 |
| Titel |
Temporal and spatial 17O-excess variations reflect changes in the hydrological cycle except in remote central east Antarctica |
| VerfasserIn |
Renato Winkler, Amaëlle Landais, Frédéric Prié, Barbara Stenni, Andrew Moy, Tas van Ommen, Elise Fourré, Philippe Jean-baptiste, Jean-Jacques Beley, Jean Jouzel |
| Konferenz |
EGU General Assembly 2011
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250054226
|
|
|
|
|
|
| Zusammenfassung |
| For many decades stable water isotopes (δD and δ18O) have been used as tracers of the
earth’s hydrological cycle in order to get information about climatic parameters. In the low
latitudes, water isotopes trace precipitation rate (amount effect), history of air masses,
regional convection or water vapor transport. In higher latitudes, δD and δ18O are directly
linked to condensation temperature at first order while the combination of both in
d-excess
[= δD – 8 δ18O] gives indication on source climatic conditions. The recent development
of 17O-excess [= ln(δ17O + 1) – 0.528ln(δ18O + 1)], resulting from the combination of δ17O
and δ18O, now provides an additional isotopic tracer which has been shown to be primary
influenced by relative humidity at evaporation. Here, we show new results of 17O-excess in
precipitation from tropical to polar regions which better characterize the link between
hydrological cycle and climate at the different locations based on the 17O-excess
signature.
First, we present a compilation of 17O-excess on natural water sources in France,
Turkey, Mexico and Argentina from precipitation and groundwater and show that the
17O-excess signature helps to decipher the different sources of water. Then, we compare
the 17O-excess variations over the deglaciation in Antarctica from 4 different ice
cores (2 coastal ones: TALDICE and LAW DOME – DSS; 2 central ones: EPICA
DOME C and Vostok) which show different behaviours. While the 17O-excess
record from the coastal ice cores seems to faithfully record the variations of relative
humidity at the source regions providing moisture to Antarctica, the 17O-excess record
in central East Antarctica seems to be affected more by local effects. In order to
further constrain the local variations of 17O-excess in remote central east Antarctica,
we explore the interannual 17O-excess variations from a snow pit at the Vostok
station.
These new 17O-excess results of the European and South American continents,
together with the data from Antarctica, span a wide range of very different climatic
conditions and therefore allow us to test our current understanding of 17O-excess. |
|
|
|
|
|
|