Airborne Observations of Aerosol Absorption and Brown Carbon in Wildfire Emissions during WE-CAN 2018

The net radiative impact of aerosol emissions from wildfires remains a significant uncertainty in regional and global climate models. One important source of uncertainty is aerosol radiative properties. During the WE-CAN field campaign in 2018 aerosol absorption, scattering and extinction were measured in emissions from a wide-range of wildfires burning a variety of fuels at different combustion efficiencies in the Western United States. Flights on the NCAR C-130 aircraft demonstrated that it is feasible to make sensitive measurements of aerosol absorption at multiple wavelengths with a custom photoacoustic absorption spectrometer (PAS) on an airborne platform. Data presented will show the impact of photochemical aging, dilution and injection height on aerosol absorption and the spectral properties of brown carbon. Novel observations of absorption in smoke-impacted cloud droplet residuals measured through a counterflow virtual impactor will also be presented.