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| Titel |
Modelling large-scale ice-sheet–climate interactions following glacial inception |
| VerfasserIn |
J. M. Gregory, O. J. H. Browne, A. J. Payne, J. K. Ridley, I. C. Rutt |
| 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 ; 8, no. 5 ; Nr. 8, no. 5 (2012-10-11), S.1565-1580 |
| Datensatznummer |
250005843
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| Publikation (Nr.) |
 copernicus.org/cp-8-1565-2012.pdf |
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| Zusammenfassung |
| We have coupled the FAMOUS global AOGCM (atmosphere-ocean general
circulation model) to the Glimmer thermomechanical ice-sheet model in
order to study the development of ice-sheets in north-east America
(Laurentia) and north-west Europe (Fennoscandia) following glacial
inception.
This first use of a coupled AOGCM–ice-sheet model for a study of change
on long palæoclimate timescales is made possible by the low
computational cost of FAMOUS, despite its inclusion of physical
parameterisations similar in complexity to higher-resolution
AOGCMs.
With the orbital forcing of 115 ka BP, FAMOUS–Glimmer produces
ice caps on the Canadian Arctic islands, on the north-west coast of
Hudson Bay and in southern Scandinavia, which grow to
occupy the Keewatin region of the Canadian mainland and all of
Fennoscandia over 50 ka.
Their growth is eventually halted by increasing coastal ice discharge.
The expansion of the ice-sheets influences the regional climate, which
becomes cooler, reducing the ablation, and ice accumulates in places
that initially do not have positive surface mass balance.
The results suggest the possibility that the glaciation of north-east
America could have begun on the Canadian Arctic islands, producing a
regional climate change that caused or enhanced the growth of ice on the
mainland.
The increase in albedo (due to snow and ice cover) is the dominant
feedback on the area of the ice-sheets and acts rapidly, whereas the
feedback of topography on SMB does not become significant for several
centuries, but eventually has a large effect on the thickening of the
ice-sheets.
These two positive feedbacks are mutually reinforcing.
In addition, the change in topography perturbs the tropospheric
circulation, producing some reduction of cloud, and mitigating the local
cooling along the margin of the Laurentide ice-sheet.
Our experiments demonstrate the importance and complexity of the
interactions between ice-sheets and local climate. |
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