Table 1—SOURCES OF RADIOACTIVE FALLOUT TO DECEMBER 1957* Country Latitude Mt Tropospheric debris U.S.S.R. 50°N 1.7 U. S. (Nevada) U.S. (Pacific) 37°N 11°N 1.0 1.3 U. K. (Pacific) U.K. (Australia) 3°N 35°S 1.5 0.1 Stratospheric debris U.S. 24.8 U.S.S.R. 11.2 * Data from W. F. Libby. ia | 10° 0° sr%° MC/SQ MILE q 0 90° 7o* 6o® 50° RELATIVE UNITS 1.0 2 a = 05 = — 40? 80? 20° NORTH LATITUDE / \ KNOTHOLE obt e+—tT 90° 70" 60" 50° (a) aan / I’ sespor- \ “ 10° _— NS re \ / castre \ \ ~~ | ee — — ~~ po 10° ee j 50* +60" 70° 90° _ \ “ao™ ee 40° 30° 20° NORTH LATITUDE 20° 30° 40, SOUTH LATITUDE oF (b) — — ~ ~~ 7 eaten 10° 20° 30° «40 SOUTH LATITUDE 50° 60° 70° 90° Fig. 2——a. Total tropospheric fallout: --- United States; -—~~, United Kingdom; —+—- ~, USSR. b. Observed tropospheric profiles from U. 8. tests. 1953 in Nevada centered around 37°N. Essentially, all the fallout that is deposited is tropospheric because the tests in Nevada are rarely powerful enough to throw debris into the stratosphere. The lower part of the same figure shows a pattern around 11°N. This is the fallout that has occurred within the first 30 or so days after the Castle test series at the Pacific 329