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surrounding waters. Instead for hummock areas, warming is much 
slower and their emissivity is always lower than the surround- 
ing tidal water. For quantitative temperature values, it is 
possible with the scanner to "slice" its signal, obtaining ab- 
solute values for surface temperature in the prefixed range 
(169 to 20? C). 
  
  
Water Dynamics 
From the observations of the frequency analyses (in fig. 2 
flights no. 3 and no. 4) one sees exactly how the incoming water 
flows through the many small and short channels which branch 
from the main canal; this phenomenon is surveyable by its di- 
rection and the effect of wake. 
Since in fig. 2, flight 1, a trace of such a geometric ar- 
rangement remains, it is evident that during the out going tide, 
the water does not flow in the same channels and direction as 
for the incoming, but that it flows through the main canal. If 
the water during ebb tide would follow the same course, we would 
find a bottom drift even in the opposite direction. 
Even if we could hypothesize a return flow for the same en- 
trance, such a hypothesis would suggest a flow rate much less 
than that of the incoming tide. Therefore the out going dynamic 
action does not present itself. Direct measurements do not con- 
firm such a hypothesis but that the out going flow rate is us- 
ually faster than that of the incoming. Taking into considera- 
tion wake varation, it is also possible to derive an indication 
of the surface speed of tidal diffusion. 
Bottom morphology 
Thermal imagery used in frequency analyses can even pro- 
vide information about principal features of the bottom mor- 
phology. 
During the flight over the area, the level of the water 
under tidal effect is increased more than one meter causing a 
diminution of those areas of land rising above the water with 
a gradual submersion of the lower hummock areas, in spite of