Abstract View
Predicting Effect of Organic-Inorganic Internally Mixed Particles on Water Uptake and Optical Properties of Atmospheric Aerosols
LUCY NANDY, Yu Yao, Nicole Riemer, University of Illinois at Urbana-Champaign
Abstract Number: 517
Working Group: Aerosols, Clouds and Climate
Abstract
To study the impact of aerosol particles on Earth’s climate, there are important parameters like, the particle size, water content, chemical composition, to consider when estimating their optical properties. This study while considering these factors, assumes that the particles are spherical in shape and are internally mixed. The aim is to predict the water uptake by submicron dry particles at water sub-saturation, determining the size distribution of the dry and wet particles, and the optical properties with and without hydrophobic black carbon in the particle core, focusing on the absorption enhancement by black carbon. The hygroscopic growth determined by using a lattice-based adsorption isotherm model in this study is found to differ by upto 50% for particles containing high fractions of organic matter than using existing aerosol models (e.g. MOSAIC, κ-Köhler parameterization) generally used in regional/global climate models. It is also found that the particles scatter and absorb more solar radiation in the visible spectrum than most predictions. To study absorption properties, black carbon is assumed to be in the core of these particles, and we have found that the single scattering albedo (ω) is higher by upto 1 - 2% than the other model calculations at high relative humidities and organic mass fractions. This study while elucidating the discrepancies, could reduce uncertainty in radiative forcing by improved aerosol water uptake estimations/parameterization required by the climate models.