09 T T T 500 Lo T T T T T Tt T STRONTIUM-90 CONCENTRATIONS ~ 30° N-90°N 70000 Fr. QQ 0 ; 200 = O Sr 100 L N-D | |[U-F Ley yg J-A 1958 (957 Fig, 0 S-O 0 Oo S ® 6 - A e M-A M-J e ® A A A ; 4 e o e A a A e O O ® Oo é e « e A Oo Oo @ 90 (dpm/tOOO SCF) 300 G6O0000F| O O 400 Lo 65,000 Fr. e | N-D| | J-F l M-A M-J l J-A S-O Nl | N-D|J-F 1959 4 -- Strontium-90 concentrations (in dpm /1000 scf) at 60, 000, 65,000, and 70,000 feet versus time for latitude band 90°N-30°N, M-A \ i960 MJ