The increasing impact of climate change is one of the greatest challenges society faces in the 21st century. Aerosol-cloud interactions still represent the largest uncertainty in current projections of future climate. Ground-based in-situ observations of climate-relevant parameters are the key input for understanding the changing climate as well as for forecasting future trends.
The goal of the proposed AeroCloud AT project is to establish a unique infrastructure with two measurement sites for extensive research on aerosol-cloud-climate interactions.
The combination of the high alpine Global Atmosphere Watch (GAW) site at Sonnblick Observatory (SBO, 3106 m a.s.l.) with the newly renovated urban aerosol observatory at the University of Vienna forms an outstanding cooperative infrastructure for this purpose. AeroCloud AT brings together the complementary expertise of GeoSphere Austria (formally ZAMG), TU Wien, and the University of Vienna, combining the unique location and synergistic capabilities of SBO in the free troposphere and University of Vienna’s Aerosol Observatory within the planetary boundary layer in an urban area (Vienna) using previously unavailable instrumentation. This enables long-term measurements of important aerosol and cloud parameters that cannot be retrieved in existing measurement programs or are only represented as snapshots in short-term measurement campaigns.
AeroCloud AT extends the existing instrumentation for aerosol and cloud particle size distributions in the size range between 10 nm and 50 µm. The online acquisition of the chemical composition of the non-refractory submicrometer aerosol allows the analysis of aerosol sources with high time resolution. For the first time in Austria, long-term online measurements of bioaerosols and microplastics are made possible through a novel combination of optical spectrometry, fluorescence spectroscopy, and holographic imaging. The focus on the coarse particle mode (particles > 1 µm), which is challenging to measure, expands aerosol composition knowledge by measuring novel parameters, and will reduce uncertainty in aerosol-cloud interactions and their impact on the climate. The measurements of ice-nucleating particles suggested in this proposal form the basis for studies of the effects of mineral dust, microplastics, and bioaerosols on cloud properties. In addition, cloud phase (water, mixed-phase, and ice clouds) and cloud particle shape are recorded at the SBO.
This novel data set will give new insights on the influence of specific aerosol particles on cloud formation and thus on the climate. The simultaneous observation of rarely-studied aerosol constituents (such as microplastics in the atmosphere) at two complementary measurement sites provides insight into both the local distribution of these aerosol particles and their transport through the atmosphere. Such insights are essential for understanding the environmental and climatic relevance of aerosol particles. The requested infrastructure significantly expands the measurement portfolio for aerosol and cloud research in Austria and substantially advances research on aerosol-cloud-climate interactions.
The AeroCloud AT infrastructure also provides an excellent platform for international collaborative projects and measurement campaigns with world-class European and non-European interdisciplinary research groups. It is also available to a limited extent for dedicated research questions of non-academic research partners against payment of user fees. The new infrastructure creates synergies with the pan-European research infrastructures ACTRIS (Aerosol, Clouds and Trace gases Research Infrastructure) and eLTER (Integrated European Long-Term Ecosystem, critical zone and socio-ecological Research). AeroCloud AT also supports the Austrian government program 2020-2024 which emphasizes the importance of large international research infrastructures in the field of aerosol and climate research.