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| Titel |
Evaluation of future hydrological cycle under climate change scenarios in a mesoscale Alpine watershed of Italy |
| VerfasserIn |
B. Groppelli, A. Soncini, D. Bocchiola, R. Rosso |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 11, no. 6 ; Nr. 11, no. 6 (2011-06-21), S.1769-1785 |
| Datensatznummer |
250009495
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| Publikation (Nr.) |
 copernicus.org/nhess-11-1769-2011.pdf |
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| Zusammenfassung |
| We investigate future (2045–2054) hydrological cycle of the snow fed Oglio
(≈1800 km2) Alpine watershed in Northern Italy. A Stochastic
Space Random Cascade (SSRC) approach is used to downscale future
precipitation from three general circulation models, GCMs (PCM, CCSM3, and
HadCM3) available within the IPCC's data base and chosen for this purpose based
upon previous studies. We then downscale temperature output from the GCMs to
obtain temperature fields for the area. We also consider a projected
scenario based upon trends locally observed in former studies, LOC scenario.
Then, we feed the downscaled fields to a minimal hydrological model to build
future hydrological scenarios. We provide projected flow duration curves and
selected flow descriptors, giving indication of expected modified (against
control run for 1990–1999) regime of low flows and droughts and flood
hazard, and thus evaluate modified peak floods regime through indexed flood. We
then assess the degree of uncertainty, or spread, of the projected water
resources scenarios by feeding the hydrological model with ensembles
projections consistent with our deterministic (GCMs + LOC) scenarios, and we
evaluate the significance of the projected flow variables against those
observed in the control run. The climate scenarios from the adopted GCMs differ
greatly from one another with respect to projected precipitation amount and
temperature regimes, and so do the projected hydrological scenarios. A
relatively good agreement is found upon prospective shrinkage and shorter
duration of the seasonal snow cover due to increased temperature patterns,
and upon prospective increase of hydrological losses, i.e. evapotranspiration,
for the same reason. However, precipitation patterns are less consistent,
because HadCM3 and PCM models project noticeably increased precipitation for
2045–2054, whereas CCSM3 provides decreased precipitation patterns therein. The
LOC scenario instead displays unchanged precipitation. The ensemble simulations
indicate that several projected flow variables under the considered
scenarios are significantly different from their control run counterparts,
and also that snow cover seems to significantly decrease in duration and depth.
The proposed hydrological scenarios eventually provide a what-if analysis, giving a
broad view of the possible expected impacts of climate change within the
Italian Alps, necessary to trigger the discussion about future adaptation
strategies. |
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