CLOUD-MOTION was established in Sep. 2017. 15 ESRs were appointed and research plans were set up.
As the core of the research activities three experiments were conducted at the CLOUD chamber to investigate aerosol nucleation processes. Comprehensive measurements of the precursor chemistry as well as the nucleation and initial growth rates were conducted for a number of chemical systems, comprising several hundred experimental runs. The focus of investigations was on the following systems:
• tropical free troposphere: isoprene and α-pinene in combination with sulphur compounds for a range of temperatures down to -50°C (e.g. Caudillo et al., ACP, 2021).
• marine system: iodine and sulphur compounds that are representative for the atmosphere in coastal or open ocean areas (e.g. Shen et al., submitted, 2022; He et al., Science, 2021).
• urban nucleation: aromatic compounds such as toluene and cresol as well as the inorganic acid-base system of sulphuric and nitric acid with ammonia and dimethylamine (e.g. Wang et al., Nature, 2020; Martens et al., submitted, 2022).
Activation properties of secondary aerosol for cloud droplets and ice particles were also investigated. Aerosol particles were nucleated and grown in the CLOUD chamber from vapours under various conditions (chemical species, relative humidity, temperature, and ion concentrations). A wide range of secondary aerosols were investigated (inorganic, pure biogenic, multicomponent, marine, and urban). The cloud activation properties were investigated for liquid droplets (cloud condensation nuclei, CCN) and ice formation (ice nucleating particles, INP). Significant process understanding was achieved from these experiments (e.g. Bertozzi et al., 2021).
Transfer of results into global and cloud-scale models was also performed (e.g. Ranajithkumar et al., ACP, 2021; Wang et al, submitted manuscript, 2022). With these modelling studies the results of CLOUD-MOTION are directly applied to improve our understanding of important aerosol processes in the atmosphere and their influence on the radiation budget and climate.
As an exploitable result, an innovative gas chromatographic (GC) coupling design for a TOF mass spectrometer was developed, characterized and tested by the ESR at Tofwerk AG. The patenting process for this device is ongoing.
A new CCN generator was developed to produce highly charged CCN of either polarity. Expansion experiments were performed with highly-charged CCN and compared with similar experiments using uncharged CCN.
Twelve collaboration meetings and data workshops took place, three CLOUD-MOTION Summer Schools and one Winter School were held (some as online meetings due to the corona pandemic).
All ESRs received comprehensive training on the preparation, operation, troubleshooting, and data analysis procedures for their individual instruments or models. They all learned also to operate the complex CLOUD chamber for conducting the shifts during the experiments.
Progress of the ESRs was regularly reviewed. Overall, excellent progress has been achieved by the ESRs. All ESRs are co-authors of various peer-reviewed publications of the CLOUD collaboration, including publications in high impact scientific journals. Many ESRs have published first-author papers already. The process of publishing the results in scientific journals is still ongoing. The list of publications and conference presentations was submitted as Deliverable 5.2 and it can be viewed at
https://www.cloud-motion.eu/publications(öffnet in neuem Fenster).
All Milestones were reached and all Deliverables were provided to the Participants Portal in time.
