732
PELLETIER, WHIPPLE, AND WEDLICK
>
and
24
OZ
4
z>
qa
~ =
7
|
Fig. 4—Specific ac..vity of
daily rainfall vs. rainfall
amounts for Leningrad,
ci
|
England (C, 1956 and 19357), and
~
<
~ 2
a
0.1
1
2
||
|
i
|
3.4
5
10
20
.
.
.
.
_
U.S.S.R. (0, dates unknown),
Kjeller, Norway (A, 1956 to
1959).
330
DAILY RAINFALL, MM
according to daily rainfall, and then plotting the averages on an arbitrary scale. That these data show exponential cleansing of radioactivity from the atmosphere is shown in Fig. 5. The product of the
radioactivity concentration and the amountof rainfall is the total deposition. These products were computed from the data in Fig. 4, and they
were plotted against rainfall in Fig. 5. The data from England and Norway could be fitted with the model having values of b equal to 0.76 and
1.27, respectively. The fit was unambiguous. The data from Russia
were too scattered for a quantitative measurement of b.
Figures 6 and 7 show more-direct evidence that the model might
be applied to other locations and times. Figure 6 showsa plot of the
ratio of deposition to the air concentration as a function of rainfall
for two sites in Great Britain!® during the period August 1962 through
April 1963. The points can be joined by a curve having the form of the
model with b equal to 0.11. It should be pointed out that from August to
February fresh fallout predominated in this area. Figure? shows similar data for Kjeller, Norway, from January through September 1959.
These points can also be fitted with the model having a value of b equal
to 0.11. Furthermore, these data from Norway permit evaluation of the
term “a,” which is included in the model to account for dry fallout onto
z
We
or
a
Ee Zz
.
oe
.
wg
Fig. 5—Daily deposition vs.
daily rainfall amounts for Len-
ingrad, U.S.S.R. (Lb, dates unknown), England (C, 1956 and
1957), and Kjeller, Norway (A,
1956 to 1959).
25
Q >
Sz
a
—
7
|
VE
-
0.5
5
4
—
a
~ =
28
<&
T
a
0
4
5
1
5
:
;
10
15
DAILY RAINFALL, MM
Z
q
q
20