A substantial amount of this research is carried out as part of comprehensive international field campaigns. The field-work is complemented by laboratory studies and theoretical modeling - involving studies of the occurrence of aerosol particles and gaseous constituents of importance for cloud formation, biogeochemical cycles and climate. In order to understand interactions between gases, aerosol particles, clouds and the underlying surface we measure - both by remote sensing and in-situ measurements - the chemical and biological composition of air, cloud water, precipitation and ocean surface water. We also develop numerical models of different complexity to examine how different chemical constituents interact with atmospheric mixing and transport. The models are used to interpret both the in-situ and remote sensing collected data and to study the impact of long-term past and future changes in atmospheric composition. 

 

 
Tropospheric Chemistry
figure by C. Leck
 

Atmospheric aerosol particles and clouds play a central role in the research activities and examples of ongoing scientific projects are the ABC-project and CARDEX aiming at a better understanding of the atmospheric life cycle of soot and its climate effects over the Indian sub-continent and the surrounding oceans. ASCOS and CRACE, are two efforts that are focused on high-latitude atmospheric sources of aerosol particles and their role in cloud formation and Arctic climate change. The project AVIAC attempts to study the interaction between aerosol particles and clouds over the Amazon. AfcCC is aimed at studying the interaction between aerosol particles and convective clouds. The department is also a partner in developing the description of aerosol particles and their influence on clouds and climate in different global climate models, including CAM-Oslo and EC-Earth, We also perform molecular dynamic simulations in collaboration with partners at the Swedish Royal Institute of Technology and host a newly developed large-eddy simulation model for detailed studies of aerosol-cloud interaction.