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| Titel |
The importance of glacier and forest change in hydrological climate-impact studies |
| VerfasserIn |
N. Köplin, B. Schädler, D. Viviroli, R. Weingartner |
| 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. 2 ; Nr. 17, no. 2 (2013-02-11), S.619-635 |
| Datensatznummer |
250017713
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| Publikation (Nr.) |
 copernicus.org/hess-17-619-2013.pdf |
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| Zusammenfassung |
| Changes in land cover alter the water balance components of a catchment, due
to strong interactions between soils, vegetation and the atmosphere.
Therefore, hydrological climate impact studies should also integrate
scenarios of associated land cover change. To reflect two severe
climate-induced changes in land cover, we applied scenarios of glacier
retreat and forest cover increase that were derived from the temperature
signals of the climate scenarios used in this study. The climate scenarios
were derived from ten regional climate models from the ENSEMBLES project.
Their respective temperature and precipitation changes between the scenario
period (2074–2095) and the control period (1984–2005) were used to run a
hydrological model. The relative importance of each of the three types of
scenarios (climate, glacier, forest) was assessed through an analysis of
variance (ANOVA). Altogether, 15 mountainous catchments in Switzerland were
analysed, exhibiting different degrees of glaciation during the control
period (0–51%) and different degrees of forest cover increase under
scenarios of change (12–55% of the catchment area). The results show
that even an extreme change in forest cover is negligible with respect to
changes in runoff, but it is crucial as soon as changes in evaporation or
soil moisture are concerned. For the latter two variables, the relative
impact of forest change is proportional to the magnitude of its change. For
changes that concern 35% of the catchment area or more, the effect of
forest change on summer evapotranspiration is equally or even more important
than the climate signal. For catchments with a glaciation of 10% or more
in the control period, the glacier retreat significantly determines summer
and annual runoff. The most important source of uncertainty in this study, though, is
the climate scenario and it is highly recommended to apply an
ensemble of climate scenarios in the impact studies. The results presented here
are valid for the climatic region they were tested for, i.e., a humid,
mid-latitude mountainous environment. They might be different for regions
where the evaporation is a major component of the water balance, for
example. Nevertheless, a hydrological climate-impact study that assesses the
additional impacts of forest and glacier change is new so far and provides
insight into the question whether or not it is necessary to account for land
cover changes as part of climate change impacts on hydrological systems. |
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