Stratospheric Fallout of Strontium-89 and Barium-140

Spring Peak of Strontium-90 Fallout

An increasing trend of Sr(90) concentration in rain observed at Fayetteville, Ark., after November 1959, indicates that the seasonal and global movements of stratospheric air masses, such as described by Brewer (I) and Dobson (2), play an important role in causing the spring peaks of the Sr(90) fallout.

Fallout from nuclear detonations of February and April 1960

A sharp increase in the ratio of strontium-89 to strontium-90 in rain was observed at Fayetteville, Arkansas, after the French nuclear detonations of February and April 1960. Experimental data obtained suggest the possibility that part of the debris from atom bombs detonated in the tropical region may enter the stratosphere.