694
SESSION IIB DISCUSSION
device, Cadmium-113m (14-year half-life), which is a beta emitter,
was produced also in this shot. Because of this nuclide’s longer half-
life and more easily detected radiation, it may turn out to be of great
value in tracing Starfish debris. The ‘'*”Cd data must be corrected,
however, for the amount of this isotope of cadmium present as fis-
sion product. From the branching ratio* and the unclassified data on
yields for '3™Cdt, we have estimated a '!?"Cd/"Sr activity ratio in
thermonuclear fission of 0.003 to 1. This ratio is in good agreement
with data from a few samples measured from the northern hemisphere
which have no '%Ccd. In our samples we have found a ''?™cd/!%cq
ratio due to Starfish of about 0.2 to 1.
REITER: I should like to ask Dr. Newell how far up in the atmosphere he thinks hemispheric differences in circulation patterns can
be traced. He has mentioned that explosive warmings are less dramatic
in the southern than in the northern hemisphere. It has been my under-
standing that the antarctic stratosphere warms very quickly around
the equinoxes, whereas the arctic stratosphere may warm at various
dates, Data from the IGY suggest that the troposphere of the southern
hemisphere possesses a more zonal character of flow than that of
the northern hemisphere. How far up in the stratosphere are the same
differences in flow characteristics expected to be present? For the
northern hemisphere we have some rather interesting meteorologicalrocket-network data. Such data still are lacking for the southern hemisphere. Do the transport observations of radioactive debris give any
significant indication of hemispheric differences at higher stratospheric levels?
NEWELL: From the conventional radiosonde network in the northern hemisphere, we can compute standing- and transient~eddy transports up to about 25 mb (25 km) and can obtain approximate estimates
of the transient-eddy transports up to 10 mb (31 km). Although the
work reported to date refers to the IGY only, the Planetary Circulations Project is presently concerned with a study of the transports
which covers a five-year period. One of our former colleagues, Dr.
Obasi of the Nigerian Meteorological Service, has made a study of
momentum transports over the southern hemisphere for the IGY. His
work indicates that the data above 100 mb (16 km) are not adequate
for reliably defining the transports or for making comparisons between northern and southern hemispheres.
The meteorological-rocket-network data span the height range
of 30 to 60 km. With 12 stations in the northern hemisphere, we can
*From G. R. Crocker, Estimates of Fission Product Yields of a Thermonuclear Explosion, Report USNRDL-TR-642, U. 8. Naval Radiological Defense
Laboratory, Apr. 4, 1963.
tFrom A.C. Wahl, 14-Year 143mCd, J. Inorg. Nucl. Chem., 10: 1-3 (1959).