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| Titel |
How does internal variability influence the ability of CMIP5 models to reproduce the recent trend in Southern Ocean sea ice extent? |
| VerfasserIn |
V. Zunz, H. Goosse, F. Massonnet |
| 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 (2013-03-12), S.451-468 |
| Datensatznummer |
250017943
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| Publikation (Nr.) |
 copernicus.org/tc-7-451-2013.pdf |
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| Zusammenfassung |
| Observations over the last 30 yr have shown that the sea ice extent
in the Southern Ocean has slightly increased since 1979. Mechanisms
responsible for this positive trend have not been well established
yet. In this study we tackle two related issues:
is the observed positive trend compatible with the internal variability
of the system, and do the models agree with what we know about
the observed internal variability? For that
purpose, we analyse the evolution of sea ice around the Antarctic
simulated by 24 different general circulation models involved in the
5th Coupled Model Intercomparison Project (CMIP5),
using both historical and hindcast experiments.
Our analyses show that CMIP5 models respond to the
forcing, including the one induced by stratospheric ozone depletion,
by reducing the sea ice cover in the Southern Ocean. Some
simulations display an increase in sea ice extent similar to the observed
one. According to models, the observed positive trend is compatible
with internal variability. However, models
strongly overestimate the variance of sea ice extent and the
initialization methods currently used in models do not improve
systematically the simulated trends in sea ice extent. On the basis
of those results, a critical role of the internal variability in the
observed increase of sea ice extent in the Southern Ocean could
not be ruled out, but current models results appear inadequate to
test more precisely this hypothesis. |
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