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| Titel |
Modeling of the anthropogenic tritium transient, and its decay product Helium-3, in the Mediterranean Sea, using a high-resolution regional model. |
| VerfasserIn |
Mohamed Ayache, Jean-Claude Dutay, Philippe Jean-baptiste, Karine Béranger, Thomas Arsouze, Jonathan Beuvier, Julien Palmiéri, Briac Le-Vu, Wolfgang Roether |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250091878
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| Publikation (Nr.) |
 EGU/EGU2014-6193.pdf |
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| Zusammenfassung |
| This numerical study provides, for the first time in the Mediterranean Sea, a simulation of the
anthropogenic tritium invasion and its decay product helium-3. The simulation is starting in
1950 and go up to 2011. It thus covers a 60-year period spanning the entire tritium transient
generated by the atmospheric nuclear-weapon tests performed in the 1950s and early 1960s.
The tritium is known as a passive tracer, which allows a good representation/signature of the
upper water stratification, as well as, the high mixing in convection areas and the spreading at
intermediate/deep levels. The tracer simulation is done using a high resolution regional model
NEMO-MED12 (Beuvier et al., JGR, 2012) with at surface prescribed tritium concentration
according to the temporal evolution derived from observations (see Roether et al., OS,
2013).
Several measurement of tritium and helium-3 performed along large scale transects in the
Mediterranean Sea during the last decades allow a comparison of the simulated results with
numerous in situ sections from cruises of Meteor M5/6, M31/1, M44/4, M51/2, M84/3, and
Poseidon 234. The results show that the parameterization used for the tritium boundary
conditions generates realistic results. Besides we calculate the tracer-age distributions
according to the relationship between tritium and its radioactive decay product helium-3. In
the eastern basin, the tracer simulation results highlight the weak formation of Adriatic Deep
Water (ADW) in the Adriatic Sea followed by a week contribution to the Eastern
Mediterranean Deep Water (EMDW) in the Ionian sub-basin while it shows a good
representation of the Eastern Mediterranean Transient (EMT) signal from the Aegean Sea
followed by a great contribution to the EMDW. In the western basin, the particularly
intense deep convection event of winter 2005 in the Gulf of Lions during the Western
Mediterranean Transition (WMT) is well simulated. However the spreading of the
recently ventilated deep water to the south is too weak as mentioned in Beuvier et al.
(2012). Finally, at intermediate levels, the spreading of the Levantine Intermediate
Water (LIW) from the eastern basin towards the western basin is relatively well
simulated when the simulated tracer-age distribution is compared to observation-based
estimates.
Keywords: Mediterranean Sea; Tritium; Helium-3; Tritium-helium ages; Regional Ocean
Modeling. |
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