Frequency and intensity of palaeofloods at the interface of Atlantic and Mediterranean climate domains
Mediterranean climatic influences was explored by studying a lake sequence (Lake Foréant) of the Western European Alps. High-resolution sedimentological and geochemical analysis revealed 171 event layers, 168 of which result from past flood events over the last millennium. The layer thickness was us...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-02-01
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| Series: | Climate of the Past |
| Online Access: | http://www.clim-past.net/12/299/2016/cp-12-299-2016.pdf |
| Summary: | Mediterranean climatic influences was explored by studying a lake sequence
(Lake Foréant) of the Western European Alps. High-resolution
sedimentological and geochemical analysis revealed 171 event layers, 168 of
which result from past flood events over the last millennium. The layer
thickness was used as a proxy of intensity of past floods. Because the
Foréant palaeoflood record is in agreement with the documented
variability of historical floods resulting from local and mesoscale,
summer-to-autumn convective events, it is assumed to highlight changes in
flood frequency and intensity related to such events typical of both Atlantic
(local events) and Mediterranean (mesoscale events) climatic influences.
Comparing the Foréant record with other Atlantic-influenced and
Mediterranean-influenced regional flood records highlights a common feature
in all flood patterns that is a higher flood frequency during the cold period
of the Little Ice Age (LIA, AD 1300–1900). In contrast, high-intensity flood
events are apparent during both the cold LIA and the warm Medieval Climate
Anomaly (MCA, AD 950–1250). However, there is a tendency towards higher
frequencies of high-intensity flood events during the warm MCA. The MCA
extremes could mean that under the global warming scenario, we might see an
increase in intensity (not in frequency). However, the flood frequency and
intensity in the course of the 20th century warming trend did not change
significantly. Uncertainties in future evolution of flood intensity lie in
the interpretation of the lack of 20th century extremes (transition or
stable?) and the different climate forcing factors between the two periods
(greenhouse gases vs. solar and/or volcanic eruptions). |
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| ISSN: | 1814-9324 1814-9332 |