margins and distinguish the negative isotopic signatures of North
Atlantic Deep Water from the more radiogenic southern origin water masses.
This likely represents geographical variations in erosion fluxes and the
subsequent particle load onto the continental margins. Although the
parameterization of the BE is the same in both configurations of the model,
the characteristic exchange time in the eddy-permitting configuration is
significantly lower than the previous evaluations using a low resolution
configuration (6 months to 10 years), but however in agreement with the
available seawater Nd isotope data. This results highlights the importance
of the model dynamics in simulating the BE process. |
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