ATMOSPHERIC RADIOACTIVITY
ALONG THE 80TH MERIDIAN (WEST)
LUTHER B. LOCKHART, JR., ROBERT L. PATTERSON, JR.,
ALLEN W. SAUNDERS, JR., and ROBERT W. BLACK
U. S. Naval Research Laboratory, Washington, D. C,
ABSTRACT
Operation of the Naval Research Laboratory (NRL) 80th Meridian Air
Sampling Program, from May 1956 through December 1962, took place
during an interesting period in the nuclear age and the developmentof
nuclear weaponry and covered the nearly three-year moratorium on
nuclear testing as well as the episodes of intensive testing of highyield devices both before and after the moratorium. Data collected
during this program helped substantiate a number of concepts regarding atmospheric mixing processes and residence times of radioactive particulate matter in the atmosphere.
This paper summarizes measurements of the concentrations of
both gross beta activity and Sr activity inthe air at ground level along
the 80th meridian (west) during the period 1957 to 1962. More-detailed
results and interpretations are given for collections of radioactivity
made in 1962.
INTRODUCTION
At the time of inception of the 80th Meridian Air Sampling Program
in 1955, there were even more uncertainties than there are now in the
behavior of airborne nuclear-bomb debris. The concept of delayed deposition of stratospheric debris was in its infancy, and the seasonal
aspects of this deposition were unsuspected. No information was available on the extent of transequatorial migration of radioactive aerosols
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