AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Polarimetric Measurement Sensitivities for Atmospherically Processed Brown Carbon Aerosol
CHENCHONG ZHANG, William Heinson, Benjamin Sumlin, Michael Garay, Olga Kalashnikova, Rajan K. Chakrabarty, Washington University in St. Louis
Abstract Number: 317 Working Group: Remote and Regional Atmospheric Aerosol
Abstract Biomass burning is an important source of brown carbon (BrC) aerosol emissions, which significantly modulate regional atmospheric radiative forcing by strongly absorbing in the near-UV solar spectrum. Because they are partially soluble in water droplets, these particles also affect cloud microphysical characteristics. Multiangle spectropolarimetric remote sensing techniques have proved very useful in characterizing the properties of the atmospheric BrC, including its composition and particle vertical distribution.
Freshly emitted BrC aerosol has been shown to quickly undergo atmospheric processing, changing its optical and physicochemical properties on time-scales ranging between minutes to hours. Current remote sensing retrieval algorithms fail to take these changes into consideration in their parameterizations of BrC aerosol microphysical properties during atmospheric processing. Here, we propose forward modeling to quantitatively analyze the sensitivity of remote sensing parameters to changing BrC aerosol properties as a function of atmospheric processing. We track the evolution of BrC aerosol after emission by configuring the atmospheric layers in a numerical model with aerosols of different aging stages. In this way, the spectropolarimetric pattern of BrC aerosol can be tracked over a long time-scale. Our forward modeling results will be validated with observational data collected by the Jet Propulsion Laboratory's Airborne Multiangle SpectroPolarimetric Imager.