Summary
The zonal anomalies data in total ozone and thermal tropopause height shows that ozone depletion during austral spring has a strong influence on the height and sharpness of the tropopause over West Antarctica. Measured elevation of the tropopause is explained by low stratospheric temperature due to the seasonal temperature minimum in winter and ozone losses in spring. Accordingly, tropopause zonal asymmetry is determined by strong east-west asymmetry of the surface temperatures in the winter and total ozone asymmetry in spring. Lowering of the elevated tropopause over the boundary of the Antarctic continent is explained by the influence of the cold continental troposphere both in winter and spring. We show some details of relative contribution of radiative and dynamical processes to the Antarctic tropopause formation. The sloping meridional profile of the tropopause and widening of the transition layer between the troposphere and stratosphere over West Antarctica suggest the possibility of enhanced air mixing not only vertically but also horizontally. The research was partly supported by Taras Shevchenko National University of Kyiv, project 06BF051-12 and Australian Antarctic Science project 737. The research was undertaken in the framework of the ORACLE-O3 IPY project and the Polar Atmospheric Chemistry at the Tropopause (PACT) SCAR Action Group.