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| Titel |
Lidar snow cover studies on glaciers in the Ötztal Alps (Austria): comparison with snow depths calculated from GPR measurements |
| VerfasserIn |
K. Helfricht, M. Kuhn, M. Keuschnig, A. Heilig |
| 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. 1 ; Nr. 8, no. 1 (2014-01-07), S.41-57 |
| Datensatznummer |
250116005
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| Publikation (Nr.) |
 copernicus.org/tc-8-41-2014.pdf |
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| Zusammenfassung |
| The storage of water within the seasonal snow cover is a substantial
source of runoff in high mountain catchments. Information about the
spatial distribution of snow accumulation is necessary for calibration
and validation of hydro-meteorological models. Generally, only a small
number of precipitation measurements deliver precipitation input for
modelling in mountain areas. The spatial interpolation and
extrapolation of measurements of precipitation is still difficult.
Multi-temporal application of lidar
techniques from aircraft, so-called airborne laser scanning (ALS),
provides surface elevations changes even in inaccessible
terrain.
These ALS surface elevation changes can be used to derive changes in snow depths of the mountain snow cover
for seasonal or subseasonal time periods.
However, since glacier surfaces are not static over time, ablation, densification of snow,
densification of firn and ice flow contribute to surface elevation changes.
ALS-derived surface elevation changes were compared to snow depths
derived from 35.4 km of ground penetrating radar (GPR) profiles on four glaciers.
With this combination of two different data acquisitions, it is possible
to evaluate the effect of the summation of these processes on ALS-derived snow depth maps in the high
alpine region of the Ötztal Alps (Austria).
A Landsat 5 Thematic Mapper image was used to distinguish
between snow covered area and bare ice areas of the glaciers at the end of the ablation season.
In typical accumulation areas, ALS surface elevation changes
differ from snow depths calculated from GPR measurements
by −0.4 m on average with a mean standard deviation of 0.34 m.
Differences between ALS surface elevation changes and GPR derived snow depths are small along the profiles
conducted in areas of bare ice. In these areas, the mean absolute difference of ALS surface
elevation changes and GPR snow depths is 0.004 m with a standard deviation of 0.27 m.
This study presents a systematic approach to analyze deviations from ALS generated snow depth maps
to ground truth measurements on four different glaciers.
We could show that ALS can be an important and reliable data source for the spatial distribution
of snow depths for most parts of the here investigated glaciers.
However, within accumulation areas, just utilizing ALS data may lead to
systematic underestimation of total snow depth distribution. |
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