GLOBAL DISTRIBUTION OF TRITIUM
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Jan.— Dec.
Jan.— Dec.
jan.— Dec.
1962
1963
1964
Fig. 6—Tritium fallout in South Continental Asia,
In 1964 the usual spring peak appeared but at a lower level than
in 1963. Comparative mean peak values are given below for several
continental mid-latitude sites:
Station
Vienna, Austria
Chicago, Il.
Flagstaff, Ariz.
Teheran, Iran
1963
4837
2955
1332
4450
(March through July)
(March through June)
(January and March’
(April)
1964
2674
2648
965
3020
(March through July)
(March through June)
(January and March)
(April)
It is apparent that tritium concentration in precipitation began
trending downward in 1964. The rate of decrease of tritium
interval 1963—1964 is seen to be less than the rate of decrease
corresponding interval 1959-1960. It appears to be comparable
decrease in the interval 1960—1961. This is illustratedin Fig. 10,
in the
in the
to the
which
presents the respective decay slopes. The difference is thought to be
due to the respective altitudes of injection involved in the 1958 and the
1961-1962 test series.
Throughout the development and the apparent decay of the 1963
tritium peak, the concentrations of tritium in precipitation at sites
influenced by oceanic air have been consistently below the concentra-
tions observed at continental locations in the same latitude belt. This
is, of course, due to the diluting effect of the low tritium water vapor
from the surface ocean water. The results of this factor is to create
nonuniformities in the average tritium fallout concentrations for individual sites within a given latitude belt. Annual tritium deposition
values for different sites within a given latitude belt are more uniform