Sampling Biases of Space-Based Observations of XCO2 Associated with South American Biomass Burning Events during 2017-2020

The Amazon rainforest in Brazil experiences an annual burning season during August-September due to rain abatement. After the launches of OCO-2 and OCO-3, the density of space-based observations of biomass burning events has increased, though these observations can be influenced by smoke, pyrocumulous, or other atmospheric phenomena. We use observations of carbon monoxide from Atmospheric Infrared Sounder (AIRS) on NASA’s Aqua satellite and Aerosol Optical Depth (AOD) from Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite as tracers for biomass burning events during the Brazilian wildfire seasons from 2017-2020. We examine the density of successful XCO2 observations from OCO-2 and OCO-3 data correlated with fires during this time period and utilize NOAA ObsPack aircraft profiles over the region as validation. We will quantify how the selection effects impact XCO2 observations in the vicinity of large fires by separating the observations into polluted (high CO [dry-air ppbv]) and clean (low CO [dry-air ppbv]) regions using OCO-2, and OCO-3 observations matched up in time and space with AIRS observations.