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| Titel |
Snow depth data in the Alps versus SWE data in the Rocky Mountains |
| VerfasserIn |
C. Maurer, M. Hantel |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250023238
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| Zusammenfassung |
| Snow depth data in the Alps versus SWE data in
the Rocky Mountains *
Christian Maurer † and Michael Hantel †
12. January 2009
*Abstract of paper, submitted to EGU Meeting April 19-24, 2009, Vienna
†Research
platform Sensitive Mountain Limits of Snow and Vegetation, funded by the University of
ViennaThe duration of snow cover at climate stations of the Alps with respect to the mean
winter temperature over Europe has been investigated for the winters 1961-2000 (Hantel et
al., 2000; Hantel and Hirtl-Wielke, 2007). The snow duration n , expressed as the relative
number of days in a given winter, for which the snow depth exceeds a given treshold
(typically 2-10cm), was determined from routine measurements. In order to pool data of
stations with different elevation and horizontal position the "mountain-temperature" τ was
introduced. τ combines the regional mean temperature with the 3D coordinates of the
respective climate station in a regionally uniform manner (spatial Taylor expansion). The
profile n(τ) is a logistic curve; when fitted to the data of many winters its slope
(which is negative and adopts its minimum s0 at n = 0.5 ) represents the snow
duration–temperature sensitivity of the entire region. s0 for the Alps is about
- 0.3K -1 .
This has been an alarming figure; it calls for an independent check in other mountain
regions. Here we study, for the years 1961-2002, the SNOWTEL data for the Rocky
Mountains; these are automated daily measurements of snow water equivalent (SWE). Since
there is no unique conversion between SWE and snow depth we define independent tresholds
for the SWE data (typically 10-320 mm) and then apply the n(τ ) theory reviewed above to
the Rocky Mountain region. Surprisingly, despite the difference in the data type and climate
conditions the results are much the same (s0 = - 0.3K- 1 , within error limits),
implying that 1 degree warming should reduce the winter snow days by 30 percent;
further, s0 is independent upon the SWE treshold over more than an order of
magnitude.
These results support the hypothesis that the concept of relative snow duration yields a
robust sensitivity with respect to the large-scale regional temperature, no matter if the source
data are snow depth (the Alps) or snow weight (the Rocky Mountains). It appears that a
general behavior has emerged that governs different climate regions of the world in like
manner. |
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