Scientific objectives

Aiming on improving our understanding of the role of the Arctic stratosphere in the atmospheric system and improving future projections of the development of the ozone layer, the key objectives of POLSTRACC are:

• Investigating the structure, dynamics and chemical composition of the UTLS at high latitudes with a special focus on the Lowermost Stratosphere (LMS). Studies on the outflow of the polar vortex and its influence on the composition of the LMS at high and middle latitudes
• Improving the understanding of catalytic processes involved in polar ozone loss with a focus on chlorine and bromine chemistry in the LMS
• Improving the knowledge on polar stratospheric cloud (PSC) composition, de-/nitrification by sedimentation of nitric acid-containing particles and the role of gravity waves or orographic waves on PSC occurrence
• Investigating Arctic cirrus clouds, their influence on the radiative forcing and their potential for denitrification, dehydration and chlorine activation

The POLSTRACC mission will employ a payload of remote-sensing and in-situ instruments covering a variety of trace species and physical parameters of the atmosphere, with contributions from institutes of the Helmholtz Association, the National Aeronautics and Space Research Centre (DLR), universities and partners. The measurements will be complemented by atmospheric model studies on regional to global scale, allowing to test improved parameterisations of processes involved in chemical ozone loss, atmospheric dynamics and the radiation budget of the UTLS.