 |
| Titel |
Simulation of the mantle and crustal helium isotope signature in the Mediterranean Sea using a high-resolution regional circulation model |
| VerfasserIn |
M. Ayache, J.-C. Dutay, P. Jean-Baptiste, E. Fourré |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1812-0784
|
| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 11, no. 6 ; Nr. 11, no. 6 (2015-12-21), S.965-978 |
| Datensatznummer |
250117333
|
| Publikation (Nr.) |
 copernicus.org/os-11-965-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
Helium isotopes (3He, 4He) are useful tracers for
investigating the deep ocean circulation and for evaluating ocean general
circulation models, because helium is a stable and conservative nuclide that
does not take part in any chemical or biological process. Helium in the ocean
originates from three different sources, namely, (i) gas dissolution in
equilibrium with atmospheric helium, (ii) helium-3 addition by radioactive
decay of tritium (called tritiugenic helium), and (iii) injection of
terrigenic helium-3 and helium-4 by the submarine volcanic activity which
occurs mainly at plate boundaries, and also addition of (mainly) helium-4
from the crust and sedimentary cover by α-decay of uranium and thorium
contained in various minerals.
We present the first simulation of the terrigenic helium isotope distribution
in the whole Mediterranean Sea using a high-resolution model (NEMO-MED12).
For this simulation we build a simple source function for terrigenic helium
isotopes based on published estimates of terrestrial helium fluxes. We
estimate a hydrothermal flux of 3.5 mol3 He yr−1 and a lower
limit for the crustal flux at 1.6 × 10−7
4He mol m−2 yr−1.
In addition to providing constraints on helium isotope degassing fluxes in
the Mediterranean, our simulations provide information on the ventilation of
the deep Mediterranean waters which is useful for assessing NEMO-MED12
performance. This study is part of the work carried out to assess the
robustness of the NEMO-MED12 model, which will be used to study the evolution
of the climate and its effect on the biogeochemical cycles in the
Mediterranean Sea, and to improve our ability to predict the future evolution
of the Mediterranean Sea under the increasing anthropogenic pressure. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|