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| Titel |
How unusual was late 20th century El Niño-Southern Oscillation (ENSO)? Assessing evidence from tree-ring, coral, ice-core and documentary palaeoarchives, A.D. 1525-2002 |
| VerfasserIn |
J. L. Gergis, A. M. Fowler |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7340
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| Digitales Dokument |
URL |
| Erschienen |
In: 1st Alexander von Humboldt International Conference ; Nr. 6 (2006-02-01), S.173-179 |
| Datensatznummer |
250003255
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| Publikation (Nr.) |
 copernicus.org/adgeo-6-173-2006.pdf |
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| Zusammenfassung |
| Multiple proxy records (tree-ring, coral, ice and documentary) were examined
to isolate ENSO signals associated with both phases of the phenomenon for
the period A.D. 1525-2002. To avoid making large-scale inferences from
single proxy analysis, regional signals were aggregated into a network of
high-resolution records, revealing large-scale trends in the frequency,
magnitude and duration of pre-instrumental ENSO using novel applications of
percentile analysis. Here we use the newly introduced coupled
ocean-atmosphere ENSO index (CEI) as a baseline for the calibration of proxy
records. The reconstruction revealed 83 extreme or very strong ENSO episodes
since A.D. 1525, expanding considerably on existing ENSO event chronologies.
Significantly, excerpts of the most comprehensive list of La Niña events
complied to date are presented, indicating peak activity during the
16th to mid 17th and 20th centuries. Although extreme events
are seen throughout the 478-year reconstruction, 43% of the extreme ENSO
events noted since A.D. 1525 occur during the 20th century, with an
obvious bias towards enhanced El Niño conditions in recent decades. Of
the total number of extreme event years reconstructed, 30% of all
reconstructed ENSO event years occur post-1940 alone suggesting that recent
ENSO variability appears anomalous in the context of the past five
centuries. |
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