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| Titel |
Pre-LGM Northern Hemisphere ice sheet topography |
| VerfasserIn |
J. Kleman, J. Fastook, K. Ebert, J. Nilsson, R. Caballero |
| 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 ; 9, no. 5 ; Nr. 9, no. 5 (2013-10-22), S.2365-2378 |
| Datensatznummer |
250085235
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| Publikation (Nr.) |
 copernicus.org/cp-9-2365-2013.pdf |
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| Zusammenfassung |
| We here reconstruct the paleotopography of Northern Hemisphere ice sheets
during the glacial maxima of marine isotope stages (MIS) 5b and 4.We employ
a combined approach, blending geologically based reconstruction and
numerical modeling, to arrive at probable ice sheet extents and topographies
for each of these two time slices. For a physically based 3-D calculation
based on geologically derived 2-D constraints, we use the University of
Maine Ice Sheet Model (UMISM) to calculate ice sheet thickness and
topography. The approach and ice sheet modeling strategy is designed to
provide robust data sets of sufficient resolution for atmospheric
circulation experiments for these previously elusive time periods. Two
tunable parameters, a temperature scaling function applied to a spliced
Vostok–GRIP record, and spatial adjustment of the climatic pole position,
were employed iteratively to achieve a good fit to geological constraints
where such were available. The model credibly reproduces the first-order
pattern of size and location of geologically indicated ice sheets during
marine isotope stages (MIS) 5b (86.2 kyr model age) and 4 (64 kyr model
age). From the interglacial state of two north–south obstacles to
atmospheric circulation (Rocky Mountains and Greenland), by MIS 5b the
emergence of combined Quebec–central Arctic and Scandinavian–Barents-Kara
ice sheets had increased the number of such highland obstacles to four. The
number of major ice sheets remained constant through MIS 4, but the merging
of the Cordilleran and the proto-Laurentide Ice Sheet produced a single
continent-wide North American ice sheet at the LGM. |
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