RADIATION STANDARDS, INCLUDING FALLOUT
79
In the Southern Hemisphere, the curve labeled “Santiago, Chile,”
showsdefinite evidence of a spring maximum in 1959 and a suggestion
that the sametrend is taking place in 1960 by the upward trendin the
curve.
This placard contains the latest data available for Santiago,
Chile. The peak is delayed a little more than one might expect, but
the fact that there is a seasonal trend is quite clear. At Argonne
National Laboratory, one finds a definite peak in the spring of 1960
and a suggestion of another peakin the spring of 1961.
Hereis a case where the Northern Hemisphere is not more heavily
contaminated than the Southern Hemisphere, and one finds the expected seasonal variation in the Southern Hemisphere.
The next placard, No. 10, shows the cesium 137 air concentration in
Argonne, Ill. The air concentration of cesium 137 permits one to
view the latest available fallout information. Most of the other longlived radionuclides do not. extend beyond about February of 1962.
The horizontal axis is the month of the year, and the vertical axis
is the air conceniration. The uppermost curve is the 1958-59 fallout
from the October 1958 U.S.S.R. test series. For this curve the first
month, October, is October 1958, and the last month, on the right, is
September 1959. We have seen previously that there was a definite
peak in the spring of 1959, and that is again shown by the uppermost.
curve.
In 1960-61 the total fallout—the lowermost curve derives from all
test series—had decreased by about a factor of 10 from 1959 because
of the test. moratorium and there were no new large-scale injections.
A peak appears in this curve, displaced by a month or two from the
maximum in 1959.
The fallout in 1962 attributed to the 1961 Soviet tests is shown
by the middle curve. It is incomplete, extending only through May
of 1962. In the early months, from October 1961 to about January
or February 1962, the levels of fallout are about the same as October
1958 through February 1959. Values are a little higher or lower in
one place or another. After February it looks like the levels of fallout are considerably lower than they were in 1959.
This may seem little bit strange in view of the fact that the an-
nounced yields called for 25 megatons to have been iniected in 1961
and only 12.5 to 15 megatons injected in 1958, both by the Soviet
Union. Straight extrapolation would require the fallout. to be higher
m. 1962 by a factor of 2. but apparently the fact that the clouds stabilized at higher altitudes and the possibility that the weather conditrons were not exactly the same this year as they were in 1959 apparently have contributed to make our spring fallout up to this point not
as heavy as we would expect. it by the simple extrapolation if the
myection numbersare correct.
_ I think T have used my time. I have a few other placards to show,
if you are interested in any predictions of fallout, of events which
would be of current interest.
Representative Prick. I think you should goon.
Dr. Maca. MayI please?
_ For the Prediction Panel and because of current interest, I would
like to make some estimates of fallout for injections made into three
places into the stratosphere.
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