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| Titel |
On the need for bias correction in regional climate scenarios to assess climate change impacts on river runoff |
| VerfasserIn |
M. J. Muerth, B. Gauvin St-Denis, S. Ricard, J. A. Velázquez, J. Schmid, M. Minville, D. Caya, D. Chaumont, R. Ludwig, R. Turcotte |
| 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 ; 17, no. 3 ; Nr. 17, no. 3 (2013-03-19), S.1189-1204 |
| Datensatznummer |
250018832
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| Publikation (Nr.) |
 copernicus.org/hess-17-1189-2013.pdf |
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| Zusammenfassung |
In climate change impact research, the assessment of future river runoff as
well as the catchment-scale water balance is impeded by different sources of
modeling uncertainty. Some research has already been done in order to
quantify the uncertainty of climate projections originating from the climate
models and the downscaling techniques, as well as from the internal
variability evaluated from climate model member ensembles. Yet, the use of
hydrological models adds another layer of uncertainty. Within the QBic3
project (Québec–Bavarian International Collaboration on Climate Change),
the relative contributions to the overall uncertainty from the whole model
chain (from global climate models to water management models) are
investigated using an ensemble of multiple climate and hydrological models.
Although there are many options to downscale global climate projections to
the regional scale, recent impact studies tend to use regional climate
models (RCMs). One reason for that is that the physical coherence between
atmospheric and land-surface variables is preserved. The coherence between
temperature and precipitation is of particular interest in hydrology.
However, the regional climate model outputs often are biased compared to the
observed climatology of a given region. Therefore, biases in those outputs
are often corrected to facilitate the reproduction of historic runoff
conditions when used in hydrological models, even if those corrections alter
the relationship between temperature and precipitation. So, as bias
correction may affect the consistency between RCM output variables, the use
of correction techniques and even the use of (biased) climate model data
itself is sometimes disputed among scientists. For these reasons, the effect
of bias correction on simulated runoff regimes and the relative change in
selected runoff indicators is explored. If it affects the conclusion of
climate change analysis in hydrology, we should consider it as a source of
uncertainty. If not, the application of bias correction methods is either
unnecessary to obtain the change signal in hydro-climatic projections, or
safe to use for the production of present and future river runoff scenarios
as it does not alter the change signal.
The results of the present paper highlight the analysis of daily runoff
simulated with four different hydrological models in two natural-flow
catchments, driven by different regional climate models for a reference and
a future period. As expected, bias correction of climate model outputs is
important for the reproduction of the runoff regime of the past, regardless
of the hydrological model used. Then again, its impact on the relative
change of flow indicators between reference and future periods is weak for
most indicators, with the exception of the timing of the spring flood peak.
Still, our results indicate that the impact of bias correction on runoff
indicators increases with bias in the climate simulations. |
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