Tafferner, Arnold (Institut fur Physik der Atmosphare, DLR Oberpfaffenhofen)
The generation and decay of a cut-off-low over the Mediterranean is simulated with a high resolution mesoscale model. The diabatic and turbulent processes causing a change of potential vorticity in the upper troposphere are identified and their effect on the tropopause is quantified. In a simulation experiment without the effect of latent hheat release and atmospheric radiation the cut-off-low develops more strongly and decays only slowly. The tropopause defined as surface with constant potential vorticity of 2 PVU is found to be eroded from bellow within the cut-off-low during the decaying phase. The height change of the tropopause within the cut-off-low allows a rougth estimation of the mass exchanged between stratosphere and troposphere.