Final Report Summary - ATMNUCLE (Atmospheric nucleation: from molecular to global scale)
The main scientific objectives of the ATMNUCLE were 1) to quantify the mechanisms responsible for atmospheric new particle formation and 2) to find out how important this process is for the behaviour of the global aerosol system and, ultimately, for the whole climate system. The work was divided into five inter-linked work packages (WP) that support each other.
1. Atmospheric clusters; instrument development, quantum chemistry models, laboratory experiments
2. Formation and growth of atmospheric aerosol particles; atmospheric observations, aerosol dynamic modelling, aerosol chemistry, atmospheric chemistry of precursors
3. Aerosol-cloud interactions; atmospheric observations (CCN-counters), cloud microphysics, prediction of CCN concentrations
4. Biosphere-atmosphere interactions; BVOC emissions, processes behind BVOC formation
5. Synthesis; global aerosol load: past, present and future, global modelling
The key steps of this process occur in the sub-2 nm size range, in which direct size-segregated observations have not been possible until very recently. Using detailed observations of atmospheric nanoparticles and clusters down to 1 nm mobility diameter we identified three separate size regimes below 2 nm diameter that build up a physically, chemically and dynamically consistent framework on atmospheric nucleation, more specifically aerosol formation via neutral pathways. Our findings emphasize the important role of organic compounds in atmospheric aerosol formation, subsequent aerosol growth, radiative forcing and associated feedbacks between biogenic emissions, clouds and climate. Actually according to our estimation over 80% of global aerosol load is due to atmospheric new particle formation.
ATMNUCLE has enhanced significantly our understanding of large-scale impacts by atmospheric nucleation. Based both on existing field measurements and large-scale model simulations, we know now that atmospheric nucleation is the dominant source of the particle number concentration and important contributor to cloud condensation nuclei (CCN) concentrations in the global atmosphere. Our co-operative efforts have made it possible to establish, for the first time, an observation-based link between continental biogenic emissions and subsequent secondary aerosol and CCN production confirming the existence of the negative feedback mechanism associated with the continental biosphere in a warming climate suggested by Kulmala et al. (2004, ACP). Model studies demonstrate that biogenic secondary organic aerosol contribute significantly to the magnitude and uncertainties of the present-day indirect radiative effects by atmospheric aerosols. In future, the climatic impacts by biogenic aerosols depend not only on the response of continental biogenic emissions to the changing climate, but also on the complex interactions between natural and anthropogenic emissions in the global atmosphere.
1. Atmospheric clusters; instrument development, quantum chemistry models, laboratory experiments
2. Formation and growth of atmospheric aerosol particles; atmospheric observations, aerosol dynamic modelling, aerosol chemistry, atmospheric chemistry of precursors
3. Aerosol-cloud interactions; atmospheric observations (CCN-counters), cloud microphysics, prediction of CCN concentrations
4. Biosphere-atmosphere interactions; BVOC emissions, processes behind BVOC formation
5. Synthesis; global aerosol load: past, present and future, global modelling
The key steps of this process occur in the sub-2 nm size range, in which direct size-segregated observations have not been possible until very recently. Using detailed observations of atmospheric nanoparticles and clusters down to 1 nm mobility diameter we identified three separate size regimes below 2 nm diameter that build up a physically, chemically and dynamically consistent framework on atmospheric nucleation, more specifically aerosol formation via neutral pathways. Our findings emphasize the important role of organic compounds in atmospheric aerosol formation, subsequent aerosol growth, radiative forcing and associated feedbacks between biogenic emissions, clouds and climate. Actually according to our estimation over 80% of global aerosol load is due to atmospheric new particle formation.
ATMNUCLE has enhanced significantly our understanding of large-scale impacts by atmospheric nucleation. Based both on existing field measurements and large-scale model simulations, we know now that atmospheric nucleation is the dominant source of the particle number concentration and important contributor to cloud condensation nuclei (CCN) concentrations in the global atmosphere. Our co-operative efforts have made it possible to establish, for the first time, an observation-based link between continental biogenic emissions and subsequent secondary aerosol and CCN production confirming the existence of the negative feedback mechanism associated with the continental biosphere in a warming climate suggested by Kulmala et al. (2004, ACP). Model studies demonstrate that biogenic secondary organic aerosol contribute significantly to the magnitude and uncertainties of the present-day indirect radiative effects by atmospheric aerosols. In future, the climatic impacts by biogenic aerosols depend not only on the response of continental biogenic emissions to the changing climate, but also on the complex interactions between natural and anthropogenic emissions in the global atmosphere.