Mesoscale processes in troposphere-stratosphere interaction

This project of the Leibniz Institute of Atmospheric Physics (IAP) aims to assess the role of mesoscale motions in the dynamical interaction of the troposphere and stratosphere, particularly during northern winter. This will be done by means of mechanistic GCM experiments performed at very high spatial resolution in combination with sophisticated turbulence measurements in the upper troposphere/lower stratosphere (UTLS) using in situ and radar techniques. Corresponding methodologies have already been developed and measurements will be performed at IAP in Kühlungsborn (54N) and at the ALOMAR laboratory in northern Norway (69N). A main task is to explore the link between gravity waves (GWs) and Rossby waves (RWs) in order to improve our understanding of the causation of planetary RWs, which basically control the internal variability of the troposphere-stratosphere system. Furthermore, we plan to assess the turbulent dissipation of kinetic energy in the upper troposphere and lower stratosphere. This quantity serves as a measure for the GW activity and provides a benchmark of the mesoscale energy cascade. By means of climate change experiments we shall estimate the changes in both the generation of planetary RWs and the mesoscale energy cascade due to global warming. Moreover, the vertical and horizontal mixing of minor constituents due to GWs will be assessed along with the mean age of air.