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Titel |
Projections of ice shelf basal melting in a global finite element sea ice - ice shelf - ocean model |
VerfasserIn |
R. Timmermann, H. H. Hellmer |
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 |
250068657
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Zusammenfassung |
In the framework of the EU project Ice2sea we utilize a global finite element sea ice - ice
shelf - ocean model (FESOM), focused on the Antarctic marginal seas, to quantify heat and
freshwater fluxes in the Antarctic ice shelf cavities and to assess ice shelf basal melting in a
warmer climate. Ice shelf - ocean interaction is described using a three-equation system with
a diagnostic computation of temperature and salinity at the ice-ocean interface. A tetrahedral
mesh with a minimum horizontal resolution of 4 minutes and hybrid vertical coordinates is
used. Ice shelf draft, cavity geometry, and global ocean bathymetry have been derived from
the RTopo-1 data set. Additional simulations were carried out with the circumpolar
coarse-scale finite-difference model developed as part of the Bremerhaven Regional Ice
Ocean Simulations (BRIOS).
Simulations for present-day climate were forced with the NCEP reanalysis product and
the atmospheric output from 20th century simulations of the Hadley Centre Climate Model
(HadCM3). The projections for the period 2000-2199 use the output of HadCM3 simulations
for the IPCC scenarios A1B and E1. Results from both models indicate a strong
sensitivity of basal melting to increased ocean temperatures for the ice shelves in
Amundsen Sea. An even stronger impact is found for warm water starting to pulse
onto the southern Weddell Sea continental shelf in the middle of the 21st century,
originating from a redirected coastal current. As these pulses propagate far into the
Filchner-Ronne Ice Shelf (FRIS) cavity, basal melting increases significantly compared
to the present value of about 100 Gt/yr. At the end of the 21st / beginning of the
22nd century both models suggest a stabilization of FRIS basal mass loss on a high
level. |
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