Stratospheric ozone descent into the troposphere: Case studies

Summary The penetration of stratospheric air into the troposphere, revealed by high ozone concentrations measured both by an aircraft (Electra) and at a mountain station (Mt. Cimone) during a lee cyclogenesis event (April 24–25, 1982), is investigated. A detailed analysis of the meteorological fields and the application of the isentropic-trajectory method allowed us to reveal the dynamical processes responsible for the ozone transport into the troposphere. We show that the two episodes of high ozone concentrations have to be attributed to the evolution of two distinct upper vortexes, only one of which was associated with surface lee cyclone development. Paper presented at the 1° Congresso del Gruppo Nazionale per la Fisica dell'Atmosfera e dell'Oceano, June 19–22, 1984, Rome.