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| Titel |
Climate variability of the mid- and high-latitudes of the Southern Hemisphere in ensemble simulations from 1500 to 2000 AD |
| VerfasserIn |
S. B. Wilmes, C. C. Raible, T. F. Stocker |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 8, no. 1 ; Nr. 8, no. 1 (2012-02-29), S.373-390 |
| Datensatznummer |
250005379
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| Publikation (Nr.) |
 copernicus.org/cp-8-373-2012.pdf |
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| Zusammenfassung |
| To increase the sparse knowledge of long-term Southern Hemisphere (SH)
climate variability, we assess an ensemble of 4 transient simulations over the
last 500 yr performed with a state-of-the-art atmosphere ocean general
circulation model. The model is forced with reconstructions of solar
irradiance, greenhouse gas (GHG) and volcanic aerosol concentrations. A 1990
control simulation shows that the model is able to represent the Southern
Annular Mode (SAM), and to some extent the South Pacific Dipole (SPD) and the
Zonal Wave 3 (ZW3). During the past 500 yr we find that SPD and ZW3
variability remain stable, whereas SAM shows a significant shift towards its
positive state during the 20th century. Regional temperatures over South
America are strongly influenced by changing both GHG concentrations and
volcanic eruptions, whereas precipitation shows no significant response to the
varying external forcing. For temperature this stands in contrast to proxy
records, suggesting that SH climate is dominated by internal variability
rather than external forcing. The underlying dynamics of the temperature
changes generally point to a combination of several modes, thus, hampering
the possibilities of regional reconstructing the modes from proxy records.
The linear imprint of the external forcing is as expected, i.e. a warming
for increase in the combined solar and GHG forcing and a cooling after
volcanic eruptions. Dynamically, only the increase in SAM with increased
combined forcing is simulated. |
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