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10 20 31 10 2028 10 20 31 10 20 30 10 20 31 10 20 30 10 20 31 10 20 31 10 20 30
JAN.
FEB.
MAR.
APR.
MAY
JUN,
JUL.
AUG.
SEP.
1963
Fig, 1—Time series of comparison
shorter period fallout fluctuations.
the smoothed cyclone-index series.
lines are five-day mean gross beta
between derived cyclone index and
Upper part of diagram is a plot of
In the lower part: the connected
activity, and the smooth line is
representative of mean morthly fallout values. Vertical arrows show
correspondence between rapia cyclone-index drops and fluctuations of
surface-fallout intensity upon the mean monthly distribution. Plotted
numbers associated with the arrows give the time in days after the
center date of the period over which the drop occurred. Solid bars
represent time increment over the period of index decrease. Values of
[100(C ;—C2)/At computed during rapid decreases of cyclone index are
given in Table 1.
figure shows that an irregular fallout fluctuation of short duration is
superimposed upon the seasonal oscillation as determined from the
monthly averages. Because of the large number of observations that
determine these five-day means and the relatively small variance
between the individual measurements, even relatively small fluctuations of fallout intensity become statistically significant.
Figure 2
shows that a very pronounced increase in mean fallout characterized
the spring of 1963 and that a spring peak also occurred in 1964, The
1964 maximum is in agreement with a distinct spring fallout maximum’