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| Titel |
Snow accumulation of a high alpine catchment derived from LiDAR measurements |
| VerfasserIn |
K. Helfricht, J. Schöber, B. Seiser, A. Fischer, J. Stötter  , M. Kuhn |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7340
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| Digitales Dokument |
URL |
| Erschienen |
In: Proceedings of the 15th Workshop on Large-scale Hydrological Modelling ; Nr. 32 (2012-12-11), S.31-39 |
| Datensatznummer |
250017322
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| Publikation (Nr.) |
 copernicus.org/adgeo-32-31-2012.pdf |
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| Zusammenfassung |
The spatial distribution of snow accumulation substantially affects the
seasonal course of water storage and runoff generation in high mountain
catchments. Whereas the areal extent of snow cover can be recorded by
satellite data, spatial distribution of snow depth and hence snow water
equivalent (SWE) is difficult to measure on catchment scale. In this study we
present the application of airborne LiDAR (Light Detecting And Ranging) data
to extract snow depths and accumulation distribution in an alpine catchment.
Airborne LiDAR measurements were performed in a glacierized catchment in the
Ötztal Alps at the beginning and the end of three accumulation seasons. The
resulting digital elevation models (DEMs) were used to calculate surface
elevation changes throughout the winter season. These surface elevation
changes were primarily referred to as snow depths and are discussed
concerning measured precipitation and the spatial characteristics of the
accumulation distribution in glacierized and unglacierized areas. To
determine the redistribution of catchment precipitation, snow depths were
converted into SWE using a simple regression model. Snow accumulation
gradients and snow redistribution were evaluated for 100 m elevation bands.
Mean surface elevation changes of the whole catchment ranges from 1.97 m to
2.65 m within the analyzed accumulation seasons. By analyzing the
distribution of the snow depths, elevation dependent patterns were obtained
as a function of the topography in terms of aspect and slope. The high
resolution DEMs show clearly the higher variation of snow depths in rough
unglacierized areas compared to snow depths on smooth glacier surfaces. Mean
snow depths in glacierized areas are higher than in unglacierized areas.
Maximum mean snow depths of 100 m elevation bands are found between 2900 m
and 3000 m a.s.l. in unglacierized areas and between 2800 m and
2900 m a.s.l. in glacierized areas, respectively. Calculated accumulation
gradients range from 8% to 13% per 100 m elevation band in the
observed catchment. Elevation distribution of accumulation calculated by
applying these seasonal gradients in comparison to elevation distribution of
SWE obtained from airborne laser scanning (ALS) data show the total
redistribution of snow from higher to lower elevation bands.
Revealing both, information about the spatial distribution of snow depths and
hence the volume of the snow pack, ALS data are an important source for
extensive snow accumulation measurements in high alpine catchments. These
information about the spatial characteristics of snow distribution are
crucial for calibrating hydrological models in order to realistically compute
temporal runoff generation by snow melt. |
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