AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Global Perspectives on Aerosol Hygroscopicity and Cloud Forming Ability: A Synthesis of 8 Airborne and Field Campaigns
TERRY LATHEM, Athanasios Nenes, Georgia Institute of Technology
Abstract Number: 188 Working Group: Aerosols, Clouds, and Climate
Abstract The feedbacks among aerosols, clouds, and radiation are important components for understanding Earth’s climate system and quantifying human-induced climate change, yet the magnitude of these feedbacks remain highly uncertain. Characterizing the ability of aerosols to uptake water vapor and form cloud condensation nuclei (CCN) are key to understanding the microphysics behind cloud formation, as well as assess the impact aerosols have on the Earth system. We present a synthesis of CCN and aerosol measurements from 8 different field campaigns and for volcanic ash samples collected around the world. We investigate the CCN activity, hygroscopicity, and impact of these aerosols, which include samples of: boreal forest fires, the high arctic, the marine boundary layer, atmospheric dust, urban pollution, ship plumes, volcanic eruptions, and hurricanes. The hygroscopicity of the different aerosol is quantified by their ability to nucleate cloud drops under controlled levels of water vapor supersaturation and we further explore the origin of the particle hygroscopicity (being from the presence of deliquescent soluble material or adsorption onto insoluble surfaces). Finally, we utilize the data to make predictions of CCN formation and to test the current microphysical theories for the impact of particle chemistry on droplet formation. We find that organics dominant the particle hygroscopicity for many regions and aerosol source types. The comprehensive nature of the CCN measurements makes this a valuable data set for constraining current uncertainties associated with predicting CCN and cloud droplet number concentrations around the world.