Geophys. Res. Lett. (2007), 34, L02809, doi:10.1029/2006GL028369.
The sharpness of the extratropical tropopause is investigated using baroclinic life cycle experiments. In these simulations, slow synoptic scale dynamics leads to a net tropopause sharpening. The mechanism involves vertical convergence of the ageostrophic wind. The results support earlier suggestions from idealized theoretical studies.