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| Titel |
Estimating 750 years of temperature variations and uncertainties in the Pyrenees by tree-ring reconstructions and climate simulations |
| VerfasserIn |
I. Dorado Liñán, U. Büntgen, F. González-Rouco, E. Zorita, J. P. Montávez, J. J. Gómez-Navarro, M. Brunet, I. Heinrich, G. Helle, E. Gutiérrez |
| 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. 3 ; Nr. 8, no. 3 (2012-05-24), S.919-933 |
| Datensatznummer |
250005585
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| Publikation (Nr.) |
 copernicus.org/cp-8-919-2012.pdf |
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| Zusammenfassung |
Past temperature variations are usually inferred from proxy data or
estimated using general circulation models. Comparisons between climate
estimations derived from proxy records and from model simulations help to
better understand mechanisms driving climate variations, and also offer the
possibility to identify deficiencies in both approaches.
This paper presents regional temperature reconstructions based on tree-ring
maximum density series in the Pyrenees, and compares them with the output of
global simulations for this region and with regional climate model
simulations conducted for the target region. An ensemble of 24 reconstructions
of May-to-September regional mean temperature was derived
from 22 maximum density tree-ring site chronologies distributed over the
larger Pyrenees area. Four different tree-ring series standardization
procedures were applied, combining two detrending methods: 300-yr spline
and the regional curve standardization (RCS). Additionally, different
methodological variants for the regional chronology were generated by using
three different aggregation methods. Calibration verification trials were
performed in split periods and using two methods: regression and a simple
variance matching. The resulting set of temperature reconstructions was
compared with climate simulations performed with global (ECHO-G) and
regional (MM5) climate models.
The 24 variants of May-to-September temperature reconstructions reveal a
generally coherent pattern of inter-annual to multi-centennial temperature
variations in the Pyrenees region for the last 750 yr. However, some
reconstructions display a marked positive trend for the entire length of the
reconstruction, pointing out that the application of the RCS method to a
suboptimal set of samples may lead to unreliable results.
Climate model simulations agree with the tree-ring based reconstructions at
multi-decadal time scales, suggesting solar variability and volcanism as the
main factors controlling preindustrial mean temperature variations in the
Pyrenees. Nevertheless, the comparison also highlights differences with the
reconstructions, mainly in the amplitude of past temperature variations and
in the 20th century trends. Neither proxy-based reconstructions nor
model simulations are able to perfectly track the temperature variations of
the instrumental record, suggesting that both approximations still need
further improvements. |
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