Light Absorbing Aerosol-Cloud Interactions

SHREYA JOSHI, Claudio Mazzoleni, Timothy Onasch, Arthur J. Sedlacek, Raymond Shaw, Ian Helman, Susan Mathai, Thusitha Divisekara, Swarup China, Abu Sayeed Md Shawon, Laura Fierce, Yangang Liu, Lynn Mazzoleni, Simeon Schum, Will Cantrell, Jacob Kuntzleman, Michigan Technological University

     Abstract Number: 462
     Working Group: Aerosols, Clouds and Climate

Abstract
Atmospheric light-absorbing aerosols, such as particles containing black carbon (BC), significantly impact the Earth’s radiation budget. These particles interact with solar radiation, scattering, and absorbing light, as well as with clouds. Morphological changes of BC and internal mixing with other materials, such as organic coatings, affect the particle's scattering and absorption properties and their interaction with clouds. These processes have been the subject of previous studies; however, interactions of BC with clouds have received less attention, and important questions remain open. Recently, we started a project designed to investigate these processes in the Michigan Tech cloud chamber (the Pi-Chamber). We will be using BC and BC surrogates and coating surrogates to understand better the effects of aging on aerosol-cloud interactions. Initial experiments were carried out to characterize the dry deposition in the Pi-Chamber for aerodynamically size selected BC particles. Cloud experiments are currently being carried out employing a Pumped Counterflow Virtual Impactor to investigate changes in the morphology of the BC particle aggregates upon cloud activation and evaporation. During these experiments, we study the changes in optical and cloud condensation nuclei properties of interstitial and residual particles. We also characterize the optical and chemical properties of liquid smoke, which will be used as a surrogate for BC coating. Subsequent experiments will focus on the effects of coating material on BC, how these coatings affect aerosol-cloud interactions, and the resulting aerosol and cloud properties. We will provide an overview of the project and some preliminary results.