RADIOACTIVITY ALONG THE 80TH MERIDIAN
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WESTWOOD, N. J.
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1962
Fig. 8—Ratios of Sry to 9Sr activity in the air and in precipitation at
various northern-hemisphere sites during 1962. The ®Sr/Sr ratio is
180 at ty (Oct. 15, 1961),
tion of U. S. tests to northern-hemisphere 88Sr levels during this pe-
riod. This increase is equivalent to less than a 1% contribution of the
U. S. tests to the Sr levels. After July the **Sr/"Sr ratio increased
abruptly; the U.S.S.R, 1962 series (August 5 to December 24) was assumed to be the dominant contributor to the ®*Sr levels. Similar con-
clusions can be drawn from **Sr/'4Ce and *y/"*Ce activity ratios.
Latitudinal profiles of the Sr activity concentrations in the air
along the 80th meridian (west) are plotted in Figs. 9 to 11 for the bi-