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| Titel |
Combining water and gas isotopes measurements from the NEEM ice core to reconstruct abrupt temperature changes and reorganization of the hydrological cycle over a series of Dansgaard-Oeschger events |
| VerfasserIn |
M. Guillevic, L. Bazin, C. Stowasser, A. Landais, V. Masson-Delmotte, B. Minster, F. Prié, T. Blunier, S. L. Buchardt, B. M. Vinther, M. Leuenberger |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250062682
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| Zusammenfassung |
| Ice cores from Greenland have revealed the occurrence of 25 rapid climatic events
(Dansgaard-Oeschger events, hereafter DO events) during the last glacial period. These DO
events have a very strong temperature signal in Greenland (more than 15-ă temperature
increase in less than a century) with an imprint of almost global extent. Open questions exist
on the regional fingerprints of DO events in Greenland. The exact reorganization of the
northern hemisphere water cycle and the sequence of events between low and high latitudes
remain uncertain. In this study, we combine new measurements of water stable isotopes (δD,
δ18O, δ17O) and air isotopes (δ15N of N2, δ40Ar of Ar) every 50 years on a sequence of three
DO events (8-10) on the NEEM ice core (North Greenland Eemian Ice Drilling, North
West Greenland). The isotopic composition of water, through the second order
parameters deuterium excess and 17O-excess, allow to document changes in sea
surface temperature and humidity at the evaporative regions at low latitudes. The
comparison of δ18O with d-excess and 17O-excess therefore allows to quantify the
time lags between changes in Greenland temperature and changes in low latitudes
evaporative conditions. The magnitude of temperature changes is quantified based on gas
isotopes. The isotope and temperature patterns observed during DO 8-10 at NEEM
are compared with results obtained from GRIP, GISP2 and NorthGRIP ice cores
to discuss the regional signature of DO events in Greenland. Finally, the gas and
water isotope signals are compared with the methane records to characterize the
sequence of events between low latitude methane production and polar climate. |
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