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| Titel |
Influence of freshwater input on the skill of decadal forecast of sea ice in the Southern Ocean |
| VerfasserIn |
V. Zunz, H. Goosse |
| 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 ; 9, no. 2 ; Nr. 9, no. 2 (2015-03-17), S.541-556 |
| Datensatznummer |
250116768
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| Publikation (Nr.) |
 copernicus.org/tc-9-541-2015.pdf |
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| Zusammenfassung |
| Recent studies have investigated the potential link between the
freshwater input derived from the melting of the Antarctic ice sheet
and the observed recent increase in sea ice extent in the Southern
Ocean. In this study, we assess the impact of an additional
freshwater flux on the trend in sea ice extent and concentration in
simulations with data assimilation, spanning the period 1850–2009,
as well as in retrospective forecasts (hindcasts) initialised in
1980. In the simulations with data assimilation,
the inclusion of an additional freshwater flux that follows an autoregressive process
improves the reconstruction of the trend in ice extent and
concentration between 1980 and 2009. This is linked
to a better efficiency of the data assimilation
procedure but can also be due to a better
representation of the freshwater cycle in the Southern Ocean.
The results of the hindcast simulations
show that an adequate initial state, reconstructed
thanks to the data assimilation procedure including an additional
freshwater flux, can lead to an increase
in the sea ice extent spanning several decades
that is in agreement with satellite observations. In our hindcast
simulations, an increase in sea ice extent is obtained even in the
absence of any major change in the freshwater input over the last decades. Therefore, while the
additional freshwater flux appears to play a key role in the reconstruction of
the evolution of the sea ice in the simulation with data assimilation,
it does not seem to be required in the hindcast simulations.
The present work thus provides encouraging results for sea ice predictions in the
Southern Ocean, as in our simulation the positive trend in ice extent
over the last 30 years is largely determined by the state of
the system in the late 1970s. |
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