
TARGET DETECTION
137
strength comparable to or weaker than that returned
from the sea waves which are prevalent in the area in
which the growlers are commonly found.
Theories relating to the effects of high temperature
gradients in the immediate vicinity of the growler and
also to the re-radiation characteristic of the ice have
not proved conclusive.
2 In areas where growlers are to be expected, radar
should not be relied upon to give adequate or even
any warning of their presence, especially at night or in
poor visibility. Speed and the visual lookout should be
set with this in mind.
The best use of radar under these circumstances is:
(a)