Research topics of the Aerosol and Cloud Chemistry group
Aerosol and cloud particles play an important role in the Earth's atmosphere. They can absorb or scatter incoming solar radiation, thereby influencing the energy balance of the atmosphere. The contribution of aerosol and clouds to the radiative forcing is still one of the largest uncertainties in today's understanding of the climate system (see latest IPCC Report). Aerosol particles and cloud droplets exist in a close relationship: Without aerosol particles, no cloud droplets would form in the troposphere. When the relative humidity increases towards 100%, aerosol particles can act under certain circumstances as a cloud condensation nucleus (CCN) or, at lower temperatures, as an ice nucleating particle (INP). The ability of an aerosol particle to act as a CCN or as an INP is dependent on its size and on its chemical composition, possibly also on its shape and surface properties, however, these processes are still not fully understood. The "Aerosol and Cloud Chemistry" group is therefore active in investigating the connections between aerosol particles and cloud formation. The most important measurement technique is aerosol mass spectrometry, but also different other instrumentation (as scanning mobility particle sizers, optical particle counters, condensation particle counters, multi-angle absorption photometer) are employed. The research group focuses on field experiments (aircraft based but also ground-based, e.g., on mountain stations) that are comlemented by laboratory measurements.