The appearance of mesospheric coolings during sudden stratospheric warmings is an example for the influence of gravity waves. In a study of satellite data and numerical simulations it was found that this effect depends on the form of the polar vortex. Here the gravity wave filtering effect of the zonal and vertical structure of planetary waves (wave1/wave2 and straight/tilted) is investigated. The analysis of a process model shows that the tilt of the stratospheric planetary waves decreases the zonal-mean mesospheric gravity wave drag as suspected.

---

*Email: zuelicke@iap-kborn.de
*Preference: Poster