 |
| Titel |
Perspectives of transient tracer applications and limiting cases |
| VerfasserIn |
T. Stöven, T. Tanhua, M. Hoppema, J. L. Bullister |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1812-0784
|
| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 11, no. 5 ; Nr. 11, no. 5 (2015-09-18), S.699-718 |
| Datensatznummer |
250117289
|
| Publikation (Nr.) |
 copernicus.org/os-11-699-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
Currently available transient tracers have different application ranges that
are defined by their temporal input (chronological transient tracers) or
their decay rate (radioactive transient tracers). Transient tracers range
from tracers for highly ventilated water masses such as sulfur hexafluoride
(SF6) through tritium (3H) and chlorofluorocarbons (CFCs) up to
tracers for less ventilated deep ocean basins such as argon-39 (39Ar)
and radiocarbon (14C). In this context, highly ventilated water masses
are defined as water masses that have been in contact with the atmosphere
during the last decade. Transient tracers can be used to empirically
constrain the transit time distribution (TTD), which can often be
approximated with an inverse Gaussian (IG) distribution. The IG-TTD provides
information about ventilation and the advective/diffusive characteristics of
a water parcel.
Here we provide an overview of commonly used transient tracer couples and the
corresponding application range of the IG-TTD by using the new concept of
validity areas. CFC-12, CFC-11 and SF6 data from three different cruises
in the South Atlantic Ocean and Southern Ocean as well as 39Ar data from
the 1980s and early 1990s in the eastern Atlantic Ocean and the Weddell Sea
are used to demonstrate this method. We found that the IG-TTD can be
constrained along the Greenwich Meridian south to 46° S, which
corresponds to the Subantarctic Front (SAF) denoting the application limit.
The Antarctic Intermediate Water (AAIW) describes the limiting water layer in
the vertical. Conspicuous high or lower ratios between the advective and
diffusive components describe the transition between the validity area and
the application limit of the IG-TTD model rather than describing the physical
properties of the water parcel. The combination of 39Ar and CFC data
places constraints on the IG-TTD in the deep water north of the SAF, but not
beyond this limit. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|