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| Titel |
A millennial multi-proxy reconstruction of summer PDSI for Southern South America |
| VerfasserIn |
É. Boucher, J. Guiot, E. Chapron |
| 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 ; 7, no. 3 ; Nr. 7, no. 3 (2011-08-30), S.957-974 |
| Datensatznummer |
250004621
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| Publikation (Nr.) |
 copernicus.org/cp-7-957-2011.pdf |
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| Zusammenfassung |
| We present the first spatially explicit field reconstruction of the summer
(DJF) Palmer Drought Severity Index (PDSI) for the Southern Hemisphere. Our
multi-proxy reconstruction focuses on Southern South America (SSA, south of
20° S) and is based on a novel spectral analogue method that aims at
reconstructing low PDSI frequencies independently from higher frequencies.
The analysis of past regimes and trends in extreme wet spells and droughts
reveals considerable geographical and temporal variations over the last
millennium in SSA. Although recent changes are in some cases notorious, most
were not exceptional at the scale of the last thousand years. Our
reconstruction highlights that low frequency water availability fluctuations
in Patagonia were generally in antiphase with the rest of the subcontinent.
Providing the fact that modern patterns of changes are transferable to the
past, we show that such antiphases within SSA's hydroclimate could be
attributed to the spatially contrasted response of summer PDSI to the
Antarctic Oscillation (AAO). However, El Niño Southern Oscillation
(ENSO) and Pacific Decadal Oscillation (PDO) signals are also embedded
within the PDSI series during the 20th century. All these
ocean-atmospheric forcings acted synergically, but the dominant influence
appeared highly compartmentalized through space, highlighting clear AAO-
(e.g. South Patagonia) and ENSO- (e.g. the Pampas) dominated regions. Our
results therefore emphasize the complexity of water-availability
fluctuations in SSA and their important dependence on external
ocean-atmospheric forcings. |
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