WP 4. Biosphere-atmosphere interactions


This WP studies the coupling of the biosphere to physical and chemical processes of the atmosphere. Biogenic volatile organic compounds (VOCs) have a central role in tropospheric chemistry. Many VOCs participate in aerosol growth and formation processes . The products formed in the reactions of VOCs with ozone, or OH and NO3 radicals, may have lower volatility, and thus condense into aerosol particles. VOCs also affect the production and destruction of tropospheric ozone. As they compete for OH with methane, they may have an influence on the atmospheric lifetime and concentration of this powerful greenhouse gas . VOCs may also affect the optical properties of aerosol particles. Even though the anthropogenic VOC emissions generally surpass the biogenic emissions in most of Europe, in Northern Europe the biogenic emissions dominate. Also, on the global scale, the biogenic VOC emissions clearly dominate over the anthropogenic ones.

Different BVOCs participate in different stages of aerosol formation and growth. Sesquiterpene oxidation products may take part in aerosol formation itself , while isoprene and monoterpene oxidation products are mainly connected to aerosol growth . Oxygenated VOCs (OVOC) such as carbonyls can also affect the light absorption properties of sulfate aerosols . In order to understand the role of the terrestrial vegetation on atmospheric aerosol formation, growth and properties, we need to investigate especially the poorly known emissions of sesquiterpenes and OVOCs (alcohols and carbonyls), and in particular the regulating factors underlying temporal and spatial variations in emissions from different plant species. In this WP, we will answer the following question:

How will the emissions and properties of biogenic aerosol precursors be altered in the changing climate?