Orographic gravity waves in OH-airglow imaging systems

Atmospheric dynamics is strongly influenced by waves on different scales. Airflow over mountains can lead to all kinds of atmospheric waves, planetary and gravity waves as well as infrasound. Under certain circumstances these waves can propagate through the atmosphere and lead to a re- distribution of energy. In the case of gravity waves, a stably stratified atmosphere is a mandatory requirement for their generation and vertical propagation. Additionally, the vertical propagation depends on the horizontal wind field. In the Alpine and pre-Alpine region, we currently operate five OH-airglow imaging systems, which allow the investigation of orographic gravity waves. Depending on tropo-, strato- and mesospheric wind and temperature, it is checked which wavelengths can propagate into the fields of view of our instruments. This is done for a whole year in order to take into account annual and semi- annual cycles in wind and temperature. Concerning the generation of gravity waves, we put our focus on our OH-airglow imager (FAIM) deployed at Otlica (45.9°N, 13.9°E), Slovenia. Here, we also have additional measurements of an OH-airglow spectrometer (GRIPS). In case studies, we investigate whether strong wind events (Bora) lead to strong gravity waves activity or enhanced potential energy density