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Abstract
Wildland fires promote forest ecological health but drive negative environmental impacts including those associated with smoke emissions. One important constituent of wildland-fire smoke is light-absorbing organic aerosol, or brown carbon (BrC), which exhibits significant yet poorly constrained effects on atmospheric radiative balance. Here, we investigate light-absorption properties of BrC in smoke emissions as part of the Georgia Wildland-Fire Simulation Experiment (G-WISE). G-WISE investigated differences between wildfire and prescribed fire smoke. Three burn scenarios were considered: wild (W), prescribed (Rx), and wild with a layer containing duff (partially decomposed organic material) (WDuff). W-BrC was a factor of 2.5 more absorptive than Rx-BrC and a factor of 6 more absorptive than WDuff-BrC, signifying the importance of fuel-bed composition (existence of duff) and burn conditions on BrC emissions. The importance of burn conditions was further illustrated via obtaining a strong correlation between BrC absorption and fire radiative power (FRP), calculated using infrared thermography.