302
FEELY AND BAZAN
movement of the debris was probably controlled by seasonal changes in
the coefficients of turbulent exchange within the tropical stratosphere.
INTRODUCTION
The moratorium on nuclear-weapons tests, which had begun in
November 1958, was ended in September 1961 when the U.S.S.R. began
a series of atmospheric tests of nuclear devices. After the end of the
moratorium and before the 1963 treaty banning atmospheric weapons
tests went into effect, there were three major series of tests which
injected large amounts of nuclear debris into the stratosphere. These
were test series conducted by the U.S.S.R. during September to No-
vember 1961 and August to December 1962 and by the United States
during April to November 1962 (Operation Dominic I). Debris from
these test series was sampled by the High Altitude Balloon Sampling
Program.'? The combination of data from this program with data from
other programs of stratospheric sampling, such as Project Star Dust,
sponsored by the Defense Atomic Support Agency, permits the delinea-
tion of the stratospheric distribution of nuclear debris from these test
series and a description of the changes that have occurredin that
distribution during the past three years.
In this discussion we will pay special attention to information con-
cerning the initial vertical distribution of debris injected into the
stratosphere and information concerning the factors that influence the
later movement of the debris within the stratosphere. We will note
evidence that suggests that almost all debris injected into the polar
stratosphere, even by weapons of very high yield, has tended to stabilize in the lower polar stratosphere, below 70,000 ft. We will also note
evidence concerning the seasonal dependence of rates of transfer of
debris from one region of the stratosphere to another. We have found
no evidence that any organized circulation of the stratosphere exists
which plays a major role in the movement of debris within the stratoSphere. Therefore our discussion is based on the assumption that
turbulent exchange plays the major role in the transfer of debris within
the stratosphere, although organized circulation and particle settling
probably also play less important roles.
CORRELATION OF BALLOON AND WU-2 DATA
Both the balloon and the WU-2 samplers have been calibrated.
Nevertheless it is desirable that empirical data be used to substantiate
the validity of their intercalibration. Since mid-1962 the collection of
samples by the balloon program has been performed ataltitudes of
approximately 65,000, 80,000, 90,000, and 105,000 ft. Asa result, during