870
_
_MADSHUS AND STROMME
Apart from exceptional occurrences such as local squalls, stations
situated near each other in a small but not too mountainous area record
only slight differences in the amount of precipitation, Stations situated
on the leeside of mountains or mountain ranges, however, commonly
record considerably less precipitation than stations situated where the
geological formations force moist air upward. Where moist air is
forced upward because of topographical conditions, the precipitation
usually increases with the height above the sea. These conditions very
often occur in regions in Western and Northern Norway where stations
are situated rather close to each other but have very different precipitation rates. Observations from single stations are therefore not
representative for their districts, and in these studies the average
precipitation rates from several stations in and around thedistrict
in question were used. The precipitation rate in the district from which
the dairy receives its milk was therefore estimated as the average
probable precipitation rate measured by meteorological stations in and
around the district. (If any error is made by this method of calculation,
the same error will be made the following years, Other differences
from the true precipitation will also be reduced.)
Figures 6 to 8 show the specific concentration of '*’Cs in spring
milk vs, the precipitation in the preceding year. In Fig. 6 the average
precipitation for 1959, 1960, and 1961 has beenused, whereas in Figs. 7
and 8 the precipitation in 1962 and 1963, respectively, has been used.
600
T
yl
500 +
T
3S
7
OF
.
.
4b
400 +
x
ele
.
= 300+
4+
s
Zz
=
S200
7
.
100 [-
. ° °
~
—
were
‘
*
.
‘Se
:
0
0
.
*
1000
2000
ZONE 1
ob
-
4
-
_
e
4
-
.
°
*e *,
°
°
_
34°.
e
Ra
°
*”r.-
e
10006
2000
o
=
—
;
°°
™
*
{
3000 0
4
;
*
ee
1
ZONE 2
.
*.
-
.
ae
a? ’
offs
3000 0
4
ee
e
1
°
-*
7°
4k
oo
-*
T
_|
1000
2000
ZONE 3
PRECIPITATION, MM
Fig. 6—-Cesium-137 in milk in the spring of 1962 vs. the average precipitation for 1959, 1960, and 1961.
3000