Approach

A central role in the CAINA project will be played by the Ruisdael Observatory, equipped with extensive observational tools for pollutants, wind fields, and clouds. This creates an ideal outdoor laboratory to study pollutant-cloud interactions under varying nitrogen regimes. We will combine long-term observations and intensive field experiments to study processes that govern CCN concentrations, effects of nitrogen pollutants on cloud microphysics, and cloud processing of aerosols. 

The field measurements will be interpreted with the help of controlled cloud chamber experiments in the dynamic AIDA cloud chamber, and with the use of high-resolution, cloud-resolving modelling. The observational strategies will optimally constrain a unique Large Eddy Simulation (LES) model that can simulate both non-equilibrium chemistry of nitrogen pollutants and cloud-aerosol interactions. The constrained LES model will quantify both the relevance of cloud processes for nitrogen-containing pollutant levels as well as the pollutant effects on cloud properties. This knowledge is of vital importance to better predict the impact of the anticipated global shift to nitrogen-dominated pollution regimes.