[en] Stratospheric inventories of Sr-90 over the period 1963--75 yield T₁2asterisk/ = 6--7 months for the inventory difference between Northern and Southern Hemispheres, T₁2N/ = 9--10 months for the decay of the Northern Hemispheric inventory by transfer to the troposphere and Southern Hemisphere, T₁2T/ = 10--11 months for the decay of the total stratospheric inventory, and T₁2E/ = 2.5--3.5 years for the decay of the Northern Hemispheric inventory by transfer to the Southern Hemisphere alone