PEACE

(PEroxy rAdicals measured by OF-Cavity Enhanced spectroscopy in the free troposphere with a focus on the upper troposphere / lower stratosphere)

• Funded by the DFG within the HALO SPP 1294/2 program (2011-2013). Extended to 2015.
• Aircraft: HALO

Scientific objectives

PEACE builds on the investigation and experience gained during the first phase of the HALO SPP 1294/1 in the framework of the project REVOLVER.

PEACE plans to study the oxidative capacity of the free troposphere by making accurate measurement of peroxy radicals onboard the high altitude and long range aircraft HALO during the OMO initially planned for summer 2010. PEACE will focus on the determination of the vertical profiles of RO2* and their precursors, which are in part convected from the boundary layer. Knowledge of the radical budget in the atmospheric layers affected by extratropical convective events provides the information required to assess the potential global impact resulting from the production of additional free tropospheric O3 in these layers. Special interest will be paid to the determination of the radical composition in the upper troposphere and lower stratosphere (UT/LS). This region is very sensitive to the amount of actinic radiation and mixing processes and its characterization is crucial for assessing the climatic effect of stratospheric changes.

Within PEACE, the double reactor and the OF-CEAS NO2 detector prototypes developed within REVOLVER were further optimized, and the final PeRCEAS instrument was certified for its deployment in the OMO mission. Ongoing research is the analysis and interpretation of the measurements performed during the OMO experimental campaigns (OMO-EU and OMO-Asia) and the obtained radical data.