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| Titel |
Ice thinning, upstream advection, and non-climatic biases for the upper 89% of the EDML ice core from a nested model of the Antarctic ice sheet |
| VerfasserIn |
P. Huybrechts, O. Rybak, F. Pattyn, U. Ruth, D. Steinhage |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 3, no. 4 ; Nr. 3, no. 4 (2007-10-02), S.577-589 |
| Datensatznummer |
250001174
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| Publikation (Nr.) |
 copernicus.org/cp-3-577-2007.pdf |
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| Zusammenfassung |
| A nested ice flow model was developed for eastern Dronning Maud Land to
assist with the dating and interpretation of the EDML deep ice core. The
model consists of a high-resolution higher-order ice dynamic flow model that
was nested into a comprehensive 3-D thermomechanical model of the whole
Antarctic ice sheet. As the drill site is on a flank position the
calculations specifically take into account the effects of horizontal
advection as deeper ice in the core originated from higher inland. First the
regional velocity field and ice sheet geometry is obtained from a forward
experiment over the last 8 glacial cycles. The result is subsequently
employed in a Lagrangian backtracing algorithm to provide particle paths
back to their time and place of deposition. The procedure directly yields
the depth-age distribution, surface conditions at particle origin, and a
suite of relevant parameters such as initial annual layer thickness. This
paper discusses the method and the main results of the experiment, including
the ice core chronology, the non-climatic corrections needed to extract the
climatic part of the signal, and the thinning function. The focus is on the
upper 89% of the ice core (appr. 170 kyears) as the dating below that is
increasingly less robust owing to the unknown value of the geothermal heat
flux. It is found that the temperature biases resulting from variations of
surface elevation are up to half of the magnitude of the climatic changes
themselves. |
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