494
LOCKHART, PATTERSON, SAUNDERS, AND BLACK
of nuclear weaponry, At its initial stage the concept of a stratospheric
residence time for radioactive debris was highly speculative, and
seasonal variations in the deposition from this reservoir were not apparent, primarily because of the disadvantageous scheduling of nuclear
tests. The temporary moratorium on nuclear testing following several
extensive series of high-yield nuclear tests permitted the unambiguous
verification by many investigators of seasonal changes in the deposition rate of stratospherically stored debris over the entire northern
hemisphere. It also permitted determination of the effect of the latitude
of injection on the residence time of radioactivity in the stratosphere
with shorter residence periods observed for the arctic stratosphere.
During this period and also after the renewed testing had begun in the
arctic region, the lack of an effective mechanism by which particulate
matter could be transferred across the equator inthe lower atmosphere
was again noted.
With the conduct of full-scale testing of high-yield nuclear devices
in both the arctic and tropic regions in 1962, followed by what is pre-
sumed will be a more permanent moratorium on testing, the condition
of the stratospheric inventory and prospects for observations during
the coming years are equivalent to those existing in the period 1959 to
1961, The multiplicity of sources is again causing difficulty in making
quantitative interpretations of atmospheric mixing or transport processes, although for a while there should be an ample quantity of radio-~
activity available for many interesting studies,
REFERENCES
1. L. B. Lockhart, Jr., R. A. Baus, and I. H. Blifford, Jr., Atmospheric Radioactivity Along the 80th Meridian, 1956, Report NRL-
4965, U. S. Naval Research Laboratory. July 1957.
2, L. B, Lockhart, Jr., Information on Fallout, in The Nature of Radioactive Fallout and Its Effects on Man, Hearings Before the Special Subcommittee on Radiation of the Joint Committee on Atomic
Energy, Congress of the United States, 85th Congress, 1st Session,
Vol. 1, pp. 650-673, U. S. Government Printing Office, Washington,
D, C,, 1957.
3. R. A. Baus,
P. R.
Gustafson,
R. L. Patterson, Jr.,
and
A.
W.
Saunders, Jr., Procedure for the Sequential Radiochemical Analy-
sis of Strontium, Yttrium, Cesium, Cerium. and Bismuth in Air-
filter Collections, Report NRL-Memo-758, U. S, Naval Research
Laboratory, November 1957,
4. L. B. Lockhart, Jr., R. A. Baus, and I. H. Blifford, Jr., Fission-
product Radioactivity in the Air Along the 80th Meridian, January —
June 1957, Report NRL-5041, U. S. Naval Research Laboratory,
November 1957. See also Tellus, 11(1): 83-90 (1959).
5. R. A. Baus, R. L. Patterson, Jr., A. W. Saunders, Jr., and L. B.
Lockhart, Jr., Radiochemical Analysis of Air-filter Samples Collected During 1957, Report NRL-5239, U. S. Naval Research Laboratory, December 1958.