RADIATION STANDARDS, INCLUDING FALLOUT
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is a discrepancy between the AEC estimate and that observed. However, in this case, the explanation lies not in incomplete ocean sampling, because you can double the value of 0.2 and not bring the inventory even close to 2.5 megacuries. It is either the fact that there
has not been as much added by the Soviet test, or the following explanation.
Placard 4 is a plot in which the North Pole lies on the left end of the
horizontal axis, the Equator is at the zero degree point and extends on
the right to 10° in the Southern Hemisphere. The vertical axis is
altitude in thousandsof feet. The heavy black line without a numerical label, identified as “tropopause,” represents the separation between
the troposphere below and the stratosphere above. It has a break
at approximately 30° N.
The solid and dashed Hinesare isolines of concentration of strontium
90 of Soviet 1961 debris. The highest concentration is at about 50,000
feet close to the North Pole. Near the Equator the values decrease and
rise to higher altitudes. But there has been considerable mixing
southward along the meridian, at which the stratospheric sampling
has taken place, from the point of injection at 75° N. virtually to the
Equator.In fact, a month or so later some short-lived isotopes from the Soviet
tests were observed in the stratosphere of southern Australia.
The inventory calculations above were based on this cross section.
One can, in very straightforward fashion, determine the amount of
Soviet 1961 strontium 90 in the atmosphere, assuming the concentration is the same around the circle of latitude as at the meridian of
sampling. Above 60,000 feet, the concentrations become smaller,
from the order of a hundred to less than 10 units. The dash lines
reflect the lack of complete data.
It looks like the aircraft are over the tops of the nuclear clouds
at. 70,000 feet. However, at two points, San Angelo, Tex., and Thule,
Greenland, we have obtained some balloon measurements. At San
Angelo, Tex., where air is filtered and equipment carried on a very
large plastic balloon, a large peak was found at 60,000 feet, corresponding to the aircraft maximum at the same altitude. This is
indicated by the horizontal line at 60,000 feet on the placard at San
Angelo, Tex.
.
At higher altitudes, the horizontal lines become shorter as the concentration decreases, At higher altitudes, the concentrations or the
lengths of the horizontal lines increase in length again. Thereis apparently another cloud at higher altitudes above 70,000 feet.
The same picture, more orless, takes place at Thule, Greenland,
where the peak concentration is slightly higher than that identified by
the Stardust aircraft flights but decreases at about 80,000 feet and
then increases again at 90,000 or 100,000 feet.
It is quite apparent, I think, that someof the larger Soviet weapons
went to much higheraltitudes than 70,000 feet, the ceiling of the Stardust aircraft sampling. For this reason, a satisfactory inventory of
the total Soviet debris is unavailable.
The next subject is the geographical distribution of strontium 90
fallout on placard 5. This is a map showingthe fallout in mid-1960in
millicuries of strontium 90 per square mile. Nowoneis discussing
thousandths of a curie of strontium 90 dispersed over a square mile of
86853 O—62—pt. 1——6
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