37CVC Wildfires and Greenhouse Gases across the Southwestern USA

This study leverages satellite data and chemistry transport models to analyze the impact of wildfires on trace gases in California during the August-October periods of 2018, 2019, and 2020. During these months, Southern California experiences minimal precipitation, leading to a high Vapor Pressure Deficit (VPD), which results in decreased photosynthetic activities. This reduction, combined with the increase in biomass burning, causes a rise in CO₂ concentrations, as observed by the OCO-2 satellite. The dry season also witnesses increased CO and CH₄ levels, tied to the surge in biomass burning, as detected in TROPOMI retrievals. The CarbonTracker model captures these elevated CO₂ concentrations, though with a somewhat reduced amplitude. Similarly, the GEOS-Chem model successfully simulates higher CO levels but underestimates the observed enhancements. These findings will contribute to an improved understanding of fire's influence on trace gases and aid in refining future numerical models.