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| Titel |
Greenland ice sheet model parameters constrained using simulations of the Eemian Interglacial |
| VerfasserIn |
A. Robinson, R. Calov, A. Ganopolski |
| 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 ; 7, no. 2 ; Nr. 7, no. 2 (2011-04-26), S.381-396 |
| Datensatznummer |
250004506
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| Publikation (Nr.) |
 copernicus.org/cp-7-381-2011.pdf |
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| Zusammenfassung |
| Using a new approach to force an ice sheet model, we performed an ensemble of
simulations of the Greenland Ice Sheet evolution during the last two glacial
cycles, with emphasis on the Eemian Interglacial. This ensemble was generated
by perturbing four key parameters in the coupled regional climate-ice sheet
model and by introducing additional uncertainty in the prescribed
"background" climate change. The sensitivity of the surface melt model to
climate change was determined to be the dominant driver of ice sheet
instability, as reflected by simulated ice sheet loss during the Eemian
Interglacial period. To eliminate unrealistic parameter combinations,
constraints from present-day and paleo information were applied. The
constraints include (i) the diagnosed present-day surface mass balance
partition between surface melting and ice discharge at the margin, (ii) the
modeled present-day elevation at GRIP; and (iii) the modeled elevation
reduction at GRIP during the Eemian. Using these three constraints, a total
of 360 simulations with 90 different model realizations were filtered down to
46 simulations and 20 model realizations considered valid. The paleo
constraint eliminated more sensitive melt parameter values, in agreement with
the surface mass balance partition assumption. The constrained simulations
resulted in a range of Eemian ice loss of 0.4–4.4 m sea level
equivalent, with a more likely range of about 3.7–4.4 m sea level if the GRIP
δ18O isotope record can be considered an accurate proxy for the
precipitation-weighted annual mean temperatures. |
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