Project B02:
Transport of aerosols and precursors from the planetary boundary layer into the UTLS – BrIdging Surface emissions, Transport and UTLS Matter (BISTUM)

Brief Summary

By scattering and absorption of incoming solar and outgoing terrestrial radiation, aerosol in the Upper Troposphere/Lower Stratosphere (UTLS) has a direct effect on the Earth’s energy balance. In absence of any major explosive volcanic eruption since Pinatubo (1991), the UTLS aerosol number concentrations remained almost constant at least over the last 29 years. This suggests that UTLS aerosol, in particular the Junge layer, is maintained by mechanisms which balance an ambling but continuous sedimentation loss of particulate material, most likely due to entry of aerosol and precursors. However, the processing of aerosol and precursor material (formation, loss and cloud interaction) during transport, e.g. from the boundary layer into the UTLS, is not yet conclusively understood. It is also unknown whether and how the emission intensity and/or composition of different aerosol and precursor substances can affect this trace matter processing. The extent to which ground-level aerosol and precursor emissions at different emission strengths and compositions influence the properties of UTLS aerosols is also yet to be clarified.
The main goal of this project is to investigate the coupling between surface emissions of atmospheric trace matter (aerosols and aerosol precursors) and the trace matter in the UTLS. This implies that surface emissions reach UTLS altitudes, which requires an effective vertical transport mechanism. In order to investigate this, detailed ground-based trace matter measurements are combined with drone and balloon-borne measurements of aerosols in close proximity to locations where vertical uplift occurs. During field experiments, the coupling will be completed by detailed airborne measurements in the UTLS as well as modelling studies performed within other subprojects of this CRC. The following questions are in focus: Which processes dominate the coupling of surface emissions and UTLS trace matter composition? How effective are these processes and associated particle formation, transformation and loss mechanisms for different aerosol and precursor components? How do surface emissions influence the UTLS aerosol?

Members

Publications

Ebert, M., R. Weigel, S. Weinbruch, L. Schneider, K. Kandler, S. Lauterbach, F. Köllner, F. Plöger, G. Günther, B. Vogel, and S. Borrmann (2023): Characterization of refractory aerosol particles collected in the tropical UTLS within the Asian Tropopause Aerosol Layer (ATAL). EGUsphere 2023, Preprint, 1–45. doi: 10.5194/egusphere-2023-2245.

Groß, S., T. Jurkat-Witschas, Q. Li, M. Wirth, B. Urbanek, M. Krämer, R. Weigel, and C. Voigt (2023): Investigating an indirect aviation effect on mid-latitude cirrus clouds – linking lidar-derived optical properties to in situ measurements. Atmospheric Chemistry and Physics 23 (14), 8369–8381. doi: https://doi.org/10.5194/acp-23-8369-2023.