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| Titel |
Investigating the consistency between proxy-based reconstructions and climate models using data assimilation: a mid-Holocene case study |
| VerfasserIn |
A. Mairesse, H. Goosse, P. Mathiot, H. Wanner, S. Dubinkina |
| 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. 6 ; Nr. 9, no. 6 (2013-12-06), S.2741-2757 |
| Datensatznummer |
250085272
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| Publikation (Nr.) |
 copernicus.org/cp-9-2741-2013.pdf |
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| Zusammenfassung |
| The mid-Holocene (6 kyr BP; thousand years before present) is a key period
to study the consistency between model results and proxy-based
reconstruction data as it corresponds to a standard test for models and a reasonable number of
proxy-based records is available. Taking advantage of this relatively
large amount of information, we have compared a compilation of
50 air and sea surface temperature reconstructions with the results
of three simulations performed with general circulation models and
one carried out with LOVECLIM, a model of intermediate
complexity. The conclusions derived from this analysis confirm that
models and data agree on the large-scale spatial pattern but
the models underestimate the magnitude of some observed changes and that large
discrepancies are observed at the local scale. To further
investigate the origin of those inconsistencies, we have constrained
LOVECLIM to follow the signal recorded by the proxies selected in
the compilation using a data-assimilation method based on a particle
filter. In one simulation, all the 50 proxy-based records are used while in the
other two only the continental or oceanic proxy-based records constrain the
model results.
As expected, data assimilation leads to improving the consistency between
model results and the reconstructions. In particular, this is
achieved in a robust way in all the experiments through
a strengthening of the westerlies at midlatitude that warms up
northern Europe. Furthermore, the comparison of the LOVECLIM
simulations with and without data assimilation has also objectively
identified 16 proxy-based paleoclimate records whose reconstructed signal is either
incompatible with the signal recorded by some other proxy-based records or with
model physics. |
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