Quantifying the Influence of Biomass Burning on Measurement Sites in the Western U.S.

Abstract:

Understanding and quantifying the impact of biomass burning on measurement sites in the Western U.S. is important, as fire activity is thought to be strengthening due to climate change while population growth across the West has been increasing the number of people exposed to these wildfires. Fires can emit large quantities of species relevant for air quality, as well as carbon-containing gases (CO₂, CO, CH₄), thereby making it a source of carbon to the atmosphere. The intense, highly varying, and often localized nature of fire emissions render it difficult for models to capture the impact of biomass burning on atmospheric distributions of CO₂ and other trace gases, particularly with emission inventories at resolutions that are coarse in comparison to the spatiotemporal variability of actual fires.

In this study, we present simulations of CO₂, CO, and PM_2.5 at measurement sites in the Western U.S. The modeling framework consists of (1) Receptor-oriented Lagrangian particle dispersion model simulations from the Stochastic Time-Inverted Lagrangian Transport (STILT) model; (2) Nested meteorological fields from the Weather Research and Forecasting (WRF) model; and (3) High-resolution wildland fire emission inventories from the Missoula Fire Sciences Laboratory covering the entire Western U.S. The modeling framework enables researchers to investigate and quantify the impact of biomass burning emissions on trace gas sampling sites. For CO₂, we will compare our estimates against values from NOAA’s CarbonTracker simulations. Differences from other existing emission inventories (e.g., GFED, FINN) will also be quantified. Examples will be shown at selected sites across the Western U.S, on mountains as well as lower elevations.