Tropical cyclone Marlene and stratosphere-troposphere exchange

Convective tropical cyclones initiate exchanges of mass and energy between the troposphere and the stratosphere. Recent analyses of ozone and water vapor measurements from Measurements of Ozone by Airbus In-Service Aircraft (MOZAIC) data [Suhre et al., 1997] suggest that stratospheric ozone inputs to the troposphere can occur in the tropics near zones of deep convection. In the present paper, we analyze a case study of spectacular stratosphere-troposphere exchange directly linked to the strong tropical cyclone Marlene, that occurred near Mauritius and Reunion Island on April 1995. The amplitude of the ozone peak (300 ppbv at 300 hPa) is comparable to those observed by Suhre et al. In this case, ageostrophic phenomena dominate advective phenomena. Therefore convective effects can be at the origin of mesoscale tropospheric ozone contaminations which affect the entire tropical free troposphere.