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Titel |
Model simulations of the modulating effect of the snow cover in a rain-on-snow event |
VerfasserIn |
N. Wever, T. Jonas, C. Fierz, M. Lehning |
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 ; 18, no. 11 ; Nr. 18, no. 11 (2014-11-26), S.4657-4669 |
Datensatznummer |
250120533
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Publikation (Nr.) |
copernicus.org/hess-18-4657-2014.pdf |
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Zusammenfassung |
In October 2011, the Swiss Alps underwent a marked rain-on-snow (ROS) event when
a large snowfall on 8 and 9 October was followed by intense rain
on 10 October. This resulted in severe flooding in some parts of Switzerland.
Model simulations were carried out for 14 meteorological stations in two
affected regions of the Swiss Alps using the detailed physics-based snowpack
model SNOWPACK. We also conducted an ensemble sensitivity study, in which
repeated simulations for a specific station were done with meteorological
forcing and rainfall from other stations. This allowed the quantification of
the contribution of rainfall, snow melt and liquid water storage on
generating snowpack runoff. In the simulations, the snowpack produced runoff
about 4–6 h after rainfall started, and total snowpack runoff became
higher than total rainfall after about 11–13 h. These values appeared to
be strongly dependent on snow depth, rainfall and melt rates. Deeper snow
covers had more storage potential and could absorb all rain and meltwater in
the first hours, whereas the snowpack runoff from shallow snow covers reacts
much more quickly. However, the simulated snowpack runoff rates exceeded the
rainfall intensities in both snow depth classes. In addition to snow melt,
the water released due to the reduction of liquid water storage
contributed to excess snowpack runoff. This effect appears to be stronger for
deeper snow covers and likely results from structural changes to the snowpack
due to settling and wet snow metamorphism. These results are specifically
valid for the point scale simulations performed in this study and for ROS events on relatively fresh snow. |
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