Characterization and optimization of a DUAL channel PERCA for the investigation of the chemistry of peroxy radicals in the upper troposphere

The research of peroxy radical chemistry is an important topic that provides essential knowledge about photo oxidant formation and night time chemistry. Peroxy radicals play an important role in the formation and depletion reactions of ozone in the troposphere. They also play a key role in the cleaning processes of the atmospheric pollution. At the Institute of Environmental Physics (IUP) of the University of Bremen, laboratory studies are performed to characterize and design a dual channel reactor system (DUALER: DUal channel Airborne peroxy radical chemicaL amplifiER) for the measurements of peroxy radicals on an airborne platform in the upper troposphere. The IUP DUALER system, based on the PERCA (Peroxy Radical Chemical Amplification) technique was deployed on the DLR-Falcon 20 of German Aerospace Centre (DLR) during the measurement campaign AMMA SOP2 (African Monsoon Multidisciplinary Analysis, Special Observation Period 2). The West African Monsoon (WAM) is associated with deep convective transport of air masses to the upper troposphere impacted by anthropogenic and natural emissions. The analysis of the measurement results of the DUALER has the aim of understanding the identification of different air masses with different photochemical activity and developing knowledge of source and sink processes of peroxy radicals, as well as the formation and destruction mechanisms of ozone in the upper levels of the troposphere during the WAM. At the experimental part of this work, the implementation of a pressure chamber for improving the characterization procedure of the IUP DUALER for different pressure levels is presented and the results are compared with the performance of the instrumentation during AMMA.