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| Titel |
Climate impact on floods: changes in high flows in Sweden in the past and the future (1911–2100) |
| VerfasserIn |
B. Arheimer, Göran Lindström |
| 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. 2 ; Nr. 19, no. 2 (2015-02-04), S.771-784 |
| Datensatznummer |
250120621
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| Publikation (Nr.) |
 copernicus.org/hess-19-771-2015.pdf |
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| Zusammenfassung |
| There is an ongoing discussion whether floods occur more frequently today
than in the past, and whether they will increase in number and magnitude in
the future. To explore this issue in Sweden, we merged observed time series
for the past century from 69 gauging sites throughout the country
(450 000 km2) with high-resolution dynamic model projections of the
upcoming century. The results show that the changes in annual maximum daily
flows in Sweden oscillate between dry and wet periods but exhibit no
significant trend over the past 100 years. Temperature was found to be the
strongest climate driver of changes in river high flows, which are related
primarily to snowmelt in Sweden. Annual daily high flows may decrease by on
average −1% per decade in the future, mainly due to lower peaks from
snowmelt in the spring (−2% per decade) as a result of higher
temperatures and a shorter snow season. In contrast, autumn flows may
increase by +3% per decade due to more intense rainfall. This
indicates a shift in flood-generating processes in the future, with greater
influence of rain-fed floods. Changes in climate may have a more significant
impact on some specific rivers than on the average for the whole country. Our
results suggest that the temporal pattern in future daily high flow in some
catchments will shift in time, with spring floods in the northern–central
part of Sweden occurring about 1 month earlier than today. High flows in the
southern part of the country may become more frequent. Moreover, the current
boundary between snow-driven floods in northern–central Sweden and
rain-driven floods in the south may move toward higher latitudes due to less
snow accumulation in the south and at low altitudes. The findings also
indicate a tendency in observations toward the modeled projections for timing
of daily high flows over the last 25 years. Uncertainties related to both the
observed data and the complex model chain of climate impact assessments in
hydrology are discussed. |
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