Stratospheric-Tropospheric Exchange Based on Radioactivity, Ozone and Potential Vorticity

Abstract

Abstract Vertical cross sections of potential vorticity, computed and contoured by band, and hemispheric distributions of potential vorticity, computed and contoured by machine, are compared to both discrete and continuous measurements of radioactivity made during Project Springfield. Comparisons made in the upper troposphere and lower stratosphere show a positive correlation between potential vorticity and radioactivity of stratospheric origin. The radioactivity measurements and machine-computed isentropic trajectories prove that stratospheric air from high latitudes is transported southward and downward into the troposphere as the tropopause folds. Changes in potential vorticity and the concentration of radioactivity along the trajectories also prove that subsynoptic-scale mixing destroys the extruded stratospheric layer in the troposphere. The mass outflow from stratosphere to troposphere associated with tropopause folding is compensated by a quasi-steady inflow along the tropopause. This inflow is nec...