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| Titel |
Soil erosion and organic carbon export by wet snow avalanches |
| VerfasserIn |
O. Korup, C. Rixen |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 8, no. 2 ; Nr. 8, no. 2 (2014-04-14), S.651-658 |
| Datensatznummer |
250116092
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| Publikation (Nr.) |
 copernicus.org/tc-8-651-2014.pdf |
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| Zusammenfassung |
| Many mountain belts sustain prolonged snow cover for parts of the year,
although enquiries into rates of erosion in these landscapes have focused
almost exclusively on the snow-free periods. This raises the question of
whether annual snow cover contributes significantly to modulating rates of
erosion in high-relief terrain. In this context, the sudden release of snow
avalanches is a frequent and potentially relevant process, judging from the
physical damage to subalpine forest ecosystems, and the amount of debris
contained in avalanche deposits. To quantitatively constrain this visual
impression and to expand the sparse literature, we sampled sediment
concentrations of n = 28 river-spanning snow-avalanche deposits (snow
bridges) in the area around Davos, eastern Swiss Alps, and inferred an
orders-of-magnitude variability in specific fine sediment and organic carbon
yields (1.8 to 830 t km−2 yr−1, and 0.04 to 131 t C km−2 yr−1,
respectively). A Monte Carlo simulation demonstrates that, with a
minimum of free parameters, such variability is inherent to the geometric
scaling used for computing specific yields. Moreover, the widely applied
method of linearly extrapolating plot scale sample data may be prone to
substantial under- or overestimates. A comparison of our inferred yields
with previously published work demonstrates the relevance of wet snow
avalanches as prominent agents of soil erosion and transporters of
biogeochemical constituents to mountain rivers. Given that a number of snow
bridges persisted below the insulating debris cover well into the summer
months, snow-avalanche deposits also contribute to regulating in-channel
sediment and organic debris storage on seasonal timescales. Finally, our
results underline the potential shortcomings of neglecting erosional
processes in the winter and spring months in mountainous terrain subjected
to prominent snow cover. |
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