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| Titel |
How catchment characteristics determine hydrological sensitivity to climate change in a mountainous environment |
| VerfasserIn |
Nina Köplin, Daniel Viviroli, Bruno Schädler, Rolf Weingartner |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250034524
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| Zusammenfassung |
| The anticipated climate change in Switzerland will result in changing precipitation
patterns and increasing temperatures during the first half of the 21st century (OcCC
2007). These changes will have an impact on the hydrological systems, too, in
particular in mountainous regions. The objective of our study is to determine those
catchments that exhibit sensitivity towards a change in climate, and to identify specific
catchment characteristics causing this sensitivity. Both issues will be addressed
in the framework of the joint research project “Climate Change in Switzerland –
Hydrology” (CCHydro) which was initiated by the Federal Office for the Environment
(FOEN).
In the present study, the hydrological modelling system PREVAH
(Precipitation-Runoff-EVAporation-HRU related model, Viviroli et al. 2009a) is used to
examine mesoscale catchments in Switzerland. It is a semi-distributed and conceptual yet
process-oriented model run on the basis of hourly meteorological input, and at a spatial
resolution of 500 x 500 m2. This spatial and temporal resolution is a necessary prerequisite to
meet the high degree of heterogeneity of mountainous environments. Where measured
discharge is available, catchments were successfully calibrated both for standard and flood
conditions using an iterative search algorithm designed to maximize objectivity of the
calibration procedure (Viviroli et al. 2009b). The parameter values thus obtained were
transferred to ungauged catchments subsequently. For this, a regionalisation scheme was used
(Viviroli et al. 2009c) to arrive at a comprehensive set of model parameters for the entire area
of Switzerland.
A total of 17 Regional Climate Models (RCMs) from the ENSEMBLES-project
(Hewitt & Griggs 2004) were interpolated to meteorological station locations at the
Institute for Atmospheric and Climate Science (IAC) at ETH Zurich (Bosshard et al.
2009) using the Delta Approach (Prudhomme et al. 2002). The Delta Change Signal
was calculated for the period 2021 to 2050 relative to the reference period 1976 to
2005. The annual cycle of the Delta Change is added to the observed time series to
generate a set of climate scenarios with which the regionalised catchment models are
forced.
To check the climate scenarios for hydrologic plausibility, they are applied
to six test regions first, each of them representing a natural landscape unit of the
Northern Alps. The results of this plausibility tests are evaluated, and the climate
scenarios will be applied to approximately 200 mesoscale catchments with an average
area of 150 km2 and a range of 30 to 2000 km2 to be able to specify causal (i.e.
process-based) relationships between climate sensitivity and specific catchment
characteristics.
References
Bosshard, T.; Ewen, T.; Kotlarski, S. & Schär, C. (2009): The annual cycle of the climate
change signal - An improved method for use in impact studies, Geophysical Research
Abstracts, Vol. 11, EGU2009-7095.
OcCC (2007): Climate Change and Switzerland 2050. Impacts on Environment, Society
and Economy. Bern: OcCC.
Hewitt, C. D. & Griggs, D. J. (2004): Ensembles-Based Predictions of Climate Changes
and Their Impacts, Eos Trans. AGU, 85(52), doi: 10.1029/2004EO520005.
Prudhomme, C.; Reynard, N. & Crooks, S. (2002): Downscaling of global climate models
for flood frequency analysis: where are we now? Hydrol. Proc. 16, 1137–1150.
Viviroli, D.; Zappa, M.; Gurtz, J. & Weingartner, R. (2009a): An introduction to the
hydrological modelling system PREVAH and its pre- and post-processing tools.
Environmental Modelling & Software, 24(10), 1209–1222.
Viviroli, D.; Zappa, M.; Schwanbeck, J.; Gurtz, J. & Weingartner, R. (2009b): Continuous
simulation for flood estimation in ungauged mesoscale catchments of Switzerland – Part
I: Modelling framework and calibration results. Journal of Hydrology, 377(1–2),
191–207.
Viviroli, D.; Mittelbach, H.; Gurtz, J. & Weingartner, R. (2009c): Continuous simulation
for flood estimation in ungauged mesoscale catchments of Switzerland – Part II: Parameter
regionalisation and flood estimation results. Journal of Hydrology, 377(1–2), 208–225. |
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