Fróðskaparrit - 01.01.2002, Blaðsíða 99

ARKTISKA FJALLAVEÐRIÐ í 2000 Á SORNFELLI
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The location of the Sornfelli
meteorological station
Several Faroese mountain tops reach 700 m
asl., which is well into the arctic zone.
However, only the 749 m high Sornfelli
mountain offers infrastructure useful for
the establishment and operation of a mete-
orological station. The Sornfelli mountain
holds a Danish military facility, Flyvesta-
tion Thorshavn, on the summit, with road
access and power supply, including support
from the military personnel. This in combi-
nation with its central location on the island
Streymoy, and the existence of two operat-
ing meteorological stations located at dif-
ferent altitudes in the landscape below
Sornfelli (Fig. 2), led to the location of the
mountain meteorological station at this par-
ticular mountain.
The summit of Sornfelli is a 200 m wide
plateau, delimited by steep up to 200 m
high headwalls. The plateau dips 8° south
southeast (Fig. 3), and is covered by a di-
amict, with scattered boulders and an up to
2 m deep, coarse-grained soil cover above
the basalt bedrock. The surface is dominat-
ed by active periglacial patterned ground,
and has moss vegetation in a few parts. The
mountaintop was severely weathered dur-
ing the last glaciation, when it was a
nunatak (O. Humlum, pers. comm.), thus
explaining the relatively deep soil cover.
The meteorological station is located at 722
m asl., centrally in the southern part of the
plateau (Fig. 3), minimizing the lee effect
from the military installations in the north-
ern end of the plateau, and preventing most
of the edge wind effects glong the head-
walls.
Challenges to the Sornfelli
meteorological station
Previous attempts to run a meteorological
station on Sornfelli using a conventional
mast with fixed instruments, recording
wind with cup anemometers have failed
primarily due to icing and destructive wind
forces (Military personnel Sornfelli,
pers.comm.). Sornfelli as a mountain is rel-
atively frequently struck by lightning, so
1961-1990 pcriod Akraberg liglitliousc Vágar airport Tórshavn
Altitude of station (m asl) 101 84 54
Mean annual air temperature (2 m) 6.4 6.0 6.5
Warmest month (Aug) 10.0 10.4 10.5
Coldest month (Jan) 3.8 2.7 3.4
Annual precipitation (mm) 884 1555 1284
Wind spced (10 min average) m/s 8.1 5.9
Most frequent wind direction W W
Table 1. Climatological parameters observed in the latest World Meteorologicai Organisation (WMO)
standard normal period 1961-1990 at the Faroe Islands based on synoptical stations (Cappelen and Laursen,
1998). Precipitation was at Vágar airport only measured from 1988-1997. All other observations at Vágar
airport were during the period 1968-1997. The wind speed obsen’ations at Akraberg werefrom 1962-1990.
Cappelen and Laursen (1998) do not report wind measurements at Vágar airport.