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FEELY AND BAZAN
was injected and that subSequent sampling along any meridian should
give a representative cross section of the atmosphere. Thus, although
we must remember the limitations on the accuracy of the distributions
we measure and the stratospheric burdens of *Sr we calculate from
them, our estimates of the burden should generally be accurate to
within 25%.
The stratospheric distributions of "Sr calculated from a combina-
tion of balloon and WU-2 data are shownin Figs. 10 to 13. The distribu-
tion during January through April 1962 (Fig. 10) reveals the presence
of fairly high *°Sr concentrations in the layer between the tropopause
and 70,000 ft in the northern hemisphere. The concentrations of °°Sr
in this layer which can be attributed to pre-1961 weapons tests were
approximately equal to the total *°Sr concentrations in the same region
in the southern hemisphere. The remaining **Sr was produced by the
1961 Soviet tests. It is noteworthy that in spite of the very high yields
of some of the devices tested during that series, the injected debris
was contained almost completely in the lower stratosphere. Of course,
as we have previously stated, representative concentrations of the
debris from these high-yield weapons were not present in the sampling
corridor at the time.
_
The distribution of *Sr during May to August 1962, presented in
the lower half of Fig. 10, shows the effects in the northern polar strato-
Sphere of the debris from the very high yield weapons and in the
tropical stratosphere of the debris from the 1962 United States tests.
The appearance of the debris from the high-yieid weapons caused an
increase in the concentrations of *Sr in the 60,000- to 100,000-ft layer
in the polar stratosphere but not enough of an increase to change our
opinion that comparatively little debris had been injected above
70,000 ft. The concentrations of "Sr indicated in the tropical strato-
sphere
are actually quite uncertain. Sampling in the
region below
70,000 ft was not intensive enough to ensure its representativeness
during this period of weapons testing. The concentrations shown in the
region above 70,000 ft are conjectural since debris from the United
States tests had not yet reached either San Angelo or Mildura in quantity
and no sampling was performed within the upper tropical strato-
sphere where this debris had been injected.
The *Sr distributions during September and October 1962 and
November and December 1962 are shown in Fig. 11. Both of the indi-
cated distributions are subject to relatively large errors because the
1962 U.S.S.R. tests were in progress during both intervals and even
the debris from the earlier United States Dominic I series was apparently still not uniformly distributed in the zonal direction. The
distributions indicated in the upper stratosphere, above 70,000 ft, and
in the entire tropical stratosphere are quite uncertain.