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- 1207 - 
Vessel "Gauss" repeatedly crossing the trail of the dumping 
tanker is very well visible in the thermal infrared channel 
of the images. With adequate contrast enhancement, this se- 
condary image is superimposed to the picture calculated. This 
serves to a direct mapping of the course and path of "Gauss" 
at the time when the continuous measurements were taken. Sec- 
tions of images from the low altitude surveys, when using op- 
timal contrast enhancement by "function memory" programs, re- 
veal a high degree of plasticity, with a very detailed fine 
structure of the fresh dumping trail. With these data, further 
investigations into the dynamics of the mixing process of waste 
solutions with the sea water may be interesting. Results of 
such studies are in turn needed for the purpose of international 
conventions on dumping. A program is available for micro-densi- 
tometry of the grey value distribution following an arbitrarily 
selected curved line in a suitably generated image. This can 
be used for simple and easy construction of profiles for corre- 
lation with continuous chemical measurements in sea water. Sub- 
tracting one channel from the other with subsequent display of 
the grey value distribution in the form of colored equidensites 
is well suited for enhancing the visible contrasts and con- 
structing a semi-quantitative surface distribution pattern of 
iron hydroxide particulates, especially when applied to the 
images of the later stages of diffusion of the waste solution 
trails, some hours after dumping into the sea. 
At an early phase in the digital image processing it has been 
observed that spectral differences occur in the trail on the 
same picture. During one of the first low altitude (552 m) 
overpasses two "puffs" were recorded: the younger one (closer 
to the moving waste solution tanker) is more green, while the 
older puff is distinctively more red in its spectral appear- 
ance, This could be interpreted as a sign for the increasing 
oxidation of green Fe(II) to red Fe(III) in the sea water 
shortly after deposition. However, it might have been possi- 
ble that by mere coincidence one of the puffs was more deeply 
submersed and thus superposed by a thicker layer of green 
North Sea water.