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| Titel |
A fully coupled 3-D ice-sheet - sea-level model: algorithm and applications |
| VerfasserIn |
Bas De Boer, Paolo Stocchi, Roderik van de Wal |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250093484
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| Publikation (Nr.) |
 EGU/EGU2014-8252.pdf |
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| Zusammenfassung |
| Relative sea-level (RSL) variations during the late Pleistocene cannot be reconstructed
regardless of the estimates of ice-volume fluctuations. For the latter, however, the knowledge
of regional and global relative sea-level variations is necessary. Overcoming this problem of
circularity demands a fully coupled system where ice sheets and sea level vary consistently in
space and time and dynamically affect each other. Here we present results for the past
410,000 years from the coupling of a set of 3-D ice-sheet-shelf models to a global sea-level
model based on the solution of gravitationally self-consistent sea-level equation. The
sea-level model incorporates all the Glacial Isostatic Adjustment feedbacks for a Maxwell
viscoelastic and rotating Earth model with variable coastlines. Ice volume is computed
with four 3-D ice-sheet-shelf models for North America, Eurasia, Greenland and
Antarctica. With an inverse approach, ice volume and temperature are derived from a
benthic δ18O stacked record. We show the dynamical response of the ice sheets to
changes in RSL, the latter including both the deformation of the bedrock to ice
and water loading and the geoidal deformations. Due to the self-gravitational pull
of the ice sheet, RSL close to the ice sheets is higher than the eustatic sea level,
and thus acts to stabilise ice sheets. Especially for the West Antarctic ice sheet,
ice volume is lower during glacial periods relative to the uncoupled simulation.
When using the Maxwell viscoelastic Earth model, the bedrock deformation due
to ice loading is lower compared to the simple flexural Earth model used in the
uncoupled experiments. Altogether, the coupled model results in lower ice volume
during glacial periods relative to an uncoupled simulation that uses eustatic sea level
derived from ice-volume changes only. The time dependent ocean function, however,
accounts for the changes in the coastlines over the globe. This leads to a significant
reduction of the ocean area during glacial maxima in the coupled simulation. Hence,
eustatic sea level change for the coupled simulation is largely similar to the uncoupled
simulation. Our simulated RSL changes are generally in good agreement with the
RSL reconstructions derived from geological and archaeological paleo sea-level
indicators from sites in Scandinavia, North America, the Caribbean and Antarctica. |
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