Chapter 5
CONCLUSIONS
5el
ABSORPTION
Severe absorption of vertically transmitted high-frequency
radio signals was observed to the west of all multi-megaton shots,
starting about 2 hours after the detonation and lasting several hours.
This absorption is presumed to have been due to ionization caused by
radioactive material carried westward by high-level winds. It was not
observed during Operation IVY, because no ionosphere recorder was
situated at a location where this effect may have occurred.
This newly observed phenomenon is of great significance as it
points to the possibility of a prolonged and widespread ionospheric
comaunications blackout in the event that a number of cities were hit
by megaton weapons during a period of a few hours.
502
SPORADIC-E EFFECTS
Definite sporadic-E£ effects were noted at Rongerix, 150 miles
to the east of the test site. From the time that echoes were first
observable there until at least two hours after each major shot, the
maximum frequency of sporadic-E returns was considerably higher than
normal. During this period, these echoes also evidenced an unusual
amount of "spread" or scattering and multiple-level reflections,
Sporadic-E returns are usually considered to be the result of turbulence
and are frequently associated with ionospheric storms.
5e3
F2 LAYER EFFECTS
For shots of megaton range, an effect on the F2-layer was ob-
served which was similar to that first found following Shot Mike of
Operation IVY, The apparent cause of this phenomenon is the largescale convection resulting from the conversion of blast-wave energy
into heat in the upper atmosphere. The nature of the effect varies
from shot to shot, presumably because of different atmospheric conditions or yields.
i)
SECRET