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| Titel |
Anthropogenic climate change and the Greenland ice sheet |
| VerfasserIn |
U. Mikolajewicz, M. Vizcaíno, C. Rodehacke, F. Ziemen |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250064809
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| Zusammenfassung |
| In the standard CMIP5 simulations the ice sheets are kept fixed. Only few groups
have been able to perform CMIP5 simulations with interactively coupled ice sheet
models. Beside its importance for the future evolution of global mean sea level, the
Greenland ice sheet also has the potential to strongly affect deep water formation,
especially in the Labrador Sea, but also in the Nordic Seas. Here we present a set
of simulations with two interactively coupled ice sheet models, which allows to
assess the uncertainty arising from both the ice sheet model as well as the coupling
technique.
The climate model ECHAM5/MPIOM is coupled interactively to two different ice sheet
models using two different coupling strategies. The ice sheet models are a Greenland set-up
of SICOPOLIS with 10 km horizontal resolution and a northern hemisphere set-up of PISM
with a horizontal resolution of 20 km. The coupling is done either with a simple positive
degree days approach or a mass-balance scheme calculating the surface melting with an
energy-balance scheme. The atmospheric forcing is applied directly to the ice sheet model
without flux correction or anomaly coupling, which avoids inconsistencies between the
models.
The resulting net mass loss rates for the Greenland ice sheet in a 1-percent-scenario
capped at 4x preindustrial atmospheric CO2 concentrations show a considerable dependence
on both ice sheet model and coupling technique. The resulting differences in atmospheric
climate, however, are small within the first centuries and restricted to the immediate vicinity
of Greenland.
The feedbacks between atmosphere, ocean and the Greenland ice sheet are studied in a
series of sensitivity experiments, where individual feedbacks were suppressed. It turns out
that the future development of the Atlantic overturning and its associated heat transport are
quite important for the future evolution of the Greenland ice sheet: The stronger
the Atlantic overturning remains, the stronger the mass loss of the Greenland ice
sheet.
Results from the simulations using the actual scenarios applied for the CMIP5
simulations are presented as well. |
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