Seminar

Abstract

Open biomass burning, such as wild and prescribed fires, is a significant source of aerosols to the atmosphere, greatly influencing both climate and human health. These biomass burning particles evolve in both size and composition within the smoke plumes, affecting the particles’ abilities to act as cloud condensation nuclei, interact with radiation, and impact climate. However, this particle evolution differs between fires, being strongly influenced by aerosol concentrations in the plumes. Aerosol mass concentrations in a plume of a small fire (think agricultural field) will dilute to <1 µg m^-3 in seconds or minutes due to the short dilution length scale. On the other hand, the PM in large wildfires may remain >100 µg m^-3 or even >1000 µg m^-3 for hours or days. These concentration differences greatly impact the evolution of aerosol size and composition. Further, individual smoke plumes may have strong variability in concentrations across the plume, particularly if smoke is injected into multiple atmospheric layers (e.g., surface and free troposphere) from the same fire. In this talk, I will discuss how field work and high-resolution modeling has elucidated the roll of plume concentrations on inter- and intra-plume variability in smoke aging.

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Jeff Pierce is a Professor at the Department of Atmospheric Science, Colorado State University. His group's research focuses on atmospheric aerosols, their physical and chemical evolution in the atmosphere, and their impacts on climate and health. They aim to blend models and observations to learn cool new things! He currently serves on NASA's Health and Air Quality Applied Science Team (HAQAST) and is an author of the current US National Climate Assessment.