Environmental & Climate Sciences Department Seminar

Aerosols and their climate forcing represent one of the largest uncertainties in global climate models (GCMs) today. Despite being tiny in size (~1nm - ~10 µm in diameter), ambient aerosols have large impacts through their microphysical interactions and climate feedbacks. For these reasons, direct in situ measurement of aerosol chemical, physical and morphological properties is a high priority to reduce these uncertainties. Absorbing aerosols that absorb light and contribute to atmospheric warming are of particular interest due to their anthropogenic sources, potential to increase in the future due to climate change, and impacts on human health. Large uncertainties exist on the extent of the warming that absorbing aerosols cause, specifically due to morphology and mixing state as black carbon physical and optical properties change as particles are transported in the atmosphere due to oxidation, coagulation, and condensation. For this reason, black carbon and organic carbon aerosol species that are emitted from combustion sources such as biomass burning and diesel sources will be presented. Emission ratios, physical and optical properties will be compared to those from controlled laboratory studies to understand carbonaceous aerosols and their transformations in the atmosphere. Laboratory measurements are used as a framework to understand the ambient observations and to improve model treatment of aerosols and aging in global climate models.