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| Titel |
Reconciling reconstructed and simulated features of the winter Pacific/North American pattern in the early 19th century |
| VerfasserIn |
D. Zanchettin, O. Bothe, F. Lehner, P. Ortega, C. C. Raible, D. Swingedouw |
| 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 ; 11, no. 6 ; Nr. 11, no. 6 (2015-06-24), S.939-958 |
| Datensatznummer |
250117323
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| Publikation (Nr.) |
 copernicus.org/cp-11-939-2015.pdf |
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| Zusammenfassung |
| Reconstructions of past climate behavior often describe prominent anomalous
periods that are not necessarily captured in climate simulations. Here, we
illustrate the contrast between an interdecadal strong positive phase of the
winter Pacific/North American pattern (PNA) in the early 19th century
that is described by a PNA reconstruction based on tree rings from
northwestern North America, and a slight tendency towards negative winter
PNA anomalies during the same period in an ensemble of state-of-the-art
coupled climate simulations. Additionally, a pseudo-proxy investigation with
the same simulation ensemble allows for assessing the robustness of PNA
reconstructions using solely geophysical predictors from northwestern North
America for the last millennium. The reconstructed early 19th-century
positive PNA anomaly emerges as a potentially reliable feature, although the
pseudo-reconstructions are subject to a number of sources of uncertainty and
deficiencies highlighted especially at multidecadal and centennial
timescales. The pseudo-reconstructions demonstrate that the
early 19th-century discrepancy between reconstructed and simulated PNA
does not stem from the reconstruction process. Instead, reconstructed and
simulated features of the early 19th-century PNA can be reconciled by
interpreting the reconstructed evolution during this time as an expression
of internal climate variability, which is unlikely to be reproduced in its
exact temporal occurrence by a small ensemble of climate simulations.
However, firm attribution of the reconstructed PNA anomaly is hampered by
known limitations and deficiencies of coupled climate models and
uncertainties in the early 19th-century external forcing and background
climate state. |
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