The contributions of the theory and modelling department to the institutes objectives are as follows:
Coupling between atmospheric layers
The investigation of the coupling between atmospheric layers with focus on the middle atmosphere requires a consideration stretching from the surface respectively the troposphere up to the lower thermosphere. The most important dynamical processes are wave motions with scales from planetary extensions (about 10 thousand kilometers) to the mesoscale (few 10 kilometers). The interaction of the waves with the mean flow and amongst each other is closely connected with the generation of turbulence and a large-scale circulation. The latter extends over the considered height range and comprises both hemispheres in the uppermost layers. The associated tracer transport has consequences for the radiation balance. The following topics are studied:
Exploration of the mesosphere and lower thermosphere
Medium-term variations on time scales between weeks and months, which are interesting for theoreticians and for observers, are studied for the mutual interaction of circulation, waves and turbulence in the topic
Long-term changes in the middle atmosphere
Long-term changes can appear because of enforced (external) trends or may be the expression of natural (internal) variability. The detection of changes is complemented with the attribution of processes in the topic
For the study of these research topics a variety of theories and diagnoses are applied on model simulations and observations. In the frame of a model hierarchy, two circulation models and a chemistry transport model are continuously maintained and further developed at the department.