Thermodynamically Constrained Fire Radiative Power Retrieval Approach for Estimating Wildfire Emissions during the 2019 FIREX-AQ Campaign

CHENCHONG ZHANG, Nishit Shetty, Benjamin Sumlin, Rajan K. Chakrabarty, Washington University in St. Louis

     Abstract Number: 180
     Working Group: Aerosols, Clouds and Climate

Abstract
Biomass burning (BB) degrades regional air quality by emitting tons of gases and particulate matters. Besides the greenhouse gases, BB represents a large source of non-methane volatile organic compounds (NMVOCs), which will further form secondary organic aerosol (SOA) by gas-phase oxidation and vapor-pressure-driven partitioning. BB primary emissions have been widely estimated by the bottom-up approach, which is the product of the burned area, the fraction of burned biomass, biomass fuel load, and the specific emission factors. However, the burned areas are frequently underestimated by the existing subpixel algorithms compared to in situ measurements. Here we synergistically integrate the high-spatiotemporal-resolution fire radiative power (FRP) with a comprehensive soil heat transfer model to accurately estimate the primary pollutant emissions during the 2019 Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) campaign. We resolve the diurnal FRP cycle of large-scale fires at a 5-min interval from the Geostationary Operational Environmental Satellite (GOES). FRP of other small-scale wildfires captured by Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) are extrapolated based on the similar diurnal pattern retrieved by GOES. The fused datasets of FRP by both geostationary and polar-orbiting satellites are incorporated into our thermodynamically-constrained retrieval model to resolve the fire area which contributes primary emissions, and a complete temperature profile of both the fire area and adjacent heated land. The estimated primary emissions of greenhouse gases and particulate matters show improved correlation with the integrated airborne in situ measurements. The computed NMVOC emissions are input into a regional chemical transport models to give a reliable estimation of total particulate matter emissions.