The effect of tropopause height on the content of radioactive debris in surface atmosphere
The effect of tropopause height on the content of Cs-137 and total beta activity in surface atmosphere was considered for the period of intensive nuclear weapon tests, from 1968-1971. The activity of Cs-137 in monthly air filter samples was measured by gamma spectrometry and total beta activity was determined by 2 pi proportional counters. The results were correlated with data on tropopause height. The results indicate that the movement of radioactive debris from the stratosphere into the troposphere occurs simultaneously with the changes in tropopause height. The content of long lived radionuclides in the troposphere follows the changes with a certain delay due to meteorological conditions in surface air and due to the location of sampling. (C) 1997 Elsevier Science Ltd.