Influence of inversions upon precipitation deposition of radioactive aerosols

Abstract

The role of the tropopause as a thermal barrier to aerosol transport and direct stratospheric tapping by precipitation processes has been studied extensively. Several different transport mechanisms across this inversion, including some involving precipitation-scavenging processes, have been postulated. Gradients of radioactive aerosols are also expected across low-level inversions within the troposphere. These are generally more accessible for experimental study. Several of our studies on the meteorological influences on radioactive aerosol deposition by precipitation have involved the presence of inversions, both at the tropopause and at low levels. The inversion aspects of three prior studies are reviewed. The first involves the penetration of the tropopause by convective storms. Radiochemical and radar-meteorological analyses of two severe storms in Oklahoma in May 1963, both of which penetrated to heights above the tropopause, are compared to data for three contemporary convective storms in central Pennsylvania none of which penetrated the tropopause. The second concerns the changes in radioactivity concentration in precipitation associated with the overturning of the marine layer during a Pacific extratropical cyclone sampled at Santa Barbara, California, on February 7, 1962. The third involves an examination of the vertical distribution and transport by air motion and precipitation across the trade wind inversion at Hawaii during periods in 1963 and 1964.DOI: 10.1111/j.2153-3490.1966.tb00264.x