. “y -3a- ¢ words the vertical mixing in tHe stxratosphere nad occurred rapidly. This is one of the seriouc assumptions which aii tue modeis have in commoi.. There appeazs to be a considerabie speed Wicthsywhich the stratosphere mixes, particuiariy model one assumes essentially inctantaneous mixing though, of course, as shown in the above remazik one need not do this and perhaps three montne time would be a reasonable figure to use. There wa. another tracer added in the Johnson Inland snots by virtue of the fact these were tie fivet hydrosen bomcu ever fired in the stratosphere. ‘*s has been cemaziked previourly, ail of the hydrogen bomos release a conciderable amount of tritium io7 , but because the devices previously have always been fired in the troposphere where a lav,e quantity of watez is iz:corpocated in che firepali with the result that wher it rises into the utratosphere and coois maxing the familiar white cloud which consists of rather iarge ice crystals whicn catcher quickiy and thus carry che tritium back to earti azain. This did not happen for the two uevices fired over Johnson Iclarid in the stratosphere, and therefore, we can expect that for tne et first time the ctratosphere has its tritium content of its water vaised appreciabiy above the cevei it nad previouciy uue to the cosmic rays. The stratosphere is so Low in moisture (a faixz extimate seemc to pe avout lo millisrams per square centimeter of the earth's. surface for the entire stratosphere as compared to somethin; Like 4 to 3 gram. perc square centimeter for the

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