NUCLEAR-WEAPON AND CHERNOBYL DEBRIS IN THE TROPOSPHERE AND LOWER STRATOSPHERE

High altitude aircraft sampling of aerosols has been carried out at 4-7 levels up to 15 km over Poland. From 1973 to 1991 a total of 102 vertical concentration profiles of Sr-90, Cs-134 and Cs-137, and 83 profiles of 144 Ce were determined. One year after the sub-megaton nuclear test in 1980, Cs-137 was almost completely removed from the stratosphere. The Chernobyl debris was found in the stratosphere from the third day after the accident until the end of 1991. In May 1986 the concentration of Cs-134 and Cs-137 at stratospheric altitudes reached about 0.5% of that between the ground level and 3 km. Residence times of Chernobyl radiocesium in the lower stratosphere systematically increased between 1987 and 1991, in variance with those of the debris from nuclear tests. The vertical concentration profiles and the long residence times of radiocesium indicate that the non-violent meteorological processes were transporting the Chernobyl debris into the lower stratosphere, immediately and long after the accident. We postulate that the same quiescent processes transport vast amounts of resuspended particulate organics from the surface of land and sea into high altitudes, and may thus bear on the chemistry of the stratosphere.