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| Titel |
Deducing high-altitude precipitation from glacier mass balance measurements |
| VerfasserIn |
Rianne H. Giesen, Walter W. Immerzeel, Niko Wanders |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250129669
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| Publikation (Nr.) |
 EGU/EGU2016-9812.pdf |
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| Zusammenfassung |
| The spatial distribution of precipitation in mountainous terrain is generally not well known
due to underrepresentation of gauge observations at higher elevations. Precipitation tends to
increase with elevation, but since observations are mainly performed in the valleys, the
vertical precipitation gradient cannot be deduced from these measurements. Furthermore,
the spatial resolution of gridded meteorological data is often too coarse to resolve
individual mountain chains. Still, a reliable estimate of high-elevation precipitation is
required for many hydrological applications. We present a method to determine the
vertical precipitation gradient in mountainous terrain, making use of glacier mass
balance observations. These measurements have the advantage that they provide a
basin-wide precipitation estimate at high elevations. The precipitation gradient is
adjusted until the solid precipitation over the glacier area combined with the calculated
melt gives the measured annual glacier mass balance. Results for the glacierized
regions in Central Europe and Scandinavia reveal spatially coherent patterns, with
predominantly positive precipitation gradients ranging from -4 to +28 % (100 m)−1. In some
regions, precipitation amounts at high elevations are up to four times as large as
in the valleys. A comparison of the modelled winter precipitation with observed
snow accumulation on glaciers shows a good agreement. Precipitation measured at
the few high-altitude meteorological stations is generally lower than our estimate,
which may result from precipitation undercatch. Our findings will improve the
precipitation forcing for glacier modelling and hydrological studies in mountainous terrain. |
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