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| Titel |
Influence of solar forcing, climate variability and modes of low-frequency atmospheric variability on summer floods in Switzerland |
| VerfasserIn |
J. C. Peña, L. Schulte, A. Badoux, M. Barriendos, A. Barrera-Escoda |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 19, no. 9 ; Nr. 19, no. 9 (2015-09-10), S.3807-3827 |
| Datensatznummer |
250120804
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| Publikation (Nr.) |
 copernicus.org/hess-19-3807-2015.pdf |
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| Zusammenfassung |
| The higher frequency of severe flood events in Switzerland in recent decades
has given fresh impetus to the study of flood patterns and their possible
forcing mechanisms, particularly in mountain environments. This paper
presents a new index of summer flood damage that considers severe and
catastrophic summer floods in Switzerland between 1800 and 2009, and
explores the influence of external forcings on flood frequencies. In
addition, links between floods and low-frequency atmospheric variability
patterns are examined. The flood damage index provides evidence that the
1817–1851, 1881–1927, 1977–1990 and 2005–present flood clusters occur mostly
in phase with palaeoclimate proxies. The cross-spectral analysis documents
that the periodicities detected in the coherency and phase spectra of 11
(Schwabe cycle) and 104 years (Gleissberg cycle) are related to a high
frequency of flooding and solar activity minima, whereas the 22-year
cyclicity detected (Hale cycle) is associated with solar activity maxima and
a decrease in flood frequency. The analysis of low-frequency atmospheric
variability modes shows that Switzerland lies close to the border of the
principal summer mode. The Swiss river catchments situated on the centre and
southern flank of the Alps are affected by atmospherically unstable areas
defined by the positive phase of the pattern, while those basins located in
the northern slope of the Alps are predominantly associated with the
negative phase of the pattern. Furthermore, a change in the low-frequency
atmospheric variability pattern related to the major floods occurred over
the period from 1800 to 2009; the summer principal mode persists in the negative
phase during the last cool pulses of the Little Ice Age (1817–1851 and
1881–1927 flood clusters), whereas the positive phases of the mode prevail
during the warmer climate of the last 4 decades (flood clusters from 1977 to
present). |
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