An indicator of gravity waves: lenticular polar stratospheric clouds during SouthTRAC (Photo: Marko Magister, BigAir Factory)
The SouthTRAC measurement campaign with the German research aircraft HALO was successfully performed in the region of South America and the Antarctic Peninsula end of 2019. This region is a hotspot of middle atmospheric gravity waves. An overview and first results of the data analysis were presented to the international community by members of our matrix group "Middle atmosphere" on the EGU General Assembly 2020, which was held as an online event from 4.-8. May 2020, offering access to the whole scientific community. One highlight of SouthTRAC are the observations of the ALIMA (Airborne LIdar for Middle Atmospheric research) instrument that has been developed at the DLR Institute of Atmospheric Physics in the past couple of years, showing the propagation of gravity waves into the stratospheric polar night jet. This is the first experimental proof that these waves are refracted towards the polar vortex, hundreds of kilometres away from their origin at the mountains of the southern Andes and the Antarctic Peninsula. The SouthTRAC observations provide a way forward to improve atmospheric models. A news article about these observations and the role of gravity waves in Earth system modelling was published online shortly after the EGU General Assembly in Science.