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| Titel |
A model-data comparison of the Holocene global sea surface temperature evolution |
| VerfasserIn |
G. Lohmann, M. Pfeiffer, T. Laepple, G. Leduc, J.-H. Kim |
| 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 ; 9, no. 4 ; Nr. 9, no. 4 (2013-08-06), S.1807-1839 |
| Datensatznummer |
250085200
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| Publikation (Nr.) |
 copernicus.org/cp-9-1807-2013.pdf |
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| Zusammenfassung |
| We compare the ocean temperature evolution of the Holocene as simulated by
climate models and reconstructed from marine temperature proxies. We use
transient simulations from a coupled atmosphere–ocean general circulation
model, as well as an ensemble of time slice simulations from the
Paleoclimate Modelling Intercomparison Project. The general pattern of sea
surface temperature (SST) in the models shows a high-latitude cooling and a
low-latitude warming. The proxy dataset comprises a global compilation of
marine alkenone- and Mg/Ca-derived SST estimates. Independently of the
choice of the climate model, we observe significant mismatches between
modelled and estimated SST amplitudes in the trends for the last 6000 yr.
Alkenone-based SST records show a similar pattern as the simulated annual
mean SSTs, but the simulated SST trends underestimate the alkenone-based SST
trends by a factor of two to five. For Mg/Ca, no significant relationship
between model simulations and proxy reconstructions can be detected. We test
if such discrepancies can be caused by too simplistic interpretations of the
proxy data. We explore whether consideration of different growing seasons
and depth habitats of the planktonic organisms used for temperature
reconstruction could lead to a better agreement of model results with proxy
data on a regional scale. The extent to which temporal shifts in growing
season or vertical shifts in depth habitat can reduce model–data misfits is
determined. We find that invoking shifts in the living season and habitat
depth can remove some of the model–data discrepancies in SST trends.
Regardless whether such adjustments in the environmental parameters during
the Holocene are realistic, they indicate that when modelled temperature
trends are set up to allow drastic shifts in the ecological behaviour of
planktonic organisms, they do not capture the full range of reconstructed
SST trends. Results indicate that modelled and reconstructed temperature
trends are to a large degree only qualitatively comparable, thus providing a
challenge for the interpretation of proxy data as well as the model
sensitivity to orbital forcing. |
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