Seasonal and latitudinal variations of atmospheric radioactivity along Australia’s east coast (150°E longitude)

Preliminary results obtained from a network of air sampling stations located between 9° S and 43° S along about 150° E longitude indicate that the “spring” maximum the atropospheric radioactivity concentrations propagates poleward at a rate of about 35 cm s-1. The peak appears to be associated with an injection of air enriched with Be-7, presumably stratospheric, at about 20°S during September-October. A secondary injection of air containing high concentrations of Be-7 is suggested by the results, occurring southward of 35° S during November-December.

Use of artificial radionuclide concentrations as southern hemispheric tracers is severely hampered by continuing weapons testing in the south Pacific region. A complete comparison between the various models of the atmospheric general circulation and the results from studies such as the present awaits the collection of data unaffected by weapons testing programs.