15 ae | 30 | 10 -— 20 a —_ | STRATOSPHERIC | SAMPLING PERIOD MEAN: 20 MT OR 5 -— Lag 2 = 40 MC/SQ MILE {0 | 5 o2 3 > 2 = 3 n Ee t oO 2f- uJ = u wn {FE O5 2 ee } 0.3 1952 | 1953 1954 : 1955 1957 0.6 Fig. 7 — Stratospheric inventory. 80 7 70 }— * 60; 3 + — y4 — a ++ _ 50 eo uw 8 _ 2 + Oo 40 F— ~~ + = + + +? Py 30 F— o + + ; + | 2 60 + ++ + + ; — + + _ ++ — + + ++ + + +F 40 E30 + +++ Boo n 0 * + + +tety 30 — t . LL 0 NORTH 60 SOUTH Fig. 8 — Stratospheric Sr® content, Winter, 1956-1957. ~---, calculated average value assuming 20 Mt, tropopause at 45,000 ft, and a filter efficiency of 25 per cent. 335 ~ 30 aoe ba ete rer etehae