50
O
i
~
Samples from 30,000 to 35,000 feet
Trend in the tropical stratosphere
x
40
_
Samples from 60,000 to 70,000 feet
Samples from 40,000 to 55,000 feet
®
_.
—
O
7’”.l™
/
®
oO
e
o.|0|UO
~.
SA
~
~
O
oN O
@
~
o~.
n
@O7
WO
O
e
@
-
—
xXx
SO
~
mn
dpm Ce 1a4 /dpm Sr
5
SL
@
90
20 —
fos,
e
~
O
~
e
x
oO
a~_ 8
bd
T
O
-
~
7
°°.
*e.8
Oo
~Q.
@
oe)
~
—
~
~
T
O
al
5 e
—_
~
4
4
P
miailmiujujalsjo[n{o vf [mjalm] vy vJA}S]O]N [0 vfFim{ajm{u
I958
1960
4
9
Fig. 3 -- Variation with time of the monthly average for Ce! 4 sr 0
in samples collected in the northern polar stratosphere
(30°N-90°N)
a9