RADIOACTIVITY IN PRECIPITATION
565
had a similar profile but had greater beta-concentration values, For
dissipating cells, the beta-activity maximums occur with the rainfall-
rate
maximums
(stations
5,
7,
and 10 in the storm of May 9 and
stations 9 and 10 in the storm of May 10) along with a peak in the
ratios of particulate to dissolved beta activity, possibly because of
entrainment aloft on the back sides of the storms. The profiles of beta
concentration collected at stations to the right and left of intensity
centers are Similar to those at the center for both the mature cells
and the dissipating cells, but, because the rainfall rates are less in-
tense, the evaporation effect is more pronouncedin the initial and the
final collections.
REFERENCES
1. 5. J. Hall and E. H. Klehr, Severe Convective Storms and the Stratospheric
Scavenging of Radioactive Particles, First Progress Report (Contract Num-
ber AT-(40-1)-3083), University of Oklahoma, 1963.
2. R. A. Huff, Study of Rainout of Radioactivity in Illinois,
Second Progress
Report (Contract Number AT(11-1)-1199), Illinois State Water Survey, 1964.