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| Titel |
Understanding differences in East Antarctic ice cores during interglacials |
| VerfasserIn |
Louise Sime, Tom Bracegirdle, Eric Wolff, Valérie Masson-Delmotte, Kevin Oliver, Julia Tindall |
| 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 |
250053075
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| Zusammenfassung |
| Stable isotope ratios of oxygen and hydrogen in the Antarctic ice record provide invaluable
proxy temperature information. Conversions between of isotope observations in ice core and
past site temperatures have traditionally been based on geographical observations of the
spatial isotope-temperature relationship. The relationship is suggested to be uniform (±10%)
over the East Antarctic and constant with time (±20%), for climates cooler than present
day.
For warmer climates, an analyse of several long (340 kyr) ice core records from across
East Antarctica, alongside input from isotopic GCM modelling, indicated that for warmer
interglacial periods, conversions vary between different East Antarctic ice core sites (Sime et
al. 2009). Results indicate that the East Antarctic water isotopes tend to be less sensitive to
temperature changes during warmer climates. This indicates that previous temperature
estimates from interglacial climates are likely to be too low. The available evidence is
consistent with Antarctic interglacial temperatures that were significantly (more than 6oC)
higher than present day.
A fuller understanding of why variable ice core isotopic sensitivity occurs i.e. why some
East Antarctic ice core sites record larger isotopic fluctuations than others, will help in
constraining uncertainty on Antarctic interglacial climate reconstructions (Masson-Delmotte
et al., 2010). We present results from a new detailed multi-model analysis (Sime and
Bracegirdle, in prep). This analysis helps explain observed similarities, and differences,
between the East Antarctic Plateau ice core sites during interglacial climate changes (Sime et
al. 2009, Masson-Delmotte et al., 2010).
V. Masson-Delmotte et al. (2010) A comparison of the present and last interglacial
periods in six Antarctic ice cores Clim. Past Discuss., 6, 2267-2333
L. C. Sime, E. Wolff, K. Oliver, J.Tindall (2009) Evidence for warmer interglacials in
East Antarctic ice cores Nature, 462, 342-345
L. C. Sime and T. Bracegirdle Understanding differences in East Antarctic Plateau ice
cores during interglacials JGR - Atmos (in prep). |
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