Spatial-temporal changes in the fallout intensities and in the concentrations of tracer indium in precipitation during field experiments in 1983

The results of two field experiments, carried out on the 7th and 9th of August, 1983 at the proving ground in the Moldavian SSR, are presented. The aim of these experiments was to study the transport of the artificially injected tracer indium in Cumulonimbus clouds. The background concentrations of indium in precipitation were measured (from 0.5x10-9 to 2.10-9 g·1-1). After the injection of 0.5 kg of indium into the cloud the concentrations fluctuated from 0.5x10-9 to 4.9x10-7 g·-1. On injecting the tracer between two convective cells (one in the developed phase, the other in the decay one), no transport of the tracer to the cells was noted. In the cloud system which consisted of nimbostratus clouds, the transport of indium was observed in the direction of the cloud system movement as well as in directions opposite and perpendicular to it. 6 refs.; 6 figs