We are currently working on a proposal for an imaging spectrometer for
Station Schneefernerhaus (UFS) located at an altitude of 2650 m above sea
level - 300 m below the top of the highest mountain of Germany, Zugspitze. The
picture below gives you an idea of the topography. Just below the
Schneefernerhaus is the Zugspitzplatt - the skiing area. The Zugspitzplatt is
surrounded by a chain of mountains. The digital elevation model was obtained
from 1 arc second resolution SRTM data.
Although the Schneefernerhaus is surrounded by mountains, its high altitude
allows a nearly unobstructed view to the South. Below is the view under
cloudless conditions as calculated by MYSTIC, using the above mentioned
digital elevation model.
To the North, the view is blocked by Zugspitze. To the South we find the
Zugspitzplatt which descends into the Reintal (SouthEast). A constant surface
albedo of 0.2 was assumed for this simulation. The wavelength was 550nm. The
sky shows the typical behaviour of a pure Rayleigh atmosphere without
aerosols: The horizon is much brighter than the overhead sky.
As we do not yet have our instrument, we have to live with simulations of how
a typical cloudy situation might be observed from Schneefernerhaus. Below is a
MYSTIC calculation of the
diurnal variation of the sky radiance at 550nm. The cumulus cloud field is the
output of a Large Eddy Simulation (LES). The cloud bottom was chosen at 3 km
for this simulation. The solar zenith angles were calculated for June 3. As in
the above calculation, a constant surface albedo of 0.2 was assumed. One can
watch how the clouds are illuminated from different sides during the course of
the day. In this case the viewing direction is South and the
image shows East (left) to West (right). In reality, the clouds usually don't
wait for the sun passing by, but this example illustrates nicely how the same
cloud would be seen over the course of the day. See also the course of the
cloud shadows on the ground. In fact, the actual weather on June 3 was more
like here - the picture was taken at
Zugspitzplatt around noon. Schneefernerhaus supposedly is to be found at
the other end of the cables.