RADIOACTIVITY IN PRECIPITATION
561
that crossed station 6 was becoming less intense, and, even though the
storm itself was not dissipating, the total-beta concentration and
rainfall-rate profiles show the characteristic of a beta-concentration
maximum and a rainfall-rate maximum occurring together, similar to
those profiles of dissipating cells of the previous day. Theintensity
center crossed station 4, and, even though it was decreasing, the
inverse relation of beta-concentration minimum and rainfall-rate
maximum wasin evidence. In a comparison of the beta at stations 1, 4,
and 6 during the times of rainfall-rate maximums, Figs. 34 to 36 show
that
the
values at the three stations are quite close to each other
despite the differing relations of the beta concentrations to the rainfallrate maximumsat stations 4 and 6.
The cell intensified again after it had passed station 4. The orientation of the leading edge of the storm was suchthat precipitation
began almost concurrently at stations 5 and 7, The resulting rainfallsample cross sections and echo-intensity and radar-storm-top profiles
in Figs. 31, 32, 35, and 36 are quite similar, The intensity center
crossed station 5, where the maximum in rainfall rate was greater and
the beta-concentration minimum was less than values at station 7, The
radar storm tops over both stations were at 35,000 ft. Thus at this
time the cell was confined to the troposphere, although it had maxi-
mized before crossing the stations. That the more intense area crossed
station 5 is reflected in the rainfall-rate cross section. The rainfall
rate at this station was almost twice that of station 7.
The northern portion of this cell crossed station 3, and, even
though the rainfall rate was inversely related to the total beta concentration, Fig. 34 shows that the intense rainfall persisted for 8 min,
during which time four samples were collected. These samples were
possibly related to storm development that took place south of station 3,
but the rainfall-sample profiles of this station were similar to those at
stations 5 and 7 for this cell,
The section of the cell which crossed station 2 was north of the
echo-intensity maximum; Fig. 34 indicates the minimum beta concentration not associated with rainfall maximum, At this time the entire
cell was intensifying and the structure in the area of station 2 was
complex in that the echo-intensity and rainfall-rate maximums coincided with an increase in beta concentration from the previous sample,
with the maximum in the beta concentration occurring with a sharp
decline in the rainfall rate.
The cell that crossed the southern portion of the network had
attained maximum radar tops of 44,000 ft before entering the network,
which decreased and then intensified again over the network, The cell
moved from the network still with its maximum intensity of 48 db.
Figure 29 shows that the maximum echo intensity passed two miles
north of station 8, directly over stations 9 and 10, The resulting