Black Carbon Mixing State Evolution in Shallow and Deep Convective Wildfire Plumes
MANVENDRA DUBEY, James E. Lee, Kyle Gorkowski, Ryan Farley, Katherine Benedict, Allison Aiken, Eunmo Koo, Jon Reisner, Los Alamos National Laboratory
Abstract Number: 392
Working Group: Aerosols, Clouds and Climate
Abstract
Black carbon (BC) mixing state (internal, coated (core-shell or extruded), or external) determines the optical and hygroscopic properties of smoke emitted by wildfires and their effects on climate. Organic carbon (OC) and water coated BC can enhance light absorption. While fresh BC is hydrophobic, mixing with hydrophilic species can reduce its burden and promote cloud formation and evaporation. Field observations of BC coating thickness in shallow smoke plumes reveal growth in the near field by condensation and coagulation followed by a decline by evaporation.1 Observations of aged wildfire smoke plumes transported over long range show coating effects that depend on environmental conditions.2,3 Finally, recent observations of thickly coated BC particles injected into stratosphere injected by deep convective Pyrocumulous events identify a new regime that is not well understood.4 We develop a reduced order modeling and analysis framework to understand evolution of BC mixing as a function of OC, photochemistry, temperature, humidity, and cloud processing to understand these different coating behaviors.5 We discuss how cloud chamber studies can help elucidate these complex effects. Top-down field observations and bottom-up cloud chamber experiments should help develop validated or empirical BC mixing state parametrizations in climate models.
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[2] Lee, J. E. et al. Geophys. Res. Lett., 49, e2022GL099334, 2022.
[3] Lee, J. E. et al. JGR: Atm, 125, e2020JD032399, 2020.
[4] Katich, J. M. et al. Science, 379, 815–820, 2023.
[5] Gorkowski, K. et al. Environ. Sci.: Atmos., 4, 80-87, 2024.