Fig. 3.

Global stratospheric ²³⁶U fall-out in kg/month. Northern (solid) and southern (dashed) hemispheric fall-out from testing of thermonuclear devices are shown separately. This is a new version of the model presented in the UNSCEAR (2000) report, adapted to gauge ²³⁶U production from these tests. The initial output of the model is actually in terms kt TNT equivalent fission yield, which has been converted to kg of ²³⁶U using our conversion factor (7.4 kg per Mt TNT equivalent) derived from the ²³⁶U/²³⁸U ratios in the coral core record. The fall-out model indicates that by the end of 1964 more than 80% of all bomb-produced ²³⁶U had already been deposited on the earth's surface.