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WIND-INDUCED MICROCLIMATIC DIFFERENCES DETECTED FROM
THERMAL SCANNER DATA
Wilfried Nübler
Geographisches Institut I der Universitat Freiburg
Introduction
The climatological interpretation of thermal scanner data is a
long and intricate story. Since more advanced remote sensing
methods have been available, the solution of climatological
questions has always been looked upon as one possible and pro-
mising application of the new techniques [Mattsson 1967, Lorenz
1973a]. It is intricate, in that there is still a good deal of
controversy on whether at all, or to what degree, remotely
sensed data of the earth's surface can be useful for the clima-
tologist [Lorenz 1973b]. This is especially apparent in the
case of small scale or micro- and mesoclimatological studies.
However, certain applications at the global level, e.g. cloud
cover monitoring, are now standard methods [Lenhart 1978].
The main reason for this reserved attitude still prevalent among
climatologists is not a technical but a principal one: Thermal
scanning means recording the radiation emitted by the earth's
surface, while the climatologist is concerned with the air layer
above this surface. Although it is evident that the boundary
layer of the atmoghere is influenced by the underlying surface,
interrelationships are so complex that unequivocal interpretation
is, in general, not possible.
It is the purpose of this paper to demonstrate that under certain
conditions microclimatic differences can definitely be deduced
from thermal scanner data. The possibilities and limitations of
tracing cold air in thermal images were covered earlier [Nubler
1978]. This paper concentrates on two examples of the effect of
wind action as seen in thermal images.
Material and methods
All material referred to is taken from the data obtained from
the German Remote Sensing Project (Deutsches Flugzeugmefpro-