rne 
st 
Infrared thermography is independent of light conditions but very 
sensitive to fog, clouds and any type of precipitation, which often 
confines the useable maximum flight altitudes and thus reduces the 
mapping capacity. 
5.1.6 Satellite information 
The information from LANDSAT-2 was of very good quality. The 
resolution was about 80 m which made it possible to identify different 
ice parameters, such as large ice floes and leads. The areal coverage 
was good enabling large-scale mapping for e.g. ice forecasting. 
There were, however, severe restrictions in the availability of the 
LANDSAT information. It was obtainable only 2-3 times every 18th 
day and only on request from NASA. The information was recorded on 
amgnetic tape on board the satellite and tapped when passing a 
receiving station. One further drawback of the satellites then 
used was the weather dependence and, as concerns the visual part, 
also the light dependence. 
The LANDSAT-2 provided information from four spectral channels 
(MSS) in the visual part of the electromagnetic spectrum. The MSS 
data gave the best information on ice concentration. 
5.1.7 Conclusions 
None of the tested sensors alone gave satisfactory mapping of all 
the ice parameters required. The FLAR and ODAR gave a general view 
of the ice fields, identifying major ice/water boundaries as vell 
as major areas of deformed ice. 
The SLAR gave much more details about the deformed ice fields and 
also identified more leads and fractures. Though it was not possible 
by any of the radars to distinguish open water from level ice 
directly from the graytones in the imagec, it appeared that open 
water areas could be located indirectly in SLAR pictures on the 
basis of location, shape; size and sharpness of edges. 
All the radar systems had a good areal coverage.