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| Titel |
Weak temperature control of Greenland δ¹⁸O during the previous interglacial |
| VerfasserIn |
Jesper Sjolte, Georg Hoffmann |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048308
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| Zusammenfassung |
| We present a model study of the isotopic composition of Greenland precipitation during the
previous interglacial, the Eemian. A global climate model with isotopic tracers is run in three
time slice experiments (115 kyr, 122 kyr, 126 kyr) during the Eemian. Sea surface
temperatures and the orbital parameters are adjusted to Eemian values, while all
other boundary conditions are kept at preindustrial values. The modeled summer
temperature anomalies during the Eemian climatic optimum, considered here to be 126
kyr, matches well with proxy data in magnitude and spatial distribution for the
Northern Hemisphere. The modeled maximum summer anomaly for Greenland is
+6oC. For annual mean δ18O the model results show an anomaly of +0.28 permil
compared to the anomaly of +3 permil found in ice cores. The limited response of the
modeled δ18O is attributed to a southward shift in the moisture source region and
the use of the present day ice sheet configuration. The shift in moisture source
is recognized as a change in evaporation patterns and moisture advection. This
degrades the coherency between temperature and δ18O for the warmest part of the
Eemian. On the grounds of Eemian anomalies in modeled δ18O and ice core δ18O the
decrease in elevation of the Greenland ice sheet is estimated for a number of ice
core sites ranging from 900 m lower (Dye-3) to 400 m lower (GISP2) compared to
present. |
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