Global Change Abstracts The Swiss Contribution - SCNAT

Global Change Abstracts – The Swiss Contribution | Cryosphere
important information on former and recent
permafrost conditions. Two different methods
were applied in one study area (Turtmann Valley,
Swiss Alps) in order to compare their suitability
in assessing rockglacier activity. The comparison
of geomorphological mapping and photogrammetric
monitoring demonstrated a good accordance,
especially on a regional scale. On a local
scale, some differences in delimitation of the
landforms as well as in the degree of activity were
found. One reason for the observed differences
is the qualitative character of geomorphological
mapping resulting from the variable suitability
of single parameters and combinations thereof in
the determination of rockglacier activity. Based
on these results, geomorphological mapping of
rockglaciers can be improved by data from photogrammetric
monitoring. Therefore, at best the
two methods are combined when analysing former
and present permafrost distribution.
Earth Surface Processes and Landforms, 2007, V32,
N12, OCT 30, pp 1747-1758.
08.1-231
Influence of different digital terrain models
(DTMs)on alpine permafrost modeling
Salzmann N, Gruber S, Hugentobler M, Hölzle M
Switzerland
Modelling , Cryology / Glaciology , Instruments &
Instrumentation
The thawing of alpine permafrost due to changes
in atmospheric conditions can have a severe impact,
e.g., on the stability of rock walls. The energy
balance model, PERMEBAL, was developed
in order to simulate the changes and distribution
of ground surface temperature (GST) in complex
high-mountain topography. In such environments,
the occurrence of permafrost depends greatly on
the topography, and thus, the digital terrain model
(DTM) is an important input of PERMEBAL. This
study investigates the influence of the DTM on the
modeling of the GST. For this purpose, PERMEBAL
was run with six different DTMs. Five of the six
DTMs are based on the same base data, but were
generated using different interpolators. To ensure
that only the topographic effect on the GST is calculated,
the snow module was turned off and uniform
conditions were assumed for the whole test
area. The analyses showed that the majority of the
deviations between the different model outputs
related to a reference DTM had only small differences
of up to 1 K, and only a few pixels deviated
more than 1 K. However, we also observed that the
use of different interpolators for the generation of
a DTM can result in large deviations of the model
output. These deviations were mainly found at
125
topographically complex locations such as ridges
and foot of slopes.
Environmental Modeling Assessment, 2007, V12,
N4, NOV, pp 303-313.
08.1-232
Modeling the effect of snow and ice on the
global environmental fate and long-range
transport potential of semivolatile organic
compounds
Stocker J, Scheringer M, Wegmann F,
Hungerbühler K
Switzerland
Modelling , Cryology / Glaciology , Geochemistry &
Geophysics
Snow and ice have been implemented in a global
multimedia box model to investigate the influence
of these media on the environmental fate and longrange
transport (LRT) of sernivolatile organic compounds
(SOCs). Investigated compounds include
HCB, PC1328, PCB180, PBDE47, PBDE209, alpha-
HCH, and dacthal. In low latitudes, snow acts as a
transfer medium taking up chemicals from air and
releasing them to water or soil during snowmelt. In
high latitudes, snow and ice shield water, soil, and
vegetation from chemical deposition. In the model
version including snow and ice (scenario 2), the mass
of chemicals in soil in high latitudes is between 27%
(HCB) and 97% (alpha-HCH) of the mass calculated
with the model version without snow and ice (scenario
1). Amounts in Arctic seawater in scenario 2
are 8% (alpha- HCH) to 21% (dacthal) of the amounts
obtained in scenario 1. For all investigated chemicals
except alpha-HCH, presence of snow and ice in the
model increases the concentration in air by a factor
of 2(HCB)to 10(PBDE209). Because of reduced net deposition
to snow-covered surfaces in high latitudes,
LRT to the Arctic is reduced for most chemicals
whereas transport to the south is more pronounced
than in scenario 1 (“southward shift”). The presence
of snow and ice thus considerably changes the environmental
fate of SOCs.
Environmental Science Technology, 2007, V41,
N17, SEP 1, pp 6192-6198.
08.1-233
Climate warming revealed by englacial temperatures
at Col du Dome (4250 m, Mont Blanc
area)
Vincent C, Le Meur E, Six D, Possenti P, Lefebvre E,
Funk M
France, Switzerland
Meteorology & Atmospheric Sciences , Cryology /
Glaciology
Temperatures were measured in two deep boreholes
drilled at the same location in the ice at Col