A 2-D stratospheric and mesospheric dynamical model including drag and diffusion due to gravity wave breaking is used to simulate winter mesospheric temperture inversions similar to those observed by Rayleigh lidar. It is shown that adiabatic heating associated to descending velocities in the mesosphere is the main mechanism involved in the formation of such inversions. Sensitivity tests are performed with the model and confirm this assumption. It is also explained why other previous similar studies with 2-D models did not show mesospheric inversion layers. ¿American Geophysical Union 1990