Analysis of gravity waves during the POLINAT experiment and some consequences for stratosphere-troposphere exchange

Measurements of horizontal wind speed and direction obtained during the Pol lution from Aircraft Emissions in the North Atlantic Flight Corridor experi ment are used to identify some waves propagating near the tropopause level. The variation observed simultaneously in the ozone and water vapor distrib ution allows the signature and different characteristics of the waves to be identified. With the help of the analysis of European Centre for Medium-Ra nge Weather Forecasts the conditions for generation of different kinds of w aves are reviewed. It is shown that some of the characteristics of the obse rved waves are a consequence of nonlinear wave-wave interaction. The irregu larity of the tropopause height in the region suggests that the propagating waves can be a mechanism for cross-tropopause mixing.