RADIOACTIVITY IN PRECIPITATION
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Fig. 12—Precipitation pattern (solid lines) and total-beta-concentration
pattern (dashed lines) for Apr. 23, 1964, Precipitation is in tenths of
inches of rainfall, and total beta concentration is in picocuries per liter.
The ratio of particulate to dissolved beta activity at the leading
edge decreased with time, and the observed minimum occurred at the
leading edge. This could have been due to fewer dust particles being
carried aloft by the diminishing low-level convergence in advance of
the dissipating cell.
ANALYSIS OF STORM OF MAY 9
At 1800Z on May 9, a quasi-stationary surface front was positioned as shown in Fig. 13. Winds were southeasterly at the surface
over Oklahoma, veering west-—southwesterly up to the tropopause.
Afternoon squall-line activity began about 100 nautical miles west of
the collection network and moved eastward at about 20 knots. By 1900
CST the squall line entered the collection network. At this time the line
was oriented northeast—southwest and was about 100 miles long and
about 30 miles wide. The southern portion crossed the collection net-
work at about 20 knots. The individual cells had an eastward movement.
The storm structure that passed over the network was quite
complex, Figure 14 shows the storm position and intensities of the
major cells, Most of the collectors had multiple sample collections
(see Table 1; samples containing rainfall from more than one cell are
indicated by an asterisk). Samples from the northwest portion of the
network, where the rainfall was generally light, contained peripheral
rains from several small cells.