Open Session - SWISS GEOSCIENCE MEETINGs

have been used for trend analyses over a time period >100 years. A snow depth reconstruction with the method of Brown and
Braaten (1998) using daily new snow, temperature and precipitation as input variables performed well and made it possible
to analyse days with snow pack (Fig. 2).
The results show that the snow cover is varying substantially on seasonal and decadal time scales, which is in line with
Scherrer (2006). The analyses of the decadal new snow trends during the last 100 years shows unprecedented low new snow
sums in the winter seasons (DJF) of the 1990s. The 100 year trend of days with snow pack reveals a significant decrease for
stations below 800 m asl in the winter season (DJF) and for stations around 1800 m asl in the spring season (MAM). Similar
results were found for seasonal new snow sums. Finally the results of the trend analyses are discussed with respect to the
temperature trends.
REFERENCES
Brown, R.; Braaten, R.; 1998: Spatial and Temporal Variability of Canadian Monthly Snow Depths (1946-1995); Atmosphere
Ocean 36 (1), 37-54.
Scherrer, S.C.; 2006: Interannual climate variability in the European and Alpine region; Veröffentlichung Nr. 67 der
MeteoSchweiz, Zürich.
Figure 1. New snow sum series for Sils Maria (1798 m asl) 1864-2005
Figure 2. Days with snow pack based on reconstructed snow depth for Sils Maria (1798 m asl) 1864-2005.
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Evidence of warming in disturbed and undisturbed permafrost terrain at
Schafberg (Pontresina, Eastern Swiss Alps)
Zenklusen Mutter Evelyn*, Phillips Marcia*, Blanchet Juliette*
WSL, Institute for Snow and Avalanche Research SLF, CH-7260 Davos, Switzerland (zenklusen@slf.ch)
Both climate and human influences in the form of technical structures may alter ground temperatures in mountain permafrost
soils (Phillips 2006). In 1996 several boreholes were drilled into the permafrost of the Muot da Barba Peider (Schafberg)
ridge above Pontresina in the Eastern Swiss Alps. This study investigates and compares the ground temperatures measured
in two of these boreholes, B1 and B2.
The boreholes are located 50m apart at 2960m asl in a NW oriented steep scree slope and are instrumented with 10 thermistors
between 0.5m and 17.5m depth. Both locations are very similar from a climatological and geological point of view. The
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Symposium 6: Apply! Snow, ice and Permafrost Science + Geomorphology