Chemical Tomography in a Fresh Wildland Fire Plume: a Large Eddy Simulation (LES) Study | CU Experts

; Wildland fires involve complicated processes that are challenging to; represent in chemical transport models. Recent airborne measurements; reveal remarkable chemical tomography in fresh wildland fire plumes,; which remain yet to be fully explored using models. Here we present a; high-resolution large eddy simulation (LES) model coupled to chemistry; to study the chemical evolution in fresh wildland fire plume. The model; is configured for a large fire heavily sampled during the Fire Influence; on Regional to Global Environments and Air Quality (FIREX-AQ) field; campaign, and a variety of airborne measurements are used to evaluate; the chemical heterogeneity revealed by the model. We show that the model; captures the observed cross-transect variations of a number of compounds; quite well, including ozone (O; 3; ), nitrous acid (HONO),; and peroxyacetyl nitrate (PAN), etc. The combined observational and; modeling results suggest that the top and edges of fresh plume drive the; photochemistry, while dark chemistry is also present but in the lower; part of the plume. The model spatial resolution is shown to be very; important as it may shift the chemical regime, leading to biases in; O; 3; and NO; x; chemistry. Based on findings; in this work, we speculate that the impact of small fires on air quality; may be largely underestimated in models with coarse spatial resolutions.;

Wang S; Coggon MM; Gkatzelis GI; Warneke C; Bourgeois I; Ryerson TB; Peischl J; Veres PR; Neuman JA; Hair J

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