ATMOSPHERIC TRANSPORT PROCESSES LEADING TO
RADIOACTIVE FALLOUT OVER THE UNITED STATES
IN NOVEMBER 1962
ELMAR R. REITER and JERRY D. MAHLMAN
Colorado State University, Fort Collins,*Colorado
ABSTRACT
Radioactive fallout in excess of 320 pc/m? of air was observed over
the South Central United States Nov. 24 to 27, 1962. Atmospheric transport processes leading to these abnormally high values of fallout were
studied in detail. It was estimated that 0.6 x 10" metric tons of air
were involved in the rapid sinking process that transported air from
the tropopause level to the ground in a matter of approximately two
days. Wet washout processes also removed some radioactive debris
from the atmosphere.
INTRODUCTION
It has been established by a number of case studies’ ® that atmo-
Spheric motions, especially in the jet-stream region, are capable of
rapidly transporting downward radioactive debris from the tropopause
or the lower stratosphere to the ground.
The purposes of the study reported in this paper wereto (1) arrive
at quantitative estimates of the efficiency of such transport processes
in the removal of stratospheric debris and (2) derive, if possible, fore-
casting procedures for stratospheric fallout based upon dynamic considerations. These objectives were achieved by a detailed analysis of
a
case of strong radioactive fallout over the South Central United
States which occurred Nov. 24 to 27, 1962 (see Fig. 1), The motion of
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