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| Titel |
Investigating Late Cretaceous Ice sheets |
| VerfasserIn |
S. J. Hunter, J. E. Francis, A. M. Haywood, R. C. A. Hindmarsh, P. J. Valdes |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250030350
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| Zusammenfassung |
| The Cretaceous period has traditionally been reconstructed as being warm and ice-free, yet
recent investigation of sea-level change that occurred during this period suggests a possible
glacial origin. The most plausible cause being the growth and decay of moderate sized
ice-sheets. This project aims to investigate this hypothesis, by exploring the form of
possible Antarctic ice-sheets during the Maastrichtian. We use a palaeoclimatic
proxy database to provide both boundary conditions and evaluation data for a suite
of HadCM3l GCM predicted climates. These climates are then used to drive an
ice-sheet model. Offline coupling of the ice sheet and climate models is used to
incorporate additional feedbacks and to explore the compatibility between ice sheet and
climate.
Here results are presented from the terrestrial and surface ocean data/model
comparison and the subsequent ice-sheet model sensitivity experiments. Whilst at times
demonstrating a good agreement between proxy and the predicted climate envelope, well
known model-data discrepancies particularly in the high latitudes are observed.
The magnitudes of derived ice-sheet envelopes are significantly less than those
predicted from sea-level reconstructions, for example, 2Ã pre-industrial CO2 levels
with a favourable orbit lead to an upper limit of between 3-4 Ã 106 km3 of ice. We
conclude by discussing the implications of the limitations and findings of this study. |
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