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Titel |
Estimating the Greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR |
VerfasserIn |
X. Fettweis, B. Franco, M. Tedesco, J. H. Angelen, J. T. M. Lenaerts, M. R. Broeke, H. Gallée |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1994-0416
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Digitales Dokument |
URL |
Erschienen |
In: The Cryosphere ; 7, no. 2 ; Nr. 7, no. 2 (2013-03-14), S.469-489 |
Datensatznummer |
250017944
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Publikation (Nr.) |
copernicus.org/tc-7-469-2013.pdf |
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Zusammenfassung |
To estimate the sea level rise (SLR) originating from changes in surface mass
balance (SMB) of the Greenland ice sheet (GrIS), we present 21st century
climate projections obtained with the regional climate model MAR (Modèle Atmosphérique Régional), forced by
output of three CMIP5 (Coupled Model Intercomparison Project Phase 5) general circulation models (GCMs). Our results indicate
that in a warmer climate, mass gain from increased winter snowfall over the
GrIS does not compensate mass loss through increased meltwater run-off in
summer. Despite the large spread in the projected near-surface warming, all
the MAR projections show similar non-linear increase of GrIS surface melt
volume because no change is projected in the general atmospheric circulation
over Greenland. By coarsely estimating the GrIS SMB changes from GCM output,
we show that the uncertainty from the GCM-based forcing represents about half
of the projected SMB changes. In 2100, the CMIP5 ensemble mean projects a
GrIS SMB decrease equivalent to a mean SLR of +4 ± 2 cm and +9 ± 4 cm
for the RCP (Representative Concentration Pathways) 4.5 and RCP 8.5 scenarios respectively. These estimates do not
consider the positive melt–elevation feedback, although sensitivity
experiments using perturbed ice sheet topographies consistent with the
projected SMB changes demonstrate that this is a significant feedback, and
highlight the importance of coupling regional climate models to an ice sheet
model. Such a coupling will allow the assessment of future response of both
surface processes and ice-dynamic changes to rising temperatures, as well as
their mutual feedbacks. |
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