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| Titel |
Climate change impacts on the seasonality and generation processes of floods – projections and uncertainties for catchments with mixed snowmelt/rainfall regimes |
| VerfasserIn |
K. Vormoor, D. Lawrence, M. Heistermann, A. Bronstert |
| 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 (2015-02-12), S.913-931 |
| Datensatznummer |
250120630
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| Publikation (Nr.) |
 copernicus.org/hess-19-913-2015.pdf |
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| Zusammenfassung |
| Climate change is likely to impact the seasonality and generation processes
of floods in the Nordic countries, which has direct implications for flood
risk assessment, design flood estimation, and hydropower production
management. Using a multi-model/multi-parameter approach to simulate daily
discharge for a reference (1961–1990) and a future (2071–2099) period, we
analysed the projected changes in flood seasonality and generation processes
in six catchments with mixed snowmelt/rainfall regimes under the current
climate in Norway. The multi-model/multi-parameter ensemble consists of
(i) eight combinations of global and regional climate models, (ii) two methods
for adjusting the climate model output to the catchment scale, and (iii) one
conceptual hydrological model with 25 calibrated parameter sets. Results
indicate that autumn/winter events become more frequent in all catchments
considered, which leads to an intensification of the current autumn/winter
flood regime for the coastal catchments, a reduction of the dominance of
spring/summer flood regimes in a high-mountain catchment, and a possible
systematic shift in the current flood regimes from spring/summer to
autumn/winter in the two catchments located in northern and south-eastern
Norway. The changes in flood regimes result from increasing event magnitudes
or frequencies, or a combination of both during autumn and winter. Changes
towards more dominant autumn/winter events correspond to an increasing
relevance of rainfall as a flood generating process (FGP) which is most
pronounced in those catchments with the largest shifts in flood seasonality.
Here, rainfall replaces snowmelt as the dominant FGP primarily due to
increasing temperature. We further analysed the ensemble components in
contributing to overall uncertainty in the projected changes and found that
the climate projections and the methods for downscaling or bias correction
tend to be the largest contributors. The relative role of hydrological
parameter uncertainty, however, is highest for those catchments showing the
largest changes in flood seasonality, which confirms the lack of robustness
in hydrological model parameterization for simulations under transient
hydrometeorological conditions. |
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