摘要：It could be shown that the normalised difference Vegetation index (NDVI) can be automatically processed
for mountainous terrain characterised by steep slopes
and high cloud coverage throughout the year. The
quality of the data can be improved if the variables for
the atmospheric correction (water vapor, ozone and
pressure) are taken from a finer grid resolution and if
the actual aerosol optical depth is used. However, even
under these improved concitions, the magnitude of the
NDVI would differ but the behavior and shape of the
graphs in general would remain. Die upward trend of
the winter NDVI in the years 1995–1998 is significant
for the altitudinal levels 1001–1500 m and 501–1000 m.
To be able to find out more about the snow covered
areas at these heights, reference was made to the air
temperatures of Zürich, Engelberg and Santis. Thus,
we were able to show that the increase of NDVI at
lower elevations during the wintertime was linked to
decreasing snow covered areas. In elevations above
2000 m, a slight increase in the summer NDVI could
be detected but the linear trend is not significant. An
explanation for this could not be given due to missing
meta-data, such as the extent of the snow covered area.
In conclusion, it may be said that there is a good correlation
between the air temperature and the NDVI, but
that the quality of the precipitation database does not
allow for a correlation to be made between precipitation and the NDVI.
