GLOBAL DISTRIBUTION OF TRITIUM
671
The ratio for 1961 before October, which should reflect a purely
stratospheric input. was 316. This reflects the lower fusion to fission
ratio for the 1958 tests as compared tothe 1961 and 1962 tests.
In Table 7 the ratio of the deposition rate for tritium to the depo-
sition rate for "Sr is given for 1963 at several sites in the northern
and southern hemispheres. A single site did not always provide both
the tritium and Sr fallout data. In this situation the two nearest
neighboring sites were taken to give the data on both nuclides. In the
north the ratio increases toward the high latitudes, and in the south the
ratio is substantially lower and remarkably uniform. These distribution
patterns indicate significant differences between the atmospheric transport mechanisms in the two hemispheres. The significance is being
investigated.
Table 7—RATIO OF RATE OF DEPOSITION FOR
TRITIUM AND "Sr IN 1963, MC/KM?
PER CENTIMETER OF PRECIPITATION
Site
Tritium
30Sr
Latitude
Ratio
Keflavik
64°N
336
Stuttgart
(four months)
Vienna
Chicago
Frankfurt
Vienna
Argonne
48°N
48°N
42°N
475
420
365
Teheran
Waco
Hong Kong
Hilo
Entebbe
Teheran
Dallas
Hong Kong
Hilo
Nairobi
35°N
31°N
22°N
19°N
O°N
214
231
199
75
65
Brisbane
Perth
Kaitoke
Brisbane
Perth
Wellington
27°S
32°S
41°5
60
63
53
Punta Arenas
51°S
61
Reykjavik
Goose Bay
Goose Bay
Port Stanley
(Falkland Islands)
61°N
654
The mean ratio for the five sites in the southern hemisphere is
60, and the individual departures from this ratio are small. This suggests the interesting possibility of calculating tritium-fallout concentrations for the many sites inthe southern hemisphere for which tritium
measurements are not available. The equation is
19x10?
T.U, = ——_-—
n
(VD,
D
D
a
aT
P,
G76